摘要:

I I I I I I I I I I I I I I 1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY NOVEMBER 1996 READER ENQUIRY SERVICE For further information about any of the products featured in the advertisements in this issue please write the appropriate number in one of the boxes below. Postage paid if posted in the British Isles but overseas readers must affix a stamp. PLEASE USE BLOCK CAPITALS LEAVING A SPACE BETWEEN WORDS Valid 12 months 1 NAME I I I I 1 I T T I I l I I I I I I I I I l l l l l l l l l l l I l ~ l l l l l l l l l l l l l l l l l l l l l l l l l E I m I n I l l l l l l l l l l l l l l l l l l l l 1 1 1 1 1 c I I u I I I l I I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I I I 6 COUNTRY ~ l l l l l l l l l l l l l l l l l l l l l l l l l 2 COMPANY PLEASE GIVE YOUR BUSINESS ADDRESS IF POSSIBLE IF NOT PLEASE TICK HERE [7 3 STREET 4 TOWN 5 COUNTY POSTCODE -1 I I I I 1 1 I I I 1 1 I I I I I I I I I I I I I 7 DEPARTMENT DIVISION -1 I I I I I I I I I 1 1 I. I I I I I I I I I I 1 1 POSITION -1 I I I I I I I I I I I I I I I I I I I I 1 1 I I -= OFFICE USE ONLY REC.D PHOC D 8 YOUR JOB TITLE 9 TELEPHONE NO FOLD HERE I - - - - - - - - - - - - I I I I I I I Post age will be I paid by I Licensee I I I I I I I I I I I I I I I I I I I I I I I I I BUSINESS REPLY SERVICE Licence No.WD 106 Reader Enquiry Service Journal of Analytical Atomic Spectrometry The Royal Society of Chemistry Burlington House Piccadilly LONDON WIE 6WF England1997 European Winter Conference on Plasma Spectrochemistry Gent Belgium January 12-17 1997 Since 1980 the Winter Conference on Plasma Spectrochemistry has been organized biennially in the USA and since 1983 has become an annual event which alternates between the USA and Europe. It has acquired an international reputation as the world's premier meeting covering state-of-the-art developments in all aspects of plasma spectrochemistry. The 1997 conference to be held at the University of Gent (Ghent) Belgium will feature developments in plasma spectrochemical analysis by inductively coupled plasma (ICP) dc plasma (DCP) microwave induced plasma (MIP) and glow discharge (GD) sources coupled to atomic emission or mass spectrometers.In addition current trends and future directions in novel sample introduction systems plasma system automation and software for data handling will be discussed by recognised world authorities with emphasis on elemental speciation studies high resolution ICP-MS spectrometry accuracy of the results quality assurance and industrial applications. The meeting will comprise oral and poster presentations short courses and a five day exhibition of spectroscopic instrumentation and accessories. Scientific Programme The scientific programme will include the major topics of plasma spectrochemistry. Each topic will be introduced by an invited lecturer who is an expert in the field.The main topics are 1) Instrumentation and software; 2) Sample introduction and transport phenomena; 3) Elemental speciation; 4) High resolution ICP-MS; 5) Solid sampling; 6) Glow discharge; 7) Applications; 8) Accuracy and quality assurance; and 9) Stable isotope analysis. Schedule of Activities Preliminary title and 50-word abstracts June 15 1996 Notification of accepted papers September 15 1996 Final abstracts November 1 1996 Early pre-registration. Deadline November 1 1996 Hotel pre-registration. Deadline November 1 1996 Late pre-registration. Deadline December 15 1996 Publication of Papers The proceedings of the 1997 European Winter Conference will appear in the autumn of 1997 in a special issue of Journal of Analytical Atomic Spectrometry (JAAS). After peer review manuscripts of accepted papers will be considered for publication in these proceedings.Local Organizing Committee R. Dams University of Gent (Chairman) L. Moens University of Gent (Secretrary) J. Broekaert University of Dortmund Germany R. Cornelis University of Gent R. Gijbels University of Antwerpen F. Vanhaecke University of Gent L. Van 't dack University of Antwerpen C. Vandecasteele University of Leuven P. Taylor IRMM Joint Research Centre EC P. Quevauviller Measurements and Testing EC I For further information please contact L. Moens Secretariat 1997 European Winter Conference Laboratory of Analytical Chemistry University of Gent Proeftuinstraat 86 B-9000 Web page http://www.rug.ac.be.~ Gent Belgium. Tel +32 9 264 44 00; Fax +32 9 264 66 99; E-mail plasma97@rug.ac.be;The Society for Applied Spectroscopy... KEEP ABREAST OF NEW AND INNOVATIVE TECHNOLOGY .... Our Society can provide you with the latest in research technology and practical knowledge. We also provide the essential link for networking with your peers - with options such as a membership directory internet access and an annual conference. There are awards for achievements student programs and on-line services. Membership entitles you to receive a subscription to Applied Spectroscopy. This monthly publication features papers on all areas of spectroscopy and contains advertisements fiom leading companies in the field. It is a valuable resource for those who wish to remain informed of today's technology and research and for those providing quality resource materials.You will be eligible to receive r e d u d rates on other scientific journals e.g. Spectrochemicaf Acta B JAAS and AnaZyticaf Chemistry. Receive a discount on the registration fees for FACSS the worlds' leading conference in spectroscopy and analytical chemistry. We provide educational courses at a discount to members which can be used as a tool to increase on-the-job performance. Learn fundamental and practical instrumentation analytical methodology and sample applications through these educational courses. We are confident you will be impressed and will want to become a member of our prestigious Society. We look forward to hearing from you in the near future.Please fill out the form below and fax or mail it to SAS OOl(301) 694-8122 - Phone 201 B Broadway Street OOl(301) 694-6860 - Far Frederick MD. 21701 USA TinaKsas@aol.com - E-mail 8 8 YES enroll me as an SAS member today! . 8 8 RATES USA CANAD,d OUTSIDE USA MEMBER $65.00 $80.00 $105.00 STUDENT $20.00 $35.00 $ 60.00 Please circle one! 8 RETIREE $20.00 8 8 8 Name 8 Company 8 ' Address m Province Postal Code Country 8 8 Phone Fax E-mail (include country code) 8 8 8 8 8 MY position fits the following category OAcademic OInstrument Company OConsdtant OGovemment ORetiree OStudent OClinical Lab OCommercial Lab OIndustry(Type ) 8 m OOther My check is enclosed 0 Invoice Me 0 Bill my MCNISNAMX 0 8 8 8 8 8 8 8 8 . 8 8 8 8 Credit Card Number Expiration Date 8 8 8 8 8 8 signature 8 JAASPROM ' CHECKS MUST BE IN US FUNDS DRAWN ON A US BANK! 8 m 8 8 ~ 8 .8 m m 8 m m 8 8 . 8 8 8 8 8 8 m 8 8 8 8 8 8 8 8 8 8 m 8 m m 8 m 8 ~ m m m m m 8 ~ m m m m ~ m ~18th INTERNATIONAL GEOCHEMICAL EXPLORATION SYMPOSIUM Jerusalem Israel May 25 - 29 1997 Ron Bogoch and Moshe Shirav (Co-Chairmen) Geological Survey of Israel Michael Beyth Earth Science Administration Ministry of Energy and Infrastructure Joe Brenner Geological Survey of Israel Yuval Cohen Israel Oceanographic and Limnological Research Haifa Yigal Erel Hebrew University of Jerusalem George Constantinou Director Geological Survey Department Cyprus Shimon Feinstein Ben Gurion University of the Negev Beer Sheva Yehoshua Kolodny The Hebrew University of Jerusalem Jerusalem Joel Kronfeld Tel Aviv University Yair Levy Rotem Amfert Negev Ltd.(Negev Phosphates) Yoseph Nachmias PAMA (Energy Resources Development) Ltd. Aryeh Nissenbaum The Weizmann Institute of Science Rehovot Naomi Porat Geological Survey of Israel Steve Tandy Dead Sea Works Ltd. For further information contact The Symposium Secretariat The 18th International Geochemical Exploration Symposium P.O. Box 50006 Tel Aviv 61500 Israel. Tel 972 3 5140000; Fax 972 3 5175674/5140077; E-mail for Compuserve Users ccmail:IGES at Kenes for Internet users lGES@ Kenes.ccmaiI.cornpuserve.com. i The symposium represents a broad spectrum of topics including those not previously given such as the geochemistry of radon and the importance of geochemistry in archaeology.The two field trips in Israel to the north and south of the country will provide participants with a complete spectrum of the geology various ongoing geochemical projects and include sites of historic interest. The field trip in Cyprus organized by the Geological Survey Department in Nicosia will include a visit to the famous Troodos Ophiolite Complex as well as locations of metallic deposits. Symposium themes arid zone geochemistry; advances in geochemical mapping; data processing; exploration geochemistry in the Mediterranean area and Africa; advances in analytical techniques; environmental geochemistry; organic matter and biogeochemistry in geochemical exploration; hydrogeochemistry and environmental hydrogeochemistry; mitigation of environmental impact from mining and waste disposal; geochemistry of radon; geochemistry and archaeology; radioactive tracers and remote sensing in exploration.A commercial exhibition will be held in conjunction with the Symposium further details from the Symposium Secretariat. Call for papers participants are invited to submit abstracts on any of the above mentioned themes on other related topics including case studies and/or to propose additional themes. The Journal of Geochemical Exploration will publish a special issue of full papers to be presented at the Symposium. The papers will be divided into oral presentations and posters - authors are asked to express a preference. Deadline for submissions is December 15 1996. Workshops (May 30) Modern Techniques in Geochemical Analysis An Update Environmental and Legislative Uses of Regional Geochemical Baseline Data for Sustainable Development Morpho- and Soil Stratigraphy of Alluvial Sediments in Arid Zone Regions Geochemistry of Radon Hydrochemistry Sampling and Analytical Techniques Environmental Impact Global Geochemical Baselines. Registration (by February 24 1997) Symposium US$ 300 Workshop US$80 Local Organizing Committee

ISSN:0267-9477    

DOI:10.1039/JA99611BP025

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

Journal of Analytical Atomic Spectrometry 111 111111111 111111 111 111111111 111111 THE ROYAL C H EM I ST RY Information Services I I JASPE2 11 (1 2) 53N-58N 11 29-1 234 461 R-522R CONTENTS NEWS PAGES Editorial-Steve J. Hill Guest Editors Foreword-Joseph A. Caruso Steve J. Hill Diary of Conferences and Courses Future Issues 53N 53N 54N 55N 57N PAPERS Trace Metal Speciation via Supercritical Fluid Extraction-Liquid Chromatography-Inductively Coupled Plasma Mass Spectrohetry Nohora P. Vela Joseph A. Caruso Low-flow Interface for Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry Speciation Using an Oscillating Capillary Nebulizer Lanqing Wang Sheldon W. May Richard F. Browner Stanley H. Pollock 1129 1137 Effect of Different Spray Chambers on the Determination of Organotin Compounds by High-performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry Cristina Rivas Les Ebdon Steve J.Hill 1147 Feasibility Study of Low Pressure Inductively Coupled Plasma Mass Spectrometry for Qualitative and Quantitative Speciation Gavin O’Connor Les Ebdon E. Hywel Evans Hong Ding Lisa K. Olson Joseph A. Caruso 1151 Speciation of Inorganic Selenium and Selenoaminoacids by On-line Reversed- phase High-performance Liquid Chromatography-Focused Microwave Digestion-Hydride Generation-atomic Detection J. M. Gonzalez Lafuente M. L. Fernandez Sanchez A. Sanz-Medel 11 63 Speciation of Organic Selenium Compounds by High-performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry in Natural Samples Riansares MuAoz Olivas Olivier F.X. Donard Nicole Gilon Martine Potin-Gautier Investigation of Selenium Speciation in In Vitro Gastrointestinal Extracts of Cooked Cod by High-performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry and Electrospray Mass Spectrometry Helen M. Crews Philip A. Clarke D. John Lewis Linda M. Owen Paul R. Strutt Andres lzquierdo Approaches to the Determination of Metallothionein(s) by High-performance Liquid Chromatography-Quartz Tube Atomic Absorption Spectrometry Yanxi Tan Patrick Ager William D. Marshall Hing Man Chan Speciation of Some Metals in River Surface Water Rain and Snow and the Interactions of These Metals With Selected Soil Matrices J. Y. Lu C. L. Chakrabarti M. H. Back A. L. R. Sekaly D. C. Gregoire W. H.Schroeder 1171 1177 1183 1189 Investigations Into Chromium Speciation by Electrospray Mass Spectrometry Ian 1. Stewart Gary Horlick Arsenic Speciation by Liquid Chromatography Coupled With lonspray Tandem Mass Spectrometry Jay J. Corr Erik H. Larsen 1203 1215 Atomic Spectrometry Hyphenated to Chromatography for Elemental Speciation Performance Assessment Within the Standards Measurements and Testing Programme (Community Bureau of Reference) of the European Union Philippe Quevauviller CUMULATIVE AUTHOR INDEX 1225 1233 AT0 M I C SPECTROMETRY UPDATES Industrial Analysis Metals Chemicals and Advanced Materials- James S. Crighton John Carroll Ben Fairman Janice Haines Mike Hinds 461 R References Typeset printed and bound by The Charlesworth Group Huddersfield England 01484 51 7077 509R 0267-9477(1996112:1-6Journal of Analytical Atomic Spectrometry JAAS Editorial Board Chairman B.L. Sharp (Loughborough UK) H. Crews (Norwich UK) A. T. Ellis (Abingdon UK) S. J. Haswell (Hull UK) S. J. Hill (Plymouth UK) B. P. Holliday (Cambridge UK) R. C. Hutton (Cheshire UK) D. Littlejohn (Glasgow U K I A. Sanz-Medel (Oviedo Spain) P. D. P. Taylor (Geel Belgirm) JAAS Advisory Board F. C. Adams (Antwerp Belgium) R. M. Barnes (Amherst MA USA) L. Bezur (Budapest Hungary) M. W. Blades (Vancouver Canada) R. F. Browner (Atlanta GA USA) J. L. Burguera (Merida Venezuela) S. Caroli (Rome Italy) J. A. Caruso (Cincinnati OH USA) A. J. Curtius (Florianopolis Brazil) J. B. Dawson (Leeds UK) M. T. C. de Loos-Vollebregt (Delft The Netherlands) 0. F. X.Donard (Talence France) L. Ebdon (Plymouth UK) M. S. Epstein (Gaithersburg MD USA) Fang Zhao-tun (Shenyang China) W. Frech (UmeH Sweden) A. K. Gilmutdinov (Kazan Russia) G. M. Hieftje (Bloomington IN USA) R. S. Houk (Ames / A USA) R. Klockenkamper (Dortmund Germany) B. V. L'vov (St. Petersburg Russia) R. K. Marcus (Clemson SC USA) J. M. Merrnet (Villeurbanne France) T. Nakahara (Osaka Japan) Ni Zhe-ming (Beuing China) J. W. Olesik (ColumBus OH USA) N. Omenetto (Ispra Italy) C. J. Park (Taejon Korea) P. J. Potts (Milton Keynes UK) R. E. Sturgeon (Ottawa Canada) V. Sychra (Prague Czech Republic) S. Tanner (Concord Canada) P. Van Espen (Antwerp Belgium) R. Van Grieken (Antwerp Belgium) B. Welz (Uberlingen. Germany) Atomic Spectrometry Updates Editorial Board Chairman *A.T. Ellis (Abingdon UK) J. A. Armstrong (Edinburgh UK) *J. R. Bacon (Aberdeen UK) R. M. Barnes (Amherst MA USA) S. Branch (High Wycombe UK) R. Bye (Oslo Norway) J. Carroll (Middlesbrough UK) M. R. Cave (Keyworth UK) S. R. N. Chenery (Keyworth UK) +J. M. Cook (Keyworth UK) J. S. Crain (Argonne IL USA) *M. S. Cresser (Aberdeen UK) H. M. Crews (Norwich UK) J. S. Crighton (Sunbury-on-Thames UK) *J. 8. Dawson (Leeds UK) J. R. Dean (Newcastle upon Tyne UK) *E. H. Evans (Plymouth UK) J. Fazakas (Budapest Hungary) A. Fisher (Plymouth UK) L. M. Garden (Middlesbrough UK) +J. M. Gordon (Cambridge UK) D. J. Halls (Glasgow UK) *S. J. Hill (Plymouth UK) *B. Holliday (Cambridge UK) K. W. Jackson (Albany NY USA) R. Jowitt (Middlesbrough UK ) K. Kitagawa (Nagoya Japan) J.Kubova (Bratislava Slovak Republic) *J. Marshall (Middlesbrough UK) H. Matusiewicz (Poznan Poland) A. W. McMahon (Manchester UK) R. G. Michel (Storrs CT USA) *D. L. Miles (Keyworth UK T. Nakahara (Osaka Japarr) Ni Zhe-ming (Beijing China) L. M. W. Owen (Norwich UK) P. J. Potts (Milton Keynes UK) W. J. Price (Budleigh Salterton UK) C. J. Rademeyer (Pretoria South Africa) A. Sanz-Medel (Oviedo Spain) *B. L. Sharp (Loughborough UK) 1. L. Shuttler (Uberlingen Germany) M. Sperling (Uberlingen G'ermany) R. Stephens (Halifax Canada) C. Streli (Vienna Austria) J. Stupar (Ljubljana Slovenia) R. E. Sturgeon (Ottawa Canada) *A. Taylor (Guildford UK) G. C. Turk (Gaithersburg MD USA) J. F. Tyson (Amherst MA USA) P. J. Watkins (London UK) M. White (Ispra Italy) J. G. Williams (Egham UK) P.Wobrauschek (Vienna Austria) *Members of the ASU Executive Committee Managing Editor JAAS Brenda Holliday The Royal Society of Chemistry Thomas Graham House Science Park Milton Road Cambridge CB4 4WF UK. Telephone + 44 (0) 1223 420066. Fax + 44 (0) 1223 420247. E-mail RSCl @RSC.ORG (Internet) Deputy Editor Sarah Williams Production Manager Janice Gordon Production Editor Caroline Seeley Technical Editors Ziva Whitelock Roger Young Editorial Secretaries Lesley Turney Claire Harris Frances Thompson American Associate Editor JAAS Dr. J. M. Harnly US Department of Agriculture Beltsville Human Nutrition Research Center Beltsville MD 20705 USA. Telephone + 1 301 -504-856'3 Fax +1 301 504 8314 E-mail harnly@bhnrc.usda.g80v Asia-Pacific Associate Editor JAAS Prof.N. Furuta Department of Applied Chemistry Faculty of Science and Engineering Chuo University 1-1 3-27 Kasuga Bunkyo-ku Tokyo 112 Japan. Telephone 81 -3-381 7-1 906. Fax 81 -3-381 7-1 895. E-mail nfuruta@apchern.chem.chuo-u.ac.jp Advertisements Advertisement Department The Royal Society of Chemistry Thomas Graham House Science Park Milton Road Cambridge UK CB4 4WF. Telephone + 44 (0) 1223 432243. Fax + 44 (0) 1223 42601 7. Information for Authors Full details of how to submit materials for publi- cation in JAAS are given in the Instructions to Authors in Issue 1. Separate copies are available on request. The Journal of Analytical Atomic Spectrometry (JAAS) is an international journal for the publi- cation of original research papers communi- cations and letters concerned with the development and analytical application of atomic spectrometric techniques.The journal is pub- lished twelve times a year including comprehen- sive reviews of specific topics of interest to practising atomic spectroscopists and incorpor- ates the literature reviews which were previously published in Annual Reports on Analytical Atomic Spectroscopy (ARMS). Manuscripts intended for publication must describe original work related to atomic spectro- metric analysis. Papers on all aspects of the sub- ject will be accepted including fundamental studies novel instrument developments and prac- tical analytical applications. As well as AAS AES and AFS papers will be welcomed on atomic mass spectrometry X-ray fluorescence/emission spectrometry and secondary emission spec- trometry.Papers describing the measurement of molecular species where these relate to the characterization of sources normally used for the production of atoms or are concerned for example with indirect methods of analysis will also be acceptable for publication. Papers describing the development and applications of hybrid techniques (e.g. GC-coupled AAS and HPLC-ICP) will be particularly welcome. Manuscripts on other subjects of direct interest to atomic spectroscopists including sample prep- aration and dissolution and analyte pre-concen- tration procedures as well as the statistical interpretation and use of atomic spectrometric data will also be acceptable for publication. There is no page charge. The following types of papers will be considered.Full papers describing original work. Communications which must be on an urgent matter and be of obvious scientific importance. Communications receive priority and are usually published within 2-3 months of receipt. They are intended for brief descriptions of work that has progressed to a stage at which it is likely to be valuable to workers faced with similar problems. Reviews which must be a critical evaluation of the existing state of knowledge on a particular facet of analytical spectrometry. Every paper (except Communications) will be submitted to at least two referees by whose advice the Editorial Board of JAAS will be guided as to its acceptance or rejection. Papers that are accepted must not be published elsewhere except by permission. Submission of a manuscript will be regarded as an undertaking that the same material is not being considered for publication by another journal.Manuscripts (three copies typed in double spacing) should be sent to Brenda Holliday Managing Editor JAAS Dr. J. M. Harnly US Associate Editor JAAS or Prof. N. Furuta Asia- Pacific Associate Editor JAAS. All queries relating to the presentation and sub- mission of papers and any correspondence regarding accepted papers and proofs should be directed to the Editor or Associate Editors (addresses as above). Members of the JAAS Editorial Board (who may be contacted directly or via the Editorial Off ice) would welcome comments suggestions and advice on general policy matters concerning JAAS. Fifty reprints are supplied free of charge.Journal of Analytical Atomic Spectrometry (JAAS) (ISSN 0267-9477) is published morithly by The Royal Society of Chemistry Thomas Graham House Science Park Milton Road Cambridge CB4 4WF UK. All orders accompanied with payment should be sent directly to The Royal Society of Chemistry Turpin Distribution Services Ltd. Blackhorse Road Letchworth Herts. SG6 lHN UK Tel. +44 (0) 1462 672555; Telex 825372 Turpin G; Fax +44 (0) 1462 480947. Turpin Distribution Services Ltd. is wholly owned by The Royal Society of Chemistry. 1996 Annual subscription rate EEA f599.00 USA $1136.00 Rest of World f614.00. Customers should make payments by cheque in sterling payable on a UK clearing bank or in US dollars payable on a US clearing bank. Air freight and mailing in the USA by Publications Expediting Inc. 200 Meacham Avenue Elmont NY 11003. USA Postmaster send address changes to Journal of Analytical Atomic Spectrometry (JAAS) Publications Expediting Inc. 200 Meacham Avenue Elmont NY 11003. Postage paid at Jamaica NY 11 431. All other despatches outside the UK by Bulk Airmail within Europe Accelerated Surface Post outside Europe. PRINTED IN THE UK. @The Royal Society of Chemistry 1996. All rights reserved. No part of this publicatiori may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photographic recording or otherwise without the prior permission of the publishers.

ISSN:0267-9477    

DOI:10.1039/JA99611FX047

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

GLOSSARY OF ABBREVIATIONS Whenever suitable elements may be referred to by their chemical symbols and compounds by their formulae. The following abbreviations may be used without definition. ac AA AAS AE AES AF AFS AOAC APDC ASV BCR CCP CMP CRM cv cw dc DCP DDC DMF DNA ECD EDL EDTA EDXRF EIE EPMA ETA ETAAS ETV EXAFS FAAS FAB FAES FAFS FANES FAPES FI FPD FT FTMS GC GD GDL GDMS Ge ( Li ) HCL hf HG HPGe HPLC IAEA IBMK ICP ICP-MS ID IR IUPAC LA LC alternating current atomic absorption atomic absorption spectrometry atomic emission atomic emission spectrometry atomic fluorescence atomic fluorescence spectrometry Association of Official Analytical Chemists ammonium pyrrolidinedithiocarbamate anodic-s tripping vol tamme try Community Bureau of Reference capacitively coupled plasma capacitively coupled microwave plasma certified reference material cold vapour continuous wave direct current dc plasma diet h yldi thiocarbamate N N-dimethylformamide deoxyribonucleic acid electron capture detection electrodeless discharge lamp e t h ylenediamine tetraacetic acid energy dispersive X-ray fluorescence easily ionizable element electron probe microanalysis electrothermal atomization electrothermal atomic absorption spectrometr y electrothermal vaporization extended X-ray absorption fine structure flame AAS fast atom bombardment flame AES flame AFS furnace atomic non-thermal excitation spectrometry furnace atomization plasma excitation spectrometry flow injection flame photometric detector Fourier transform Fourier transform mass spectrometry gas chromatography glow discharge glow discharge lamp glow discharge mass spectrometry lithium-drifted germanium hollow cathode lamp high frequency hydride generation high-purity germanium high-performance liquid chromatography International Atomic Energy Agency isobutyl methyl ketone (4-methylpentan-2-onc.) inductively coupled plasma inductively coupled plasma mass spectrometry isotope dilution infrared International Union of Pure and Applied Chemistry laser ablation liquid chromatography (ammonium pyrrolidin-1-yl dithioformate) spectroscopy LEAFS LEI LMMS LOD LOQ LTE MECA MIP MS NAA NaDDC NIES NIST NTA OES PIGE PIXE PMT PPm PTFE PVC QC rf REE(s) RIMS RM RSD SEC SEM SFC Si (Li) SIMAAC SIMS SR SRM SSMS STPF TCA TIMS TLC TMAH TOP0 TRIS TXRF uhf uv VDU vuv WDXRF XRF PPb SIB SIN uvpr s laser-excited atomic fluorescence spectrometry laser-enhanced ionization laser-microprobe mass spectrometry limit of detection limit of quantification local thermal equilibrium molecular emission cavity analysis microwave-induced plasma mass spectrometry neutron activation analysis sodium diethyldithiocarbamate National Institute for Environmental Studies National Institute of Standards and Technology nitrilotriacetic acid optical emission spectrometry particle-induced gamma-ray emission particle-induced X-ray emission photomultiplier tube parts per billion parts per million poly (tetrafluoroethylene) poly(viny1 chloride) quality control radio frequency rare earth element(s) resonance ionization mass spectrometry reference material relative standard deviation signal-to-background ratio size-exclusion chromatography scanning electron microscopy supercritical fluid chromatography lithium-drifted silicon simultaneous multi-element analysis with a continuum source secondary ion mass spectrometry signal-to-noise ratio synchrotron radiation Standard Reference Material spark source mass spectrometry stabilized temperature platform furnace trichloroacetic acid thermal ionization mass spectrometry thin-layer chromatography tetramethylammonium hydroxide trioctylphosphine oxide 2-amino-2-( hydroxymethyl)propane-1,3-diol total reflection X-ray fluorescence ultra-high frequency ultraviolet ultraviolet-visible visual display unit vacuum ultraviolet wavelength dispersive X-ray fluorescence X-ray fluorescence Commonly Used Symbols 4 relative atomic mass Mr relative molecular mass r correlation coefficient S standard deviation Sr relative standard deviation Journal of Analytical Atomic Spectrometry November 1996 Vol.11Ramon M. Barnes Editor Department of Chemistry 701 LGRC Tower University of Massachusetts Box 3451 0 Amherst Massachusetts 01003-451 0 USA Telephone (41 3) 545-2294 fax (41 3) 545-3757 Objective The ICP INFORMATlON NEWSLETTER is a monthly journal published by the Plasma Research Group at the University of Massachusetts and is devoted exclusively to the rapid and impartial dissemination of news and literature information related to the development and appli- cations of plasma sources for spectrochemical analysis. Background ICP stands for inductively coupled plasma discharge which during the past 20 years has become the leading spectrochemical excitation source for atomic emission spectroscopy and ion source for inorganic mass spec- trometry. The popularity of this source and the need to collect in a single literature reference all of the pertinent data on ICP stimulated the publication of the ICP INFOR- MA TlON NEWSLETTER in 1975.Other plasma sources such as microwave induced plasmas direct current plasma jets and glow discharges also are included in the scope of the ICP lNFORMATlON NEWSLETTER. Scope As the only authoritative monthly journal of its type the ICP lNFORMA TlON NEWSLETTER is read in more than 40 countries by scientists actively applying or planning to use the ICP or other types of plasma spectroscopy.For the novice in the field the ICP lNFORMATION NEWS- LETTER provides a concise and systematic source of information and background material needed for the selec- tion of instrumentation or the development of new method- ology. For the experienced scientist it offers a single- source reference to current developments and literature. Editorial The ICP INFORMATION NEWSLETTER is edited by Dr. Ramon M. Barnes Professor of Chemistry University of Massachusetts at Amherst with the assistance of a 20- member Board of National Correspondents composed of leading plasma spectroscopists. The Board members from around the world report news viewpoints and developments. Dr. Barnes has been conducting plasma research on ICP and other discharges since 1968. He also serves as chairman of the Winter Conference on Plasma Spectrochemistry sponsored by the ICPINFOR- MATION NEWSLETTER.Regular Features Original submitted and invited research articles by ICP Complete bibliography of all major ICP publications. Abstracts of all ICP papers presented at major US and First-hand accounts of world-wide ICP developments. Special reports on dcp microwave glow discharge and Calendar and advanced programs of plasma meetings. Technical translations and reprints of critical foreign- Critical reviews of plasma-related books. Conference Activities The ICP lNFORMATlON NEWSLETTER has sponsored nine international meetings on developments in atomic plasma spectrochemical analysis since 1 980 in Orlando Fort Lauderdale San Diego San Juan St. Petersburg and Kailua-Kona.Meeting proceedings have appeared as Developments in Atomic Plasma Spectrochemical Analysis (Wiley) Plasma Spectrochemistry and Plasma Spectrochemistry Il-IV (Pergamon Press) as well as in special issues of Spectrochimica Acta Part B and Journal of Analytical Atomic Spectrometry. The 1998 Winter Con- ference will be held January 5-10 1998. Subscription Information Subscriptions are available for 12 issues on either an annual or volume basis. The first issue of each volume begins in June and the last issue is published in May. For example Volume 22 runs from June 1996 through May 1997. Back issues beginning with Volume 1 May 1975 also are available. To begin a subscription complete the form below and submit it with prepayment or purchase information. For additional information please call (41 3) 545-2294 fax (413) 545-3757 or contact the Editor.Credit cards are accepted. ISSN 0767-6957 and plasma experts. international meetings. other plasmas. language ICP papers. To order complete this section and send it to ICP lnformation Newsletter %Dr. Ramon M. Barnes Department of Chemistry LGRC Tower University of Massachusetts Box 3451 0 Amherst MA 01003-4510 USA. Start a subscription for the following issue D Volume(s)- (June 19- - May 1 9-) or 0 1 9 (January - December). Enclosed Prepayment 0 Check or money order OVISA O Mastercard Account No. (All 13 or 16 digits) 3 Purchase order (No. ) or c3 Send invoice. Date Cardholder Name Expiration date Cardholder Signature Amount Due $ Mail to Name Organization Address City S ta te/Co u n t ry ZIP/Postal code Telephone Telex/f ax e-mail Note For each credit-card transaction a 4.26% service charge will be added reflecting our bank charges. Current subscription rates are $65 (North America) $89 (Europe South America) or $99 (Africa Asia Indian/ Pacific Ocean Areas Middle East and Russia). Back issue rates available on request. All payments should be made with US dollars by draft on a US bank by international money order or by credit card. Foreign bank checks we not accepted.

ISSN:0267-9477    

DOI:10.1039/JA996110X049

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

Thermally Stabilized Iridium on an Integrated Carbide-coated Platform as a Permanent Modifier for Hydride-forming Elements ih Electrothermal Atomic Absorption Spectrometry. Part 3. Effect of L-Cysteine Dimiter L. Tsalev Alessandro D’Ulivo Leonard0 Lampugnani Marco Di Marco Roberto Zamboni Spectrometry Vera I. Slaveykova Faramarz Rastegar Maurice J. F. Leroy Rapid Determination of Selenium in Soils and Sediments Using Slurry Sampling-Electrothermal Atomic Absorption Spectrometry lgnacio Lopez- Garcia Mateo Sanchez-Merlos Manuel Hernandez-Cordoba ERRATUM 1007 CUMULATIVE AUTHOR INDEX 1009 989 Behaviour of Various Arsenic Species in Electrothermal Atomic Absorption 997 1003 ATOMIC SPECTROMETRY UPDATES Atomic Mass Spectrometry-Jeffrey R. Bacon Jeffrey S. Crain Adam W. McMahon John G.Williams References 395R 355R Atomic Spectroscopy Group Study Bursaries The Atomic Spectroscopy Group Analytical Division RSC invites applications from UK scientists working in the field of analytical spectrometry for study bursaries. These typically will have a value not exceeding f500 and are intended to afford applicants the opportunity for professional development. Specific activities for which the study bursary might be considered include attendance at meetings workshops and seminars or support for study visits to other laboratories. Applications should include a statement of the purpose for which the bursary is sought (1 page A4) and a summary of recent work (1 page A4). The submission should be sent to Dr S. J. Hill Chairman A.S.G. Department of Environmental Sciences University of Plymouth Drake Circus Plymouth PL4 8AA at least 2 months before funds are required.Urine Selenium Determination by Electrothermal Atomic Absorption Spectrometry Influence of Urinary Phosphates on the Trimethylselenonium Ion Signal Alain Leblanc Microwave Digestion-Cold Vapour Atomic Fluorescence Spectrometry Kathryn J.Lamble Steve J. Hill Use of Multiple Emission Lines and Principal Component Regression for Quantitative Analysis in Inductively Coupled Plasma Atomic Emission Spectrometry with Charge Coupled Device Detection Daran A. Sadler David Littlejohn Characteristic and Continuous Fluorescence Correction for Electron Probe Microanalysis of Thin Coatings at Oblique Incidence H. Benhayoune Automated Large Volume Slurry Preparation in Slurry Sampling Electrothermal Atomic Absorption Spectrometry Uwe Schaffer Viliam Krivan Absorption Spectrometry F.Laborda M. T. Gomez M. S. Jimenez J. M. Mir J. R. Castillo Technique for the Introduction of Dry Atomic Vapours for Improved Optimization and Diagnostic Studies of Laser Ablation Inductively Coupled Plasma Spectrometry W. Doherty P. M. Outridge D. C. Gregoire CUMULATIVE AUTHOR INDEX 1127 1093 Determination of Mercury in Slurried Samples by Both Batch and On-line 1099 1105 1113 1 1 19 Gas-liquid Separator for Automated Hydride Generation and Atomic 1121 1123 AT0 M I C S P ECT R 0 M ET R Y U P D AT ES X-ray Fluorescence Spectrometry - Andrew T. Ellis Philip J. Potts Michael Holmes Graham L. Oliver Christina Streli Peter Wobrauschek 409R References 443R Atomic Spectroscopy Group Study Bursaries The Atomic Spectroscopy Group Analytical Division RSC invites applications from UK scientists working in the field of analytical spectrometry for study bursaries. These typically will have a value not exceeding f500 and are intended to afford applicants the opportunity for professional development. Specific activities for which the study bursary might be considered include attendance at meetings workshops and seminars or support for study visits to other laboratories. Applications should include a statement of the purpose for which the bursary is sought (1 page A4) and a summary of recent work (1 page A4). The submission should be sent to Dr S. J. Hill Chairman A.S.G. Department of Environmental Sciences University of Plymouth Drake Circus Plymouth PL4 8AA at least 2 months before funds are required.

ISSN:0267-9477    

DOI:10.1039/JA99611BX051

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

Atomic Spectrometry Update- X-ray Fluorescence Spectrometry ANDREW T. ELLIS Oxford Instruments Industrial Analysis Group 19-20 Nufield Way Abingdon Oxfordshire UK OX1 4 1 T X PHILIP J . POTTS* Department of Earth Sciences The Open University Walton Hall Milton Keynes Buckinghamshire U K MK16 9LU MICHAEL HOLMES AND GRAHAM L. OLIVER Ceram Research Queens Road Penkhull Stoke-on- Trent UK ST4 7LQ CHRISTINA STRELI AND PETER WOBRAUSCHEK Atominstitut der Osterreichischen Universitaten Schuttelstrasse 1 15 A-1 020 Wien Austria SUMMARY O F CONTENTS 1. Reviews 2. Instrumentation 2.1. General Instrumentation and Excitation Sources 2.2. Detectors 3. 3.1. Spectrum Deconvolution 3.2. Calibration and Matrix Correction Spectrum Analysis Matrix Correction and Calibration Procedures 4. X-ray Optics 4.1.Microfluorescence 4.2. Capillary Waveguides 4.3. Multilayer Focusing Devices 5. Synchrotron Radiation Sources 5.1. Synchrotron Optics 5.2. Beamlines 5.3. Geological SR Applications 5.4. Clinical and Biological SR Applications 5.5. Other SR Applications 6. Total Reflection XRF Spectrometry 6.1. TXRF Instrumentation 6.2. TXRF Applications 6.3. TXRF Surface Analysis 6.4. TXRF Related Techniques 7. Portable XRF 8. On-line XRF 9. Applications 9.1. Sample Preparation 9.2. Preconcentration Techniques 9.3. Geological 9.4. Environmental 9.5. Archaeological and Forensic 9.6. Industrial 9.7. Clinical and Biological 9.8. Thin Films 9.9. Chemical State Analysis * Review Co-ordinator to whom correspondence shou Id be addressed. Currently on study leave at the Department of Geology The Australian National University Canberra ACT 0200 Australia. Atomic Spectrometry Update This is the first ‘stand-alone’ ASU review of XRF following its ‘divorce’ from mass spectrometer techniques and it is particularly appropriate to welcome new expertise contributing to this review provided by Peter Wobrauschek and Christina Streli of the Atom Institut Vienna and Graham Oliver and Mike Holmes of Ceram Research Stoke-on-Trent.As in previous years contributions to the development of XRF continue in abundance. Also as in previous years we have chosen to highlight particular areas where developments in the technique have been or are likely to be most influential. These areas include total reflection XRF portable and on-line instrumentation developments in X-ray optics and synchrotron applications and this year contributions that cover the centenary of the discovery of X-rays.Within our experience and capabilities this review covers the most important developments in the field since last year’s review. 1. REVIEWS The centenary of the discovery of X-rays by Wilhelm Roentgen in November 1895 (the work being published early in 1896) was celebrated in several historical reviews including van de Kemenade (95/4560) and Holst (96/1180). Smith (96/27 18) celebrated the discovery by reviewing the contribution made by X-ray techniques in medicine physics materials science astronomy microscopy and in particular the impact on micro- and nano-fabrication. X-ray lithography has the potential of reaching the practical limits of the lithography process (about 20nm).However its use in the manufacture of ultra-large scale integrated devices is uncertain because UV optical- projection lithography currently satisfies commercial require- ments and future X-ray applications may lie in optoelectronics flat-panel displays and magnetic storage devices. Continuing the theme of historical perspective Quintin (96/2639) posed the question ‘Who discovered X-ray fluorescence? and having reviewed contributions from a range of early scientists gave the accolade to a French physicist Georges Sagnac who is claimed to have discovered X-ray fluorescence at the Sorbonne in Paris in December 1896 when he was 27 years old. The 1 1 th report of WPAC (96/2638) in the series on spectro- chemical methods of analysis covered terms relating to the detection of radiation in the X-ray and optical wavelength regions.Topics covered were fundamental properties of detec- tors then terms relating to thermal photo-emissive semi- conductor and spatially resolved detectors. A wry smile for the Chemical Abstracts reviewer who bemoaned the lack of coverage of the traditional photographic emulsion detectors. Several contributions covered general aspects of the X-ray Journal of Analytical Atomic Spectrometry November 1996 Vol. 1 1 (409R-442R) 409Rfluorescence technique including publication of the second edition of ‘Quantitative X-ray Spectrometry’ by Jenkins et al. (96/1118) and a conference review of trends in X-ray spectroch- emical analysis by Ellis (96/C197).Two Chinese language reviews were presented one by Chen (96/1323) and a second by Tao (95/4529) covering the contribution of XRF in a wide range of technique configurations. 0 ther general contributions included a German language review of the XRF analysis of the light elements by Holst (96/616) and a Chinese language review of rare earth element determinations by Liu et al. (95/4523) of which XRF was one of a range of techniques considered. Kato et al. (96/2777) claimed a Japanese patent for the ‘X-ray analysis method’ which from the summary details available for review sounds almost the same as the procedure already in widespread use. I wonder what Georges Sagnac would think of it. 2. INSTRUMENTATION 2.1. General Instrumentation and Excitation Sources Cicardi et al.(96/565) undertook a comprehensive theoretical and experimental investigation of a novel excitation source for the production of intense sources of monochromatic X-rays by the bombardment of pure element targets with protons and helium ions with energies in the range 10-100 MeV. Although proton excitation offers the advantage of a lower Bremm- strahlung continuum than conventional electron excitation in practice the production of an intense background due to nuclear reactions could not be avoided counterbalancing the advantage of the intense characteristic X-ray yield unless proton energies were kept below the Coulomb barrier. Thus use of 2-4 MeV beams permitted very intense X-ray sources to be obtained tunable in the range 1-100 keV by selection of an appropriate target.X-ray fluxes were reported for iron antimony and heavy metal targets that were 4-6 orders of magnitude greater then those for conventional electron exci- tation sources. Rotating anode tubes are the more conventional means of obtaining high X-ray fluxes by electron excitation and Sakurai et al. (96/442) reviewed the characteristics of an instrument designed with an 1100 mA 18 kV electron gun exciting a molybdenum anode designed for EXAFS measurements. Results for structural measurements on Cu-V alloy powder were similar to those obtained by synchrotron excitation. Kolodziejczak et al. (96/1148) described a rotating anode X-ray generator which together with an electron impact point source (with filters) and a Penning discharge source were being characterized for use with the ‘Advanced X-ray Astrophysics Facility’.Several reports of other excitation sources have been pub- lished during the current review period. Barkla polarization offers extended performance in comparison with conventional X-ray tube excitation and Heckel (96/621) demonstrated that detection limits for heavy elements in organic materials of less than 1 pg g- could be achieved on a commercial instrument. The practice of X-ray fluorescence using radioactive excitation sources was reviewed by Biran-Izak and Mantel (96/593). A Japanese patent claim for an X-ray tube was made by Kawai (96/1174) the principle innovation apparently being the use of synthetic diamond to support the heavy metal anode. Anderson and Nunn (96/494) made a patent claim for an XRF inspection apparatus in which filters are used between both X-ray tube and sample and sample and detector to optimize excitation and detection in specific applications.Gorgl et al. (96/991) used a solid state detector to measure directly the spectral distribution of X-ray tubes and reported numeric data for Cu Mo and W tubes. There is considerable interest especially in industrial labora- tories in bench top instruments and Robson and Chatelain (96/2606) reviewed recent developments in respect of new ‘multi-dispersive’ XRF instrumentation combining the benefits of both ED and WD spectrometers. Fleming et al. (95/C3038 and 96/1221) described the improvements in low atomic number performance of bench top instruments particularly in respect of the determination of Al Mg and Si in cement.Multifunctional instruments appear to be favoured in this review period with a Japanese patent claim by Toda and Kono (96/627) for an Rh-anode X-ray tube suitable for XRF and XRD measurements. Holynska et al. (96/636) described a multifunctional EDXRF instrument based on an XRD tube which permitted simultaneous measurement by TXRF X-ray microfluorescence (with a capillary waveguide) and bulk XRF analysis. This instrumentation was applied to potable water bee products and elemental mapping. The use of multilayers continues to attract considerable interest. Kanangiesser et al. (96/620) described a torroidal focusing W/Si multilayer and a planar W/Si multilayer for possible application in the EDXRF analysis of low atomic number elements.A molybdenum anode fine-focus tube was used to excite an aluminium secondary target and a monochro- matic spectrum without any background and well defined foci was observed using the torroidal multilayer. Chernov et al. (96/557) fabricated and tested an Ni/C multilayer with a grating period of 0.97 pm and a Ni/C multilayer period of 4.0nm for the diffraction of ‘hard’ X-rays. They found that diffraction efficiency and the relative intensities of different orders of diffraction depended on incident angle and reported the possibility of arranging diffracted energy into any one first order with the suppression of all multiple orders. A general theory of reflection from ‘perfect’ multilayers was described by Andronova et al. (96/556) and measurements made to compare theory with practice.Louis et al. (96/1210) reported on the characteristics of Co/C and Ni/C multilayers designed for use on the objective crystal spectrometer on the Russian Roentgen Gamma satellite. Particular interest was shown in the effect of different polishing parameters on the smoothing of the Co and Ni layers optimum performance being obtained by polishing with a 500 eV 20 mA Kr+ ion beam used for 40 s at an angle of incidence of 20”. In another Japanese patent application Haga et al. (96/1175) claimed an Ru/Si multilayer device designed as a hard-UV/soft X-ray transmission filter. Interest in X-ray lasers continued to expand during the current period and a comprehensive review was presented by Matthews (96/572) who showed that wavelengths of between 3.5 (350 eV) to 45 nm (28 eV) can now be produced routinely with bandwidths of 5 x and pulse lengths from 10 ps to many ns and described recent developments in more compact ‘table-top’ instruments.Goldstein (95/3085) reviewed the X-ray spectroscopy of laboratory plasmas including a discussion of laser-produced plasmas low density plasma sources the absorption spectroscopy of X-ray heated plasmas and ultra- short pulse laser-produced plasmas. As a further stimulus to this growing field of interest the proceedings of the Fourth International Colloquium on X-ray Lasers (1994) was pub- lished during the current review period (96/586). Fill (96/1137) also reviewed progress in the development of soft X-ray lasers including table-top sources. Although much X-ray laser work is restricted to the ‘hard UV’ region of the spectrum Rousse et al.(96/445) demonstrated the first observation of inner shell photoionization by a sub-ps laser produced plasma source. The laser was obtained from 8 keV electrons produced by a 100 fs laser operated at 3 x 1OI6 W cm-2 which excited K-shell vacancies in a Ti layer which in turn generated a 4.51 keV Ka pulse. This was used to excite Ka/KP fluorescence radiation in a calcium sample. Das Gupta (96/1126) described an X-ray laser generated in single crystals of Ni and Cu the surface of which was excited by intense X-rays of energy greater than the 41 OR Journal of Analytical Atomic Spectrometry November 1996 Vol. 11absorption edge to stimulate an intense directed beam of monochromatic Kcr X-ray photons (interestingly the authors reported that they did not observe the Kcr2 line).A Japanese patent claim was made by Kondo and Kamitaka (96,2622) for a laser-plasma X-ray source incorporating the facility to introduce a target at a pre-determined position in a vimum container without breaking the vacuum seal. Nguyen et al. (96/528) described a compact high-flux monochromatic X-ray source based on Compton backscattering between the pico- second laser and a high-brightness electron beam. Chukhovskii et al. (95/4136) used doubly bent crystal optics to prodiice an X-ray image of a plasma source. Finally Moses et al. (96/2568) developed a bench top pulsed X-ray system for measuring the scintillation properties of compounds in crystalline or powder form. The use of digital procedures for enhancing the performance of XRF instrumentation was described by several groups. Sampietro et al.(96/503) described a digital processing system designed to enhance signal to noise ratios of X-ray spectrometer measurements. The system monitored the signal from the detector and preamplifier to measure the actual noise present and so select the optimum filter to give an improved resolution (> 10%) in the energy resolution compared with analogue pulse-height analysis systems. An example of the application of the system to the energy spectrum from 241Am was presented. An ‘automatic function fitting routine’ was described in a Japanese patent application by Shioda and Watanabe (9b/630) and was designed to separate closely overlapping spectrum peaks.In another Japanese patent application Ter-ishita (96/1116) described an XRF analyser in which a background function and integration range could be stored for each specific element to facilitate the quantitative analysis of unknown samples. Quality assurance is pervading all aspects of scientific endeav- our and Warren (96/2728) described the instrumental checks required for quantitative analysis as well as the role of’ pro- ficiency testing auditing and accreditation in assuring data quality. Statham (96/2668) reviewed figures-of-meri t for determining the best values for resolution and couni rate appropriate for energy dispersive (ED) detectors used in niicro- analytical applications. The capability of achieving limits of detection of <0.loh m/m Be in berylliumsopper alloys as well as B determinations in borosilicate glasses were claimed by Toda et al.(961633) for a new commercial instrument with enhanced performance in the measurement of ‘ultra-light’ elements. Particular ;itten- tion was paid to X-ray tubes with ultra-thin end windows synthetic multilayered crystals slit designs thin windows on proportional counters and the stability and degree of vaxum systems. An interesting instrumental development was described by McDaid et a!. (96/2626) concerning instrumentation used for security screening incorporating a tantalum secondary t.irget. The instrumentation was designed for densitornetry (rather than fluorescence) measurements based on the detection of the elastic to inelastic scatter signals the ratio of which ljaries approximately as the square of the mean atomic number of the sample.By contast two papers described projectile X-ray accelerator mass spectrometry (AMS). The principle is that projectile ions (separated by the AMS instrumentation) may be identified by the characteristic X-rays they emit when slowing down in matter offering in some cases better disc rimi- nation of isobaric interferences than energy loss spectrometry. McAninch et al. (96/1242) reported X-ray yields for Fe Mo Ni Pd Se and Si ions (0.5-2 MeV u-’) and showed that yields for lighter ions approached 1 X-ray per incident ion at 2 MeV u- l. Wagner et al. (96/1240) evaluated the applications and limitations of this technique and reported that projzctile X-ray detection can only compete with conventional detection at lower energies or higher masses for which gas counters give insufficient isobar discrimination.Detection limit ratios of for 36Cl:Cl lo-* for 59Ni:Ni and lo-’ for 12?Sn:Sn were reported. Amongst other developments in the design ofinstrumentation an innovative background subtraction goniometer was described by Kansai et al. (96/2727) combining the speed of a simultaneous spectrometer with the flexibility of a sequential spectrometer. An example of an application was cited as the determination of V in stainless steel. Baryshev et al. (95/4571) showed that in the XRF analysis of impurities on a crystal surface signal-to-noise ratios could be improved if the crystal was orientated at the Bragg angle of the monochromated exciting beam.Barre et al. (96/1003) reported on the use of a convex crystal spectrometer to measure the size of an X-ray source (e.g. a high voltage discharge near tungsten and iron tips) from the measure of spectral linewidths. As ever a wide range of patent claims have been made including an XRF instrument fitted with a sample stage tilting mechanism for measuring surface contamination (96/2596) an XRF instru- ment with a reduced dead volume to shorten evacuation times (96/632) an instrument fitted with different sample masks to allow a sample to be analysed using a different mask from a standard sample (96/631) and an X-ray spectrometer fitted with four analysing crystals arranged so that the analysing X-ray beam is in line with the incoming X-ray beam (96/2724). 2.2.Detectors The most active area of research during the review period was in superconducting tunnel junction (STJ) detectors. Much of the driving force behind this research centres on the expectation of achieving energy resolution of better than 10 eV FWHM at 5.9 keV. The best resolution reported by Verhoeve et al. (96/518) was 53 eV for a 50 x 50 pm2 niobium-based device operated at 1.2 K where the X-ray source was carefully collimated in order to illuminate only the central part of the device. The energy resolution was found to degrade with increasing magnetic field. Ukibe and co-workers (96/2702) reported an energy resolution of 78 eV for an Nb/Al-AlOJNb STJ operated at 0.4 K. The measured efficiency of the detector agreed to within 30% of the theoretical efficiency. Using 5.9 keV X-rays the same workers (96/2565) measured detection efficiency which was within 20% of the theoretical value.This team also showed that X-ray signals could be disting- uished from phonons through correlation of the rise time and peak voltage of the output signal using digi- tal signal processing techniques. A group at the Lawrence Livermore National Laboratory (LLNL) presented a useful review of the characteristics and detection principles of STJ detectors (96/2688). The authors indicated that the tunnel- ling signal (charge or current) could be enhanced by using a quasi-particle trap near the tunnel barrier. Using Nb/Al devices the authors varied the energy gap in the trapping layer by changing its thickness and reported a resolution of 12 eV FWHM but at only 1 keV.The energy resolution was found to vary very little over the temperature range 100-700 mK despite concerns about the decrease in energy gap in the 50 nm thick aluminium trapping layer. A review of recent progress in STJ detector technologies (96/2715) described the use of arrays of STJ grains as the most mature technology but identified the use of colloids and arrays of superconducting dots as encouraging new technologies. A factor of two improvement in the sensitivity of the readout system was also reported. Azgui and co-workers (96/2686) described an Ag/A1203 STJ of 1.5 x lo4 pm2 area and 100nm thickness providing energy resolution of only 250 eV at 80 mK. The major reason for this disappointing resolution was attributed to the large effect of position of detection on detector response.Clear evidence for Jourital of Analytical Atomic Spectrometry November 1996 Vol. 11 41 1 Rdifferences in detector response over distances of less than 10 pm across an STJ was found by using a 'cryo-scanner' comprising a highly collimated X-ray source mounted on a cryogenic X-Y stage (96/2714). Edge effects in Nb/A1 STJ detectors were also reported (96/439) where quasi-particle loss due to trapping in the anodized edges of the junction caused a degradation in energy resolution. Quasi-particle trapping was also achieved using an NbN layer in Nb/A1 devices (96/2671 and 96/2589) which led to a valuable enhance- ment of the collected charge. An early device of this type with an area of 50x 50pm2 exhibited energy resolution of only 300 eV at 5.9 keV (96/2685).Fabrication details and electrical characteristics of a niobium-based STJ with an A1 trap were presented by Blamire et al. (96/2710). These authors observed an appreciable rise in sub-gap current at a voltage equal to one third of the total gap voltage. Initial electrical measure- ments on what for Nb/A1 STJ detectors are large devices of 200 x 200 pm2 area were reported by Joosse et al. (96/2701). The X-ray detection characteristics of an Nb/A1 STJ detector were studied over the energy range 4-15 keV using SR (96/2703) and the cross-sectional micro-structure of the Nb/A1 junction itself was investigated using transmission electron microscopy (96/27 13). Tantalum-containing STJ detectors were proposed by Netel et al.(96/2683) in order to increase detection efficiency at higher energies. A 10pm Ta layer was proposed although initial fabrication work involved only aluminium layers. A high-2 absorbing crystal was also proposed by Erd et al. (96/2687) to increase detection efficiency which was studied over the 1-22 keV energy range. This type of device was also expected to provide some spatial information. Junctions based on Nb/Ta (96/2682 96/2708 96/1218) and on Ta/W/AlO,-Al/Ta/Nb (96/2592) were also fabricated and stud- ied. Two groups (96/2675 and 96/2676) participated in a polemic relating to the size of the band gap and operating temperature and bias in experiments with Nb/Al-AlO,/Ta/Nb junctions. A patent claim was made (96/2580) for Nb/Ta STJ detector utilizing a cubic crystal of Ta and for which heat cycle resistance and energy resolution were claimed to be improved.Non-linearity in the energy response of niobium based STJ detectors was studied in the energy range 0.15-6.5 keV using both a monochromatized SR and an ''Fe radioisotope source (96/2697). The non-linearity was found to depend on the size of the device and on the thickness of the electrode in which photon absorption took place. The explanation of these observations was based upon a model involving self- recombination of quasi-particles. These studies also revealed a dependence of energy resolution on variations in spatial response of the device. Quasi-particle loss and energy non- linearity was also studied by Goldie et al. (96/2712) who found that 'thick' devices had a linear response whilst 'thin' ones did not and that non-linearity was not a function of device area.Conversely two groups in Naples Italy reported (and on the basis of their calculations expected) a linear response with energy in niobium-based STJ detectors (96/2704 and 96/2707). Computer modelling of STJ detector mechanisms is increas- ingly important as a means of identifying designs which can overcome some of the limitations of present devices. Rippert et al. (96/465) studied several mechanisms including quasi- particle trapping and self-trapping and loss of hot or cold excitons in order to explain the poor energy resolution being reported for present-day devices. Based on their model calculations the authors proposed a design based on a I-dimensional super-lattice of STJs which was expected to alleviate many of the effects which led to degraded energy resolution.A group at LLNL modelled the decay of the STJ output current pulse from collection of the >lo6 charge carriers deposited by the incident X-ray photon energy (96/469). The most successful model took into account trapping of quasi-particles in detector junction materials and self- recombination of generated quasi-particles. The authors also found a small variation in pulse shape depending on which layer of the tunnel junction absorbed the X-ray. A method for designing the parameters of STJs and predicting their perform- ance as X-ray detectors was proposed by Ishibashi and co-workers (96/2591). Interest has also been high during the review period in detectors based on cadmium telluride and cadmium zinc tellu- ride.An extensive review of the properties of cadmium zinc telluride and its use was presented by James and colleagues (96/2679). Recent progress in detectors fabricated from cad- mium telluride including work on signal processing improve- ments was reviewed by Siffert (96/513). The performance of a cooled cadmium zinc telluride X-ray detector was reported by Niemela and Sipila (96/457 and 96/2673). Cooling of the detector to - 30 "C reduced leakage current to the picoamp region and allowed these authors to use pulsed optical charge restoration and longer amplifier shaping times. As a result energy resolutions of 240 eV (FWHM at 5.9 keV) at -40 "C and 282eV at -30°C were obtained which the authors correctly claimed to be comparable to those obtained for Peltier-cooled mercury(11) iodide detectors.The higher bias at which the cooled detector could be operated both improved the P/B ratio and reduced peak tailing due to incomplete charge collection. An investigation into why cadmium telluride crystals grown by the travelling heater method gave good properties as X-ray detectors while those which were undoped and grown by the Bridgman furnace method did not was carried out by Steer et al. (96/470). The effects of doping with C1 V or Zn on the Bridgman crystals was also investigated. An interesting detector comprising an array of cadmium telluride detector elements grown by molecular beam epitaxy on an Si( 100) substrate was described by Yo0 and co-workers (96/612).Spatial resolution of the array detectors was 75 pm using a 50 pm SR beam and the device had a linear response up to 15 keV. Sato and colleagues (96/1173) reported radiation- induced polarization effects observed as a progressive decrease in the detected count rate with increasing charge deposited in cadmium telluride detectors made from crystals doped with indium or gallium. Crystals doped with chlorine gave detectors which showed no such deterioration. The same group observed a similar effect with a detector array comprising crystals of 500 x 500 pm2 area which had been doped with indium and grown by the vertical Bridgman technique (96/2680). Finally Eissler and Lynn (96/2695) reported the use of zinc selenide crystals grown by the high pressure Bridgman technique in detectors measuring 10 x 10 x 2 mm3.Turning to more conventional energy dispersive semiconductor detectors Lowe (96/2700) reviewed the design of silicon and germanium detectors for use in X-ray microanalysis and McCarthy (96/2699) reviewed progress in reducing the effects of dead layer in the detection of light element X-rays in semiconductor detectors. Non-linearity in energy response of an Si(Li) detector around the Si K absorption edge was investigated in a careful study by Torii and colleagues (96/629). The apparent non-linearity in energy response was attributed to a charge diffusion process in silicon and the authors proposed a detector response function which accounted for this effect. On the basis of the model the authors suggested that there would be no such effect in detectors using front- illuminated charge-coupled devices (CCD).An impressive new Si(Li) detector was reported by Rossington and colleagues (96/558). This large area (200 mm2) detector was designed to have low capacitance and was coupled to a special low noise JFET preamplifier. An impressive energy resolution of 220 eV (FWHM at 5.9 keV) at a throughput of 145 counts s-l using 41 2R Journal of Analytical Atomic Spectrometry November 1996 Vol. 11a 1 ps amplifier shaping time was obtained. A model for the Si(Li) detector response function was described by Joy (96/2690) which accounted for incomplete charge collection effects. Newbury (96/2628) provided a timely reminder of the artifacts observed in energy dispersive X-ray spectrometers used in electron beam instruments.A model which generated a spectrum from first principles was claimed to be a powerful tool for assessing the impact of artifacts on qualitative and quantitative analysis although most of the odd artifacts described are routinely compensated. in many contemporary software packages used for EDXRF analysis. A comprehensive review of germanium detectors was pre- sented by Sareen (96/2692) and Audet et al. (96/2709) reviewed the over-all benefits and history of high purity germanium detectors for use in ED microanalysis systems. The latter authors also included a section on recent advances in the new digital signal processing systems. Improvements in spectral background caused by a decrease in incomplete charge collec- tion when amorphous germanium was used as the,front detector contact in place of either palladium or implanted boron ions were reported by Luke and colleagues (96/437).Operation of this new type of detector at higher bias eliminated completely one of the incomplete charge collection effects and yielded spectral backgrounds which were claimed to compare favourably with conventional Si( Li) detectors. Johnson and Burns (96/456) compared the Monte Carlo calculated efficiency of a high purity germanium detector with that deterrnined using a novel experimental method based upon a numher of radioisotope sources. The use of Monte Carlo modelling combined with a number of experimental measured efficiency values allowed an accurate and complete determination of detector efficiency over the range 6-25 keV. The pressure remains high from workers using the newest SR sources to deliver still further improvements in ED detector resolution and count rate.A rather spectacular detection system conipris- ing a compact array of 30 high purity germanium dete<;tors each with a digital pulse processor was described by Farrow et al. (96/508). The system was used at the Daresbury UK SR facility and yielded an order of magnitude improvement in throughput for each channel and an anticipated improvement of two orders of magnitude for the complete assembly. The wide acceptance of mercury(rl) iodide detectors in the field of EDXRF is perhaps under-recorded by the few references to them in the current review year. Bao et al. (96/2677) reviewed the properties of mercury(11) iodide including the processing needed to create X-ray detectors using this maierial.Early results of obtainable energy resolution of mercury(11) iodide detectors produced by two Chinese groups were clisap- pointing. One group reported energy resolution at room temperature of 900 eV (FWHM at 5.9 keV) albeit for a large device measuring 20 mm2 in area (96/2678) and another group reported a resolution of 1300eV. Both these sets of meFsure- ments are much worse than those previously reported by other authors over the past few years when devices with eiiergy resolution of the order of 350eV at room temperature have been demonstrated. The successful construction of a very impressive 100-element mercury(11) iodide detector arra! was reported by Patt et al.(96/1202) in which the signal processing electronics were highly miniaturized and incorporated di-ectly on to the detector array. The array was fully controlled by software and has been used for EXAFS work and is also intended for use in SRXRF experiments. Such a detector array was identified (96/2694) as the leading candidate for use in an EDXRD instrument as it offered high detection efficiency and room temperature operation. The Coimbra (Portugal) group remained active in the field of gas proportional scintillation counters (GPSC) and extended the energy range of these detectors to higher energies through the use of a xenon gas fill (96/458). By using a 25 cm diameter entrance window and a collimated 1 cm diameter incident X-ray beam an energy resolution of 4-5% was obtained over the energy range 20-60 keV.Further improvements in high energy efficiency were made by the same group (96/471) using a large volume (3 1) xenon filled detector which was also equipped with a curved grid and special focusing rings. Efficiency at 60 keV was 64% and energy resolution was 5-6%. The curved grid was also used in a further type of GPSC where it produced a radially increasing electric field and therefore a regularly increasing scintillation intensity which exactly compensated for the geometric losses which are normally observed when using these detectors with entrance windows greater than 2 cm diameter (95/3412). An energy resolution of 8% (at 5.9 keV) was obtained for a collimated 2.5 cm diameter incident X-ray beam. A description of the technology of energy dispersive detectors based on an un-doped planar silicon photodiode was given by Strueder and Soltau (96/2706).The use of large area room temperature devices in strip detectors and drift chambers was shown to have particular application when spatial information was required. A 1 mm2 planar silicon diode was coupled with a specially designed ultra-low-noise preamplifier and used in an X-ray spectrometer by Bertuccio and Pullia (96/443). Despite the small size of the device and its specially designed preamplifier its energy resolution was poor (517 eV) at room temperature (297 K) although cooling the diode to 223 K improved this figure to 288eV. A study was made by Jalas et al. (96/564 and 96/440) of silicon diode and drift detectors prepared from high purity silicon of 300 pm thickness. When cooled to - 30 "C a detector with an active area of 18 mm2 gave an energy resolution of 385 eV (FWHM at 5.9 keV).Improved energy resolution of better than 300 eV was obtained for a detector with a 1 mm2 active area. These authors attri- buted the incomplete charge collection effects observed in these devices to crystal edge effects and to properties of the ion implanted front contact. Wenzel and co-workers (96/464) reported substantial signal gain (up to a factor of 25 improve- ment) when silicon photodiode detectors fabricated from high resistivity silicon were operated at a bias voltage greater than that required for complete depletion of the silicon. In addition to the signal gain the quantum efficiency of these detectors was claimed to be 100% for photon energies up to 10 keV.Diodes made from low resistivity silicon having a low leakage current did not exhibit any signal gain. A semiconductor strip detector 6 mm long and with a pitch of 55 pm in which the 16-channel preamplifier circuitry was integrated into the same silicon wafer was fabricated by a team at Lawrence Berkeley Laboratory CA (96/438). When cooled to -5 "C an energy resolution of 350 eV (FWHM at 5.9 keV) was obtained using 2 ps preamplifier shaping time making this device an attractive proposition where high rate counting is required. A single large area silicon photodiode cooled to 13 K provided energy resolution of 1.6 keV at 60 keV when using a specially designed cooled JFET preamplifier (96/2672).A similar multi-channel silicon photodiode array detector designed primarily for EXAFS provided an energy resolution of 350eV at room temperature (96/2691 and 96/2674). When operated at -35 "C an energy resolution of 190 eV was obtained for individual pads and 230eV for the over-all detector assembly. A simple model for a silicon photodiode detector response was proposed by Anton et al. (96/1113). The presence of a dead layer some few tenths of a micrometre thick and situated below the front - surface of the detector was considered to pose severe restric- tions on the use of planar silicon photodiode arrays in X-ray tomography where theoretical detector efficiency data are particularly important . McCarthy and colleagues (96/1149) developed a simple 3-dimensional Monte Carlo model to predict the X-ray response of deep depletion front illuminated CCDs.Accuracy Jouriial of Analytical Atomic 'Spectrometry November 1996 Vol. 11 413Rof the generated spectra was shown to be good and both quantum efficiency and energy resolution could be predicted to within a few per cent. over the 500 eV-10 keV energy range studied. A patent claim (96/2717) was made for a CCD array detector for the K emission lines of elements in the atomic number range 9-23 (F-V). A novel high resolution energy dispersive electron microcalo- rirneter detector was described by Nahum and Martinis (96/591). The temperature rise of the electrons in a thin metal absorbing layer was measured from the i/V characteristics of a normal-insulated-superconductor tunnel junction and a SQUID readout device was used.An impressive energy reso- lution of 22 eV was measured using a 15 ps preamplifier time constant from a detector operated at 80 mK and having a 0.5 pm gold absorbing layer and an active area of 100 x 100 pm2. A comprehensive review was presented by Lund and col- leagues (96/2716) covering all aspects of the fabrication and properties of lead iodide energy dispersive X-ray detectors. Shah et al. (96/455) investigated noise sources in lead iodide detector systems. These authors obtained energy resolution of 500 eV (FWHM at 5.9 keV) and determined that llfnoise was the dominant noise source and was dependent upon the detector fabrication method which the authors expected to be able to improve. Lund (96/2698) also reviewed recent progress in detector entrance windows used for EDXRF analysis of the light elements.The fabrication details of high-transmission windows made from diamond-like carbon using a chemical vapour deposition (CVD) process was described by Foulon et al. (96/480) and Lui and co-workers (96/1229). The latter group were able to prepare windows from 1-4 pm thick foil which could be made up to 11 mm in diameter without the need for a support grid in the final windows produced. A diamond window made by CVD followed by etching and thinning was claimed in a patent (96/474). A hybrid window design in which a copolymer film was supported on a boron nitride grid was described by Barkan and colleagues (96/2681). This window was claimed to be substantially better for low energy trans- mission especially for C X-rays than one in which the support grid was silicon and the window itself was boron nitride which strongly absorbed C K X-rays.The fabrication and properties of polyimide and silicon nitride ultra-thin windows for gas proportional counters was investigated by Aucoin et al. (96/472). Very low gas leakage rates were measured for 1 pm polyimide windows and 1 pm thick windows made from silicon nitride using a low pressure CVD process had a leak rate below the value detectable by the authors’ sensitive equipment. Details of the fabrication (96/441) and leak testing (96/590) of large area polyimide windows with a thickness of only 250 nm in gas proportional counters were also presented by a Finnish group.Finally the projected benefits in the transfer of thin detector window technology to X-ray tube windows were presented by Whalen and Turner (96/2735). 3. SPECTRUM ANALYSIS MATRIX CORRECTION AND CALIBRATION PROCEDURES It is pleasing to report the publication of a book ‘Quantitative X-ray Fluorescence Analysis Theory and Applications’ by Lachance and Trail1 (96/1400). This volume usefully combines extensive coverage of the theoretical basis of all the quantitative models including empirical and Fundamental Parameter calcu- lation procedures with very useful practical examples which serve both to illustrate examples of appropriate applications and to facilitate a more complete understanding of the algor- ithms covered. 3.1. Spectrum Deconvolution Prior to the application of any quantitative calculation pro- cedures it is essential that accurate intensity data are available.The acquisition of such data may be a relatively straightforward process in high resolution WDXRF spectra where overlap corrections are simple and well established a fact which on the face of it seems to have eluded Shirasaki (96/614) who claimed a patent for just such a procedure. In the case of EDXRF there is almost always a need for some type of spectrum processing and Swyt (96/2633) reviewed briefly pro- cedures for multiple linear regression fitting using generated spectra. Members of the Antwerp group documented new additions and improvements to the frequently-used AXIL program for non-linear least squares fitting of ED spectra using peak and background models (96/490).Incorporated in these new improvements were an improved peak model which accounted for the non-Gaussian nature of the photopeaks and incomplete charge collection backgrounds obtained from Si( Li) detectors. Details of the .several new background models incorporated ‘into this version of AXIL were presented in a further report from this group (96/551). The best results in terms of both accuracy and robustness were obtained from a background-fitting model using a linear combination of ortho- gonal polynomials. As other studies are made of the peak shapes in spectra from Si(Li) detectors there are sure to be further improvements in the AXIL peak fitting models. The Guelph group led by Campbell continue to extend their work in this important area and published a compilation of the natural line widths of K-N7 sub-shells (96/1009) which will be invaluable for those who have recognised the importance of including this in the peak model but lacked the accurate line width data to reap the full benefit.The inclusion of Voigt functions for line shapes and of an improved background description which took into account X-ray absorption effects was shown by Antolak and co-workers (96/1213) to enhance substantially the accuracy of peak fitting in their PIXEF program. The importance of treating the peak shape from a Si(Li) detector as a Voigt function was also recognised by Stoev and Dlouhy (96/2749) in their study of the effect of discrete sampling in an MCA on EDXRF spectrum. The authors demonstrated the importance of correct MCA settings and showed that the peak should occupy as many channels as possible for optimum peak fitting.In cases where the peak occupied very few channels the authors recommended a modi- fication of the usual peak fitting model. Initial results using a new filter for the enhancement of overlapping peaks in EDXRF spectra were reported by Flores-Llamas and Yee-Madeira (96/459). The filter was based on the Fourier transform of the second derivative of a Gaussian expression and three param- eters were adjusted to optimize the fitting of strongly overlap- ping Voigt lines. A new exponential transformation procedure for unfolding two strongly overlapping lines in ED spectra was claimed by Gerasimov (96/427 and 96/517) to be both simple and rapid. This procedure could be applied to all Gaussian peaks in both XRF and gamma spectroscopy.The important factors in the use of digital filtering and least squares library spectrum fitting for the K lines of the lanthanides was reported by Smolniakov and Koltoun (96/2747). These authors recognised the importance of stability of spectrometer gain and FWHM and recommended that the reference spectra used for fitting be matched in excitation and spectrometer settings and also in count rate to the unknown spectrum. This approach resulted in the preparation of low medium and high count rate reference spectra. These authors also recognised the effect on the relative intensities of intra-line series of differences in matrix effects between reference and unknown spectra but had no real solution to the problem.A novel iterative scheme for combining spectrum processing and quantitative calculations 41 4 R Journal of Analytical Atomic Spectrometry November 1996 Vol. 11was proposed by Fernandez and Tartari (96/1005). An initial guess of composition was made and then the SHAPE program was used to calculate the EDXRF spectrum which was then compared with the unknown spectrum. This process was then iterated until convergence was achieved. In many ways this method embodies much of the fundamental parameter approach but extends it to the whole process of EDXRF data processing. Whether this approach is better than Monte Carlo techniques which attempt to achieve the same end by a different computational method remains to be seen although both methods are limited by the accuracy and completeness of the spectrum peak and background model.Iwasaki (96/2586) presented two interesting new approaches to ED spectrum processing. In the first a linear associative neural network technique was used and in the second a Bayesian deconvolution technique was adopted. In the latter case only neutron spectra were processed but the technique was claimed to be equally applicable to XRF spectra. Neural network techniques were also used by Ruisanchez et al. (96/2742) for the classification of mineral grains based only on seven lines in the ED spectrum. A 15-15-15 Kohonen cube topologq was used and its effectiveness was compared with other more classical chemometric techniques for the same classific ition. The conventional chemometric method of partial least squares (PLS) calibration was applied to the low resolution spectra obtained from proportional counters in an instrument using radioisotope excitation.The procedure was successfully applied to the determination of Fe and Sr in rocks Sn in plating solution S and ash in coal and plating thickness measurenients. One advantage of the approach was the implicit and automatic inclusion in the model of systematic factors which would be more difficult to model in a conventional scheme of spectrum processing followed by quantitative regression calculations. Gerasimov (96/1214) determined rather unsurprisingly that the ratio of the channel positions of the Ka and KP peaks in the EDXRF spectrum was approximately equal to the ratio of the energy in keV of the same peaks and used this relation- ship in an automated peak identijication procedure.Continuing their studies of expert systems for use in automated XRF spectrum interpretation systems Abbott and Adams (96/ 2743) reported the strategies by which the required expert knowledge and rule base were elicited from the human experts. A general Monte Carlo (MC) simulation program produced by members of the Antwerp group for EDXRF spectrz was extended to predict the spectrum response of instruments in which polarized radiation is used for excitation (96/566) The results from the program were verified using an SRXRF beam line which delivered polarized monochromatic radiation. A second paper by this group (96/2630) described the extension of the same MC program to the more complex case of polychromatic polarized radiation which is also available from SRXRF beam lines.The simulation was applicable t o the widest energy range (1-80 keV) expected to be available at present SRXRF sites. An MC simulation for radioisotope- excited XRF spectra collected by a Ge(Li) detector was described by Sahin et al. (96/625). Good agreement with experimental data was obtained for rather simple samples comprising pure molybdenum foils cut to different racii. A useful new tool for the calculation of X-ray tube spectra was proposed by Wilderman and co-workers (96/2629). The authors’ program used MC simulation techniques to pi edict the energy spectrum produced by X-ray tubes operated in the voltage range 20-50 kV. Details were given of the models and data sources used and experimental data for a number of interesting anode materials showed good agreement with the predicted data from the MC code.Finally an XRF simulator for use in education was described (96/512 and 96/2631) although it was limited to systems containing only 3-5 elements chosen from an over-all list of 24 available. 3.2. Calibration and Matrix Correction A comprehensive MC method was adopted by Gunicheva and colleagues (96/404) to calculate the XRF intensities from heterogeneous samples. The model included first second and even third order matrix effects scattering effects and allowed for independent specification of the particle size of the fluor- escer and matrix components. Experimental results from slurr- ies alloys and powders agreed well with those predicted by the MC model.Such a model could be a particularly valuable tool for deciding optimum sample preparation approaches and for assessing the suitability of certain industrial sample streams for on-line XRF measurement. Taking a much simpler empiri- cal approach Srivastava et al. (96/1222) investigated the effect of particle size on the analysis of a model binary system of silica and calcium carbonate powders. The particle size range studied was 20-250 pm and the authors reached the completely expectable conclusion that increasing particle size resulted in decreased Si and Ca intensity. A polynomial correlation was derived between particle size and analyte intensity which was used to simplify the analysis of these binary mixtures.The problem of inhomogeneity of sample is even more extreme in X-ray micro-fluorescence systems and the effect on analysis of both inhomogenous and irregular sample particles was investi- gated by the Chalmers group (96/2751). A quantitative method was devised based on the use of correlation graphs between the intensities from different X-ray lines. The method was capable of distinguishing chemical variations from those due only to sample topology and provided accurate analysis even for highly irregular millimetre-sized glass fragments such as those encountered in forensic analysis. The empirical calculation method in which the simple linear relations hip of In (apparent concen tra tion/anal y te concen- tration) versus In (energy) is used was investigated experimen- tally by Yap and Hua (95/3367). The relationship was shown to hold for the elements in the 2 range 25-42 (Mn-Mo) using the K fluorescence intensities in a porcelain matrix and pro- vided a very simple method for which very few calibration samples were required as interpolation from element to element was reliable.An empirical modification of the Lachance algor- ithm was proposed by Smolniakov and Koltoun (96/611) for the rapid analysis of widely varying matrix materials. Despite the loss of the theoretical traceability of the Lachance algor- ithm the author claimed the new algorithm to be applicable to an industrial mineral processing application where accuracy of 1% relative was required. Such an approach might usefully have considered retaining the theoretical rigour of the Lachance approach through the use of calculated alphas which would have also provided the wide matrix range required.Such an approach was adopted by Giles et al. (96/409) to produce a wide-range calibration for the analysis of oxides and carbonates as fusion beads. The authors used the De Jongh algorithm and made use of calculated alpha coefficients for all the 19 analytes. The calibration process required only two standards per analyte one of which was based upon a pure element or oxide diluted into a fusion bead and the other a blank or zero bead. The calculated alphas took account of the matrix effects and the two standards were used to derive the instrument sensitivity. The calibration process was very simple required a minimum of standards and was demon- strated to be as accurate as conventional calibration methods for which a large suite of calibration samples was required.A similar approach (96/2593) was adopted for the analysis of iron-rich geological materials using either the Lachance Trail1 or De Jongh algorithm. In the former case theoretical alphas were calculated using NRLXRF. A new model based on a Taylor series expansion to evaluate matrix effects in an Fe-Zr system was proposed by Adelantado et al. (96/1120) although it is unclear to this author why existing algorithms would fail Jourrd of Analytical Atomic Spectrometry November 1996 Vol. 11 41 5 Rto perform the required matrix corrections. Bosch Reig and colleagues (95/4734 96/1205) continued their work on the limit dilution method which they showed to be a reliable and fairly simple method for the elimination of matrix effects in the analysis of complex geochemical samples.The method gives rise to linear calibration plots and has no need of explicit interelement corrections although the work of Giles et al. mentioned above clearly demonstrates that the matrix effect can readily be compensated by an even simpler fusion method involving no serial dilutions of the sample. Notwithstanding the limit dilution method was demonstrated by the authors to be accurate even when the sample type (e.g. a soil) was somewhat different in matrix from the calibration samples. The benefits of the fundamental algorithm were reiterated in a review by Rousseau (96/607) the creator of the algorithm.A novel 3-dimensional graphical approach to visualising the magnitude of correction factors in empirical correction cal- culation procedures was presented by Klimasara (96/2745). Examples of Lachance-Trail and Lucas-Tooth and Price models were given and the ability to visualize the real magni- tude of a particular inter-element effect was claimed to offer a substantial benefit. The same author (96/608) also described the use of a spreadsheet for mathematical modelling of the same matrix correction procedures. This approach was claimed to offer educational benefits and to offer the opportunity of investigating the corrections without the constraints imposed by some commercial XRF instrument suppliers. An overview of the features available in Uniquant-2 a standardless XRF analysis package was presented by Boumans and Blaakmeer (96/2585). The authors gave examples of the use of this package with a sequential WDXRF spectrometer which provided data for up to 60 elements in less than 20 min.The package was used successfully with samples of fly ash kiln dust pulverized fuel ash and blast furnace slag for which calibration standards were particularly hard to acquire. Wu et al. (95/3400) described an iterative method for standardless WDXRF analysis which they applied to aluminium alloys. The method did not require a knowledge of the incident spectrum and was claimed not to be influenced by sample form. Ebel and colleagues (96/2744) provided a comprehensive description of their use of total electron yield (TEY) measure- ments to characterize copper-gold materials.The process required the collection of the photoelectrons and Auger elec- trons emitted from samples subject to X-ray irradiation from a monochromatic source. The change in TEY when a sample is irradiated with monochromatic X-rays 100 eV either side of an absorption edge gave a direct measure of the concentration of that element in the sample without the need for matrix correction. Detection limits of the order of 0.1% m/m were obtained for the Cu-Au alloys investigated. The nature of the energy distribution of the exciting X-ray beam used for XRF measurements is of great importance for a complete understanding of the XRF process and therefore for use in fundamental parameter (FP) calculations (96/609). Gorgl and co-workers (96/991) made direct ED measurements of the spectra produced by diffraction X-ray tubes using anodes made from copper molybdenum or tungsten.Their method was applicable for all types of tubes and has the benefit of producing the energy spectrum directly data which then only required a straightforward correction for the efficiency of the energy dispersive detector. An MC simulation technique was adopted by Araki et al. (96/1226) to describe the tube spectrum from solid rhodium and copper targets excited at 20 and 50 keV. Although over-all agreement with measured values was good there was some overestimation of intensity at the lowest energies. In a study carried out at TU Vienna (96/2746) the ED spectra from 13 pure metal solid targets were measured on an electron microscope operated at accelerating voltages in the 5-35 kV range.A number of models were applied to spectra but the best fits to the experimental data were obtained for a model proposed by Pochou and Pichoir. The energy distributions of the spectra generated from the incidence of 7 keV electrons on solid silver and gold targets were studied by an Indian group (96/1171) who found that the absorption effect in their 90 O take-off angle geometry caused a discrepancy of 20% between the predicted and measured spectra. Martinez and Delgado (96/1002) eliminated the need to know the exact incident spectrum distribution in a simplified method for FP analysis. Fluorescence yields from the X-ray excitation of thick samples of pure elements were used in place of the full tube spectrum and the calculated yields for thin samples were within 2% of the value determined using a prccedure which made use of the complete knowledge of the tube spectrum.The optimum excitation conditions for light element XRF analysis of the elements B C N 0 and F were investigated by Pavlinsky and Dhukanin (96/1007). The effects of X-ray tube window thickness and applied voltage were fairly predictable but the additional contribution to the XRF signal from photo and Auger electron excitation was shown to be considerable and is an important factor to remember in light element analysis. Finally Pillay and Peisach (96/989) presented a preliminary report on what they described as charge induced X-ray emission. This novel effect was observed in highly compacted solid metal fluorides subjected to bombardment with an ion beam.The excessively high X-ray signal obtained by such excitation was attributed to the generation of a high potential on the sample surface which when the breakdown voltage of the material was exceeded caused an internal flux of high energy electrons which resulted in X-ray fluorescence. The incident beam was only imparting electrical charge to the sample the ions were insufficiently energetic to generate X-rays as in conventional PIXE experiments. This year is no different from previous years in the quantity and diversity of fundamental parameter data published. The KP Kcc intensity ratios for pure element samples of Co Cr Cu Fe Mn Ni Se Ti Zn and Zr were reported by Sahin et al. (96/1227) while Padhi and Dhal (96/1172) reported KP Kcc intensity ratios for Co Cu Fe Mo Ni Pd Rh and Ru in aluminides.In the latter study chemical effects on the ratios were observed the largest being for Co and the reasons for these deviations were explained. The K intensity ratios of elements in the 2 range 79-82 (Au-Pb) (96/552) and of elements in the Z range 14-92 (Si-U) (96/573) were reported in two further studies. In the second case a comparison of the experimental data with the available parameterizations was made. Sanchez and Rubio (96/1435) considered the effect on XRF equations resulting from double photoionization of the K shell. The authors proposed a modification to the emission factor normally included in FP calculations and indicated the effect that this process had on the absorption edge jump ratio.Cross section data were reported for the L series of elements in the 2 range 62-70 (Sm-Yb) for excitation by 15.2 17.8 23.62 and 24.68 keV X-ray excitation (96/1000); L series of Au Pb and Ta excited by 59.54 keV X-rays (96/2754); K and L series of elements in the 2 range 13-92 (Al-U) and 35-92 ( Br-U) respectively (96/2755) excited by incident photons in the energy range 1-200keV; L series of elements in the 2 range 57-92 (La-U) (95/2297) excited by incident photons at 13 discrete energies in the range 8-50 keV; M series of elements in the 2 range 78-82 (Pt-Pb) (96/1143) excited by 6.47 and 7.57 keV photons; M series of Au Pb Th and U excited by 59.57 keV photons (96/983); L series of Au and Pb excited by 21.56 31.64 and 34.17 keV photons (96/605); L series of elements in the Z range 64-82 (Gd-Pb) excited by 35.86 and 39.9 keV photons (96/515); and L series lines in the energy range 10-20 keV excited using 3 different radioisotopes (96/460).A compilation of fundamental parameters was pro- duced by Schoenfeld and Janssen (96/2753) and Sanchez et al. 41 6 R Journal of Analytical Atomic Spectrometry November 1996 Vol. 11(96/996) used highly monochromatized SR to measure the L sub-shell Coster-Kronig and fluorescence yields for Tb Mass attenuation coefficients for 12 moderate to high Z elements were measured using 5 photon energies available from an 241Am radioisotope source (96/516). Deviations of > 1090 from predicted values were observed for Ta at 17.8 and 26.3 keV and for W at 59.5 keV.The latter deviation was in agreement with the experimental work of others. Szaloki (96/2752) devel- oped a useful empirical relationship for the atomic form factor and incoherent scattering functions for all elements in the 2 range 1-100. The calculated values showed good agreement with the data in the Hubbell tabulation. Finally Stoev and Dlouhy (96/575) described a computerized XRF spectroscopy database which contained many valuable fundamental param- eters for all elements in the Periodic Table. Scatter correction procedures remain ever-popular and aidely employed in XRF spectrometry. Tartari and co-workers (96/992) made an interesting extension to the usual techniques of scatter correction. In their work the Rayleigh (coherent scatter) peak was of such low intensity that the traditional Rayleigh Compton ratio method of determining light element composition of the sample matrix was unusable. Such spectra were usually obtained for in uiuo XRF measurements of bone lead where only small X-ray exposures were allowed arid the Rayleigh peak was indistinguishable in the resulting spectra.Despite this the authors were able to use the shape of the intense Compton peak to calculate the light element content and therefore to correct the Pb signal for matrix effects in the sample types studied. A useful comparison was made (96/994) in trace element determination in mosses of the features of both the usual Rayleigh Compton scatter intensity ratio pro- cedure for light element estimation and thereby sample mass absorption correction and the emission-transmission technique in which the mass absorption coefficients of the matrix are determined directly.The additional K series intensity from lanthanide elements generated by the scattered radiation resulting from interaction with the light element fraction of the sample was investigated by Smolniakov (96/2750). Calculated intensities showed several per cent. enhancements owing to the scattered radiation excitation and agreed well with observed data for excitation using radioisotope sources emitting 59.4 or 88 keV X-rays. Rao et al. (96/993) measured coherent and Compton scatter cross sections for 42.75 and 47.24 keV X-rays in thick samples of Al Au Cu Mo Pb and Y. The measured coherent cross sections were higher than the theoretical values which the authors attributed to resonance effects fine structure effects and oscillation of coherent intensity around the absorption edges.Conversely the measured Compton cross sections were lower than expected for the heavy element targets. Fernandez (96/1006) presented a comprehensive review of the polarization eflects encountered in XRF spectrometry. The author stressed the importance of degree and type of polariz- ation on scattered X-ray intensities and noted that theie was a need for additional corrections when using the scattered radiation for quantitative analysis. 4. X-RAY OPTICS 4.1. Microfluorescence There is a continuing and healthy interest in the development of X-ray microfluorescence techniques and an interesting :-euiew by Bilderback and Thiel (96/497) summarized the categories of grazing incidence optics for microbeam generation as ( i ) ellipsoidal mirror (ii) Wolter mirror (iii) monocapillary con- centrator (iv) microchannel array and (u) polycapillary concen- trator and summarized the characteristics of each.Despite the many sophisticated means of actively focusing X-ray beams it must not be forgotten that it is still possible to undertake microfluorescence simply by collimating the beam from an X-ray tube though with some restriction on beam resolution. In this context Lu et al. (96/1206) described the assay of precious metals in jewellery using a low-power X-ray tube as excitation source coupled to a 0.1-5 mm diameter collimator. The sample placed on a three-dimensional stage was aligned with an optical microscope and fluorescence radiation detected using a proportional counter giving analyt- ical precisions in the determination of gold of 0.1%.An equivalent instrument is now available from a commercial manufacturer. A similar commercially available instrument was described by Gurvich (95/2533) designed with a micro- spot low power X-ray tube (50 kV 1 mA) again with colli- mated optics close coupled to a Si(Li) detector. This instru- mentation was designed for a range of applications including the semiconductor industry forensic science metallurgy and geology. As an alternative to simple collimation Beckhoff et al. (96/1122) described a microfocus EDXRF instrument that used toroidally shaped highly orientated pyrolytic graphite specifically designed to focus the 17.441 keV Mo Kor tube line at a Bragg angle of 6.071'.The focal spot area had a diameter of about 1 mm (FWHM) and the diffracting crystal was arranged to view the fine focus Mo X-ray tube at a take-off angle of 6'. Various shapes of toroids (including Johansson type crystals) were tested based on extended Monte Carlo simulations to optimize focusing and Bragg reflection proper- ties. The analysis of particulate matter collected on thin films (including aerosol filters) was proposed as an application of this instrumentation. Microfluorescence applications included Smagunov et al. (95/2886) who studied microstructures in steel samples using an instrument fitted with a high power rhodium anode tube. In a series of publications Lankosz and Pella developed correction procedures appropriate in various microfluorescence applications.Measurements were made on the NIST micro- fluorescence instrument using an Mo anode microfocus X-ray tube collimated to a diameter of 177 pm. They developed a fundamental parameters method (96/1010) for the microanal- ysis of flat optically polished geological specimens using the ratio of coherent to incoherent scatter to calculate average atomic number and mass thickness of the sample. The spectral distribution from the tube was calculated from a published algorithm. The correction procedure accounted for hydrogen and oxygen (elements that could not be measured by XRF) and was applied to samples of known composition that were both infinitely thick and of intermediate thickness.This model was then developed and applied to the quantitative analysis of individual particulate samples from 50 to 160 vm in size (96/1011 95/4667). Fluorescence X-ray intensities were cor- rected for particulate size by comparing the projected area of the particle with the known size of the collimated excitation beam. Again the ratio of coherent to incoherent scatter was used to calculate average atomic number of the sample with mass thickness estimated from the intensity of incoherent scatter. This correction model together with one usually applied to flat samples of intermediate thickness were evalu- ated in the analysis of homogeneous glass particles of known composition and size. It was found that the main source of imprecision in measurements was the uncertainty in the optical measurement of the dimensions of the analysed particle and that for an irregularly shaped particle relative errors could be reduced considerably by rotating the particle during analysis.4.2. Capillary Waveguides Much topical interest continues in the use of glass capillaries as X-ray waveguides whereby an X-ray beam is formed and transmitted by total internal reflection off the inner walls of Journal of Analytical Atomic Spectrometry November 1996 Vol. 11 41 7 Rthe capillary. There is a trend to call these devices capillary concentrators and to distinguish between the use of single glass capillaries (monocapillary concentrators) and many capil- laries as in the ‘Kumakhov lens’ orientation (polycapillary concentrators). Dozier et al.(96/579) considered the selection of capillaries for X-ray analysis including capillary diameter length source size and location the effect of curvature and tapering and the use of capillary bundles. There have been several interesting ray tracing studies of these devices designed to elucidate their transmission charac- teristics. The Antwerp (Adams Janssens and Vincze) and Chalmers University (Rindby) groups have made an important contribution describing the results of their ray-tracing code for capillary optics (96/529,95/4665). Their code involved numeri- cally defined capillary shapes and was able to model distortions in the shape of the capillary including bending. The code was used to optimize the beam transmission properties of conical capillaries assuming an extended X-ray source and of ellip- soidal devices using an experimentally determined capillary profile.This code was also used (95/4666 96/577) to show that when tapered capillaries are used to concentrate synchro- tron beams the much lower transmission efficiencies when compared with predicted values can be explained by bending of the capillary a deviation of 2 pm being sufficient to absorb most of the transmitted flux in the last cm of a 100-1 pm tapered capillary that was 50 cm long. Cargill et al. (96/2621) described ray tracing simulations and experiments with both straight and tapered capillaries for 5-25 keV X-rays including the effects on the exit pattern of X-rays of tilting the capillaries. Simulation was used to study the effect of source-to-capillary distance and of source size on the transmitted X-ray flux.Balaic et al. (95/4663) discussed the theory and practice of tapered capillary optics and presented a graph showing the optimum taper for a 1 pm exit diameter conical capillary as a function of entrance diameter and length for use in synchrotron applications. Dudchik et al. (96/530) in a Russian language contribution studied the propagation of X-rays in planar waveguides. Several of these ray tracing studies have demonstrated the important influence that surface irregularities can have of the transmission characteristics of capillary waveguides. York (95/4662) considered the technology offabricating glass capillar- ies particularly the precise temperature control of furnaces used to pull capillaries to shape.Brewe et al. (96/2612) described the fabrication and performance of tapered capillaries with inlet diameters of 2 150 pm and outlet diameters of d 1pm using glass fibre production techniques. Initial results indicated that the capability exists for the production of convex profiles necessary for optimal transmission. Several reports described capillary microfluorescence instru- ments and their application. Carpenter et al. (96/635) described the analytical characteristics of their high resolution instrument used for elemental imaging. The cylindrical glass capillary was placed near the focal point of a demountable microfocus X-ray tube and gave sensitivities of < 1 to 7 counts s-lpg-’. Elemental images were acquired in acquisition times ranging from 10 min to 15 h.The Chalmers University group (96/491) descibed an improved instrument incorporating a 7.5 pm ellip- soidal glass capillary and measured X-ray beam profiles detection limits and spatial resolution when used in the scan- ning mode. Conical and ellipsoidal capillaries coupled to a rotating anode source were used by a combined Antwerp Chalmers contribution (96/C179). In a second contribution Dudchik et al. (96/1144) discussed the advantages of a new X-ray tube unit having a ‘super smooth’ anode surface and a built-in waveguide collimator. The Kumakhov lens increasingly referred to as a polycapil- lary lens has attracted continued interest. Qi-Fan and Ning (95/4664) considered the capabilities of tapered multicapillary optics for X-ray focusing and described ray tracing results that showed that designs in which the curvature increased towards the focusing end provided the best transmission characteristics. Results indicated that use of polycapillary focusing optics was likely to increase microfluorescence X-ray fluxes by orders of magnitude in comparison with a current commercial instru- ment.Rath et al. (96/436) described a novel automated system to measure the X-ray transmission through glass polycapillaries reproducible to within half a per cent. and also measured the effects of intense X-ray radiation on borosilicate glass polycap- illaries and found that degradation in X-ray transmission at room temperature to high fluxes (>1.4 MJ cm-2) could be reversed by low temperature annealing (96/1141).Yan et al. (96/462) described a ‘new X-ray lens composed of guiding capillaries’ and presented preliminary results in its use for XRF and X-ray lithography (see also co-publications 96/46 1 and 96/580). The possibility of combining microdiflraction and microfluo- rescence measurements was described by Carpenter et al. (96/2736) in connection with the analysis of lead oxychloride phases (which affect the volatilization of lead from waste sites) and MgO cements (used to stabilize sludge in industrial waste water treatment plants). Tissot et al. (95/4668) evaluated similar measurements using an instrument based on a commer- cial 12 kW rotating copper anode XRD tube fitted with 30 and 100 pm glass capillary collimators to characterize a sample of solder. 4.3. Multilayer Focusing Devices Although originally valued for the diffraction of characteristic X-rays of low atomic elements (as an alternative to stearate crystals for example) multilayers are finding increasing appli- cation as focusing elements in microfluorescence instrumentation particularly for use on synchrotron beam lines.In this appli- cation Witteles et al. (96/1146) discussed the use of multilayer coated reflectors as an alternative to devices that depend on total external reflection for ‘hard’ X-ray optics. Conventional vacuum deposition cannot achieve the required specification for the 10 A layers required in such applications and the authors described a new deposition process which did not involve the use of vacuum was performed at relatively low temperature could be scaled up to large and curved surface areas and resulted in ultra-thin ultra-smooth uniform high density films with sharp interfaces.This process was suitable for iridium and osmium high melting-point metals that could not be deposited by evaporative processes. Multilayer reflectors for use as broad-band reflectors for the 15-100 keV range were also discussed by Joensen et al. (96/1117) specifically W/Si and Ni/C devices with 10-70°/~ reflectivity with a broad band pass. Relevant applications included focusing and imaging instrumentation for astrophysics as well as collimating and focusing devices for synchrotron beam lines. In a second contribution Joensen et al. (96/2738) considered the benefit of a gradual change in the layer thickness down through the structure for multilayers used as grazing incidence ‘super’ mirrors.When account was taken of imperfect layer thicknesses and absorption in overlying layers a multilayer in which the bilayer thickness was given by a power law expression was found to provide the best solution. Knoth et al. (96/2620) claimed a patent on the use of a pair of multilayer mirrors positioned between sample and detector acting as a sharp band-pass filter in which the energy transmitted was controlled by adjusting the angle of the mirrors and the separation between them. Turning now to the fabrication of multilayer devices Hoghoj et al. (96/1115) described a ‘distributed electron cyclotron resonance’ method to excite the argon plasma for depositing W/Si multilayers for X-ray optics.The plasma characteristics 41 8 R Journal of Analytical Atomic Spectrometry November 1996 Vol. 11were characterized by a Langmuir probe and as an example data were presented for a W/Si multilayer with a period of 3.0 nm and an interface roughness of <0.47 nm. A more conventional electron beam evaporator was used by 1,odha et al. (96/463) to fabricate Pt/C multilayer reflectors with 2d spacings of between 5 and 10nm for soft X-ray optics (0.8-8 keV). Results showed that Pt/C multilayers with 10-20 layer pairs exhibited high and stable soft X-ray reflectivity and that the interfacial roughness (in the range 0.5 nm) became lower for structures deposited at liquid nitrogen temperatures. Coating these reflectors with a 10nm layer of platinum increased the grazing angle reflectivity without significantly lowering the Bragg peak reflectivity.Erko et al. (96/2616) studied W/Si multilayer mirrors with 50 bilayers of different thicknesses designed for use on a synchrotron beam line which showed a smooth reflectivity of <32% at 5-22 keV at a grazing incidence angle of 0.32'. 5. SYNCHROTRON RADIATION SOURCES 5.1. Synchrotron Optics Various aspects of the performance and characteristics of multilayers used in synchrotron beam line optics were considered in several papers including Chevallier et al. (96/485) who presented results for a Bragg-Fresnel multilayer lens incorpor- ated in a scanning X-ray probe beamline at the European Synchrotron Radiation Facility (ESRF). Ziegler (96/1111) and Underwood (96/2740) presented an overview of multilayers used in various optical devices in synchrotron applications.Salashchenko et al. (96/547) reviewed the use of layered synthetic nanostructures both as normal incidence imaging and dispersal optical elements in the soft X-ray range and as filters of gamma radiation for Mossbauer spectroscopy. Andronova et al. (96/555) considered the use of multilayer mirrors in double mirror monochromators (to suppress unwanted harmonics). The problem of dissipating the high heat load generated in the first optical elements in third generation synchrotron beam lines continues to attract interest and Ziegler (96/588) reviewed the use of multilayers in this application the changes in performance that can result from an increase in temperature and the steps that can be taken to minimize these effects.Marot (96/585) discussed the merits of cryogenic cooling of high heat-load optics. Oyanagi et al. (96/1212) investigated the effectiveness of various types of water channels and cooling fins in directly water-cooled silicon crystals designed for use with high power insertion devices. Measurements on the double crystal rocking curves for a Si(ll1) reflection showed that cooling efficiency of a grooved silicon crystal was improved significantly by replacing conventional semicircular water channels and cooling fins with flat ones of optimum dimen- sions. Dezoret et al. (96/1147) described an alternative approach for use with a narrow silicon mono-crystal mounted on a cooled beryllium support. A system of piezo-electric devices was used to correct for crystal deformations caused by the synchrotron radiation.Freund (96/587) reviewed the per- formance of diamond single crystals as the ultimate mono- chromator material for high-power synchrotron beam lines one advantage being that the bandpass and angular divergence of the monochromatic beam from a relatively thin diamond crystal was not degraded by thermal effects. In a second contribution from the same laboratory (96/426) the design of an undulator beam line based on the use of this device was discussed. Other contributions on the subject of synchrotron beamline focusing devices include the use of Bragg-Fresnel optics at the ESRF as reviewed by Snigirev (96/496) for application to microprobe and micro-imaging techniques. These devices were capable of producing sub-pm spots with 108-109 photons s-' and a photon energy bandwidth of 10-4-10-5 between 6 and 100 keV.In a second contribution Snigirev et al. (96/532) provided test results for a circular Bragg-Fresnel lens fitted to the microfocus beamline at the European Synchrotron Radiation Facility. A focal spot of 0.7 pm was obtained at a beam energy of 7.6 keV with a flux density of lo8 photons s-'. The results of experiments testing an alternative focusing parabolic pyrolytic graphite monochromator was described by Dolbnya et al. (96/554) using a beamline on the VEPP-3 synchrotron. Chkhalo et al. (96/548) reviewed the status of mirror optics at this same synchrotron facility topics including grazing incidence optics multilayer mirrors and multilayer diffraction gratings.Bent mirrors in the Kirkpatrick-Baez configuration were used by Eng et al. (96/2614) to focus 4-65 keV X-rays on an NSLS bending magnet. Spot sizes of between 2.5 and 4 pm were achieved. Chang et al. (96/2615 96/1200) described a novel X-ray focusing device using crystals with two-dimensionally modulated surfaces based on both elliptically shaped and linearly modulated structures derived for both flat and cylindrically bent crystals for focusing X-rays to micrometre or sub-micrometre size. Si( 11 1) and InSb( 11 1) reflectors were used in calculations based on a wave-optics approach designed to evaluate their focusing efficiency and focus width. 5.2. Beamlines Perhaps because there are significant differences that influence performance a number of reports have been published in the current review period describing technical features of synchro- tron beamlines used for microfluorescence measurements. Bosecke et al.(96/506) described the high brilliance beam line at the European Synchrotron Radiation Facility using an undulator cryogenically cooled Si( 11 1 ) channel-cut mono- chromator and torroidal mirror. The monochromatic beam (8-16 keV) could be focused mid-range to 0.38-0.75 mm (FWHM) with a photon flux density of 2.5 x lo7 photons s-' pm-'. Kirkland and Elam (96/506) described the hard X-ray beamline being rebuilt at the US National Synchrotron Light Source. This beam line design incorporated a fixed-exit pair of mirrors for the rejection of harmonics and a fixed exit 2-crystal monochromator with sagittal focusing on the second crystal.The performance was expected to be 0.5 x 1.0 mm beam size at 2-30 keV with 5.7 x 1OI2 photons s-' per 200 mA an increase over previous designs owing to improved mirror surfaces decreased optical aberrations and increased hori- zontal beam acceptance. Tsang et al. (96/505) described the wiggler X-ray beamline at the Synchrotron Radiation Research Centre (Hsinchu Taiwan) designed to increase the usable flux of photons of energy < 15 keV. Perera et al. (96/502) described the high-brightness beamline at the US Advanced Light Source which was planned to offer a windowless beamline covering the 1-6 keV photon range. Particular features that enhanced the brightness and resolution of this facility were first matched torroidal mirrors positioned before and after the double- crystal monochromator and second a 'Cowan type' double crystal monochromator offering high mechanical precision and beam stability.A new hard X-ray microanalytical beamline proposed for the Centre for Advanced Microstructures and Devices (Baton Rouge US) was described by Petri et al. (96/2618). Planned application was for compositional and structural characterization on a microscopic scale. Synchrotron beamline experiments were undertaken by sev- eral groups including Beck et al. (96/510) for the absolute calibration of a photodiode array in the range 1.5-12 keV. These measurements were undertaken with the quartz window to the array detector removed using both the LURE Orsay synchrotron and X-ray tube excited secondary targets.Results showed that the detector had a Si active depth of 6 pm and a Journal of Analytical Atomic Spectrometry November 1996 Vol. 11 41 9RSi02 passivation layer of 5 pm. The absolute radiation flux and degree of polarization was measured by Ilinski et al. (96/500) on an undulator beam line at the Advanced Photon Source (Argonne). To avoid problems caused by the high heat load of this type of beamline a Si(Li) detector was used measure the 5-35 keV X-rays scattered from a well defined helium gas volume at a controlled pressure. Andreyashkin et al. (96/2624) described a new type of hard (10-40 keV) X-ray source obtained by passing 700 MeV electrons through a composite target (a layered structure + crystal) at the Tomsk synchrotron.Spectral densities were compared for diffracted transitions and parametric X-ray radiation by electrons. 5.3. Geological SR Applications The analysis of geological samples is one of the most productive uses of the synchrotron X-ray microprobe judging from the number of contributions available for review this year. An interesting and demanding application showing the technique to advantage is in the analysis of fluid inclusions. Building on previous publications in this area Mavrogenes et al. (96/1251) undertook an assessment of the uncertainties and limitations in the quantitative elemental analysis of individualjuid inclusions by SR-XRF. Measurements were made at the NSLS using a 8 x 12 pm white X-ray beam and calibration was undertaken against synthetic fluid inclusions containing a known amount of strontium chloride.Within a single population the mean composition was very close to the known concentrations (determined by AAS and freezing-point depression) but the precision was poor at 10-39% RSD. It was considered that errors in determining the inclusion geometry was the main cause of poor precision. The detection limit for Sr was 2000 pg g-l based on a 4-15 pm thick synthetic inclusion 5-100 pm below the upper polished surface. Glasses and minerals of geological interest were analysed by Dalphe et al. (95/4677) comparing SR-XRF using a 10 pm beam with laser ablation ICP-MS (34 pm probe). Laser ablation measurements were undertaken over a 50 x 150 pm raster to avoid specimen damage and to minimize penetration depths for individual holes.Detection limits for Rb Sr Y and Zr by SR-XRF were found to be 5.5 pg 8-l or less with an analytical precision of _+ 20% relative. Equivalent data for laser ablation ICP-MS were a < 2 pg 8-l detection limit and f 10-15O/0 precision. Both techniques were used to determine partition coefficients between titanium-rich calcic amphibole and a titanium rich basanitic quenched glass produced exper- imentally. In the analysis of glass inclusions from Vulcano in the Eolian Islands (Italy) Mosbahnet et al. (96/1181) compared both micro-PIXE and micro-SR-XRF in the study of trace elements. The SR-XRF measurements were made with an 11.8 keV 5 x 2.5 pm2 X-ray beam having a density of 2 x lo9 photons s-'. Basto et al. (95/4281) determined gold in mus- covite and lepidolite micas from Portugal using the LURE (Laboratoire pour 1'UtiIisation du Rayonnement Electromagnetique) SR facility to detection limits of a few ng g-'.The main drawback to the reliable quantitative analysis was reported to be the lack of suitable reference materials. To improve trueness and precision in the determination of Nb Rb Sr Y and Zr in the analysis ofgeochemical samples Melgunov et al. (95/4573) analysed 50mg samples of 29 reference materials using a 47 keV SR beam at the Novosibirsk synchrotron for a count time of 500 s. In some instances the certified Rb and Sr contents were used as internal standards. This same suite of elements was determined in Lunar rocks by Tarasov et al. (96/595) variations of Zr versus Sr and Y versus Zr being used to discriminate magmatic sources.Dolbnya et al. (95/4572) used SR-XRF in scanning mode to measure the base and trace element distributions in marine iron-manganese nodules from the eastern tropical Pacific and detected differ- ences in composition between surface and internal layers indicating changes in the environment in the past. An et al. (95/4569) also analysed ferromanganese nodules as well a garnet crystal their interest being in measuring elemental distributions. Sediments as accumulators of pollutants were analysed by Baryshev et al. (96/617) in an evaluation of reservoir water quality in the Novosibirsk area and by Granina et al. (96/618) in Lake Baikal. SR-XRF was used in conjunction with INAA by Mao and Chai (96/1121) to measure the homogeneities of SRM 1646 (estuarine sediment) reference material for 13 elements. Inhomogeneity effects were related to species and the mass sampled (10 pg to 10 mg).'Molecular ' environmental applications of SR-XRF were pro- posed by Brown using XAFS studies this topic being aspects of chemical speciation relevant to the toxicity bioavailability and transport of contaminants in environmental samples. The whole field of SR (analytical technology and appli- cations) applied to the characterization of geological samples was reviewed by Smith (95/4678). 5.4. Clinical and Biological SR Applications The elemental distribution of Cu Se and Zn in human kidney was determined using SR-XRF by Homma et al. (96/2558). These elements were more concentrated in the renal cortex rather than the medulla results for Cu and Zn agreeing with independent analyses by ICP-AES. Rizzo et al.(96/2619) measured the distribution of Ca S and Zn in normal and arthritic equine cartilage. Knor et al. (96/542) used SR-XRF to measure the elemental composition of insect bodies to obtain data about regional environmental conditions and migration routes particular interest being shown in the deter- mination of elemental distributions in the bodies of meadow moths from different regions and different populations. Element distributions were also measured by Thorn et al. (96/523) their interest being in the analysis of marine bivalve shells for the elements between Mn and Pb in the Periodic Table. SR-XRF permitted determinations to 1 pg g-' detection limits and 8 pm resolution. Amongst other observations their results suggested that seasonal changes in Sr concentration can be used to determine historic water temperatures.Knowles et aE. (96/1896) used a number of spectroscopic techniques to study the active site of galactose oxidase extended X-ray absorptionFne structure (EXAFS) being used to establish that oxidative activation to produce the active site by the tyrosine radical does not cause major changes in the copper coordination environment. EXAFS was also used by Strange et al. (95/3997) to study the structure of the copper site in oxidized and reduced Rhus vernicifera stellacyanin at different pH values. 5.5. Other SR Applications In the analysis of industrial samples Wheeler et al. (95/3877) applied SR-XRF to the determination of trace elements in steel elements of interest being Cr Cu Mn Mo Nb Ni Ti V and Zr. Analytical conditions were 3.9-22.6 keV monochro- matic SR beam obtained from a fixed offset Si(ll1) crystal incident at 45 O as a 1 mm2 spot.Absolute cross sections were obtained by normalization to those for NIST SRM C1173 (low alloy steel) and results were in reasonable agreement with those obtained by PIXE. Synthetic diamonds grown in a nickel based metal solvent at high temperature and pressure were analysed by Hayakawa et al. (96/1215). EXAFS was used to show that Ni atoms dissolved in diamond had a different chemical state from those in the metallic state. Larnoureux et al. (96/C844) used synchrotron X-ray absorption spec- trometry to analyse the mechanisms of palladium-induced modification of selenium.420R Journal of Analytical Atomic Spectrometry November 1996 Vol. 11Thinfilm characterization techniques based on the use of SR were used by Schmitt (96/531) to measure the centroid depths of ions implanted in various materials including phosphorus and gold on silicon TiO on alkali-free glass Cr on SiO and I diffused into polymethylmethacrylate. SR-XRF was applied to a number of chemical characteriz- ation studies. For example Lamoureux et al. (96/12741 used EXAFS to measure the speciation of Cr"' in neat solid mixtures. Dolbnya et al. (96/567) took advantage of the well determined time structure of pulses of electrons in the VEPP-3 synchrotron storage ring (Novosibirsk) to measure the pulse response time and pulse sensitivity of silicon semiconductor X-ray detectors.Time resolution was better than 0.5 ns. The chemical species formed in air-acetylene flames at temperatures above 2000 "C were studied by Nakai et al. (96/1092) using XANES. Experiments were undertaken on metal nitrate solutions intro- duced into the flame through a nebulizer and results showed that free atoms were detected for nitrate solutions of C'u and Ni but not for Rb and Sr elements of low ionization potential that may exist as ionized species in the flame. Mishra et al. (96/1001) used XANES to study seven copper(i1) mixed ligand complexes (with alanine serine valine glycylglycine and thre- onine) of importance because a number of biochemical reac- tions proceed via such complexes. Chemical shifts edge widths shifts in the absorption maximum and the structure of the K-edge were used to interpret the structure of these copper complexes.Pianetta et al. (96/C907) showed that a total reflection synchrotron XRF technique was capable of detecting 3 x 10' atoms cm-2 of Ni in silicon integrated circuit wafers in comparison with 5 x lo9 atoms cm-2 by rotating anode tech- niques. Brown et al. (96/C909) gave examples of the use of XAFS studies of Co" and Pb" sorption at alumina-water interfaces and of CrV' reduction at magnetite-water interfaces relevant to macroscopic models of uptake of environmental interest. Chemical shifts were considered by Artemiev et al. (96/550) who specifically emphasised the advantages in resolution and sensitivity offered by the use of synchrotron radiation excitation sources.Sanchez et al. (96/489) measured L-subshell Iluores- cence yields by applying the synchrotron photoionization method to foil samples of Ho Tb and Yb. SR X-ray tomography was developed by Takeda et al. (96/525) to detect non-radioactive tracers (iodine and gadolin- ium) in living objects. Instrumentation comprized a silicon( 11 1) channel cut monochromator X-ray shutter X-ray slit system and collimator a scanning table for the target organ and a germanium ED detector. A minimum of 100 ng of iodine in a sample volume of 2 mm2 could be detected. McNulty et al. (96/2625) described the potential for three-dimensional imaging to sub-micrometre resolution in the microtomography of bio- logical microelectronic and materials science samples and gave details of an instrument under construction anticipated to offer a spatial resolution of 100 nm.Various reviews considered SR instrumentation and appli- cations several emphasising the potential of third generation synchrotron sources. Smith (96/326) considered the current state of microanalysis using synchrotron X-ray techniques emphasising the importance of combined fluorescence diffrac- tion and absorption spectrometry and the possibility of follow- ing chemical reactions on a millisecond time scale. Schlachter (96/428) reviewed the capabilities of new third generation sources that produce vacuum UV and X-ray beams of unpre- cedented brightness. In a historically based review Ederer et a!. (96/429) outlined some of the recent exciting discoveries in soft XRF spectroscopy and discussed a new type of laser- synchrotron hybrid experimental technique based on the pulsed time structure of synchrotron excitation sources.Iida and Noma (96/2734) considered three types of synchrotron X-ray microbeam systems including monochromatic and continuum excitation in respect of sensitivity detection limits and appli- cation. The capability and potential for microprobe analysis using bending magnets and insertion devices including super- conducting wigglers were discussed by Sutton et al. (95/2495) and Vis (95/2494) undertook a review of the capabilities of SR-XRF compared with conventional XRF and the PIXE technique. Janssens et al. (96/2613) also compared microprobe analysis by SR-XRF with the ion and electron microprobes emphasising the complementary nature of these techniques.Other reviews included those of Hayakawa (96/2737 in Japanese) on trace element characterization using a synchro- tron radiation microprobe including the determination of impurities in high-pressure synthetic diamond Wu et al. (95/4568) who gave information on the XRF beamline capabili- ties at the Beijing Synchrotron Radiation Facility and Aberg (96/2732) on the rather more specialized aspects of radiative and radiationless resonant Raman scattering in the X-ray and UV regions using synchrotron radiation. 6. TOTAL REFLECTION XRF SPECTROMETRY 6.1. TXRF Instrumentation The most significant improvements on the instrumental side were obtained by using Synchrotron radiation as the excitation source. Pianetta's group (96/520 96/1155) undertook experi- ments at the Stanford Synchrotron Radiation Laboratory on a wiggler beamline using a double multilayer monochromator.They applied the extreme sensitivity of the method to the trace impurity analysis of semiconductor surfaces and provided detection limits of 3 x lo8 atoms cm-2 for Ni excited with 10 keV X-ray photons measured on intentionally contami- nated wafers. This was compared with detection limit results obtained using a rotating anode source of 5 x lo9 atoms cm-2. This group also discussed proposals for further improvements down to 5 x lo7 atoms cm-2. They claimed that synchrotron radiation excited TXRF will meet the projected needs of the silicon circuit industry until the year 2000. The Vienna group of Wobrauschek (96/400) performed experiments at HASYLAB Hamburg Germany using a bending magnet beamline and a single W/C multilayer monochromator.Experiments were performed on evaporated solutions with excitation energies set at 14 17.5 31 and 55 keV leading to detection limits for Sr and Cd of 20 and 150pg respectively. They also applied the technique to the surface analysis of wafer samples (96/1216). Ni was measured after deposition as a micro droplet of 1OOpg on a wafer surface simulating the VPD (vapour phase decomposition) method of sample prep- aration. Detection limits of 13 fg were obtained. This value was equivalent to 1.3 x 10' atoms ern- assuming an inspected area of 1 cm2. Arai's group described a newly developed TXRF spec- trometer (96/2793) for the analysis of semiconductor surfaces equipped with a Au rotating anode tube and a three crystal monochromator.The Au-La Au-LP and Au-Ly lines were used for excitation. Best results for W Cu and Zn were obtained using Au-Lb. Kondurov and Korotkikh from St. Petersburg (96/559) described a cut-off jilter as an improvement in a TXRF spectrometer. This cut-off was bent to the shape of a log spiral. A nickel-coated glass plate was used as reflecting surface. Detection limits were reduced by a factor of 5. The possibility of further improving sensitivity by using an additional reflector bent into a transcendental profile was discussed. Schwenke and Knoth and colleagues (96/493) described a new method for the determination of vertical concentration profiles and its application to bilayer diffusion couples using a combination of the ion-beam micro-sectioning technique and TXRF for depth profiling.Vertical concentration profiles were analysed quantitatively with a depth resolution of 2.5 nm using Journal of Analytical Atomic Spectrometry November 1996 Vol. 11 421 Rsputter sectioning and ex-situ analysis with TXRF with the advantage that no additional assumptions about sputtering rates were necessary. Streli et al. (96/1154) presented some theoretical consider- ations about the TXRF analysis of light elements under various excitation conditions. The influence of the exciting energy on background was discussed as well as possibilities of depth profiling for Ti in Si. In a further contribution (96/410) several spectral modification devices such as cut-off filters and multi- layer monochromators were compared using a Cr tube as well as synchrotron radiation as excitation sources.Peak and background conditions were compared. In a third contribution (96/600) a summary of light element analysis with synchrotron radiation was discussed. A patent was claimed by Knoth et al. (96/2570) for a new method for sample preparation in TXRF-laser induced ablation of the sample surface and TXRF analysis of the resultant plume after condensation on a carrier. A range of instrumental developments were described in other publications. Matsumura et al. (96/2799) claimed a patent for new sample reflector material a mirror-polished Si wafer coated with an acid-resistant hydrophobic optical film. This substrate should be suitable for the detection of light element impurities on semiconductor wafers.A Chinese group (96/2608) published a new double rejection system. Detection limits of 0.6 x lo-’ g and 2.2 x lo-’ g were obtained for Co and Y with Cu- and Mo-tube excitation. The group of Jin Liyun (96/2790) described the development of a new TXRF spectrometer using double total reflection as well as a new software for processing spectra. Detection limits of g were attained. The spec- trometer was specially designed for the detection of elements in insoluble residues from pressurized water reactor spent fuel elements. A patent was claimed by Arai (96/563) for an array of W/Si multilayer monochromator segments mounted on a Rowland circle wherein the segments at greater distances from the source had greater lattice spacings.Utaka et al. (96/619) designed a new TXRF spectrometer with a multilayer mono- chromator specially designed for the detection and quantifi- cation of metal contamination on the surface and near-surface region of Si wafers. Pettersson and Wobrauschek (96/399) described the use of an 18 kW rotating anode as a source for TXRF using a multilayer monochromator and applied it to the determination of gallium. 6.2. TXRF Applications Ninomiya et al. (95/4503) applied TXRF to forensic samples such as counterfeit 100 US$ bills polyvinyl tape semen drugs fingerprints and brandy. The presence or absence of certain elements was a crucial factor in distinguishing counterfeit samples. For example the presence of S in brandy resulted in its identification as a fake as no S was present in the genuine sample.Another application to forensic samples was demon- strated by Prange et al. (96/583) who analysed fibres of different textile materials such as polyester viscose and wool and identified a ‘fingerprint-type’ trace element pattern. The elements P Mn Sb and Ti were used to differentiate between several sample materials with the advantage that a very small amount of sample mass (in the sub-pg range) was required for analysis. Moens et al. (96/639) described the application of TXRF to artists’ pigments. The identification of artists’ pigments gives information for historical research and restoration and conser- vation purposes. ‘Ultra-micro’ samples of less than 1 pg were taken so the method was claimed to be practically non- destructive. One to three key elements were taken to identify the pigment.The precision of the method was reported to be 4% (RSD) for 14 replicates using intensity ratios. Aerosols were analysed by the Belgium group of Van Grieken in collaboration with Injuk (96/2791). The method was optim- ized for efficiency simplicity speed and low cost. Direct analysis of particulate matter impacted on the quartz reflectors was performed. ‘Bounce off’ effects and its influence on aerosol size distribution were investigated as well as the choice of internal standard element the effect on siliconizing the quartz disc and alternative methods of aerosol collection. Airborne particles were analysed by Klockenkamper and colleagues (95/4504) using cellulose nitrate/polycarbonate filters or using Berner- or Battelle-type impactors to collect the samples.Single filter spots were punched out placed on quartz reflectors dissolved by THF and re-precipitated prior to analysis. Using a Battelle-type impactor samples were collected directly on Plexiglas carriers coated with medical Vaseline. The best impactor material was found to be titanium and the antistatic polymer Makrolan. In a second contribution from the Klockenkamper group (96/1186) investigations were reported of suitable materials for the construction of a Battelle type impactor in order to minimize systematic errors in sampling. Blank values collection losses and memory effects were studied. Cleanroom particles deposited on a wafer were analysed by Ohsugi and Kyoto (96/C782) using a specially developed particle collection system.Other applications included an investigation of transmu- tational elements in a copper matrix by Hegedus et al. (96/1223) using monochromatized synchrotron radiation. Hockett and Metz (96/482) investigated the feasibility of using TXRF to characterize inorganic contaminants in liquid crystal display materials as a function of processing. Carvalho et al. (96/2798) studied heavy metals in Madeira wine. Pb was found in wines stored in crystal vessels (30% lead) increasing in concentration with the storage time. A comparative study of four different digestion procedures using several analytical techniques including TXRF for screening more than 50 elements in sediments of River Elbe was performed by the Geesthacht group (96/1199).The preferred method involved an HN03-HF attack followed by dissolution in HC1 after evaporation to dryness. 6.3. TXRF Surface Analysis Hockett (96/2607 and 96/1119) reviewed the analysis of wafer surfaces by TXRF with emphasis on ultratrace metal contami- nation. The author discussed future trends of this technique and also considered synchrotron radiation as alternative excitation source (96/2792) VPD-TXRF (96/1150) and TXRF in comparison with SIMS (96/2458). The increasing interest in identifying spurious peaks as observed by many scientists was reflected by a publication of Yakushiji et al. (96/1158). In particular peaks of Fe and Ni were related to trace impurities in the beryllium detector entrance window and a dependence of these peak areas on the azimuth angle was demonstrated.New standard sample preparation methods were investigated by Mori et al. silicon wafers were immersed in an intention- ally contaminated ammoniacal H202 solution (96/2766) or an alkaline H202 solution (95/1153). Good depth profile repro- ducibility and homogeneity were reported. TXRF is one of the standard techniques for characterizing the surface properties of semiconductor materials and several studies have described such applications. Using various prep- aration conditions TXRF measurements were conducted in order to monitor contamination levels of Co Fe Cr Ni and U on silicon wafers and compared with the results obtained by radiochemical analysis (96/2564). Surprisingly significant differences were reported at contamination levels close to the detection limits as well as at higher levels.With the basic assumption that only three different kinds of specimen can be used for the calibration of TXRF systems namely particulate 422 R Journal of Analytical Atomic Spectrometry November 1996 Vol. 1 Ifilm or bulk sample types Schwenke and Knoth (96/1159) described a test procedure to enable the detection of faulty calibration samples. The procedure was based on measure- ments recorded as a function of incident angle and these findings were used to evaluate the capabilities and limitations of TXRF for depth profiling. Files et al. the authors of another study (96/511) focused on the correlation of elemental con- tamination of semiconductor materials as determined by TXRF and other methods with electrical parameters and the stage of introduction of contaminants.Pahlke and colleagues summarized results from novel applications of VPD-TXRF (96/2566) and studied the quality of wafer storage boxes with regard to their cleanliness by VPD coupled to both TXRF and GFAAS (96/2571). In a Swiss study Gercken et al. (96/C2186) compared TXRF with ICP-MS and GFAAS and Tardif et al. (96/1365) compared it with VPD-AAS and VPD-ICP-MS in monitoring contamination in the manufac- ture of integrated circuits. The group working with Fan (96/2794) investigated the theoretical behaviour of Fe impurit- ies on GaAs surfaces. Files-Sesler et al. (96/553) studied thicknesses and surface contamination of InGaAs layers. Cherekdjian et al.(96/1219) used TXRF to investigate metallic impurities on the back of ion implanted silicon wafers. Sn was found to be the largest contaminant with levels as high as atomscm-’. The source of this contamination was the elastomer used on ion implantation disks to enhance wafer cooling. 6.4. TXRF Related Techniques De Bokx and Urbach (96/492) developed a laboratory grazing- emission X-ray spectrometer (GEXRF) which used in-uacuo wavelength-dispersive detection. The applicability was extended to longer wavelengths due to the suitability of crystal monochromators for the detection of low energy X-rays. Interference fringes were observed depending on the take-off angle of the fluorescent X-ray intensity of a layered sample. This spectrometer was also claimed as a patent (96/1217).Urbach and de Bokx (96/2796) developed a formularism for the calculation of X-ray fluorescence intensities for a radiating point source in a layered system without the use of the optical reciprocity theorem. The contributions of point sources at different depths were integrated. Higher order effects were considered. The derived expressions compared well with the measured angle dependence of the fluorescence intensities. Glancing incidence and take-off angle analysis (GI11 -XRF) was described by Tsuji et al. (96/477) and applied to surface analysis. The advantage of this method was explained by the restriction of the observation depth which was realized by setting the angle of the incident X-rays below the critical angle for total reflection and the take-off angle below the critical angle of the fluorescent X-rays from the element of interest.Reflection of high energy electron diffraction-total reflection angle X-ray spectroscopy ( RHEED-TRAXS) was introduced by Shozo (96/1160). By detecting the characteristic radiation excited during RHEED a highly sensitive measurement of the adsorbate was possible if the detector was placed at the critical angle corresponding to the total reflection of the X-rays. It was possible to analyse depth distributions to a depth resolution claimed to be about 1 monolayer. Total reflection PIXE was investigated by van Kan and Vis (96/986). Proton beams of 2.5 MeV and a-beams of 4.8 MeV at small incident angles (0-35 mrad) were used to itnalyse surfaces. Characteristic X-rays as well as backscattered pro- tons were detected. PIXE detection limits were investigated as a function of the angle.For angles between 4 and 20 mrad both PIXE and RBS yields dropped drastically. At angles of a few mrad the RBS yields dropped faster than the X-ray yield which was interpreted as being caused by surface channelling. 7. PORTABLE XRF The fact that portable XRF instrumentation can make measurements inaccessible to other forms of instrumentation coupled with the ever-growing awareness of environmental contamination issues means that developments in instrumen- tation and applications of this technique are likely to expand in forthcoming years. Indeed there are significantly more contributions in this category than last year including reviews of the principles and applications of ‘man-portable’ XRF by Piorek (95/2535) and the capabilities of such instrumentation for ‘quick’ chemical analyses of solid and liquid wastes (in a Spanish language review) by Cornejo et al.(96/545). In a second contribution Piorek (96/483) described portable XRF instrumentation incorporating a high resolution Si( Li) detector which allowed the implementation of more sophisti- cated data analysis procedures specifically the need to calibrate the instrument by analysing samples in the field was avoided by using a backscatter with fundamental parameters approach for the determination of heavy metal contaminants in soil. A combined XRD and XRF portable instrument was described by Kerner et al. (96/2731) designed for one of the remotest applications-planetary exploration.The excitation sources used were a 9 W Fe-anode X-ray tube (for XRD and XRF below Fe) and a shuttered lo9Cd source using both 22 and 80 keV lines to excite the higher atomic number elements. Fluorescence spectra below 6 keV were degraded owing to noise from the CCD detector used to record XRD patterns. A tube-excited instrument was described by Reeves et al. (96/383) this time incorporating a 15 W Fe-anode tube and liquid nitrogen cooled Si(Li) detector (450 eV FWHM for Mn Ka) designed for small diameter (e.g. 3.1 cm) boreholes. The instru- ment was tested in a polyethylene-lined well on a chromic acid waste landfill site where detection limits of <50 pg g-’ for 600 s count times were reported. Lavietes et al. (96/2600) described a hand-held non-cryogenic low power gamma- and X-ray measurement and analysis instrument using cadmium zinc telluride detectors.This instrument was designed for the detection and isotopic analysis of radionuclides in the field (e.g. uranium enrichment measurements) so despite not being strictly an XRF instrument (no excitation source) the detector data acquisition and analysis functions were compatible with fluorescence instruments. Judged by the number of published contributions one of the most widely used applications of portable XRF is in the analysis of heavy metal Contamination in soils (particularly lead). Swift (96/402) described a field-portable XRF instrument [ 10 mCi ‘09Cd excitation liquid nitrogen-cooled Si( Li) detection] designed to provide data for remedial activities and compared results for As and Pb with data by hydride generation and flame AAS respectively.A slight negative bias was observed in the As data possibly caused by an artefact present in the calibration modelling scheme. An application of the XRF technique to a remediation site part of which had been used to recycle lead-acid batteries was reported by Swift and Brandenburg (96,4204). Samples were collected and field scre- ened for Pb using XRF intensity data. The technique was calibrated using a selection of field samples which were ana- lysed independently by flame AAS. XRF detection limits were estimated to be 48 mg kg-’. Bernick et a/. (96/1128) also looked at the field portable XRF of a battery breakage site (for Pb) and a scrap metal site (for Pb and Zn) and reported a statistical evaluation using current US EPA quality assurance guidelines.The same laboratory also reported (96/1129 96/1191) on the application of two commercially available Journal of Analytical Atomic Spectrometry November 1996 Vol. 11 423 Rinstruments to the determination of metals in soils and sedi- ments at hazardous waste sites. Kuharic et al. (96/1130) reported on a field portable XRF programme to survey the extent of soil contamination and to evaluate the bioavailability of lead in residential soils at Leadville a historic mining and smelting area in Colorado. Aspects of sample collection prep- aration analytical procedures and database management were discussed and showed that field portable XRF could be used to provide large quantities of data of acceptable quality in a timely and cost effective manner 'when used properly'.In a second contribution Kuharic and Cole (96/2730) reviewed its comparative use with EDXRF and ICP in the determination of Pb in contaminated soils from the same area and concluded that with recent developments in fundamental parameter correction procedures and cooled solid-state detectors portable XRF instrumentation was capable of producing data of good quality. The options for sample pre-treatment appropriate for the analysis of soils at polluted industrial sites were discussed by Christensen (95/3466). Techniques involved varying degrees of sorting grinding and homogenization. In this report a fundamental parameter/backscatter model was used to give quantitative results the backscatter correction offering signifi- cant advantages when analysing loose powders.A Compton scatter normalization stage was also used by Hewitt (96/2581) to correct for matrix discrepancies in the analysis of a variety of solid particulate matrices for As Cu Pb and Zn using a single certified reference material to establish elemental response factors. Elam et al. (96/594) reported on the use of XRF for the in-situ analysis of metals e.g. for the shipboard disposal of waste. The XRF was used as a sensor for a cone penetrometer and the trueness and detection limits of the technique were evaluated. Chromium-contaminated soils near a chrome plating shop were analysed by Puls et al. (96/479). Samples were recovered by a trailer-mounted soil coring unit and field portable XRF results were compared with ICP-AES data from the same samples.Although the correlation between these two data sets was good it was reported that XRF underestimated the total Cr content probably because of 'inappropriate calibration procedures'. Gerlach et al. (96/2773) reported on a case study carried out in 1991 when the US EPA Environmental Monitoring Systems Laboratory in Las Vegas assisted in a remedial investigation/feasibility study at a site in East Fork Popular Creek USA contaminated with mercury after a historic accidental release of material associated with nuclear weapons production. The study reported the development and use of portable XRF as an analytical method for the determination of Hg in stream and floodplain samples the design of an optimum soil sampling strategy the selection and implemention of a method of estimating Hg concentrations using geostatistical methods and the development of a selective extraction procedure to determine the species of Hg in the floodplain soils.In the analysis of geological samples Potts et al. (96/322) undertook a laboratory study of portable XRF in the analysis of seventy international reference materials mainly of silic- ate rock composition and prepared as powder pellets. Instrumentation used 241Am Io9Cd and 55Fe excitation with a mercury(r1) iodide detector and for the most sensitive elements gave detection limits of 6-14 pg g-' (Rb Sr Y Zr Nb) and 21 pg g-' for Ba (K-line) using a count time of 200 s per source. Metals in marine sediments were analysed by Stallard et al.(96/2602) with the instrument used to give near-real-time results on board a small research vessel. Designed for a more exotic location Korotev et al. (96/1182) evaluated the perform- ance of alpha backscatter alpha-proton and X-ray spec- trometry at a hypothetical site chosen to represent the Apollo 17 lunar landing site. They concluded that much of the information about this site (distribution and relative abun- dances of lithologies in the regolith) obtained from returned samples could be obtained from the instrumentation evaluated providing at least one incompatible element was known. Turning now to contamination derived from lead in paint Driscoll et al. (95/C3016) reported that the soil surrounding one 90 year old house in Connecticut reached a level of no less than 10000 mg kg-' at a distance of 1 m from the house owing to weathering of the paint.They described a portable 57C0 excited spectrometer which could be used to assess both the lead content of paint (5-15 s count time) and of soil surrounding the building (60 s count time offering a detection limit of 400pg g-' for Pb). The same laboratory provided information from the portable XRF instrument with a high resolution (cooled) detector designed for Pb in paint and soil (96/314). Epstein et al. (96/C709) developed a slurry-ETAAS method for evaluating hazardous levels of Pb in and around buildings and compared results for Pb on painted surfaces with determinations by portable XRF. This subject was reviewed by Harper et al.(96/1189) who considered both laboratory-based methods (AAS ICP-AES XRF) and field measurements using portable XRF and Pb test kits. A further practical comparison was undertaken of lead paint field screen- ing methods by Hutter and Moshman (95/4054). Three colori- metric and one portable XRF method were evaluated to determine capabilities and characteristics in terms of the appar- ent detection threshold the effect of multiple layers of leaded and non-leaded paint and the influence of colour and surface preparation. Finally field-portable XRF was used to analyse air monitor- ingjlters in a further contribution by Bernick and Campagna (96/1112). Results were reported for detection limits trueness and a comparison with laboratory chemical analyses. 8.ON-LINE XRF On-line contributions are more prominent this year and several contributions described applications in the analysis of cements and ceramics. Yamamoto et al. (96/2583) described an improved sample preparation method for the automatic on-line analysis of ceramic materials by XRF using a glass bead technique. Hasler (96/2722) described a system for the on-line analysis of cement clinker including components for sample preparation (as compressed discs) transport (sample loading manually or by robots) rapid XRF analysis and direct intervention of the production process to correct for production variations. Collins et al. (96/2605) described an automatic quality control system applied to a cement manufacturing plant which uses an EDXRF instrument to function in an integrated manner with a laboratory spectrometer. The EDXRF provided a cost effective solution to the requirement to monitor the manufac- turing process at time intervals shorter than every 3 h and in combination with laboratory XRF analysis resulting in an improvement in quality by a factor of 3.XRF analyses were used by Tschudin (96/1239) to monitor the performance of a new prompt gamma neutron activation facility to control the operation of two blending beds at a cement manufacturing plant. Collatuzo et al. (96/1209) described the use of XRF as an on-line analyser for quality control at a dolomite plant. Metallurgical applications of on-line XRF included that of Creasy (96/598) who took advantage of the characteristic fluorescence X-rays generated when a high intensity electron beam was used to melt metals in a furnace. A specially designed wavelength dispersive spectrometer was used to analyse the composition of the molten metal in situ.Overman (96/2643) reviewed the application of commercial EDXRF instrumen- tation in the surface finishing industry including on-line moni- toring during actual plating or after a product is coated or anodized. Mori (96/2719) claimed a Japanese patent for a method and apparatus for the analysis on-line of multilayer 424R Journal of Analytical Atomic Spectrometry November 1996 Vol. 11plates. The method depended on comparing the X-ray fluores- cence intensities observed at both high and low angles of observation. Sopok (96/2603) evaluated an on-line XRF tech- nique for the analysis of metal finishing solutions such as chromium plating and electroplating solutions.Instruinen- tation from three different manufacturers was compared. but the author concluded that the resultant data did not suggest that this on-line monitoring technique was useful at the time although future developments might change this conclusion. Cocanour et al. (96/487) described a PC-controlled system using a portable EDXRF instrument for controlling the copper concentration in electrolyte cells. Of relevance to the nuclear power industry Connolly and Harvey (96/2721) described an on-line corrosion product moni- tor designed for monitoring nuclear plant feedwater. Corrosion products were collected on membrane filters for analysis by XRF. Day and Vigil (96/382) reviewed on-line EDXRF systems for monitoring actinide contamination waste streams for glove box operations.The aim was to measure actinide and metal impurity concentrations in an anion-exchange effluent in real time with an emphasis on how preconcentration techniques can be used to improve detection limits for on-line EDXRF determination. Instrumentation was modified for operation in a glove box. Other industrial applications were discussed by Hashizume et al. (96/2720) who claimed a patent for an apparatus for the non-destructive on-line XRF analysis of sulfur in rubber. The method was designed to monitor a moving sheet of rubber with a helium path in the analysed section this gas being contained by immersing the appropriate sections of the sheet in a liquid. Fredericks et al.(96/1208) reviewed the determi- nation of S in petroleum products using a commercial instrument. 9. APPLICATIONS 9.1. Sample Preparation Sampling and preparative procedures for XRF analysis have been well established over a number of decades. It is therefore very difficult to be truly innovative in this sphere. The majority of the submissions during this review period are simply re-hashes of existing methods. One Chinese claim however showed exciting new potential. Sun (95/2500) studied the use of a zinc enhancer to reduce detection limits in the analj8sis of trace rare-earth metals. By using 50 pg of ZnO as the enhancer and Eu as a representative rare-earth analyte the detection limit was lowered from 0.05 pg g-' to 0.0056pg g-'. Unfortunately since very little experimental detail was avail- able to the reviewers the validity and importance of this claim is difficult to evaluate.Platinum crucibles were the subject of a patent claim by Matsushita (96/1125). A crucible of particular use in the analysis of iron ores slags and fluxes consisting of a flat bottom walls and horizontal flanges was designed so that the upper part of the wall (not in contact with the molten glass) comprised Pt-5% Au or Pt-5% Au-10% Rh and the lower part comprised Pt-0.16% oxide (possibly PtO,)-5% Au. Further patent applications were from Iwata and Maruyama (96/522) who claimed an efficient and high precision method for the preparation of glass beads from the more difficult type of samples such as those containing reduced metal or sdfides.The method consisted of filling a Pt or Pt alloy vessel with sample and flux pre-melting pulverizing the cooled glass re-filling the vessel and re-melting. Sad0 (96/446) claimed a method based on mixing sample powder with an organic solidifying agent and an inorganic matrix modifier fo Ilowed by heating and formation of a slurry casting the slurry and cooling. The summary of all these claims is rather vague and may well lose something in the translation from Japanese so it is difficult to assess the degree of innovation. More clear cut was the patent application for a new medium for XRF pressed disc analysis by Wachsmann and Hirsch (96/2767). Binders composed of poly(vinylpyrro1idone) containing 10-80% of microcrystalline cellulose were proposed. Whether they will have any advantages over conventional binders only time will tell.A similar application for the use of a solidification agent in the analysis of lubrication oil and grease was put forward by Inoe (96/2640). An unusual approach to specimen preparation for the XRF analysis ofsolutions was taken by Eksperiandove and colleagues at the Institute of Single Crystals Kharkov Ukraine (96/2765). Dry gelatine (10%) was added to the analysis solution and the mixture homogenized and cooled for 20min to produce a compact resilient mass which could easily be shaped. As with the fused bead technique surface texture was determined by the surface on which the specimen was formed (highly polished by choice). Cob0 et al. (96/2653) developed a re-melting technique for the analysis of ferromolybdenum and ferroniobium.These two materials pose difficulties in the application of XRF techniques they are not very suitable for direct instrumental analysis and it is difficult to obtain accurate calibration samples in a suitable form. The re-melting technique was reported to change the physical form of the ferroalloy into one appropriate for XRF measurement and enabled the addition of pure iron which avoided problems of sample fracture during cooling chilling or polishing. Calibration samples were prepared either from a commercial ferroalloy diluted with variable amounts of iron or from pure Mo and Nb with iron additions. Test samples were prepared by re-melting the ferroalloy diluted with iron in the proportions 15 g of FeMo + 25 g of Fe for ferromolyb- denum and 12 g of FeNb+28 g of Fe for the ferroniobium.Precisions better than 0.6% were achieved for both ferroalloys using either WDXRF or EDXRF. Tungsten carbide (WC) has been the dominant form of sample comminution for a considerable time so the report by Hergt and Sims (96/449) on the contamination eflectsfrom WC crushing offers nothing new to the regular user but gives guidance to potential newcomers to the world of simple crushing. The crux of their findings was that WC should not be used as a grinding medium when low levels of W Co Ta Pb and Nb are required. A method for improved precision of quantitative XRF analysis using glass beads was reported by Yamamoto et al. (96/626). The authors observed that the X-ray optical characteristics of equipment affected precision measurements.For focused (curved) crystal spectrometers the precision was reported to depend on the deviation of the actual size and position of the crystals from those of theoretical designs and was therefore affected by crystal selection for a given element Furthermore a waviness of the surface of glass beads was also reported to change the mean height of the analysed surface so affecting the flux of X-rays incident on the analysing crystal and increasing the dispersion of the X-ray intensities. It was claimed that by mechanically flattening the glass bead surface the level of waviness could be regulated at under 30 pm and the relative standard deviation for the measurement of Pb L#l in ten glass beads of the same sample could be improved by a factor of almost ten.During an assessment on the accuracy of the XRF analysis of oxides silicates and carbonates using synthetic fused bead calibration standards Giles et al. (96/988) found that for iron there was a consistent bias when values for 43 reference materials were compared with certified values. After the elimin- ation of the more likely sources of error (e.g. human weighing errors) the stoichiometry of the pure iron(Ir1) oxide used as the calibration source was questioned. Supplier specification claimed 70-70.1% m/m as Fe (compare 69.945% m/m Journal of Analytical Atomic Spectrometry November 1996 Vol. 11 425Rtheoretical) whereas actual determination carried out by the authors gave values of 70.97% m/m and 69.98% m/m on two different batches.To avoid problems caused by non-stoichio- metry of the oxide calibration was then carried out using 99.999% purity iron metal with a marked improvement in the calibration slope (1.001 compared to 1.015). This report is a timely reminder to all spectroscopists that for all pure oxides used as calibration standards the metal content is as equally important as the level of trace impurities (particularly when the metal forms stable oxides of different valency states). Yamamoto (96/1123) developed an on-line system for the preparation and validation of standard beads in XRF analysis. The automated system included a proper choice of reagents assignment of bead composition and validation of the prepared beads and featured a fundamental parameter method for the validation an original database of high purity reagents and automatic calculation of suitable composition for each stan- dard by giving a range for each element and the number of standards required.The deterioration in pressed pellet samples over a period of time was investigated by Novosel-Radovic and Maljkovic (95/C4202). Observations that briquetted standards with both inorganic and organic binders diminished their resistance to cracking and specimen damage after prolonged time of use resulted in an investigation into the influence of irradiation time on the usability of briquettes. Standards were prepared from Li2C03 KC1 Li2B407 and Na2B,07 after grinding for 30 min in a WC mill followed by irradiation by primary X-ray beam (25 pm/45 kV) for 1 to 5 h. Diffraction patterns from a Philips diffractometer system using Co Ka radiation indicated changes of line profile and preferred orientation with radiation time.Electron micrographs also showed changes in surface structure. Thin film specimen preparation with special emphasis on choice of Jilter paper was studied by Yu (96/2562). Although this technique is very simple the inhomegeneity of the sub- strate-filter paper and the chromatographic effect for diffusion of ions into the paper influence the measurement of X-ray fluorescence intensity. During the study factors such as the homogeneity linear thickness mass thickness and diffusion behaviour for twelve commonly used filter papers were com- pared and finally an optimized filter paper specimen prep- aration method was recommended.The use of solvent impregnated filter papers was investigated by Chen and Xiong (95/3396). Fast filter paper soaked in a solution containing 2-ethylhexyl hydrogen 2-ethylphosphonate-4-benzoyl-3- methyl-1-phenylpyrazol-5-one (2 1) in benzene (40 ml) was used to filter samples (ten times followed by washing to neutrality and drying). XRF analysis was performed giving detection limits for elements determined of 0.359 pg (Ce) 1.08 pg (Hf) 0.315 pg (La) 0.622 pg (Th) 0.709 pg (Yb) and 0.666 pg (Zr) (RSD 3 5 6 % ) . The papers were found to be stable for 4 months. A review was presented by Revenko (95/3397) on state-of- the-art procedures for the preparation of ore rock soil and plant thin-film or pellet samples prior to EDXRF analysis. Effects of dilution with binding additives and fluxes on the analytical line intensity were considered and also with refer- ence to the plant material sample preparation techniques of grinding pressing and ashing and the use of fine emitters were discussed. 9.2.Preconcentration Techniques The significant contribution from Chinese laboratories last year has not been repeated so there has been a bit of a lull in this area of activity during the current period. A few preconcen- tration methods for the trace anaZysis of waters and aqueous solutions by XRF were reported. Ducos-Fonfrede et al. (96/1131) measured U traces in water after the liquid-solid extraction of MnO resin. The preconcentration stage occurred on a medium prepared by reaction of aqueous KMnO solu- tions on an anion exchanger (Dowexl X8 resin).Amorphous Mn oxides were generated in the reticulated structure of the resin. This medium is apparently able to adsorb many inorganic micropollutants present in water without trapping macro components. Using the method for natural waters containing traces of uranium gave a recovery coefficient of 85%. Isami et al. (96/1197) determined hazardous trace elements in water (As Cd Cr6+ Hg Pb Se) by XRF after precipitation with NaDDC. 1-( 2-Pyridylazo)-2-naphthol immobilized on silica was used by Ponce et al. (96/2762) to preconcentrate lead@) in aqueous solution prior to determination by EDXRF. Preconcentration techniques relating to nuclear fuel were reported by Hanif et al. (96/1008) who studied U-Ce admix- tures in nitric acid solution.Specimens were prepared by wetting filter papers fixed on Scotch tape with microdroplets of the solution fixing on polyethylene cups and drying under an infrared lamp. Ce La and U La lines were chosen and a better than 2% accuracy claimed. A similar approach was adopted by Mudher et al. (96/2768) to determine uranium in liquid samples by absorbing drops of solution onto cellulose discs. Sr Th or Y were used as internal standards to follow the non-uniform absorption of the liquid on the disc. A precision better than &0.5% was obtained for U with all three internal standards. The method also showed no interference effects from Am and Pu so could be used to determine U in their presence. Other preconcentration procedures were described by Bao (96/365) who presented the use of polyurethane foam as an adsorbent of trace gold.Determination of gold was also the interest of Logunova et al. (96/2665) who developed systems based on low-melting organic acids in particular on aliphatic monocarboxylic acids (C,7-C,0) for its extraction and precon- centration. Ilic et al. (96/1931) used the precipitation of acti- vated carbon cloth with metal-organic compounds to characterize the cloth by studying each activation component. AAS and EDXRF were compared both proving useful in the characterization of non-pregnated and impregnated carbon cloth. Pascual and Cortazar (96/2574) applied preconcen- tration to the determination of AS"' AsV and total arsenic in plant material (peach tree). Following acid digestion the arsenic was separated from solution by preconcentration with sodium dibenzyldithiocarbamate (DBDTC) and co- precipitation with iron(Ir1) hydroxide.The precipitate was collected by filtration and examined by WDXRF. A detection limit of 0.1 pg g-' was reported with an accuracy and precision of greater than 5%. 9.3. Geological The number of reviews received in this area once again shows the significant use of XRF as an analytical tool. Several papers were published in the field of soil and sediment analysis. Some such as those by Villagran et al. (96/1345) Cevik et al. (96/2594) and Akyuez et al. (96/538) used established methods of analysis. The first used XRF with a Zr secondary target to measure the Hg content of dried and homogenized sediment following Mossbauer spectral analysis.The second using EDXRF with an annular ',lArn source for excitation and Ge(Li) detector measured the Ba Fe and Sr content of eastern Black Sea sea-bed sediments and the last used EDXRF to study the distribution of Ba Cd Ce I La Mo Rb Sb Sr and Zr also in samples of Black Sea sediment. One application of more interest was that by Sat0 et al. (95/3465) who described a low dilution fusion technique for the analysis of submarine sediments. A fusion mixture of 1.644 g of Li2B407 0.3 g of Li2C03 0.04 g of NaNO and 0.016 g of NaI was mixed with 426 R Journal of Analytical Atomic Spectrometry November 1996 Vol. 112 g of sample heated at 600 "C for 5 min to oxidize organic matter and finally fused at 1050-1 100 "C for 7 min. Theoretical alpha coefficients were used to give improved results over uncorrected ones and detection limits for Cr Cu Mn Ni Pb Sr and Zn were reported as 2.1 2.4 1.5 1.2 1.9 1.5 and 1.6 pg g-' respectively.A pressed disc method using boric acid backing was used by Gunicheva et al. (96/408) to analyse soils and friable marine sediments. The minimum amount of sample required to give an 'infinitely thick' emitting line for Rh Ka for each sample type was calculated and analysis was performed using WDXRF at 40kV with a Rh target tube. The Rh Ka line was used as an internal standard for some elements. When compared with standard reference materials results were good (with the exception of Si). The biological complexity of the materials prohibited the use of a fusion technique for major element determinations.Calibration methods using reference materials for the analysis of sedimentary deposits were described in two papers by Obol'yaninova et al. (96/634 and 96/415). Janik et al. (96/1183) used analytical data obtained by XRF on 100 soils selected from a set of 298 samples taken throughout eastern and southern Australia to correlate infrared data using partial least squares analysis (PLS). The results were used in a geochemical mapping exercise. In a similar exercise Hiraoka (96/450) analysed soils from 110 sites in the Kyoto area of Japan in order to predict the origin of soils for forensic applications. A '71 YO probability of correct identifi- cation was claimed. Various applications relating to the analysis of rocks were described. Ossaka et al. (95/3407) used XRF for the major element analysis of rock and volcanic ash samples in the Unzen area of Japan.A flux to sample ratio of 10 1 was used the fusion process being carried out in a platinum mould in a borax bead machine. A method for the determination of extremely low (sub 0.5 ppm) levels of rare earth elements in rocks was described by Gong et al. (96/372). Sample prep- aration was carried out by treating with 3 ml of 1% ascorbic acid and 10ml of a mixed masking agent containing 2% EDTA 0.5% CDTA and 2% EGTA followed by adjustment of pH to < 1.5 with aqueous ammonia and hydrochloric acid. Portions were passed through an m-acetylchlorophosphunazo impregnated fibre ion-exchange column where a chelate- forming fibre was collected and dissolved in HN03 and HC104. Using MgC12 as a carrier aqueous ammonia was used $is the precipitant.The precipitate was analysed by XRF using the standard additions method correcting for backgrounds and spectral interferences. Recoveries of rare earths be tween 84-107.5% were reported together with detection limits between 0.052 and 0.21 Fg g-'. Very low traces of V anid Ni were determined in rock extracts by Yu (95/3866). Samples were prepared by dissolution (five to ten-fold) in IBMK and then transference in three 50 pl portions onto a formed filter paper on a support by the dripping method and dried XRF analysis was carried out with V Ka and Ni Ka lines using V and Ni organometallic standards. By utilizing a standard additions method recoveries of 98-105% and 97-106% were obtained for V and Ni respectively with detection limits of 0.32 and 0.35 pg.The transmission method was used to reduce background scattering. An XRF fusion method for the accurate determination of reduced sulfur in rocks was described by Awwiller (96/476). The author claimed improved couni rates for light elements relative to those from a heavy absorber lanthanum oxide-based flux. Using an automatic high fre- quency furnace bead-sampler Oishi et al. (96/2772) prepared samples of rock for XRF analysis (Cr-tube) from 0.8 g of rock powder + 4 g of Li2B407. Ten major components were ana- lysed using calibrations based on reference rock samples primarily from US and Japanese Geological Surveys. A method combining ion exchange and XRF for Y and lanthanides in rocks and minerals was described by Gasquez et al.(96/2579). Following sample dissolution with HF-HClO (or alkaline minifusion with NaOH for refractory minerals) a dry cation exchange resin (in acid medium) conditioned on a special cellulose support was used to separate the elements Ce Er Gd La Nd Pr Sm and Y. The method was applied to a geochemical study of the northern part of a batholith in San Luis Provence Argentina. Routine uses of XRF and AAS for the analysis of silicate rock were described by Ikram et al. (96/385). Other geological applications included the determination of Th as the main source of high environmental radiation by Pate1 and Mangala (96/423) in a study of 30 radioactive carbonatite samples from four zones of the Mrima Hill Kenya. The elements Ba Ce Fe and Nb were also found worthy of economic exploitation.Hua and Yap (96/475) presented an accurate method for the determination of major and minor elements in iron-rich and other geological samples using XRF. A fusion sample preparation method was used and theoretical alpha coefficients were calculated for matrix corrections. The use of pressed pellet sample preparation was reported by Longerich (96/403) in the determination of 30 elements for a number of silicate geological reference materials. The sample was mixed with a bakelite phenolic resin and heated to 200 "C prior to pelletizing. Interferences were established by the similar preparation of single element pellets. Several matrix correction models were employed dependent on the element analysed. Simabuco and Filho (96/638) made reference to the use of the transmission method applied to geological samples in the analysis of three certified samples of different matrixes by EDXRF with radioisotope excitation.Instrumentation com- prised annular radioactive excitation sources ("Fe and lo9Cd) and a Si( Li) semiconductor detector coupled to a multichannel emulation card in a microcomputer. The fundamental param- eters method was used to determine elemental sensitivities and the transmission (or irradiator) method applied for the correc- tion of the absorption effect of X-rays of elements of atomic number 22-42 (Ti-Mo) which were excited with lo9Cd. Element lines in the atomic number range 13-23 (Al-V) which were excited with 5sFe were not transparent to incident and emergent X-rays and a method for absorption correction based on the experimental value of the absorption coefficients associ- ated with absorption edges of the elements was developed.High productivity geochemical analysis was the subject of papers by Ingham and Vrebos (96/637) and Elsenbroek (96,4108). Both detailed aspects of instrumentation sample preparation and calibration required for a high sample throughput. Analytical assessments relating to geochemical samples were reported in several publications. Ramsey et al. (95/4275) in what appears to be an extensive study carried out a precision evaluation of ICP-AES and XRF by applying the method of Thompson and Howarth (1976) to the duplicate analysis of 55 igneous rocks. Determinations were made using four evalu- ations based on the two analytical techniques as operated under routine working conditions in two participating labora- tories. The two XRF evaluations were of major elements on fused glass beads and trace elements on powder pellets while the two ICP-AES evaluations were of major elements after a fusion decomposition technique and trace elements together with selected majors after an acid attack.Median high-level precisions of the techniques used for major elements were reported as 0.23 YO relative (XRF-glass bead) 0.43 YO relative (ICP-AES-fusion decomposition) and 0.70% relative (ICP- AES-acid at tack). Providing elemental concentrations extended over a significant range typical precision values in the trace determinations by both techniques were 1.5%. Nekab et al. (95/2874) compared PIXE XRF and NAA for the determination of rare earths in geological and mineral samples.They concluded that PIXE was not suitable for rare earth Journal of Analytical Atomic Spectrometry November 1996 Vol. 1 1 427 Relements at low concentration XRF was more sensitive but not applicable to pg g-' levels and NAA could be used at pg g-' levels but required more complex sample preparation and a longer analysis time. A statistical study of data obtained by repeated XRF analysis of many major and 13 trace compo- nents in 20 reference materials was carried out by Bostroem and Bach (96/1203) aboard the ship Joides Resolution. Their results showed that as well as being an excellent tool for the determination of most main elements in many rocks it was also very suitable for some trace elements (e.g. Nb Rb Sr and Y at 4-10 pg g-I).It was also possible to obtain XRF data on board ship of comparable quality to that from land-based laboratories. Trace elements difficult to determine by XRF included Ba (<20 pg g-I) Ce V and Zr. 9.4. Environmental Of major concern in the environmental field is the issue of contaminated land. Some studies are reported in the portable XRF section of this review (Section 7). However a significant input into this area has been observed during this review period. A study of the contamination of the surface layers of soil by heavy metals (particularly As Pb and Zn) in an area around a steelworks located in an industrial sector of Krakow Poland was reported by Ostachowicz et al. (96/597).EDXRF with radioisotope excitation was used together with the trans- mission method for matrix correction. Comparison was made with areas in the city centre. Analyses of more than 140 samples of soil were carried out and concentrations of 0-30 pg g-' for As 15-200 pg g-' for Pb and 40-650 pg g-' for Zn were reported. The distributions of Pb content in the two regions of Krakow were similar whereas that for Zn was different being higher in the industrial area. The authors concluded that there were different sources of contamination in the soil Pb originating from automobile transportation whilst Zn was predominantly from industry. Janczyszyn and colleagues (including the previous author) (96/1161) continued the exercise by analysing soils from the same area as well as from more distant sites using INAA as well as EDXRF to determine the elements As Cd (by AAS) Co Cr Mn Ni Pb Sb Th U and Zn.The concentrations of biologically important metals were not drastically higher than typical or tolerable values for soils with the exception of Pb and Zn whose concentrations were often higher. Again Pb contamination was attributed to petrol engined vehicles. Se and Hg were also studied but no values exceeding the lower detection limits for INAA were found. Oluwole et al. (96/468) used EDXRF together with HPGe-based passive gamma spectroscopy to measure toxic heavy metals and radionuclide concentrations in soils around a lead-tin smelter air particulates and mining wastes collected from some tin mines and a tin mill. The elements As Bi Ni Pb Sn and Zn were highly enriched in soils air particulates and mine wastes.Th and U concentrations were measured at 0.01-2.94% m/m and 0.002-0.11% m/m respectively in tailings and 2.25-9.09% m/m and 0.25-0.56% m/m respectively in monazites. Implications for radiological waste management were discussed. Soil pollution by As from tannery waste was studied by Sadler et al. (96/478). In many years of operation arsenic compounds including sodium arsen- ite had been used as pesticides at the tannery and As had found its way into the soil as liquid waste disposed of by burial or spray irrigation. Although concentrations recorded by XRF were comparable to those in soils polluted by agricul- tural use of the pesticide or by mining activity pollution from this source extended to a considerable depth through the soil profile.Evidence of arsenic movement through the soil was provided by soil water analysis using hydride generation and confirmed by batch leaching of soil samples with distilled water. Knipping (95/3876) reported the use of sequential WDXRF and XRD for the analysis of soil and waste samples. For XRF samples (0.6 g) were fused with 3.6 g of Li2B,07 to produce glass beads or if they were metal sulfides or contained As or Cd pressed into tablets ( 5 g of sample to 1 g of binder). An iterative procedure was used for matrix and overlapping line corrections and 70 elements were measured in 20 min with detection limits ranging from 0.5% m/m for F to 1 pg g-' for Br. Determinations of Cu Ni and Zn in contaminated land were particularly important because of their phytotoxicity.Wilson et al. (96/601) compared the determination of these elements by XRF and ICP-AES. The XRF results were either comparable with or slightly higher than ICP results but when related to the threshold values for contamination each set of results led to the same conclusion with respect to the categoriz- ation of the contaminated site. It was thus demonstrated that either method could be used to screen soil for phytotoxic metals. XRF was one of 18 different techniques used in the certification of environmental soil standard reference materials by Li (95/4041). It was also used to evaluate the stability of the samples over a 1 year period. A comparative study of the use of AAS ICP-AES potentiometric stripping analysis (PSA) and XRF for the determination of Cd and Pb from a polluted hazardous waste site was presented by Pyle and colleagues (96/2582).The authors showed that in general the four techniques gave comparable results with PSA and AAS having the best agreement. XRF results were lower than or equal to those by ICP-AES and AAS and lower than PSA. Urban soil and dust was the topic of a paper by Vincent and Boyer (96/1193) who examined the use of XRF AAS and ICP to measure Pb in samples for an Urban Soil Lead Abatement Project (USLAP). Results from multi-sample XRF Pb determi- nation in soils and dusts were examined to establish accuracy and precision baselines for the use of XRF to analyse real- world samples using a prescribed protocol. The importance of good sample preparation was stressed.The same authors together with Elias (96/1187) as part of the same project described a double-blind audit system as a quality control measure. Dust related methods also included Williams et al. (96/1192) who developed protocols for preparing method evaluation mate- rials from real-world lead-containing paints and dusts. Materials were evaluated in a round-robin exercise using five combinations of preparation and quantification techniques including XRF. Data presented included homogeneity evaluation of the sample as well as repeatability and reproducibility of the methods used. The characterization of lead-rich post-abatement dust samples collected with a HEPA vacuum filter was described in two different contributions by Mamone et al.(96/1196 and 96/1127) who used EDXRF to determine Pb on three size fractions of resuspended dust collected on Teflon filters. Automated SEM was used to determine the size morphology and chemistry of individual particles from 0.2 to >250 pm. Not surprisingly minerals associated with construction materials paint fillers and soil were the dominant species in all size fractions. The Pb-rich particles found in all sizes were grouped into three categories Pb-only (including PbO and PbCO,) mixed Pb-minerals and automotive Pb. Isolated PbO and PbCO particles derived from paint pigments were the dominant forms of Pb-bearing particles in the < 15 pm size fraction. Domestic pollution was covered in a number of papers the most prominent being the subject of lead in household dust.Renault and McKee (96/323) developed what appears to be a simple rapid method using only ~ 1 0 m g of sample dust which was applied to an acrylic transfer tape. Data were collected for the Pb LP line using a WDXRF spectrometer at 60kV 45mA. Two background lines were used and the Pb calculated with reference to a single calibration sample. Good comparison with flame AAS was obtained. Bero et al. (96/1167) expanded a 1992 study of the feasibility of XRF to analyse 428R Journal of Analytical Atomic Spectrometry November 1996 Vol. 11lead and soil loadings on carpeted surfaces and developed calibrations for three different carpet types based on Ph LB Fe Ka and Ba Ka peaks and background areas. Carpet type was shown to affect the calibration.Detection limits of m70 mg mP2 for lead and 5 g m-2 for soil were obtained. In a study by Li (96/433) lead was one of twenty elements determined by XRF on sixty PMlO aerosol samples simul- taneously collected in the indoor and outdoor air of fifteen homes in the Taipei urban area; 10% of indoor and 20% of outdoor samples were reported to exceed the USEPA 24 h standard for PMlO level (150 pg m-3). Concentrations of Al Ca C1 Fe K S and Si were dominant both indoors and outdoors all having arithmetic mean levels higher than 1 pg m-3. The median values of indoor/outdoor ratios were smaller than 1 in m8O% of the samples and > 1 in the rest. The elements Br Mn Cu Pb S and Zn showed the highest correlation coefficients between the two types with Al Ca Fe K Mn Si and Ti being well correlated.High enrichment factors (both indoors and outdoors) were observed for Br C1 Pb S and Zn and attributed to sea salt industrial operations and automobiles. The analysis of mineral substances in drinking water was described by Warner et al. (96/1135) Ca C1- K Mg Na and S042- being measured simultaneously with a sequential X-ray spectrometer. Samples were dried onto a polypropylene foil adding GELERITE (a polysaccharide) to reduce the hydro- phobic effect of the foil. This method had several advantages over AAS and ion chromatography (IC) for the simultaneous determination of anions and cations (1) no acid or other aggressive chemicals were needed ( 2) large calibration ranges eliminated tedious dilutions and (3) the process was faster and more reliable since matrix effects could be applied. Detection limits of 0.12 1 0.32 1.78 1.34 and 1.08 mg 1-1 were obtained for Ca K C1- S042- Mg and Na respectively.Other water applications included those by Vleugels and Van Grieken (96/1168) who studied the effects of air pollution on stone deterioration by the analysis of the run-off water from limestone exposure racks and by Peraniemi and AhlgrCn (96/2024) who developed a procedure for the separation and independent determination of microgram quantities of CrV' and Cr"' in aqueous solutions. CrV' was adsorbed onfo zir- conium loaded activated charcoal and Cr"' was collected by Fe(OH) precipitation followed by binding the precipitate to activated charcoal. The levels of chromium were measured by EDXRF the detection limits being better than 0.05 mg I-' for both species. The procedure was tested with groundwater and a waste water pollution control check standard WP-15 spiked with CrV' together with several samples taken from the plat- ing industry.Iwatsuki and colleagues at Yamanashi University Japan (96/2769) developed an XRF method using a coprecipitation preconcentration stage for the simple determination OF both acid-soluble and insoluble trace metals (particularly C'u Fe Mn Ni and Zn) in sea salt. The sample was dissolved in HN03 solution and the residue filtered onto a membranr filter. After adjustment of the pH to 7-8 the filtrate was boiled followed by addition of A1 carrier 8-hydroxyquinoline and thionalide solutions. The solution was re-adjusted to pH 9 and kept at 80-85 "C for 1 h whereupon the precipitate was jiltered onto another membrane filter.X-ray fluorescence intensities from the two filters were measured and the concentrations of the elements determined simultaneously. Detection limits of 0.01 pg g-' for Mn and Cu 0.04 pg 8-l for Ni and Zn and 0.05 pg 8-l for Fe were reported. Aquatic sediment was the theme of two papers. In the first Baudo et al. (96/2778) as a contribution to the verification of the reliability of P determinations described results obtained from the analysis of sediments from an Italian lake by a variety of techniques (one of which was XRF). Accuracy precision and compatibility of the techniques were discussed. The second by Komy (96/2774) concerned the analysis of major and trace elements in sediment samples taken from twelve locations along the River Nile. Elemental analysis by EDXRF was carried out on bulk sediments and also on separated clay-silt size fractions.Results showed that the metal distribution along the Nile was more dependent on pollution input than on chemical weathering and an almost linear increase of the trace metal content was observed from south to north. No significant difference in samples from the west or east banks was noted but bulk samples collected from the High Dam exhibited much lower content in Ca Fe and K. Most transition element contents were close to detection limits. Two papers were received on the subject of incinerator ash. Haschke et al. (96/570) tested EDXRF for rapid elemental determination in various areas of refuse incinerator plants input and operational material flue gas treatment and residues.Improvements to the limits of the method were made by excitation with polarized radiation. Comparisons with other methods were discussed and an indication given that the method could be successfully applied both for rapid input control and for operational tasks. Short and long term hazards from municipal solid waste incinerator (MSWI) ash were assessed by Buchholz and Landsberger (96/1195) through the elemental analysis of forty to fifty elements in the ash and leachates from several leaching procedures. XRF and NAA were used for the ash and NAA and ICP for the leachates. Ag Ba Be Cr Cu Mo Pb Sr and Zn were identified as being the greatest hazard posed by MSWI ash monofills with As Cd Cu Hg Pb S and Zn as potential long-term hazards.The pH of the leachate was shown to be the single greatest factor governing the concentration of metals in solution being more important than the actual concentration of the metal in the ash. Results were applied to the assessment of the suitability of the Toxicity Characteristic Leaching Procedure (TCLP) in measuring the leaching potential of an MSWI ash monofill. Finally since no environmental review could be complete without some reference to air pollution this subject was the theme of several papers. Baryshev et al. (95/4570) sampled atmospheric aerosols and aqueous suspensions on mylar filters having a regular rectangular array of 0.4 pm diameter holes spaced 1 pm apart. These filters have no dispersion of pore sizes caused by superimposition or merging of holes.The material collected was analysed by 23 keV synchotron XRF for Ca to Mo (Ka lines) and Pb (La) with a 5 min counting time. Comparisons were tabulated for the regular filter and a nuclepore filter most notable disagreements being reported as Cu (0.1 pg cm-2 on regular versus 0.63 on nuclepore) Fe (14.6 versus 8.9) and Mn (1.22 versus 4.8). Electron micrographs of the aerosol and suspension loaded regular filters were also presented. A validation study for the determination of Hg in power plant flue gas was reported by Cooper et al. (96/1225). The method combined activated carbon impregnated filter sampling with XRF analysis. Air pollution monitoring was the interest of several groups. Smodis et al.(96/2659) reported on the methodology and analytical development (NAA and XRF) for a series of projects in Slovenia concerni'ng toxic elements heavy metals and radio- nuclides in the atmosphere. Similarly according to Diaz et al. (96/2641) XRF was used to study the elemental composition (mainly sulfur and heavy metals) in the lower atmosphere of San Lorenzo Paraguay. Concentrations of As Br Ca Cr Cu Fe K Mn Ni Pb Rb Sr Ti and Zn were reported and compared with two rural locations. A survey of the Jamaican environment was the subject of a report by Lalor et al. (96/2645). The survey began in 1991 to determine typical and acceptable background levels and to pinpoint polluted areas for further study and to date 23 sites have been sampled and over 400 samples have been analysed by NAA and XRF.Journal of Analytical Atomic Spectrometry November 1996 Vol. 11 429RPla et al. (96/2650) reported that XRF and NAA would be developed as methods in proposed pollution studies in Buenos Aires. The analysis of aerosol particulate samples collected on filter substrates is still an area of growing concern in large scale monitoring campaigns. In this context Haupt et al. (96/1004) presented results for an intercomparison of two different techniques to produce standard filter materials for the EDXRF analysis of aerosol filter samples. In one multi-element stan- dard solutions were dropped onto Munktell quartz-fibre filters and air dried whilst the other utilized an aerosol generator to deposit on the filter surface. Extensive calibration procedures were carried out with both types of standards and the data applied to the analysis of urban aerosol filter samples.Results indicated that the aerosol technique provided good accuracy (even for light elements) but the dropping technique was not suitable for fibre filters both in terms of the calibration of light elements and achieved accuracy. The authors concluded that the aerosol technique should be used generally for the preparation of standard filters the method providing small particles and homogeneous coatings of multi-element stan- dards. Rausch et al. (96/2658) investigated (by INNA XRF and GC-MS ) several toxic heavy metals and volatile organic compounds (VOC) in various types of Hungarian fly-ash fine particles taken from within a power station.The samples were taken from the boiler zone (BO) the electrostatic dust filter chamber (FI) and the flue-gas at the top of the stack (ST). Enrichment rates of the toxic metals both in FI and ST particulate fractions related to the BO concentrations were calculated to enable the temperature dependence on the adsorption of the toxic components to be studied. From the VOC measurements 3 1 organic species were identified. Since Hungarian brown coals are high in U and Th content the specific radioactivities of the daughter isotopes of both the 292Th and 238U decay series were also measured and discussed. Two papers were concerned with the analysis of airborne particulate matter in Santiago Chile. One by Tor0 and Cortes (96/2567) described their sampling procedures chemical deter- mination and daily behaviour. The particulate matter was collected onto polycarbonate membranes (one of fine and one of coarse pore) using PMlO samplers and analysed using NAA PIXE XRF IC voltammetry and isotope dilution.In the other Poblete et al. (96/2561) reported a procedure for the non-destructive analysis of Fe Pb and Zn using XRF and compared results with those from other techniques. Homogeneity of Fe in the samples was also studied. Nejedly et al. (96/2760) reported on a three month monitoring project carried out at a rural site in South West Ontario. Samples of fine and coarse air particulates were collected using five different sampler types in parallel and analysed by PIXE Proton Elastic Scattering Analysis (PESA) EDXRF and IC.The evolution of XRF as a normalized procedure for the chemical analysis of lead in atmospheric particles was thor- oughly described in an article by Quisefit (96/2655). Impurities in materials used as air filters was studied by Lartigue et al. (96/2654) using lo9Cd EDXRF. Glass fibre filter was not surprisingly reported to have the highest levels of Ca Ba Fe Pb Rb Sr and Zn whilst Teflon had the lowest impurity level. Reviews of these and other relevant applications are available in the ASU update of environmental analysis (96/1444). A more specialized review was provided by Jambers and col- leagues (95/3 1 12) on recent advances in the analysis of individ- ual environmental particles. A review of analytical techniques (including XRF) ideally suited to routine air monitoring pro- grammes particularly in urban environments was prepared by Landsberger and Biegalski (96/2642).9.5. Archaeological and Forensic XRF was among the techniques used for .the analysis of glass of archaeological interest in two papers. Frosch and Ruthenberg (95/4038) described the analysis of a glass originating from about AD 1700 cut in Thuringia (Germany). The sample was a K,O-CaO glass with an unusually high As203 content ( N 8%). Koelling and Kunze (95/4039) reported on the analysis of two ancient glass beads found during excavations close to Lake Assad in Syria in 1991 originating from between A number of references were made to the non-destructive analysis of gold and silver objects and coins. Stern (96/1164) reported on the analysis of Celtic gold coins with gold contents from above 95% to below 20%.The use of the low energy Ag L-line and also its high energy K-line to give different penetrat- ing power was used to investigate the technology of surface treatment i.e. plating and depletion gilding. Araujo et al. (95/2493) compared EDXRF and PIXE in the analysis of ancient gold coins containing 35-99% of Au for the elements Ag Au and Cu. They concluded that for coins containing >96% Au there was no significant difference but for lower Au contents the results for Au by PIXE were higher by up to 15% (attributed to surface enrichment in Au and lower penetra- bility of protons than of X-rays). Waldhauser (96/1162) used XRF for the analysis of gold artifacts dating from the 8th to the 1st Century BC found at about 150 sites in present-day Bohemia.Chen et al. (95/3504) determined gold silver and platinum in gold and silver ornaments using XRF in combi- nation with a transmission irradiation-mathematical correc- tion-specific gravity test. The effects of sample size form and surface roughness on results were discussed. Other archeological applications included Chen et al. (96/1998) who used XRF to measure rare-earth elements in ancient pottery of the neolithic age in the Su Wan area along the Yangtze river. They reported that the distribution of the rare-earth elements varied with the sites where the pottery was unearthed and therefore their analyses may help explore the ancient pottery production sites and the route of cultural exchange. Vazquez and Escola (96/384) used WDXRF to determine the concentration of five trace elements (Mn Rb Sr Ti and Zr) and one major (Fe) in groups of obsidian samples from Argentina.The method was used to establish the source of a number of prehistoric obsidian artifacts. Frana et al. (95/C3760) used XRF to determine Ag As Fe Ni Pb Sb Sn and Zn in archaeological bronzes from Bohemia to classify them chronologically. In another bronze application Brewer (96/2657) used XRF and AAS for surface examination analyses of the metal in a study of the technology of Renaissance bronzes. EDXRF and WDXRF were used by Mitsuji (96/2578) to analyse Ca K Rb and Sr to classify Sueki (Japanese ancient ceramics) kilns throughout Japan. The mural ‘America Tropical’ by David Alfaro Siqueiros was studied by Pique et al. (96/2646) both in respect of the artist’s innovative technique (fresco on cement) and to the mural’s deterioration.XRF together with polarized light microscopy was used to examine the pigments in the paint in an attempt to source the original materials. FTIR organic elemental analysis and GC were used to identify the binder as cellulose nitrate and the deterioration of the mural was discussed in the light of the experimental data accumulated. In the forensic field Rapp and Townsend (96/1110) used XRF for the non-destructive analysis of ammunition in particu- lar of lead shotgun pellets. They showed how useful the technique can be in assigning the identity of an ammunition source. An energy dispersive system was used to correlate the antimony content of shotgun pellets with standard alloys.Suzuki et a!. (96/1235) described a simple rapid technique for the analysis of vehicle headlight glasses to use the analytical data for forensic comparison. The glasses were treated with alcohol and the suspension filtered uniformly onto a filter paper and fixed on the paper with an aqueous collodion solution. The filter paper was then subjected to conventional 2000- 1500 BC. 430 R Journal of Analytical Atomic Spectrometry November 1996 Vol. 11XRF analysis for the elements Al As Ba C1 Fe K Na Si Sr and Zr. The elements As Fe K Na and Zr showed character- istic differences in their content to enable them to be used as an effective discriminator of glass type. Heitkemper et al. (96/1641) reported the use of EDXRF along with other techniques in forensic studies of product tampering concerning medical syringes and numerous items found in carbonated soft drinks.9.6. Industrial Typically industrial applications of XRF provide more papers than any other area of its use and this review period wds no exception. XRF continued to find use for the determination of various elements in fuels and related materials. Baimonda et al. (95/3408) applied the technique to the determination of trace metals in Mongolian coals using a pressed disc method. The 2.5 mm diameter discs were pressed at 2-3 tonnes prior to analysis using a combined lo9Cd isotope source coupled with a Mo X-ray tube operating at 40 kV and 10 mA with an Ag secondary target. A Si(Li) detector (resolution 170 eV at 5.9 keV) was used to measure the intensities. Coals from five regions of Mongolia were analysed and results were compared using a simple quantitative method emission-transmission methods and full fundamental parameters method.Radioisotope XRF with "Fe and 244Cm sources and a pro- portional counter detector was used by Suarez-Fernandez et al. (96/2759) for the analysis of A1,0 CaO Fe203 MnO and SiO in coal ashes and for A1203 K,O SiO and TiO in coals whilst the application of EDXRF to samples of power plant coal was discussed by Viar and colleagues from the Energy Department University Oviedo Gijon Spain (96,2771) with respect to ash determination gross calorific value and sulfur content. A different approach to coal analysis using various extractions was used by OKeefe et al.(96/543). Five coals ranging from lignite to bituminous were extracted using successively deionized water ammonium acetate solution and HCl. These were to extract elements from water soluble sites ion-exchange sites of carboxylic acid in the organic portion of the coal and the acid soluble sites respectively. The extracts were subsequently analysed by WDXRF. Knowledge of this partitioning of the elements allowed predictions of the hehav- iour of inorganic components during combustion. Nickel and vanadium were determined to detection limits of 2 pg g- and 5 pg g-' (RSD 7%) in bitumen asphaltene and oil by Civici (96/405) using EDXRF. The sample (0.01-0.02 g) was homo- genized with 1 ml of an internal standard of organic Pb (40 pg ml-' as Pb) in chloroform. A portion of this mixture was evaporated on to a mylar film leaving a thin film glued to a plastic support that fitted the sample holder.The determi- nations on the film were carried out on an experimental system incorporating a W anode X-ray tube an SrC03 pellet second- ary target (90' geometry) a Si(Li) detector and a multi- channel analyser. The measuring time was 2000 s and cali- brations were produced from synthetic standards from the organic salts of the metals either prepared in the laboratory or obtained commercially. The two calibration methods were compared. Several papers demonstrated alternative approaches to the analysis of petroleum products. Lyamina et al. (96/411) poured the sample into a plastic disc with a 15 mm diameter by 1 mm deep well covered with 70 pm thick A1 foil with a 14 mm diameter hole. Prior to pouring the viscosity of the oil was increased either by liquid N2 cooling or by mixing with eicosane.The prepared sample was then analysed normdly by XRF. Kira et al. (96/521) determined sulfur in oil basing their measurements on the ratio of the X-ray fluorescence and X-ray scattering generated in the sample by primary X-rays. A simulated standard consisted of an Mo substrate and an X-ray absorber. Sulfur was also determined (together with chloride) in used oil by Kendall et al. (96/2644). Samples were prepared by five-fold dilution in mineral spirits and presented to the spectrometer using a thin film method to overcome problems with the settling of particulates. The presence of these together with emulsified water made these determinations more difficult than in pristine oil.Results were compared with those obtained from oxygen bomb combustion followed by either IC or ICP analysis. All methods were shown to be satisfactory analytical methods for determining total sulfur and chloride in used or waste oil. The use of EDXRF for the determination of As Cd Cu Fe Hg Mn Ni Pb Se V and Zn in Nigerian fresh and weathered crude oils was reported by Olajire and Oderinde (96/2559). During the weathering period values for the deter- mined elements increased. An assessment was also made of the application of the V Ni ratio to the passive tagging of oils. A number of papers appeared related to the XRF analysis of various ores and minerals. Cornejo et al. (95/2845) determined Zn in ammoniacal ore leaching solutions using EDXRF com- prising a 30 mCi 244Cm source an Ar proportional detector and a 256-channel analyser. The samples were poured into a polyethylene cup with a 1 pm mylar window. Precipitation of basic zinc carbonate was prevented by the addition of HN03 and a detection limit of 0.05 g 1-' (relative error 1.6%) was achieved with a 600 s counting time.A method for the determination of gallium in bauxite A1 based alloys and A1 production plant residues using polyurethane foam as an extraction medium was developed by Carvalho et al. (95/3402). The materials were prepared using HF-HCl (+ H2S04 and H20 for the bauxite). After evaporation to dryness (or to SO3 fumes) dissolution in 6 mol 1-' HCl and the addition of a small excess of 0.5 mol 1-' titanium(II1) chloride solution the volume was adjusted with 6 mol 1-' HCl.Polyurethane foam (previously treated with 6 mol I-' HC1 for 30 min) was added and gallium chloride was extracted and absorbed by the foam. The foam was collected by filtration and the gallium deter- mined by XRF. A linear calibration graph over the range 0.1-2.3 pg ml-' of Ga was obtained with a detection limit of 60 ng ml-' and RSD of 1.51%. Other applications were by Youssef and El-Sakr (96/1166) to the analysis of quartz crystal Hayumbu et al. (96/1237) to the analysis of rock phosphates of different origin Islam et al. (96/2569) to the determination of trace elements in Bangladesh magnetite Srivastava et al. (96/2756) to the analysis of wolframite ore having SiO and WO as major phases Stefanova et al.(96/2764) to the analysis of Cu and S in the process of copper ore enrichment and Lu et al. (95/3845) to the determination of multi-components in mixed REE oxides and trace REE in high purity REE oxides. This latter paper went into the subject very thoroughly and covered preparation including separation and enrichment selection of optimum measurement conditions elimination of line interferences and background correction of matrix effects and the design of computer programs. The theme of REE determination was also included in one of the papers on the analysis of ceramic materials by Bhat et al. (96/498) who determined major and trace constituents in gel-grown rare earth molybdate crystals by EDXRF. Monoenergetic X-rays of 22.1 and 59.6 keV were employed for the excitation of La Mo Nd and impurities such as Fe and Zn and optimum detection efficiency was obtained for many elements.The pulverized samples were pelleted with cellulose and a fundamental parameter method was used as the matrix correction procedure. Radha Krishna and colleagues at the Hyderbad Nuclear Fuel Complex (96/299) used an X-ray spectrometric internal ratio method to determine Fe in zirconia at the range 1Opg g-' to 2500 pg g-'. Fe is a critical component in Zr alloys used for the fabrication of nuclear core components of which the zirconia is an intermediate feed material. The Fe Ka intensity was ratioed to the second order Zr Ka intensity excited at 50mA/50keV in He. Powdered Journal of Analytical Atomic Spectrometry November 1996 Vol.11 431 Rsamples were pressed on top of a H3B03 substrate. Iron-free zirconia standards were obtained by passing an acid solution of Zr over an ion exchanger where precipitation of Zr and Fe occurred. The ZrO was calcined at 750°C and reduced to < 325 mesh. In the more traditional area of ceramics Anderson et al. (95/3869) used lo9Cd excited XRF analysis for the determination of Pb from the L-lines in glazes applied to tableware and tiles. The analysis was carried out for the US Food and Drugs Administration (FDA) in Washington at the NIST reactor in Gaithersburg MD and MIT laboratories in Cambridge MA. Both facilities used Ge( Li) photon detectors and annular lo9Cd sources. The method provided a fast non- destructive analysis of areas ranging from 10 to 4mm in an attempt to relate lead content to lead leachability as measured by the 'Metal Release' leachability test.The method was able to differentiate between glazes of high and low Pb content but rather understandably Pb identification did not always relate to leachability. Fifteen other elements were also found in glazes by this technique. A comparison of ICP-AES (with Cu as internal standard) XRF and fluorine volatilization (FV)-FTIR was made by Kaiser et al. (95/4546) in the determination of Si (as SiO,) in ceramic materials. Ceramic powders and polymers were pyrolysed at about 1500°C and fused in a LiB0 /B203 flux. Refractories were heated with LiBO at 950°C. The melt was cast into a disc and analysed using an X-ray tube fitted with a 125 pm thin window.FV-FTIR was judged to be the best method with respect to the expenditure of labour and the precision of results. XRF was applied to analyse the chemical components of glaze before and after firing by Nakamichi and Satomi (96/2776) in their develop- ment of a porcelain glaze suited for low-lead acid-resistant pigments in the production of Kutani porcelain. The develop- ment of software for the automation of an XRF system to be applied to materials in the ceramic industry was outlined by Ochandio Cardo et al. (96/2723). Comparative analysis of the Si content in silicon nitride was reported by Dragoo et al. (96/2667). The techniques compared were XRF AAS ICP and DCP but insufficient data was available for a complete evaluation. As might be expected steel making generated most of the papers on metal related analysis.Two review papers both describing XRF and spark emission were presented by Koch (95/4420 and 96/1140). Also of a general nature was a paper by Wagner et al. (96/541) which applied an expert system employing fuzzy logic to assign samples to a class of materials based on a semi-quantitative XRF analysis. The database used also contained data on properties pre-treatment procedures and analytical methods to help in setting up an analytical route. A paper by Molchanova et al. (96/1178) discussed an algorithm and computer software to take account of the effect of chemical composition on the alpha corrections applied to steel analysis. Of a more esoteric nature were two papers on special aspects of steel analysis.One by Mega (96/624) described the quantitative determination of oxygen on the surface of manganese-doped steel sheet. The Ka line was analysed using a synthetic crystal yielding ten times more intensity than TlAP. Calibration samples were prepared by annealing steel sheet in a reducing H2-N2 atmosphere or an oxidizing (air) atmosphere which were analysed by chemical analysis (IR absorption). The accuracy of measurements in the range 0-1000 mg rn- was 1.6 mg m-,. Investigations of the carbide phase and matrix of non-ledeberitic high-speed steel was carried out by Richter and colleagues (95/3788) using a combination of EDXRF and AAS. Together with a computing procedure the techniques were able to partition the carbon and other elements between matrix and carbides.A rapid method for the analysis of ferro-alloys which employed a lithium tetraborate protective layer for the oxidation of the alloy in order to protect the 95% Pt-5% Au fusion dish was devised by Rutherford (96/407). The lithium tetraborate was fused in the dish at 1200"C then the sample oxidized on top of the flux at 800°C for 3 h in a flow of air through the furnace equivalent to four air changes per minute. After oxidation Li2C03 was added to the cooled sample and a further heating period at 800°C was applied for 2 1 h. The fusion was completed at 1200°C for 10 min and the melt cast into a preheated 95% Pt-5%0 Au casting dish. The contribution made by XRF to the analysis of steelmaking slags was the topic for a review by Pope (96/2590).In the field of precious metal analysis a review by Robert and Russel (95/3187) covered XRF fire assay MS AES and AAS. The appearance of two papers on the application of XRF in the analysis ofsoft drinks illustrates a further diversity of its application. Robards and Antolovitch (95/3092) described its use together with that of ICP-AES and ICP-MS in the determination of trace elements in orange juice to check its authenticity. They emphasized the need for sample handling procedures to destroy organic matter. Bao (96/392) described one such process whereby the sample was carbonized in a muffle furnace at 300 "C for 30 min the residue ground 2 g mixed with 0.5 g of cellulose and pressed into a 32 mm disc at 10 tons pressure. The elements Al Ca Cu Fe K Mg Mn Na Ni P Rb Si Sr Ti Zn and Zr were determined by XRF to an RSD of 1.1-10.5% and detection limits of between 1.1 pg 8-l (Ca) and 87 pg g-l (Na).Matrix correction was applied and results were in good agreement with those by ICP AES and AAS. As befits the current interest in 'green' matters five papers appeared relating to the application o f X R F to the analysis of waste products. Dolocevanjes (95/C4201) described its use in the determination of Cd C1 Hg Pb S and T1 in waste oil incinerated in clinker burning during cement manufacture. Calibration was from synthetics made from organometallic compounds in a base of oil and xylene. Cawley et al. (96/546) analysed and characterized water treatment sludges from elec- troplating works using XRF and XRD. A semiquantitative analysis was first carried out by XRF on a pressed pellet to establish the analytes present prior to fusion into a glass bead for quantitative analysis on a special wide range oxide Cali- bration.Sample preparation reproducibility and instrument precision trials were carried out. Waste glass was also analysed prior to disposal by James et al. (96/484) by casting a melt into a preheated graphite mould and annealing for 30 min at 500°C prior to analysis. EDXRF was used by Day and Vigil (96/382) to monitor actinide waste streams. The EDXRF was installed in a glove box for the real time determination of actinides in anion exchange eluents. XRF has been widely used in the cement and allied materials industry for a number of years. Several papers have been published in this area during the period of review.Perhaps the most interesting new development in the last few years has been combined XRF-XRD instrumentation. This is particu- larly relevant in a cement plant where both chemical and phase analysis is carried out. Using a single excitation source sample support and closely coupled X-ray optics the authors were able to perform an elemental analysis (including carbon with a specially designed monochromator) by XRF and free lime by XRD. Sulfide and S differentiation (also important for cement products) was also achieved using XRF satellite peaks. An application of this 'total cement analyser' was presented by Yellepeddi and Bonvin (96/2623). The whole process was described from analysis of raw materials and raw meal through free lime in clinkers to the cement and additives such as limestone fly-ash pozzolans and slags.The analysis of blast furnace slag by XRF was the subject of a paper by Das et al. (96/1169). Sample preparation was carried out using a double briquetting technique and analysis was performed for Al,03 CaO MgO and SiOz using both enhancement and absorption 432 R Journal of Analytical Atomic Spectrometry November 1996 Vol. 11correction coefficients. There was nothing innovative about this work simply the application of well established techniques to the analysis of a specific material type. The same can be said of the paper by Sweileh and Van Peteghem (96/355) who described an automated fusion technique for sulfide-bearing furnace slag and roaster feed followed by analysis with an end window Rh anode tube X-ray spectrometer for A1203 Co Cr Cu Fe Ni S and SO2.Although the work carried out by Schlorholtz and Dubberke (96/1185) on the determination of the fly ash content of construction materials initially seems to fall in the same category their use of XRF can be viewed with a degree of novelty. The method was based on the determi- nation of Ba and Sr in the construction material. These elements apparently are greatly enriched in Iowa fly ash (the work was carried out at the Iowa State University) so were shown to be good 'fingerprints' for the presence of fly ash and when the proper criteria were satisfied allowed for the quanti- fication of the amount of fly ash present. The method was shown to be very rapid (less than 10 min per analysis) and could easily be extended to determine many other elements when investigations into the chemical attack of Portland cement based materials were required.Using data obtained by XRF analysis Grantham (96/1184) examined a procedure for the determination of the cement content of hardened concrete. The results were examined by a simultaneous equation math- ematical approach to resolve the content of the indikidual components. An unusual approach to the analysis of concrete was taken by Dhir et al. (96/2656). A modified use of the thin film technique to the analysis of solution extracts from concrete was developed and tested. Small volumes of the solutions were evaporated onto suitably machined copper disks to yield a thin film of evaporated salts which is virtually free from absorption effects and was analysed by XRF for sulfate and chloride ions in solution.Requirements for specialized control techniques when secondary materials such as unknown raw materials and fuels are used in cement manufacture were described by Gerger (96/2560). The use of XRF for regular measurements of trace elements in secondary fuels was reported. Finally since process control and automation are extremely important issues in the cement industry various papers con- cerned with this topic were published. The one by Price (96/539) described new developments in the use of XRF for the analysis of cement making materials in production control. Roelver (96/533) and Triebel (96/1224) both described uses of the POLAB laboratory automation system in cement works.This system includes modern robotic technology for automatic sampling and sample preparation X-ray fluorescence analysis laser granulometry and colour analysis. Field and Hornung (96/2604) and Fleming and Jefferson (96/2651) both reported on the advances in benchtop EDXRF with particular emphasis on the determination of light elements and the application to process control in cement manufacture. The use of XRF for the analysis of inorganic constituents in plastics and rubbers is becoming more widespread. Metz et al. (95/3411) carried out an interesting comparative study of EDXRF techniques (with and without polarized radiation) and a wavelength dispersive technique for the trace determination of transition metals in plastic materials.Liquid calibration samples were prepared in paraffin oil for the elements Co Cr Cu Mn and Ni. Calibration lines in the concentration range 1-100 pg g-' were evaluated for a number of commercially available XRF instruments. Limits of detection ranging from 0.1 to 0.7 pg g-' for WDXRF and EDXRF with polarized radiation and from 0.9 to 8.6 pg g-' for EDXRF without polarized radiation were reported. The application of the methods to the study of wear and corrosion were discussed. Figura and Osae (95/3493) used XRF analysis in a He environ- ment to determine the total chlorine in di-isocyanates (used in the manufacture of polyurethanes). Analysis was carried out by spiking with monochlorobenzene using the C1 Ka line. A detection limit of 5 pg g-' was obtained (considerably lower than the 1OOpg g-' obtained by use of an oxygen bomb).It was also noted that the presence of Br which can effect oxygen bomb analysis did not effect XRF analysis. Necemer and Kump (95/C4203) showed that XRF could be used for the elemental content of rubber either vulcanized or pulverized by liquid nitrogen. A review of XRF using new low-cost equipment and methodologies for the multi-element analysis of polymers was published by Bruna (96/2663). Theoretical principles instrumentation limitations of the technique elemental analysis of polyethylene and polypropylene com- posites determination of C1 Ca and Pb in PVC formulation and determination of C1 in epoxy resins were all topics of discussion. An XRF technique for the analysis ofjllers in paper was described by Kocman and Bruno (96/1165).The levels of fillers such as kaolinite calcium carbonate titanium(rv) oxide talc muscovite and sodium aluminosilicate in commercial fine papers newsprint decorative papers coated offsets and head- box furnish were derived individually from elemental analysis and established according to stoichiometric conditions calcu- lated and verified by a small software program. A review of the use of EDXRF in the analysis of paper and wood fibre was presented by Silveira and Conners (96/2770). XRF was utilized for light element analysis in silicone grease by Untenecker et al. (96/1177). The silicone grease was squeezed directly into a liquid cell (avoiding bubbles) and covered with 2.5 pm mylar film. Analysis for C1 and S was carried out with helium as a sheath gas to avoid formation of gas bubbles or spattering in vacuum operation.Although the use of helium and mylar film reduced intensities by approxi- mately 25% detection limits of 100 pg g-' were achieved with a PET analysing crystal. The determination of fluorine was also attempted under the same conditions with a multilayer 'crystal' resulted in a 90-95% loss in intensity. A detection limit of 500 pg g-' was achieved by smearing on a filter paper and measuring in vacuum. A patent claim for the XRF determination of noble metal content in electrodes was received from Sad0 of the Fuji Electric Company Japan (96/2666). The method for the fast determination of metals such as Pt and Ru in catalyst film on a carbon electrode comprised irradiating the sample with X-rays and determining the metal content by XRF. It is difficult from the details given in the abstract to understand what is actually patentable in this method.These and other industrial applications were reviewed in the latest ASU update (96/416). A specialized history and review of the industrial applications of X-rays was published by Kobayashi (96/2757). A comparison of energy and wavelength XRF spectrometers for industrial process analysis and control (particularly in the steel and cement sectors) was given in a review by Price et al. (96/2725). An evaluation of a commercial instrument was reported by Uhlig and Mueller (96/519) with particular reference to the determination of Pb in petroleum F in oils and greases and the analysis of waste waters.9.7. Clinical and Biological Once again a predominant focus of interest was the determi- nation of lead in bone. Of great interest to the medical profession will be a final report published by Rosen (96/1207) which showed the unique capability of XRF for the safe accurate and non-invasive quantification of lead in bone in children. Blood lead screening only reflects recent exposure whereas bone lead gives an indication of ongoing accumulation. The report demonstrated the use of the L-line XRF technique and findings indicated how the method represented an Journal of Analytical Atomic Spectrometry November 1996 Vol. 1 1 433Rimportant approach towards incorporation into clinical treat- ment protocols. In a report by Bleecker et al. (96/603) the relationship between bone lead and other indices of lead exposure was examined by reference to a group 81 smelter workers.Lead exposure had changed dramatically over the 27 year history of the smelter so the workers were chosen accord- ing to years of employment. Bone lead was measured in the mid tibia by K-line XRF. Results reported showed a significant relationship between bone lead and blood lead indexes. Similarly Roels et al. (96/2782) measured lead in vivo in the tibia of workers from a primary lead smelter during a study to estimate cumulative lead dose. A '09Cd Pb K-line XRF technique was utilized. To illustrate further the growing impor- tance of this particular application yet another study reported by Cake et al. (96/2787) used Pb K-lines to measure tibial lead in workers at a lead recycling plant.Both these latter studies showed good correlation between lead bone measure- ments and cumulative blood level index and showed that bone lead measured in this way was a valid measurement for cumulative exposure. A clinical application of in vivo tibial K-XRF was also reported by Wedeen et al. (96/2648) to study cumulative lead storing in patients. Four situations were examined ( 1) post-chelation therapy (2) renal failure (3) home exposure and (4) occupational exposure. Examples dis- cussed showed how physicians can use the technique to give valuable information for patient management and how because of its safety specificity and simplicity it should make an alternative to cumbersome chelation tests and potentially misleading blood level measurements.The relationship between bone lead concentration and a number of variables including environment and lifestyle was evaluated by Ryde et al. (96/2788). Age was found to contribute the strongest influence followed by water lead smoking dust and blood lead levels. The development of bone lead reference materials for validating in vivo XRF measurements was described by Parsons et al. (96/2783). Bone samples were collected from nine goats and one cow which had been dosed with lead over a period of time (1-10 years). Prior to this the only reference materials available were from NIST (SRM1486 bone meal at 1.335 pg g-' and SRM 1400 bone ash at 9.07 pg g-'). Both were useful in validating other techniques for bone lead (e.g. GFAAS) but were too low to be of practicaluse for in vivo XRF.The bone samples collected were reduced to small pieces freeze dried and homogenized in a tantalum ball mill whereupon the bone powders were microwave digested in nitric acid. Determinations were carried out using GFAAS with Zeeman background correction producing a detection limit of 0.6 pg g-' (based on 3 standard deviations) and a range of standards from 5-50 pg dry mass. This adequately covered the clinical range likely to be encountered. Two papers were published showing the important emergence of XRF in measuring bone lead as the basis for epidemiological studies. Hu et a!. (96/536) reported on the technique but more importantly discussed important areas where validity of data may be an issue. The same group of authors together with additional co-workers (96/1179) reported on a study to improve the determination of low-level bone lead concentrations using K-line XRF.Aro et al. (96/467) evaluated the suitability of plaster-of-Paris phantoms as targets for inter-calibration standards in the measurement of bone lead using a lo9Cd K-line XRF system. The XRF system was compared with a commercial bone lead measuring system and demonstrated better precision in the analysis of phantoms in both air and water. The authors recommended that the plaster-of-Paris phantoms should first be analysed by ICP-MS or another valid technique before being used to calibrate K-line XRF. Bhattacharyya et al. (96/1188) used XRF to make in vivo measurements of blood lead and bone lead in US army artillerymen in a study to examine if Pb exposure were greater in artillerymen than in control servicemen or whether there was any correlation with length of service.Early termination of the project resulted in under-achieved group sizes but results showed Pb exposure was low in all study subjects showing no significant difference in personnel category or in length of service. A number of reviews relating to in vivo lead measurements have been documented. Rosen (96/2784) discussed the develop- ment of L-line XRF instrumentation and its use in the esti- mation of bone lead values. Current instrument design and planned future refinements were also included together with clinical case studies. Similarly Chettle (96/2789) outlined the techniques for in v i m XRF measurement for lead and other heavy metals. A second review by the same author (96/2575) referred to metd intoxication in humans.Although making reference to bone lead this contribution was more of a general clinical nature. XRF was amongst the techniques used by Gerhardsson et al. (96/2785) in a lead toxicity study of deceased lead smelter workers. Smelter workers were exposed to a number of metals and other substances in dust fumes and gases. Lead concen- trations in liver lung kidney brain hair and nails were determined in 32 deceased long-term exposed male workers with 10 male controls. The highest lead levels in soft tissues for both groups were found in the liver followed in order of concentration by kidney lung and brain but concentrations were significantly higher in the worker group (the largest difference being the brain tissue).Lead levels in hair and nails were of the same magnitude in the two groups. Much work has been carried out over the years on the determination of minor and trace elements in human hair. Sample collection is very easy and non-invasive compared with sampling living tissue. Over the current review period four papers have been reported in this area. In the first Basco and Uzonyi (96/406) investigated the heterogeneity effects of Ca C1 K and S (all biologically important elements) using an Si(Li) EDXRF spectrometer of 170 eV energy resolution (FWHM) at 5.9 keV energy. Measurements were taken using bunches of hair strands and pelletized hair samples. Differences of ~ 5 % for Ca and 10-15% for C1 K and S were reported in the two types but were regarded to be negligible compared with the biological variability or effect measured. Following a tragic case of mercury poisoning Toribara (96/381) reported on the building of a special EDXRF system to determine the concentration of mercury in a 1 mm segment of a single hair.The advantages of XRF analysis for heavy metals along the length of single hair over bulk analysis were discussed in particular their relevance in the study of the temporal course of heavy metal poisoning or of change of life-style or diet. Tsang et a!. (96/2763) used XRF to study trace elements in the hair of Chinese diabetic patients and showed a higher level of iron in diabetic subjects when compared with controls. EDXRF was one of several techniques used by Cargnello and colleagues at St.Thomas Hospital London (95/3110) in the development of a method to differentiate trace elements within hair from external surface contamination and to analyse accu- rately the elemental cross sections of hair. EDXRF was the method used by Mwaura et al. (96/466) as a simple way to determine iodine in urine and water samples. After digestion with chromic acid iodate was converted to iodide with strong sodium sulfite solution and palladium iodide precipitated with palladium chloride. The precipitate was filtered through a membrane filter paper air dried and analysed using EDXRF. Boerjesson et al. (96/138 and 96/2786) also used XRF for the analysis of mercury in a study to show the relationship between concentrations in the kidney and the urine.They measured mercury levels in the kidney liver and thyroid (using a technique based on excitation with partly plane-polarized photons) on a group of twenty mercury- exposed workers and 12 occupationally unexposed ones. 434 R Journal of Analytical Atomic Spectrometry November 1996 Vol. 11Mercury levels in blood and urine were also measured by AAS. The mean kidney mercury concentration was reported as 24 pg g-' in the exposed workers and 1 pg g-' in the unexposed while measurements on the liver and thyroid of exposed workers were below the detection limit. The mean urinary mercury excretions for the two groups were 34 and 1.7 pg per gram of creatinine. They concluded that the relation- ship between Hg in the kidney and urine was significant but were unclear whether it was linear.An XRF technique using plane-polarized X-rays for excitation was used by Nilsson et al. (96/2647) for in vivo measurement of Cd in the kidney cortex among non-occupationally exposed people in southern Sweden. They showed that levels for smokers (median 28 pg g-') were significantly higher when compared with non- smokers (median 8 pg g-') as were levels in blood and urine. Other clinical applications of XRF were reported by MacLean et al. (96/571) who demonstrated the feasibility of using radioisotope induced XRF analysis of I as a non-invasive method to measure the release rate of peptides/proteins from hydrogels or other formulations in vivo following subcutaneous administration. Szluha et al. (96/495) used EDXRF for the determination of Pt in biopsy tissue taken from cervical cancer patients after intra-arterial and intra-venal administration of cisplatin.The distribution of Pt within the tumour and its proximity was studied. In vivo measurements of Pt are import- ant for studying the pharmacokinetics of platinum-based cyto- xic drugs and another use of XRF for this application was demonstrated by Ogg et al. (96/432) in their investigation into the feasibility of using 133Xe in near-backscatter (almost 180") geometry. Raggi et al. (96/2761) described a very simple and rapid XRF method carried out on solid pharmaceutical samples of suitable diameter and thickness on a boric acid support for the determination of selenium in diet supplement. A different contribution to in vivo analysis was made by Zaichick et al.(96/2780) in their work on frontal tooth enamel. An XRF method using an annular Io9Cd source with about 2.5 GBq activity and a Si(Li) detector was developed for the determination of Ca Pb Sr and Zn. Only a 7mm diameter spot of a tooth was examined the rest of the tissues and organs of the face and mouth cavity being safely protected from radiation. The method was found suitable for incisors canines and premolars of maxella and mandible. Reproducibility for repeated tests in human volunteers was not less than 3% for Ca and Sr and 10% for Zn with analysis times of 2 and 5 min respectively. Analysis of milk and second teeth of 50 children and adult citizens of Obninsk showed that the Sr content in caries-resistant teeth was significantly higher than in caries- affected ones.Pb concentrations of all people examined did not exceed a 3 pg g-' detection limit. A non-invasive XRF technique was developed by Bloch (96/2779) to assay depleted uranium in bones in-situ. Occupational exposure to uranium associated with milling and fabrication of depleted uranium is traditionally measured from the bioassay of urine. Unfortunately evaluation of the body burden of uranium from urine measurements has many difficulties and uncertainties due to biotransport of inhaled uranium particles from the lungs to absorption in the blood and excretion through the kidneys. Although the toxicity of transuranium elements is not fully understood they are known to be deposited and retained in bone hence this development.K shell electrons in urmium (binding energy of 115.6 keV) were excited by the 122 and 136 keV gamma rays from a 57C0 source and measured by a liquid nitrogen cooled intrinsic Ge detector together with the coherently scattered gamma rays from the 57C0. The quantity of uranium in the bone was determined from the number of K fluorescence events extracted from the measured scattered photon spectrum. Additionally the bone mineral mass was determined from the number of coherently scattered gamma rays permitting the assay to be expressed in terms of micro- grams per unit mass of bone. The method made it possible to measure molar concentrations of uranium with high precision and reproducibility. Conversely Shea et al. (96/2758) demon- strated that EDXRF was not a feasible technique for the detection of catalysis elements from polyethylene in histology specimens. Lewis and colleagues at the University of Wales (96/2781) reported the application of the EGS4 Monte Carlo code to the design of a polarized source for in vivo XRF analysis of Pt.Results were used to evaluate the selection of polarizer material secondary beam collimator geometry and the effect of beam polarization in scatter reduction. A method for the trace element determination in biological materials was the subject of a patent claim by Sayama and colleagues from the Mitsubishi Materials Corporation Japan (95/2573). The method described consisted of treating human serum (500 pl) with 500 p1 of HF dropping onto Si wafer chip drying and irradiating with X-rays at 40 kV/5 mA.Elements of interest were Ca Cu Fe Pt Pb and Zn. A number of XRF method reviews were also published. Robertson and Jay (96/1194) described an XRF experimental system and discussed drug percutaneous absorption measure- ments. Boerjesson and Mattsson (96/623) reviewed XRF tech- niques developed for the measurement of Cd Hg and Pb primarily in occupationally exposed workers. EDXRF was compared with stripping potentiometry (SP) for the determi- nation of Cu levels in human serum by Viksna et al. (96/535). Similarly Kim and Nikolaev (96/1136) investigated various methods including XRF for the determination of the iron content in pharmaceuticals. The data produced was used to revise and create technical documentation for pharmaceutical production.A review including the chemical biological and environmental properties of lead isotopic composition of lead and measurement methodologies (inclusive of XRF) was pre- pared by Flegal and Smith (96/2649) in respect of environmen- tal lead contamination and human exposure. Covered was the use of in-situ methods and measurements of human lead exposure and toxicity including stable lead isotopic tracers in metabolic studies biological markers of lead toxicity and biomedical speciation of lead. In the area of animal experiments Shenberg et al. (96/534) studied the Br Rb ratio in the kidneys of healthy and tumour- bearing mice. The mice were treated with cis-DDP with and without selenite with selenite alone and compared with con- trols. The mice were killed 7 14 and 21-28 d after treatment and their kidneys subjected to Br and Rb determination by what was claimed to be a 'novel' XRF method.The authors observed that the Br Rb ratio was 2-4 times higher in normal than in malignant tissue. Singh et al. (95/4490) used EDXRF to examine the distribution of Br Cu Fe K Rb and Zn in whole brain samples following the administration of combined Pb and Li to female Porton rats. They noted that Cu K and Rb levels were diminished whereas Fe and Br levels were enhanced following short and long term treatment. The Zn levels were lowered following the treatment for short term only. After injection into male Wistar rats the dissolution of man-made vitreous fibre samples (glass wool rock wool and glass microfibres JM100) was studied by Wastiaux et al.(95/4042). Urine collected at fixed times between 1 and 204 d was examined by ICP for the elements known to be present in the original fibres. At day 204 a piece of omentum (taken at autopsy) was ashed and analysed by EDXRF to identify the elements remaining in the fibres. Following detailed study of the results the authors considered that Ti and Ba could be suitable biomarkers of exposure to rock wool and glass microfibres. Biological materials relating to plants and soil were studied by several groups. Haneklaus et al. (96/584) compared plant sulfur analysis with soil sulfur analysis by XRF for their suitability in evaluating the nutritional status of oilseed rape Journal of Analytical Atomic Spectrometry November 1996 Vol. 11 435 Rand winter wheat.The soil sulfur contents measured did not correlate with plant S content. Interactions between soil water and mobile S fractions within the soils were postulated as the cause for the poor correlation. Vecchi et al. (96/453) used EDXRF as a biomonitoring exercise on a group of mosses in the Italian Alps. The fundamental parameter method used with a rhodium-tube fully automated sequential X-ray spec- trometer formed the basis of a paper by Omote et al. (96/303) where the elemental composition of plant samples was deter- mined. Quantitative analysis was carried out for Al Ca Fe K Mg and P on 14 samples of moor vegetation using four calibration samples prepared by spiking cellulose powder with standard metal solutions. The distribution of Ca C1 K and S along the profiles of two soils (red yellow podzolic and dark red latosol) treated with vinasse was studied using EDXRF by Simabuco and Filho (96/526).A significant increase in concentration was observed and a similar effect noted when Cu Rb Sr and Zn were determined. In contrast Al Fe Mn Si Ti and Zr showed no significant variation because of the high initial soil concentration of these elements compared to the low concentration in the vinasse. Annular sources of "Fe and '"Cd were used for excitation and a Si( Li) semiconductor for detection coupled to a multi-element emulation card in a microcomputer. Marsh soil from four habitats of a NE Hungarian peatland were examined by Braun et al. (96/1252) using both EDXRF and ICP-AES for Fe and Mn as major and Nb Sr Y and Zn as minor elements.Sample pretreatment was carried out by three different methods and all data collected were compared by principal component analysis. EDXRF and ICP-AES were also compared using different preparative techniques by Desmarais et al. (95/3976) in a study of 11 bryophote species from peatlands in the Athabasca Alberta Canada. Al Ca Cu Fe K Mg Mn Na P Pb S and Zn were measured in six sphagnum species and five other Bryophote genera together with surface water obtained from the sampled peatlands. Improvements in instrument method- ology were demonstrated by Bonvin and colleagues (96/2775) in their paper introducing a new multilayer crystal and detector window for the analysis of nitrogen (and other elements) in plant material. Although very fast (and not restricted to nitrogen) compared with techniques such as Kjeldahl or com- bustion analysis the quoted standard error of estimation (0.25%) means that accuracy and precision are not as high.The pros and cons of XRF for the analysis of lichens used in pollution monitoring studies was examined by Richardson et al. (96/2660). Haneklaus et al. (96/2577) reported on a study involving the analysis of Rb in soils by XRF; Jopke et al. (96/2576) referred to XRF as one of the techniques used in the method development for the determination of iodine in plants and soils; Wathelet et al. (96/2661) reported that XRF could be used instead of the recommended HPLC for the fast measurement of glucosinolates in rapeseed and Li and Fan (96/2662) developed a pressed powder pellet technique (based on 1 g of dry powdered material) using scattered line as an internal standard to correct for interelement effects for the direct determination of 25 elements in plant material.Other biological applications included Yang et al. (96/452) who measured Ca Ce Fe Mn and Zn in tea leaves using an EDXRF system made in China. They ashed the tea leaves and used Y as an internal standard. Very good results were claimed. Fernandes et al. (96/1134) used the determination of Al Fe Si Ti and Zr by EDXRF in ten soils from the sugar cane growing area of Sao Paulo Brazil to establish a method to characterize soils in shredded cane. The elemental ratios Fe Si and Fe (Si + Al) were shown to be useful for measurements of soil in cane. Wartelle et al. (96/537) demonstrated that EDXRF (Rh tube with Ti secondary target) could be used as a simple method for determining cotton fibre maturity.This is an important factor in cotton classification and fibre and textile processing. Since it was hypothesized that during fibre matu- ration structural calcium in the primary wall is diluted by the development of the highly cellulosic secondary wall the method involved simply the measurement of calcium. The analysis was carried out on a ground sample of 2 100 mg pressed for 20 s at 20 kpsi into a 31 mm diameter pellet. NIST SRM Apple Leaves diluted with cellulose powder were used as standards. A detection limit of 6 pg 8-l was obtained and good correlation shown with results by ICP. A monitoring survey was carried out by Calliari et al.(96/604) in Northern Italy using a specified lichen as a monitor of air pollution. Experiments were carried out on lichen exposed for varying periods (3-10 months) both in urban and rural locations to compare the bio-accumulation of several elements. At 2 month intervals a fraction of exposed lichens was collected and divided into two one of which was washed in deionized water to quantify the element loss due to washing and then analysed by EDXRF in the secondary excitation mode. The fundamental parameter method was used with NIST reference materials. The samples were prepared by digestion under pressure with microwave heating. The survey demonstrated that all elements showed higher concentrations at the urban than at the rural sites. A brief assessment of methodology (including XRF) and laboratory performance in the analysis of biological reference materials was presented by Ihnat (96/1572); performance par- ameters included within and between laboratory precision accuracy (bias) elemental applicability and matrix effects.An extended review of applications to other clinical and biological materials can be found in the current ASU update (96/2479). 9.8. Thin Films A very comprehensive review of glancing-incidence X-ray analysis (GIXA) was presented by de Boer et al. (96/987 and 96/422). During the past years this technique has developed to maturity and is well founded on theoretical grounds not least due to many contributions from these authors. This analytical method is well suited for the non-destructive analysis of thin films and multilayers layer thicknesses their comp- osition the quality (roughness) of the interfaces and to some extent depth profiles can be determined by reflectivity and fluorescence measurements. With a slightly different mathematical approach but equival- ent conclusions Mantler and colleagues (96/574) described multilayer thin films using fundamental parameters in order to specify their thicknesses and element content. Experimental results acquired with a wavelength dispersive system and incidence angles above the critical angles for the respective layers were presented for samples with up to 80 layers.The work of Tsuji et al. was devoted to the determination of depth profiles in Au-Si interfaces (96/2610) and the charac- terization of surfaces and interfaces applied to Ni/Mn multi- layers (96/2797) under glancing-incidence and glancing-take-of conditions with the motivation that variations of the two angles change the effective observation depth and therefore enable non-destructive depth profiling.Roberts and Gray (96/1138) claimed for the first time the nondestructive real-time analysis of growing films. Their tech- niques could be a valuable processing probe for multilayer film deposition. The simultaneous analysis of total reflection X-ray diffraction and fluorescence by Hayashi et al. (96/2795) of copper phthalocyanine thin films during evaporation processes gave valuable insights specifically the exact change in molecu- lar orientation with increase in film thickness. Harlan and Comtois (96/1111) described the design criteria of a process control instrument (energy dispersive detector) that could be placed inside a vacuum chamber under coating conditions.A lightweight mobile probe with a state-of-the-art HgI detector 436 R Journal of Analytical Atomic Spectrometry November 1996 Vol. 11was used to determine the variability of adhesion promoter film thickness with Ti added to the substrate and Cr to the film as tagging elements (96/544). An on-line Si coating weight gauge as used for adhesive paper production was described (96/1176). Ebel et al. (96/578) determined Jilm thicknesses by the variation of the incidence angle and used polychromatic pri- mary radiation of a rotating anode system for excitation. For the determination of the composition a monochromator had been inserted into the primary beam path.Also the most powerful instrument for sample excitation namely a synchro- tron radiation source (ELSA Germany) was found to be an appropriate means for film thickness determinations of Au on Si Cr on Si02 and TiO on alkali-free glass (96/1148). Depth profiles of a Cu/Cr multilayer were determined by means of the combination of total reflection XRF (TXRF) with low-energy ion beam etching as a destructive sample preparation technique (95/4580). Arai et al. improved the precision for the determination of B in thin boron-doped phosphor silicate glass (96/576) and studied spurious peaks and other effects as observed with a commercially available wafer analyser (96/2739). The effect of surface roughness of the substrate for the characterization of thin films by take-off angle dependent XRF was investigated (96/628 and 96/447) with the conclusion that a substrate with a well defined roughness might be advantageous for this technique.Several other application oriented publications like Sn/Pb layers (96/2595) gold platings (96/602) Pb/Zr/Ti thin films as gen- erated by co-sputtering and annealing processes (96/1124) P-doped A1 oxide films (96/1353) multimetal multilayer films as found in semiconductor manufacturing (96/606) and a review by Huang et al. (96/1152) of XRF and reflectivity measurements as complementary techniques demonstrate the vital role of XRF in the analysis of thin films. 9.9. Chemical State Analysis Kawai and co-workers remain very active in this area of research and Kawai (96/527) himself reviewed comprehensively the various approximations used to calculate the change in peak profiles with chemical environments which occur in XRF spectrometric studies.A two-crystal spectrometer equipped with indium antimon- ide crystals was used to investigate chemical effects on the Si KP peak in silicates and silicophosphates (96/501). The ineas- ured peak positions and relative peak intensities showed good agreement with calculations using Slater’s transition state method and the observed Si KP peak shifts were discussed in terms of differences in the second-nearest-neighbour patterns specifically the effect of the second-nearest-neighbour P atoms on the stability of the Si-0 bond. Murty et al. (96/473) reported measured differences in the relative intensity of the Si Ka satellite between Si in silicon and in Si02. By using a high resolution two-crystal vacuum Spectrometer fitted with Ge( 11 1) crystals Sugiura (96/589) investigated chemical effects on the K series spectrum of phosphorus in 10 0x0-acids.A weak peak on the high energy side of the P KP peak was related to the molecular orbital t2 symmetry i n the phosphate ion. In a further study (96/2563) the P KP and S KP emission spectra from eight phosphorus and 20 sulfur compounds were investigated. Molecular orbital calculations of PF,- and sulfur 0x0-anions were used in the interpretation of the measured spectrum. The KP spectra were found to be strongly influenced by the chemical environment immediately around the P and S atoms but little affected by the metal cations Naf or K +.In a study of the S KP emission spectrum Ji et al. (96/2637) found the Kfi peak from FeS to be a singlet while that from NH2CSNH2 was a resolved doublet and pure sulfur gave a broad single peak which the authors considered to be an unresolved doublet. The chemical state of sulfur in oxyanions was distinguished by studying the peak shifts in the resolved KP peaks. Kawai and co-workers (96/434) measured the line width of the Fe Ka peak from the three oxides and two cyanide compounds of iron. The line width was almost identical in the oxides which was shown to be contrary to Van Vleck’s theorem. It was concluded from molecular orbital calculations that in the case of the oxides the charge transfer effect induced by the creation of the 1 s-l hole in the core of the atom (which is the initial state just prior to Ka-line emission) reduces the effective number of un-paired 3d electrons and results in a reduction of the Fe Ka peak width.Conversely the authors confirmed that Van Vleck’s theorem held for the cyanide complexes investigated. A careful study of the Cu K spectrum by Deutsch et al. (96/481) involving ab initio molecu- lar orbital calculations revealed that the line shape can be accounted for by considering only the diagram line and the single 3d spectator hole transition. Small systematic deviations between the observed and calculated KP peak were attributed to exchange interactions or plasmon excitations. Such devi- ations were absent for the Ka peak. The chemical effect on the relative intensity of the K-line series X-rays of Cr Mn and V was studied by Tamaki (96/998). The intensities of each of the Kfi1.3 KP2 K P and K F lines relative to that of the Ka line were determined using an Si( Li) detector which was itself unable to resolve the individual KB lines.Line shapes and peak shifts were documented for the K series lines in four V and eight each Cr and Mn compounds. Peak shifts of up to -3.7 eV (Mn30,) were observed and the relative importance of the increase in transition probability of the KP2 and KP’’ lines on the observed KP/Ka ratio was determined. Chang et al. (96/444) also used an Si(Li) detector to investigate KP/Ka intensity ratios for seven vanadium compounds. The highest KP/Ka ratios were observed for compounds with the most covalent character and this was attributed to an increase in the intensity of non-diagram lines due to band mixing between the metal and ligand.Intensity ratios (KP/Ka) for elements in the atomic number range 15-22 (P-Ti) were reported by Zararsiz (96/454) who used an ”Fe source and Si( Li) detector. A study of the L spectrum of Nb by Iihara and Yoshihara (96/435) revealed that the Ly spectra of metallic niobium and Nb-Ni amorphous alloys showed only one broad peak while those of NbC and NbN had two peaks. The broadening of the Nb Ly peak in amorphous alloys compared with metallic niobium was attributed to the formation a mixed molecular orbital of Nb-4d and Ni-3d electrons. A polemic on the relationship between Cu L XRF and Cu 2p XPS data and the interpretation of these spectra was exchanged between Kawai et al.(96/1142) and Ohno (96/1139). A novel instrument incorporating an X-ray microcalorimeter detector with an energy resolution of 20 eV was used to study the intra-series ratios in Ar K spectra by Le Gros et al. (96/514). The KP,y Ka ratio from highly charged Ar ions was found to differ by a factor of four from that observed in neutral atoms. Artemiev and co-workers (95/4567) proposed a design for a spectrometer specifically for chemical shift measurements using SR excitation. Jourrial of qnalytical Atomic Spectrometry November 1996 Vol. 11 437 RLOCATION OF REFERENCES The full list of references cited in this Update have been published as follows 95/1160-95/1597 J. Anal. At. Spectrom. 1995 10(6) 155R-171R.95/1598-95/C2275 J. Anal. At. Spectrom. 1995 10( 7) 173R-198R. 9512276-95/2891 J. Anal. At. Spectrom. 1995 10(8) 229R-251R. 95/C2892-95/3361 J. Anal. At. Spectrom. 1995 10( lo) 31 1R-328R. 9513362-95/4189 J. Anal. At. Spectrom. 1995 10( 1 l) 329R-358R. 95/C4190-95/4746 J. Anal. At. Spectrom. 1995 10( 12) 402R-422R. 96/C1-96/416 J. Anal. At. Spectrom. 1996 11( l ) 1R-17R. 96/417-96/C947 J. Anal. At. Spectrom. 1996 11(2) 67R-85R. 96/948-96/1357 J. Anal. At. Spectrom. 1996 11( 3) 87R-101R. 96/1358-96/1802 J. Anal. At. Spectrom. 1996 11(4) 187R-203R. 96/1803-96/2015 J. Anal. At. Spectrom. 1996 11( 5 ) 205R-212R. 96/2016-96/2799 J. Anal. At. Spectrom. 1996 11( 6) 239R-269R. Abbreviated forms of the literature references quoted (excluding those to Conference Proceedings) are given on the following pages for the convenience of the readers.The full references names and addresses of the authors and details of the Conference presentations can be found in the appropriate issues of JAAS cited above. Abbreviated List of References Cited in Update 95/1153 J. Environ. Qual. 1993 22 851. 95/2297 X-Ray Spectrom. 1994,23 208. 95/2493 Nucl. 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ISSN:0267-9477    

DOI:10.1039/JA996110409R

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

96/C4 16 1 96/C4162 96/C4163 96/C4 164 96/C4 165 96/C4 166 96/C4 167 96/C4 168 96/C4169 96/C4170 96/C417 1 96/C4172 Karanassios V. Drouin P. Kellerman R. Two- dimension cross-correlation signal processing in ICP- AES with a charge injection device area sensor detector. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Waterloo Waterloo Ontario Canada N2L 3G1). Karanassios V. Willeke M. Zhang Z. A spark sample introduction system for inductively coupled plasma atomic emission spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Waterloo Waterloo Ontario Canada N2L 3G1). Lee S.-c. Shin J.-s. Kang M.-r. Lee S. C. Trace metal analyses of kiwis by use of hollow cathode glow discharge atomic emission spectrometer.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Food Eng. Kyungnam Univ. Masan South Korea). Lee S. C. Song K. S. Cha H. G. Lee J. M. Lipert R. J. Edelson M. C. Characterization of hollow cathode glow discharge laser excited atomic fluorescence spectrometry (HCGD-LEAFS). Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Kyungnam Univ. Masan South Korea). Yokhin B. A high resolution transportable EDX KF SI spectrometer for laboratory and field applications. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Jordan Valley AR Inc. h1igdal Haemek 23100 Israel). Winchester M. R. Salit M. K. Macro-scale elemental composition mapping of solid surfaces through glow discharge optical emission spectrometry.Pitts lburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Anal. Chem. Div. Chem. Sci. and Technol. Lab. Natl. Inst. Stand. Technol. Gaithersburg. MD 20899 USA). Guan S. Marshall A. G. Linear prediction time- domain data analysis for ion cyclotron resonance mass spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (('enter Interdisciplinary Magnetic Resonance Natl. High Magnetic Field Lab. Florida State Univ. Tallahmee FL 32310 USA). Bo D. Guoan L. Xiaoyi G. Determination of As(v) and AS@) using spectrophotometry combined with forward artificial neural network. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Tsinghua Univ. Beijing 100084 China). Haesselbarth W. Sampling plans for testing unceri ainty in chemical analysis.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8,1996 (Bundesanstalt Mater. und -pruefung (BAM) D-12200 Berlin Germany). Hughes A. Wiedenmann L. Weiss A. D. Mer-cury determination in dental waste samples by amalgam ICP-MS and gold standard addition ICP-MS. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Hazardous Waste Res. and Inf. Center Champaign IL 61820 USA). Lu B. The study on direct determination of 46 impurity dements in high purity metal scandium by ICP- 4ES. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Nanjing Inst. Geol. and Miner. Resour. Nanjing 210016 China). Dobb D. E. Heitschmidt J. Ottmar L. J. Hall T. M. Hillman D. C. Comparison of radial- and axial- viewed ICP-AES instruments for the determination of 96/C4173 96/C4 174 96/C4175 96/C4176 96/C4177 96/C4178 96/C4179 96/C4180 96/C418 1 96/C4182 As Pb Se and T1 in environmental samples.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Lockheed Environ. Systems & Technol. Co. Las Vegas NV 89119-3705 USA). Grebneva 0. N. Kubrakova I. V. Kuzimin N. M. ICP-AES and ETAAS determination of trace elements in high-purity oxides after microwave dissolution. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Vernadsky Inst. Geochem. and Anal. Chem. Russian Acad. Sci. Moscow 117975 Russia). Starshinova N. P. Skalny A. V. Sedykh E. M. Medical diagnostics based on the results of AES-ICP analysis of human hair. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Vernadsky Inst.Geochem. and Anal. Chem. Acad. Sci. 117975 Moscow Russia). Tian L.-c. Zhao P.-d. Feng Y.4. Hydride reduction kinetics of antimony(v) by L-cysteine and a small co-centre generator with ICP-AES. I. Simultaneous determination of antimony(v) and antimony(II1) in environmental sample. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Center Mater. Anal. Nanjing Univ. Nanjing 210009 China). Butcher D. J. Lee C. E. Cox J. M. Foster D. M. Humphrey H. L. Woosley R. S. Determination of calcium magnesium and aluminium by flame and graphite furnace atomic absorption spectrometry in Fraser fir (Abies fraseri) foliage from Clingman's Dome NC Roan Mountain NC and Mount Rogers VA. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept.Chem. and Phys. Western Carolina Univ. Cullowhee NC 28723 USA). Sedykh E. Bannykh L. Electrothermal atomic absorp- tion determination of Se in food products. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Vernadsky Inst. Geochem. and Anal. Chem. Acad. Sci. 117975 Moscow Russia). Gornushkin I. B. Smith B. W. Winefordner J. D. Use of a furnace with a graphite filter for the direct determination of ultra-trace amounts of elements in liquid and solid samples by laser excited atomic fluorescence spectrometry (LEAFS). Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Florida Gainesville FL Chapon P. Optimized accuracy in a global calibration of steels and cast irons.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Instrum. S.A. Div. Jobin Yvon 91 165 Longjumeau France). Chapon P. Tournarie D. On-line control and diagnos- tic of spark instrument. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Instrum. S.A. Div. Jobin Yvon 91 165 Longjumeau France). Chapon P. Tournarie D. Statistical controls to improve the monitoring of charges in a steel plant. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Instrum. S.A. Div. Jobin Yvon 91165 Longjumeau France). Lee Y.-i. Song K. Cha H.-k. Lee J.-m. Park MA. Lee G.-h. Atmospheric effects and spatial differentiation on laser-ablated plasma emission by various laser systems. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept.Chem. Konyang Univ. Nonsan 320-800 South Korea). 3261 1-7200 USA). Journal of Analytical Atomic Spectrometry November 1996 Vol. 11 (443R-460R) 443R96/C4183 Stiop A. Hale R. The analysis of metals in lake sediments using microwave digestion a comparison of extractable and total digestion methods. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Water Resour. Inst. Grand Valley State Univ. Allendale MI 49401 USA). 96/C4184 Burelli F. Santoni F. Stroh A. Analysis of trace elements Be Al Cr Mn Fe Co Ni Cu Zn As Se Mo Ag Cd Sn Sb Ba Hg Pb in drinking waters by inductively coupled plasma mass spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Control and Res. Lab. in Hydrol. and Environment 20601 Bastia Corsica France).96/C4185 Wei L. Gupta P. Farhat F. Duboise S. Ultra trace analysis of selenium and arsenic at part per trillion N level by atomic fluorescence spectrometry with flow injection hydride generation technique. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Chem. Services Div. Bur. Lab. Texas Dept. Health Austin TX 87856-3199 USA). 96/C4186 Anderson K. A. Casey B. Diaz E. Markowski P. Speciation and determination of dissolved iodide and iodine in environmental aqueous samples by inductively coupled plasma atomic emission spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Food Sci. and Toxicol. Anal. Sci. Lab. Univ. Idaho Moscow ID 83844-2201 USA). 96/C4187 Coury L. A. Jr. Johnson M. Scanning tunneling microscopy in the analytical laboratory.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Duke Univ. Durham NC 27708 USA). 96/C4188 Xu K. Gusev A. Hercules D. M. Imaging of polymer surfaces by atomic force microscopy. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Pittsburgh Pittsburgh PA 15260 USA). 96/C4189 Eremenko A. M. Smirnova N. P. Spectroscopic indication of the surface properties of zeolites silica and alumina. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Inst. Surface Chem. Ukranian Acad. Sci. 252022 Kiev Ukraine). 96/C4190 Anzelmo J. A. Buman A. l. Yellepeddi R. Bonvin D. New combined XRF/XRD instrument for elemental and phase analysis for process and quality control in the production of aluminium metal.Pittsburgh Conference (PITTCON '961 Chicago IL USA March 3-8 1996 (ARL Dearborn MI 48120 USA). 96/C4191 Wagner E. P. 11 Smith B. W. Besteman D. A. Winefordner J. D. Ultratrace determination of lead in whole blood using electrothermal vaporization laser excited atomic fluorescence spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Florida Gainesville FL 96/C4192 Zhou E. Y. Zhu J. J. Richards M. P. Analysis of metallothioneins uia coupled capillary electrophoresis and inductively coupled plasma mass spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (CETAC Technologies Inc. Omaha NE 68107 USA). 96/C4193 Brenner I. B. Zander A Zhu J. Gutierrez A.Plantz M. Characterization of a membrane desolvation interface for trace element detection by solvent extrac- tion and ICP-MS. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Ginzton Res. Center Varian Associates Palo Alto CA 94305-1025 USA). 96/C4194 Neal P. J. Dymott T. C. Booth P. K. Real possibilities for PPT analysis in ICP-AES. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (AT1 Unicam Cambridge UK CB1 2PX). 3261 1-7200 USA). 96/C4195 Aldous K. M. Mills E. Slavin W. Qiao H. Parsons P. J. Evaluation of pulsed hollow cathode lamp background correction for a portable electrothermal atomic absorption spectrometer. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Wadsworth Center New York State Dept. Health Albany NY 12201-0509 USA).96/C4196 Yuzefovsky A. I. Lonardo R. F. Michel R. G. McCaffrey J. T. Extended calibration curves in Zeeman atomic absorption spectrometry. How far can we go? Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Res. Center Philip Morris USA Richmond VA 23234 USA). 96/C4 197 Carnrick G. Schlemmer G. Portala F. Feuerstein M. Method development considerations for multi- element graphite furnace AAS. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Perkin-Elmer Corp. Norwalk CT 06859 USA). 96/C4198 Schrader D. Webb C. Mika J. Vanclay E. Determining the optimum approach to processing transient signals in graphite furnace atomic absorption spectrometry (GFAAS). Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Varian Optical Spectroscopy Instruments Wood Dale IL 60191 USA). 96/C4199 Sutton R.L. Investigations into supplementary hydro- gen addition to a desolvated sample stream for the analyses of semiconductor grade gases by ICP-MS. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Electr. Dev. Fac. BOC Gases Research Triangle Park NC 27709-2338 USA). 96/C4200 Hunault P. Nelis R. Le Marchand A. Marcus R. K. Enhanced detector system for depth profile analysis by GD-RF. Full dynamic range on-the-fly. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Div. Jobin-Yvon Instruments S.A. 91165 Longjumeau France). 96/C4201 Miller-Ihli N. J. Fonseca R. W. Evaluation of different calibration strategies for ETV-ICP-MS. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (US Dept.Agric. Beltsville Human Nutr. Res. Center Beltsville MD 20705 USA). 96/C4202 Parker M. Hartenstein M. L. Marcus R. K. Depth- resolved analysis of solid materials utilizing the radiofre- quency glow discharge atomic emission source. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Howard L. Hunter Chem. Lab. Dept. Chem. Clemson Univ. Clemson SC 96/C4203 Kinzer J. A. Olesik J. W. Daniels L. B. Fundamental investigation of the origins of matrix effects in the ICP by observations of individual atom and ion clouds. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Lab. Plasma Spectrochem. Laser Spectrosc. Mass Spectrom. Dept. Geol. Sci. Ohio State Univ. Columbus OH 43210 USA).96/C4204 Clevenger W. K. Riter K. L. Mordoh L. S. Smith B. 29634-1905 USA). 96/C4205 96/C4206 444 R Journal of Analytical Atomic Spectrometry November 1996 Vol. 1 W. Winefordner J. D. Electrothermal vaporization with laser enhanced ionization detection in a flame an evaluation of the detection efficiency for magnesium. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Florida Gainesville FL 3261 1-7200 USA). Zhou J. X. Hou X. Yang K. X. Michel R. G. Tunable solid state laser applications in the laser excited atomic fluorescence spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Connecticut Storrs CT Kosman J. J. Advantages of the use of combined GC/MS/IR/AED for the analysis of unknowns.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (W. L. Gore and Associates Inc. Elkton MD 21922-1320 USA). 06269-3060 USA).96/C4207 96/C4208 96/C4209 96/C42 10 96/C42 1 1 96/C4212 96/C4213 96/C4214 96/C42 15 96/C42 16 96/C42 17 96/C42 18 Sullivan J. J. Quimby B. D. Dryden P. C. Cai X.-j. Johnson D. S. Improving GC-AEDs performance reliability ease of use operating cost computer control and size. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Hewlett-Packard Wilmington DE 19808 USA). Ramus T. L. Hein S. J. Automation of industrial applications for the GC-AED and elemental chromatog- rams. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Diablo Analytical Inc. Concord CA 94524 USA).Glass G. E. Schmidt K. W. Sorensen J. A. Rapp G. R. Jr. Measuring ecosystem metabolites from element loadings using headspace GC-AED techniques. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (USEPA Duluth MN 55804 USA). Olson N. L. Cummings R. Proposed EPA method 8085 utilizing GC-AED. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Manchester Environ. Lab. Washington State Dept. Ecol. Port Orchard WA 98366 USA). Brubaker K. L. O'Neill H. J. Rueda J. Schneider J. F. Zimmerman R. E. XRF measurements in a research and manufacturing facility. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Centre Environ. Restoration Systems Argonne Natl. Lab. Argonne IL 60439 USA). Schneider J. F. Hahn L. M. Lee J. K. Bohm A.Portable X-ray fluorescence for the determination of heavy metal contamination in soil on firing ianges. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Argonne Natl. Lab. Aryonne IL 60439 USA). Habibuddowia M. Studies on the determination of method detection limit (MDL) and its improl ement using ICP/USN. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Div. Eiiviron. Serv. NREPC Frankfort KY 40601 USA). Shrader D. Vanclay E. Determination of toxic elcments in toys using microsampling hydride generation itomic absorption spectrometry (HGAAS). Pithburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Varian Optical Spectroscopy Instruments Wood Dale IL 60191 USA). Sumiya K. Ashizawa T. Analysis of fine structure and properties of Bi2Sr2CaCu20x superconductor by ana- lytical TEM.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Ibaraki Re:. Lab. Hitachi Chemical Co. Ltd. Ibaraki 317 Japan). Kawabata K. Matsuda M. Kishi Y. Yamanaka K. Analysis of impurities in chemicals and materials for semiconductor by inductively coupled plasma mass spectrometry (ICP-MS). Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Res. & Dev. Yokogawa Anal. Systems Inc. 180 Tokyo Japan). Nicolussi G. K. Pellin M. J. Lykke K. R. 'Trevor J. L. Mencer D. E. Surface analysis by SNMS femtosecond laser postionization of sputtered and laser- desorbed atoms. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Mater. Sci. and Chem. Div. Argonne Natl. Lab.Argonne IL 60439 USA). Thomas A. E. Kolics A. Wieckowski A. Kortenaar M. T. Goeig J. Frens G. Formaldehyde adsorption on polycrystalline silver a radiotracer electrochemical and X-ray photoelectron spectroscopy approach. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Illinois Urbana IL 61801 USA). 96/C4219 96/C4220 96/C422 1 96/C4222 96/C4223 96/C4224 96/C4225 96/C4226 9 6/C 422 7 96/C4228 96/C4229 96/C4230 96/C423 1 Mermet J. M. Axial viewing of ICP emission history capabilities and potential. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Lab. Sci. Anal. Univ. Lyon F-69622 Villeurbanne France). Wilkinson W. R. Proctor A. Houalla M. Fiedor J. N. Hercules D. M. Characterization of supported MO catalysts by TOF-SIMS.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Univ. Pittsburgh Pittsburgh PA 15260 USA). Foster R. Crawford R. Axial viewing of ICP emission using PMT and imaging detector based spectrometers the role of optics. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Thermo Jarrell Ash Franklin MA 02038 USA). Ivaldi J. C. Carnrick G. Grosser Z. Can axial viewing of ICP emission replace GFAA? Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Perkin-Elmer Corp. Norwalk CT 06859 USA). Olesik J. W. Matrix effects and background in axial viewing of ICP emission. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Lab. Plasma Spectrochem. Laser Spectrosc. Mass Spectrom. Dept. Geol. Sci. Ohio State Univ.Columbus OH 43210 USA). Horlick G. Shao Y. Schroeder S. Chen G. Solid sample introduction and axial viewing of ICP emission. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Alberta Edmonton Alberta Canada T6G 2G2). Eanes R. C. Christopher S. J. Marcus R. K. Radiofrequency glow discharge ion trap mass spec- trometry using filtered noise fields elemental analysis and ion molecule chemistry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Clemson Univ. Clemson SC Burgoyne T. W. Hieftje G. M. Hites R. A. The design and characteristics of a plasma-source mass spectrograph. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. and Sch. Public and Environ. Affairs Indiana Univ.Bloomington IN 47405 USA). Zhang L. S. Combs S. M. Installed spray chamber as a gas-liquid separator for the determination of hydride elements by HG-ICP-MS. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Soil and Plant Anal. Lab. Univ. Wisconsin-Madison Madison WI 53705 USA) Huo D. Kingston H. M. Taylor D. B. Larget B. A new isotope dilution technique "speciated isotope dilution mass spectrometry" is described using Monte Carlo simulation. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. and Biochem. Duquesne Univ. Pittsburgh PA Pilon M. Belmore R. Mitchell P. Gulla R. Spark atomic emission analysis utilizing a high resolution echelle spectrometry with charge injection device detec- tion. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Thermo Jarrell Ash Franklin MA 02038 USA).Ray S. J. Mahoney P. P. Hieftje G. M. Evaluation of an atomic time-of-flight mass spectrometer for the analysis of microsamples and transient signals. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Indiana Univ. Bloomington IN 47405 USA). Liang D. C. A novel atomic fluorescence spectrometer for sub-PPB level elemental analysis. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Aurora Instruments Ltd. Vancouver British Columbia Canada V5Y 1K3). 29634-1905 USA). 15282-1503 USA). Journal of Analytical Atomic Spectrometry November 1996 Vol. 1 1 445 R96/C4232 Tzanani N. Jing H. Amirav A. The pulsed flame photometric detector-a universal heteroatom selective detector.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Sch. Chem. Tel Aviv Univ. Tel Aviv 69978 Israel). 96/C4233 La B. Qiu L. The study on interference of iron spectral lines to part of elements in ICP-AES analysis. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Nanjing Inst. Geol. and Min. Resour. Nanjing 210016 China). 96/C4234 Ferreira S. L. C. Spinola Costa A. C. Queiroz A. S. Use of 1-( 2-thiazolylazo)-p-cresol for preconcentration of nickel iron copper cobalt titanium vanadium and lead. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Inst. Quim. Univ. Fed. Bahia Bahia 40170-290 Brazil). 96/C4235 Conver T. Yang J. Koropchak J. Leighty D. Nafion membrane gas dryers for desolvation of organic sample streams with high performance sample introduction to ICP-AES. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept.Chem. and Biochem. Southern Illinois Univ. Carbondale IL 96/C4236 Sadain S. K. Szostek B. Koropchak J. A. Fundamental investigations of the effects of aerosol flow on discrete sample introduction. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. and Biochem. Southern Illinois Univ. Carbondale IL 62901-4409 USA). 96/C4237 Tatsy Y. G. Stakheev Y. I. Comparison characteristics of collectors for mercury determination. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Vernadsky Inst. Geochem. and Anal. Chem. 117334 Moscow Russia). 96/C4238 Liu H. Koropchak J.A. Noise diagnosis and control for thermospray sample introduction systems with 40 MHz ICP-AES. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Southern Illinois Univ. Carbondale IL 62901-4409 USA). 96/C4239 Baker C. L. Smith B. W. Winefordner J. D. Bolshov M. A. The determination of mercury in silver by laser excited atomic fluorescence spectrometry with electro- thermal atomization. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Florida Gainesville FL 3261 1 USA). 96/C4240 Handy R. W. Fernando R. A. Lang M. McNeill G. Goldberg M. M. Determination of selenium in biologi- cal samples. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Res. Triangle Inst. (RTI) Research Triangle Pk.NC 27709 USA). 96/C4241 Bezsudnov I. V. Sevryukov V. A. Tatsy Y. G. Identification of multicomponent alloys by ETA-AAS. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Sci. and Prod. Enterprise "Nauka-Service" 103473 Moscow Russia). 96/C4242 Kubrakova I. ETAAS determination of noble metals in geological samples with a high content of organic matter. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Vernadsky Inst. Geochem. and Anal. Chem. Russian Acad. Sci. Moscow 117975 Russia). 96/C4243 Shrader D. Flajnik-Rivera C. The determination of major elements in antacids and vitamins by flame AA using an integrated sample introduction system for solution preparation. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Varian Optical Spectroscopy Instruments Wood Dale IL 60191 USA).96/C4244 Conver T. S. Koropchak J. A. Fundamental studies of high flow fused silica aperture based thermospray. Pittsburgh Conference (PITTCON '96) Chicago IL 6290 1-4409 USA). USA March 3-8 1996 (Dept. Chem. and Biochem. Southern Illinois Univ. Carbondale IL 62901-4409 USA). 96/C4245 Boparai A. S. Henning T. Tsai Y. Smith L. L. Coleman E. L. Cleanup of radioactive mixed waste sample extracts. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Anal. Chem. Lab. Chem. Tech. Div. Argonne Natl. Lab. Argonne IL 60439 USA). 96/C4246 Thompson L. J. Trace metal determinations in environ- mental samples using an ICP-AES system equipped with an ultrasonic nebulizer. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Research Triangle Inst.Research Triangle Pk. NC 27709 USA). 96/C4247 Yaeger J. S. Smith L. L. Application of high-pressure microwave digestion to radiochemical analyses. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Anal. Chem. Lab. Chem. Technol. Div. Argonne Natl. Lab. Argonne IL 96/C4248 Karmarkar S. V. Rapid ion chromatographic determi- nation of sulfate in water and soil extracts. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Lachat Instruments Inc. Milwaukee WI 53218 USA). 96/C4249 Pegg R. K. Saunders M. S. DNA analysis by LIF videomicrography. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Nucleic Assays Corp. Amelia Island FL 32034 USA). 96/C4250 Guan H.M. Kingston H. M. On-line sample prep- aration and selective preconcentration of transition metals from high concentrations of matrix elements. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. and Biochem. Duquesne Univ. Pittsburgh PA 15282-1503 USA). 96/C4251 Reed N. M. Mennie D. PlasmaTrace 2 high resolution ICP-MS with enhanced mistral detection limits. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Fisons Instruments Elemental Analysis Winsford UK CW7 6XB). 96/C4252 de Carvalho M. S. Massena Ferreira E. M. Mantovano J. L. Sorvent extraction preconcentration and direct determination of lead by X-ray fluorescence. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Inst. Engenharia Nucl.Brazil). 96/C4253 Moseley Z. Dulude J. Some applications of atomic absorption spectroscopy in the food industry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Thermo Jarrell Ash Franklin MA 02038 USA). 96/C4254 Fang Y. Hydrogen peroxide as oxidant agent for the determination of trace lead in food samples by HG-AAS. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8,1996 (Fuzhou Health and Quarantine Bur. Fuzhou Fujian 350001 China). 96/C4255 Indurthy S. Sneddon J. Smith M. Lee Y. I. Deval A. Direct and near real-time determination of metals in air by impaction-graphite furnace atomic absorption spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. McNeese State Univ. Lake Charles LA 70609 USA).96/C4256 Raith A. Sigsworth P. T. Henry R. Environmental monitoring using laser ablation ICP-MS. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Fisons Instruments Elemental Analysis Winsford Cheshire UK CW7 3BX). 96/C4257 Geiger W. M. Meyer C. J. The analysis of PPB metal hydride impurities in specialty gases by GC/RGD. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Merlin Microscience Ind. Houston TX 77224 USA). 60439-4831 USA). 446 R Journal of Analytical Atomic Spectrometry November 1996 Vol. 1 196/C4258 96/C4259 9 6/C42 60 96/C4261 96/C4262 96/C4263 96/C4264 96/C4265 96/C4266 96/C4267 96/C4268 96/C4269 96/C4270 Lu Q. Barnes R. M. Separation and quantification of metallothioneins by capillary electrophoresis and induc- tively coupled plasma mass spectrometry.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Lederle Grad. Res. Tower Univ. Massachusetts Amherst MA 01003-4510 USA). Harper D. L. Adair J. Jedrejcic D. Riley J. T. Depth profile and bulk analyses using a dual s,iurce glow discharge atomic emission spectroineter. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Phys. and Astrorl. and Mater. Characterization Center Western Kentucky Univ. Bowling Green KY 42101 USA). Pan X. Harville T. R. Marcus R. K. Analysis of simulated nuclear waste by glow discharge atomic emission spectrometry. Pittsburgh Confvrence (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Clemson Univ. Clemson SC Zhu J. J. Gutierrez A. Determination of boron in steel by laser ablation and inductively coupled plasma mass spectrometry.Pittsburgh Conference (PIT2 CON '96) Chicago IL USA March 3-8 1996 (CETAC Technologies Inc. Omaha NE 68107 USA). Munoz T. Jr. Schleisman A. J. The role of mclisture in ETV-ICP-MS. Pittsburgh Conference (PIT? CON '96) Chicago IL USA March 3-8 1996 (Texas Instruments Dallas TX 75265 USA). Hodges C. Kamenschikov A. Meyer G. Autclmatic polarity switching DC-ARC a tool to augment inulti- element analysis of solids. Pittsburgh Confcrence (PITTCON '96) Chicago IL USA March 3-8 1996 (Thermo Jarrell Ash Franklin MA 02038 USA) Brenner I. B. Zander A. Henderson A. Direct solids analysis of geological and related materials-a cornpari- son of spark ablation and slurry nebulization ICP- AES.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Ginzton Res. Centre Varian Associates Palo Alto CA 94305-1025 USA). 29634-1905 USA). Horner J. A. Hieftje G. M. Computer simulation of the vaporization of mixed solute particles in an ICP. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Indiana Univ. Bloomington IN 47405 USA). Amad M. Houk R. S. Effect of a secondary discharge on optical emission from a Mach disk extracted from an ICP. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Ames Lab. US Dept. Energy Dept. Chem. Iowa State Univ. Ames IA 50011 USA). Sesi N. N. Hieftje G. M. Fundamental studies on interelement matrix effects in the ICP. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Chem.Dept. Indiana Univ. Bloomi ngton IN 47405 USA). Lehn S. A. Hieftje G. M. A possible linear relationship in ICP matrix effects. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Indiana Univ. Bloomington IN 47405 USA). Van der Hoeff A. A. Krupa R. Hu K. Luan S. Advances made in plasma optical emission mass spectroscopy (POEMS). Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Thermo Jarrell Ash Franklin MA 02038 USA). Pilon M. Dynamic range enhancements on charge injection device based atomic emission systems. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Thermo Jarrell Ash Frmklin MA 02038 USA). 96/C4271 96/C4272 96/C4273 96/C4274 96/C4275 96,424276 96/C4277 9 6/C 42 7 8 96/C4279 96/C4280 96/C428 1 96/C4282 96/C4283 Brickhouse M.Rodriguez A. Gonzalez E. Williams B. Stuff J. Hoffland L. The use of GC/AED GC/IRD and GC/MS for the characterization of trace level chemicals relevant to the chemical weapons convention (CWC). Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (EAI Corp. Abingdon MD 21009 USA). Hardas N. R. Adam R. Uden P. C. Selective determination of gasoline olefins by gas chromatogra- phy coupled to atomic emission detection (GC-AED). Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Massachusetts Amherst MA 01003-4510 USA). Scott B. F. Parrott J. L. Sherry J. P. Comba M. E. Analysis of fractionated refinery effluents by GC/AED and GC/MS. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8,1996 (Aquatic Ecosystem Conservation Branch Natl.Water Res. Inst. Burlington Ontario Canada L7R 4A6). Chau Y.K. Yang F. Brown M. Determination of methylcyclopentadienyl manganese tricarbonyl (MMT) and alkyllead compounds by gas chromatography- atomic emission detection (GC-AED)-MMT and alkyl- lead residues in environmental samples. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Natl. Water Res. Inst. Environ. Canada Burlington Ontario Canada L7R 4A6). Hedrick J. Bakowska E. The analysis of soil and sludge digests for trace metals by ICP-MS. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Hewlett-Packard Co. Wilmington DE 19808 USA). Taylor D. Nogay D. Huo D. Kingston H. M. On- line chromatographic ICP-MS analysis of traditionally difficult environmental samples.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. and Biochem. Duquesne Univ. Pittsburgh PA 15282-1503 USA). Meyer G. A. Foster R. Carroll C. Toothaker T. ICP-AES for process monitoring an instrument choice worth considering. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Thermo Jarrell Ash Franklin MA 02038 USA). Denton M. B. Atomic and molecular spectroscopy with array detectors. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Arizona Tucson AZ 85721 USA). Shrader D. Determination of mercury at the ppt level. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Varian Optical Spectroscopy Instruments Wood Dale IL 60191 USA).Deraed C. Samuel 0. A rapid elemental determination (including traces) of environmental samples with an ICP-AES. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Instruments S.A. Division Jobin Yvon 91 165 Longjumeau France). Belmore R. Pilon M. Mitchell P. Gulla R. Steel analysis by spark emission utilizing a high resolution CID based echelle spectrometer. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Thermo Jarrell Ash Franklin MA 02038 USA). Smith M. V. Sneddon J. Indurthy S. Lee Y. I. Deval A. Determination of chromium lead and mercury in cigarette smoke by impaction-graphite furnace atomic absorption spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept.Chem. McNeese State Univ. Lake Charles LA 70609 USA). Stux R. Foster R. Bulman F. Strategies for analysis of organic solvents in the axial ICP. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Thermo Jarrell Ash Franklin MA 02038 USA). Journal of Analvtical Atomic Svectrometrv November 1996 Vol. 11 447 R96/C4284 96/C428 5 96/C4286 96/C4287 96/C4288 96/C42 89 9 6/C42 90 96/C429 1 9 6/C429 2 96/C4293 96/C4294 96/C4295 Shkolnik J. Brenner I. Zander A. Kim S. Overcoming solvent overloading in the ICP by emulsi- fication determination of Pb in gasoline and other volatile solvents. Pittsburgh Conference ( PITTCON '96) Chicago IL USA March 3-8 1996 (Varian Optical Spectroscopy Instruments Wood Dale IL 60191 USA). Zhu J. J. Brenner I. B. Geolaser probe-a versatile laser ablation system for the direct analysis of geological materials by ICP-AES and MS.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (CETAC Technologies Inc. Omaha NE 68107 USA). Sigsworth P. T. Godfrey J. Koller D. Brown P. Automated analysis of biological samples by ICP-MS. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Fisons Instruments Elemental Analysis Winsford Cheshire UK CW7 38X). Kogan V. V. Quality control of pure silver by laser ablation ICP mass spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Royal Canadian Mint Ottawa Canada K1A OG8). Thaxton K. Olesik J. W. Olesik S. V. Electrospray and ionspray mass spectrometry for elemental speci- ation. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Lab.Plasma Spectrochem. Laser Spectrosc. Mass Spectrom. Dept. Geol. Sci. Ohio State Univ. Columbus OH 43210 USA). Stockwell P. B. Corns W. T. Perkins R. Jones R. A new fully automatic gas chromatography system designed specifically for mercury speciation. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (PS Analytical Ltd. Orpington Kent UK BR5 3HP). Fischer R. G. Rapsomanikis S. Andreae M. 0. Direct determination of methylmercury in sea-water using sodium tetraethylborate derivatization followed by GC separation and AA detection. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Biogeochem. Dept. Max Planck Inst. Chem. 55020 Mainz Germany). Stockwell P. B. Corns W. T. Preconcentration atomic fluorescence-a fully automated system to extend the range of analysis for mercury from to gms/litre.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (PS Analytical Ltd. Orpington Kent UK BR5 3HP). Pfeil D. Ballantyne K. Dealing with the changing requirements of continuous flow mercury analysis by cold vapour atomic absorption. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Thermo Jarrell Ash Franklin MA 02038 USA). Mermet J. M. Robustness and precision in ICP-atomic emission spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Lab. Sci. Anal. Univ. Lyon F-69622 Villeurbanne France). Horlick G. Simplicity and capability in sources and detectors. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept.Chem. Univ. Alberta Alberta Canada T6G 2G2). Winefordner J. D. Toward standardless analysis and the ultimate detection limit. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Florida Gainesville FL 3261 1 USA). 96/C4297 Ellis R. Sundin N. G. Ge H. Tyson J. Hanna C. P. McIntosh S. Determination of selenium species by flow injection hydride generation electrothermal atomiz- ation AAS and plasma source mass spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Massachusetts Amherst MA 01003-4510 USA). 96/C4298 Teague S. M. Wang HA. Davis M. K. Speciation and low level detection of arsenic in water by cold trapping/hydride generation atomic absorption spec- troscopy. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Metropolitan Water District of Southern California La Verne CA 91750 USA).96/C4299 Bass D. A. Yaeger J. S. Kiely J. T. Crain J. S. Gowdy M. J. Shem L. M. O'Neill H. J. Mohrman G. B. Besmer M. High-performance liquid chromatog- raphy inductively coupled plasma mass spectrometry (HPLC-ICP-MS) for measurement of arsenic species in environmental samples. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Anal. Chem. Lab. Chem. Technol. Div. Argonne Natl. Lab. Argonne IL 60439 USA). 96/C4300 Yoshizawa D. Yamamoto S. Ishiwata K. Takamatsu T. Determination of S- and P-containing anionic surfactants in cleansing cosmetics by high-performance liquid chromatography with inductively coupled plasma atomic emission spectrometric detection.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Anal. Res. Group Safety and Anal. Res. Centre Res. and Dev. Headquarters Shiseido Co. Ltd. Yokohama 223 Japan). 96/C4301 Wu G. J. C. Lee C. C. Determination and speciation of manganese in sea-water. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Natl. Taiwan Normal Univ. Taipei 11718 Taiwan China). 96/C4302 Boughriet A. Deram L. Wartel M. Evolution of the [Cr(rII) djss.[Cr(vI) diss. ratio under the influence of a colloidal source generated by industrial wastes in the southern region of the North Sea. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Lab. Chim. Anal. et Marine Univ. Lille 59655 Villeneuve d'Ascq France).96/C4303 Shrader D. Moffett J. Vanclay E. Single standard calibration and on-line over range sample dilution in hydride generation atomic absorption spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Varian Optical Spectroscopy Instruments Wood Dale IL 60191 USA). 96/C4304 Becotte-Haigh P. Tyson J. F. Denoyer E. McIntosh S. Flow injection techniques for interference removal in plasma source mass spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Massachusetts Amherst 96/C4305 Shrader D. Vanclay E. Simplifying standard additions analyses in flame atomic absorption (FAAS) using an innovative pump based diluter. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 ( Varian Optical Spectroscopy Instruments Wood Dale IL 60191 USA).96/C4306 Hanna C. P. Baasner J. Leyrer M. Sperling M. Fang Z. Extension of analytical working ranges in atomic spectroscopy with on-line dilution. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Inorg. Anal. Div. Perkin-Elmer Corp. Norwalk CT 06097-0215 USA). 96/C4307 Wojciechowski M. Naser N. Harpold M. Wegner S. Henkens R. O'Dals J. A fast and simDle method MA 01003-4510 USA). 96/C4296 Hieftje G. M. High-precision interference-free atomic for direct determination of lead in whole blood using mass spectrometry. Pittsburgh Conference (PITTCON colloidal gold modified disposable sensors and a single- '96) Chicago IL USA March 3-8 1996 (Dept. Chem. key electrochemical monitor.Pittsburgh Conference Indiana Univ. Bloomington IN 47405 USA). (PITTCON '96) Chicago IL USA March 3-8 1996 Journal of Analytical Atomic Spectrometry November 1996 Vol. 1 1 448R96/C4308 96/C4309 96/C43 10 96/C4311 96/C43 12 96/C43 13 96/C43 14 96/C43 15 96/C43 16 96/C43 17 96/C4318 96/C43 19 (ANDCARE Inc. Research Triangle Pk. NC 27709 USA). Roberts R. Q. Automated sample preparation and thin layer chromatographic (TLC) analysis of acid base and neutral drugs and their metabolites in multiple urine samples. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (ANSYS Inc. Irvine CA 92718 USA). Brockman P. J. Drislane W. F. A simple lop cost electrothermal atomic absorption spectrometer for the determination of lead in blood. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8.1996 (Exeter Analytical Inc. N. Chelmsford MA 01863 USA). Bakowska E. Lord R. S. The room-temperature digestion of blood samples for analysis by ICP-MS. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Hewlett-Packard Co. Wilmington DE 19808 USA). Wang L. Jarrett J. M. Browner R. E. Evaluation of current microflow nebulizers for inductively coupled plasma mass spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Sch. Chem. and Biochem. Georgia Inst. Technol Atlanta GA 30332-0400 USA). Riley J. T. Riley J. M. Cao Q. Harper D. L. idair J. Jedrejcic D. Calibration of a glow discharge atomic emission spectrometer for quantitative depth profile and bulk analyses. Pittsburgh Conference (PIT? CON '96) Chicago IL USA March 3-8 1996 (Dept.Chem. and Mater. Characterization Center Western Ker tucky Univ. Bowling Green KY 42101 USA). Fitzgerald N. Tyson J. F. Jassie L. B. Improved transport efficiency and drying of the aerosol for plasma spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Massachusetts Amherst MA 01003-4510 USA). Minnich M. G. Houk R. S. Woodin M. A. Cryogenic desolvation and ICP-MS application sl udies. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Ames Lab. US Dept. Energy Dept. Chem. Iowa State Univ. Ames IA 50011 USA). Pack B. W. Ray S. J. Hieftje G. M. A new rapidly clearing spray chamber for ultrasonic nebulization in inductively coupled plasma spectrometry.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Indiana Univ. Bloomington IN 47405 USA). Allen L. A. Leach J. J. Pang H.-m. Houk R. S. Use of a monodisperse droplet generator with a twin quadrupole inductively coupled plasma mass spec- trometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Ames Lal,. US Dept. Energy Dept. Chem. Iowa State Univ. ,4mes IA 50011 USA). Gluodenis T. J. Jr. Thomas R. Debrah E. Beres S. Denoyer E. Jacksier T. Advanced ICP-MS sample introduction techniques including the use of cold plasma conditions for the analysis of critical sernicon- ductor elements. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Inorg. Anal. Prod. Dept. Perkin-Elmer Corp. Wilton CT 06897 USA).Jimenez M. S. Laborda F. Mir J. M. Castillo J. R. Flow injection electrochemical hydride generator for atomic spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Anal. Spectrosc. and Sensors Group Dept. Anal. Chem. Fac. Sci. Univ. Zaragoza 50009 Zaragoza Spain). Eastgate A. Electrical modification of ICP sample carry-over effects. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Varian Australia Pty Ltd. Clayton Victoria 3 169 Australia). 96/C43 20 96/C43 2 1 96/C4322 96/C4323 96/C4324 96/C4325 96/C43 26 96/C4327 96/C4328 96/C4329 96/C4330 96/C433 1 Eastgate A. The pitter-patter of little droplets-the temporal significance of nebulizer self-charging. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Varian Australia Pty Ltd.Clayton Victoria 3169 Australia). Erickson M. D. Aldstadt J. H. Alvarado J. S. Crain J. S. Orlandini K. A. Smith L. L. Analytical methods for environmental radionuclides. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Environ. Res. Div. and Chem. Technol. Div. Argonne Natl. Lab. Argonne IL 60439-4837 USA). Conver T. S. Koropchak J. A. Shkolnik G. Flajnik- Rivera C. Optimization and characterization of fused silica aperture thermospray with an axial viewed ICP- AES. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. and Biochem. Southern Illinois Univ. Carbondale IL 62901-4409 USA). Lewis L. C. Henscheid J. P. Hand R. L. Chemical analysis of high level mixed waste samples. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8,1996 (Lockheed Martin Idaho Technologies Idaho Natl.Eng. Lab. Idaho Falls ID 83403 USA). Griest W. H. Wolfe P. F. Harmon S. H. Maskarinec M. P. Schenley R. L. Worthy L. T. Weaver J. H. Analysis of transuranic wastes for regulatory organics. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Chem. and Anal. Sci. Div. Oak Ridge Natl. Lab. Oak Ridge TN 37831-6120 USA). Diamond D. A universal method for reduction of reagent consumption in USEPA compliance monitoring methods using flow injection analysis. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Lachat Instruments Milwaukee WI 53218 USA). Morton J. S. Newberry W. R. A mixed analyte performance evaluation program operated by the United States Department of Energy.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Radiol. and Environ. Sci. Lab. US Dept. Energy Idaho Falls ID 83401 USA). Fernando R. Goldberg M. Pellizzari E. D. Sheldon L. S. Lang M. Determination of arsenic in food biological and environmental samples at ultra-trace levels using vapour generation atomic fluorescence spectrometry. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Res. Triangle Inst. Research Triangle Park NC 27709 USA). Su W. Harwood J. J. Simultaneous analysis of selenium species by ion chromatography with atomic spectroscopic detection. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Tennessee Technol. Univ. Cookeville TN 38501 USA).Fumal E. Routine determination of lead in sea water by GF-AA. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Coastal Environ. Lab. Univ. Connecticut Avery Point Groton CT Oms M. T. Cerda V. Cerda A. Application of multicomponent analysis and sequential injection analy- sis for the rapid determination of total nitrogen. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Balearic Islands 07071 Palma de Mallorca Spain). Houk R. S. Allen L.A. Leach J. J. Pang H.-m. Minnich M. M. Wang J. Recent progress in sample introduction for atomic spectroscopy. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Ames Lab. Dept. Chem. Iowa State Univ. Iowa IA 50011 USA). 06340-6097 USA). Journal of Analytical Atomic Spectrometry November 1996 Vol.11 449R96/C43 32 961C4333 96/C43 34 96/C433 5 961C4336 96/C43 3 7 9614338 96/43 39 9 614 340 9614341 9614342 9614343 9614344 450R Browner R. F. Wang L. Ho S. Shou W. How many nebulizers do you need for ICP and ICP-MS? Is the answer still blowing in the wind? Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Sch. Chem. and Biochem. Georgia Inst. Technol. Atlanta GA 30332-0400 USA). Berndt H. Hydraulic high-pressure nebulization (HHPN) and high temperature HHPN (HT HHPN) on-line sample pretreatment and high-performance nebulization systems. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Inst. Spektrochem. Angew. Spektrosk. D-44139 Dortmund Germany). Jong R. From an ink-jet to a nebulizer the story of the monodisperse dried microparticulate injector.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Inst. Aerospace Studies Univ. Toronto Downsview Ontario Canada M3H 5T6). Smith T. Design and performance of a CCD array spectrometer with an argon flushed spark source for metals analysis. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Arun Technology Ltd. Southwater W. Sussex UK RH13 7UD). Lam K. K. K. Chan W. T. A new laser sampling technique for the inductively coupled plasma-atomic emission spectroscopy. Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Dept. Chem. Univ. Hong Kong Hong Kong). Wentworth W. E. Helias N. Chen E. C. M. Swatloski R. Stearns S. D. Pulsed discharge photoionization detector (PDPID) response of various classes of compounds in the Ar or Kr doped PDPID.Pittsburgh Conference (PITTCON '96) Chicago IL USA March 3-8 1996 (Univ. Houston TX 77204-5641 USA). Ahsanullah M. Ying W. Toxic effects of dissolved copper on Penaeus merguiensis and Penaeus monodon. Bull. Enuiron. Contam. Toxicol. 1995,55 81. (Australian Nuclear Sci. and Technol. Org. Menai NSW 2234 Australia). Otte M. L. Kearns C. C. Doyle K. M. 0. Accumulation of arsenic and zinc in the rhizosphere of wetland plants. Bull. Enuiron. Contam. Toxicol. 1995 55 154. (Dept. Botany Univ. Coll. Dublin Dublin 4 Ireland). Richards V. L. Beitinger T. L. Reciprocal influences of temperature and copper on survival of fathead minnows Pimephales promelas. Bull. Environ. Contam. Toxicol.1995 55 230. (Dept. Biol. Sci. Univ. North Texas Denton TX 76203 USA). Tataruch F. Red deer antlers as biomonitors for lead contamination. Bull. Environ. Contam. Toxicol. 1995 55 332. (Inst. Wildlife Res. and Ecol. Vet. Univ. Vienna 1160 Wien Austria). Al-Saleh I. Coate L. Paint as another possible source of lead exposure in Saudi Arabia. Bull. Environ. Contam. Toxicol. 1995 55 347. (Biol. and Med. Res. Dept. King Faisal Specialist Hospital and Res. Centre Riyadh 1121 1 Saudi Arabia). Matthews S. L. McCracken I. R. Lonergan G. Mercury contamination of gold courses due to pesticide use. Bull. Environ. Contam. Toxicol. 1995 55 390. (Environ. Protection Branch Environ. Canada Dartmouth NS Canada B2Y 2N6). Fitzner R. E. Gray R. H. Hinds W. T. Heavy metal concentrations in great blue heron fecal castings in Washington State a technique for monitoring regional and global trends in environmental contaminants.Bull. Enuiron. Contam. Toxicol. 1995 55 398. (Battelle Pacific Northwest Lab. Richland WA 99352 USA). 9614345 9614346 9614347 9614348 9614349 9614350 9614351 9614352 9614353 9614354 9614355 9614356 9614357 Journal of Analytical Atomic Spectrometry November 1996 Vol. 11 Bilski J. J. Aha A. K. Transport of heavy metals and cations in a fly ash amended soil. Bull. Environ. Contam. Toxicol. 1995 55 502. (IFAS Citrus Res. and Education Center Univ. Florida Lake Alfred FL 33850 USA). Bischof C. Heavy metal concentrations of the endopara- sitoid Glyptapanteles liparidis bouche (Hymenoptera) in contaminated Lymantria dispar L.larvae (Lepidoptera). Bull. Environ. Contam. Toxicol. 1995 55 533. (Dept. Ecophysiol. Inst. Zoology Univ. Vienna 1090 Vienna Austria). Khan A. T. Diffay B. C. Datiri B. C. Forester D. M. Thompson S. J. Mielke H. W. Heavy metals in livers and kidneys of goats in Alabama. Bull. Environ. Contaw. Toxicol. 1995 55 568. (School Vet. Med. Tuskegee Univ. Tuskegee AL 36088 USA). Al-Ghais S. M. Heavy metal concentrations in the tissue of Sparus sarba Forskal 1775 from the United Arab Emirates. Bull. Enuiron. Contam. Toxicol. 1995 55 581. (Desert and Marine Environ. Res. Center United Arab Emirates Univ. Al-Ain United Arab Emirates). Sakamoto M. Nakano A. Comparison of mercury accumulation among the brain liver kidney and the brain regions of rats administered methylmercury in various phases of postnatal development.Bull. Enuiron. Contam. Toxicol. 1995 55 588. (Dept. Epidemiol. Natl. Inst. Minamata Disease Kumamoto 867 Japan). Tahvonen R. Kumpulainen J. Lead and cadmium contents in milk cheese and eggs on the Finnish market. Food Addit. Contam. 1995 12( 6) 789. (Lab. Food Chem. Food Res. Inst. Agric. Res. Centre Finland 3 1600 Jokioinen Finland). Testolin G. Erba D. Ciappellano S. Bermano G. Influence of organic acids on aluminium absorption and storage in rat tissues. Food Addit. Contam. 1996 13( l) 21. (Dept. Food Sci. and Technol. Univ. Milan 20133 Milan Italy). Urieta I. Jalon M. Eguileor I. Food surveillance in the Basque Country (Spain). 11. Estimation of the dietary intake of organochlorine pesticides heavy metals arsenic aflatoxin MI iron and zinc through the Total Diet Study 1990191.Food Addit. Contam. 1996 13( l) 29. (Dept. Sanidad Direccion Salud Publica 0 1006 Vitoria-Gas teiz Spain). Mueller M. Anke M. Hartmann E. Illing-Guenther H. Oral cadmium exposure of adults in Germany. 1 Cadmium content of foodstuffs and beverages. Food Addit. Contam. 1996 13( 3) 359. (Bio1.-Pharm. Fac. Inst. Nutrition and Environ. Freidrich Schiller Univ. Jena 07743 Jena Germany). Capar S. G. Yess N. J. US Food and Drug Administration survey of cadmium lead and other elements in clams and oysters. Food Addit. Contam. 1996 13(5) 553. (Center Food Safety and Applied Nutrition Food and Drug Administration Washington DC 20204 USA). Lowe N. M. Hall E. J. Anderson R. S. Batt R. M. Jackson M. J. A stable isotope study of zinc kinetics in Irish setters with gluten-sensitive enteropathy. Br.J . Nutr. 1995 74 69. (Dept. Med. Univ. Liverpool Liverpool UK L69 3BX). Al-Masri M. R. Absorption and endogenous excretion of phosphorus in growing broiler chicks as influenced by calcium and phosphorus ratios in feed. Br. J . Nutr. 1995 74 407. (Dept. Radiation Agriculture Atomic Energy Commission Damascus Syria). Wright A. J. A. Southon S. Bailey A. L. Finglas P. M. Maisey S. Fulcher R. A. Nutrient intake and biochemical status of non-institutionalized elderly sub- jects in Norwich comparison with younger adults and adolescents from the same general community. Br. J. Nutr. 1995 74 453. (Inst. Food Res. Norwich Lab. Colney Norwich UK NR4 7UA).9614358 9614359 9614360 9614361 9614362 9 614 3 6 3 9614364 9614365 96/43 66 9 614 3 6 7 9614368 9614369 9614370 Gueux E.Azais-Braesco V. Bussiere L. Grolier P. Mazur A Rayssiguier Y. Effect of magnesium deficiency on triacylglycerol-rich lipoprotein and tissue susceptibility to peroxidation in relation to vitamin E content. Br. J. Nutr. 1995 74 849. (Centre Recrierche Nutrition Humaine Lab. Maladies Metabol. i NRA 63 122 St-Genes-Champanelle France). Tong K. K. Hannigan B. M. McKerr G. Strain J. J. The effects of copper deficiency on human lymphoid and myeloid cells an in vitro model. Br. J. Nutr. 1996 75 97. (Cancer and Ageing Res. Group Univ. Ulster Coleraine UK BT52 1SA). Wienk K. J. H. Marx J. J. M. Lemmens 4. G. Brink E. J. Van Der Meer R. Beynen A. C. Mechanism underlying the inhibitory effect of high calcium carbonate intake on iron bioavailabilit q from ferrous sulphate in anaemic rats.Br. J. Nutr. 1996 75 109. (Dept. Lab. Animal Sci. Utrecht Univ. 3508 TD Utrecht Netherlands). Davidsson L. Mackenzie J. Kastenmayer P. Aggett P. J. Hurrell R. F. Zinc and calcium apparent absorption from an infant cereal a stable isotope study in healthy infants. Br. J. Nutr. 1996 75 291. (Nestle Res. Center Nestec Ltd 1000 Lausanne Switzei land). Younes H. Demigne C. Remesy C. Acidic fermen- tation in the caecum increases absorption of calcium and magnesium in the large intestine of the rat. Br. J. Nutr. 1996 75 301. (Lab. Maladies Metabol. INRA Clermont-FerrandIThiex 63 122 Saint-Genes- Champanelle France). Davidsson L. Almgren A. Sandstroem B. Juillerat M.-A.Hurrell R. F. Zinc absorption in adult hJmans the effect of protein sources added to liquid test meals. Br. J. Nutr. 1996 75 607. (Nestle Res. Centre Nestec Ltd. 1000 Lausanne 26 Switzerland). Van Dokkum W. De La Gueronniere V. Schaafsma G. Bouley C. Luten J. Latge C. Bioavailability of calcium of fresh cheeses enteral food and inineral water. A study with stable calcium isotopes in young adult women. Br. J. Nutr. 1996 75 893. (TNO Nutrition and Food Res. Inst. 3700 AJ Zeist Netherlands). Hieftje G. M. The future of plasma spectrocliemical instrumentation. J. Anal. At. Spectrom. 1996 11 613. (Dept. Chem. Indiana Univ. Bloomington IN 47405 USA). Schram D. C. Van Der Mullen J. A. M. De Regt J. M. Benoy D. A. Fey F. H. A. G. De Grootte F. Jonkers J. Fundamental description of spectrocliemical inductively coupled plasmas.J. Anal. At. Spectrom. 1996 11 623. (Dept. Phys. Eindhoven Univ. Technol. 5600 MB Eindhoven Netherlands). Byrdy Brown F. Olson L. K. Caruso J. A. Comparison of electrospray and inductively coupled plasma sources for elemental analysis with mass spectrometric detec- tion. J. Anal. At. Spectrorn. 1996,11,633. (Dept. Chem. Univ. Cincinnati Cincinnati OH 45221-0172 I JSA). Becker J. S. Seifert G. Saprykin A. I. Dietze H.-J. Mass spectrometric and theoretical investigaticm into the formation of argon molecular ions in plasma mass spectrometry. J . Anal. At. Spectrom. 1996 11 643. (Zentralabteilung Chem. Anal. Forschungsi.entrum Juelich GmbH 52425 Dresden Germany). Treshchalov A. B. Chizhik A. S. Vill A. A. Spectrochemical analysis of trace contaminmts in helium (helium-fluorine) pulsed discharge plasmas.J. Anal. At. Spectrom. 1996 11 649. (Inst. Phis. 2400 Tartu Estonia). Westheide J. Th. Becker J. S. Jager R. Dietze H.-J. Broekaert J. A. C. Analysis of ceramic layers for solid oxide fuel cells by laser ablation inductively 2oupled plasma mass spectroscopy. J. Anal. At. Spectrorri. 1996 11 661. (Zentralabteilung Chem. Anal. 9614371 9 614 3 7 2 9614373 9614374 9614375 96/43 76 96/43 77 96/43 7 8 9614379 9 6/43 80 961438 1 9614382 Forschungszentrum Julich GmbH 52425 Julich Germany). Ghazi A. M. McCandless T. E. Vanko D. A. Ruiz J. New quantitative approach in trace elemental analysis of single fluid inclusions applications of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS).J. Anal. At. Spectrom. 1996 11 667. (Dept. Geol. Georgia State Univ. Atlanta GA 30303 USA). Botto R. I. Zhu J. J. Universal calibration for analysis of organic solutions by inductively coupled plasma atomic emission spectrometry. J. Anal. At. Spectrorn. 1996 11 675. (Baytown Chem. Plant Lab. Exxon Chem. Co. Baytown TX 77522-4004 USA). Li J. Improving analytical precision by utilizing intrinsic internal standards for determining minor constituents by inductively coupled plasma atomic emission spectrometry. J . Anal. At. Spectrom. 1996 11 683. (Tech. Assistance Lab. Osram Sylvania Inc. Beverly MA 01915 USA). Winefordner J. D. Wagner E. P. II. Smith B. W. Status of and perspectives on microwave and glow discharges for spectrochemical analysis.J. Anal. At. Spectrom. 1996 11 689. (Dept. Chem. Univ. Florida Gainesville FL 32611 USA). Berndt H. Yanez J. High-temperature hydraulic high- pressure nebulization a recent nebulization principle for sample introduction. J. Anal. At. Spectrom. 1996 11 703. (Inst. Spektrochem. und Angewandte Spektroskopie 441 39 Dortmund Germany). Augagneur S. Medina B. Szpunar J. Lobinski R. Determination of rare earth elements in wine by inductively coupled plasma mass spectrometry using a microconcentric nebulizer. J. Anal. At. Spectrom. 1996 11 713. (Lab. Interregional Repression Fraudes DGCCRF 33 405 Talence France). Kerl W. Becker J. S. Dietze H.-J. Dannecker W. Determination of iodine using a special sample intro- duction system coupled to double-focusing sector field inductively coupled plasma mass spectroscopy. J.Anal. At. Spectrom. 1996 11 723. (Zentralabteilung Chem. Anal. Forschungszentrum Julich GmbH 52425 Julich Germany). Veillon C. Patterson K. Y. Moser-Veillon P. B. Digestion and extraction of biological materials for zinc stable isotope determination by inductively coupled plasma mass spectrometry. J . Anal. At. Spectrom. 1996 11 727. (US Dept. Agric. Beltsville Human Nutrition Res. Center Beltsville MD 20705 USA). Poluzzi V. Cavalchi B. Mazzoli A. Alberini G. Lutman A. Coan P. Ciani I. Trentini P. Ascanelli M. Davoli V. Comparison of two different inductively coupled plasma mass spectrometric procedures and high-performance liquid chromatography with electro- chemical detection in the determination of iodine in urine.J. Anal. At. Spectrom. 1996 11 731. (Presidio Multizonale Prevenzione AUSL 42100 Reggio Emilia Italy). Bergdahl I. A. Schutz A. Grubb A. Application of liquid chromatography-inductively coupled plasma mass spectrometry to the study of protein-bound lead in human erythrocytes. J. Anal. At. Spectrom. 1996 11 735. (Dept. Occupational and Environ. Med. Univ. Hospital 221 85 Lund Sweden). Schickling C. Yang J. Broekaert J. A. C. The optimization of electrochemical hydride generation coupled to microwave-induced plasma atomic emission spectrometry for the determination of arsenic and its use for the analysis of biological tissue samples. J. Anal. At. Spectrom. 1996 11 739. (Dept. Chem. Univ. Dortmund 44221 Dortmund Germany). Einhauser T. J. Galanski M. Keppler B.K. Determination of platinum in protein-bound CDDP Journal of Analytical Atomic Spectrometry November 1996 Vol. 1 1 451 R9 61438 3 9614384 961438 5 9614386 96/43 8 7 9 6/43 8 8 9 614 3 8 9 9614390 96/4391 9614392 9614393 96/4 3 94 452 R and DBP by inductively coupled plasma optical emission spectrometry and electrothermal atomic absorption spectrometry. J. Anal. At. Spectrom. 1996 11 747. (Anorganisch-Chem. Inst. 69120 Heidelberg Germany). Rhoades C. B. Jr. Clean laboratory chemistry for the microwave-assisted digestion of botanical samples. J. Anal. At. Spectrom. 1996 11 751. (Bowman Gray Tech. Center R.J. Reynolds Tobacco Co. 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Digital pulse processing for peak enhancement in gas proportional scintillation counter X-ray fluores- cence spectra. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Physics Dept. Univ. Coimbra 3000 Coimbra Portugal). Gohshi Y. TXRF standard for measurement of Si wafer surface contamination. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Dept. Applied. Chem. Univ. Tokyo Tokyo Japan). de Koster C. G. Vanwersch J. M. H. Rousseau J. P. G. Characterization of thin foils of polymeric materials by energy dispersive-XRF. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Dept.Phys. Anal. and Computational Chem. DSM Res. 6160 MD Geleen Netherlands). Pinheiro T. Bugalho de Almeida A. Vieira J. Fernandes A. Alves L. C. Reis M. Carvalho Soares J. Elemental distribution in the human respiratory system and excretion organs-absorption and accumu- lation. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Nucl. and Technol. Inst. ITN Sacavem Portugal). Karydas A. G. Paradellis .T. Measurement of KL and LM resonant Raman scattering cross sections with a proton induced KolCr X-ray beam. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Inst. Nucl. Phys. NCSR Demokritos 153 10 Aghia Paraskevi Greece).Ropiger V. XRF analytical applications for industry using low cost proportional counter based instrument technology. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Helmut Fischer GmbH & Co. 71050 Sindelfingen Germany). Alves L. C. Reis M. A. Freitas M. C. Gouveia M. A. Elemental analysis of particulate matter and source profile in Lisboa. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Nucl. and Technol. Inst. 2686 Sacavem Codex Portugal). 20375-5352 USA). Journal of Analytical Atomic Spectrometry November 1996 VoE. 11 455 R9 6/C44 8 9 96/C4490 96/C449 1 96/C4492 96/C4493 96/C4494 9 6/C449 5 96/C4496 96/C4497 96/C4498 96/C4499 Delgado Martinez V.Mainardi R. T. Barrea R. A. Martinez Hidalgo C. Derosa P. A. Marco Abboli M. A parametric model for the efficiency curve of ger- manium detectors. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Catedra Fisica Med. Fac. Med. Univ. Complutense 28050 Madrid Spain). Somogyi A. Braun M. Comparison of the EDXRF and ICP AES techniques determining the trace element content of soil samples. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Isotope Lab. Kossuth Univ. 4010 Debrecen Hungary). Kump P. Necemer M. Veber M. Experimental criteria for critical sample thickness in total reflection X-ray analysis. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (J.Stefan Inst. 1001 Ljubljana Slovenia). Ellis A. T. Russell P. A. Benefits of digital signal processing in EDXRF spectrometry. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Ind. Anal. Group Oxford Instruments Abingdon Oxon UK OX14 1TX). Araujo M. F. Valerio P. Heavy metal assessment in sediments of the Ave River Basin (Portugal) by EDXRF. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Quim. ITN Estrada Nacl. 10 2685 Sacavem Portugal). Pasti F. Torboli A. Zanetti C. Ugazio G. Determination of pollutants increase in the sediment of Sangone River (tributary of the Po) by TXRF method. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Ital Structures 38066 Riva del Garda TN Italy).Mendoza A. Meltin J. J. Benitez F. Travieso L. de la Fuente F. Cesareo R. Multi-element analysis of microalgae by energy dispersive X-ray fluorescence. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29,1996 (Natl. Center Scientific Res. (CNIC) Havana Cuba). Osan J. Torok S. Deposition of vanadium containing particles from stack gas demonstration of applicability of EPMA single particle analysis and XRF. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (KFKI Atomic Energy Res. Inst. 1525 Budapest Hungary). Janssens K. Balis A. Van Hour N. Leland D. In- situ pigment analysis in paintings of Rubens and contemporaries by means of a portable ED-XRF spectrometer.European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Dept. Chem. Univ. Antwerp 2600 Antwerp Belgium). Cesareo R. Gigante G. E. Non-destructive analysis of ancient alloys by energy dispersive X-ray fluorescence systems. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (1st. Matematica e Fisica Univ. Sassari Sassari Italy). Calliari I. Magrini M. Zambon A. Martini R. EDXRF and SEM study of Roman coins preliminary results. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (D.I.M.E.G. Univ. Padua 35141 Padova Italy). Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (1st.Fisica Generale Applicata Univ. Studi 20133 Milano Italy). 96/C4502 Janssens K. Aerts A. Deraedt I. Vekemans B. Vincze L. Adams F. Use of microscopic x-ray emission techniques in the study of archeometrical and art objects. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Dept. Chem. Univ. Antwerp 2610 Antwerp Belgium). 96/C4503 Veloso J. F. C. A. dos Santos J. M. F. Morgado R. E. Conde C. A. N. Application of microstrip gas chambers to energy dispersive X-ray fluorescence analysis. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Dpto. Fisica Univ. Coimbra 3000 Coimbra Portugal ). 96/C4504 Brito J. Carvalho M. L. Study of trace elements concentration in human tissues by EDXRF.European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Centro Fisica Atomica Univ. Lisboa 1699 Lisboa Codex Portugal). 96/C4505 Ellis A. T. Russell P. A. Price B. J. Multi-dispersive XRF-a powerful combination? European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Ind. Anal. Group Oxford Instruments Abingdon Oxon UK OX14 1TX). 96/C4506 Pansky A. Breskin A. Chechik R. Particle induced sub-keV X-ray spectroscopy using a low-pressure electron counting detector. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Particle Phys. Dept. Weizmann Inst. Sci. Rehovot Israel). 96/C4507 Leiro J. A. Heinonen M. H. Shape of Ka1,2 X-ray emission spectra. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Dept.Applied Phys. Univ. Turku 20500 Turku Finland). 96/C4508 Wegrzynek D. Extended procedure of X-ray spectra fitting for EDXRF analysis. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Fac. Phys. and Nuclear Tech. Univ. Mining and Metallurgy 30-059 Krakow Poland). 96/C4509 Fernandez J. E. Bastiano M. Tartari A. Polarization effects in X-ray and y-ray spectrometry. European Conference on Energy Dispersive X-ray Sprectometry Lisboa Portugal June 23-29 1996 (Natl. Inst. Phys. Matter (INFM) and Lab. Montecuccolino Dept. Energetics Nuclear and Environ. Control Eng. Univ. Bologna 40136 Bologna Italy). 96/C45 10 Kallithrakas-Kontos N. Moshohoritou R.Speciation of vanadium compounds from their K X-ray line energy shifts. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Tech. Univ. Crete 73100 Chania Greece). 96/C4511 Mainardi R. T. Chesta M. A. Plivelic T. S. Positron induced characteristic X-ray lines emission. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Fac. Matematica Astronomia y Fisica Univ. Nacional Cordoba 5010 Cordoba Argentina). 96/C4512 Tartari A. Casnati E. Bonifazzi C. Paganetto G. Photon scattering by compounds an assessment of the validity of the independent atomic model approxi- mation. European Conference on Energy Dispersive 96/C4500 Filomena Guerra M. May XRF and PIXE solve archaeological and historical questions? The case of X-ray Spectrometry Lisboa Portugal,-june -23-29 1996 (Dept.Phvs. Univ. Ferrara. Italv). - . I - I metals. Ekopean Conference -on Energy Dispersive Spectrometry Lisboa Portugal June 23-29 1996 (CNRS Centre Recherches Ernest Babelon 45650 Orleans Cedex 2 France). 96/c4513 Hang N- T-9 Leermake% Ma Boman J. Trace element analysis of coal and impact of coal to the human health in Vietnam. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal. June 23-29. 96/C4501 Cicardi C. Milazzo M. Methods for EDXRF quanti- 1996 (Dipt. Hum.- Ecol. Vrije Unii. Brussels 1090 tative analysis of ancient metal objects. European Brussels Belgium). 456R Journal of Analytical Atomic Spectrometry November 1996 Vol. 1 196/C4514 Wielopolski L.XRS in biomedical applications. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Med. Dept. Brookhaven Natl. Lab. Upton NY 11973 USA). 96/C4515 Barreiros M. A. Carvalho M. L. Costa M. M. Marques M. I. Ramos M. T. TXRF application for elemental studies in drinking water. European Conference on Energy Dispersive X-ray Spectrl,metry Lisboa Portugal June 23-29 1996 (Dpto. Fisica Fac. Ciencias Univ. Lisboa 1699 Lisboa Codex Portugal). 96/C45 16 Holynska B. Total reflection X-ray fluorescence analysis of water and blood serum with chemical preconcen- tration. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Fac. Phys. and Nuclear Tech. Univ. Mining and Metallurgy 30-059 Krakow Poland).96/C4517 Wobrauschek P. Kregsamer P. Goergl R. Streli C. Pahlke S. Fabry L. Garbe S. Haller M. Knoechel A. Radtke M. TXRF with synchrotron radidion- analysis of various samples. European Confer€ nce on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Atominstitut Oesterreichischen Univ.. 1020 Wien. Austria). 961 ‘C4518 Goergl R. Kregsamer P. Streli Ch. Wobrauschek P. Aiginger H. A comparison of several excitation modes and geometries for total reflection X-ray fluorzscence with synchrotron radiation. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal. June 23-29. 1996 (Atominstitut 96/C4526 Figueiredo M. O. Basto M. J. Ramos M. T. Melo Z. Chevallier P. Milliprobe-scale geochemical analysis by X-ray fluorescence using synchrotron radiation.European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Centro Crist. Mineralogica 1000 Lisboa Portugal). 96/C4527 Kling A. Soares J. C. da Silva M. F. Kollewe D. Beck O. Krause H. Flagmeyer R.-H. Vogt J. Determination of impurity lattice sites in single crystals using PIXE channeling. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Centro Fisica Nuclear Univ. Lisboa 1699 Lisboa Codex Portugal). 96/C4528 Soares J. C. da Silva M. F. The PIXE technique in the Portuguese ion beam laboratory. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Centro Fisica Nuclear Univ. Lisboa 1699 Lisboa Codex Portugal). 96/C4529 Franco E.D. Ryon R. W. Vincze L. Janssens K. Capillary optics for microanalysis applications. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (ARACOR Sunnyvale CA 94086 USA). 96/C4530 Rindby A. Microbeam XRF analysis on highly irregu- larly shaped and inhomogeneous samples. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Dept. Phys. Chalmers Univ. Technol./Univ. Goeteborg 4 12 96 Goeteborg Sweden). Oesterureichischen Univ. 1020 Wien Austria). 96/C4531 Vincze L. Janssens K. Engstrom P. Rindby A. 96/C4519 Streli C. Wobrauschek P. Bauer V. Goergl R. Kregsamer P. Pianetta P. Ryon R. Light clement analysis with TXRF using synchrotron radiatim and special X-ray tubes.European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugrtl June 23-29 1996 (Atominstitut Oesterreichischen Univ. Larsson S. Focussing of synchrotron radiation by capillary optics theoretical modelling and experimental verification using the ESRF optical beamline. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29,1996 (Dept. Chem. Univ. Antwerp Antwerp Belgium). 1020 Wien Austria). 96/C4532 Vekemans B. Janssens K. Vincze L. Adams F. 96/C4520 Klockenkaemper R. Recent applications of totai reflec- Hertogen J. Segmentation and quantitative prepro- cessing of p-XRF image sets by means of clustering tion X-ray fluorescence. European Conferelice on Energy Dispersive X-ray Spectrometry Lisboa techniques. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Dept.Chem. Univ. Antwerp 2610 Antwerp Portugal June 23-29 1996 (Inst. Spektrocheln. und Belgium). Angewandte Spektroskopie 441 39 Dor tmund Germany). 96/C4521 Castellano A. Cesareo R. Marabelli M. A new portable instrument for EDXRF/analysis of sulfur in environmental samples. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Dipt. Sci. Material Univ. Lecce Lecce Italy). 96/C4522 Warren P. L. The selection of instrumentation for online XRF analysis. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugrtl June 23-29 1996 (Wilton Res. Centre ICI Middleshrough UK TS90 8JE). 96/C4523 Lepy M.-C. Ban G. Beck L. Dhez P. Plagnard J.Stemmler P. Study of the peak shape obtained with Si( Li) detector in the 1 to 7 keV energy range. Ebropean Conference on Energy Dispersive X-ray Spectrl>metry Lisboa Portugal June 23-29 1996 (Commissariat Energie Atomique Lab. Primaire Rayonriements Ionisants 91 193 Gif sur Yvette France). 96/C4524 Papp T. Campbell J. L. Maxwell J. A. Si(Li) detector lineshapes contributions from atomic physics and detector properties. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Dept. Phys. Univ. Guelph Guelpn Ont. Canada N1G 2W1). 96/C4525 Claes M. Van Grieken R. Comparison of grazing emission X-ray fluorescence with total reflection-XRF and other XRF techniques. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Dept.Chem. Univ. Antwerp 2610 Antwerpen Belgium). 96/C4533 Engstroem P. Rindby A. Janssens K. Combined p-XRF and p-XRD analysis of highly inhomogeneous samples on an undulator beamline at ESRF. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (E.S.R.F. 38043 Grenoble France). 96/C4534 Djupstroem Fridell M. Selin Lindgren E. Simpson D. Verification of air mass trajectories in long distance air pollution using elemental ratios. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Environ. Phys. Chalmers Univ. Technol./Univ. Goeteborg 412 96 Goeteborg Sweden). 96/C4535 Piorek S. Piorek E. Zepeck R. Continuous monitor- ing of heavy metals in stack emission particulates using energy dispersive X-ray spectrometry.European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Metorex Inc. Langhorne PA 19047 USA). 96/C4536 Van Grieken R. De Bock L. Hoornaert S. Characterisation of individual indoor and outdoor aerosol particles using EDXRS. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June 23-29 1996 (Micro- and Trace Anal. Centre Univ. Antwerp 2610 Antwerpen Belgium). 96/C4537 Bernasconi G. Dargie M. Haselberger N. Markowicz A. Tajanai A. Valkovic V. Developing reference materials for elemental analysis of airborne particulates. European Conference on Energy Dispersive X-ray Spectrometry Lisboa Portugal June Journal of Analytical Atomic Spectrometry November 1996 1/02.11 457R96/C45 3 8 96/C4539 96/C4540 96/C454 1 96/C4542 9 6/C4 5 4 3 96/C4544 96/C4545 96/C4546 96/C4547 96/C4548 23-29 1996 (Agency’s Lab. Seibersdorf Intl. Atomic Energy Agency 1400 Vienna Austria). Hu K. Luan S. van der Hoeff B. Zhyg Y. Kunselman G. Plasma optical emission mass spec- trometry (POEMS or ICP-MS/OES) theory and appli- cation. 5th National Conference on Atomic Spectroscopy May 12-16 1996 Wuhan China (Thermo Jarrell Ash Corp. Franklin MA 02038 USA). Golloch A. Genkel O. Moormann A. Seidel T. Sigmund D. Sliding spark spectroscopy fundamentals and applications. 5th National Conference on Atomic Spectroscopy May 12-16 1996 Wuhan China (FG Instrumental Anal. Chem. Univ. Duisburg 47048 Duisburg Germany). Yamasaki S. I. Development current status and future prospects of double focusing inductively coupled plasma mass spectrometers.5th National Conference on Atomic Spectroscopy May 12-16 1996 Wuhan China (Fac. Agric. Tohoku Univ. Sendai 981 Japan). Welz B. Gilmutdinov A. Kh. Sperling M. Spatially resolved spectroscopy in graphite atomizers or rewriting Beer’s law for GFAAS. 5th National Conference on Atomic Spectroscopy May 12-16 1996 Wuhan China (Dept. Applied Res. Bodenseewerk Perkin-Elmer GmbH 88647 Uberlingen Germany). Houk R. S. Elemental and isotopic analysis and measurement of elemental speciation by inductively coupled plasma mass spectrometry and electrospray mass spectrometry. 5th National Conference on Atomic Spectroscopy May 12-16 1996 Wuhan China (Dept. Chem. Ames Lab. U.S.Dept. Energy Iowa State Univ. Ames IA 50011 USA). Silva P. R. M. Dorea J. G. Multielement determi- nation in small samples of human milk and blood serum by inductively coupled plasma spectroscopy. 4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22 1996 (Dept. Chem. Univ. Brasilia 04322 Brasilia Brazil). Belliveau J. f. Huwel L. Cadwell L. H. Evaluation of laser induced breakdown spectroscopy (LIBS) for trace metal analysis of live tissue. 4th International Syposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22 1996 (Providence Coll. Providence RI 02918 USA). Jorgenson D. S. Centeno J. A. Mayer M. H. Manson P. N. Analytical evaluation of local tissues surrounding titanium implants. 4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22 1996 (Walter Reed Army Med.Center Washington DC USA). Grime G. W. McDonald B. Triffet J. R. Dagg B. Metal localisation in biological materials using the nuclear microprobe. 4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22 1996 (SPM Unit Univ. Oxford Oxford UK). Hagen W. R. Recent advances in EPR spectroscopy of biological metal centers. 4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22 1996 (Wageningen Agric. Univ. and Univ Nijmegen Netherlands). Figueras M. J. Moncusi M. Mayayo E. SEM- mapping X-ray microanalysis of embedded material. An alternative technique to bulk (SEM) and STEM microanalysis. 4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22 1996 (Unit Microbiol.Univ. Rovira Virgili 43201 Reus. SDainL 96/C4550 Maroney M. J. Gu Z. Choudhury S. B. Allan C. B. X-ray absorption spectroscopy a structural probe of biological metal sites. 4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22 1996 (Univ. Massachusetts Amherst MA 01003 USA). 96,424551 Cocchietto M. Mestroni G. Alessio E. Sava G. Determination of ruthenium by atomic absorption spectroscopy after treatment with Na [trans- RuCl,( DMSO)lm]. 4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22 1996 (Fondazione Callerio Inst. Biol. Res. Univ. Trieste 34127 Trieste Italy). 96/C4552 Szokefalvi-Nagy Z. Ion beam analysis of metallo- proteins.4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22 1996 (KFKI Res. Inst. Particle and Nuclear Phys. 1121 Budapest Hungary). 96/C4553 Homma-Takeda S. Ishido M. Kumagai Y. Takeneka Y. Shimojo N. In situ determination of mercury distribution and apoptotic cells in mercury-treated rat kidney by a combination of synchrotron radiation x-ray fluorescence (SR-XRF) imaging and TUNEL staining. 4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22 1996 (Dept. Environ. Med. Inst. Community Med. Univ. Tsukuba Ibaraki 305 Japan). 96/C4554 Feenstra O. Pridnig G. Drasch G. Rodier G. Association of blood cadmium levels to cigarette smoking in an environmentally cadmium-exposed population. 4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22 1996 (Dept.Environ. Health Klagenfurt Austria). 96/C4555 Bastos M. L. Soares M. E. Ferreira M. A. Quantification of total chromium and Cr(v1) in rat liver by electrothermal atomization atomic absorption spectrometry. 4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22 1996 (CEQUP Fac. Farm. Univ. Porto 4050 Porto Portugal). 96/C4556 Baranowski J. Baranowska I. Meconium analysis using AAS for screening the intrauterine exposure to heavy metals in an ecological disaster region.. 4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22,1996 (Neonatal Clinic Silesian Med. Univ. Zabrze Poland).96/C4557 Palsgard E. Grime G. W. Nuclear microprobe imaging of the distribution of metal ions in insulin producing cells. 4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22 1996 (SPM Unit Nuclear Phys. Lab. Univ. Oxford Oxford UK). 96/C4558 Lazof D. B. Goldsmith J. G. Linton R. W. In situ ion transport nutritional and toxic metal SIMS studies. 4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22 1996 (Dept. Chem. Univ. North Carolina Chapel Hill NC 96/C4559 Lavilla I. Perez Cid B. Bendicho C. Comparison of acid digestion methods (conventional and microwave) for the determination of metal ions in plants samples. 4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain May 19-22 1996 (Vigo Univ.32004 Ourense Spain). 96/C4560 Suzuki K. T. Itoh M. Ohmichi M. Selenium-specific biological indexes for selenium-demand by HPLC/ ICP-MS with enriched stable isotope. 4th International 27599-3290 USA). I I I -~ ~ Symposium on Metal Ions in Biblogy + Medicine Barcelona Spain May 19-22 1996 (Fac. Pharm. Sci. 96/C4549 Gelinas Y. Schmit J.-P. Multielement analysis of human foetal tissues by inductively coupled plasma- Chiba Univ. Chiba 263 Japan). mass spectrometry. 4th International Symposium on Metal Ions in Biology + Medicine Barcelona Spain 96/C4561 Sabbioni E. In uitro approaches to metal toxicology May 19-22,1996 (Dept. Chim. Univ. Quebec Montreal research at the JRC-ISPRA. 4th International Montreal Que. Canada H3C 3P8). Symposium on Metal Ions in Biology + Medicine 458R Journal of Analytical Atomic Spectrometry November 1996 Vol.1196/C4562 96/C4563 96fC4564 96fC4565 96,424566 96fC4567 96/C4568 96fC4569 96/C4570 96fC457 1 96/C4572 96/C4573 96/C4574 Barcelona Spain May 19-22 1996 (European Commission Environ. Inst. 21029 Ispra (Varese). Italy). Chandra S. Subcellular imaging of metal ions and the application of stable isotopes for measuring the influx of calcium ions and molecules in single cc4s by secondary ion mass spectrometry. 4th International Symposium on Metal Ions in Biology + Mcdicine Barcelona Spain May 19-22 1996 (Dept. Chem. Cornell Univ. Ithaca NY 14853 USA). Lavilla I. Perez Cid B. Bendicho C. Evaluation of the extraction capability of metal ions from plants using ultrasonic processing.4th International Symposium on Metal Ions in Biology + Mtbdicine Barcelona Spain May 19-22 1996 (Vigo Univ. 32004 Ourense Spain). Rietz B. The use of INAA and ICP-MS for the determination of aluminium in fish tissues-a compari- son. The 15th Nordic Atomic Spectroscopy anc Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Isotope Div. Riso Natl. Lab. 4000 Roskilde Denmark). Hutton R. C. Smith F. G. Watson P. Matrix elimination systems for ICP-MS. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (CETAC Technologies Inc. Crewe Cheshire UK CW 1 1 YX). Merten D. Broekaert J. A. C. Application of the image system for analyses of materials with line rich emission spectra by sequential ICP-OES. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Dept.Chem. Univ. Dortmund 44221 Dortmund Germany). Jalkanen L. ICP-MS in the research of atmospheric pollutants. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Air Quality Res. Finnish Meteorological Inst. 00810 Helsinki Finland). Mathe D. Focused microwave technology in analytical chemistry. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmarh June McCrum M. Automatic burner rotation (ABRI main- tains accuracy precision and reproducibility removing the need for manual dilution. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (GBC). Odman F. Ruth T.Ponter C. Validation of a method for determination of total concentrations of lantk anoids and some actinides in suspended particulate matter from freshwater. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Div. Applied Geol. Lulea Univ. Technol. 971 87 Lulea Sweden). Magnusson B. Analysis of samples from a pulp mill with ICP and XRF. The 15th Nordic itomic Spectroscopy and Trace Element Conference E beltoft Denmark June 2-6 1996 (Central Anal. Lah. Eka Chemicals 445 80 Bohus Sweden). Sturgeon R. E. FAPES source diagnostics and analyt- ical applications. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Inst. Natl. Measurement Standards Natl. Res. Council Canada Ottawa Canada K1A OR9).Stroh A. Georgitis S. J. Plantz M. Anderson S. Shaw P. Tyler G. Recent advances in cool plasma work to achieve sub-ppt detection limits for Fe and Ca. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Varian Instruments North America ). Stuerup S. Elemental trace element analysis in biologi- cal samples by high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). The 15th 2-6 1996 (PROBLABO). 96fC45 75 96/C4576 96fC4577 96/C45 7 8 96fC4579 96/C4580 96/C4581 96fC4582 96/C4583 96,424584 96/C45 85 96/C4586 96/C4587 Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Riso Natl. Lab. Denmark). Sigsworth P. Abell I. Fahlander M. New application for a third generation quadrupole ICP-MS.The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (VG Elemental Winsford Cheshire UK CW7 3BX). Mullins C. B. An improved method of sample introduc- tion for flame atomic absorption spectroscopy. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Varian Optical Spectroscopy Instruments Europe Walton-on- Thames Surrey UK KT12 2QF). Hansen E. H. Flow injection analysis and atomic absorption spectrometry-an attractive and powerful analytical chemical combination. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Dept. Chem. Tech. Univ. Denmark 2800 Lyngby Denmark). Bloedorn W. Speciation analysis with the compound system LC-ICP.The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (SPECTRO Anal. Instruments 47533 Kleve Germany). Snell J. P. Frech W. Thomassen Y. Trace determi- nation of mercury species using an amalgamation trap with capillary gas chromatography-microwave induced plasma-atomic emission spectrometry. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Dept. Anal. Chem. Umea Univ. 901 87 Umea Sweden). Larsen E. H. Pedersen G. A. Speciation of selenium and arsenic in food by HPLC coupled with electrospray MS-MS or ICP-MS. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Natl. Food Agency Denmark 2860 Soborg Denmark). Hanstrom S.Emteborg H. Baxter D. C. Large volume injections in capillary gas chromatography using a separately heated packed pre-column appli- cation to mercury speciation in natural water. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Dept. Anal. Chem. Umea Univ. 901 87 Umea Sweden). Oughton D. The use of tracers in speciation studies. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Lab. Anal. Chem. Agric. Univ. Norway 1432 As Norway). Francesconi K. A. The importance of arsenic speciation in environmental and human health research. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Inst. Biol. Odense Univ. 5230 Odense Denmark). Paul M. Vollkopf U.Excimer lasers the state-of-the- art technology in laser sampling ICP-MS. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Bodenseewerk Perkin-Elmer GmbH 88647 Uberlingen Germany). Svanberg S. Chemical analysis by laser spectroscopy. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6,1996 (Lund Laser Centre Lund Univ. 22100 Lund Sweden). Donard 0. F. X. Speciation of trace metals progress in atomic spectrometry and environmental implications. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Lab. Chim. Bio-Inorg. Environ. Univ. Pau Pays 1 64000 Pau France). Ebdon L. Getting it right. The role of sample preparation in coupled techniques with ICP-MS.The Journal of Analytical Atomic Spectrometry November 1996 Vol.11 459 R15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 Anal. Chem. Univ. Gent Gent Belgium). Drake Circus Plymouth UK PL4 8AA). Conference Ebeltoft Denmark June 2-6 1996 (Lab. 96/C4589 Sturgeon R. E. Reference materials and the National Research Council of Canada. The 15th Nordic Atomic Spectroscopy and Trace Element Conference Ebeltoft Denmark June 2-6 1996 (Inst. Natl. Measurement Standards Natl. Res. Canada Ottawa Ont. Canada Unity Univ. 96/C4588 Cornelis R. The analytical challenge speciation of trace elements in biological fluids and tissues. The 15th Nordic Atomic Spectroscopy and Trace Element K1A OR9). 460 R Journal of Analytical Atomic Spectrometry November 1996 Vol.1 1

ISSN:0267-9477    

DOI:10.1039/JA996110443R

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

Characteristics of an Inductively Coupled Argon Plasma Operating With Organic Aerosols Part 4. Noise Power Spectra* D. G. WEIRt AND M. W. BLADES* Department of Chemistry University of British Columbia Vancou;)er British Columbia Canada V6T 1 Z l With the use of noise power spectra it is shown that the vortex shedding frequency depends on the solvent and the solvent plasma load and modulates both the plasma boundary and analyte plume of the discharge. Keywords Inductively coupled argon plasma; organic solvent; solvent plasma load; noise power spectra This paper is the fourth part in a series on the physical characteristics of an inductively coupled argon plasma ( ICAP) operating with organic aerosols. The previous papers surveyed both the parametric and structural complexity of the ICP discharge and examined solvent load effects in both parameter space (gas flow rates applied power solvent load etc,.) and physical space (spatial zones).The first part described the experimental system for making spectral spatial and temporal measurements and examined the effect of solvent and solvent load on the background spectra and visual features of an ICAP in general.' The second documented the effect of chloro- form load on the axial emission spatial profiles for C I C and CN (background species) and Mg I Mg I1 (analyte species) and the ratio of Mg I1 to Mg I. The third presented the effects of solvent and solvent load on the radial spatial emission profiles of these same specie^.^ The present paper examines systematic trends in noise power spectra. Temporal fluctuations are known to occur in the ICP.Probably the two most important of these fluctuations result from vortex shedding beyond the exit of the torch and droplet vaporization within the axial channel. For the latter it has been shown that relatively large droplets (approximately 25 pm in diameter) of an aqueous aerosol can actually survive in the plasma all the way up to the analytical viewing zone (z= 15 mm above the induction Although these large droplets are statistically few in number they are significant in volume and thus can contain a significant amount of analyte and solvent material compared with the rest of the aerosol. When such large droplets are swept along by the argon stream their solvent evaporates and cools small regions of the sur- rounding plasma.When such regions of local cooling pass through the viewing zone they cause the emission signal to fluctuate aperiodically on the sub-millisecond time scale. Similar fluctuations result when relatively large particles left behind by the large droplets pass through the viewing zone because they are surrounded by local concentrations of analyte vapour. In general the fluctuations resulting from aerosol vaporizadon are aperiodic and alter plasma conditions on the sub-millisecond time scale. In contrast to vaporization events vortices set up periodic * For Parts 1 2 and 3 of this series see references 1 2 and 3 Present address 10228 109 Street Fort Saskatchewan Alberta respectively. Canada. * To whom correspondence should be addressed. Journal of Analytical Atomic Spectrometry fluctuations when they shed off the plasma jet modulating the emission signal at approximately 200 Hz.Experimental evi- dence suggests that vortices modulate both the outer boundary of the discharge and the flow field within the plasma. In fact it appears as if vortices peristaltically pinch the flow of the axial channel as they shed off the plasma jet.' At any rate it is clear that both vortex shedding and aerosol vaporization disrupt the flow field and temperature field of the discharge. Walden et ~ 1 . ~ and Belchamber and Horlick" studied the noise in the analyte signal of the ICP by examining its noise power spectrum. A noise power spectrum can be obtained by sampling the emission signal at an appropriate rate and then taking the Fourier transform of the time varying part.Next different frequency components of the noise such as llfnoise white noise whistle noise and power-line noise can all be identified and then traced back to their respective sources such as a defective power supply the gas-flow dynamics of the discharge or nebulizer drift. Talmi et al." have already applied this approach to other spectrochemical sources and found that it was a powerful method for isolating sources of noise in spectrochemical methods. Belchamber and Horlick" obtained noise power spectra of the analyte emission signal from an ICAP and identified several distinct components of the noise. For example they identified a low-frequency component which they attributed to sample flicker or llf fluctuations of the analyte transport efficiency.They also identified an acoustic component which they con- cluded was due to plasma rotation. They were led to this conclusion by the results of an interesting experiment. Essentially they used two monochromators and detectors to monitor signal fluctuations from an ICAP simultaneously via two optical channels. One optical channel viewed the discharge at 90" with respect to the other. Remarkably the acoustic fluctuations for the two channels were 90" out of phase. Evidently the plasma was rotating or so they concluded. Winge et al. later demonstrated that the acoustic frequency noise at w 200 Hz resulted from vortex shedding.12 This con- clusion has been corroborated by the noise power spectra reported by Winge et al.,I3 Hieftje et al.,14*15 Furuta et a1.,16 Davies and Snook17 and Goudzwoard and de Loos- Vollebregt." Of all this work Winge et ~ 1 .' ~ provided the most convincing evidence for the vortex shedding phenomenon. They found that the acoustic noise band at w200 Hz disap- peared when the outer tube of the ICAP torch was extended by 6 mm. The extension prevented air from entraining into the argon stream and hence suppressed vortex shedding. Consequently the acoustic noise band at M 200 Hz disappeared from their noise power spectra for the extended torch. They went further by capturing images of shedding vortices with a high-speed movie camera. The shedding frequency revealed by the movie frames matched a peak in their noise power spectra. Although this finding proved that vortex shedding was respon- sible for the acoustic bands discovered earlier by Walden et a[.' Journal of Analjitical Atomic Spectrometry November 1996 Vol.11 (I 01 1-1 01 8) 101 1and Belchamber and Horlick," it should be noted that vortex shedding and plasma rotation are not mutually exclusive. For example if the vortices were asymmetric then the rotation imparted to them by the tangential argon flow would be evident as a phase shift. Hence the shedding of asymmetric vortices is consistent with the results of Belchamber and Horlick's dual optical channel experiment." In addition to the vortex shedding phenomenon noise power spectra have revealed the effects of droplet vaporization. Noise spectra reported by Antanavicius et all9 demonstrated that broad-band noise (0-2.5 kHz) in ion-line signals may be attri- buted to aerosol vaporization.In typical noise power spectra however this broad-band noise is buried beneath the baseline of white noise. However Antanavicius et al. lowered the white- noise level in their spectra by suppressing the shot noise of their ph~tomultiplier.'~ In order to do that they used high concentrations of test analyte. These concentrations yielded large fluxes in radiation for the analyte signal and allowed them to suppress the photomultiplier shot noise by turning down the photomultiplier gain. After suppressing the white noise they compared noise spectra for test analyte introduced as vapour with those for test analyte introduced in an aqueous aerosol. They found that for the frequency range between 0 and 2.5 kHz the noise for aerosol introduction exceeded the noise for vapour introduction by an order of magnitude.In short they demonstrated that aerosol vaporization may be investigated with noise power spectra provided large concen- trations of test analyte are used. They suggested that the time scale of the vaporization event (500 ms) corresponded to the inverse of the noise bandwidth (2.5 kHz) and offered two explanations. A time scale of 500 ms could correspond to the pulse relaxation time of the analyte signal. In that case the wave form of the pulse would be determined by the vaporiz- ation of analyte particles and the pulse duration would follow Poisson statistics. On the other hand 500 ms could be the observation time of the flowing aerosol (after Eckert2').In that case one must assume that emitting particles survive the entire distance over the observation window. Interestingly one obtains a particle velocity of 20 m s-' when one divides their observation distance (slit height) of 10 mm by the time scale of 500 ms. This velocity agrees fairly well with typical centre- line velocities in the ICAP. The present paper discusses features of the noise spectra measured over the frequency range 0-500 Hz. Three param- eters were explored solvent solvent load and observation height. Evidence for vortex shedding is evident in all spectra that span acoustic frequencies above 100 Hz. It is shown that the vortex shedding frequency exhibits a dependence on solvent and solvent load in the plasma. EXPERIMENTAL The instrumentation and procedure for igniting the plasma generating the solvent aerosol preparing solutions controlling the operational parameters and measuring spectroscopic quan- tities have been presented in previous papers.'32*21922 All transi- ent signals were detected with a Hammamatsu R955 photomultiplier fitted to the 1 m Czerny-Turner monochroma- tor.The voltage applied to the photomultiplier was set to 600 V (yielding a photomultiplier gain FZ lo5) and the output was amplified by a Keithley 428 current amplifier. The amplifier gain was generally set to lo6 but gains of lo5 and lo7 were also used. The built-in low-pass filter .of the Keithley 428 current amplifier prevented high-frequency noise from being aliased into the noise spectra. The cut-off frequency was taken as the reciprocal of the filter rise time and the signal was sampIed at the Nyquist frequency or twice the cut-off fre- quency.For example when the 0-500 Hz frequency range was investigated the filter rise time was set to 1 ms giving a cut- off frequency of 1 kHz. Consequently the signal was sampled at 2 kHz. For these settings the -3 dB point of the filter response was at 350Hz and the filter response rolled off at -60 dB per decade (- 18 dB per octave). Note that much sharper cut-off filters are available but the built-in filter was adequate. Data were sampled using the RC electronics Compuscope software and ISC-16 data-acquisition board. The DADiSP worksheet (DSP Development) was used to calculate the noise power spectra. In general transients 16 K long were sampled then divided into 16 records of 1024 samples each.For each 1 K record the dc component was first removed by subtracting the mean signal. Then the time-varying component was apodized with a Hanning window. A fast Fourier transform was then taken and the sum of the squares of the real and imaginary parts gave the noise power spectrum. An average of the 16 resulting noise power spectra gave a good estimate of the noise power spectrum for the original 16 K transient. Finally the noise power or noise spectral density S was expressed in a variety of units so the average noise spectra could be compared with literature results. The results were expressed in decibels where the decibel scale represents the ratio of the noise amplitude A to the dc photocurrent A dB E 20 log(A/A,).This facilitated comparison with results from Winge et The discharge was imaged onto the entrance slit with an image to object ratio of 2 1 and the slit height was 1.5 mm so the projected aperture of the slit height was 3 mm. Winge et discussed how this dimension limits the spatial sampling frequency of periodic plasma fluctuations travelling past the observation zone. They pointed out that if the wavelength of a periodic plasma fluctuation was equal to the projected slit height then the fluctuation would be totally attenuated to the dc level. As it happens a projected slit height of 3 mm yields an effective spatial sampling frequency of approximately 3000 Hz when the wave velocities of typical periodic plasma fluctuations (10 m s-') are taken into account. The Winge et al.publication,12 should be consulted for further discussion of how both the spatial filtering of the slit-height aperture and the time-domain filtering determine the overall frequency response of the measuring system. The observation height was varied by translating the 1.5 mm slit-height aperture over the entrance slit. Neither the spatial response of the photomultiplier nor the spherical aberration of the lens were taken into account. Emission signals of the Mn I1 (257.61 nm) line and the CN (388.34 nm) bandhead were sampled at 2000 Hz to investigate the 0-500 Hz frequency range where vortex fluctuations can be expected. Emission signals of the Ca I (422.70 nm) line and the Mg I (285.22 nm) line were sampled at 200 kHz to investi- gate both the form of sub-millisecond transients and the 0- 100 kHz frequency range where droplet vaporization effects can be expected.Finally the emission signal from the C2 (516.56 nm) bandhead was sampled at 100 Hz to investigate low-frequency pulsation's owing to the peristaltic pump. In these studies spikes were not observed under the typically 'robust' operating conditions of the ICAP used in the present experiments for aqueous solvents nor were they observed for any of the organic solvents used. Loadings using methanol and chloroform were examined for the present paper. The chloroform load was varied from 3.2 to 10mg s-l and the methanol load from 0.3 to 0.7 mg s-'. The metal concentrations were 20 pg ml-I (20 ppm) in chloroform and methanol (as 2,4-pentanedionates).RESULTS AND DISCUSSION Figs. 1 to 4 are noise spectra for the Mn I1 (257.6 nm) line emission and CN (388.3 nm) bandhead emission from a solvent loaded ICAP. Noise spectra are shown at three viewing heights 101 2 Journal of Analytical Atomic Spectrometry November 1996 Vol. 11-50 ? I I I I 200 300 400 A 0 $ 0 200 300 400 .- 0 Z I “.L 100 260 300 400 Frequency/Hz Fig. 1 z=(a) 18 (b) 12 and (c) 6 mm Noise power spectra for Mn I1 257.610 nm as a function of chloroform solvent plasma load at the following heights above the load coil above the induction coil z=6 12 and 18 mm. Fig. 1 shows the response of the Mn I1 (257.6 nm) noise spectra to chloro- form load; Fig. 2 the response of the CN (388.3 nm) noise spectra to chloroform load; Fig.3 the response of the Mn I1 (257.6 nm) noise spectra to methanol load; and Fig. 4 the response of CN (388.3 nm) to methanol load. Clearly all of the noise spectra evolve in the same way with viewing height. In general an acoustic noise band at z 200 Hz dominates the spectra at all viewing heights. A sub-harmonic and two harmonics of the 200 Hz band emerge at 12 mm then become comparable in magnitude to the 200 Hz band at z= 18 mm. This evolution of acoustic noise with height is typical of the vortex shedding phenomenon for ICAPs sustained in short torches. The f/2 sub-harmonic of the 200Hz band first emerges in the z = 6 mm spectra. It becomes more intense at z = 12 mm and is joined by 3/2f and 2f harmonics at 18 mm. An expla- nation for the f/2 sub-harmonic was found by Winge et al.12 Their high-speed black and white movies revealed that vortex shedding alternates between strong and weak fluctuations.On the other had the 3/2f and 2f harmonics emerge when the varicose wave begins to crest. This happens immediately before the wave rolls over into a vortex. Note that additional harmon- ics are required to describe the wave as it crests because its Journal of Analytical Atomic Spectrometry November 1996 Vol. 11 101 3Fig.2 z=(u) 18 (b) 12 and (c) 6 mm Noise power spectra for CN 388.340nm as a function of chloroform solvent plasma load at the following heights above the load coil waveform clearly departs from a simple sinusoidal function. Above z = 18 mm the cresting wave rolls over into a vortex. When this happens Winge et a1.I’ found that 5/2f and 3f harmonics emerged.Undoubtedly these additional frequency components are required to describe the evolving waveform as it departs even further from a simple sinusoidal function. All of the 0-500Hz noise spectra evolved in this way. The only difference between the CN and Mn I1 spectra was a flicker component below 100 Hz displayed by the Mn I1 spectra at z = 6 mm. This l/f noise probably resulted from sample flicker (drift and low-frequency fluctuations in the aerosol transport efficiency) but not from droplet vaporization. In any case the 1,” components in these spectra are far weaker than those reported in the literature. Interestingly the noise spectra reported in the literature were without sample desolv- ation. Evidently the low levels of llf noise in Figs.1-4 corroborate what Maessen et a1.23324 observed i.e. that the desolvating condenser filters out the sample flicker noise. Of course one must also remember that the dependence of sample flicker on the design of the pneumatic nebulizer is fairly sensitive. Perhaps the MAK nebulizer is inherently quiet.25 101 4 Journal of Analytical Atomic Spectrometry November 1996 Vol. 11Fig. 3 Noise power spectra for Mn 11 257.610 nm as a function of methanol solvent plasma load at the following heights above the load coil z=(u) 18 (b) 12 and (c) 6 mm Apart from the llfcomponent the similarity between the noise spectra for Mn I1 emission and CN emission was unanticipated. While the CN noise reveals fluctuations in the boundary region where one would expect vortex shedding to prevail one would expect the Mn I1 emission from the analyte plume to be removed from processes in the boundary region.On the contrary vortex shedding modulates both the analyte plume and the boundary region to the same extent. Evidently the varicose instability is not confined to the boundary regions but penetrates right down to the axial channel. For an insight into how this happens one must go beyond noise spectra. The high-speed photographs reported by Winge et all2 revealed that shedding vortices pinch the analyte plume of the ICAP. A clearer picture of how shedding vortices affect the flow field is provided by the large body of work on axisym- metric jets. This work revealed that ring vortices constrict the flow along the axis of the jet.Between successive vortices the axial flow is forced radially outwards. In fact experimental results suggest that shedding vortices bunch the material flowing along axis into packets. One experiment revealed that particles in an axisymmetric particle laden jet are bunched together between successive vortices.26 Jozmal of Analytical Atomic Spectrometry November 1996 Vol. 11 101 50 100 200 300 400 7 a - S -304 ' I 1 Freq uency/Hz Fig. 4 Noise power spectra for CN 388.340 nm as a function of methanol solvent plasma load at the following heights above the load coil z= (a) 18 (b) 12 and (c) 6 mm Although the vortex shedding frequency is independent of viewing height in Figs. 1 to 4 the graphs in Fig. 5 show that it decreases with solvent plasma load. Moreover the decrease is far steeper for a methanol load than for a chloroform load.In order to explain this response and reconcile it with reports that the frequency increases with rf power outer argon flow rate and a short extension (1 cm) of the outer tube it is instructive to review vortex shedding in plasma jets briefly. A wealth of insight into vortex shedding has been provided by experimental and theoretical work with axisymmetric jets and diffusion flames. Several reports of this work are worth noting. Prandt127 provided a good introduction to the back- ground from a fluid mechanical standpoint while Becker and Massaro2* examined vortex evolution in a round (axisym- metric) plasma jet. Becker and Massaro illuminated the axisym- metric jet through a slit in order to obtain images of the flow structure for a narrow slice through the jet. Because the jet was laden with oil condensation smoke and because the light was stroboscopically synchronized with the vortex shedding they were able to obtain sharp phase-averaged photographs of the sagital cross-section of the jet. These photographs clearly revealed how the vortex structures evolve as they travel downstream.Moreover they revealed how vortex shedding varies as the Reynolds number is increased from 600 to 20000 and how the structured laminar flow of the vortices break down into turbulence (the ICAP occupies a flow regime of 101 6 Journal of Analytical Atomic Spectrometry November 195'6 Vo2. 11Chloroform load .g v) 184 laof 2 176- 8 172 \ Methanol load Fig.5 Effect of solvent plasma load on the vortex shedding frequency Re =200-600). In fact the phase-averaged photographs of the smoke-laden jet are far clearer than high-speed photographs of the ICAP because the exposure is more even (neither under- nor over-exposed) and the boundaries of the flow structures are sharp. Similar studies and photographic results have been published by Subbarao and Cant~ell,,~ Longmire and Eaton,26 Chen et aL3' and Dahm et aL3l The last workers measured laser-induced fluorescence images of coaxial jets. These images revealed how vortex formation may be attenuated by surround- ing the jet with an outer sheath flow. Roquemore et aL3' supplied 2D photographs of a diffusion flame illuminated by a sheet of laser light. The laser light was scattered off TiO particles formed by TiCl in the fuel and air reacting with combustion products. Their images revealed flow structures both at the outer boundary of the jet (visualized by TiO particles) and close to the axis (visualized by combustion). Interestingly the inner combustion region and outer vortex structures of a diffusion flame resembled the pinched analyte plume and shedding vortices of the ICAP.Further insight into the inner flow field is provided by Longmire and Eaton's study of a particle-laden jet.26 Although the flow regimes they studied corresponded to Reynolds numbers much higher than in the ICAP the velocity and density information they obtained from their laser Doppler anenometry experiment revealed much about how the axial flow of a jet interacts with ring vortices shedding off the periphery.Finally Subbarao and Cantwell provided stroboscopic Schlieren photographs of jets with Reynolds numbers in the immediate vicinity of the IC'AP.29 Although their photographs only revealed the flow Lit the interface between their helium jet (the jet was buoyant) and coflowing air the sharp Schlieren images revealed the vortex structure clearly. Fig. 6 is a schematic view of how the vortex-shedding process takes place in the ICAP. The six frames in the figure correspond to different phases of the vortex train. The drawings were based on the photographs reported by Winge et a1.,I2 and 18 12 6 0 Fig. 6 Schematic diagram of the vortex shedding mechanism for the ICP. The phase averaged view is shown on the left side of each frame.The right side of each frame shows the integrated time averaged view. The analyte plume is shaded gray the argon plasma is white and the downstream boundary is hatched compare the typical time-averaged view of the discharge with the phase-averaged view. Evident in the figure is the peristaltic pinching of the analyte plume. The wave velocity of the varicose disturbance is roughly half the velocity of the coolant stream. Consequently any variation in the operating parameters that increases the velocity of the coolant stream also increases the shedding frequency. An increase in the outer stream velocity can be explained in terms of two properties (i) how much argon is carried by the outer stream; and (ii) how effectively the hot plasma transfers heat to the argon in the outer stream and thereby accelerates the outer stream.Increasing the rf power increases the shedding frequency by accelerating the coolant stream i.e. more heat is transferred to the coolant stream. Increasing the outer flow increases the shedding frequency at first because a greater volume of coolant argon must flow through an outer annulus of constant area. However with further increase the outer flow ultimately levels off. It may even reverse as more energy is lost through convection from the discharge and the induc- tion region can no longer accelerate the outer flow as effectively by transferring heat to it. Similarly an increase in solvent plasma load consumes plasma energy and decreases the ability of the plasma to accelerate the outer stream.This effect is more pronounced for a methanol load because the plasma lifts and contracts axially.' As a result the axial distance over which the coolant stream comes into contact with the induction region decreases with methanol load. Far less heat can be transferred to the outer stream over shorter distances. The converse argument applies to extending the outer tube by 1 cm (Winge et al. observed that this increases the shedding fre- quency12). A 1 cm extension of the outer tube confines the outer flow next to the hot plasma for a longer distance so the outer flow accelerates more than in a shorter torch. Alternatively the frequency dependence could be explained in terms of the area of the unobstructed annulus through which the outer stream must escape past the plasma.This area would vary with the dimensions of the plasma. In reality the true mechanism by which the outer stream velocity and shedding frequency vary is probably a combination of both the heat transfer efficiency and the geometry of the discharge. CONCLUSIONS Vortex shedding is always present in torches without extension tubes and the phenomenen causes a modulation of emission in the ICAP. It has been observed that the vortex shedding frequency depends on the solvent and the solvent plasma load and modulates both the plasma boundary (measured using CN emission) and analyte plume of the discharge to a similar extent. The overall effect of a decrease in solvent plasma load on the vortex shedding frequency is similar to the effect of changes in rf power as described by Winge et al.who observed that the shedding frequency increased as the rf power was increased.12 The authors acknowledge funding from the Natural Sciences and Engineering Research Council of Canada. REFERENCES 1 Weir D. G. and Blades M. W. J. Anal. At. Spectrom. 1994 9 1311. 2 Weir D. G. and Blades M. W. J. Anal. At. Spectrom. 1994 9 1323. 3 Weir D. G. and Blades M. W. J. Anal. At. Spectrom. 1996,11,43. 4 Cicerone M. T. and Farnsworth P. B. Spectrochim. Acta Part B 1989 44 897. 5 Olesik J. W. Smith L. J. and Williamsen E. J. Anal. Chem. 1989 61 2002. 6 Olesik J. W. and Williamsen E. J. Appl. Spectrosc 1989,43,933. Journal of Analytical Atomic Spectrometry November 1996 Vol. 11 101 77 8 9 10 11 12 13 14 15 16 17 18 19 20 Olesik J.W. and Fister J. C. Spectrochem. Acta Part B 1991 46 851. Olesik J. W. and Fister J. C. 111 Spectrochim. Acta Part B 1991 46 869. Walden G. L. Bower J. N. Nikdel S. Bolton D. I. and Winefordner J. Spectrochim. Acta Part B 1980 35 535. Belchamber R. M. and Horlick G. Spectrochim. Acta Part B 1982 37 17. Talmi Y. Crosmun R. and Larson N. M. Anal. Chem. 1976 48 326. Winge R. K. Eckels D. E. DeKalb E. L. and Fassel V. A. J. Anal. At. Spectrom. 1988 3 849. Winge R. K. Crain J. S. and Houk R. S. J. Anal. At. Spectrom. 1991 6 601. Furuta N. Monnig C. A. Yang P. and Hieftje G. M. Spectrochim. Acta Part B 1989 44 649. Sesi N. N. Galley P. J. and Hieftje G. M. J. Anal. At. Spectorn. 1993 8 65. Furuta N. J. Anal. At. Spectrom. 1991 6 199. Davies J. and Snook R. D. J. Anal. At. Spectrom. 1986 1 195. Goudzwaard M. P. and de Loos-Vollebregt M. T. C. Spectrochim. Acta Part B 1990 45 887. Antanavicius R. Serapinas P. and Simkus P. J. Phys. D Appl. Phys. 1989 22 254. Eckert H. U. Spectrochim. Acta Part B 1985 40 145. 21 22 23 24 25 26 27 28 29 30 31 Weir D. G. J. and Blades M. W. Spectrochim. Acta Part B 1994 49 1231. Weir D. G. J. and Blades M. W. Spectrochim. Acta Part B 1990 45 615. Maessen F. J. M. J. Kreuning G. and Balke J. Spectrochim. Acta B 1986 41 3. Maessen F. J. M. J. and Kreuning G. Spectrochim. Acta Part B 1989. 44 387. Anderson H. Kaiser H. and Meddings B. in Proceedings of the Winter Confererence on Plasma Chemistry Sun Juan 1980 Heyden London 1981 p. 251. Longmire E. K. and Eaton J. K. J. Fluid Mech. 1992 236 217. Prandtl L. Essentials of Fluid Dynamics Blackie London 1952. Becker H. A. and Massaro T. A. J. Fluid Mech. 1968 31 435. Subbarao E. R. and Cantwell B. J. J. Fluid Mech. 245 245 69. Chen L. D. Goss L. P. Lynn W. F. and Roquemore W. M. The Structure of Jet Diffusion Flames eds. Chen L. D. Goss L. P. Lynn W. F. and Roquemore W. M. Springer-Verlag; Berlin 1987 Vol. 40. Dahm W. J. A. Frieller C. E. and Tryggvason G. J. Fluid Mech. 1992 241 371. Paper 6/02954J Received April 26 1996 Accepted July 23 2996 101 8 Journal of Analytical Atomic Spectrometry November 1996 Vol. 11

ISSN:0267-9477    

DOI:10.1039/JA9961101011

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

Mechanism of Peak Drift of a Grating Monochromator and a Designed Sequential Inductively Coupled Plasma Spectrometer With an Intelligent Wavelength Calibrating Device Journal of Analytical Atomic Spectrometry KELING LIU HAIBIN TAN ZHUO HUANG AND M A 0 HUANG Institute of Chemical Metallurgy Academia Sinica Beijing 10008(/. China The mechanism of the peak drift of exit spectral lines of a grating monochromator was studied experimentally and theoretically. The results indicate that the peak drift is due not only to temperature change but also to wavelength change and systematic errors. Equations describing the non-linear functional relationship between peak drift wavelength and temperature were obtained. Based on these equations a computer wavelength-calibrating program was developed and an intelligent wavelength-calibrating device was designed for use with a sequential ICP spectrometer instead of the conventional local thermostat or the real-time line-profile method.The sequential ICP spectrometer with the intelligent wavelength-calibrating device (designated the ICP-IWC ) was used to analyse various standards. The analytical results were in good agreement with the certified values and the RSDs of the determinations were about 1%. Compared with the use of the conventional local thermostat or the line-profile method the ICP-IWC has been shown to be effective; the IWC device is easy to construct and should find wide application. Keywords Monochromator; sequential inductively coupled plasma spectrometer; wavelength calibration It is well known that peak drift of exit spectral lines is a serious problem with sequential ICP spectrometers.For example if the local thermostat of a sequential ICP is not powered and the wavelengths of the analytical spectral lines A are input to the parameter data file of the sequential ICP it will be found that the exit peak positions of the lines are actually at A1 positions. 6A=Al-2 is called the peak drift and Al values are called the calibrated wavelengths of lines A. The values of 61 are of the order of 10-'nm. The mechanism of the peak drift of a grating monochromator is complicated. Temperature change is one important factor; hence in order to eliminate the peak drift almost all commercial ICP spectrometers are equipped with a local thermostat; such a device has been used for almost 100 years.Any type of local thermostat needs a long pre-heating time (usually 8-10 h) which makes the con- figuration of the ICP spectrometer complicated and the main- tenance inconvenient. For a sequential ICP spectrometer without a local thermostat each analytical spectral line has to be profiled to obtain the peak intensities. The line-profile method increases the determination time 10-20-fold because it usually requires the measurement of 10-20 points to establish the real-time peak intensity instead of a single point measure- ment at the peak position by the sequential ICP with a local thermostat. Many experiments indicate that for a sequential ICP without a local thermostat the longer the determination time the poorer the determination precision. In this work the mechanism of peak drift was studied both experimentally and the~retically.'-~ The results indicated that the occurrence of peak drift could be attributed not only to temperature change but also to wavelength change and systematic errors of the grating monochromator.The functional relationships between peak drift wavelength and temperature were determined. Based on these functional relationship equations a computer wave- length-calibrating program was developed and an intelligent wavelength calibrating (IWC) device for a sequential ICP was designed as an alternative to the traditional local thermostat or the line-profile method. The sequential ICP-IWC has been used to analyse blast-furnace slags chromite samples and various other samples for more than 2 years without the need for either long pre-heating times or profiles for each analytical line.The analytical results are in good agreement with the certified values of the standards. The RSDs of the determi- nations are about 1 YO. MECHANISM OF PEAK DRIFT OF EXIT SPECTRAL LINES OF A GRATING MONOCHROMATOR Experimental Determination of the Peak Drift An investigation of the mechanism of the peak drift of a grating monochromator indicated that the peak drift changes with both wavelength and temperature non-linearly. For example if one adjusts the alignment of the optics so that the exit peak positions of the spectral lines are in good agreement with their standard wavelengths according to the wavelength reading of the monochromator at the short wavelength side (25200 nm) then at the long wavelength side ( ~ 8 5 0 nm) one finds that all the exit peak positions of long wavelength spectral lines are different from their standard wavelengths even though the local thermostat of the sequential ICP has been pre-heated for a sufficient time.The differences could be of the order of 10-2-10-'nm depending on the quality of the ICP spec- trometer and these differences substantially decrease the detecting sensitivity of sequential ICP spectrometers. As another example if one adjusts the alignment of the optics so that the exit peak position of the Hg 435.8 nm line is in good agreement with its standard wavelength according to the wavelength reading of the monochromator at room tempera- ture (19"C) then one finds that the exit peak position of the line is different from its standard wavelength if the room temperature changes to say 29°C.The difference is about 0.7 A (cf. Fig. 2). The functional relationship between the peak drift 6;1 and wavelength A at a constant room temperature of 23.1 "C for a Spex 1702/04 monochromator is shown in Fig. 1 and that between the peak drift 62 of the Hg 435.8 nm line and temperature T for the same monochromator is shown in Fig. 2. These two functional relationships can be expressed by the following two polynomial equations 6A=1.454-(3.111 x 10-4)A+(1.079~ 10-8)A2 (1) (2) 61 = - 7.518 + 0.572'~-0.01 T2 Journal of Analjitical Atomic Spectrometry November 1996 Vol. 11 (I 01 9-1 022) 101 9I I 2000 3000 4000 5000 6000 7000 8000 ' * 0 ° * 0.80 0.60 4 0.40 2 2 0.20 2 0.00 -0.20 -0.40 Fig.1 at 23.1 "C Functional relationship between peak drift and wavelength 19 21 23 25 27 29 0.80 0.60 1 0*0° I 31 33 -0.20 19 21 23 25 27 29 31 33 TemperatureIOC Fig. 2 Functional relationship between peak drift and temperature for Hg at 435.8 nm Theoretical Calculation of the Peak Drift Based on the grating equation and the linear expansion equation of a solid the peak drift of the Hg 435.8 nm line caused by temperature change can be calculated theoretically. The grating equation of the Spex 1702/04 monochromator is as follows mA=dx(sin a+sinp) (3) where m is the order of the spectrum A the wavelength d the grating spacing o! the angle of incidence and p the angle of diffraction. For convenience the above grating equation may be expressed as follows A = (2d/m) x cos 4 x sin(4 + p) ( 4 ) where 4 is equal to 6" 51' 30".The peak drift 62 caused by a small change in the grating spacing 6d can then be expressed as follows 61 = (26d/m) x cos # x sin(# + p) ( 5 ) l t = & ( 1 + A x T + B x T 2 ) (6) The linear expansion equation of a solid is as follows and 6 d = I t 2 - l t l where A and B are linear expansion coefficients and are equal to 2.19 x and 1 . 2 ~ l o - * respectively. I and lo are the linear lengths of the solid at a given temperature t and at O"C respectively. BasFd on eqns. (5) and (6) the calculated peak drift 62 is 0.52 A when the room temperature changes from 19 to 29°C; this is less than the above-determined value possibly because the small change in the diffraction angle p has been neglected.Hence the experimentally determined functional relationships are actually used in the wavelength-calibrating program. Fig. 3 Block diagram of the sequential ICP-IWC spectrometer DESIGNED SEQUENTIAL ICP WITH AN IWC DEVICE* A block diagram of the sequential ICP-IWC spectrometer is shown in Fig. 3. The IWC device of the sequential ICP consists of the wavelength-calibrating program and a computer- automated temperature-signal collecting system which is com- posed of a temperature sensor a digital thermometer an A/D converter and an interface. The other part of the block diagram is the same as for a commercial sequential ICP spectrometer. The real-time temperature of the monochromator cabinet T is input to the computer constantly.According to the real- time temperature T and the wavelengths of the analytical spectral lines A input by the operator the calibrated wave- lengths A1 of the lines can be calculated by the wavelength- calibrating program rapidly; these are then input to the grating driver of the sequential ICP-IWC and the control system of the sequential ICP will modify the rotation of the grating so that all the peak positions of the analytical lines accurately pass the exit slit of the ICP-IWC sequentially. In order to test the capability of the IWC device the sequential ICP-IWC spectrometer was used to determine seven elements in blast- furnace slags and six elements in chromite ore^.^.^ The exper- imental conditions are shown in Table 1. RESULTS AND DISCUSSION Comparison Between Profiled Peaks and Calibrated Wavelengths Obtained with the ICP-IWC In order to test the capability of the sequential ICP-IWC spectrometer the calibrated wavelengths of seven analytical spectral lines obtained with the ICP-IWC were compared with their real-time profiled peak positions.The results are shown in Table 2 where A are the standard wavelengths of the seven analytical spectral lines A are the real-time profiled peaks and R1 are the real-time calibrated wavelengths obtained with the sequential ICP-IWC; A -Alp represents the differences between the calibrated wavelengths and the profiled peaks. It can be seen that the differences are less than 0.005 nm i.e. one scanning step which indicates that the calibrated wavelengths obtained with the sequential ICP-IWC are in good agreement with the real-time profiled peaks; hence it is possible to use the IWC device instead of the local thermostat of the sequential ICP and the line-profile method.A-& represents the differ- ences between the standard wavelengths and their real-time profiled peaks which indicates that the magnitude of the peak drift is such that the elemental components of samples cannot be determined accurately unless a local thermostat or the line- profile method or the IWC device of the sequential ICP is used. * The IWC device is the subject of a patent application. 1020 Journal of Analytical Atomic Spectrometry November 1996 Vol. 11Table 1 Experiment conditions Monochroma tor Type. Grating Observation height Entrance slit Exit slit Height of slit Scanning step Integration time Rf generator Type Power Frequency Coolant gas flow rate Auxiliary gas flow rate Aerosol gas flow rate Pressure of aerosol gas Sample uptake rate Spex 1702/04 1200 grooves mm - 13 mm 20 pm 40 pm 2 mm 0.004 nm 2 s HFS-5000D 0.95 kW 27.12 MHz 13 1 min-' 0 1 min-' 11 min-' 0.14 MPa 1.6 ml min-' Data collection and treatment Photomultiplier Negative high voltage Kinetic linear range Computer CPU Precision of thermometer Analytical spectral lines (nm) Si Ca Mg Mn Fe Ti A1 Cr R456 -5oov 1 o6 Super PC/XT 0.2"C FS 25 1.6 317.9 280.3 257.6 259.9 334.9 396.2 267.7 Table 2 Comparison between the calibrated wavelengths and the profiled wavelengths Element Cr Fe Si Mn Ca Ti Mg Wavelength 267.7 16 280.2695 259.9396 251.61 11 257.6104 3 17.933 334.9035 (A )/nm Profiled peak 267.875 280.425 260.105 25 1.760 257.775 3 18.090 335.075 (&p)/nm Calibrated wavelength (A,)/nm 267.875 280.427 260.108 251.763 257.777 3 18.088 3 3 5.074 1 1 -Alp/ nm 0 0.002 0.003 0.003 0.002 0.002 - 0.00 1 1 -Alp/ nm - 0.1590 -0.1705 -0.1654 -0.1489 - 0.1646 - 0.1568 - 0.17 15 Table3 Comparison of the analytical results for the blast-furnace slag obtained by the line-profile method and the ICP-IWC with the certified values SiO CaO MgO MnO Fe TiO ( O h ) (Yo) (Oh) (%I (%) (%) (Yo) Found values* 37.7 44.7 3.6 0.28 0.26 0.3 1 11.6 Found valuest 37.7 44.1 3.5 0.28 0.26 0.3 1 11.4 Certified values1 37.8 45.5 3.5 0.29 0.21 0.31 11.0 RSD (Yo) 0.4 0.8 0.7 0.2 0.1 0.2 0.8 *Elemental concentrations of the BH0124-4 blast-furnace slag standard determined by the sequential ICP-IWC spectrometer.?Elemental concentrations of the BHO124-4 blast-furnace slag standard determined by the line-profile method. $Certified values of the BHO124-4 blast-furnace slag standard manufactured by the Anshan Institute of Steel and Iron Ministry of Metallurgical Industry of China. Analytical Results for the Samples Obtained with the Sequential ICP-IWC Spectrometer The blast-furnace slags and the chromite ores were analysed by both the sequential ICP-IWC and the real-time line-profile method. A comparison of the analytical results obtained by the sequential ICP-IWC and the line-profile method with the certified values of the standards is given in Tables 3 and 4. In general the determined elemental concentrations of bGth the blast-furnace slags and the chromite ores are in good agreement with the certified values. The deviations are within the tolerance range of the sample analysis.CONCLUSIONS (1) An experimental and theoretical investigation of the peak drift mechanism has indicated that the peak drift of the exit spectral lines of a grating monochromator is due to temperature change wavelength change and systematic errors. (2) A non-linear functional relationship between the peak drift and wavelength was found and expressed as a polynomial equation. The longer the wavelength the smaller the peak drift. ( 3 ) A non-linear functional relationship between the peak drift and temperature was also found and again expressed as Table 4 Comparison of the analytical results for the chromite ore standard obtained by the line-profile method and the ICP-IWC with the certified values Cr,03 SiO Al,03 Fe MnO MgO Found values* 44.0 9.8 8.0 9.5 0.15 21.9 Found values? 43.9 9.8 8.3 9.5 0.15 21.9 Certified values1 44.4 9.3 7.9 9.8 0.15 21.9 RSD ( O h ) 1.4 0.9 0.2 0.7 0.9 0.3 ( O h ) (%) ( O h ) (Yo) ( O h ) (%) *Elemental concentrations of the 6855 chromite ore standard deter- mined by the sequential ICP-IWC spectrometer.?Elemental concentrations of the 6855 chromite ore standard deter- mined by the line-profile method. $Certified values of the 6855 chromite ore standard manufactured by the Anshan Institute of Steel and Iron Ministry of Metallurgical Industry of China. a polynomial equation. The higher the temperature the larger the peak drift.(4) Based on the functional relationship equations of a grating monochromator an IWC device for a sequential ICP was designed. The calibrated wavelengths obtained with the ICP-IWC are in good agreement with the real-time profiled Jouninl of Analytical Atomic Spectrometry November 1996 Vol. 11 1021wavelengths which indicates that the IWC device can be used instead of the local thermostat of the sequential ICP or the line-profile method. (5) The analytical results of the determination of several elements in both blast-furnace slags and chromite ores obtained with the sequential ICP-IWC are in good agreement with the certified values of the standards. The RSDs of the determi- nations are about 1%. (6) The IWC device makes the configuration of the ICP much simpler because of the removal of the local thermostat and the optical alignment of the ICP spectrometer much easier to recalibrate. (7 j The sequential ICP-IWC spectrometer is efficient and inexpensive to run in that no pre-heating time is necessary nor is it necessary to obtain the line-profile of every analytical line.(8) The IWC device should find wide application because it can be used not only with a sequential ICP spectrometer but also with other instruments containing a grating monochromator. This project was supported by the special fund for renewing equipment of Chinese Academic Sinica. The authors thank the Academician of Academia Sinica of China Benli Huang for his helpful comments and Dayun Zhou and Zhou Lu for their assistance. REFERENCES Liu K. Zhou D. and Tan H. presented at the 5th Beijing Conference and Exhibition on Instrumental Analysis Beijing China 1993 paper C35. Liu K. Huang Z. Tan H. et al. presented at the 2nd Changchun International Symposium on Analytical Chemistry Changchun China 1994 paper A10. Liu K. and Tan H. presented at the 6th Beijing Conference and Exhibition on Instrumental Analysis Beijing China 1995 paper C27. Liu K. and Tan H. presented at the 2nd International Symposium of Worldwide Chinese Scholars on Analytical Chemistry Shenzhen China 1995 paper F11. Liu K. Tan H. Zhou D. and Miao D. Guangpuxue Yu Guangpu Fenxi 1996 16 85. Liu K. Tan H. and Huang Z. Fenxi Huaxue 1996 24 373. Paper 6/02363K Received April 4 1996 Accepted August 20 1996 1022 Journal of Analytical Atomic Spectrometry November 1996 Vol. 11

ISSN:0267-9477    

DOI:10.1039/JA9961101019

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

Speciation of Inorganic Selenium by Inductively Coupled Plasma Mass Spectrometry with Hydraulic High Pressure Nebulization* NORBERT JAKUBOWSKI CHRISTOPH THOMAS AND DIETMAR STUEWER Institut fur Spektrochemie und angewandte Spektroskopie Postfach 10 13 52 0-4401 3 Dortmund Germany IRIS DETTLAFFf AND JUERGEN SCHRAM Fachhochschule Niederrhein Fachbereich Chemie Frankenring 20 0-47798 Krefeld Germany The speciation of SeIV and SeV' was studied by using hydraulic high pressure nebulization for sample introduction in inductively coupled plasma mass spectrometry. Ion-pair chromatography with a reversed-phase column was applied using tetrabutylammonium acetate as reagent and a methanol- water mixture as eluent. Operational conditions were carefully optimized. With a 200 p1 sample loop for injection detection limits of 0.14 pg 1-' were realized whereas with an injection volume of 2 ml detection limits could be improved to 16 ng I-'. Application of the method is demonstrated by the analysis of a tap water sample. Keywords Speciation; selenium; ion-pair chromatography; inductively coupled plasma; mass spectrometry; hydraulic high pressure nebulization For trace analysis of toxic elements it is not only necessary to determine the total content of the element in question at lower and lower levels but also to elucidate the binding state in order to evaluate the ecotoxicity and to follow the pathways of these elements in the environment and their metabolism in biological systems. Speciation of toxic as well as essential elements is therefore of increasing interest.Selenium is widely distributed in the environment but its natural geogenic concentration level is normally below 1 pg 1-' in natural waters or below 1 mg kg-I in rocks and soils provided that anthropogenic influences are only moderate. ' q 2 Four oxidation states of Se have been identified in the environ- ment in body fluids and in tissues zerovalent (Se') cationic (Se6+ and Se4+) and anionic (Se2-) species. In solution cationic Se occurs mainly as 0x0 acid anions i.e. selenate (Se042-) and selenite (Se032-) while anionic Se occurs as inorganic selenides in the human body and in sediments. The behaviour of Se in biological systems is ambivalent. It is known to be essential for plants animals and man. On the other hand deficiency can produce disease as is evident from areas with low geogenic Se level^,^ whereas it is toxic at higher levels.The fact that there is only a small concentration gap between deficiency and excess additionally complicated by dependence on the species form,4 emphasizes the need for the accurate determination of Se with respect to its species. On the other hand Se is of interest because it can reduce the toxicity of heavy metals such as Hg by the formation of SeHg but this depends strongly on the species form itself and thus on the source from which it is taken5 More recently a further area of application of Se has been in medical science in the ~ ~ ~~ ~~ ~~~ ~ * Presented in part at the 1996 Winter Conference on Plasma 1- Present address Fa. Knauer GmbH Hegauer Weg 38 14163 Spectrochemistry Fort Lauderdale FL USA January 8-13 1996.Berlin Germany. Journal of Analytical Atomic Spectrometry treatment of cancer and heart di~ease.~.' Therefore the determi- nation of inorganic Se and particularly of its species is of considerable interest for drinking water food and other systems of biological relevance.8 To date there has been a lack of reliable SRMs and CRMs for the quality assurance of Se species analysis; however recently the Measurement and Testing Programme has started a project to create a CRM in synthetic aqueous solution^.^ It should also be noted that the metabolism of inorganic Se species and the transformation to organometallic compounds and their detection in biological systems is an active area of research and has been reviewed by several workers.1°-12 The speciation of Se has a long analytical t r a d i t i ~ n .~ . ' ~ . ' ~ For separation of the different inorganic and organic species chromatographic techniques particularly LC,15 GC,16-18 gel- permeation chromatography" and HPLC,'5*20-22 have been applied in combination with different detectors among which detection by microwave-induced plasma (MIP) or ICP-AES has been favoured partially in combination with hydride generation techniques. In most instances the detection limits were not sufficiently low to determine both species at trace levels in complex matrices. However an improvement in detection limits was expected by the introduction of MS. It has been shown in recent work that ICP-MS can be a powerful detection technique for speciation analysis in combi- nation with LC HPLC and GC.23-25 ICP-MS is not only a very selective but also a very sensitive detection technique with true multi-element capability.The speciation of inorganic Se and partially of organometallic Se compounds has been investi- gated by coupling ICP-MS with LC and HPLC in combination with pneumatic nebulization,26 direct injection nebulization ( DIN),27-29 ultrasonic nebulization ( USN)30 and hydride generation.jl In previous work we have applied hydraulic high pressure nebulization ( HHPN)32 as a highly efficient nebulization tech- nique in combination with HPLC for the speciation of Cr"' and CrV1 by application of ion-pair chr~matography.~~ Detection limits at sub-pg 1 -' levels were realized for both species in drinking and mineral water samples and the pro- cedure was also applied to the analysis of waste water samples from the galvanization industry34 and of contaminated soil samples.35 As an initial part of a research programme for the speciation of organometallic Se compounds we have performed a feasibil- ity study by adapting the previously developed procedure to the speciation of Se" and SeV1.Accordingly ion-pair chroma- tography was used in combination with a reversed-phase column and methanol as the eluent. The procedure was optimized with respect to Se speciation and the problem of chromatographic interferences and of spectral interferences resulting from organic solvents was considered in detail. Journal of Anal.vtical Atomic Spectrometry November 1996 Vol.11 ( 1 023-1 029) 1023An essential prerequisite for this work was the use of HHPN as a highly efficient sample introduction technique. In previous work we have shown that an improvement in the sensitivity by up to a factor of about 10 in comparison with conventional pneumatic nebulization can be realized for several elements using continuous-flow condition^.^^ A further aim of this work was therefore to verify whether this improvement can also be realized in a chromatographic environment for an element such as Se which has a high first ionization potential (9.7 eV) and for which strong desolvation losses had been observed in an earlier in~estigation.~~ EXPERIMENTAL Table 1 Summary of operating conditions Chromatographic system Column C Eurospher RP 100-5 Concentration of ion-pair reagent 0.01 mol 1- Concentration of the methanol in eluent 40% Eluent flow rate 1 ml min-l HH PN system Sample uptake rate Sample loop volume Pressure Nozzle diameter Desolvation system Heating temperature Cooling temperature 1.0 ml min-' 0.2 ml 13.0 MPa 15 pm 120 "C 1st stage + 1 "C Instrumentation 2nd stage - 20 "C The experimental arrangement was similar to that used in previous work for the speciation of Cr.33 Therefore only the modifications made to the system are mentioned here.In the lay-out of the system a dual piston HPLC pump (Knauer Berlin Germany) with an inert Ti pumping head was used. The chromatographic column (Knauer) was a low-cost guard column (60 x 4 mm id) filled with C,,-Eurospher 10 nm material with a particle diameter of 5 pm.A commercial HHPN unit (Knauer) including desolvation with two-stage cooling was used for sample introduction. The high pressure necessary for nebulization is generated by the HPLC pump of the chromatographic system. With respect to this function the nebulizer is an integral part of the HPLC system with the additional benefit that the sensitivity is improved in comparison with a conventional pneumatic nebul- izer. The main component of the nebulizer is a nozzle plate made of a Pt-Ir alloy with an aperture of 15 pm. A carrier solution usually doubly distilled water is used to transport the liquid sample to the nebulizer where it is forced through this aperture with a pressure of up to several hundred bar and the emerging stream of large droplets is converted by an impact bead into an aerosol containing droplets with very small diameters.A filter (Ti sieve 3 pm) placed in front of the nozzle serves to protect it from becoming clogged by particles. The samples to be analysed are injected from a sample loop via an injection valve into the carrier. A selection of sample loops with volumes from 20 pl to 5 ml is available. For the initial optimization experiments a volume of 200 pl was chosen as a compromise with respect to intensity and time needs. The ground plate carrying the nozzle holder also provides the entry for introduction of the aerosol carrier gas. In contrast to earlier work oxygen was added to the aerosol carrier gas directly in front of the nebulizer. A peristaltic pump is attached to pump off the liquid waste from the spray chamber and the cooling unit of the desolvation system. A more detailed description of the whole arrangement is given elsewhere.33 The ICP-MS system used was a VG PlasmaQuad 2 TurboPlus (Fisons Instruments/VG Elemental Winsford Cheshire UK).Standard operating parameters as compiled in Table 1 were used throughout this work unless stated other- wise. For comparison with pneumatic nebulization a Meinhard nebulizer (Type C Meinhard Santa Ana CA USA) with a cooled Scott-type spray chamber was also used. The sample uptake rate was adjusted to 1 ml min-l by a peristaltic pump (Minipuls 3 Gilson Villiers-le-Bel France). Solutions In speciation studies it is important not only to avoid losses by desorption or adsorption but also to consider the possibility of conversion between the species concerned.Bearing in mind the recommendations for Se given in the l i t e r a t ~ r e ~ ~ prep- ICP-MS system Power Reflected power Nebulizer gas flow rate Auxiliary gas flow rate Coolant gas flow rate Oxygen flow rate Sampling distance Data acquisition system Dwell time per data point Total acquisition time 1500 W 40 W 0.75 1 min-' 0.5 1 min-' 15 1 min-' 0.05 1 min-' 10 mm 327.68 ms ~ 3 0 0 s Stock solutions (1000 mg 1-l) of Se" and SeV' were prepared by dissolving Na2Se0 and Na,SeO (Alfa products Johnson Matthey Karlsruhe Germany) respectively in doubly distilled water; the solutions were stabilized by the addition of HNO (Suprapur Merck Darmstadt Germany) to give a pH of 1.5. The dilutions necessary for preparation of analytical samples were always performed on the day of the analysis in order to avoid conversion of the species.From among the ion-pair reagents based on ammonium salts,38 tetrabutylammonium acetate (TBAA) (Fluka Chemie Neu-Ulm Germany) was chosen based on the results of previous It was used to retain both species Se" and SeV1 on the reversed-phase column. A stock solution of 0.1 moll-' TBAA was prepared by dissolution of the solid reagent in doubly distilled water. This was used to add the ion-pair reagent to the sample; the pH was adjusted to 3.0-3.3 by the addition of acetic acid. In this pH range selenate will exist in solution as the Se042- ion whereas selenite will be present as the hydrogenselenite ion HSe03-. A more detailed discussion of the equilibrium of these species can be found elsewhere.38 Both negatively charged ions can form anionic ion pairs which are retained on the column.In addition ammonium acetate (Merck) was added at a concentration of 1 x mol 1-1 in order to enhance ion-pair formation. A mixture of methanol (Fluka Chemie) at a concen- tration of 40% v/v in doubly distilled water ammonium acetate (1 x moll-') and TBAA added to a concentration of 0.01 moll-' was used as the eluent. The pH of both the standards and samples was adjusted to 3.0-3.3 by the addition of acetic acid. For the optimization experiments with the chromatographic system a concentration of 100 pg I-' was chosen for both Se species. Blank samples which were always measured together with analytical samples were prepared from doubly distilled water For optimization of the lens settings a standard solution containing 20 pg 1-1 In and 40% methanol was used as a tuning solution and was injected from a 5 ml sample loop.IJnless stated otherwise the eluent was continuously pumped through the system at a flow rate of 1 ml min-l. Mass Spectra and Chromatograms aration and handling of analyte solutions was performed as follows. Owing to spectral interferences from the dimer of Ar with its different isotopes the most abundant Se isotope at mass 80 is 1024 Journul of Analytical Atomic Spectrometry November 1996 Vol. 11strongly obscured and could not be used for evaluation. The contribution of this spectral interference to the isotope YSe is a factor of 200 higher in comparison with 77Se and a factor of 5 higher in comparison with 78Se; 82Se is isobarically interfered with 82Kr which is present as a contaminant in the liquid Ar supply; 74Se suffers no interference but was not used for evaluation because of its low abundance of only 0.87%.Therefore ion monitoring profiles were recorded for m 'z = 77 and 78 using the peak-jumping mode with a dwell time of 327.68 ms per data point and a total scan time of about 300 s. For quantitative evaluation of the chromatograms the peak area was always calculated using a table calculation software package with background correction. Blank values were calcu- lated from the measurements of blank solutions over the time interval of the elution. RESULTS AND DISCUSSION Initially the speciation procedure was elaborated by careful optimization of the relevant operating conditions for ICP-MS as well as for the chromatographic system. This optimization was performed with respect to maximum ion intensities lowest background and satisfactory chromatographic resolution.Throughout this part of the work HHPN was used exclusively for sample introduction into the ICP. After elaboration of the procedure a comparison with conventional pneumatic nebuliz- ation was performed operating the chromatographic system with these optimized conditions. Finally some aspects of the analytical performance are considered including analytical figures of merit and a preliminary application example. Optimization of the Procedure Oxygen gasjiow The presence of an organic solvent which is necessary for separation in the applied reversed-phase system is a severe impediment in relation to normal ICP-MS operation.Spectral as well as non-spectral interferences may arise and the latter can lead to significant losses of sensitivity for many elements. Additionally clogging of the sampler and skimmer orifices may occur at higher concentrations of organic solvents. Such disturbances can be reduced at least partially by the addition of oxygen to the aerosol gas. Therefore the first step of our optimization efforts was to measure the ion yield for both Se species as a function of the added oxygen gas flow wirh pre- selected chromatographic conditions; a sample solution con- taining 100 pg I-' of both species was injected. A mixture of 40% methanol and 0.01 moll-' TBAA was chosen as the eluent for these measurements.The results are presented in Fig. 1. 7000000 1 6000000 5 5000000 + .- $ 4000000 3000000 v a j$ 2000000 a 1000000 a n l 20 30 40 50 60 70 80 90 100 110 o2-flow rate/ml min-' Fig. 1 Optimization of the chromatographic signal intensity with varying oxygen addition; 1 selenite at 77 u 2 selenate ;It 77 u 3 selenite at 78 u 4 selenate at 78 u For the oxygen gas flow there is a lower limit of 30 ml min-' because below this value carbon deposition is observed indicat- ing that the flow is not sufficient for oxidation of the imported organic material. Above this value a rapid increase in the ion yield followed by a decrease is observed which can be ascribed to changes in the plasma generation because simultaneously the reflected power of the ICP generator increases strongly.Finally operation of the ICP generator comes close to a safety switch off. Maximum intensity is observed for an oxygen flow of 50 ml min-'. The intensity ratio for the two isotopes studied reflects their abundance hence 78Se might be preferred; how- ever considering also the background level (not shown) the less abundant 77Se isotope is preferable owing to its higher signal-to-background ratio. Ion-pair reagent For optimization of the chromatographic working conditions the influence of the ion-pair reagent was studied by adding it to both the eluent and the sample. For the eluent a concen- tration of 0.005 moll-' had been recommended in the litera- t ~ r e . ~ ~ The influence of the TBAA concentration in the range 0-0.05 moll-' in the eluent with a fixed concentration of 0.005 moll-' for the sample was investigated.The resulting chroma- tograms are shown in Fig. 2 for four different values of the TBAA concentration. Selenite is eluted prior to selenate with a minimum delay of 40 s after injection of the sample. As can be seen from Fig. 2 the concentration of the ion- pair reagent in the eluent has a significant influence on both the retention time of the species and the signal intensity. With increasing concentration the resolution of the two species is improved owing to the increasing number of exchangeable groups present on the stationary phase. At a concentration of 0.01 moll-' TBAA in the eluent the separation of the signals is satisfactory as is the intensity. Further increase in the concentration leads to deterioration of both the intensity and the resolution of the peaks because the excess of undissociated molecules of the ion-pair reagent blocks the surface of the stationary phase leading to a decrease in the number of active centres.For the separation of larger amounts of sample material it was recommended that the reagent be added to the sample so that ion-pair formation occurs before injection onto the column. Therefore variation of the TBAA concentration in the sample was also studied for optimization purposes. The range studied was 0-0.01 moll-'; the measurements were performed with the optimum concentration of 0.01 mol I-' TBAA in the eluent. No significant influence on the retention was observed; only a small influence on the intensity was apparent; hence a concentration of 0.005 moll-' TBAA was added to the sample.80000 I r 'm 60000 v) c 2 +- 8 40000 .- 25 v) c c 22 20000 - 0' 100 260 360 400 ! Time/s Fig. 2 Optimization of the TBAA concentration in the eluent with a fixed concentration of 0.005 mol I-' TBAA in the sample; 1 no TBAA 2 0.005 3 0.01 4 0.05 moll-' TBAA Journal of Analytical Atomic Spectrometry November 1996 Vol. 1 1 10257 160000- 1. :I Fig. 3 Optimization of the methanol concentration in the eluent; 1 30 2 35 3 40 4 45% Methanol Concentration The content of methanol in the eluent has a strong influence on the retention of both Se species as can be seen from the measurements presented in Fig. 3. Four methanol concen- trations were chosen ranging from 30 to 45%.A flushing period of 30 min with doubly distilled water was inserted before measurement with a new eluent concentration. After flushing the standard solutions were injected three times. From the measurements it can be seen that the retention time decreases with increasing methanol concentration for both species so that the separation of the signals deteriorates considerably whereas the influence on the signal intensity is minimal. A higher concentration of the organic solvent leads to a decrease in the'active centres by adsorption and also decreases the polarity of the eluent so that greater solubility is achieved for the non-polar ion pairs leading to faster elution. For further application a value of 40% v/v methanol was chosen in order to realize fast separation with sufficient chrom- atographic resolution and the highest possible signal intensity.Even with identical concentrations of both species the peak heights differ significantly because of their retention conditions. Selenite is always eluted first resulting in a very intense and sharp peak whereas the selenate peak is eluted last with a significantly lower peak height due to peak broadening. For data evaluation peak heights would result in differing sensi- tivities whereas peak area evaluation will lead to comparable sensitivities; therefore peak areas were chosen for evaluation of the chromatographic signals. EluentJEow rate One of the advantages of HHPN is that the flow rate of the eluent can be varied over a greater range than with conven- tional pneumatic nebulization. For our system with a nozzle diameter of 15 pm the variation range is 0.5-3.0 ml min-l.The choice of eluent flow rate is a typical optimization problem because although the total analysis time can be shortened by using a higher eluent flow rate this is often at the expense of poorer peak separation and with the consequence of a higher pressure in the chromatography system. The optimization study was restricted to the interval 0.8-1.4 ml min-'; the results are presented in Fig. 4. As expected the results demonstrate that lower flow rates lead to an increase in the retention times thereby improving peak separation of the species. In general the signal intensity of both species is not influenced by HHPN whereas pneumatic nebulization usually produces a strong dependence of the signal intensity on the sample uptake rate.A flow rate of 1 ml min-' was found to be a good compro- mise with the elution of both species completed after 200s. 180000 L I - I v) g 120000 3 0 ,u 3 60000 .- a u) C c - 0 50 100 150 200 250 300 350 400 Time/s Fig.4 moll-' TBAA); 1 0.8 2 1.0 3 1.2 4 1.4 ml min-' Optimization of the eluent flow rate (40% methanol 0.01 With this flow rate the pressure in the chromatography system is 13 MPa which is considerably below the safety limit of 40 MPa for the column. Injection volume The measurements discussed above were performed in the flow-injection mode with a sample loop volume of 200 p1. Basically there is no limitation on the sample volume provided that the column is not overloaded.Therefore the influence of the sample volume on the analytical signal was investigated next. A series of measurements was performed with increasing sample loop volumes from 0.2 to 2 ml and a constant analyte concentration of 10 pg 1 - l . The resulting chromatograms are shown in Fig. 5. The peak height increases with increasing loop volume such that the peak height increases by a factor of 10 for a 2ml sample loop volume in comparison with a sample loop volume of 0.2ml. This shows that both species are concentrated on the column while neither the chromato- graphic resolution nor the peak width change significantly demonstrating that the capacity of the column is sufficient for the low concentrations in the samples under investigation. For a real sample the choice of the injection volume has of course to consider the total load of anions in the sample.Comparison of HHPN and Pneumatic Nebulization Having elaborated the procedure for speciation as far as the chromatographic part is concerned it was now possible to apply the optimized conditions for comparison of HHPN with pneumatic nebulization by a conventional Meinhard nebulizer. Samples with a concentration of 20 ng ml-' of both species were injected using a 200 pl loop. From the resulting 300000 T t 250000 v) $ 200000 C 0 2 150000 .- E 6 100000 v) c C - 50000 0 10 Time/s Fig. 5 Chromatograms at 77 u with different sample loop volumes; 1 0.2 2 0.5 3 1.0 4 2.0ml 1026 Journal of Analytical Atomic Spectrometry November 1996 Vol. 11chromatograms at mass 77 (not shown) an improvement in the peak area was observed for HHPN by a factor of 25 for selenite and 30 for selenate.This improvement factor is even higher than expected from previous experience so that desolv- ation losses if present do not play a significant role. This is in agreement with the experience that generally desolvation losses do not occur when the element in question is dissolved as a salt or is present in solution as a complex as in this case because the temperatures of the desolvation system are far too low to evaporate the solid material after de-humidification of the aerosols. According to our previous experience desol vation losses may occur for a number of non-metal elements when they are nebulized as their acids in a liquid form. Owing to the evaporation of liquids from small aerosol droplets this holds true even for HC1 which has a boiling temperature far above the usual desolvation temperatures.It should be men- tioned that on the other hand the loss of analyte material can be used analytically for on-line trace-matrix separation as has been discussed in more detail by Wildner and Wunsch.36 Concerning the high intensity gain observed for HHPN in comparison with pneumatic nebulization it should be men- tioned that in aqueous solutions an intensity gain by a factor of 11 can be realized for HHPN. This is surprising because it is comparable to improvements realized also for elements with lower ionization energies. On the other hand both nebulization techniques show strong sensitivity losses in 40% methanol which can be up to one order of magnitude and strongly depend on the oxygen flow rate.A direct comparison is not possible because of the different optimum working conditions for both nebulizers; a more detailed investigation will be carried out in future work. 180000 - 160000-r Analytical Performance Stability and recovery of species In order to check the stability of our standards and to ensure that the chosen working conditions do not give rise to changes in the oxidation states of the Se species the results of measure- ments carried out immediately after preparation of the stock standard solutions and 9 weeks after preparation were com- pared. The concentrations remained unchanged and the chro- matograms of both species did not show any contribution from the other species neither after preparation of the stock solution nor 9 weeks later; hence it could be concluded that no conversion of the species or losses had occurred at the pH of 1.5 chosen for the stock solutions.A more detailed study of the stability of Se'" and SeV' considering different container materials pH values and temperatures is presented else~here.~' The recoveries were 97% for selenite and 101% for selenate. - 5F Calibration and detection limits The repeatability of the analytical procedure was measured from ten replicate injections of 200 p1 of a standard solution containing both Se species at a concentration of 5 pg 1-l. At this concentration which is not far above the detection limit Table 2 Calibration data and limits of detection (LOD) it i ! :-I I 140000 c.5 120000 .g 100000 4 'I I 3 i ! 11 I 50 100 150 200 250 300 0 Time/s Fig. 6 Calibration chromatograms at 77 u with selenite and selenate concentrations of 1 5 2 25 3 50 4 75 5 100 pg 1-' each the RSD of the peak areas was 2.6% for selenite and 2.9% for selenate. On this basis calibration was performed with sample loop volumes of 200 pl and 2ml. With a 200 pl injection volume five repeated measurements for five standard solutions within a concentration interval of 5-1OOpgl-' and a blank solution were performed. The chromatograms for 77Se are presented in Fig. 6 and a compilation of the resulting cali- bration parameters obtained with 77Se and 78Se is presented in Table 2 together with detection limit values (3a). The calibration is linear over the concentration range studied i.e.over two orders of magnitude. The upper limit is set by the dynamic range of the secondary electron multiplier in the counting mode. Switching to the analogue mode would permit an extension of the dynamic range but this was not applied here. For the two isotopes studied the detection limits are lower by a factor of 15 for the isotope at 77u with which a value of 0.14pgl-' was realized for both Se species. The difference between the isotopes can be attributed to the high background for 78Se caused by the interference of the Ar dimer. Taking into account the different abundances of both isotopes the sensitivity is virtually identical; hence 77Se was the isotope of choice for quantitative analysis and was used for further investigations unless stated otherwise.The negative values for the y-axis intercepts indicate a certain over-compensation in background subtraction. A further series of calibration measurements was performed with a 2 ml injection volume using four standard solutions with concentrations of 0.5 1.0 1.5 and 2.0 pg 1-' of selenite and selenate which are considerably lower than those used above. The analytical procedure was repeated three times. The resulting calibration parameters are compiled in Table 2. With a comparatively high sample volume of 2 ml concentration of both species on the column leads to an improvement in the detection limits by nearly an order of magnitude for both species resulting in a value of about 20 ng l-l while the absolute detection limits (just above 36 pg) remain unchanged in comparison with an injection volume of 200 pl.The detection limits obtained are well below the maximum permissible limit Isotope used for evaluation Species Slope a ( x lo4) y-axis intercept b LOD/pg 1 - Absolute LOD/pg Sample loop volume 200 p1 77Se Se" 1.6 77Se SeV1 1.9 78Se SeJV 5.1 78Se Sev' 6.0 -11120 - 7000 153 - 9740 Sample loop volume 2 ml 7'Se SeIV I 7 S e fieV1 - 1 .o 1.2 1440 1510 0.14 0.14 2.1 2.2 0.018 0.016 28 28 420 420 36 32 Journal of Analytical Atomic Spectrometry November 1996 Vol. 11 1027of 10 pgl-' in drinking water as prescribed by the World Health Organisation ( WHO)41 and the US Environmental Protection Agency ( EPA).42 In order to assess the performance of the proposed procedure further the results were compared with those reported by other workers for the speciation of organic and inorganic Se compounds by HPLC in combination with ICP-MS.This work presents detection limits in the medium to low ng 1-' range depending on the injection volume. Quijano et a1.26 have realized detection limits of 1.6 and 1.2 pg 1-' for selenite and selenate respectively in combination with the determination of selenocystine and selenomethionine by applying pneumatic nebulization and using a 100 pl injection volume. Similar detection limits have been obtained by KOlbll4 for selenite and selenate. Other workers have reported significant improve- ments by application of high efficiency nebulizers for Se speciation. Houk e t realized absolute detection limits of 5-10 pg for both species by application of HPLC-DIN- ICP-MS; Watson and McLeod3' realized detection limits of 8 ng 1-' for Sevl by application of LC-USN-ICP-MS.In summary the detection limits realized with different high efficiency nebulizers are comparable demonstrating that HHPN can compete with other high efficiency nebulization techniques for speciation analysis by ICP-MS. Application As a preliminary application example a tap water sample was analysed by the proposed speciation procedure. This type of sample avoids the need for extensive sample preparation. The analytical determination was performed using standard additions for calibration with selenite and selenate added in incremental concentrations and a sample loop volume of 200 pl. TBAA was added at a concentration of 0.005 moll-' to the sample.The resulting solutions were analysed together with blank samples immediately after preparation. As before quantitative evaluation was restricted to the isotope 7'Se. The chromatogram obtained for the tap water sample is shown in Fig. 7. Both Se species are present with selenate predominating. This is not unexpected because the chlorine content of tap water favours this species owing to greater stability. The presence of selenite is perhaps surprising because it might have been expected that owing to the stability of Se" only SeV1 would be present in water samples at about pH 6 as investigated here.40 However selenite has also been determined previously in well waters at levels between 0.2 and 0.4 pg 1- ' .43 In our case quantitative evaluation results in concentrations of 0.26k0.07 pg 1-' for Se" and 0.46k0.05 pg 1-' for SeV' with a total of 0.72k0.09 pg 1-'.For an independent verification of this result we had no alternative speciation technique at our disposal but had to restrict ourselves to a determination of total Se by ICP-MS with a Meinhard nebulizer for sample introduction. In this instance the tap water was stabilized with 0.1 moll-' HN03 ' * 0 ° 3 b 9001 I 50 100 150 200 250 300 Timels Fig. 7 Analytical signal from speciation analysis of a tap water sample and then analysed by standard additions of 1 2 and 3 pg 1-l selenite using In at a concentration of 20 pg I-' as internal standard. A value of 0.85+0.03 pg 1-' was obtained for Se again using mass 77 for evaluation and the agreement can be considered satisfactory.Concerning the applicability of ion-pair chromatography to real samples some problems which became apparent in this work should be pointed out. The pH of the samples should be limited to the range 2-8. If the pH is too low selenite will be present in the sample as neutral H,SeO which cannot form ion pairs and will therefore be eluted in the void volume. At pH>7 OH- ions can also form ion pairs thus competing with the Se species. Additionally salt loads of more than 0.01 moll-' may give rise to chromatographic interferences as discussed in more detail by Kolbl for NaC1.38 Nevertheless ion-pair chromatography seems to be promising because it permits the determination of inorganic and also organometallic Se species such as selenocystine and selenomethionine as has been shown elsewhere.44 There is also the problem that there are no suitable CRMs or SRMs available to check the accuracy of speciation tech- niques although this is currently being addressed by the Measurement and Testing Programme.CONCLUSION The technique described here is sensitive rapid and flexible. Although it has been developed for the speciation of Se it can also be used for the determination of other elements of which at least one species forms 0x0-anions. It has been demonstrated that the technique can be used for the determination of both Se" and SeV' at trace levels in drinking water. Future work will focus on organic Se compounds in biological samples. As regards further development significant improvements may be expected from additional preconcentration new ICP-MS instrumentation and highly efficient sample introduc- tion techniques among which hydride generation or application of GC seem to be particularly promising.The work was supported financially by the Bundesministerium fur Bildung Wissenschaft Forschung und Technologie and by the Ministerium fur Wissenschaft und Forschung des Landes Nordrhein-Westfalen. REFERENCES 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Nriagu J. O. in Occurence and Distribution of Selenium ed. Ihnat M. CRC Press Boca Raton FL 1989 p. 327. McNeal J. M. and Balistrieri L. S. in Selenium in Agriculture and Environment ed. Jacobs L. W. American Society of Agronomy and Soil Science Society of America Madison WI 1989. Barclay M. N. I. and MacPherson A. J. Sci. Food Agric.1986 37 1133. Schroeder H. A. and Mitchener M. J. Nutr. 1971 101 1531. Cappon C. J. in Analysis of Contaminants in Edible Aquatic Resources ed. Kiceniuk J. W. and Ray S. VCH New York 1994. Jackson M. L. Appl. Geochem. 1986 1 175. Oldfield J. E. Bull. Selenium Tellurium Devel. Assoc. November 1993. Barclay M. N. I. and MacPherson A. Br. J. Nutr. 1992 68 261. Olivas R. M. Donard 0. F. X. Camara C. and Quevauviller P. Quim. Anal. 1995 14 136. Olivas R. M. Donard 0. F. X. Camara C. and Quevauviller P. Anal. Chim. Acta 1994 286 357. Alaejos M. S. and Romero C. D. Chem. Rev. 1.995 95 227. Kolbl G. Kalcher K. Irgolic K. J. and Magee R. J. Appl. Organomet. Chem. 1993 7,443. Robberecht H. and Van Grieken R. Talanta 1982 29 823. Kolbl G. Mar. Chem. 1995 48 185. Pitts L.Fisher A. Worsfold P. and Hill S. J. J. Anal. At. Spectrom. 1995 10 519. 1028 Journal of Analytical Atomic Spectrometry November 1996 Vol. 1 116 Uchida H. Shimoishi Y. and Tijei K. Environ. Sci. Technol. 1980 14 541. 17 Tanzer D. and Heumann K. G. Atmos. Environ. 1990,24A 3099. 18 De la Calle Guntiiias M. B. lobinski R. and Adams F. C. J. Anal. At. Spectrom. 1995 10 111. 19 Bratter P. Gercken B. Tomiak A. and Rosick U. in Trace Element Analytical Chemistry in Medicine and Biology ed. Bratter P. and Schramel P. Proc. Fifth Int. Workshop Neuherberg Germany Walter de Gruyter New York 1988 p. 119. 20 Suzuki K. T. Itoh M. and Ohmichi M. J. Chromatogr. 13 1995 666 13. 21 Laborda F. de Loos-Vollebrecht M. T. C. and de Galan L. Spectrochim. Acta Part B 1991 46 1089. 22 LaFreniere K.E. Fassel V. A. and Eckels D. E. Anal. Chem. 1987 59 879. 23 Seubert A. Fresenius’ J. Anal. Chem. 1994 350 210. 24 Hill S. J. Bloxham M. J. and Worsfold P. J. J. Anal. At. Spectrom. 1993 8 499. 25 Vela N. P. Olson L. K. and Caruso J. A. Anal. Chem. 1993 65 585A. 26 Quijano M. A. GutiCrrez A. M. PCrez-Conde M. C. and Carnara C. J. Anal. At. Spectrom. 1996 11 407. 27 Houk R. S. Shum S. C. K. and Wiederin D. R. Anar‘. Chim. Acta 1991 250 61. 28 Thompson J. T. and Houk R. S. Anal. Chem. 1986 58 2541. 29 Shum S. C. K. and Houk R. S. Anal. Chem. 1993,65,2972. 30 Watson P. and McLeod C. W. in Recent Advances in Plasma Source Mass Spectrometry ed. Holland G. BPC Wheatons Exeter 1995 p. 152. 31 32 33 34 35 36 37 38 39 40 41 42 43 44 Olivas R. M. Quetel C. R. and Donard 0. F. X. J. Anal. At. Spectrom. 1995 10 865. Jakubowski N. Feldmann I. Stuewer D. and Berndt H. Spectrochim. Acta Part B 1992 47 119. Jakubowski N. Jepkens B. Stuewer D. and Berndt H. J. Anal. At. Spectrom. 1994 9 193. Andrle C. M. Jakubowski N. and Broekaert J. A. C. Spectrochim. Acta Part B in the press. Posta J. Berndt H. Luo S.-K. and Schaldach G. Anal. Chem. 1993 65,2590. Wildner H. and Wunsch G. J. Prakt. Chem. 1995 337 542. Cheam V. and Agemian H. Anal. Chim. Acta 1980 113 237. Kolbl G. PhD Dissertation University of Graz 1994. Syty A. Christensen R. G. and Rains T. C. J. Anal. At. Spectrom. 1988 3 193. Cobo M. G. Palacios M. A. Camara C. Reis F. and Quevauviller P. Anal. Chim. Acta 1994 286 371. International Standards for Drinking Water World Health Organisation Geneva 3rd edn. 1971. Water Quality Criteria US Environmental Protection Agency Washington DC 1972. (EPA-R3-73-033). Heumann K. G. and Grosser R. Fresenius’ Z . Anal. Chem. 1989 332 880. Potin-Gautier M. Boucharat C. Astruc A. and Astruc M. Appl. Organomet. Chem. 1993 7 593. Paper 6/05 1 65 K Received July 23 1996 Accepted September 9 1996 Journal of Analytical Atomic Spectrometry November 1996 Vol. 11 1029

ISSN:0267-9477    

DOI:10.1039/JA9961101023

出版商:RSC    

年代:1996

数据来源: RSC

摘要:

Determination of Gold and Platinum in the Presence of Blood Plasma Proteins Using Inductively Coupled Plasma Mass Spectrometry With Direct Injection Nebulization* JOHN CHRISTODOULOU MINA KASHANI BERNIE M. KEOHANEt AND PETER J. SADLERS Department of Chemistry Birkbeck Collexe University of London Gordon House and Christopher Ingold Laboratories 29 Gordon Square Journal of Analytical Atomic Spectrometry - . London WClH OPP UK The effects of the blood plasma proteins albumin (67 kDa) and transferrin (80 kDa) on the determination of Au and Pt respectively by ICP-MS using direct injection nebulization (DIN) or conventional pneumatic nebulization (PN) have been investigated. Detection limits using DIN were determined to be 0.6 pg (0.03 pg 1-') and 1.6 pg (0.08 pg 1-l) for 195Pt and 197A~ in 1.0 pmol dm-3 solutions of transferrin and albumin respectively in 0.1 mol dm-3 TRIS buffer.Precisions were high cu. 0.5% over the range 1-100 pg 1-'. Calibrations were obtained with excellent linearity and there was a wide linear dynamic range of four orders of magnitude with little interference from the protein. The binding of the anti-arthritic compound triethylphosphine gold(1) chloride (Et,PAuCl ) to albumin at various Au albumin molar ratios was investigated using DIN-ICP-MS. It was concluded that DIN-ICP-MS is an improved method for determination of Au and Pt in the presence of proteins and therefore potentially valuable in pharmacological studies. Keywords Inductively coupled plasma mass spectrometry ; direct injection nebulization; gold; platinum; blood plasma proteins There is extensive interest in the use of metals in medicine.' For example Au complexes are widely used as anti-arthritic drug^,^.^ Pt ammine compounds are effective anti-cancer agents4 and there is much potential for the use of other metal compounds as drugs.Blood plasma proteins play a role in drug delivery and targeting for example transferrin can act as a carrier for delivering Pt drugs to cancer cells,5 and albumin carries 70-95% of the circulating Au in the blood of patients treated with Au anti-arthritic drugs.6 These proteins ha\.e been studied extensively for their binding properties with Pt5,' and Au.~-" The binding site on albumin for Au' drugs is known to be C y ~ 3 4 . ~ * ~ ~ Metals of interest are at low pg 1-l levels in metallo-proteins and are below the detection limits of techniques such as FAAS and ICP-AES.ETAAS has adequate sensitivity but requires optimization for each sample prior to analysis. ICP-MS is a highly sensitive multi-element technique and has been applied to the study of metall~-proteins.~~-~~ Sample dilution is neces- sary prior to analysis by ICP-MS in order to reduce total dissolved solids below 0.2% to avoid blockage of the nebulizer tip and sampling cone. Elder and co-workers have studied Au drugs and their metabolites using ICP-MS16-'9 and similar *Presented in part at the 1996 Winter Conference on Plasma Spectrochemistry Fort Lauderdale FL USA January 8-13 1996. To whom correspondence should be addressed. Present address Department of Chemistry University of Edinburgh West Mains Road Edinburgh EH9 355.investigations by various workers have been conducted on Pt Also wash-out procedures can be more time con- suming than the sample analysis particularly for elements with known memory effects such as Au owing to the large dead volume of the sample introduction Fassel and ~ o - w o r k e r s ~ ~ - ~ ~ first described a microconcentric nebulizer termed a direct injection nebulizer (DIN) placed inside the injector tube of the ICP torch eliminating the need for a spray chamber. The low dead volume offered faster sample introduction and wash-out times including memory- prone elements and reduced peak broadening in FI analysis. DIN has been coupled with various plasma source instruments including ICP-AES,28 and MIP-MS2' and Wiederin et aL3' have developed an improved DIN coupled with ICP-MS.Rinse-out times are greatly reduced for elements with memory effects and as an example Powell et aL3' have used this method for the determination of Hg. Very few investigations of metallo-protein analysis using DIN-ICP-MS have been reported32 and so far no determi- nations of Pt or Au in the presence of proteins. In the present paper the results are reported for experiments to optimize DIN-ICP-MS for the determination of Au in the presence of human serum albumin and Pt in the presence of apo human serum transferrin as part of a programme for the study of competitive binding of these and other metals with blood plasma proteins. The binding of the anti-arthritic compound triethylphosphine gold(1) chloride (Et,PAuCl) to albumin at various Au albumin molar ratios has also been investigated.EXPERIMENTAL Instrumentation The experiments were performed using a CETAC Microneb 2000 direct injection nebulizer (CETAC Technologies Omaha NE US) coupled with a VG PlasmaQuad PQ2 ICP-MS (VG Elemental Winsford Cheshire UK). The DIN consists of a microconcentric nebulizer constructed inside the injector tube of the torch and a detailed description of the instrumentation is available in the literat~re.~' The carrier liquid was transported through a capillary made from fused silica (id 60 pm x 0.4 m long) directly into the plasma thereby avoiding the need for a spray chamber. Samples were injected into the carrier stream via an injection valve con- structed from polyether ether ketone (PEEK) material to provide a metal-free system.Transport of liquid required a backpressure of 17 x lo5 Pa provided by a gas displacement pump (GDP). Optimization of the DIN-ICP-MS system was performed on a daily basis using a 500 pl sample loop to give a steady- state signal for approximately 5 min. The instrument operating Journal of Analjfical Atomic Spectrometry November 1996 Vol 11 (1031-1035) 1031conditions are listed in Table 1. The nickel cones showed no signs of erosion when water was nebulized through the direct injection nebulizer (as other workers have found3') so they were used for this work. A 20 pl sample loop gave a steady-state signal for 3-4 s and was used for all experiments. Data Acquisition Time resolved analysis (TRA) software (VG Elemental Winsford UK) was used for continuous element monitoring during analysis.Data were acquired in the peak-jumping (PJ) mode for Au and Pt individually and for each scan data were stored as a unique time slice. A 1 m/z position was selected for each element using a 0.5 s time slice 10 ms dwell time and 3 measurements per peak. All traces were exported as ASCII files into a spreadsheet program where peak areas were determined by integration of counts under each peak. Short-term stability tests of the DIN-ICP-MS system also used the PJ mode with 160 ms dwell time 3 measurements per peak and 30 s acquisition time which gave RSDs of less than 1% for 10 replicates of a 10 pg 1-1 multi-element standard. Detection limits were determined with TRA for DIN-ICP-MS otherwise PJ parameters of 10 ms dwell time and 3 measure- ments per peak were used with the standard VG software (PQVision) for conventional pneumatic nebulization (PN) in ICP-MS.The LOD was defined as the concentration of the analyte equal to 3s of the background signal. The background was taken as the blank measured by PN a peak-free region of the TRA trace for DIN with 0.1 mol dm- TRIS buffer or protein blank injections using 10 replicates for each blank. Three replicates for each sample were examined unless indicated otherwise and external Au standards were run at regular intervals to correct for signal drift during analysis of triethylphosphine gold(1) chloride ( Et,PAuCl) samples. Reagents Au and Pt standard solutions (10000 mg 1-' in 8% HC1) were supplied by Aldrich (Gillingham Dorset UK).Human serum albumin was obtained from two sources (a) Sigma (Poole Dorset UK) as fatty acid and globulin-free (HSA) and (b) Delta Biotechnology (Nottingham UK) as recombinant human albumin (rHA). Apo human serum transferrin (HTF) was obtained from Sigma. Triethylphosphine gold(1) chloride was supplied by Aldrich. Water purified by an Elga Spectrum reverse osmosis water purification system (Elga High Wycombe UK) and with resistivity >18 MR cm was used throughout this work. Standards for stability tests and detec- Table 1 Instrument operating conditions for DIN-ICP-MS ICP-MS ICP torch Argonjlow rates - Outer gas* Intermediate gas* Aerosol carrier gas* GDP-DIN parameters - DIN nebulizer gas (argon) pressure* GDP pressure* Liquid flow rate* Plasma forward power Reflected power Sampling position* ICP-MS interface - Sampler Skimmer Analyser pressure VG PlasmaQuad PQ2 CETAC B-23 14 1 min-' 0.7 1 min-l 0.15 1 min-' 5.4 x lo5 Pa 17x lo5 Pa 100 pl min-' 1350 W <10 w 10 mm from front of load coil 1.00 mm Ni cone 0.75 mm Ni cone 2 x Pa * These values were adjusted daily to maximize ion signal intensity.tion limit work were prepared in 2% v/v nitric acid (Suprapur grade Merck Lutterworth Leicestershire UK). All other standards and samples were prepared in 0.1 mol dm-3 2-amino-2-( hydroxymethyl)propane-1,3-diol hydrochloride (TRIS buffer) (Sigma) at pH 7. All plastic ware was soaked in dilute nitric acid (10% v/v) and rinsed thoroughly with water prior to use. Samples and standards were prepared and stored in Nalgene poly(methy1pentene) containers (Merck).Standards samples and buffer were freshly prepared for each set of experiments. TRIS buffer has been shown to offer good chromatographic separation of metallo-proteins without compromising ICP-MS performance.12 Preliminary experiments showed that TRIS buffer HSA rHA and HTF were free from Au and Pt. Protein standards were prepared from 10 pmol dm-3 solutions of HSA and HTF spiked with 1000 yg 1-1 of Au and Pt respectively. The molar ratio of metal to protein was 0.5 1 which is in the range normally used for binding studies.' Triethylphosphine Gold-Albumin Isolated human albumin contains less than one free SH (Cys34) per mole of albumin as a result of blocking e.g. as a mixed disulfide with cysteine.Et,PAuCl was reacted with rHA con- taining a high thiol content (ca. 0.8 SH per mole indicative of largely unblocked Cys34) to give albumin-Cys34-S- Au-PEt,. This is the complex thought to exist in the blood plasma of patients treated with the Au drug auranofin.8*'0 The Au-protein samples were prepared as follows. Aliquots of a fresh stock solution of Et,PAuCl in methanol (25 mmol dm-3) were added to a 1 mmol dm-3 solution of rHA in 0.1 mol dm- TRIS buffer at pH 7 so as to give mole ratios of Au albumin of 0.5 1 and 1 1. The reaction was complete within 1 h at ambient temperature.' Gel filtration columns (PD10 Pharmacia Uppsala Sweden) were used to separate bound and unbound Au for both ratios using TRIS buffer as the eluent. Aliquots of samples taken prior to separation for total Au measurement were diluted 2500-fold with TRIS buffer for ICP-MS measurements to give protein concentrations of 0.4 pmol dm- and Au concentrations in the region of 1-100 pg1-'.A sample volume of 2.5cm3 was introduced onto the PDlO column which was eluted with two successive 3.5 cm3 volumes of buffer for collection of high M and low M fractions respectively. Fractions from the PDlO separations were diluted appropriately to bring protein and Au concentrations close to those of the original sam- ples. Protein concentrations were determined from the absor- bance at 279 nm assuming an extinction coefficient of 0.526 mg-l ml crn-l. RESULTS AND DISCUSSION DIN Optimization Continuous .nebulization of biological materials at concen- trations ~ 0 .2 % m/v of dissolved solids is known to cause blockages of the sampling cone and nebulizer tip.34 In the work described here 20yl of sample were introduced by FI into the carrier stream to minimize the amount of protein injected. The timings of the load and inject sequences for DIN were adjusted so as to minimize peak tailing. Typical peak profiles are shown in Fig. 1 for five injections of Au. Similar profiles were obtained for Pt (data not shown). From these measure- ments it was concluded that a 10s injection time was appro- priate for all samples and the time for the signal to return to the baseline level was 10 s for Pt and 15 s for Au in TRIS buffer. Similar values were observed for Pt and Au in the presence of HTF and HSA respectively at micromolar concen- trations. The load time was extended by typically 30 s to 1032 Journal of Analytical Atomic Spectrometry November 1996 Vol.11.- 2*oo1 O ? 1.50. \ Q 5 1.00. c. t 0.50- 0 0 50 Time/s Ij 250 300 Fig. 1 standard in 0.1 mol dm-3 TRIS buffer Peak profiles for five repeat injections of a 100 pg 1-' Au obtain a steady baseline before the next injection. Longer load times (up to 80 s) were necessary for Au particularly f w the triethylphosphine gold samples owing to the observation of memory effects. Detection Limits The detection limits for Au and Pt in 2% nitric acid were determined for direct injection and conventional pneumatic nebulization. This was repeated using 0.1 mol dmP3 TRIS buffer 1 pmol dm-3 of HSA and of HTF and the results are shown in Table 2.The LODs for concentrations using DIN are comparable to those for PN for both metals but the LODs for the absolute amounts are almost two orders of magnitude lower for DIN owing to the small volume of sample injected (20 pl compared with 1 ml for PN). TRIS buffer contains salts which increase the background noise as does the presence of protein so these values are higher than in 2% nitric acid. These detection limits using PN are comparable with previous reports on A u ' ~ and Pt2' by ICP-MS using PN. This is the first report of the determination of Pt and Au using DIN. Cali bra tion DIN-ICP-MS responses for different concentrations of Au and Pt in 0.1 mol dm-3 TRIS buffer were measured and thi data are shown in Fig. 2. There is good linearity between signal response and metal concentration up to at least 100 pg 1-' the correlation coefficients being 0.99999 and 0.99998 for Au and Pt respect- ively.RSDs for Au ranged from 3.9% at 1 pgl-' to 0.4% at lOOpgl-' and for Pt from 1.0% at 1 pg1-I to 0.4% at 100 pg1-'. This is an improvement in the precision for measurements using PN that are commonly reported at 2% for concentrations that are not affected by background noise typically 50 pg l-'.'' Background noise contributed to the lower precision for analyte concentrations at the lower pg 1-' values. With high concentrations (1000 pg 1-') using DIN peak tailing was evident and excessive rinse times were necessary. Table 2 Comparison of LODs using PN and DIN Method (carrier) 195Pt DIN (nitric) 0.01 pg 1-' DIN (TRIS) 0.01 pg I-' PN (nitric) 0.04 pg 1-' 40 Pg 0.2 Pg 0.2 Pg 0.6 Pg DIN (protein-TRIS) 0.03 pg I-' 19 Au 0.16 pg I-' 160 PP 0.01 pg 1-' 0.2 pg 0.04 pg I - ' 0.8 P8 0.08 pg 1- 1.6 Pg 3.00 - 2.50 - c ; 2.00 - e .- v) 0 - 1.50 - Q F c !? c 2 1.00- 0 OSO 1 0.00 0 20 40 60 80 100 Concentration / pg I" Fig.2 Plots of concentration versus count rate for aqueous standards of Au and Pt in 0.1 mol dm-3 TRIS buffer showing the linearity of the DIN-ICP-MS responses (correlation coefficients 0.999 99 Au; 0.999 98 Pt). RSDs for Au decreased from 3.9% at 1 pg 1-' to 0.4% at 100 pg l-' and for Pt from 1% at 1 pg I-' to 0.4% at 100 pg I-' Linear Dynamic Range (LDR) The LDR was determined by injecting various samples of Pt-HTF (0.5 1 molar ratio) and Au-HSA (0.5 1 molar ratio) obtained by dilution of 10 pmol dm-3 protein-metal solutions to cover the range 0.1 nmol dm-3 - 10 pmol dm-3 of protein and O.O1-lOOOpgl-l of metal and measuring the DIN- ICP-MS response.The results of linear range studies for Au and Pt are shown in Table 3. The LDRs were four orders of magnitude which is a wide range for protein samples. Metal concentrations below 1 pg 1-' (< 10 nmol dm-3 of protein) were approaching the limit of quantitation (10 x detection limit) which is 0.3 pg 1-' for Pt and 0.8 pg I-' for Au. The upper limit could have been raised by another order but the high metal concentrations would have reduced the lifetime of the detector and long rinse times would have been required to reduce signal to background levels in particular for Au. However protein concentrations were tolerated at this level but concentrations greater than 10 pmol dmP3 tended to cause blockage of the DIN capillary (i.d.5 x mm) so it was comparable to conventional PN for tolerance of total dissolved solids (0.2%). Excellent correlation coefficients were achieved for both metals; the slopes of both lines are close to 1.0 so it can be inferred that the presence of the protein has no effect on the response to Au and only a slight effect for Pt. For all the Au-HSA measurements the precision was 2% whereas for Pt-HTF the precision varied from 3.6% (1 pg 1-' Pt) to 0.7% The influence of protein on count rate for Au and Pt concentrations in the micromolar range was investigated since competitive binding of metals with plasma proteins is of in vivo significance within this range and could also be relevant to chromatographic separations using microbore columns.The DIN-ICP-MS responses for five injections of Au and Pt (100 pg 1-') were compared with those of Au-HSA (0.5 1 molar ratio) and Pt-HTF (0.5 1 molar ratio) at the same metal concen- tration and the data are shown in Table 4. These results show that micromolar concentrations of HSA or HTF do not affect the signals for Au and Pt respectively. The combined RSDs for the Au and Pt measurements are 0.8 and 1.3% respectively (loOopg1-' Pt). Journal of Analytical Atomic Spectrometry November 1996 Vol. 1 1 1033Table 3 Element-protein m/z LDR/pg 1-l Slope of log-log plot Correlation coefficient LDR slopes and correlation coefficients for log-log plots of count rate against protein concentration for Au-HSA and Pt-HTF Pt-HTF 195 1-1000 0.8984 0.9998 Au-HSA 197 1-1000 1.0147 0.9998 and are calculated from the combination of random errors.Therefore under these conditions it is possible to use aqueous standards for the determination of Au and Pt in protein samples. Triethylphosphine Gold-Albumin The orally active anti-arthritic drug auranofin [ triethylphos- phine gold(1) tetraacetyl-P-D-thioglucose] reacts with Cys34 of human albumin to form albumin-Cys34-S-Au-PEt3 with release of tetraacetylthioglucose. This form of albumin is thought to exist in patients treated with auranofin," and can also be generated by treatment of rHA with Et,PAuCl. Firstly DIN-ICP-MS was used to determine Au concentrations for Et,PAuCl in TRIS buffer in the absence and presence of rHA.Et3PAuCl is solubilized in TRIS by the formation of the complex Et,PAu(TRIS). Since both the accuracy and precision of the measurements were acceptable Table 5 measurements were then made on fractions obtained from similar samples which had been subjected to gel filtration on PDlO columns. The concentration of Au from DIN-ICP-MS analysis of 1 1 Et3PAuC1 albumin was lower than expected. The final albumin concentration after dilution was 0.4 pmol dm- which is within the accepted range (< 1 pmol dm-3). As samples were diluted 2500-fold this would introduce a higher risk of sample loss prior to analysis. The first fraction contained Et,PAu bound to albumin and Table4 Comparison of the effects of protein on count rate for 100 pg 1-' P t and Au standards in 0.1 rnol dmP3 TRIS buffer alone and containing 1 pmol dm-3 HSA (Au) or 1 pmol dm-3 HTF (Pt) Count rate/ions s-' Parameter Is5Pt I9'Au 0.1 rnol dm- TRIS 128 000 227 400 RSD (Yo) 0.7 0.9 0.1 mol dmP3 TRIS+ 1 pmol dm- protein 130 300 222 600 Ratio of count rate in TRIS TRIS +protein 98 RSD (%) 0.8 1.3 RSD (%) 0.3 1 .o 102 the second fraction unbound Au.Whereas most of the Au bound to albumin when the molar ratio of Et,PAuCl albumin was 0.5 1 only 83% was found to be bound at a 1 1 molar ratio Table 6. This is due to the SH content of the protein of ca. 0.8 SH per mole of albumin. The remaining 20% of Cys34 in rHA is blocked perhaps as a sulfenic acid Cys34-S03H and is unavailable for Au binding. A reasonable recovery (ca. 86%) of Au from the PDlO column was observed.The RSD for column recovery was calculated by summing all RSD values involved in each sample analysis. CONCLUSIONS Gold anti-arthritic drugs and Pt anti-cancer drugs are widely used in the clinical field and their mechanisms of action may involve binding to the blood plasma proteins albumin and transferrin. It has been shown that for determinations of Au and Pt ICP-MS in conjunction with DIN offers improved LODs over a wide LDR with high precision compared with conventional PN. The low dead volume of the nebulizer reduced rinse times peak broadening and memory effects. Levels of total dissolved solids were comparable to conven- tional PN despite small injection volumes. Serum albumin plays a central role in the pharmacology of Au drugs and the amount of Au bound to albumin in the same form as in patients treated with the oral drug auranofin correlated with the free thiolate content of the protein.The low flow rates of the DIN (100 p1 min-') are compatible with microcolumn chromatography and reports on speciation studies have Coupling of DIN with capillary electrophoresis has also been achieved3* and it is evident that DIN is a versatile sample introduction system for ICP-MS. The method could find widespread application in the determi- nation of the in vivo distribution of Au anti-arthritic and Pt an ti-cancer drugs. The authors thank the EPSRC BBSRC and Delta Biotechnology for their support of this work. Table 5 Comparison of measured (conc,) and calculated (conc,) Au concentrations for Et,PAuCI in 0.1 rnol dm-3 TRIS buffer with the RSD for n = 3 replicates in the absence and presence of albumin.Samples were diluted 2500-fold for ICP-MS measurement Et,PAuCI concentration/mmol dm -3 Albumin concentration/mmol dm -3 Conc,/conc (YO) RSD % (n=3) 0.5 1.0 0.5 1 .o 0 0 1 .o 1 .o 98.6 101.4 98.6 89.9 2.4 1.7 0.9 1.5 Table6 Determination of the Au content of high relative molecular mass (Au bound to albumin) and low relative molecular mass fractions (unbound Au complex) obtained after passing reaction mixtures of Et,PAuCl as albumin in 0.5 1 and 1 1 molar ratios down a gel filtration column. The RSDs are calculated for n = 3 measurements Au (YO) (RSD in parentheses) Au a1 bumin 0.5 1 1 l Bound Et,PAuCI 95.6 (0.8) 83.0 (2.0) Unbound Et,PAuCl 4.4 (2.5) 17.0 (1.7) PDlO column recovery 85.7 (2.6) 87.3 (4.3) 1034 Journal of Analytical Atomic Spectrometry November 19136 Vol.11REFERENCES 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Sadler P. J. Adv. Inorg. Chem. 1991 36 1. Sadler P. J. and Sue R. E. Metal-Based Drugs 1994 1 107. Ni Dhubhghaill 0. M. and Sadler P. J. Metal Complexes in Cancer Chemotherapy ed. Keppler B. K. VCH Weinheim. 1993 Platinum and Other Metal Complexes in Cancer Chemotherapy ed. Howell S. B. Plenum Press New York 1991. Hoshino T. Masafumi M. Yamamoto M. Shimizu H. Ogawa Y. and Toguchi H. J. Controlled Release 1995 37 75. Herrlinger J. D. Alsen C. Baress R. Hecker U. and U'eidert W. J. Rheumatol. 1982 9 81. Barnham K. J. Cox M. C. Dove Y. Frenkiel T. A.Hoeschele J. D. Mason A. B. Sadler P. J. and Woodworth R. 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ISSN:0267-9477    

DOI:10.1039/JA9961101031

出版商:RSC    

年代:1996

数据来源: RSC