摘要:

Ill 8267 - 9 4 7 7 c 1994 I ; 1 - 5 Typeset printed and bound by The Charlesworth Group Huddersfield England 01484 51707 I I/- one-stop immediate access to all atomic spectrometry literature published since 7 985 including conference papers. jAASbase is a unique database that provides a fully comprehensive up-to-date source of over 23,. 000 analytical atomic spectrometry references. It is designed to meet every atomic spectroscopists information needs - a convenient desktop tool. As a subscriber you will enjoy the following benefits of JAASbase @ Simplicity of use even for the non-specialist @ Economy of effort and expense @ A vast store of references @ Flexibility that fosters thorough searches @ Adaptability - you can add your own data @ Helpdesk and user literature gives added assurance that you can quickly master JAASbase Idealist Software f 21 0.00 $368.00 1994 Subscription Details JAAS Backfile (1 986-93) jAASbase Updates EC €99.00 EC €280.00 EC USA $174.00 USA $490.00 USA (VAT chargeable in the UK) To order JAASbase and for further information please contact Sales and Promotion Department Royal Society of Chemistry Thomas Graham House Science Park Milton Road Cambridge CB4 4WF United Kingdom. TeI +44 (0)223 420066. Fax +44 (0)223 423623. ROYAL SOCIETY OF Information Services

ISSN:0267-9477    

DOI:10.1039/JA99409BP001

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 5N Diary of Conferences and Courses 1994 45th Pittsburgh Conference and Expo- sition on Analytical Chemistry and Applied Spectroscopy February 28-March 4 Chicago IL USA For further information contact Pitts- burgh Conference 300 Penn Center Boulevard Suite 332 Pittsburgh PA 15235-9962 USA. ANATECH 94-4th International Sym- posium on Analytical Techniques for Industrial Process Control April 10-13 Royal Hotel Casino Mandelieu La Napoule France Details can be found in J. Anal. At. Spectrom. 1993 8 48N. For further information contact ANATECH 94 Secretariat Elsevier Advanced Technology Mayfield House 256 Banbury Road Oxford UK OX2 7DH. Telephone +44 (0) 865 512242; fax +44 (0) 865 310981. MARC-I11 Conference April 10-16 Kona Hawaii The Third International Conference on Methods and Applications of Radio-6N JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Analytical Chemistry (MARC-111) will be held in conjunction with BERM-6 April 10-16 1994 at the King Kame- hameha Hotel Kona Hawaii. For further information contact Dr Ned Wogman Battelle Pacific North- west Laboratories PO Box 999 P7-35 Richland WA 99352. Fax 509 376 2373. Sixth International Symposium on Bio- logical and Environmental Reference Materials ( BERMd) Topical Confer- ence of AOAC International April 17-21 The Sixth International Symposium on Biological and Environmental Reference Materials will be held from April 17-21 1994 in Kona Hawaii. The Sixth Symposium will continue this series being held on an approximate two year periodic basis.The excellent exchange of ideas and information docu- mented in the Proceedings of the Fifth Symposium held in May 1992 at Aachen Germany covered a wide vari- ety and scope of information in this topical area. Activities at the Sixth Symposium are expected to both broaden these discussions and to focus on more specific aspects of further research on problems and progress of projects discussed at the previous symposium. Topics The major aim of this symposium series is to bring together efforts in the pro- duction study and use of reference materials in the analytical biological biomedical clinical environmental and nutritional communities. Participants and Costs Participation in the symposium is open to all who are interested in reference materials and standards in the biological and environmental areas. The regis- tration fee will cover attendance at the symposium the ‘Book of Abstracts’ and the published proceedings as well as other activities.Accommodation The symposium will be held in the King Kamehameha Hotel Kona Hawaii. A block of rooms has been set aside for attendees at a special conference rate. Details regarding hotel reservations will be sent with the registration materials upon request. Social/ Guest Programmes A social programme is planned to pro- vide an opportunity for informal con- tacts and discussions among participants. Guest programmes can be organized to take advantage of the scenic attractions of the ‘Big Island’. Details will be available at a later date.For further information contact Dr Wayne R. Wolf BERM-6 Standard Reference Materials Program Bldg. 202 Room 211 National Institute of Stan- dards and Technology Gaithersburg MD 20899 USA. 24th Annual Symposium on Environ- mental Analytical Chemistry May 16-19 Ottawa Canada For further information contact M. Malaiyandi CAEC Chemistry Department Carleton University 1255 Colonel By Drive Ottawa Ontario Canada. .International Symposium on Micro- chemical Techniques (ISM ’94) May 16-20 Montreux Switzerland Details can be found in J. Anal. At. Spectrom. 1993 8 63N. For further information contact Nicko & C.R.I. Associes 7 Rue d’Argout F-75002 Paris France. Telephone + 33-1-42 334766 fax + 33-1-40 41 92 41. ASMS Short Courses on Mass Spectrometry May 22-29 Hyatt Regency Hotel Chicago IL USA Introduction to Interpretation of Mass Spectra Advanced Interpretation of Mass Spectra LC-MS The Art and the Practice GC-MS for Environmental Analysis Practical MS-MS Analysis 42nd ASMS Conference on Mass Spec- trometry and Allied Topics May 29-June 3 Hyatt Regency Hotel Chicago IL USA For further information contact Judith A.Sjoberg ASMS 815 Don Gaspar Sante Fe NM 87501 USA. Telephone (505) 989-4517; fax (505) 989-1073. Scandinavian Symposium on Infrared and Raman Spectroscopy SSIR-94 May 30-June 1 Department of Chemistry University of Bergen N-5007 Bergen Norway Details can be found in J. Anal. At. Spectrom. 1993 8 48N. For further information contact Dr Alfred A. Christy Department of Chemistry University of Bergen. Tele- phone + 47-55-213363); fax +47-55- 329058).Laila Kyrkjebo Department of Chemistry University of Bergen telephone + 47-55-213342). Biosensors ’94 The Third World Congress on Biosensors June 1-3 New Orleans LA USA Details can be found in J. Anal. At. Spectrom. 1993 8,42N. For further information contact Kay Russell Conference Department Elsev- ier Advanced Technology Mayfield House 256 Banbury Road Oxford UK OX2 7DH. Telephone +44 (0) 865 512242; fax +44 (0) 865 310981. 6th International Conference on Flow Analysis June 8-11 Toledo Spain Details can be found in J. Anal. At. Spectrom. 1993 8 42N. For further information contact M. Valcarcel/M. D. Luque de Castro Flow Analysis VI Departamento de Quimica Analitica Facultad de Ciencias E-14004 Cordoba Spain. Telephone 34 57 218616; fax 34 57 218606.Short Course in Radioisotope Techniques June 19-24 Loughborough University of Technology Loughborough UK The course is designed to provide scien- tists in industry and research with a broad outline of current radiochemical methods and will also provide training in specialist aspects of radiochemistry. Lectures The lecture course includes such subjects as fundamentals of radioactivity; prin- ciples and operation of counting equip- ment; spectrometry; liquid scintillation counting; radiochromatography; radi- ation hazards and control; legal aspects; application in industry; analytical chem- istry; and organic chemistry and biology. Delegates will be provided with copies of lecture notes experiment sheets and other relevant literature.Practical Work The wide range of practical work available is readily adjustable to suitJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 7N individual interests. Experimental work available includes Physical properties of radiation charac- teristics of various types of counter. Geiger proportional beta and gamma scintillation semi-conductors low-level counting spectrometry Cerenkov counting. Application in organic chemistry and biochemistry. C14 and H3 labelling. Liquid scintillation counting quenching multiple labelling. Application in analysis. Isotopic dilution analysis radioimmunoassay radiochro- matography. Energy dispersive X-ray fluorescence spectrometry. Application in physical and inorganic chemistry. Measurement of adsorption diffusion dissociation constants.Separ- ation by ion exchange solvent extrac- tion etc. Radiation chemistry. Fees The fee for the course is E830. The fee includes full accommodation in the new short course centre Burleigh Court. Alternative accommodation can be obtained in local hotels. The non- residential delegate rate is &565. For further information contact Dr Peter Warwick Department of Chemis- try Loughborough University of Tech- nology Loughborough Leicestershire UK LEll 3TU. Telephone (0509) 222585; fax (0509) 233163. 7th International Symposium on Reso- nance Ionization Spectroscopy and Its Applications (RIS-94) July 3-8 Bern kastel- K ues Germany Details can be found in J. Anal. At. Spectrom. 1993 8 59N. For further information contact RIS-94 R. Chitty Institut fur Physik Universitat Mainz Postfach 39 80 D-55092 Mainz Germany telephone 0049-6131-393628; fax 0049-6131- 393428; telex 418-7155 phmz d; email RIS94@VIPMZA.PHYSIK.UNI-MAINZ.DE. Spectroscopy Across the Spectrum I V Techniques and Applications of Analytical Spectroscopy July 11-14 University of East Anglia Norwich U K Details can be found in J. Anal. At. Spectrom. 1993 8 59N. For further information contact Dr D. L. Andrews School of Chemical Sciences University of East Anglia Norwich UK NR4 7TJ. Fax 0603 25936. Seventh Biennial National Atomic Spec- troscopy Symposium July 20-22 University of Hull Hull U K The aim of this three-day meeting is to promote and encourage developments in both fundamental and applied atomic spectroscopy including ICP-MS and XRF by providing a friendly environ- ment where delegates can meet formally and informally to exchange ideas views and results.The Opening Ceremony for the Sym- posium will be at 1.30 pm on Wednesday 20 July. Workshop A workshop is planned for Tuesday 19 July pm and Wednesday 20 July am to address the problems of sampling and sample introduction in atomic spec- troscopy. The afternoon session will be a series of lectures to include statistical techniques whilst the morning will focus more on the practical aspects of the subject to include parallel sessions on vapour generation batch and on-line microwave digestion slurry methods and procedures for XRF analysis. Separate registration is required for the workshop. Scientific Programme Each session in the scientific programme will incorporate a plenary lecture given by a world-renowned spectroscopist. Otherwise there will be two parallel streams each headed by an invited speaker and followed by contributed lectures of 20 minutes length.There will also be two poster sessions. Submission of Papers Papers should discuss original unpub- lished work. Three copies of the abstracts must be submitted before 31 March 1994. Authors will be informed by mid-April 1994 of the acceptance or rejection of submitted papers and whether presen- tation will be by lecture or poster. Manuscripts of accepted papers will be considered for publication following the usual peer review process in a special issue (March 1995) of the Journal of Analytical Atomic Spectrometry (JAAS). Poster sessions will be on Wednesday and Thursday.Each poster will be displayed for a day and authors are asked to attend their posters from 5.15 pm to 6.15 pm during the informal mixer sessions when drinks will be provided. Plenary Lectures Professor R.F. Browner (Georgia Insti- tute of Technology Atlanta GA USA) Sample introduction the Achilles heel of ICP-AES and ICP-MS; part I1 Dr H.T. Delves (Trace Element Unit University of Southampton UK) Clini- cal and environmental applications of atomic spectrometry. Professor R.S. Houk (Ames Laboratory Ames IA USA) Innovations in elemen- tal analysis by mass spectrometry. Dr R. Klockenkamper (ISAS Dort- mund Germany) Total reflection X-ray fluorescence - physical principles and analytical applications. Dr D.L. Styris (Battelle Pacific Labora- tories Richland WA USA) The eluci- dation of electrothermal atomizer mechanisms - surface science at very high temperatures.Invited Lectures Dr H. Crews (MAFF Norwich UK) Multi-element analysis of biological materials by ICP-MS - the reality! Professor S. Greenfield (Loughborough University of Technology UK) The ICP as source and atom/ion reservoir. Dr G.M. Greenway (University of Hull UK) On-line sample treatment for atomic spectrometric detection. Dr D.J. Halls (Royal Infirmary Glas- gow UK) Analytical minimalism applied to the determination of trace elements in clinical and biological samples. Dr P.J. Potts (The Open University Milton Keynes UK) Design consider- ations for a laboratory X-ray fluor- escence microprobe; optimizing the use of glass capillary collimators based on results from a ray-tracing program.Dr I.L. Shuttler (Bodenseewerk Perkin- Elmer Uberlingen Germany) Recent developments in ETAAS instrum- entation. Dr K.C. Thompson (Yorkshire Water Enterprises Ltd. Sheffield UK) The utilization of vapour generation tech- niques in environmental analysis. Dr C.T. Tye (VG Elemental Winsford Cheshire UK) Interfacing plasma sources with mass spectrometers - is it art or science? Mrs K.A. Wolnik (US Food and Drug Administration Cincinnati OH USA) Applicants of ICP-ES and ICP-MS to forensic analysis. Dr K.W. Frech (University of Umea Umea Sweden) Atomic spectrometric techniques for the determination of mer- cury and its compounds in environmen- tal samples and petroleum products.8N JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Exhibition An exhibition of suppliers of commercial atomic spectroscopic instrumentation accessories and ancillary equipment as well as scientific publishers will form an important part of the 7th BNASS. Lead- ing instrument companies have already indicated that they will be attending. Venue The historic city of Kingston upon Hull has been the business and commercial centre of the old East Riding of Yorkshire for centuries. In more recent times the city is remembered for its fishing fleets but today there is a more diverse commercial community including a strong presence by the chemical industry. The University of Hull was founded in 1927 and has grown steadily over the years The School of Chemistry is home to one of the UKs premier analytical chemistry research schools.Social Programme The Symposium Dinner will be held on Thursday 21 July in the Myton Room Staff House University of Hull. Del- egates staying for the Friday evening will have the opportunity to carry out a hands-on spectroscopic experience at the Laserquest followed by a barbecue at Thwaite Hall. Accommodation Accommodation for delegates to the 7th BNASS will be in a University of Hull hall of residence with individual study bedrooms. As an alternative lists of local hotels and guest houses can be supplied. Student Bursaries Younger scientists are particularly wel- come at BNASS meetings and students are encouraged to submit poster or lecture presentations. There will be prizes for the best student poster lecture.Funding has been received from several organizations for a limited number of bursaries to the value of El20 each to be offered to research students. The bursaries will be contributions towards the cost of accommodation and regis- tration; travel expenses will remain the responsibility of the attendee. Applicants for student bursaries should submit a brief (one-page) curriculum vitae of their career since leaving school together with not more than 500 words outlining their current research work in atomic spectroscopy. Applications should be signed by both applicant and supervisor and submitted before 31 March 1994 to Dr S.J. Haswell Sec- retary 7th BNASS Organizing Com- mittee School of Chemistry University of Hull Hull UK HU6 7RX. For further information contact Dr Steve Hill Department of Environ- mental Sciences University of Plymouth Drake Circus Plymouth Devon UK PL4 8AA.13th International Mass Spectrometry Conference August 29-September 2 Budapest Hungary For further information contact Hung- arian Chemical Society; FO u. 68 H-1027 Budapest Hungary. Telephone 361 201 6883; fax 316 15 61215. EUCMOS XXII XXII European Con- gress on Molecular Spectroscopy September 11-16 Essen Germany Details can be found in J. Anal. At. Spectrom. 1993 8 49N. For further details contact Gesellschaft Deutscher Chemiker Abt. Tagungen PO Box 90 04 40 W-6000 Frankfurt 90 Germany. Telephone + 49 697917-366; fax +49 69 7917-475; telex 4 170 497 gdch d. Geoanalysis 9 4 An International Sym- posium on the Analysis of Geological and Environmental Materials September 18-22 Charlotte Mason Conference Centre Ambleside UK Details can be found in J.Anal. At. Spectrorn. 1993 8 49N. For further information contact Mr D. L. Miles Analytical Geochemistry Group British Geological Survey Kingsley Dunham Centre Keyworth UK NG12 5GG. Telephone 0602 363100; fax 0602 363200. 7th International Symposium on Environ- mental Radiochemical Analysis September 21-23 Bournemouth UK Dates to Note Synopses of papers January 28 1994. Final date for registration July 15 1994. For further details contact Dr. P. Warwick Department of Chemistry Loughborough University of Tech- nology Loughborough Leices tershire UK LEll 3TU. Telephone 0509 222585 or 0509 222545; fax 0509 233163. 1994 European Workshop in Chemometrics September 25-30 Bristol University Bristol U K The workshop will be organized into sessions based on themes each session will be divided into lectures discussions hands-on software and videos as appro- priate.Topics covered will include factor analysis; calibration; experimental design and optimization; maximum entropy and Bayesian statistics; exploratory data analysis; classification and clustering and quantitative structure activity relationships. For further information contact Janice Green School of Chemistry University of Bristol Cantock's Close Bristol BS8 lTS UK. Telephone (0272) 303030 extn. 4421 or (0272) 303672; fax (0272) 251295. 21st Annual Conference of the Federation of Analytical Chemistry and Spectroscopy Societies (FACSS) October 2-7 St. Louis MO USA Details can be found in J.Anal. At. Spectrom. 1994 9 (1). For further information contact FACSS 198 Thomas Johnson Drive Suite S-2 Frederick MD 21 702-43 17 USA. Tele- phone (301) 846 4797. 6th International Colloquium on Solid Sampling With Atomic Spectroscopy October 11-13 Amsterdam The Netherlands Details can be found in J. Anal. At. Spectrom. 1993 8 59N. For further information contact Dr R. F. M. Herber Coronel Labora- tory University of Amsterdam Meiberg- dreef 15 NL-1105 AZ Amsterdam The Net herlands. Third Rio Symposium on Atomic Spectrometry November 6-12 Venezuela Details can be found in J. Anal. At. Spectrom. 1993 8 64N. For further information contact Pro- fessor Jose Alvarado Universidad Simon Bolivar Departamento de Quimica Laboratorio de Absorcion Atbmica,JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 9N Apartado postal No. 89000 Caracas 1080-A Venezuela. Fax (0058-2-) 938322 / 57 19 1341 5763355 1962 1695. Analytica '944econd National Sym- posium on Analytical Science December 1994 Western Cape South Africa Detals can be found in J. Anal. At. Spectrom. 1993 8 60N. For further information contact Dr I. M. Moodie c/o PO Box 1970 Tygerberg 7505 South Africa. Fax 021-932-4575. 1995 Colloquium Spectroscopicum Inter- nationale (CSI) XXIX August 27-September 1 1995 Leipzig Germany Details can be found in J. Anal. At. Spectrom. 1993 8 50N. For further details contact Prof. Dr. H. Nickel Universitat Leipzig FB Chemie FG Atomspektroskopie Lin- nestr. 3 D-04103 Leipzig Germany. Telephone and fax (49)-341-6858377. UFZ-Centre for Environmental Re- search Department of Analytical Chem- istry Permoserstr.15 D-043 18 Leipzig Germany. Telephone (49)-34 1-23 5-2370; fax -2625. Future Issues will include- The March issue of JAAS will consist of Post-Symposium on Analytical Appli- Plasma Source Mass Spectrometry and papers from work presented at the cations of Glow Discharge in Optical the Post-Symposium on Graphite Atom- XXVIII Colloquium Spectroscopicum and Mass Spectrometry also held in izer Techniques in Analytical Spec- Internationale held in York UK; the York; the 5th Surrey Conference on troscopy (both held in Durham UK). Analytical Division Royal Society of Chemistry ATOMIC SPECTROSCOPY PROBING THE ENVIRONMENT 25th Anniversary Meeting of The Atomic Spectroscopy Group Thursday 24 March 1994 Charlotte Mason Conference Centre Ambleside Speakers include Prof A Sanz-Medel Prof M Cresser Dr M Foulkes Mr E R Newman Dr P J Watkins Dr P J Potts plus two of the founder members of the Atomic Spectroscopy Group Dr J B Dawson and Dr W J Price.Further details Ms J M Cook British Geological Survey Keyworth Nottingham NG12 5GG. Telephone 0602 363330; Fax 0602 363200.JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 9N Apartado postal No. 89000 Caracas 1080-A Venezuela. Fax (0058-2-) 938322 / 57 19 1341 5763355 1962 1695. Analytica '944econd National Sym- posium on Analytical Science December 1994 Western Cape South Africa Detals can be found in J. Anal. At. Spectrom. 1993 8 60N. For further information contact Dr I.M. Moodie c/o PO Box 1970 Tygerberg 7505 South Africa. Fax 021-932-4575. 1995 Colloquium Spectroscopicum Inter- nationale (CSI) XXIX August 27-September 1 1995 Leipzig Germany Details can be found in J. Anal. At. Spectrom. 1993 8 50N. For further details contact Prof. Dr. H. Nickel Universitat Leipzig FB Chemie FG Atomspektroskopie Lin- nestr. 3 D-04103 Leipzig Germany. Telephone and fax (49)-341-6858377. UFZ-Centre for Environmental Re- search Department of Analytical Chem- istry Permoserstr. 15 D-043 18 Leipzig Germany. Telephone (49)-34 1-23 5-2370; fax -2625. Future Issues will include- The March issue of JAAS will consist of Post-Symposium on Analytical Appli- Plasma Source Mass Spectrometry and papers from work presented at the cations of Glow Discharge in Optical the Post-Symposium on Graphite Atom- XXVIII Colloquium Spectroscopicum and Mass Spectrometry also held in izer Techniques in Analytical Spec- Internationale held in York UK; the York; the 5th Surrey Conference on troscopy (both held in Durham UK). Analytical Division Royal Society of Chemistry ATOMIC SPECTROSCOPY PROBING THE ENVIRONMENT 25th Anniversary Meeting of The Atomic Spectroscopy Group Thursday 24 March 1994 Charlotte Mason Conference Centre Ambleside Speakers include Prof A Sanz-Medel Prof M Cresser Dr M Foulkes Mr E R Newman Dr P J Watkins Dr P J Potts plus two of the founder members of the Atomic Spectroscopy Group Dr J B Dawson and Dr W J Price. Further details Ms J M Cook British Geological Survey Keyworth Nottingham NG12 5GG. Telephone 0602 363330; Fax 0602 363200.

ISSN:0267-9477    

DOI:10.1039/JA99409005Nc

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

1995 European Winter Conference on Plasma Spectrochemistry 8-13 January 1995 CAMBRIDGE UK Short Courses A series of short courses of one half day duration will take place on Sunday 8th January. Notes and tuition material will be distributed with each course. Courses 1 and 2 Short Courses on ICP-MS Professor R.S. Houk Ames Laboratory Iowa State University USA Course 1 (AM) Instrumentation and Theory The course will cover fundamental aspects of ICP-MS including:- a) Molecular beam sampling b) Quadrupole and high resolution c) Vacuum technology d) Ion sources e) Detection systems and data hand1 ing f) Sample introduction technologies analys ers Course 2 (PM) Advanced Topics The course will cover more advanced topics on ICP-MS particularly relevant to problem solving. Each topic will be illustrated with relevant applications examples.a) Interferences (spectroscopic and non-spectroscopic and methods of alleviation b) Isotopic analysis c) Chromatographic methods d) Overview of commercial instrumentation Course 3 (PM) Sample Preparation for ICPs Dr S.J. Haswell Hull University UK The course will focus on important aspects of sampling and sample preparation with particular emphasis on ICP measurements. a) Batch methods f o r wet oxidation b) Recent trends in microwave preparation for ICP-MS atomic spectrometry general analytical techniques c) On-line sample preparation d) Extraction methods e) On-line chemical processing f) Miniaturization Course 4 (PM) Speciation Professor O.X. Donard University of Bordeaux France The course will focus on practical aspects of speciation analysis with particular emphasis on ICP and other plasma sampling systems.Sample collection and handling preservation and preparation prior to injection into hyphenated systems using atomic spectrometry and ICP-AES or ICP-MS as detectors will be illustrated with applications from current topical fields . a) Sampling and sample pretreatment b) Separative techniques Differential chemistry Gas liquid ion and SCF c ) Interfacing chromatography techniques to ICPs and other plasma sources and detectors chromatographies Course 5 (AM) Quality Systems in the Laboratory Professor L. Ebdon Dr E.H. Evans University of Plymouth UK The course will discuss how high quality analytical data can be produced in the laboratory that are accurate reliable and adequate f o r the intended purpose.a) Quality assurance principles b) Sampling and sample preparation c) Personnel aspects d) Statistics for quality control e Use of reference materials and f) Equipment and records maintenance g) Audits and accreditation. traceability Course 6 (AM) Sample Presentation for ICPS Dr C McLeod Sheffield Hallam University UK The course is intended as a problem solving workshop and will attempt to rationalise the choice of sampling system for ICP spectrometries by use of practical examples. a) Nebulisation techniques Traditional and high efficiency The role of desolvation Hydride Other vapour techniques e . g . b) Vapour generation Hg oso c) Microsampling systems d) Flow injection e) Laser ablation1995 European Winter Conference on Plasma Spectrochemistry 8-13 January 1995 CAMBRIDGE UK Short Courses A series of short courses of one half day duration will take place on Sunday 8th January. Notes and tuition material will be distributed with each course.Courses 1 and 2 Short Courses on ICP-MS Professor R.S. Houk Ames Laboratory Iowa State University USA Course 1 (AM) Instrumentation and Theory The course will cover fundamental aspects of ICP-MS including:- a) Molecular beam sampling b) Quadrupole and high resolution c) Vacuum technology d) Ion sources e) Detection systems and data hand1 ing f) Sample introduction technologies analys ers Course 2 (PM) Advanced Topics The course will cover more advanced topics on ICP-MS particularly relevant to problem solving. Each topic will be illustrated with relevant applications examples.a) Interferences (spectroscopic and non-spectroscopic and methods of alleviation b) Isotopic analysis c) Chromatographic methods d) Overview of commercial instrumentation Course 3 (PM) Sample Preparation for ICPs Dr S.J. Haswell Hull University UK The course will focus on important aspects of sampling and sample preparation with particular emphasis on ICP measurements. a) Batch methods f o r wet oxidation b) Recent trends in microwave preparation for ICP-MS atomic spectrometry general analytical techniques c) On-line sample preparation d) Extraction methods e) On-line chemical processing f) Miniaturization Course 4 (PM) Speciation Professor O.X. Donard University of Bordeaux France The course will focus on practical aspects of speciation analysis with particular emphasis on ICP and other plasma sampling systems.Sample collection and handling preservation and preparation prior to injection into hyphenated systems using atomic spectrometry and ICP-AES or ICP-MS as detectors will be illustrated with applications from current topical fields . a) Sampling and sample pretreatment b) Separative techniques Differential chemistry Gas liquid ion and SCF c ) Interfacing chromatography techniques to ICPs and other plasma sources and detectors chromatographies Course 5 (AM) Quality Systems in the Laboratory Professor L. Ebdon Dr E.H. Evans University of Plymouth UK The course will discuss how high quality analytical data can be produced in the laboratory that are accurate reliable and adequate f o r the intended purpose. a) Quality assurance principles b) Sampling and sample preparation c) Personnel aspects d) Statistics for quality control e Use of reference materials and f) Equipment and records maintenance g) Audits and accreditation. traceability Course 6 (AM) Sample Presentation for ICPS Dr C McLeod Sheffield Hallam University UK The course is intended as a problem solving workshop and will attempt to rationalise the choice of sampling system for ICP spectrometries by use of practical examples. a) Nebulisation techniques Traditional and high efficiency The role of desolvation Hydride Other vapour techniques e . g . b) Vapour generation Hg oso c) Microsampling systems d) Flow injection e) Laser ablation

ISSN:0267-9477    

DOI:10.1039/JA99409FX021

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

1995 European Winter Conference on Plasma Spectrochemistry 8-13 January 1995 CAMBRIDGE UK Short Courses A series of short courses of one half day duration will take place on Sunday 8th January. Notes and tuition material will be distributed with each course. Courses 1 and 2 Short Courses on ICP-MS Professor R.S. Houk Ames Laboratory Iowa State University USA Course 1 (AM) Instrumentation and Theory The course will cover fundamental aspects of ICP-MS including:- a) Molecular beam sampling b) Quadrupole and high resolution c) Vacuum technology d) Ion sources e) Detection systems and data hand1 ing f) Sample introduction technologies analys ers Course 2 (PM) Advanced Topics The course will cover more advanced topics on ICP-MS particularly relevant to problem solving. Each topic will be illustrated with relevant applications examples.a) Interferences (spectroscopic and non-spectroscopic and methods of alleviation b) Isotopic analysis c) Chromatographic methods d) Overview of commercial instrumentation Course 3 (PM) Sample Preparation for ICPs Dr S.J. Haswell Hull University UK The course will focus on important aspects of sampling and sample preparation with particular emphasis on ICP measurements. a) Batch methods f o r wet oxidation b) Recent trends in microwave preparation for ICP-MS atomic spectrometry general analytical techniques c) On-line sample preparation d) Extraction methods e) On-line chemical processing f) Miniaturization Course 4 (PM) Speciation Professor O.X. Donard University of Bordeaux France The course will focus on practical aspects of speciation analysis with particular emphasis on ICP and other plasma sampling systems.Sample collection and handling preservation and preparation prior to injection into hyphenated systems using atomic spectrometry and ICP-AES or ICP-MS as detectors will be illustrated with applications from current topical fields . a) Sampling and sample pretreatment b) Separative techniques Differential chemistry Gas liquid ion and SCF c ) Interfacing chromatography techniques to ICPs and other plasma sources and detectors chromatographies Course 5 (AM) Quality Systems in the Laboratory Professor L. Ebdon Dr E.H. Evans University of Plymouth UK The course will discuss how high quality analytical data can be produced in the laboratory that are accurate reliable and adequate f o r the intended purpose.a) Quality assurance principles b) Sampling and sample preparation c) Personnel aspects d) Statistics for quality control e Use of reference materials and f) Equipment and records maintenance g) Audits and accreditation. traceability Course 6 (AM) Sample Presentation for ICPS Dr C McLeod Sheffield Hallam University UK The course is intended as a problem solving workshop and will attempt to rationalise the choice of sampling system for ICP spectrometries by use of practical examples. a) Nebulisation techniques Traditional and high efficiency The role of desolvation Hydride Other vapour techniques e . g . b) Vapour generation Hg oso c) Microsampling systems d) Flow injection e) Laser ablation1995 European Winter Conference on Plasma Spectrochemistry 8-13 January 1995 CAMBRIDGE UK Short Courses A series of short courses of one half day duration will take place on Sunday 8th January. Notes and tuition material will be distributed with each course.Courses 1 and 2 Short Courses on ICP-MS Professor R.S. Houk Ames Laboratory Iowa State University USA Course 1 (AM) Instrumentation and Theory The course will cover fundamental aspects of ICP-MS including:- a) Molecular beam sampling b) Quadrupole and high resolution c) Vacuum technology d) Ion sources e) Detection systems and data hand1 ing f) Sample introduction technologies analys ers Course 2 (PM) Advanced Topics The course will cover more advanced topics on ICP-MS particularly relevant to problem solving. Each topic will be illustrated with relevant applications examples.a) Interferences (spectroscopic and non-spectroscopic and methods of alleviation b) Isotopic analysis c) Chromatographic methods d) Overview of commercial instrumentation Course 3 (PM) Sample Preparation for ICPs Dr S.J. Haswell Hull University UK The course will focus on important aspects of sampling and sample preparation with particular emphasis on ICP measurements. a) Batch methods f o r wet oxidation b) Recent trends in microwave preparation for ICP-MS atomic spectrometry general analytical techniques c) On-line sample preparation d) Extraction methods e) On-line chemical processing f) Miniaturization Course 4 (PM) Speciation Professor O.X. Donard University of Bordeaux France The course will focus on practical aspects of speciation analysis with particular emphasis on ICP and other plasma sampling systems.Sample collection and handling preservation and preparation prior to injection into hyphenated systems using atomic spectrometry and ICP-AES or ICP-MS as detectors will be illustrated with applications from current topical fields . a) Sampling and sample pretreatment b) Separative techniques Differential chemistry Gas liquid ion and SCF c ) Interfacing chromatography techniques to ICPs and other plasma sources and detectors chromatographies Course 5 (AM) Quality Systems in the Laboratory Professor L. Ebdon Dr E.H. Evans University of Plymouth UK The course will discuss how high quality analytical data can be produced in the laboratory that are accurate reliable and adequate f o r the intended purpose. a) Quality assurance principles b) Sampling and sample preparation c) Personnel aspects d) Statistics for quality control e Use of reference materials and f) Equipment and records maintenance g) Audits and accreditation. traceability Course 6 (AM) Sample Presentation for ICPS Dr C McLeod Sheffield Hallam University UK The course is intended as a problem solving workshop and will attempt to rationalise the choice of sampling system for ICP spectrometries by use of practical examples. a) Nebulisation techniques Traditional and high efficiency The role of desolvation Hydride Other vapour techniques e . g . b) Vapour generation Hg oso c) Microsampling systems d) Flow injection e) Laser ablation

ISSN:0267-9477    

DOI:10.1039/JA99409BX023

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 25 R ATOMIC SPECTROMETRY UPDATE-ENVIRONMENTAL ANALYSIS Malcolm S. Cresser* Department of Plant and Soil Science Aberdeen University Meston Building Old Aberdeen UK At39 2UE Janet Ar mst ro ng Forth River Purification Board Heriot Watt Research Park Avenue North Riccarton Edinburgh UK EH74 4AP Jennifer Cook British Geological Survey Keyworth Nottingham UK NG 72 5GG John R. Dean Department of Chemical and Life Sciences University of Northumbria at Newcastle Ellison Building Newcastle upon Tyne UK NE18ST Peter Watkins Department of Geology Imperial College of Science Technology and Medicine Royal School of Mines Prince Consort Road London UK SW7 2BP Mark Cave British Geological Survey Keyworth Nottingham UK NG 72 5GG 1 2 3 4 Summary of Contents Air Analysis 1.1 Sample Collection and Pre-treatment 1.2.Instrumental Analysis Table 1. Summary of Analyses of Air and Particulates Water Analysis 2.1 Sample Preparation 2.1.1. Microwave digestion 2.1.2. Chelating resins 2.1.3. Ion-exchange resins 2.1.4. Solid sorbants 2.1 5. Solvent extraction 2.1.6. Precipitation and flotation techniques 2.1.7. Hydride and cold vapour generation 2.1.8. Speciation 2.2. Instrumental Analysis 2.2.1. Atomic absorption spectrometry 2.2.2. Atomic emission 2.2.3. X- Ray f I uorescen ce 2.2.4. Mass spectrometry Table 2. Summary of Water Analyses Analysis of Soils Plants and Related Materials 3.1. 3.2. 3.3. 3.4. 3.5 3.6. 3.7. 3.8. I Soil and Plant Reference Materials Sample Preparation 3.2.1. Sample dissolution 3.2.2.Slurry preparation 3.2.3. Solvent extraction 3.2.4. Other separation procedures 3.2.5. Speciation studies Developments in Atomic Absorption Spectrometry Developments in Atomic Emission Spectrometry Developments in Atomic Fluorescence Spectrometry and Related Techniques Developments in Mass Spectrometry Developments in X-Ray Fluorescence Spectrometry Laser Microprobe Mass Spectrometry Table 3. Summary of Analyses of Soils Plants and Related Materials Analysis of Geological Materials 4.1. Introduction 4.2. Sample Preparation 4.2.1. Solid sample introduction 4.2.2. Decomposition with acids *Review Co-ordinator to whom correspondence should be addressed.26 R 4.2.3. 4.2.4. 4.2.5. JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 Decomposition using fusion Decomposition by other methods Separation and preconcentration 4.2.5.1 Solvent extraction 4.2.5.2.Ion exchange 4.2.5.3. Co prec i pit at ion 4.2.5.4. Vapour generation 4.3. Instrumental Analysis 4.3.1. Atomic absorption spectrometry 4.3.2. Atomic emission spectrometry 4.3.3. Inductively coupled plasma mass spectrometry 4.3.4. Other mass spectrometric methods 4.3.5. X-Ray methods 4.3.6. Neutron activation analysis Table 4. Summary of Analyses of Geological Materials This is the ninth annual review published in JAAS of the application of atomic spectrometry based procedures to the chemical analysis of environmental samples. The format used is very similar to that of previous years. The most noticeable trend over the past 12 months has been an increase in the exploitation of the analytical power of ICP-MS and MS techniques generally.Even in the analysis of air some very interesting developments using isotopic tracers have been reported. The availability of a capacity for ultra-trace determinations however has for several workers served to highlight the need for clean sampling and sample handling techniques if sensible results are to be obtained. With the wider use of ICP-MS a better understanding of polyatomic ion interference effects is also starting to emerge In most years one or two elements seem to attract particular attention in environmental research. At present determination and speciation of Cr seem to be attracting considerable interest. 1. AIR ANALYSIS Publications and conference reports over the past review year have shown no obvious trends in air analysis.In the previous two years a significant number of papers concerned with atmospheric particulate characterization were published. This year only a handful of papers covering this topic have appeared suggesting that environmental analysis is prone to the whims of fashion. Various classic studies continue to resurface such as Pb determination in street dust (93/4104) whilst an up and coming area may well be monitoring of Pt from car catalyst exhausts (93/C1344). Chromium continues to be an element of some concern and a wide ranging review discussing sample treatment and instrumental parameters has been published (93/4024). A more general review looking at analysis of airborne particles in workplace atmospheres has been written by Septon (93/625) based on 105 refs.It considers all aspects of air analysis from sample collection through to analysis by AAS. Table 1 summarizes the significant papers and reports on aspects of air analysis which have appeared over the past 12 months. 1.1. Sample Collection and Pre-treatment The use of models to assess the impact of air particulates on the environment is important as is data collection to test the model. To assess the impact of coal fired power plants on the Grand Canyon particulate samples from three emission points were collected using a plume simulating dilution sampler. A chemical mass balance receptor model can be devised following sample analysis to facilitate subsequent predictions of depos- ition trends (93/1890).Air filters remain as the standard method of collecting atmospheric particulate samples. Certijied reference material Jilters (SRM 2676c) were prepared and used to determine the levels of potentially toxic elements in industrial atmospheres. A random sample of 2% of the stock was taken for analytical characterization. The filter substrate was readily soluble and no matrix interferences were observed when the samples were analysed by ID-ICP-MS. Cadmium Pb and Zn were determined by ID whilst cobalt was used as an internal standard for the determination of monoisotopic Mn (93/C 1300). Various devices have been utilized to improve LODs or reduce sample preparation time. Altman (93/C987) employed a device which collects samples by electrostatic precipitation from pumped air directly onto a graphite atomizer. The sample can be collected in a matter of minutes and sensitivity depends on the volume of air pumped.Direct collection onto a graphite tube was also employed by Hoffmann et al. (93/C3036) who used a porous tube as a filter for airborne particulates. The tubes were then used directly for furnace atomic non-thermal excitation spectrometric analysis. An alternative method was devised by Carneiro et al. (93/C144) to minimize the risk of contamination and loss. The samples were collected on glass fibre filters. They were then cut into small pieces and transferred to ETAAS autosampler cups. A microdigestion procedure was performed directly in the autosampler cup by adding 150 pl of HNO + H,SO + HF (1 + 1 + 1) and ultrasonicating for 10 min.Saturated H,BO solution and de-ionized water were added up to 1 ml. After homogenization the cup was presented for analysis. Good agreement was found between certified and determined values. Dust from the cement industry poses an environmental problem. To characterize the source of dust Moore (93/3807) has devised a rapid and accurate method for determining the composition of dusts. Small samples of dust about 0.07 g collected with directional collection apparatus were fused with a flux consisting of 80% lithium tetraborate and 20% lithium fluoride. The homogeneous glass fusion disc produced was analysed for a range of elements by XRF. Sampling methods for the determination of volatile inorganic species in workroom air have been described by Hetland et al.(93/558). They employed activated charcoal to collect Fe(CO)5 and Ni(CO) whereas ASH PH3 and SbH were collected on AgN0,-impregnated pads in a double-filter air cassette. The AgN0,-impregnated pads were shown to trap hydrides with greater than 99.9% efficiency. The main factors affecting the absorption capacity of the activated charcoal were air flow and total volume of air sampled. Organic tin@) substances were detected in office air after the improper use of tributyl tin@) oxide-based fungicide (93/3271). The samples were col- lected in absorbers containing HNO filtered and mineralized The total content of Bu3Sn Bu,Sn and BuSn as Sn was determined by AAS and the concentration was found to deplete slowly over time.JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Table 1 SUMMARY O F ANALYSES OF AIR AND PARTICULATES 27 R Technique; atomization; analyte form* AA;H y ; L Element Matrix As Fly ash CRM Sample treatment/commentst used to introduce samples. Matrix elements gave lower interference in comparison to batch hydride method On-line procedure to convert As to lower oxidation state for hydride formation. Continuous HG combined with conventional nebulization Hydride collected on AgNO impregnated filters Sample digested in aqua regia. Flow injection HG Reference 93/C106 93/c240 931558 9313207 9313420 93/4088 9312318 9312535 9312648 9313593 93/c1300 9312390 9313989 93/4006 As NIST Coal fly ash SRM AE;ICP Hy;L As As Workroom air Cloud aerosol AA;ETA;- NAA,-;- AE;ICP;- A A t Hy;- AA,-;L High volume sampler with cellulose filters used to collect samples.Thirty 1 cm diameter discs pressed to form pellet Comparison of digests using HC104 HF and HNO,. Effect of temperature and treatment time especially using HF to digest As discussed dissolution as HBF enriched CO in expired breath. Breath sample of 50 pl analysed within 150 s Accelerator MS allows I4C to be determined. Only 10 mg of C required equivalent to 0.05 m3 of air I4CO used as an indicator of OH 13C-labelled substrate fed to mice and men. 13C02 in expired air transported by pump to quadruple MS system. Valve system allows alternation between expired air and a standard Substrate readily soluble and gave no matrix interference. IDMS used to give high accuracy results Cellulose ester filters decomposed with concentrated HNO at 165 "C.Resulting gel filtered filtrate evaporated to dryness and residue dissolved in 10% HNO,. Comparison with voltametric procedure Fly ash formed into Pozzolana cement to reduce Cd leaching Selective dissolution allowed removal of Si. Other matrix elements present caused no interference. Sample introduced on graphite probe. Details of furnace programme given Air collected on 5 p PVC membrane filters. CrV1 extracted from filters with acetic acid-sodium acetate buffer and CrV1 isolated with APDC-IBMK. LOD was 1.1 pg 1-' for 20 pl of sample Cellulose ester filters used to collect samples. Flame conditions evaluated High sensitivity X-ray spectrometer used. Satisfactory results obtained Quartz fibre filters spiked with isotopically enriched Cr used to collect samples Enriched CrV1 isotope used to monitor reduction of Cr"' during sample collection.CrV' extracted from filter with 0.1 mol I-' NaOH and preconcentrated by IC. Isotopic composition of CrV' fraction determined Air bubbled through solution containing HF for B On-line GC isotope ratio MS used to analyse 13C Filter media certified at three different levels. See As ref. 9313207 Review of sample pre-treatment and instrumental See Cd ref. 9312390 Iron pentacarbonyl trapped on activated charcoal procedures for Cr determination As Fly ash B C Air Breath AE;ICPL MS;-;G C Nuclear power station stack air Clean air Breath C C Cd SRM 2676c air filter MS;ICPL Cd Atmospheric aerosols AA;-;L Cd c o Fly ash Coal fly ash AA;ETA;L AA;ETA; L Cr Air in a chrome plating plant AA;ETA;L 93/c143 Cr Cr Cr Air Air Incinerator emissions AA;F air-C2H2;L XRF;-;S MS;ICP;L 9311098 9311858 9312253 NAA;-;- AA;ETA;L AA;F;L AA;ETAG AE;ICP;G AA;F;L AA;-;L Cr Cr Cloud aerosol Urban particulate matter 9313207 9314024 Atmospheric aerosols Workroom air 9312390 931558 c u Fe FeC1 and soluble iron salts collected on paper filter.Salts dissolved in hot water prior to determination of Fe (0.25 mg Fe per m3 of air) See As ref. 93/3420 Use of nickel modifier improved signal from Ga 2.46-fold and eliminated matrix interferences allowing use of aqueous calibration standards. Results agreed well with certified values and those obtained after pressure digestion gaseous Hg (10 pg Hg) Gold impregnated sand trap to preconcentrate 93/1218 Fe Workplace air AA;-;L AA;ETA;Sl 9313420 931 1028 Fe Ga Fly ash Coal fly ash AF;cold vapour;G 93/C69 Air28 R Table 1 (continued ) JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Technique; atomization; analyte form* A A;ETA;L Sample treatmentlcommentst Single addition of 15 pg palladium to graphite tube sufficient for 40-60 determinations of Hg. Atomization temperature of 1000 "C possible. Mixture of 95% Ar and 5% H used as purge gas Preconcentration on gold powder (pg m-3) Gold amalgamators used to trap Hg. Other Correlation between Hg in breath and number of MgO collected on membrane filter dissolved in See Cd ref. 93/C1300. Co used as internal standard See As ref. 9313420 Microdigestion in autosampler cup using 150 pl of atmospheric contaminants interfered with amalgam dental amalgam restorations studied HNO (as) (2 4 mg m-3) for Mn determination HN03+H2S04+HF (1 + 1 + 1).Sample ultrasonicated for 10 min. Boric acid and de-ionized water added prior to analysis. Good agreement with certified values See Fe ref. 931558 Reference 931412 93/45 1 931728 9311212 9311215 93/c1300 93/c144 9313420 Element Matrix Hg Coal fly ash Hg Air Hg Atmospheric contaminants Hg Exhaled air Mg Workplace air Mn SRM 2676c air filter Mn Fly ash Ni Airborne particulates and coal fly ash AF;CV;G AA;CV;G AA;CV;G AA;F air-C2H2;L MS;ICPL AA;-;L AA;ETA;L Ni Ni P Pb Pb 931558 9314023 931558 9311057 9311 21 6 Workroom air AA;ETA;G AEICP;G AA;ETA;- Air particulates Air particulates collected on cellulose filters. See As ref.931558 Influence of anthropogenic sources estimated Workroom air AA;ETA;G MS;ICP;L AE;ICP;G Particulate emission Workplace air Isotope ratios used to determine source of Pb in Method allows 0.01 mg Pb per m3 of air to be particulates determined. No interferences from other substances in air See Cd ref. 93/C1300 See Cd ref. 93/2390 Review of GC-AAS determination of organolead See Ni ref. 9314023 Dust from streets collected. Pb levels highest for Emission of Pt in automotive catalyst exhaust See Ni ref. 93/C144 compounds main streets determined under different catalyst conditions AA;F;- SRM 2676c air filter Atmospheric aerosols Air MS;ICP;L AA;-;L AA;-;G Pb Pb Pb 93/c 1300 9313988 9312390 AA;ETA;- AA;-;- Pb Pb Air particulates Dust 9314023 9314104 Pt Au tom0 tive catalyst exhaust MS;ICP;- 93lC1344 Sb Airborne particulates and coal fly ash NIST SRM coal fly ash Workroom air NIST SRM coal fly ash Workplace air AA;ETA;L 93lC144 Sb Sb AE;Hy 1CP;L AA;ETA;- AE;ICP;- AE;ICP Hy;L AA;F;- See As ref.93JC240 See As ref. 931558 93/c240 931558 Se Se See As ref. 93lC240 Method allows 0.035 mg Se per m3 of air to be determined. No interferences from other substances in air agreed with certified values Mercury-palladium chemical modifier used. Results See As ref. 9313207 93lC240 9311217 Se Se Sn Coal fly ash AA;ETA;L 9312134 9313207 931327 1 Cloud aerosol NAA;-;- AA;-;L AA;- Hy;- Indoor air Determination of organotin substances after improper use of fungicide in office. Samples collected in absorbers containing HNO filtered and mineralized in an autoclave at 160 "C Palladium acetate used as chemical modifier.Good agreement with spiked recovery results and SRM values (0.66 ng) See Ni ref. 93/C144 Ti Coal fly ash AA;ET&- AA;ETA;L A A; ETA;L 9313466 V V Airborne particulates and Coal fly ash coal fly ash 93lC144 9313464 Separation of V using monothio-P-diketo liquid chelating exchanger in formaldehyde medium. Good agreement with spiked recovery results and SRM values (0.55 ng) See Cd ref. 93/C1300 See Cr ref. 93/1858 See Cd ref. 9312390 Slurry homogeneity achieved with an automated sample introduction system which includes ultrasonic probe for mixing. Transversely heated graphite atomizer investigated Coal briquettes emitted fewer pollutants than raw coal when burnt in industrial boilers Zn Zn Zn Various SRM 2676c air filter Air Atmospheric aerosols Coal fly ash MS;ICP;L XRF;-;S AA-;L AA;ETA; S1 93/c1300 931c115 9311858 9312390 Various Coal-fired plant emissions AA;-;- 931572JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 29 R Table 1 (continued) Technique; atomization; analyte form* AA;-;- AA;ETA;L EIement Various Various (8) Various Various Various Various (10) Various Various Various Various Various (38) Various Various Various Various (> 40) Various Various Various Various (24) Various Various Various (14) Matrix Airborne particulates Urban air particulates Sample treatment/commentsT Review of trace element analysis of air samples Sample collected on membrane filter and dissolved with HN03 + H,O in a Teflon bomb. Platform atomization used.Results agreed with CRM values Chemical characterization of particles gives more information on their toxicity Effect of varying thickness and sample composition meant standard matrix correction procedures could not be applied. A relevant correction equation was determined from experimental data. Results correlated with those from ICP-MS and AAS atomizer collection and handling. Ultrapure HCl or HNO (0.1 to 0.4% v/v) used for preservation acid mixture. Boric acid caused matrix effects and increased detection limits Sample collected on filter paper. Speciation performed by pre-treatment by water- and acid-leaching Review of HG in atomic spectrometry for analysing air samples Sample collected on glass fibre filters. Contamination on blank filter reduced number of elements that could be determined Characterization of volcanic aerosol from Kilavea volcano in Hawaii Plume simulating dilution sampler used to collect particulate samples.Data used to assess impact of stack emissions on Grand Canyon qualitatively by XRF used for characterizing particles Electrostatic precipitation directly into a graphite Low levels of metals in precipitation require clean Microwave digestion using aqua regia + HF + boric Heavy metals determined quantitatively by AE and Review of micro- and surface-analytical techniques Reference 931625 931729 931C910 93/C980 9 3/C9 87 9311055 93/1068 9311151 931C1618 9311682 93/1843 9311890 931201 1 9312223 93/2229 9312746 93/2819 9 3/28 1 9 9312939 931C3036 9313345 9313409 Workroom air Environmental dust AE;ICP;- XRF;-;S MS;ICP;- AA,-;- Atmosphere Atmospheric precipitation AA;ETA;G AE;ICP;L MS;ICP;L NIST SRM 1633a coal fly ash Ocean aerosols Air pollutants Aerosol particles AE;ICP;L AA;ETA;L AA;- Hy;- XRF;-:S Volcanic aerosol Coal fly ash XRF;-;S XRF;-;S Fly ash Environmental particles AE;-;- XRF;-;- M $laser micropro be;- MS;-;- MS;ICP;L Atmospheric particles Fly ash Fly ash Dissolution with mixed acids in high pressure Teflon Different X-ray emission methods tested including PC based software accounts for inter-element effects. bomb synchrotron radiation XRF Matrix corrected values agree well with wet chemistry data Viability of GDMS for full chemical characterization of fly ash tested using CRM samples.Results gave 20-30% accuracy and ppb-ppm limits ID spark source MS used ( 10-10-4 pg mP3) XRF;-;- XRF;-;- Coal fly ash MS;GD;- MS; spark source;- MS;ICP;- FANES;-;- Atmospheric dust Airborne particulates Tube of porous graphite used as filter for airborne particulates.Tube then coupled directly to furnace atomic non-thermal excitation spectrometry for analysis Sampling method and sample digestion techniques prior to ICP-AES discussed and results compared with those from INAA Samples collected with Berner impactor. Dissolution using two or three 20 min periods with 0.2 mol I-' HNO in polystyrene tubes in an ultrasonic bath at 50°C Multiple regression of data allowed source apportionment of aerosol samples from industrialized region of Bombay and Fe whereas traffic dust was high in Br and Pb Industrial dust showed elevated levels of As Co Cr Atmospheric particulates AE;ICP;L NAA;-;- Atmospheric aerosols AA;ETA,L Various Bombay aerosol 93 f3521 AEiICPi- EDXRFi-i- 93/3708 Various (40) Roadside dust P4AAi-i- AE;ICP;- AA-;- XRF;-;S Various Environmental dust Dust samples of about 0.07 g fused with lithium fluoride-lithium tetraborate to yield homogeneous micro bead Potentially toxic elements given particular attention Acid dissolution in a microwave oven prior to ICP- AES.Comparison of results from all methods indicated caution required before accepting results from any method 93/3807 93/3823 9313899 Various Particulates Various Coal fly ash EDXRF;-;- AE;ICP;L XRF;-;S NAA;-;-30 R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 Table 1 (continued) Technique; atomization; Element Matrix analyte form* Sample treatmentlcommentst Reference Various Street dust AA;F;- Certain elements found to be high in vicinity of 9314004 Various Respirable dust EDXRF;-;S Dust recovered from membrane filters by dissolution 931407 1 varying activities AA;-;- in benzene AE;ICP- Various Atmospheric aerosols NAA;-;- Review of multi-element analytical methods for 9314106 AE;-;- analysis AA;ETA,F;- * Hy indicates hydride and S L G and Sl signify solid liquid gaseous or slurry sample introduction respectively.Other abbreviations are t Values in parentheses are detection limits. listed elsewhere. The benefits of on-line analysis are highlighted by de Loos- Vollebregt and Koot (93/C106) who found that flow injection hydride generation AAS gave lower matrix element interferences compared with a batch hydride method.They achieved recov- ery of 100% and precision of 3% for the determination of As in a fly ash CRM. An on-line reduction and HG method has been combined with conventional ICP nebulization (93/C240). This has allowed As Sb and Se to be determined simul- taneously with other elements but at a sufficiently low level to meet the requirements of the US Environmental Protection Agency. The usefulness and limitations of HG in atomic spectrometry for determining the hydride forming elements in environmental samples have been discussed (93/C168). A method for monitoring the reduction of Cr(vr) during sample collection has been described (93/2253). Quartz fibre filters were spiked with an isotopically enriched chromate salt and used to collect emission particulates from a waste water sludge incinerator. After sampling the Cr(v1) was extracted from the filters with 0.1 mol 1-1 NaOH. The ratio of enriched Cr(v1) to native Cr(v1) emitted from the incinerator was determined by ICP-MS following preconcentration by ion chromatography.The reduction of Cr(v1) was calculated using a pseudo-first order reaction model. 1.2. Instrumental Analysis The production of similar atomization profiles for Ga in slurries of fly ash and in aqueous standards was achieved by Shan et al. (93/1028) when they used a nickel modifier and electrothermal atomization. In the presence of the nickel modi- fier the integrated absorbance value for Ga was improved by a factor of 2.46 and matrix interferences with the absorption signal were eliminated.Following calibration with aqueous standards the data obtained from analysis of fly ash slurries agreed well with certified values. In general Hg is determined by CVAAS but Welz et al. (93/412) have devised a method for determining this element by ETAAS using palladium nitrate- magnesium nitrate modifier. They found that a single addition of 15 pg of palladium was sufficient for 40-60 determinations of Hg if the graphite tube was not heated to greater than 1500°C. It was possible to use a pyrolysis temperature of 400°C without any loss of Hg. Interference from sodium chloride was overcome by using 95% argon and 5% hydrogen as a purge gas. Stuckenberg and Rademeyer (93/C980) found that variations in mass and composition of environmental dust samples col- lected on filters caused unacceptable errors when the filters were analysed by X-ray fluorescence spectrometry.Standard matrix correction procedures could not be applied because the samples were not of infinite thickness. A correction formula was devised which allowed for the variability in thickness and composition. The elemental concentrations obtained using this correction correlated well with those obtained by ICP-MS and AAS. A method for the rapid characterization of fly ash by XRF with the use of PC-based software to correct for inter- element effects has been also described by Mishra et al. (93/28 19). Mass spectrometry has been employed in a variety of studies to monitor isotopes of C. The monitoring of I4C emitted from nuclear power stations became possible when accelerator MS was used (93/2535).Conventional radiation monitoring for 14C proved problematic because it is a pure p-emitter and also the ventilation air emitted from the stacks contained much higher activity concentrations of noble gases and activation products. Accelerator MS was also used to monitor 14C0 which proved a more sensitive indicator of OH abundance than the longer lived trace gases normally used (93/2648). The expiration of 13C02 following administration of 13C labelled substrate to subjects during clinical and metabolic studies was facilitated by the use of GC isotope ratio MS (93/2318) and quadrupole MS (93/3593) respectively. 2. WATER ANALYSIS As in many areas of analytical science the trend in water analysis is for more elements to be sought at lower concen- trations and Table2 demonstrates that ICP-MS is now in routine use for this purpose.However sampling techniques may be a serious constraint in ultra-trace analysis and it is instructive therefore to consider the problems associated with the collection and analysis of ice and snow samples for the determination of very low levels of heavy metals (93/2140). Stringent precautions were required to obtain representative data from ice cores from depths down to 2.5 km. Values for Pb and Zn were found to vary by three orders of magnitude from the surface to the centre of the ice cores because of the necessity of using metal drills at these depths. There are still relatively few aqueous reference materials available.Therefore the preparation of two new freshwater RMs by the Community Bureau of Reference CRM 398 and CRM 399 certified for Al Ca C1 Fe K Mg Mn Na P and S is welcomed (93/1127). 2.1. Sample Preparation 2.1.1. Microwave digestion One of the basic considerations when collecting water samples is whether the application requires quantification of the total elemental content including particulates the ‘dissolved’ frac- tion or specific species. There is an increasing use of microwaveJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 31 R sample digestion for water samples where a total content is required. Microwave heating has been shown to be a viable alternative to the conventional open beaker hot-plate method for the determination of the metal content of domestic and industrial waste waters by DCP-AES (93/3278).This approach was also adopted for the preparation of surface waters prior to their analysis by AAS and ETAAS (93/C898). A sophisticated approach to on-line sample microwave pre- treatment is described in a series of papers by Tsalev and co-workers (93/2717 93/2718). Liquid samples were pre- treated in a microwave oven incorporated as part of a FI-HG and CVAAS system. Oxidation was effected by a combination of bromination and peroxodisulfate and conditions optimized for the measurement of As Bi Pb and Sn in waters. Savage et al. (93/C90) also determined Hg in waste waters with on-line microwave digestion coupled to a continuous flow CV gener- ation unit. 2.1.2. Chelating resins There has been considerable interest in the use of 8-hydroxyquinoline (8-HQ) to separate and preconcentrate a variety of metals (93/C14 93/1017 93/C1471 93/C1634 93/2055 93/3372).A Canadian group with considerable experience in the application of this technique to the determi- nation of metals in sea-water by ICP-MS (93/2055) has also developed a microscale preconcentration system for use with ETAAS (93/C1471 93/3372). Trace metals were chelated on a 20 p1 column of silica-immobilized 8-HQ and then eluted directly into the furnace in 48 pl of acid. Enhanced sensitivities of up to 250-fold over direct injection for Cd Cu Fe Mn Ni Pb and Zn in sea-water were reported. An on-line system for the determination of A1 by flame AAS using 8-HQ immobilized on controlled-pore glass has also been described (93/C14 93/1017).An enrichment factor of 76 was achieved with a detection limit of 3 ngml-l; the method was successfully applied to river and sea-waters. Speciation of Cr has also been achieved using 8-HQ (93/C1634). Chelating agents have been used in conjunction with acti- vated carbon (93/C312). After treatment of the water sample with the chelating agent and activated carbon the carbon was removed by filtration made into a slurry and injected into a graphite furnace for analysis by AA; preconcentration factors of up to 400 were claimed. Other chelating agents are given in Table 2 including a new type of chelating resin carboxymethyl- ated pol ye thylenimine-polymethylene-polyphenylene isocyan- ate which was used to preconcentrate Zn from sea-water prior to determination by ICP-AFS (93/3944).Methods to detect Pd Pt and Rh in waters are not common. A conference paper by Lee et al. (93/C3032) describes the preconcentration of these elements as their bis(carboxylmethy1)-dithiocarbamate chelates. After absorbing the complexes on XAD-4 and elution detection limits of 0.03 0.1 and 0.01 ng ml-' respectively were obtained by ETAAS (93/C3032). 2.1.3. lon-exchange resins A number of studies employing ion-exchangers are given in Table 2. The most novel polymeric support reported this year was the residue from the production of cider which was chemically modified to improve its performance (93/11 10). Small packed beds filled with apple residues were used to preconcentrate heavy metals from sea-water; the metals were eluted with HCI and determined by AAS.Burba and Bloedorn (93/3783) compared the performance of the cellulose-based ion exchangers EDTrA HYPHAN and TETPA for multi-element preconcentration from waters both off-and on-line prior to analysis by ICP-AES and AAS. Their conclusions were that the suitability was EDTrA = TETPA > HYPHAN but the presence of complexing agents such as humic substances or high dissolved solids content reduced the recovery for many elements. 2.1.4. Solid sorbants The trend towards smaller and more automated preconcen- tration systems continues with flow injection systems com- monly combined with columns of various descriptions to achieve this aim. Welz (93/482) has reviewed recent progress in on-line preconcentration of trace elements for AAS and ETAAS using solid sorbants (33 refs.).Enrichment factors of 20-25 can be achieved using a 20 s loading time which makes the throughput comparable to that in routine AAS. When such a system is combined with ETAAS an additional advan- tage conferred is the separation of the determinand from the matrix elements which is particularly important for more saline matrices. Speciation can also be carried out under the appropriate reaction conditions; an example is the separation of Cr species using activated alumina with AAS detection (93/2896). In China xanthate cotton and suvhydryl cotton jibres are frequently employed for preconcentration of metals but they do not seem to have achieved the same popularity elsewhere (93/502 93/654 93/2150 93/4016).One exception is with Gomez and MacLeod ( J . Anal. At. Spectrorn. 1993 8 461) who used sulfhydryl cotton to preconcentrate Au from natural waters using mini-columns and on-line FI introduction of the sample in ICP-AES. One advantage of these types of columns is that they can also be used to isolate individual species of elements such as Cr or Hg in the field thus avoiding the problems of preservation and transport of liquid samples (93/C8). 2.1.5. Solvent extraction Of the methods reported employing a solvent extraction step (see Table 2) one of the more ambitious was the determination of Bi at ng 1-l levels in sea-water. This was accomplished by extracting the Bi-DDC complex into xylene and back- extraction into 100 pl of HN03 prior to determination using ETAAS (93/2722).The authors claimed a detection limit of 0.27 ng I-' based on a 3300-fold concentration factor. A method of rapidly determining metals in coastal sea-waters has been proposed by Apte and Gunn (93/C37). They extracted metal-APDC complexes into a small volume of l,l,l-trichloroethane and directly injected an aliquot of the organic extract into an ETAAS furnace. One of the few examples of the use of solvent extraction in combination with ICP-AES was provided by Miyazaki et at. (93/1205). Thallium was extracted into 2,6-dimethylheptan-4- one after complexation with APDC and hexahydro-1H-azepin- ium hexahydro- 1H-azepine- 1-carbodithioate and determined directly by ICP-AES. The reported detection limit was 1.3 ngml-I TI for a 160ml sample although the 190.86nm line suffered from an increase in background intensity thought to arise from carbon in the solvent.2.1.6. Precipitation and Potation techniques It would appear from the relatively few papers published on precipitation techniques that most of the activity in this area is in Japan. Coprecipitation using Zn-DDC was studied for the determination of trace amounts of CrV' in river water and sea- water by ETAAS (93/4077). The detection limit for CrV1 was 0.014 pg and the method was not influenced by the presence of Cr"'. Ytterbium was determined in sea-water by ETAAS after coprecipitation with Fe(OH) (93/546 93/1178). Traces of A1 were measured by ETAAS after preconcentration of A1 with benzyldimethyltetradecylammonium ions; A1 was then eluted with a mixture of C2H,0H and N,N-dimethylformamide (93/578). This method was applied to the analysis of tap water.Namkashima (93/3956) has examined conditions for the simul- taneous extraction of Bi and Sn from sea-water by coprecipi- tation of these metals with thionalide at pH 2-3. The precipitate was then floated with the aid of a surfactant and N recovered,32 R Table 2. JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 SUMMARY OF WATER ANALYSES Technique; atomization; analyte form* AA;ETA;L Sample treatment/commentst Preconcentration on carbon after complexation with dithiophosphoric acid 0,O-diethyl ester (ammonium salt) (0.3 pg ml-') Preconcentration using flotation method; HCI-KI used to concentrate Ag and Au using cetyl pyridine bromide as collector and IBMK as extraction solvent (0.2 ng m1-I) Preconcentration using Chelex-100 at pH 6.5 in CH,COONa (0.1 mol 1-') followed by elution with 1 rnol I-' HNO optimization of operating conditions ammonium ion complex on a PTFE membrane; elution with 5 ml of a mixture of C,H,OH and N,N-dimeth ylformamide 8-hydroxyquinoline on controlled-pore glass in a buffer of 0.1 mol 1-' malonate at pH 10 (3 ng ml-') Speciation study using Fleitmann reaction for arsine generation followed by in situ preconcentration in furnace (0.1 pg ml - ' ) Assessment of arsenic in surface and well waters in central Arizona USA (12-120 ng ml-I) Automated method for HG following separation of As species by HPLC; determination of arsenite arsenate monomethylarsonic acid dimethylarsinic acid arsenobetaine and arsenocholine sample at pH 3 and pH adjusted to 6-7.7 with NaOH; 1 ml of sodium dodecyl sulfate-sodium oleate added.Material containing As"' floated by N,; filtered dissolved in acetone evaporated to dryness and residue digested with HNO and HC104; digest dissolved in HCI diluted and treated with KI prior to determination coprecipitation liquid-liquid extraction and adsorption on activated carbon chromatography and continuous generation for As"' and AsV (0.5-4.6 pg ml-l) Simultaneous determination of As Sb and Se using batch generation; reduction using NaBH (1.5 On-line preconcentration using microcolumns of Evaluation of Pd-Mg( Preconcentration of a benzyldimethyltetradecyl- as chemical modifier; On-line preconcentration using immobilized 10 ml of 2% thionalide in acetone added to 1 1 Evaluation of different preconcentration techniques On-line FI system using ion-exclusion Pg*ml- '1 Amberlyst A-26 or sulfhydryl cotton; deposition/elution conditions outlined.Amberlyst A-26 retained Au under acid conditions with elution with NH,OH (2 moll-') whereas with sulfhydryl cotton Au retained in neutral media with elution with KCN (ng ml-l) See Ag ref. 93/1284 (1.0 ng ml-') Preconcentration using tributylphosphate onto a solid extractant followed by back extraction with thiourea (0.2 pg ml-') On-line chelation ion-exchange chromatography using a microcolumn; 400-fold enhancement factors reported Extraction using ion-exchange chromatography Application of B isotopes for identifying contaminants in ground water; study of fly ash leachate in ground water Isotopic compositions of B in brine sediments and source water in Da Qaidam Lake Quinghai China determined Flow injection sample-to-standard addition method; internal standardization compensates for matrix suppression in high salt containing samples (5-200 ng ml - ') Solvent extraction using triisooctylamine in heptane and 1 1 of sea-water at pH 1.5 followed by back- extraction with HNO (14 mol dm-3); optimum Reference 93/c142 9311284 931454 931480 931578 9311 0 17 93/C134 93/C387 9311 141 9312180 Element Matrix Ag Sea-water Ag Waste water AA;-;L A1 Haemodialysis water AA;-;L AA;ETA;L AA;ETA;L A1 Water A1 Tap water A1 River and sea-water AA,F N,O-C,H,;L As River water AA;ETA Hy;L AA;ETA;L AA;- Hy;L As Natural water As Sea-water As Sea-water AA;- Hy;L As As As Au Natural water Geothermal water Natural water Process and natural waters XRF;-;L AA;- Hy;L MS;ICP Hy;L AE;ICP;L MS;ICP;L 9 312 7 56 9313096 9313387 93JC27 AA;-;L INAA;-;L XRF;-;L AA;FL MS;-;L -_ ; ;L TIMS;-;L MS;ICP;L Au Au Waste water Water 9311284 93/1666 Waste water AU 93fC3061 B B Water Ground water 9312342 9312937 B Natural water 9313099 Sea-wa ter Ba 93/C1526 Bi Sea-water MS;ICP;L 931104033 R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Table 2. (continued) Technique; atomization; Element Matrix analyte form* Bi Water AA;F;L Sample treatment/commentst Reference 9312197 Solvent extraction using 2,4,6-tri-( 2-pyridyl)-1,3,5- triazine and Clod-; complex extracted into nitrobenzene (pH 2.0-3.5) followed by direct determination (5 ng ml-l) Solvent extraction of dithiocarbamate complex into xylene followed by back-extraction into 100 pl HNO,; 25 000-fold increase in concentration (0.27 9312722 Pg m1-7 Preconcentration using thionalide complexes of Bi and Sn floated with the aid of a surfactant and N bubbles; precipitate filtered dissolved in acetone and digested with HNO and HCIO,.See also As ref. 9312180 On-line generation of volatile Br by oxidation of aqueous bromide with 100 mmol I-' K2S208 in 5.0 mol 1-1 H,SO,; good agreement of results with those obtained by ion chromatography and ICP- MS controlled water-jacketed vessel containing 0.3 ml H3P04 and a magnetic spinbar; vessel connected directly to MS inlet. Evolved CO drawn through two -90 "C traps to separate water vapour and C02 condensed into a liquid nitrogen trap Coprecipitation with Zr(OH)2; sample pH adjusted to alkaline with aqueous NH 20 pg Zr added and mixture filtered. Filtrate dissolved in 0.25 pg ml-' La prior to analysis acid + HNO was determined to be optimum.Comparison with results obtained by polarography and analysis of reference standards analysis of two sea-water NRCC CRMs (CASS-1 and CASS-2) (15 pg m1-l) 93 f3956 931585 Sample injected into an evacuated temperature 9312247 Study of organic chemical modifiers; tartaric Direct determination using NaOH as modifier; Preconcentration using sulfhydryl cotton fibre Solvent extraction of diethyldithiocarbamate complex with benzene at pH 5.5 Samples sprayed onto Mylar or Kapton film using a nebulizer; detector used consisted of a 7 mm thick 79 mm2 pure Ge crystal with a cryogenic preamplifier Monitoring of Swiss nuclear power plants for 36Cl; comparison with liquid scintillation counting Indirect determination based on reaction of CN- with Hg' (22 pg) Aqueous calibration quadline background correction Atomization from a W coil in an atmosphere of 90% Ar and 10% H (4.0 pg) Preconcentration and separation of Crrrr and Cr"; sample solution mixed with HCl and extracted with tri-n-butylphosphate (TBP) for determination of Cr".Cr"' extracted by the addition of buffer (CH,COOH + CH,COONa) and KSCN to sample solution followed by extraction with TBP Investigation into enhancing effect from sea-water matrix on Cr signal; ascorbic acid triaminecitrate and tartaric acid evaluated.Mixture of ascorbic and triaminecitrate most effective. Accuracy assessed by analysis of RMs (0.11 ng ml-') Speciation of Cr"' and CrV' reported; Cr"' chelated using 8-hydroxyquinoline (0.1 mol dm- in CH,OH) into IBMK. Effects of pH extraction and heating time amounts of reagents for extraction sensitivity accuracy and precision studied. Total Cr determined using a range of chemical modifiers including HNO Mg( NO3) and Na2W0,; Mg(NO,) determined to be the best (39 pg ml-') Speciation of Cr using FI on-line preconcentration with selective adsorption on activated alumina; sequential species-selective sorption possible using the Clark-Lubs buffer systems with pH 7 for Cr"' and pH 2 for CrV' 93 fC1634 Bi Sea-water AA ETA; L Bi Sea-water Br Sea-water AE;MIP;L C (dissolved Water inorganic) MS;-;L Ca Cd Water Sea-water AA;F;L AA;ETA;L 9312 1 9 1 93/719 Cd Sea-water A A; ETA; L 9312727 Cd Cd 9 3/40 16 9314058 River water Water c1- Natural water XRF;-;L 9312397 c1 Reactor cooler water Accelerator MS;- AA;cold vapour;L ;L 9312389 931657 CN Water 9 3/C46 93/C164 Cr Cr Sea-water Water AA;ETA;L A A;ETA;L 93/C950 Cr Surface water AA;-;L Cr Sea-water A A;ETA;L 9311227 Cr Mineral water AA;ETAL AA;F;L 9312896 Cr Water34R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Table 2. (continued) Technique; atomization; Element Matrix analyte form* Cr Natural water MS;ICP;L Sample treatmentlcommentsf Study of polyatomic interference at m/z 52; interference from 40Ar'2C due to presence of inorganic carbon in sample.Interference correction factor incorporated after measuring I3C and extracted into IBMK; effects of pH extraction and heating time and amounts of reagents required studied (12 pg ml-I). Modifiers for total Cr studied [HN03 Mg(N03)z and Na,W04]; preconcentration with hot injection using Mg( N03)2 optimized (29 pg ml- ') Study of electrodeposition for Cr speciation; voltammetric behaviour of CrV' and Cr"' at pH 4.7 on a glassy carbon electrode studied. The use of L'Vov platform as a cathodic electrode for the selective preconcentration of Cr species on a mercury film also studied. The latter method preferred (0.15 ng ml- ') Review of Cr determination; sample pre-treatment instrumentation and analysis discussed Coprecipitation using zinc-diethyldithiocarbamate complex at pH 3.5; precipitate collected on a membrane filter and dissolved in ethyl acetate Cr"' chelated with 8-hydroxyquinoline in CH30H (0.014 clg) Study of long-lived radionuclide behaviour in the zone affected by the Chernobyl accident; speciation of ?Sr and 137Cs determined.Migration of species described by a convective-dispersive equation; adsorption controlled by the cation-exchange capacity and the cationic composition of the liquid phase Preconcentration using N,N-diethyldithiocarbamate complex; collection onto cellulose nitrate membrane filter. Complex and filter dissolved into N,N-dieth ylformamide Preconcentration using an Amberlite IR-120 column; speciation of total Cu free Cu inorganic Cu and organic complexes were determined (2.84 ng ml- l) Effect of organic compounds in sea-water investigated; Cu suppression eliminated.Comparison of results with FAAS method incorporating preconcentration step Preconcentration using xanthate cotton; 0.2 g xanthate cotton mixed with 1 ml HCI and 0.5 ml of 1 + 1 HNO and boiled for 5 min reported studies; water removed by condenser and H2S04 as dessicator (8 ng ml- ') Levels of Cu in drinking water of Madrid Spain Ultrasonic nebulization into MIP source for AA See Cd ref. 9314016 See Cd ref. 9314058 Solvent extraction of complex with salicylaldehyde Preconcentration using a trioctylphosphine oxide guanylhydrazone into IBMK chemically modified W-electrode; electrode placed in graphite cup prior to determination Flow injection with in situ concentration of hydride; Pd coated graphite furnace used to trap hydride at 600 "C prior to atomization at 2500 "C from 36 ions studied (15 pg ml-') subsequent trapping and atomization in a pre- coated Pd furnace (0.004-0.03 ng ml-') On-line pre-treatment using H,SO prior to reduction with SnCl and phase separation.Quantitative recovery of spikes of organo-mercury compounds On-line microwave dissolution; optimization of parameters Preconcentration on a solid support and elution with toluene; determinand butylated using a Grignard reagent and separated by directly coupled GC prior to detection Preconcentration using tannic cellulose; interference Preconcentration using an FI-HG system with Reference 931308 1 93/323 8 Cr Water AA;ETA;L Cr Water AA;ETA;L 93/3243 AA;ETA;L AA;F;L AA;ETAL 9314024 9314077 Cr Cr Natural water Natural water c s Natural water 93/410 AAETA;L c u Natural water 931560 c u AA;-;L Water 93/866 c u Sea-water A A;ETA;L 9311225 c u Water AAF;L 93/2150 c u c u Drinking water Water AA;-;L AA;MIP;L 9313265 9313550 c u c u Fe River water Water River water 9314016 93f 4058 9311230 Ga Water AA;ETA;L 931688 Ge Water AA;ETA Hy;L 931c153 Ge Ge Ground water Water AE;ICP Hy;L AA;ETA Hy;L 9313128 93/3227 AA;cold vapour:L Natural water 93/C64 Water Water AA;cold vapour;L 93/c90 93/c101 AEMIP;L AA;quartz ce1l;LJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Table 2. (continued) 35 R Technique atomization; analyte form* AA;cold vapour;L Element Matrix Hg Sea-water Sample treatmenticomments't Survey of Baltic and North Sea waters; preconcentration on Au and a new sampling system (MERCOS PTFE water samplers) evaluated (0.5 pg ml-') Solvent extraction of APDC complex into CHCI (0.1 ng m l ~ ' ) Solvent extraction using dithizone into IBMK followed by reduction to Hg' using SnCI Preconcentration using xanthate cotton ion-exchange fibres followed by elution with a HCI-NaCI solution prior to reduction to Hg' with NaBH (5.15 ng m l - ' ) conventional pneumatic nebulizer; memory effects reduced Results of collaborative tests using method DIN 38 406 reported Preconcentration using a single-stage gold amalgamation (1 pg) Application of a surfatron microwave source (0.02 ng 1 Continuous flow cold vapour generation using SnC1 Evaluation of system including use of microwave On-line microwave sample pre-treatment designed Preconcentration using ion-exchange resin for 12sI; Comparison of direct injection nebulizer with as reductant (0.04 ng ml- ' ) dissolution and evaluated (10 pg ml-') study of rivers throughout Britain.Non-detectable or low amounts were found in most rivers Rivers Trent Cam and Thames ranged from 1-100 mBq I - ' Continuous flow gas-phase sample introduction; 1 0 - reduced to I- with ascorbic acid and I generated using 1 mmol I - ' NaNO in 5 mol 1-' H2S04 Monitoring at 183.04 and 206.16 nm gave results in agreement with ICP-AES data Solvent extraction of thenoyltrifluoroacetone complex with tributylphosphate (1 ng ml-') Speciation of Mn" and Mn" by membrane separation (0.22 pm) (0.2 ng ml- ' ) Solvent extraction using Cryptand 221 with erythrosin (as counter ion) into CHCI, separation from Cd Co Fe Ni Pb T1 and Zn Sample mixed with 2 mol I - ' acetate buffer adjusted to pH 6.4-7.4 with 0.2 mol I - ' NaOH and shaken for 2 h with Spheron Oxin 1000; adsorbent filtered dried at room temperature and heated at 60 -C under reflux in 1 mol I - ' HNO,.Mixture filtered and filtrate analysed using 279.5 nm line (5.0 pg ml- ') phenyl-2-furylacrylohydroxamic acid and trioctylmethylammonium cation into IBMK (ng mI - ) Preconcentration using a macroreticular poly(dithi0carbamate) resin (0.5 ng ml- ' ) Matrix modifiers evaluated Pd-Mg( NO,) Pd -HONH,Cl BaF and LaCI,; preconcentration on the graphite tube was required. Optimum performance was obtained using BaF (24 Solvent extraction of N - P6 m! -.') Coprecipitation with cobalt-dithiocarbamate ( 0.5 Solvent extraction using ng rnl-') 5-nitrosalicylaldehyde-4-phenyl-3-thiosemicarbazone at pH 8.0-8.7 into IBMK for 30 min direct aspiration into flame (0.2 pg) Preconcentration using HPLC followed by reduction using the Dumas method to N prior to analysis.Results from deep ice-core analyses from Dome Summit Greenland reported Reference 93 4x4 93 666 93 iC960 93 1239 93/21 63 93 2677 9313229 93 3281 9313492 93 3714 93 3924 93 1717 Water Water Water AA;cold vapour;L AA;cold vapour;L AF;cold vapour;L Drinking water MS;I C P;L Waste water Natural water Water Waste water Natural water Water Drinking water AA;cold vapour:L AF;cold vapour;L AE;MIP;L AE;MIP cold vapour;L AF;cold vapour;L AA;cold vapour;L XRF;-;L I Sea-water and brine A E;M I P;L 93 2123 Li Mn Mn Water Natural water Natural water AE;F;L AA;ETA;L AA;F air-C,H,;L 93,'4099 93 /C 140 931557 931857 Mn Potable water AA;F C,H,-air;L Mn Natural water AA;-;L 9311231 93 3970 93,C 1635 Mn Mo Natural water Water AA;F;L AA;ETA;L AE;ICP;L AA;F air-C,H,;L 93 13 105 9 3!4079 Mo Ni Water Sea-water 9312941 NO,- Ice MS;-;L36R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Table 2. (continued) Technique; atomization; analyte form* Sample treatment/commentsf Conversion to PO - followed by coprecipitation with hydrated Fe20 and adsorbed on activated charcoal (0.89 pg g-') Directly coupled reversed-phase HPLC; desolvation using a membrane drier (trimethyllead) Guidelines for optimizing ultrasonic slurry sampling reported; accuracies between 5-10% of CRM values to determination (5-200 ng ml - ') immobilized polyurethane foam and elution with mineral acid; optimum conditions for sorption and desorption evaluated (sorbent capacity pH elution flow rate) plumbing materials; isotope ratios determined by correlation to NIST SRM 981 Speciation of organolead compounds at the sub- pg ml-' level reported solvent extraction of dithiocarbamate complexes of ionic organolead species into hexane followed by propylation using a Grignard reagent (0.1 pg ml-') Determination of tetraethyllead formed by reaction with tetraethylborate followed by GC separation (0.3 ng g-') diethyldithiocarbamate complexes prior to GC separation (0.1 pg ml-') Determination of Pb sources in plumbing materials and tap water; Cu pipe or solder was primary source.See also 93/C1484 Preconcentration using sulfhydryl cotton fibre prior Preconcentration using xanthate cotton at pH 6.0 Preconcentration using diphenylthiocarbazone Identification of sources of Pb in tap water and Ionic organolead species extracted as See Cd ref. 9314016 See Cd ref. 9314058 Preconcentration using ion-exchange chromatography of chelates; bis(carboxylmethy1)- dithiocarbamate chelates formed by addition of 1.2% solution to sample containing 1 mol 1-' HC1 and 0.25% SnCl,. Complexes adsorbed on XAD-4 prior to elution counter directionally using NH40H (0.03 ng ml-') See Au ref. 931C3061 See Pd Ref. 931C3032 (0.1 ng ml-l) Reference 9312758 93/c57 93/Clll 931502 931654 93/c902 93/c 1484 9312069 Element Matrix P Waste water XRF;-;L Pb Natural water MS;ICP;L Pb AA;ETA;L Pb Water Pb Water AA;F air-C2H2 quartz tube;L AA;F;L Pb Surface Water AA;F;L Pb Pb Tap water Tap water and snow MS;ICP;L AE;MIPL Pb Water MS;-;L 9312424 AE;MIP;L Pb Natural water 9313117 Pb Potable water MS;ICP;L 9313617 Pb Pb Pd River water Water Water _- ; ;L AA;ETA;L AE;ICP;L AA;ETA;L 9314016 9314058 93jC3032 Pd Pt Waste water Water AA;F;L AE;ICPL MS;ICP;L MS;ICP;L AA;ETA;L 93lC3061 931c3032 Pt Ra Water Drinking water FI system using ID for calibration Comparison with alpha spectrometry for 226Ra determination; ion exchange sample clean-up required prior to detection (1 fg ml-') Optimum conditions obtained for analysis; interferences investigated (0.03 ng ml-') On-line preconcentration using anion exchange chromatography prior to elution with HNO,; Lu as an internal standard or ID were used for calibration (0.27-0.1 pg ml-') Depth profile of Re in the Pacific Ocean reported using ID and negative-ion TIMS Preconcentration using anion chromatography of ReO,-; see also Pt ref.9313442 See Pd ref. 93lC3032 (0.01 ng ml-') 9313442 931C1583 AA;ETAL MS;ICP;L Rb Re Natural water Sea-water 9311204 931 2319 Re Re Rh S2 - Sea-water Water Water Waste water TIMS;-;L 9313101 9313442 931c3032 931481 MS;ICP;L AE;ICP;L Molecular A A;ETA;L emission;F N,-H,;L Liberated H2S by acidifcation of samples with 3 mol 1-' HC1 monitored in a cool flame by molecular emission at 384 nm; automation allows 20 samples h-' to be monitored (0.026 pg ml-') Energy dispersive XRF used; precipitation of S2- as ZnS See As ref.93/3387. APDC replaced I- as the reducing agent due to interference from I- on HG of Se (2.4 pg ml-') using hex-1-ene in toluene; evaluation of selectivity of method Preconcentration of organoselenium compounds S2 - Sb XRF;-;L MS;ICP Hy;L Waste water Natural water 9311870 93j3387 Se Natural and waste water AA;ETA; L AA,F;L INAA;-;L 93/c933JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 37 R Table 2. (contirzurd ) Technique; atomization; analyte formr AA;-- Hy;L Element Matrix Se Water Sample treatment/commentst Reference 93!3090 Preconcentration using a cold trap system; See As ref. 93/3387 (6.3 pg ml-') comparison with dry ashing method using Mg(NO,),+HNO,+HCI ( 2 p g m l - ' ) 93/3387 93,3613 Direct determination of silicate without any sample pre-treatment; comparison with colorimetric analysis On-line HPLC using cyanopropyl-bonded silica columns and tropolone as mobile phase; speciation of butyltin (mono- and dibutyl-tin) compounds as tropolone complexes Reliability of data for tributyltin assessed in round- robin exercise (ten laboratories in six countries) off-shore sample the same sample spiked with an undisclosed quantity of tributyltin (175 pg ml-I) and a sample from a yacht marina.Results indicated inherent difficulties in obtaining good precision ( < 20 pg ml- ' j; Similar results were obtained by AA or GC with flame photometric detection followed by in situ derivatization with sodium tetraethylborate prior to GC separation (0.1 pg m1-I) Determination of tributyltin after formation of hydride using NaBH followed by cryogenic trapping at - 196 "C (3.6 pg ml- ' ) 93i1099 On-line preconcentration using a C column 93,c3033 See Bi ref.9313956 Butyltin determination using coupled GC- AA; volatile hydrides formed using NaBH and simultaneously extracted with CH,CI2 (20 -70 Organotin determination using coupled GC-AE Preconcentration using Amberlite IR-120 followed by Samples introduced into flame using ETV; study of p g m l - ' ) elution with 3% EDTA (1.6 ng ml-I) interferences from alkali and alkaline earth elements. Solvent extraction into 2,6-diniethylheptan-4-one to eliminate interferences (0.043 ng ml-I) azepinium hexahydro-1H-azepine-1-carbodithioate complex into 2,6-dimethyl-4-heptanone ( 1.3 n g m l - ' ) Solvent extraction using APDC and hexahydro-1H- Isotope dilution MS using 233U as the spike Coprecipitation using Fe(OH) followed by dissolution with HCI (2 ml of 8 mol I-'); Extraction with 2,6-dimethylheptan-4-one prior to direct injection (0.62-1.35 pg m1-l) see Yb ref.931546 Sample preparation scheme using ultrasound to decompose organometallic species (0.5 ng ml Preconcentration using carboxymethylated polyethylenimine-pol ymethylenepolyphen ylene isocyanate resin (0.1 ng ml - ) Review of applications including on-line techniques; certification analysis of fresh and saline natural water CRMs Field sampling and FI strategies for speciation studies; new speciation data for Cr and Hg reported glass beads impregnated with 8-hydroxyquinoline; optimization of sample pH and buffer (Al Ga and In) Review of on-line preconcentration-matrix separation techniques; comparison with off-line batch procedures (Bi Sb and Se) 1,l I -trichloroethane; direct injection into furnace.Extraction of 25 samples (plus standards) in 90 min; 20 ml sample volume required. Performance data intercalibration data and use for certifying RMs reported ) On-line preconcentration using a microcolumn of Solvent extraction with APDC into Se Natural water Si Sea-water MS;ICP Hy;L A E;IC P; L Sn Water A A; ETA; L Sn Sea-water AA;-;L 9311 191 s 11 Natural water A E; MIP; L Sn Sea-water AA;Hy quartz ce1l;L 9313308 Sn s I1 Sea-water Sea-water AA;- Hy;L A A;quartz furnace;L 9313956 93 '4033 Sn Sr Water Natural water 9314121 93139x5 AE;MIP;L AA;F;L TI Water Laser enhanced ionization;F air-C,H,;L 9315.59 TI Natural water 93 1205 A E; IC P; L U Natural water Yb Sea-water MS;-;L A A;ETA; L 931 1246 9 3 / 5 4 Yb Nat urdl water Zn Water A A;E TA;L AA;-;L 93 1178 93 3296 Zn Sea- wa ter A F; I CP; L 9 3 I3944 93jC6 Various Natural water MS;ICP;L 931C8 Various Natural water A E;I CP;L M S;1 CP; L Various (3) River and sea-water AA;F;L AE;ICP;L 93,!C14 Various ( 3 ) Surface drinking and sea- waters A A;ETA;L 93C16 93iC37 Various Saline water A A; ETA; L38 R Table 2.(continued) JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 Technique; atomization; Element Matrix analyte form* Various ( 6 ) Drinking water AA;ETA;L AA;F;L Various (8) Lake water Various (5) Sea and tap water Various Natural water Various (4) Drinking water Various Water Various Water Various Water Various Water Various River and sea-water Various (4) Sea-water Various Natural water Various (4) Snow Various (6) Water Various (3) Sea-water Various (8) Natural and waste water Various Sea-water Various (9) Water Various Water Various (10) Sea-water Various (4) Natural water Various Drinking water AA,ETAL AA;F;L AA;- Hy;L AA;-;L A A;ETA; L AAETA Hy;L MS;ICP ETV;L AE;ICP ETV;L AA;ETAL AA;ETA;L AA;ETA;L -_ ; ;L AE;ICP Hy;L AA;F;L AA;ETA;L AA;ETA;Sl AA;ETA;L AE;ICP;L A A;ETA; L AA;-;L AA;F;L AE;ICP;L AA;ETAL AE;ICP;L AE;ICP;L AA;ETA;L AE; furnace atomization non-thermal emission spectrometry;L AE;ICP ETV;L Sample treatment/commentst Reference 93lC130 Assessment of water supply in Maracaibo City 93/c129 Venezuela over a 6 month period; tap water preserved by addition of HNOJ (0.1 mol 1-') and stored at 4°C.Accuracy assessed using NIES RMs (0.515 32.1 0.17 3.0 5.0 and 15.3 pg ml-' for Al Ca Fe K Mg and Na respectively) Assessment of origin transport and distribution of elements in Emboaba Lake Rio Grande do Sul Brazil (As Cd Cr Cu Hg Ni Pb and Zn) On-line FI preconcentration using ion-exchange resins; Cd Cu Fe and Mn with D-152 a weak-acid resin and Cr with D-370 an anion-exchange resin (0.1-0.9 pg ml-' for Cd Cu Fe and Mn and 1 ng ml- ' for Cr) Evaluation of methodologies for determination of metals in suspended matter On-line coupled HG and FI; evaluation of optimum conditions and graphite atomization surface (As Bi Sb and Se) Review of the use of graphite furnaces for sampling and detection 93/C136 9 3/c 14 1 93/c152 93lC158 Application of coherent forward scattering spectrometry for the determination of elements at high concentration (undiluted) operating conditions (0.6 12 and 23 pg for Cd Ni and Pb respectively) Trace metal determination in the suspended materials and groundwaters Simultaneous determination of hydride and non- hydride forming elements; analysis of RMs On-line preconcentration and separation using ion chromatography (Cd Cu Fe and Pb) Extraction on a chelating agent followed by preconcentration onto activated carbon; direct injection of carbon containing slurry Preconcentration using W wire prior to determination (0.01 0.47 0.22 and 0.24 pg g-' for Cd Cu Pb and Zn respectively) and 8-hydroxyquinoline (Cd Cu Fe Mn Ni and Review of existing methodology; alleviation of matrix interferences (0.4 1.5 and 5 pg for Cd Mn and Pb respectively) azo-4-hydroxy-3-arsonobenzene and polystyrene- azo-3-sulfophenol-4 was 12-13 times higher than that of Polyorgs VII (Cd Co Cu Fe Mn Ni Pb and Zn) Review of FI on-line sorbent extraction for preconcentration and separation Preconcentration using Fe-DDTC; evaluation of interferences from co-existing elements studied (0.1-5 ng ml-I) (Cd Co Cr Cu Mn Ni Pb V and Zn) Preconcentration using either Chelex-100 or Hyphan reported; evaluation of the Contract Laboratory Programme (CLP) of the EPA Preconcentration using a cellulose-Zn(OH) mixture; effects of Zn concentration cellulose mass shaking time and pH studied (Cd Cr Cu Fe Hg La Ni Pd Sn and vanadate) Preconcentration using a sulfonated dithizone-loaded anion-exchange resin (Co Cu Ni and Pb) Comparison of furnace atomization non-thermal emission spectrometry with other ETV techniques; matrix separation required for furnace atomization non-thermal emission spectrometry Atomisation using a W coil; optimization of On-line preconcentration using Amberlite XAD-2 Zn) Sorption capacity of polystyrene- 93lC159 9 3/C 165 93/c193 93/C240 93/c311 931c312 931442 931443 931448 931473 931482 931498 931533 93/55 1 931561 931590JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Table 2. (c~mtinued ) 39 R Technique; atomization; Element Matrix analyte form* Various Water AA;F;L A A;ETA; L AA;cold vapour;L AA;-;L AA;-;L Sample treatment/commentst Reference Review of national standards speciation routine 93i623 analytical procedures sample collection sample containers sample filtration sample preservation sample pre-treatment and analytical procedures for waters sewage and effluents marine analysis diethylammonium DDC into TBMK (Cd Co Cr Cu Fe Mn Ni Pb and Zn) evaporation (Ca Fe Mg Na and Zn) experimental conditions important (Cd Cr Cu.Ni Pb and Zn) 8-hydroxyquinoline on Amberlite XAD-4; optimum conditions investigated (Cd Co Cu Fe Mn Ni and Pb) using 1% NaBH and 5% KI (2 3 and 3 ng ml-' for As Sb and Se respectively) Immobilized PbO supported on SiO used as the packing material in a solid-phase reactor; on-line FI oxidation of organic compounds allows monitoring of mobilized Pb Reference materials for the determination of elements in Mediterranean marine ecosystems; two new RMs reported (coastal sediment and green algae) Review of the application of atomic spectroscopy in 93/624 93!'658 Solvent extraction of buffered (pH 5.7) sample using Preconcentration of highly purified water by Investigation into possible interferences; choice of 931712 931727 Preconcentration using APDC and 93/76 1 On-line HG of acidified ( 3 mol 1-' HCl) sample Various Marine water Various (9) Brine water Various ( 5 ) Water Various (6) Rain water A A; ETA; L A A;ETA; L Various ( 7 ) River water AA;F;L Various (3) Water AE;ICP;L 93/769 931776 Va r io us Water (oxidizable organic compounds) Various Water AA;F;L AE;ICP;L A A; ETA; L IN A A;-;L AE;GD;L XRF;-;L AE;ICP;L 9 31840 Various Sea-water Preconcentration using minicolumns of 8-hydroxylquinoline or 1 -( 2-thiazoylazo)-2-naphthol with Amberlite XAD-2 resin in environmental samples; role of chemical modifiers sample preparation slurry sampling ( Al Cd Co Cr Cu Mn Ni Pb Si and Zn) Role of microwave dissolution for environmental monitoring discussed Preconcentration using electrochemically deposited Mg(OH) as a collector; application to marine geology evaluated Coprecipitation using CaCO,; water supersaturated by bubbling C02 (pH reduced to 4.9-5.0).optimimum precipitation carried out by alkalization at the isoelectric point of CaCO at pH 8.6 Monitoring of waste waters; preconcentration using precipitate flotation method. Potassium ethyl xanthate was used to form chelate complex; flotation conditions improved by addition of potassium oleate (Co Cu Mn and Zn) Review of technique for environmental analysis Application of plasma techniques to the analysis of Review of methods for trace element determination atmospheric precipitation (Al Ba Ca Cr Fe Mg Mn Na V and Zn) Method 200.8 in a routine analytical laboratory from cider production); waste chemically modified with P( V ) oxychloride to improve physico- chemical characteristics.Influence of pH and flow rate studied; elution with HCl Certification of two freshwater reference materials CRM 399 (high element content) and CRM 398 (low element content); analytical work for the certification of the materials detailed including homogeneity and stability studies Evalution of sampling methods for a reconnaissance survey of river waters in former metal mining areas of Wales Report on practical experiences with USEPA Preconcentration onto a solid support (apple waste 931845 Various (10) Sea-water AA;ETA;L Sl 93 a x 0 931C898 93iC928 Various Surface water Various (30) Sea-water AA;ETA;L AA;F;L A A ;-; L INAA;-;L _- ; :L 93iC931 Various Sea-water 931C9.55 Various (4) Waste water AE;ICP;L 931998 93!1055 Various Natural water Various (10) Rain water MS;ICP;L AE:ICP;L M S;I CP; L 9311077 Various (71) Natural water Various Water MS;ICP;L AA;-;L 93/11 10 9311 I27 Various (10) Fresh water MS;ICP;L 93il135 Various Natural water40R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Table 2. (continued) Technique; atomization; analyte form* Sample treatment/commentst Investigation into mineral leaching from bottles stoppered with rubber corks; six stoppers evaluated over a period of 6 d.Clean polypropylene bottles filled with either de-ionized water (pH 4.5) or acidified de-ionized water (pH 2.5); mineral leachates more pronounced with the acidifed water samples (Cr Cu Fe Mg Mn Se and Zn) Arabia reported Analysis of drinking water from Riyadh Saudia Review of AF in environmental monitoring Acid mine drainage and spoil tip run-off from metal First row transition elements determined using high- Comparison of analytical methodology with INAA An intelligent data management system for water quality studies reported by USGS Chelation preconcentration using a MetPac CC-1 column is used to eliminate matrix interference effects from alkali and alkaline earth elements C1 %bonded silica reversed phase column; metals extracted as DDC complexes prior to separation.Effects of flow rates sample pH and concentration of complexing agent considered (Cd Co Cu and Pb) On-line preconcentration using a column of silica- immobilized 8-hydroxyquinoline (0.3 6.9 4.2 1.8 10.2 5.7 and 1.8 pg for Cd Cu Fe Mn Ni Pb and Zn respectively) Measurement of trace elements in the Mississippi and Colorada rivers; study of water quality Comparison of on-line preconcentration-separation techniques using either a silica-immobilized 8-hydroxyquinoline column or a commercial MetPac CC-1 column (Cd Cu Mn Ni Pb and Zn) Development of an original identification method by detailed chemical analysis (fingerprinting) of the aquifers in the Yucca Mountain Nevada region USA Methodology for analysis of water/sediment samples; sample reproducibility improved using an ultrasonic cell homogenizer digestion in closed Teflon vessels and clean-up using ion chromatography prior to determination cellulose ion-exchange resin; automated on-line and off-line batch methods compared.Accuracy assessed by analysis of CRMs ( A s O ~ ~ - PO,3- SO,'- and Si03*-) mining areas of Wales reported resolution MS with an ultrasonic nebulizer On-line flow injection preconcentration using a Preconcentration using iminodiacetic acid-ethyl Preconcentration using a fibrous ion exchanger Reference 9311181 9311209 9311214 93/C1341 93/C 1342 93/c 1424 93 JC1343 93/C 1458 931c1470 93/C1471 931C1476 931C1482 93/C 1483 93/C 1543 93/C 633 931 672 9311768 9311 845 9311987 9312055 Element Matrix Various (7) Drinking water AA;-;L Various (13) Natural water MS;ICP;L AF;-;L MS;ICP;L Various (4) Waste water Various Waste water Various Terrestrial water MS;ICPL MS;ICP;L ; ;L __ Various (20) Groundwater Various Natural water Various Natural water (REEs) MS;ICP;L Various (4) Sea-water AAETA;L Laser excited AF;ETA;L Various Sea-water A A;ETA;L Various (17) River water Various (6) Sea-water MS;ICP;L MS;ICPL Various Ground water MS;ICP;L Various Natural water AE;ICP;L Various Fresh and sea-water AE;ICP;L Various (4) Water XRF;-;L Various ( 5 ) Drinking water XRF;-;L Preconcentration using Ostsorb OXIN a chelating ion exchange resin; radionuclide determination (Cr Cu Fe Pb and Zn) parameters of water quality monitored of residue 8-hydroxyquinoline; analysis of Open Ocean Sea- Water RM NASS-3.For Fe and Mo the sea-water was adjusted to pH 3 for other elements to 8.0 prior to passage through the column. ID determination of Fe using 56Fe as the reference isotope and "Fe as the spike required the use of N,-Ar mixed gas plasma with partial aerosol desolvation (0.04-6.3 pg ml-') Review of methods to collect uncontaminated samples at a depth of 2.5 km; methods to remove impurities caused by metal drills outlined. Comparison of technique with IDMS and ETAAS River pollution in the Ngong River in Kenya; ten Evaporation of solution followed by direct analysis Preconcentration using silica-immobilized Various River water Various Water Various ( 11) Sea-water X RF;-; L EDXRF;-;L MS;ICPL Various Ice and snow Laser excited AF;-;L 9312 140JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Table 2. (continued) 41 R Technique; atomization; Element Matrix analyte form* Various Sea-water MS;ICP;L WEE) Sample treatmen t/commentst Reference Preconcentration using bis( 2-ethylhexyl) hydrogen 9312155 phosphate and 2-ethylhexyl dihydrogen phosphate adsorbed on a C1 cartridge; conditions optimized include pH of sample amount of complexing agent on column flow rate volume of sample and concentration and volume of acid for elution Characterization of groundwater categories at the foot of the Swiss Jura between Geneva and Lausanne preconcentration of trace metals Review of POLYORGS as a complexing agent for Direct determination of diluted samples (0.5 pg ml-') Various Groundwater AE;ICP;L 9312178 Various Water - ; ;L MS;ICP;L AE;ICP;L MS;ICP;L M S;ICP;L 9312181 Various Natural water Various Drinking water Various (61) Pure water (REE) 9312206 Use of ultrasonic nebulization (2.5-100 ng ml-') Direct determination in sub-boiled high purity water Use of ultrasonic nebulizer with high resolution MS (sub-pg m1-I) (sub pg m1-I) 9312208 9312222 Various Natural water (lanthanides and actinides) Various Natural water 9312224 MS;ICP;L Review of applications to speciation studies using either chromatography (GC and HPLC) or extraction Analysis of two candidate RMs low-mineral content (CRM 398) and high-mineral content fresh water (CRM 399).See also ref. 9311127 (30 ng g-'-80 Experiences with a computer-controlled instrument Review (2 refs.) on optimization and principles of Application of technique; coprecipitation with P8 g-') technique Fe(OH) used to separate and preconcentrate elements from brine samples Ultrasonic nebulization used to analyse samples using double-focusing and high resolution MS (0.5-1 1.6 fg ml-') Use of N20-C3H8/C4Hl flame for Li and Cs air-C,H for Cs and Sr and N,O-C2H2 for Ba Optimization of manifold design for on-line microwave sample pre-treatment; see also 9312718 Chemistry and applications of on-line microwave sample pre-treatment; see also 9312717 Review of advances in coupled techniques for speciation studies Simultaneous determination of hydride and non- hydride forming elements.See also ref. 93fC240 Coprecipitation using Al(OH) adjusted to pH 7.3 followed by EDXRF (0.2-0.8 ng ml-') Preconcentration using Chelex-100 on board ship; direct determination using 0.2 pg g-' Lu as spike and internal standafd speciation studies of organometallics prior to separation by GC reported Preconcentration procedures for ultra-trace Review of developments in instrumentation Preconcentration using on-line FI with a micro flow- through electrolytic cell Solvent extraction using 5-( 2-carbomethoxypheny1)- azo-8-quinolinol as complexing agent; sample adjusted to pH 5.5-6.5 0.05% acetone solution of reagent added and complexes extracted into IBMK (2-500 ng ml-') separation using C18 column (Cd Co Cu Pb and Ni) (pg ml-') Preconcentration by sorption on sulfide-modified hydrated Sn02 Comparison of techniques for the determination of elements in cloud water; samples collected using the ASRC omnidirectional cloud water collector and freeze-dried until required analysis of pollutants using microwave digestion On-line complexation using Na DDC prior to Guidelines for establishing test procedures for the 9312254 Various Natural water MS;ICP;L 9312 3 24 Various Waste water Various Waste water MS;ICP;L MS;ICP;L MS;ICP;L 9312347 9312389 9312604 Various Natural water 9312621 Various Fresh water WEE) MS;ICP;L Various (5) Potable water AE;F;L 9312641 9312717 93/27 18 9 312 7 30 9312732 9312757 9312987 Various Water AA;cold vapour AA;cold vapour HY;L Hy;L ; ;L _ _ Various Water Various Water AE;ICP;L Various Water Various Water XRF;-;L MS;ICP;L Various Sea-water W E ) 931c3030 Various Natural water AE;MIP;L 93fC3037 93lC3055 Various Water Various Sea-water MS;ICP;L AE;ICP;L AA;F;L 9313 103 Various Natural water 9313110 AA; E TA; L Various (5) Water AE;-;L 9 313 200 9313207 Various Fresh water Various Cloud water NAA;-;L AA;Hy;L 9313278 Various Water AE;ICPL AE;DCP;L AA;-;L42 R Table 2.(continued) JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 Technique; atomization; Element Matrix analyte form* Various Water AA;-;L Various Sea-water AA;-;L AE;ICP;L Reference Sample treatment/commentst Review of instrumentation in the framework of Distribution of heavy metals within the intra- 9313300 9313334 legislational water analysis thermocline eddies of the intrusion of Mediterranean sea-water in the sub-tropical region of the North Atlantic Ocean immobilized onto silica (0.3-10.3 pg) parameters investigated include sample volume purge gas flow rate and concentration of reductant (0.5-7 pg ml-l) HCL (0.1-0.05 ng ml-') On-line preconcentration using 8-hydroxyquinoline Optimization of FI vapour generation technique; Development of system using a boosted-discharge Various Various Sea-wa ter Sea-water AA;ETA;L 9313372 9 313 404 MS;ICP;L Water AF;F Ar-H Hy;L 9313408 Various Review of techniques for matrix-free determination Sampling methods outlined for determination of trace metals in the Bassa Valdelsa Province of Italy Comparison with ASV Multivariate statistical analysis of the composition of Preconcentration using AN-5 11 anion-exchange rain water near Cubatao SP Brazil resin; optimal sorption for a 1 1 sample is achieved at pH 6-7 for 30 min Preconcentration using a polymeric chelating agent D40 1 Isotopic analysis of water using a small MS SMAD-2A; improvements in maintenance automation data acquisition and processing are presented Evaluation of chelation ion-exchange resins for on-line or off-line use; EDTrA HYPHAN and TETPA tested for multi-element enrichment (0.03-0.5 ng ml- I ) Ultrasonic nebulizer used with high resolution MS instrument (1 pg m1-l) Metal determination in leachate from an industrial waste landfill located in the Kanto area Japan Review of methods to determine metals in industrial water samples Review of methods to determine metals in industrial water samples Review of modern multi-element methods of analysis Various Various Sea-water Snow MS;ICP;L AA;ETA;L 9313446 9313486 Various Various Water Rain water 93 1349 1 9313520 AA;-;L Various Natural water 9313668 Various Various Sea-water Water AA;-;L 9313682 9313715 MS;-;L Various Water AE;ICP;L AA;F;L 9313783 MS;ICP;L Various Various Various Various Various Water Landfill leachate Water Water Natural water 9313785 9314056 9 3/40 5 9 9314060 9314106 AE;ICP;L AA;ETA;L AE;ICP;L AA;F;L A A;ETA; L AE;ICP;L NAA;-;L AE;ICP;L MS;ICP;L Various Water Review of merits and limitations of each technique 9314 109 ~ ~ ~~ * Hy indicates hydride and S L G and S1 signify solid liquid gaseous or slurry sample introduction respectively.Other abbreviations are t Values in parentheses are detection limits. listed elsewhere. dissolved in acetone and digested with HN03 and HC104 before determination by HG-AAS.He has also devised a similar procedure for As"' (93/2180). mation (93/3924). Detection limits were all below 1 pg 1-l and sample throughput was between 13 and 30 h-l. It is always attractive to use a multi-element technique such as ICP-AES for the simultaneous determination of hydride forming elements but there are pitfalls for the unwary. Pretorius et al. (93/769) reported detection limits of 2 3 and 3 pg I-' for As Sb and Se respectively in waters by HG-ICP-AES. However it is unlikely that the reaction conditions they employed using sodium tetrahydroborate and KI would be sufficient to reduce any SeV' present to Se" prior to HG. Haraldsson and co-workers (93/3387) in similar work with ICP-MS replaced KI with APDC because iodide interfered in the generation of Se hydride.They obtained much superior detection limits of 1.5 2.4 and 6.3 ng I-' for As Sb and Se respectively. Most of the other vapour generation methods detailed in Table 2 are for individual elements and many include an 2.1.7. Hydride and cold uapour generation Flow injection techniques are increasingly used to enhance the performance of hydride generation ETAAS by providing higher sample throughputs improved absolute LODs and ease of automation. Tsalev and co-workers (93/2717,93/2718,93/3924) have investigated the most appropriate reaction conditions for the operation of their fully automated HG and CVAAS system which incorporates on-line microwave digestion. Samples were mixed with an appropriate oxidation reagent and loaded onto an autosampler; sample uptake digestion measurement cali- bration and data processing were performed automatically.Mercury could also be determined with and without amalga-JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 43 R aspect on speciation as well. Separation with HPLC combined with an automated HG-AAS system has been used to provide data on arsenic species in sea-water (93/1141). Ion-exclusion chromatography was combined with continuous HG-AAS for the simultaneous determination of As'' and AsV in geothermal waters (93/3096). In this type of application it is important to note that the samples were acidified with HC1 to pH 2 on sampling to maintain the status of the As species. Variations on the CVAAS method for the determination of H g in waters with preconcentration on gold have been reported (93/484 and 93/2677).However quantification using AFS is gaining in popularity. Liang and Bloom (93/3229) used AFS detection after a single Au amalgamation step and reported an absolute LOD of less than 1 pg. Swift and Campbell (93/3714) detected Hg at ng 1-1 concentrations in river waters using a commercially available CVAFS system. Xanthate cotton ion-exchange fibres have also been used to preconcen- trate Hg prior to reduction with sodium metaborate and detection by AFS (93/1239); the LODs were not as impressive as those from the commercial system above. Results of interlab- oratory comparisons for the determination of total Hg have been published (93/2677); samples containing organic Hg were oxidized with KMn0,-K2S,0s and all samples were stabilized with K2Cr207 in HN03.Tyson et al. (93/C64) devised an FI procedure incorporating a simple on-line oxidative pre- treatment with concentrated H2S0 which proved sufficient to release all the organically bound Hg prior to reduction with SnC1,. 2.1.8. Speciation A general review of advances in coupled techniquesfor speciation highlights three new developments in the field GC-MIP-AES GC-ICP-MS and HPLC-ICP-MS (93/2730). Using these techniques with the low LODs they provide it is now possible to monitor both the metallic and non-metallic components of a sample simultaneously. Lespes et al. (93/2254) also reviewed the possibilities of achieving the speciation of organometallic compounds using ICP-MS and described the main experimen- tal conditions pertaining to each of the 32 refs.Lobinski and Adams (93/2069 93/31 17) used GC-MIP-AES after sample preconcentration to determine organolead species; members of the same group have also reported quantification of Sn species The separation of butyltin species can be effected in several ways (93/1099 93/4033 93/4121). The property of tropolone to form stable complexes with mono- and di-butyltin was used by Astruc et al. (93/1099) to separate aqueous butyltin com- pounds by LC on cyanopropyl-bonded silica columns. The eluent was a solution of tropolone in toluene and detection was by ETAAS. A group of Chinese workers used a GC-AAS method to determine trace concentrations of butyltin com- pounds in sea water (93/4033).They reported LODs of approximately 20 20 and 70 ng 1-1 Sn for monobutyltin dibutyltin and tributyltin respectively. Gremm and Frimmel (93/4121) employed AE detection after separation of the tin species by GC. The results of a round robin exercise for tributyltin in sea-water indicated that acceptable consensus could be obtained on a sample spiked with 175 ng l-l but there were inherent difficulties in obtaining good precision at 20 ng 1-1 and below (93/1191). by GC-MIP-AES (93/C3033). 2.2. Instrumental Analysis 2.2.1. Atomic absorption spectrometry In spite of the advent of ICP based techniques AAS and ETAAS continue to be used routinely in many laboratories for the analysis of waters. Therefore two reviews on the application of AAS to the analysis of waters and other materials are pertinent (93/623,93/624).The first is an authoritative and comprehensive review with 132 refs. It covers all aspects of the collection and preservation of samples as well as analytical procedures for AAS ETAAS CVAAS and HG-AAS (93/623). The second review has 138 refs. and deals specifically with the application of AAS to marine analysis including sea-water (93/624). Several different chemical mod$ers have been reported for the determination of trace elements in sea-water by ETAAS (93/719 93/1225,93/2727). Tartaric acid was used to eliminate suppression on copper signals (93/1225) and tartaric acid plus HN03 was claimed to be effective for the direct measurement of Cd in sea-water by ETAAS (93/719). Lan (93/2727) used NaOH as a chemical modifier in a similar study of Cd in sea- water by ETAAS.The addition of this reagent produced a precipitate of magnesium hydroxide and trace amounts of Cd were coprecipitated. The sea-water matrix could be removed at 1400 "C with little loss of Cd; the LOD was 0.015 ng ml-'. From the continuing publication of AAS methods specifically for Cr it would appear that the determination of Cr and its species is still both of interest and analytically problematic (93/C46 93/1227 93/2896 93/3238 93/3243). Rubio et al. (93/4024) have attempted to bring together all the relevant literature particularly on interference effects in ETAAS some of which is contradictory. This review has 83 refs. and covers methods of pre-treatment for natural and sea-waters as well as parameters and interference effects in the measurement of Cr by AAS and ETAAS.Last year it appeared that most of the research on the use of tungsten wire for preconcentration of metals prior to analysis by ETAAS was focused in China. This technique has also been applied by Suttie and Wolff (93/442) to the exacting task of determining very low levels of metals in Antarctic snow; LODs of 0.01 (Cd) 0.47 (Cu) 0.22 (Pb) and 0.24 (Zn) ng kg-I were reported. 2.2.2. Atomic Emission Inductively coupled plasma atomic emission spectrometry is a well established technique for multi-element analysis of a wide range of water types such as landfill leachate (93/4056) and effluent from industrial processes (93/4060). However a survey of trace elements in groundwaters in Switzerland found that only Ba Fe Li Sr and Zn concentrations were significantly above the LODs that could be achieved with ICP-AES (93/2178).This will come as no surprise to those working with natural waters and highlights why much of the research effort in this area centres around lowering the LODs. In such circumstances one alternative is to use the more sensitive technique of ICP-MS. Anyone trying to decide which ICP technology is more suitable for their application might benefit from consulting the review in German by Broekaert (93/4109). It contains 51 refs. and covers the advantages and limitations of ICP-AES and ICP-MS for water analysis with examples for waste water fresh water and sea-water. Jickells et al. (93/1055) also illustrate the application of both techniques to the multi-elemental analysis of rainwater.Their strategy was to develop ICP-AES methods where possible because this instrumentation is readily accessible and to use ICP-MS for those elements where ICP-AES is inappropriate. Another tactic is to use an ultrasonic nebulizer in conjunction with ICP-AES. Anderson (93/2208) reported the usual improvement in LODs of about an order of magnitude with good long-term stability for the analysis of drinking water. Ultrasonic nebulizers have been on the market for many years and if they are really as good as this type of report implies it is surprising that very few laboratories employ them on a routine basis. Mention is made of some of the disadvantages such as more and larger spectral interferences from the matrix elements which are also concentrated in the process; other drawbacks which include longer analysis time and loss of some volatile elements such as B were not considered.Other workers have opted for more conventional preconcen-44 R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 tration techniques coupled to ICP-AES. A fast routine pro- cedure with enrichment factors of 20 or greater was achieved by Wuensch et al. (93/533) using two chelating resins (Chelex-100 and Hyphan) to preconcentrate the determinands sufficiently to fulfil the LOD requirements of the Environmental Protection Agency (EPA) requirements. Most of the work reported in this area has been in the analysis of sea-water by ICP-AES where it is desirable to achieve separ- ation from the matrix elements as well as preconcentration of the determinands of interest.An Italian group used 8-hydroxyquinoline in conjunction with Amberlite XAD-2 resin to study trace metals in Antartic sea-water (93/845 93/433). This on-line system improved the LODs for Cd Cu Fe Mn Ni and Zn by a factor of 100 compared with direct nebulization ICP-AES. Table 2 contains details of other approaches. One of the more novel analytical schemes put forward this year was the combination of continuous hydride generation with conventional ICP nebulization thereby adding As Se and Sb to the elements determined simultaneously by ICP-AES (93/2732 93/C240). The sample stream was split with one stream pumped directly to the nebulizer; the other was mixed with HCl and NaBH and the hydrides generated swept into the spray chamber through a modified cross-flow nebulizer cap.The system which is still under development requires an on-line procedure to reduce the higher oxidation states of these three elements prior to hydride formation. Microwave induced plasmas are often used as an alternative emission source in studies concerned with speciation and for coupling to chromatographic separation systems. Gas chromatography-MIP-AES has been used for the speciation of organotin (93/C3033) and organolead compounds (93/2069 93/3 117). One of the main advantages of the MIP is its ability to quantify the halogens. Therefore Nakahara and co-workers (93/585 93/2122) have used an atmospheric-pressure helium MIP to determine Br and I in sea-waters.In each case the anion was oxidized to the elemental vapour before being swept into an MIP. 2.2.3. X-Ray fluorescence This year strategies for converting aqueous samples into a suitable form for multi-element analysis by XRF have included the use of the chelating cellulose exchanger Ostsorb-oxin (93/1768) polyacrylonitrile fibre modified with polyethyl- ene polyamide (93/1672) and simple evaporation onto thin plastic film (93/1987). Straightforward coprecipitation of trace elements on aluminium hydroxide was combined with EDXRF to give LODs in the range of 0.2-0.8 ng ml-' for a number of elements (93/2757). However this method suffered from prob- lems with organics in real waters which may require pre- digestion and could not be used for sea-water because the precipitate was too flaky.Several methods for the determination of individual elements by XRF have been reported including P in waste water (93/2758) As in natural waters (93/2756) '"I in drinking waters (93/1717) and Au in leaching solutions and natural waters (93/1666). Table 2 should be consulted for further details. It is perhaps surprising that no new papers on methods for water analysis by TXRF appeared this year. 2.2.4. Mass spectrometry Inductively coupled plasma mass spectrometry is now in regular use for the analysis of waters as many laboratories take advantage of its multi-elemental capability combined with low LODs for aqueous solutions. Table 2 gives many examples of its use worldwide including the analysis of river water (93/C1476) high purity water ((93/2222) drinking water (93/1209) fingerprinting of groundwater (C1483) mine drain- age (C1341) and waste water (93/2389).These and other papers describe the principles and application of ICP-MS to aqueous samples without contributing anything particularly new about the technique. Vanhaecke et al. (93/2324) analysed two candi- date fresh water CRMs. As is often the case the metal concentrations were comparatively high in these CRMs com- pared with the levels in many natural waters. However they reported that not only were excellent results obtained for interference-free trace elements but they felt that ICP-MS was also competitive against other techniques for less ideal elements such as Ca C1 and Fe. The indication is that most users are getting to grips with the well-known polyatornic ion interferences.A short paper has however addressed the interference of inorganic carbon on the determination of 52Cr (93/3081). The workers solved this problem by measuring I3C and incorporating a correction factor into the software. Garman and Mackenzie (93/1077) noted that the US EPA ICP-MS method 200.8 for waters does not cover the determination of Fe. In the writer's opinion this is for several very good reasons. However in their rather uncritical review of the EPA method they claimed they could achieve a detection limit of 1 pg 1-' using 54Fe which is surprising in view of the isobaric interferences from ,'ArN ,'CaN and ',Cr. One way to overcome potential polyatomic interferences is to use high-resolution ICP-MS to resolve the determinand mass peak from that of the interfering polyatomic ion.Tsumura and Yamasaki demonstrated the use of such an instrument in combination with an ultrasonic nebulizer to determine ppt levels of trace elements (93/C1342 93/3785) and lanthanides and actinides (93/2224 93/2621) in waters without pre- concentration. There appears to be a considerable surge of interest in the measurement of rare earth elements (REEs) in natural waters. Although Stroh (93/2206) obtained LODs of about 0.5 pg ml-I for REE in spiked samples of sea-water without any pre- treatment of his samples the naturally low abundances of these elements in many waters forces most workers to employ some sort of preconcentration. Vaive et al. (93/C1458) used a fully automated Dionex Chelation Module with a MetPac CC-1 column and fraction collector to preconcentrate the REEs together with a selection of transition elements.Forty samples could be preconcentrated 10-fold in less than 24 h without operator assistance. Shabani et al. (93/2155) obtained enrichment factors of between 200 and 1000 for the REEs by passing 1 1 of sea-water through a CI8 cartridge loaded with a mixture of bis( 2-ethylhexyl) hydrogen phosphate and 2-ethylhexyl dihydrogen phosphate. Researchers from Germany reported even greater concentration factors (11.5 1 down to 35ml) for REE in sea-water by passing samples spiked with Lu through Chelex-100 chelating resin (93/2987). The accuracy of this method was estimated to be about _+ lo% except for La and Ce; La in particular suffered from high blanks.A review of the application of ICP-MS to speciation studies suggests that the analytical schemes fall into two camps separative extraction or gas or liquid chromatography coupled with ICP-MS (93/2254). The same comment is true of the methods devised for the determination of the very low levels of trace elements present in sea-water by ICP-MS. Elements which have been extracted from sea-water by chemical separ- ation prior to ICP-MS include Bi (93/1040) Re (93/2319) and Re and Pt (93/3442). Iron and ten other trace elements were separated and preconcentrated from the sea-water RM NASS-3 using silica-immobilized 8-hydroxyquinoline (93/2055). Iron and Mo were separated from a sample with the pH adjusted to 3 whereas the rest of the metals were preconcentrated at pH 8.One of the novel aspects of this method was the determination of Fe using ID plus an N,-Ar2 mixed-gas plasma and partial aerosol desolvation to virtually eliminate the ArO interference on 56Fe. Bloxham et al. (93/3446) took the other approach and emphasized the coupled use of FI and LC with ICP-MS for determinand preconcentration and matrixJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 45 R removal. Their review article with 33 refs. includes some of the coupled chromatographic approaches which have been applied to the determination of trace metals in sea-water; the use of mixed-gas plasmas and multivariate calibration tech- niques for matrix suppression are also discussed. An improved method for the determination of mercury by inductively coupled plasma mass spectrometry has been reported (93/2163).Conventional nebulization is beset by problems arising from memory effects. These have been overcome by using direct injection nebulization and the results compared with those from CVAAS for concentrations of Hg in drinking waters. A conference paper evaluated the use of ICP-MS for the determination of 226Ra in drinking water as an alternative to scintillation counting of the Rn daughter product after separ- ation (93/C1583). The samples were prepared using an ion- exchange scheme and the procedure achieved the required EPA LOD of 1 pg 1-'. The conclusion was that the ICP-MS method provided adequate sensitivity while decreasing the analysis time significantly. Isotope analysis remains by and large the province of conventional MS.This year there have been several examples of the current interest in the B isotope ratio of waters. Thermal ionization mass spectrometry was used on samples prepared as the Cs2B02+ ion to trace the source of waters flowing into a Chinese lake (93/3099); another study employed an ion- exchange method for extracting and purifying B prior to caesium metaborate mass spectrometric determination (93/2342). Boron isotopes have also been used to identify fly ash leachate in groundwater (93/2937). Isotope dilution mass spectrometry was used to determine trace concentrations of U (93,4246) and Pb (93/2424) in waters; the Pb method was blank limited and the LOD was 0.3 ng g- for a 0.2 ml sample. A comprehensive study of Re in sea-water was based on the precise measurement of Re by ID and negative TIMS (93/3101); typical precision was + O S % at 7 ng kg-'.3. ANALYSIS OF SOILS PLANTS AND RELATED MATERIALS The format of the third section of this Environmental Analysis Update is similar to that in last year's update (93/3417) reflecting the similar trends in the work published and pre- sented at conferences. The balance within sections has changed a little. Although sample preparation and speciation continue to be dominant features there is marginally less to report on novel developments in AES and AAS. Interest in ICP-MS and other MS techniques is apparently continuing to grow how- ever and XRF too continues to attract considerable attention. These trends are reflected in Table 3 which summarizes devel- opments over the 12 month review period in the analysis of soils plants and related materials.Before discussing the most important and useful develop- ments of the past year in more detail it is appropriate here to highlight useful general reviews appropriate to this section of the Update. A report from the Environmental Monitoring Systems Laboratory in Cincinnati OH USA covered 13 analytical methods for 36 determinants in a range of environ- mental samples which included soils and sediments (93/3683). A wide selection of atomic spectrometry methods was included. A somewhat less comprehensive review of applications of AES INAA and flame and furnace AAS with 24 refs. has been published in Russian (93/4106). Its scope included plant mate- rials as well as atmospheric aerosol and water samples.Fodor and Bertenyi (93/839) reviewed the problems associated with the analysis of environmental samples by ICP-AES; the paper is mentioned here because the authors considered the problems of potential losses of trace elements during washing of samples as opposed to contamination risk if plant samples are not washed. They also commented upon the significant losses of Al Cr Cu and Ni which occurred during ashing even when precautions such as chemical modification were taken. An overview of atomic spectrometric techniques for soil and plant analysis presented at a conference concluded that no single atomic spectrometric technique is capable alone of meeting the requirements of environmental scientists (93/C4). The determination of toxic elements in soils has been reviewed in Japanese by Kubota (93/2734).It is not always a straightforward matter to decide upon the most appropriate sample preparation procedure when assessing heavy metals in soils. A book chapter on the analysis of polluted soils by AAS therefore also contains some useful general information on aspects of sample preparation including aspects of speciation (93/634). Apart from the broadly based reviews mentioned above one review of a more specific topic deserves a mention here. Rubio et al. (93/4024) have published a useful account of the determi- nation of chromium in environmental and biological samples. The review with 83 refs. concentrates upon AAS-based procedures. 3.1. Soil and Plant Reference Materials Although little useful novel work on certijed reference materials has appeared for soils three publications concerned with plant CRMs are worthy of mention although they were probably published more with the needs of foodstuff analysts in mind. Okamoto (93/2699) has published details of a rice flour CRM with values for 13 major and trace elements.Stable isotope dilution was applied for the accurate certification of Cd Cu Mo and Zn concentrations and homogeneity was proved adequate. A European study of vegetal SRMs involved 38 laboratories using INAA AAS ICP-AES and XRF (93/2396). Certification of S content of plant samples is becoming increas- ingly useful as the element is determined much more often nowadays by ICP-AES. Wagstaffe and colleagues (93/2733) used ICP-AES isotope dilution MS and ion chromatography for the certification of three rapeseed RMs. 3.2.Sample Preparation Genuinely innovative methods for sample preparation are rare in the context of this section of the review and therefore the paper on sedimentation field $ow fractionation by Chittleborough et al. (93/4107) is particularly noteworthy. The technique produces high resolution separations of a wide range of macromolecules and particulates and especially when coupled with ICP-MS appears to be highly promising for characterization of soil colloids. Further development and evaluation is awaited with interest. It is also unusual nowadays to see new methods being published for the determinution of cation-exchange capacity and exchangeable base cations. Nevertheless hexaminocobalt (as the chloride) has been suggested as a saturating and displacing cation for this purpose displaced Ca and Mg being determined as usual by FAAS (93/1263). It is hard to conceive of this approach obtaining widespread routine use.3.2.1. Sample dissolution Sample dissolution or at least dissolution of the determinant is still regarded as mandatory in most laboratories analysing plant soil and fertilizer samples by nebulization-based atomic spectrometric procedures. As in the past the most recent review year has seen a diverse range of acid cocktails being used to effect sample dissolution by acid digestion. For example a HF + HC104 mixture has been advocated for digestion prior to the determination of Ca Cu Fe Mg Na Ti and Zn in various parts of tomato plants by ICP-AES (93/1240).Fertilizers have been dissolved with a mixture of HF+HNO at 170 "C under pressure for Be determination (93/C900).46 R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 Table 3 SUMMARY OF ANALYSES OF SOILS PLANTS AND RELATED MATERIALS Element Matrix A1 Fine roots A1 Soybean plants As Polluted soils compounds As As Au B B B B Ba Be Bi Bi Bi Butyltin Ca Cd species Cd Cd Cd Cd Cd c o co c o c o c s c u cu Ge Fertilizer Soils herbage Soil sludge Soils Plants Soils Soils Soils Fertilizers Soil Environmental materials Soil herbage Sewage sludge Bamboo shoot Plant tissues Herbage Soil Rice plants Environmental samples Leaves Plant tissues Pepperbush Soil Soil Soil Isolated plant cells Soil Soils sediments Technique; atomization; analyte form* AE;laser;S AE;ICP;L AA;F H,-Ar;L MS;ICP;L AA;F air-C,H HY;G AE;ICP Hy;L AE;ICP;L AE;ICP;L AE;ICP;L AE;ICP;L MS;ICP;L AAF N,O-C,H,;SI AA;ETA;L AA;quartz cell HY;L AA;ETA;L AE;ICP Hy;L AA;H furnace;G AA;F air-C,H,; L AA;F;L AA; ETA,L AA;ETA;Sl AA;F;L AE;ICP ETV;L AA;F;L AA;F;L AA;F;L AA;-;L AA;ETA;- AA;ETA;L MS;-;S AA;-;L __ ; 7 Hy;L Sample treatmentJcomments Laser microprobe analysis of spruce fine roots and Effect of soil pH on A1 uptake studied; samples Seven As compounds separated by HPLC and Sample dissolved in HNO + H,O then treated with their ectomycorrhizal mantles digested in acid determined with on-line detection HC1 KI and ascorbic acid prior to ASH generation with KBH Soils and plants in old metalliferous mining areas studied.As Bi and Sb in plants controlled by pH texture E, organic matter content and other element concentrations Au preconcentrated and separated on column of cotton fibre impregnated with CH,COSH Refluxing with 0.01 mol I-' CaCl found to be useful for B extraction from diverse soils; Results compared with those for hot water and mannitol extracts Samples predigested with HNO + H20 prior to microwave digestion for 2.25 min. B extracted with hot water; 1% NaOH sprayed for 1 min between samples to avoid memory effects Use of loB to trace B movement in plants and soil described The generation of cation-exchange surfaces on grinding minerals discussed in the context of the successful application of the standard additions method to Ba determination Samples digested with HF + HNO at 2 MPa; SiF removed by evaporation Bi and Sb extracted with 6 mol 1-' HCI then reduced with KI + ascorbic acid and finally with NaBH,.Elements determined by continuous-flow HG system with electrically heated atomizer Bi preconcentrated by anion exchange; palladium nitrate used as chemical modifier See As ref. 931C3043 Species extracted by cycloheptatrienone in toluene Routine procedure described Samples pre-digested with HNO or HNO + HCl then digested with HClO + H2S04. Fe"' added by FI system and reduced to Fe". Cd Co and Ni coprecipitated with Fe" as hexahydroazepinium hexahydroazepine-l-carbodithioate and precipitate dissolved in MIBK Cd accumulation modifier HNO +H,O for Cd and Ni determinations; conventional and FI nebulization employed Tungsten boat furnace vapourizer used to enhance sensitivity for Cd and Pb determinations Discrete sample nebulization used after solvent extraction of APDC complex into CHC1 See Cd ref.9312121 Novel preconcentration technique described based on ion pair formation with NH,' and tetraphenylborate anion supported on naphthalene; complex stripped with DMF moll-' EDTA and ethylated prior to GC separation Samples archived over 130 years analysed to show Agar suspension used with NH,H,PO as chemical Samples digested at room temperature with Co and Cu extracted with 0.1 mol 1-' HCl and 0.05 Graphite probe used for atomization Samples digested and Cs determined using a graphite platform and chemical modifier Novel application of RIMS described See Co ref. 9313537 Novel computer-controlled batch HG system described.Kalman filtering used for noise reduction Reference 9312660 931C3044 9311007 9312 169 93/c3043 931762 9311128 9311 158 9311202 9313509 9312087 931C900 931485 9311 125 931c3043 93/1035 931504 93/2 12 1 931851 9313 137 9313194 9313359 9313415 93/21 2 1 9312726 9313537 9314006 93/c73 9312894 9313537 93/C32JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 47 R Table 3 (continued) Technique; atomization; analyte form* AA;ETA;L Element Ge Hg Hg Hg Hg Hg HgS 1291 1291 K Mg Mn Mo Na Ni Ni Ni P Pb Pb Pb Pb Pb Pb Pb REE REE REE S S S S S Sz- SO,* Sb Sb Se Se Se Sn Sn Matrix Plants Sample treatmentJcomments Phenylfluorone Ge complex extracted with IBMK; Palladium + Mg(NO,) used as chemical modifier FANES used for Hg determination following microwave-assisted digestion Samples digested with HNO + HC104 and digests treated with KMnO then NH,OH.HCl prior to HgO generation with SnCl by use of hydrazine borate NH40H used as chemical modifier Interference from humic and fulvic acids overcome Microwave-assisted digestion with HC1+ HN03 used HNO and saturated Na,S used for selective extraction of HgS; 30% SnC1 used to produce HgO Element introduced into the plasma as I Element introduced into the plasma by ETV Sequential detectors used for P and K and Na in FI See Ca ref.93/504 Speciation study described based on solvent system extraction and coprecipitation of Mn,' with Samples dissolved by microwave-assisted digestion and Mo concentrated as MOO,- on Amberlite AWH) LA-2 See K ref.93/700 See Cd ref. 9312121 See Cd ref. 9313194 Ni extracted with CH,COOH + CH,COONH at pH P determined by laser-excited fluorescence Ultrasonic agitation used to ensure suspension Case study of urban Pb pollution Dithizone-polyurethane foam system used to pre- concentrate Pb Pb accumulation studied in relation to road traffic See Cd ref. 9313359 Samples dissolved by microwave-assisted digestion Pb concentrations in 42 plants in Greece evaluated Ashed sample digested with HCl+ H,O and REE extracted with l-phenyl-3-methyl-4-benzoyl-5-pyrazolone and isopentanol concentrations in soils 7.1 spectrometry using PO emission homogeneity REE in plants studied in relation to their Tungsten coil ETV system used to enhance sensitivity High resolution XRF used for S speciation ICP-AES ion chromatography and ID analysis used to certify RMs Calibration procedure described for use of total S content to predict glucosinolate content For soils with < 25% organic matter LOD was 4.5 mg kg-' ICP-AES and ion chromatography used in the analysis of sequential extracts of soils for speciation purposes Automated gas-phase sample handling system described for cool flame emission spectrometry Reference 9 313947 931412 9311644 9313 134 93/3625 9313714 931687 9311008 93/c1295 931700 931504 93JC150 93/2940 931700 9312 12 1 9313 194 9313537 9312074 93lC111 931850 931C902 9313325 9313359 93/3542 9314038 93/70 1 9311 137 93/3242 9311665 9312733 93/2740 93/2748 9313499 93/C88 931485 93/C3043 93/c93 3 9312195 9313978 9313964 9314057 River plants Leaves A A;ETA;L AE;ETA;G Tea and peach leaves AF;coId vapour;L Soil drainage water AA;cold vapour;L Soils Soils sediments AF;cold vapour;L AF;-;- Vegetables Vegetables Plant samples MS;ICP;L MS;ICP;L AE;F;L Bamboo shoot Tea samples AA;F air-C,H,;L _ _ ; ;L Plant material MS;-;- Plant materials Plant tissues Rice plants Soil AE;F;L AA;F;L AA;F;L AA;-;L Plants -;ETA;L Soil AA;ETA;SI Soil Soil AA;-:L AA;F;L Roadside soil Environmental samples Animal feeds Plants Tea leaves AA,FL AE;ICP ETV;L MS;ICP;L AE;ICP;L AA;-;L AE;ICP;L Plants Rice Leaves soil Rapeseed AE;ICPL AE;ICP;L XRF;-;S Rapeseed XRF;-;S Soil XRF;-;S Soil AE;ICP;L OE;F H,-ent rained air;L AA;quartz cell HY;L AE;ICP Hy;L AA;ETA;L N A A ;-;S AA;- Hy;L Various Soil See Bi ref.931485 Soil herbage Plants See As ref.93/C3043 Use of hex-l-ene for selective extraction of Se described Samples digested with HNO or HNO +HC104.6 mol I-' HCI used to reduce Se"' to $elV Several methods compared including atomic spectrometry Hydride trapped on palladium-coated L'vov platform Acetate extract filtered treated with picric acid and Sn extracted with crown ether into CHCI,. Extract diluted with C,H,OH Leaves AA;Hy;L AE;ICP;L AA;ETA Hy;L Plants Orchard leaves Soil AA;-;LJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 48 R Table 3 (continued) Technique; atomization; Element Matrix analyte form* Th Soils MS;-;S Sample treatment/comments compared for Th and U. Precision was six times better by TIMS; a highly-selective resin was evaluated for the clean-up procedure Samples digested with HNO + HClO and digests diluted with HCI.Ti and six nutrient elements determined Isotope dilution TIMS and SIMS procedures See Th ref. 9312892 Isotope ratios measured in samples enriched with Samples dissolved in HF + HClO,. U determined by ID technique HNO EDTA and some less common organic extractants compared Palladium used as modifier in determination of Cd Cr Cu Mo Ni Pb V and Zn in CH,COONH4 extracts Common Brazilian fruits analysed for Al Ca Cu Fe Mg Mn and Zn. Samples dried in microwave oven ashed and extracted with HNO + HC1 Identification of source of clay samples based upon determination of nine trace elements Arc between two enclosed electrodes above induction coil used for solid sample atomization 18 major and trace elements extracted with HF + HNO + HClO and then HC1; interference from Cu Pb and P overcome by matrix matching Losses of Al Cr Cu Mg and Ni during biological sample washing observed Al Cd Fe Pb and Ti fractionated into organic bound and soluble iron and aluminium oxide secondary mineral and primary mineral forms Absorption/desorption reactions of heavy metals in soils studied using radiotracers and AAS Application of FANES described. Problems were encountered with background interferences Pressed polyethylene-soil or soil-borax fusion disks analysed by two techniques; LA used for sample introduction to the ICP HCl+ HNO then H,02.Extractable trace metals measured in 2 moll- HNO HC1+ HNO 235u Total Cd Cr Cu and Pb extracted with 3+ 1 Cd Ni Pb and Zn extracted from soil with Digestion with HNO alone shown to be adequate for most trace elements but not for Cr and Ni Bioassay technique based upon Cyperus esculentus used to assess potential heavy metal toxicity of sediments prior to dredging and land disposal HF + HNO + HClO,; H3B03 added to complex F- and residue extracted with HNO,; ten major and trace elements determined See Ti ref.9311240 Cu Fe Mn and Zn determined Evaluation of an ICP-MS instrument described Optimization of conditions described for Ag Cu Fe FI slurry sample introduction system described and Tree ring analysis used to date forest fires and assess Total reflection XRF compared with semiquantitative Two techniques compared for As Ba Cr and Pb in Study of uptake from soil by parts of ginseng Rapid determination in the field of heavy metals in Small samples mixed with cellulose or boric acid Fundamental parameter technique used successfully assuming cellulose to balance element formula Samples digested at 170 "C for 2-8 h with Samples ashed at 900 "C with lithium metaborate Mn Pb and Zn evaluated element translocation in wood mode operation of ICP-MS 30 samples contaminated soils described Reference 9312892 9311240 9312892 9313427 9313791 931C889 93/C71 93/C127 93/C252 93167.5 931691 931839 931847 93/c904 9311023 9311050 9311094 9311095 9311 100 9311 103 9311121 9311201 931 1240 9311262 93lC1369 93lC1340 931c1505 931C1582 9311652 9311671 93,4708 9311716 9311741 9311770 Ti Tomato roots stems and fruits AE;ICP;L MS;-;S M S;GD; S MS;--;- U U Soils Soils U Soil Zn Soil AA;-;L A A;ETA; L Soil Various Various Fruits AA;F;L A A;ETAL AE; 1CP;S AE;ICPL Various Various Various Clays Cereals tea leaves AE; 1CP;L Soils sediments Various Various Environmental samples Soil AE;ICP;L AE;ICP;L A A;ETA;L Soil extracts AA,-;L Various Various Various Citrus leaves pine needles Soils AE;ETA;L XRF;-;S MS;ICP;S Various Soils AA;ETA;L Various Various Various Roadside soil AA;F;L MS;ICP;L Plants Sediments AA;-;- Various Soils rocks AA;-;- Various Plants AE;ICP;L Various Various Various Various Tomato plant parts Soil Plant samples Agricultural and food samples Soils AE;ICP;L AE;ICP;L MS;ICP;L AA;ETA;Sl Various MS;ICP;SI MS;ICP;L Various Tree rings Various Spinach MS;ICP;L MS;ICP;S XRF,-;- X RF;-; S XRF;-;S XRF;-;S Various Soils Soil ginseng Soil Various Various Various Various Leaf tissues Leaves49 R JOURNAL O F ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Table 3 (continued) Technique; atomization; analyte form* XR F;-; S Element Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Various Matrix Soils Medicinal plants Forest plants Plants Plants Plants Sample treatmentlcomments Aluminium ring double-layer pellet method used for Standard use of XRF Calibration for 15 elements based on CRMs Samples carbonized then ashed with NH,NO Samples digested with HNO + HCI or HNO + FI system described with programmable dilutions Kale CRM used for calibration in LA-ICP-MS Samples pressed to pellets with cellulose and graphite Evaluation of a microwave-assisted digestion system Determination of leached As Cr Cu Pb and Se Secondary ion MS evaluated for stable isotope 38 laboratories participated in comparison of four Ca Cu Fe K Mn P and Zn H,Oz + HF in closed Teflon vessels and standard additions determinations prior to LA described studies in plant physiology techniques for SRMs Reference 93/1801 9311804 93,4862 9311863 9311932 9312051 9312091 93/21 10 93/2201 9312202 9312294 9312396 9312719 9312739 9312822 931c3030 931c3042 9313292 9313444 93/3489 9313508 9313709 9313820 9313821 93/3824 9313999 9314000 9314075 9314076 9314122 XRF;-;S XRF;-;S XRF;-;S AA;F;L AE;ICP;L AE;DCP;L Leaves MS;ICP;S Leaves MS;ICP;S Phosphatic fertilizers Soils MS;ICPL MS;ICP;L Plants MS;-;S Vegetation AA;-;- NAA;-;S AE;ICP; L XRF;-;S AE;DCP;L Plants Optimization of microwave-assisted dissolution for determination of Ca Cu Fe and Zn described Application of synchrotron radiation for excitation of fluorescence of Cu Fe Pb and Zn described 11 elements found in dry drugs but only Ca Mn Sr and Zn in their water infusions Laser ablation and slurry nebulization compared with HCl + HNO digestion Co Cu Fe and Mn distributions studied in relation to trace-element deficiency problems in livestock Cu K Mn Na and Zn contents measured Algae Plant drugs Soils Soils XRF;-;S XRF;-;S MS;ICP;S,SI,L AE;ICP;L AE;ICP;L Anacyclus pyrethrum roots Plants and soils AA;F;L AE;F;L MS;ICP;L Separation procedures described for isotope dilution ICP-MS determination of Ag Cd Mo and Ni using peak-jump mode Cu Fe Mn and Zn determined on compacted ground samples using synthetic standards in cellulose matrix Analytical procedures used for soil testing in The Gambia described Change in heavy metals in earthworms with distance from road studied Punched disks analysed directly Empirical coefficient method used Trace heavy metals studied as function of distance H2S04 + H202 digestion procedure evaluated and Resins in mesh bags used to extract nutrients and A1 Exchangeable cations extracted with CH3COONH4 Samples digested with HNO in closed Teflon vessels For 18 elements results by ICP-AES and INAA were from main highway found to be satisfactory from advisory soil samples and SrCI added prior to analysis similar Soybean XRF;-;S Soils AAF;L AE;F;L AA;-;L Earthworms Plant leaves Soils Soils Plant tissue Soils Soils AE;ICP;L AE;ICPL AE;ICP;L AE;ICP;L AE;ICP;L Leaves Wood * Hy indicates hydride and S L G and Sl signify solid liquid gaseous or slurry sample introduction respectively.Other abbreviations are listed elsewhere. Digestion with nitric acid is very attractive for plant samples especially if the requirements of ICP-MS are to be met. Goto et al. (93/4076) recommended digestion with HN03 in closed PTFE vessels prior to the determination of ten elements (Al B Ca Cu Fe K Mg Mn P and Zn) in a variety of plant samples by ICP-AES. The digestion took 2 h at 170°C and recoveries were confirmed using three NIST SRMs. For the determination of Cd and Ni in rice plants it has been suggested that digestion with HNO + H2OZ even at room temperature can give quantitative recoveries (93/3194).Laboratories which have elected to invest in ICP-MS may well regard the cost of microwave-assisted digestion as a rela- tively minor extra. Averitt and Wallace (93/2201) used such an approach to digest phosphate fertilizers feed-stuffs and river sediments with ultra-pure HN03 prior to the determination of a wide range of elements by ICP-MS. Sometimes a pre- digestion is used prior to the microwave-assisted digestion step. For example Pennington et al. (93/1158) used a pre- digestion with HN03 + H,02 prior to microwave treatment for 2.25 min in the determination of B in plant materials.50R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 According to Lajunen et al. (93/1932) the choice of acid in microwave-assisted plant digestion depends upon both the type of plant material and the choice of elements to be determined. These workers developed sys tems based upon either HC1+ HN03 or H F + HN03 + HzO,. Their conclusion is important but should come as no surprise to those with experience of the differences in ease of digestion of diverse plant materials. It would be interesting to see the results of extending the rigorous factorial design approach of Mohd et al. (93/2719) to a diverse range of plant materials. It is already clear that optimization of conditions for microwave- assisted digestion requires care knowledge and experience. One of the most attractive features of microwave-assisted digestion is its relative speed compared with conventional digestion procedures.It comes as no surprise therefore to see further attempts at on-line microwave digestion. This approach has now been applied to soils and sludges with slurry concen- trations of up to 2% m/v (93/C36). Kjeldahl digestion for nitrogen determination is very widely used on a routine basis in many laboratories. The procedure results in a solution of ammonium in fairly concentrated H,S04. A closed system ammonia diffusion procedure has been described for separation of the NH4+-N from this matrix into one more suitable for determination of N isotope ratios by MS (93/2985). However the diffusion step takes 6 d. Application offusion methods to plant samples is not particu- larly common generally being regarded as rather labour- intensive.In spite of this Goto and Ninaki (93/1201) have recommended fusion with lithium metaborate at 900 "C and extraction of the flux with HNO for the determination of Al Ca Cu Fe K Mg Mn P Si and Zn in plant materials by ICP-AES. The procedure was validated using a selection of plant SR Ms. 3.2.2. Slurry preparation Less has been published on slurry nebulization over the past year compared with the previous few years although a few examples of applications are included in Table 3. Anyone thinking of applying this approach to soil or rock samples is encouraged to read the short paper by Jerrow et al. (93/2087) who demonstrated that new cation-exchange sites generated as a consequence of ball-milling such samples can have a significant influence upon subsequent slurry behaviour especi- ally if the standard additions method is employed for analysis or if releasing agents or other chemical modifiers are employed.3.2.3. Solvent extraction Novel solvent extraction procedures are relatively rarely pub- lished at the present time partly because well tried and tested procedures are available for most determinations and partly because the excellent sensitivity and selectivity of techniques such as ICP-MS has made them redundant in some labora- tories. Those that are published often involve rather exotic reagents. An AA procedure has been developed for the determi- nation of Se in plants based upon extraction from a bromide medium of an Se-organic compound with hex-1-ene in toluene (93/C933).An acetate buffer at pH 3.5 has been used to extract Sn from soil and the extract was then treated with picric acid and extracted with a crown ether in CHC1 (93/4057). The organic phase was diluted 1 +2 with ethanol prior to analysis by AAS. A solution of 1 -phenyl-3-methyl-4-benzoyl-5-pyrazo- lone in benzene and isopentanol has been used to extract and concentrate REE from acid digests of tea leaves prior to determination by ICP-AES (93/701). Some solvents for example highly halogenated organic solvents are not suitable for conventional nebulization in analytical flame spectrometry. If solvents such as CHCl are used for solvent extraction often back extraction (e.g. into dilute acid) is used to obtain a more suitable solvent for nebulization but this is time consuming.Kojima and Kondo (93/3415) overcame this problem after extracting the APDC Cd complex from acid digests of plant material into CHC13 by using discrete sample (one drop) nebulization of the organic phase. Background correction was necessary to compensate for the change in flame background absorbance. However their procedure was still slow because it involved a pre- extraction of Fe. 3.2.4. Other separation procedures Developments in FI hardware and associated PC software over recent years have rendered automated column separation and pre-concentration techniques much more attractive than hitherto. Recent developments in this field have been discussed in a review with 96 refs. by Ebdon et al. (93/813). Welz and Sperling (93/2121) have described such a system for the determination of Cd Co and Ni in biological materials follow- ing acid digestion.Sensitivity was enhanced 42- to 53-fold. Of-line column-based pre-concentration systems have been described for the determination of Co in plant and other samples (93/2726) and of Bi in environmental samples (93/1125). Columns containing diphenylthiocarbazone immob- ilized on polyurethane foam have been employed to concen- trate Pb from waters and from acidic soil extracts (93/C902). 3.2.5. Speciation studies Interest in speciation in environmental studies shows no sign of abating and indeed appears to be expanding. It is therefore worthwhile to highlight three useful comprehensive reviews of speciation methodology which have been published over the review period.Donard and Martin (93/1261) have presented an account (37 refs.) of the applications of hyphenated tech- niques in general to environmental speciation studies. Hill et al. (93/3219) concentrated in their review upon applications in which chromatography had been coupled to ICP-AES or ICP-MS. The IUPAC Commission on Microchemical Techniques and Trace Analysis (93/2565) has published a very comprehensive account of the determination of As species in environmental and biological samples. The term 'speciation' is used in different ways by different workers. It is most precisely used to mean the identification of the different forms of an element in a solid and/or solution phase and quantification of the amount of the element in each of these forms. However it is also sometimes used to mean the quantification of more loosely defined pools of an element such as plant- or biologically-available forms.While biological assays must be regarded as the most reliable indicators of this pool (93/1103) they are not without their problems and more convenient surrogate procedures are still being sought. A method using cation- and anion-exchange resins in mesh bags appears to be showing considerable promise for a diverse range of nutrient and potentially phytotoxic elements (93/4000). Most of the studies of metal speciation in soils rely upon operationally dejined fractionation procedures. Notionally at least each operation removes (usually sequentially) a suppos- edly discrete fraction for example water-soluble exchangeable associated with organic matter and so on.However small procedural modifications invariably modify results. Such an approach has been applied to the speciation of Al Cd Fe Pb and Ti in soils (93/847) and to the study of Chernobyl-derived "Sr and 137Cs (93/410). An operationally defined procedure has also been applied to the speciation of Mn in tea samples (93/C150). Two speciation studies bused upon chromatographic separ- ations are worthy of mention. The first involved the determi- nation of butyltin species in sewage and sludge by GC-AAS (93/1035). In the second seven As compounds were separated by HPLC prior to on-line detection by FAAS using an Ar-H,-entrained air flame and a slotted-tube atom trap to optimize sensitivity (93/1007). The procedure was applied toJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 51 R extracts of soil samples from a polluted site. Results were compared with those obtained using HPLC-ICP-MS. Over the past few years studies on effects of acid deposition have stimulated an increased interest in the speciation of sulfur. Total S in soils is usually determined by a furnace oxidation system (if sufficiently sensitive) or following wet oxidation. However the element can be fractionated again by an oper- ationally defined procedure into water-soluble adsorbed dilute HC1-labile dilute HC1-soluble pyrite-associated HI-reducible ester-bound and carbon-bonded S (93/3499). The element was determined in each solution by ICP-AES. For the determination of S2- and S 0 3 2 - in soil solution or drainage water an automated procedure based upon continu- ous segmented flow gas-phase sample introduction and cool flame emission spectrometry has been described (93/C88).The sensitivity of the determination could be enhanced by at least an order of magnitude by using NaBH to reduce the species to H,S and introducing the latter to the cool flame rather than SO2. 3.3. Developments in Atomic Absorption Spectrometry Atomic absorption spectrometry is now such a thoroughly tried tested and trusted analytical technique that regular major advances can no longer be expected. There have been some minor developments worthy of mention here mainly in the fields of HG and ETA. Also however Vaughan et al. (93/3510) have coupled a peristaltic pump to a flame AA spectrometer for automatic dilution of samples.Anyone who has often thought of doing this but never quite got around to doing it might like to have a look at their paper. One of the most interesting papers on hydride generation and cold vapour techniques in AAS was a study of the effects of fulvic and humic acids on the determination of organomer- cury forms in freshwaters (93/3625). It was suggested that the acids bind the organomercury compounds. The interference effect can be overcome by treatment of the samples with hydrazine borate. A useful paper has also been published on the determination of Se in plant materials (93/2195). The samples were wet-ashed with HN03 or HNO + HC104 and SeV' reduced to Se" by boiling the sample with 6 mol 1-1 HC1. If a two-channel spectrometer is available then two elements such as Bi and Sb can be determined simultaneously by HG-AAS (93/485). Brindale et al.(93/C32) have described a computer-controlled batch hydride-generator system which allowed exploitation of the lower LODs lower sample require- ment and rapid analysis rate of batch techniques. Hydride generation for sample introduction prior to electro- thermal atomization warrants serious consideration. Trapping hydrides of a range of elements onto a Pd-coated L'vov platform has been shown to be at least 80% efficient (93/3964). The method was shown to work for determination of Sn in orchard leaves and river sediment SRMs. The choice ofchemical modijer for ETA continues to attract attention at conferences (93/C880). Invariably palladium figures prominantly in any cocktail selected.For example its use allows a pyrolysis temperature of 400°C in the determi- nation of Hg in aquatic plants and river sediments (93/412). Introduction of slurry samples of soils and plant materials to electrothermal atomizers has again been reported at confer- ences (93/C111 93/C1369). Ultrasonic dispersion can be used to ensure that sub-samples are representative (93/C111). The approach is especially attractive for rapid screening of elements such as Pb (93/C111) although satisfactory results for food and agricultural CRMs have also been reported for Ag Cu Fe Mn and Zn (93/C1369). 3.4. Developments in Atomic Emission Spectrometry As might be expected most of the significant developments in the AES field have been associated with ICP-AES and especi- ally with aspects of sample introduction to the ICP.A powdered sample introduction device has been described by Lin et al. (93/675). Two enclosed electrodes were used to generate an arc above the induction coil and enhanced emission intensities were observed when the sample was introduced at 0.4 mg s-'. A single set of synthetic standards could be used to determine a range of elements in rice flour wheat flour and tea leaves. An FI-based system has been described for automated pro- grammable dilutions and standard additions for the analysis of plant digests by ICP-AES (93/2051). The system was claimed to be very versatile allowing exploitation of merging zones zone sampling intermittent flow sequential injections zone trapping and stopped-flow.Although not often reported to require special treatment memory efects in spray chambers and torches can be a problem in some determinations. Goto et al. (93/1202) found it necessary to nebulize 1 % NaOH for 1 min after each sample to overcome such effects when measuring hot-water soluble B in soils. Using this approach they were able to achieve an LOD for B in soil of 0.02 mg kg-l. Most users of ICP-AES are fully aware of the spectral interferences associated with wavelengths commonly used for the determination of most elements and apply appropriate corrections using suitable software if an alternative wavelength is not available. However chemical separation of or from interferences prior to determination may be necessary in some severe instances.A thiol-cotton fibre column has been used to separate Au from alkali and alkaline-earth metals and iron and other matrix components of sludges and soils (93/762). After pre-concentration and separation the results obtained at 242.795 and 267.595 nm were in agreement a useful if not totally unequivocal test for identifying residual errors. Electrothermal vaporization systems are sometimes used for enhancing the sensitivity of determinations by ICP-AES. For example a tungsten coil ETV system has been used for the determination of REE and other elements in rice samples (93/3242). In most instances the LODs for REE by ETV-ICP- AES were better than the corresponding values by ETAAS. Not surprisingly however in the determination of Cd and Pb in environmental systems using a tungsten boat ETV system a chemical modifier such as (NH4),HP0 had to be employed Two interesting developments in furnace atomic non-thermal excitation spectrometry have been described.In one Hg from foliar or sediment samples was concentrated in situ in a platinum gauze-lined graphite tube using a cold vapour tech- nique (93/1644). The absolute LOD improved more than 7-fold compared with CVAAS and 4-fold compared with CV-ETAAS. The other reported potentially serious problems from structured backgrounds when FANES was used for simultaneous multi-element analysis of environmental samples in spite of the use of background correction by wavelength modulation (93/1023). (93/3359). 3.5. Developments in Atomic Fluorescence Spectrometry and Related Techniques The writer sometimes tends to think of AFS as a technique which is dead but refuses to lie down.The truth is that for some determinations especially the determination of mercury where the CV technique provides virtually zero background the potential sensitivity is so good that AFS will remain the technique of choice in some laboratories. Swift and Campbell (93/3714) commented that the sensitivity of the determination of Hg by CVAFS ultimately appeared to be limited by the purity of the reagents but were able to use the method on environmental samples at the ng 1-' concentration level. Ju and Zhang (93/687) used CVAFS for the selective determi- nation of HgS in soils the compound being extracted with saturated Na2S solution. Phosphorus in plant samples has been determined by laser- excited atomic Juorescence spectrometry using ETV (93/2074).52 R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Determination by monitoring the laser-excited molecular flu- orescence of phosphorus monoxide was described in the same paper. While undoubtedly such studies are academically inter- esting it is difficult to envisage such an approach ever being widely used on a routine basis. 3.6. Developments in Mass Spectrometry The growing maturity of the technique has resulted in the appearance of three reviews of environmental applications of inductively coupled plasma mass spectrometry over the past year. Two of these are general and introductory accounts of the use of ICP-MS in environmental monitoring (93/998; 93/2323); the third assesses the suitability of the technique for the determination of noble metals in plants rocks and waters One of the prime advantages of ICP-MS over most of the other techniques considered so far in this section is that it allows the direct determination of element isotopic concen- trations or isotope ratios. High-resolution instruments allow determination of isotope ratios with the sort of precision required by environmental scientists because of the low back- ground achievable (93/C88 1).Stable isotope enrichment using loB and "B enrichment has allowed the study of uptake and translocation of B by intact plants and in isolated protoplasts and leaf and stem tissue (93/3509). Cox et al. (93/1008; 93/C1295) have devised procedures for the measurement of the long-lived radionuclide 12'1 in vegetables by ICP-MS.The element was transferred into the plasma either using ETV (93/C1295) or using a vapour generation technique based upon I,. These sample introduction techniques were essential to attain the necessary sensitivity. The advantages of isotope dilution mass spectrometry have been outlined by Beary and Paulsen (93/3444). The ICP-MS can be used in a semiquantitative mode to identify any potential interferences and the information obtained used to select separation procedures. The latter do not need to give quantitative recovery if an ID technique is employed. In spite of all the advantages of ICP-MS in terms of sensitivity and selectivity the need in most laboratories for sample dissolution remains a problem.As a consequence there has been considerable interest in the use of laser ablationfor sample introduction to the plasma. For soils pressed polyethyl- ene disks can be used as targets (93/1050). Alternatively cellulose+graphite (1 + 1 ) can be used as a binder material for a range of environmental materials including foliar and geo- logical samples (93/2110). Methods can be tested using CRMs or by comparison of results with those obtained following acid digestion (93/C3031). For plant samples calibration may be based upon the use of SRMs if these are thought to be the most appropriate standards (93/2091). An alternative approach is to use slurry nebulization (93/C1505). Glow discharge mass spectrometry has not found widespread application in the environmental field.However a paper has been published on the determination of 235U 238U isotopic ratios in soils (93/3427). The total analysis time was only 10 min for each cathode and the precisions of measurement for two samples were +_ 5.70 and f 5.75%. Thermal ionization mass spectrometry has a number of devotees in the environmental field especially because of its capabilities for precise isotope ratio measurement. In a study which compared ID-TIMS and ID-SIMS for the determi- nations of U and Th concentrations in soils the precision of TIMS was about six times better (93/2892). When applied to the measurement of Mo in plant materials always a difficult determination because of the low concentrations present ID-TIMS gave a precision of better than 3% (93/2940). (93/3497).In spite of the benefits of TIMS other mass spectrometric techniques are sometimes strongly recommended. For example SIMS has been advocated as an excellent tool for nutrient tracer studies in plant physiology (93/2294). Copper in small numbers (10-100) of isolated plant cells has been measured using RIMS (93/2894). The latter paper was optimistic about the possibility in the near future of detection of elements such as Cu in single isolated cells. 3.7. Developments in X-Ray Fluorescence Spectrometry Applications of XRF in soil and plant analysis are not uncom- mon and as a consequence it is encouraging to see a review of advances in X-ray fluorescence spectrometry in environmental science (93/1654). Most development still appears to be associ- ated with calibration techniques especially for plant analysis. In a study of the effects of acid deposition on forests calibration using a selection of SRMs was thought to be the most appropriate procedure (93/1862). The method was rapid and the results precise and reproducible for Al Ca C1 Cu Fe K Mg Mn P Pb S Si Sr and Zn.Similarly SRMs were also used for calibration purposes for the indirect determi- nation of glucosinolate in rapeseed samples from total S contents (93/2740). An alternative approach to the analysis of plant samples by XRF involves preparation of synthetic standards. For Cu Fe Mn and Zn in soybean petioles cellulose with appropriate amounts of determinands incorporated in solution was found to be suitable (93/3489). In another study on the analysis of small leaf samples mixing with cellulose was found to be superior to mixing with boric acid (93/1741).The method worked even on samples smaller than 40 mg. Cellulose has been shown to be an appropriate formula to specify when conducting quantitative XRF analysis of leaves using the fundamental parameter technique which requires no standards for quantitative analysis (93/1770). The fundamental parameter technique has also been recommended for the analysis of soils in the field for their heavy metal contents with portable XRF equipment (93/1716) For the assessment of plant nutrient status by XRF in fertility diagnosis 13 mm diameter corn plant leaf disk samples have been found to be adequate and their use obviates the need for grinding of samples and greatly facilitates drying (93/3820).The leaf punch disks were randomly placed in the pellet die. An interesting report has been published on the use of high- resolution XRF for sulfur speciation (93/1665). The technique which was applied to peach leaves soil tea and coal used a computer program to resolve spectral peaks by the least- squares curve fitting method. Comparison of the results obtained with those from other methods showed satisfactory agreement. Finally in this section total rejection X-ray fluorescence spectrometry continues to attract attention and has been shown to give good to satisfactory results for a range of elements in biological reference materials (93/1652). Toelg and Klockenkaemper (93/3373) have compiled a useful review of this topic based upon 137 refs.3.8. Laser Microprobe Mass Spectrometry Laser microprobe analysis is potentially a very powerful tool for the investigation of surface chemical effects in soil and plant systems. It has been applied in a study of A1 and Pb in the fine roots of Norway spruce and in their ectomycorrhizal sheaths (93/2660). Cellular and partly sub-cellular localizations of A1 and Pb were identified. In fine roots with secondary structure localization of A1 was limited to the peripheral cell layers.JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 4. ANALYSIS OF GEOLOGICAL MATERIALS 53 R 4.1. Introduction The analysis of geological materials during the past year has been dominated largely by the use of one particular technique inductiuely coupled plasma mass spectrometry.This is readily apparent in Table 4. It is clear that ICP-MS has now 'come of age' and is established as a routine efficient and robust analytical technique in much the same way as ICP-AES was during past decades. The main advantages of ICP-MS its ability to provide isotopic data (93/C15) and superior sensi- tivity to ICP-AES often result in tedious chemical separations being unnecessary. The limitations imposed by the amounts of dissolved solids and solvent that can be tolerated have led to investigations into alternative methods of sample introduction e.g. LA (93/3102) or FI (93/C1426). A comprehensive review on the role of ICP-MS in exploration geochemistry cited 116 refs. (93/1925) while one concerned with the determination of noble metals listed 39 refs.(93/3497). Two reviews presented at conferences on analysis by ICP-MS dealt with mining and mineral exploration (93/C918) and the geochemistry of waters rocks and minerals (93/C1319) while a review on the determi- nation of trace elements in coal quoted 10 refs. (93/2935). 4.2. Sample Preparation 4.2.1. Solid sample introduction The analysis of geological samples following laser ablation of solids has been reported frequently during the past year especially in ICP-MS. An investigation into the application of this technique to the analysis of silicates used both pressed powder discs and fused glasses for sample preparation (93/C31). Calibration was linear over 4 orders of magnitude. Both trace and ultra-trace elements were determined with LODs better than XRF and comparing favourably with those of instrumental NAA.A similar approach was used to deter- mine Cu Pb Sn and Zn in carbonates (93/1001 93/1048). Calibration was achieved by addition of elemental standard solutions to a carbonate powder base enabling low concen- tration standards (down to 10 pg g-' of addition) to be produced. This technique obviates the need to weigh very small amounts of solid oxides. Three dificult matrices analysed by LA-ICP-MS were U308 monazite and zircon. Twenty-three impurity elements in U30 were determined using a matrix-matched single point cali- bration method (93/1003). Detection limits reported ranged between 1 pg g-' and 10 ng g-' with an RSD of 8% when using 234U as an internal reference isotope. A conference presentation by Chenery and Cook (93/C1921) reported the development of a high-resolution LA microprobe.This enabled micrometre scale zoning of REEs in monazite to be achieved determinations being made on a 5 pm crater size. Five zircon RMs were analysed for Hf Th U Y and REEs (93/1004 93/1054). Results obtained from pressed powder pellets and fused glasses were compared with those obtained using a fusion technique with fused glasses showing the best agreement. There is always considerable interest in the determination of platinum group elements (PGEs) and gold in geological mate- rials. Direct analysis of the NiS bead produced by normal fire assay techniques using LA-ICP-MS has the advantage of avoiding a chemical dissolution step which might introduce elemental losses (93/C982 93/C1314).A more fundamental study of LA processes involved the collection of particles produced after ablation of olivine and pyrite and their subsequent analysis by EDXRF and SEM. Results showed that the ablation products had undergone a complex heating regime giving populations with different chemical compositions (93/1010). Techniques using slurry nebulization have been the subject of two interesting investigations with analysis by both ICP-MS and ETAAS. The rapid determination of PGEs and Au in solid samples has been studied using an acidified (HCI + HNO,) dispersing agent ( Na2P40,) which ensured the suspension of samples during grinding together with partial digestion of the noble metal bearing minerals (93/C981 93/C13 14 93/3097). Detection limits were between 0.02 and 0.1 ngml-' when Au Ir Os Pd Pt Rh and Ru were determined by ICP-MS in five RMs.The determination of elements of various volatilities in coal ash and sludge samples used ultrasonic homogenization of the powdered sample with analysis by ETAAS using standard programmes and chemical modifiers (93/C1366). Two studies into the attainment of optimum conditions for the analysis of slurries by ETAAS have been reported. In the first slurry preparation techniques instrumental operating conditions and calibration strategies were investigated (93/2200). In the second the effectiveness of preparing sediment slurries by impacting beads mechanical means and ultrasonic homogenization for the determination of Cd and Pb was evaluated. Ultrasonic homogenization produced the best results (93/3113). The analysis of single fluid inclusions has been made possible using LA.Investigations into element ratios (Ba Ca K Li and Mg ) of single inclusions in halite used synthetic inclusions containing standard solutions for validation of LA-ICP-AES analyses (93/1000). Chenery et al. (93/C1322) used a high- resolution LA microprobe coupled to an ICP-MS instrument to study single fluid inclusions. Their technique enabled trace elements to be determined down to a few pg ml-' in a 20 pm diameter inclusion (93/C1322). A completely different approach was adopted when ICP-MS was used to analyse concentrated brine solutions obtained from large single fluid inclusions present in halite crystals. A conference presentation compared the options of FI analysis and time resolved aquisi- tion (TRA) (93/C1327).The TRA mode proved to be more convenient to use and provided better LODs. Analysis of SRM NIST 1643c gave excellent agreement with certified values. 4.2.2. Decomposition with acids The determination ofgold in geological samples using a complex two-stage decomposition procedure was reported (93/1041). After roasting the sample at 700 "C followed by treatment with HBr + Br the liberated Au was extracted into IBMK. Further treatment with HC1+ HN03 coprecipitation with K,TeO dissolution of the precipitate in toluene and back-extraction of Au into HCl+HNO was followed by determination using AAS. A simpler procedure used an acid decomposition with HF + HNO + HC104 followed by HCl + HNO to ensure complete dissolution of gold-bearing minerals (93/1914). The Au was eventually extracted into IBMK and determined by ETAAS.Studies of 26 Japanese RMs gave values for Au which were clearly higher than those obtained from a partial attack using only HCl+ HNO,. A third method used the same initial decomposition procedure followed by addition of 1 ml of HBr + Br (1 + 50). The liberated Au was then extracted into amyl acetate and determined by AAS using the 242.8 nm line (93/3157). Selective decomposition is very useful in the analysis of specific mineral phases. A study investigating natural fluorite used treatment with dilute CH,COOH to remove other Ca containing phases (e.g. calcite gypsum). The fluorite was dissolved with HC1+H3B03 prior to determination of Ca by AAS (93/1169).Another selective extraction scheme used hot alkaline diethylene-triaminopentaacetic acid to dissolve barite associated with carbonate shells (93/3095). The effectiveness of this procedure was confirmed by paired sample studies.54R Table 4 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 SUMMARY OF ANALYSES OF GEOLOGICAL MATERIALS Technique; atomization; Element Matrix analyte form* Ag Rocks and minerals AA;ETA; S1 Sample treatment/commentst Reference 931653 Sample slurried in 5% HNO or 5% HCl + 0.01-0.1 YO TritonX-100 and ultrasonically agitated whilst sampling. Ashing temperature 600 "C and atomization temperature 1600 "C used giving characteristic mass of 1.9 pg (0.1 ngml-') Pb and Zn determined on same samples by polarography Metal preconcentrated from a H3P04 + NaH2P0 + HCl + NH,Br medium on polyurethane foam and eluted with thiourea.Samples atomized from platform inside graphite furnace (Au 1 ng g-' Ag Metals preconcentrated on diphenylthiourea modified foam from an aqua regia extract and re-eluted with 0.2 % diphenylthiourea+O.l mol 1-l HC1 at 100 "C dissolution Pb and other interfering elements with tataric acid; Ag extracted into TBMK. Organic phase atomized from a quartz boat (dolomite and fossilized oyster shells) used as Ca dietry supplements compared A1 and Si contents used to estimate the ash content and gross calorific value FI sample introduction used. Recovery of 100% and precision of 3% obtained for CRM Samples dissolved in aqua regia. FI sample introduction used with an analysis rate of 60 h-'.10% KI 5% ascorbic acid and 5% thiourea used to minimize interferences (As 0.2 Bi 0.2 Sb 0.2 pg g-l) Samples decomposed by acid digestion for 2 h at 100°C or fused in alkali for 0.5 h at 900°C. Tartaric acid used to eliminate interferences from Fe and A1 Miniaturized fire assay and cupellation procedure used to preconcentrate Au from 10 g of sample into 1 mg of Ag. Bead arced in graphite electrode with 9 mg of Os-Sb alloy (0.1 x loW9 g Pd and Au 1 ng g-'1 Samples ground to >200 mesh before Sample dissolved in HNO + H,S04 + HF masking Alumino-silicate content of natural materials 0.2 x 10-9 g Pt) Sample dissolved in H2S04 + HNO + HClO (9 + 0.2 + l) organics removed by heating and sulfides by HNO + KClO,. NH4HF2 used as solubilizer and NaCl + Br + HC1+ HNO used as cold extractant.Au preconcentrated on foam plastic and eluted See Ag ref. 931718 See Ag ref. 931730 Au content of different phases analysed; extractions with 0.5% I 1% NH,I 1% HClO Br +methanol 1 + 1 HCI + SnCl used to determine exposed Au Au in carbonate Au in sulfide minerals Au in limonite Au in pyrite and Au in silicates Lead button fire-assay used for preconcentration ( 5 Samples roasted between 450 and 700 "C according to organic and sulfide content and digested in aqua regia before preconcentration on sulfhydryl cotton fibre. Gas chamber profile electrodes used with sample in a liquid NH,I spectrochemical buffer Roasted sample treated with HBr+Br mixture and extracted into IBMK. IBMK extract combined with residue and attacked with HCl+ HNO (3 + 1).Au precipitated with K tellurite in SnCl solution. Au extracted from precipitate into toluene and back into aqua regia Samples digested with aqua regia + HF followed by extraction with IBMK. 26 samples analysed ng g - 7 AA;F;L AA;ETA;L Ores Geological samples 931656 931718 AA;ETA;L 931730 Geological materials AA;F air-C,H,;L AA;F air-C,H,;L 9314065 93/4066 Ag ores Ores A1 Carbonate deposits XRF;-$ 93/1776 XRF;-;S AA;Hy;L AE;ICP Hy;L A1 As As Coal Sediment and fly ash Geological samples 9312842 93/C 106 93 f686 As AU Silicate rocks Geological samples 9311272 93/648 AE;ICP Hy;L AE;d.c. arc;S A U Ore 931660 Au Au Au Geological samples Geological materials Geological materials AA;ETA; L AA;ETA;L AA;ETA;L 931718 931730 931731 Au Au Gold deposits Geological materials AA;F;L AE; d.c.arc;L 93/C956 93/1031 AU Geological samples AA;F air-C2H2;L 93/1041 Au Geochemical SRMs A A;ETA; L 9311914JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 55 R Table 4 (continued) Technique; atomization; analyte form* XRF;-;S Element Matrix Au Ore samples Sample treatment/commentst Reference Ore roasted for 1.5 h at 570"C cooled and leached with Fe2( S04)3 +thiourea + H2S04 (pH 0.5) for 3 h. 0.2 g of activated C added to 350 ml of leachate then filtered and analysed (40 pg kg-') 10 g of sample roasted for 1 h digested in 25 ml of aqua regia taken to near dryness taken up in 5 ml of aqua regia filtered (washed with HCI) and Au absorbed on 0.2 g of foam plastic. Au extracted in 25 ml of 3% thiourea+ 1 ml of 400 mg 1-' Fe 5 g of sample roasted at 650°C for 1 h residue digested in 25 ml HN03 +20 ml HF + 7 ml HClO followed by aqua regia.Final solution treated with HBr + Br2 and extracted with amyl acetate Check on the accuracy of a field portable anodic stripping voltammeter Sample digested in HCl and Br for 24 h Au coprecipitated with Te dissolved in toluene and re-extracted into aqua regia. No heating required for method 9312023 9313136 Preconcentration on TOP0 impregnated resin Powdered sample mixed with NaCl + ZnO + SnO Samples ashed at high temperature followed by buffer microwave-assisted digestion in HF faqua regia (1+1) prevent volatalization of B and separated by ion- exchange chromatography. Cs,BO,+-graphite method used. B isotopic ratios measured B isotopic ratios measured from B02- negative ions formed in the presence of La(NO,) activator.100-1000 times more sensitive than sodium or caesium borate methods Samples fused in a mixture of GeO Li2B407 Li2C03 and La203 Effect of additional cation-exchange surfaces formed during slurry preparation on the success of using the standard additions technique investigated Sample purified to allow only Ba attached to the Ca lattice to be measured. Ba determined by ICP-MS with ID Ca by flame AA. Ba:Ca ratios used as indicators for past changes in deep ocean circulation patterns Samples prepared by (i) beryl fused with NaF treated H2S04 and heated to remove F-. Residue dissolved in 3% HC1. (ii) Silicates digested in HN03 + HF then HN03 + H2S04 with evaporation to dryness between additions and finally taken up in dilute HCl Sample digested in HC1+ HF with mannitol to See As ref.931686 After irradiation of sample halogens were separated from the matrix by pyrohydrolysis in the presence of V,05. F was determined by ion-selective elect rode and 214Pb Accelarator MS used to measure I4C 13'Cs "OPb Accelarator MS used for radiocarbon dating See Ba ref. 9312018 See Ba ref. 9313095 Au Ore AAF;L AU Geological materials AA;F;L 9313 157 Au Au Geological samples Geological materials AA;ETA;L AA;-;- 9313494 9313922 AU B Ores Polymetallic nodules AA;F;L AE;d.c arc; S 9314 123 931732 B Coal ash AE;ICPL 93 f 1929 B Rock M S;thermal ionization;L 9312248 M S;thermal ionization;L B Borate minerals tourmalines and carbonatites 9312250 Ba Ba Baryte Barytes XRF;-;S 9312018 9312087 AA;F N20-CZHz;L Ba Aragonite coral skeletons AA;F;L MS;ICP;L 9313095 Beryl and silicate rocks AE;ICP;L 93/31 55 Be 931686 93/19 17 Bi Br Geological samples Geochemical SRMs AE;ICP Hy;L INAA;-;L C Lake sediment MS;-- 9312481 9312620 93/20 18 9313095 C Ca Ca Alluvial sediments Baryte Aragonite coral skeletons MS;-;- XRF;-;S AA;F;L AAETA;L M S;ICP;L Samples digested in HN03 or aqua regia.ASV also used for determination Samples prepared in 5% HN03 and homogenized with an ultrasonic probe; PdC12 used as a chemical modifier and samples atomized from a L'vov platform See Br ref. 93/1917 Quinoxalin-2,3-dithiol used for the precipitation and See C ref. 9312481 Powdered solid placed in miniature graphite cup sorptive separation of Co and Ni inside the graphite tube atomizer.Ni( added as chemical modifier. Results agreed with those of analysis of same samples prepared as solutions (Cu 3.6 pg Mn 2.6 pg) 9312179 93/3113 Cd Phosphorites Cd Sediment A A;ETA;L 9311917 9313893 c1 c o Geochemical SRMs Co-Ni ores INAA;-;L XRF;-;S c s c u Lake sediment Quartz MS;-;- AA;ETA;S 931248 1 93170256R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 Table 4 (continued) Technique; atomization; analyte form* AE;ICPSl Sample treatment/commentst 02-H2 flame sample introduction system used for slurries < 2 pm. Significant memory effects observed (Cu 0.3 Mn 1 Zn 1 mg 1-') Ultrasonic nebulizer used with a condenser and H2S04 dessicator to remove solvent (0.008 pg ml-I) Fe complexed with salicyaldehyde guanylhydrazone in IBMK Samples digested in HNO,; HC1 and KI added and Ga extracted as chloro-complex into IBMK.KI prevents the back extraction of Fe (50 ng g-') Hydride produced in FI manifold separated with a membrane gas-liquid separator and swept with Ar into Pd coated graphite tube at 600°C. Determinand atomized at 2500 "C. (0.004 ng ml-' for 4.5 ml of sample) See As ref. 9311272 Hydride formed in a FI manifold and collected on a Pd coated graphite furnace at 400 "C and subsequently atomized at 2500 "C (0.004 pg 1-') isotope ratio meaurements made Pyrolosis temperature of 400 "C and atomization of 1000 "C used. NaCl interferences eliminated by using a purge gas of 95% Ar + 5% H2. (Characteristic mass 0.1 ng) Speciation of Hg carried out by extracting organic Hg with CHCl and back extration with Na2S20 mercury(I1) oxide with 0.05 mol 1-' H,SO and mercury( 11) sulfide with 1 mol 1 - HC1+ 3% NaCl in the presence of CuC1.HgS selectively extracted with HNO and saturated Na,S Three acid decomposition procedures using HNO + KMnO HNO + H2S04 + KMnO or HNO + NaCl gave comparable results Method used to investigate the temperatures at which Hg released from the samples Used to study the relationship of Hg bearing rocks to oil deposits See A1 ref. 9311776 Metals preconcentrated into Au and Ag beads by fire assay before introduction into the plasma by LA Samples decomposed in H2S04 + H202 (1 + 3) separating determinands from the U matrix on a strong basic anion-exchange column Procedure for efficient extraction of Hf described 15 pg of Pd sufficient for 40-60 determinations.Ca found to interfere Sample roasted at 650 "C; chlorite magnesite muscovite and serpentine dissolved in boiling 1 + 1 HCl. Residue containing talc dissolved in HF + HClO or KOH. Talc content estimated from Mg content See Cu ref. 931702 See Cu ref. 9313391 Acid digests and interstitial water analysed. Alpha N-benzoyl-N-phenylhydroxylamine dissolved in spectrometry used to measure U content CHCl as an extractant for samples digested in HF+HCl. Standards made up in extractant + pentanol Reference 9313391 9313550 9311230 9312 133 93/C153 9311272 9313227 93/C253 931412 El em en t Matrix c u Marine sediment c u Ore samples AA;MIP;L AA;F;L A A;ETAL Fe Magnesite Ga Iron meteorites Ge Geological materials AA;ETA;G Ge Silicate rocks Ge Geological SRMs AE;ICP Hy;L A A;ETA;L Hf Geologic matrix MS; t hermal AA;ETA;L ionization$ Hg River sediment and coal fly ash Sediment samples 931549 AA;cold vapour;L Soils and river sediments Sediments 931687 9311273 AF;cold vapour;G AA;-;- Synthetic Hg minerals AA;ETA;L AA*-*- > Y INAA;-;L MS;ICP;S AA;F;L 9313283 Jurassic rock samples 9313517 I Ir Geochemical SRMs Geological materials 9311917 93/C1570 K Uranium concentrates 9311274 Li Mg Fluorite materials Complex ores AE;F air-C,H,;L AA;F;L 93J476 93/64 Quartz Marine sediment Marine sediments AA;ETA;S AE;ICP;L AA;ETA;L MS;ICP;L AE;ICP;L Mn Mn Mo 931702 9313391 93/C 1 6 1 7 Mo Silcate rock 9313 3 75 Uranium concentrates Carbonatite hosted minerals AA;F;L AE1CP;L See K ref.9311274 Diode array detector used for simultaneous aquisition of signal and background for multi-line spectra Procedure checked against INAA analysis See Mo ref.9313375 Ni continuously precipitated from sample solution (pH 4.4-5.5) with 1-nitroso-2-napthol and collected on 0.5 pm stainless-steel filter. Precipitate dissolved in ethanol. Masking agents for removal of interference effects from other metals Na Nb 9311274 93JC20 Nb Nb Ni Geological materials Silcate rock Rock AE;ICP;L MS;ICP;L AA;F air-C,H,:L 93/C892 9313375 93/c122JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 57R Table 4 (continued) Technique; atomization; analyte form* AA-;L Element Matrix Ni Ores Ni Co-Ni ores 0 Magnetites 0 s Molybdenite Sample treatment/commentst Fe interference eliminated by matrix matching See Co ref.9313893 d i 8 0 measured in 11 crystals at increasing distances 0 s purified by distillation after microwave-assisted standards from the magnetite grain boundary acid digestion with K2Cr207 as oxidizing agent. ID calibration used and Re-0s age of sample determined Samples prepared by direct acid digestion followed by anion-exchange separation of Re or fire assay preconcentration and direct aspiration. 0 s introduced into the plasma as Os04 for both sample preparation procedures the range 2-5000 mg kg-' determine Pb at 220.35 nm line in the presence of line overlap from high levels of A1 determine the age of the samples Samples digested in HNO,+HClO,. P determined in Dynamic background correction algorithm used to 9 232Th and 238U measured and used to 207pb 206pb See Cd ref.9312179 See C ref. 9312481 See Cd ref. 93/31 13 See Au ref. 931648 See Ir ref. 931C1570 See Au ref. 931648 See Tr ref. 93lC1570 High-sensitivity method able to detect 10' atoms per sample Rb Sr ratios measured using direct tube excitation with Ag anode X-ray tube and Ag foil primary beam filter to optimize peak to background ratios Distributions of REEs measured by LA with crater sizes of 20 pm. Results compared to EPMA data AA measurements made in axially-viewed power modulated Ar ICP with time gated data aquisition. Sample digested in HF + HNO + HCl in closed PTFE vessel. Analytical lines selected to minimize spectral interferences. chromatography Different methods compared including ion Reference 9313133 9313893 9313493 9311033 9311934 931645 931c952 9311920 9312179 9312481 9313 1 13 931648 93lC1570 931648 931c1570 9312979 93/C24 93/35 93/c213 931757 93/c917 9 3/29 64 9 3 /C9 6 5 93lC1321 9311915 9312 1 98 XRF;-;S MS;ionprobe;S MS;ICP;L 0 s Geological materials MS;ICP;L P Pb Sediments Geological samples AE;ICP;L AE1CP;L Pb Uraninite concentrates MS;ICP;L Pb Pb Pb Pd Pd Pt Pt Pu Phosphorites Lake sediment Sediment Geological samples Geological materials Geological samples Geological materials U ores AA;ETA;L AA;ETA;L AE;d.c.arc;S MS;ICP;S AE;d.c.arc;S MS;ICPS MS;-;- MS*-+- 3 Rb Silicate rocks XRF;-;S REE REE REE Monazite and clinopyroxenes Refactory materials Phosphorite deposits MS;ICPS AA1CP;L AE;ICP;L REE Geological samples INAA;-;S AEDCP;L AE;ICP,L MS;ICP;L MS;GD;S Powdered samples mixed with high-purity Ag or Cu and formed into a pin electrode for sputtering.Samples digested in acid and analysed directly without separation or preconcentration Laser ablation microprobe with a resolution of 5 pm used to measure REE profiles; results compared with those of EPMA analysis of the same samples Sample finely ground and and fused into a glass bead. Results compared well to data obtained using ICP-AES and INAA 0.5 g of sample decomposed in 190 ml of HCl and taken to dryness residue taken up in 4% HCl. Determinands preconcentrated on Dowex HCR-W2 Dowex-SOW KRS-8p or Bio Rad AG-SOW resins and eluted with 6 mol I-' HCl. Ce Er Eu Gd La Nd Sm and Y determined Samples prepared as REE acetylacetonates REE REE REE Rocks Ores Monazite MS;ICP;L MS;ICP;S REE Gabbro SI M S;-; S REE Geologcal samples AE;ICP;L REE MS;electron impact; S MS;ICP;L MS;ICPL 9312352 Geological samples Development of methods discussed 0.1% rock solutions gave precisions of 1-7% with good agreement with certified values Investigation of the influence of matrix structure on secondary ion signals Relative ion yield for both conventional energy filtering and specimen isolation mode reported AF emission spectra of three samples containing 226-867 mg kg-' total REE.Excitation by UV and visible lines of an Ar ion laser and spectra recorded by a Raman microprobe spectrometer 9312361 9312430 REE REE Minerals and ores Geological SRMs Natural minerals and glasses SIMS;-;S 9312469 REE 9313094 REE Amphiboles and clinopyroxene Fluorite SIM S;-$ REE AF;laser excitation$ 9313 10058 R Table 4 (continued) JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Technique; atomization; analyte form* AE;ICP;L Sample treatment/commentst Reference Element Matrix REE REE ores and concentrates Samples fused with Na202 in an Ni crucible leached in H20 diluted in HCl and precipitated as oxalates at pH 1.7. Precipitate dissolved in HN03. Method development described Sample digested in HF + HN03 + HC1 and digest either analysed directly passed through an anion- exchange column to remove Fe or through a cation-exchange column to remove Al Ca and Fe Samples digested by acid attack in a microwave oven or by fusion with Li2B40,. REEs separated on anion-exchange columns. Solution nebulized directly into ICP; REEs precipitated with rhodizonate and tannin for XRF Samples dissolved in acid and preconcentrated by cation-exchange chromatography or coprecipitated with Ca oxalate.Multi-element instrument used with Zeeman effect background correction. Results comparable with those from ICP-MS technique Method developed using doubly-charged odd-mass isotopes. Dy Er Eu Gd Tb Tm and Yb determined (< 15 pg kg-') Spectral interferences minimized by precipitation of Fe Ti and Zr with cupferron Review of different methodologies 9313142 REE ores Geological samples AE;ICP;L 9313 159 9313377 REE REE AE;ICP;L XRF;-;S REE Geological reference materials A A;ETA; L 9313412 REE Silicates MS;ion microprobe;S 9313441 AEICPL REE REE Geochemical samples Rocks 9313527 9313551 IN AA-;- AEICP;L AE;DCP;L MS;ICP;L XRF;-;S AE;ICP;L MS;ICP;S MS;ICP;L MS;thermal ionization;S XRF;-;S Phosphate rock Geological materials Geological materials Bauxite and sediment Digestion method described See Ir ref.931C1570 See 0 s ref. 9311934 ID quantification procedure used 9314012 93/C1570 9 31 1934 9311913 REE Rh Rh S SRMs S Rocks Vacuum sample cell for powder eliminated need for Samples prepared by Eschka digestion. Method pressed powder pellets or fused beads found to be more rapid than standard Ba(SO,) precpi tation method See As ref. 931686 See REE ref. 93/3412 9311994 AE;ICP;L S Coal 93f2712 Geological samples Geological reference Geochemical samples Phosphate rock Geological samples materials AEICP Hy;L AAETA;L Sb sc 931686 9313412 sc sc Se AE;ICP;L AE;ICP;L AA;F;L AA;ETA;L AE;ICP Hy;L MS;Laser INAA;-$ microprobe;S XRF;-$ XRF;-;S A A;ETA;Sl See REE ref.93/3527 Digestion method described Hex-1-ene used to extract and preconcentrate Se. Use of toluene as diluent for hex-1-ene and a bromide medium found to accelerate the extraction process See As ref. 9311272 Mineral network structures studied 9313527 9 3/40 1 2 93lC933 Se Si Silicate rocks Silicate minerals 931 1272 931635 Si Si Sn Carbonate deposits Coal Geological materials See A1 ref. 9311776 See A1 ref. 9312842 Slurry sample atomized from an autoprobe system. Tributyl Sn determined by acetic acid extraction Aqueous standard calibration used hydride generation with cold trapping followed by GC separation before quantification Organotin compounds determined after purge and trap boiling-point separation Hydride produced by FI manifold trapped on Pd coated L'vov platform at low temperature before atomization.Other hydride forming elements examined (7 ng ml-' for 10 ml) HPLC using tropolene in toluene as eluent used to separate butyltin compounds prior to detection with on line AA method See Rb ref. 93/24 See Ba ref. 9312018 Sr Th U isotopes measured 9311776 9312842 931491 Sn Sediments AA;Quartz furnace Hy;G 9313635 Sediments AA;-;G Sn 9313643 Sn River sediment SRM A A;ETA;G 9313964 Sn Sediments 9311099 AA;ETA;L Sr Sr Sr Silicate rocks Baryte Gaussberg lamproites XRF;-;S XRF;-;S MS;thermal MS;thermal ionization;S ioniza tion;L 93/C24 9312018 9312252 Sr Geological materials Recent chromatographic method for the isolation of Sr from geological matrices evaluated.87Sr '%r measured in 13 SRMs 9312900JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 59 R Table 4 (continued) Technique; atomization; analyte form* Element Matrix Sample treatmentlcommentst Reference Ta Geological materials AE;ICP;L Ta Silcate rock MS;ICP;L Te Geological samples AF;-;L See Nb ref. 93/C892 9 3/C8 92 See Nb ref. 93/3375 9313375 Phosphonate resins amine resins pyridine resins and 931651 acrylate resins investigated for preconcentrating Te from sample matrix. Method using a phosphonate resin (M17) loading in 3 mol 1-' HCl and eluting with H,O described (pg 1-' in the solid) See Pb ref. 93/1920 Samples digested with concentrated HF + HNO + HC104 in closed PTFE vessels; digest evaporated to dryness and taken up in 7 mol 1-' HNO evaporated to dryness again and finally taken up in 2% HNO Sr Th U isotopes measured Th Th Uraninite concentrates Silicate rocks MS;ICP;L MS;ICP;L 9311920 9312 130 Th Th Th Gaussberg lamproites Calcite veins Basalts MS;thermal M$-;- ionization;S 9312252 9312938 9313223 230Th 234U and 238U used to date and give the rate of accumulation of calcite Rapid digestion procedure used.Conventional nebulization and ETA sample introduction methods described (0.5 fg ml- ') Single focusing multi-collector instrument gave 3-5-fold improvement in precision over a counting Solid phase speciation of T1 investigated. Sequential extraction with acetate buffer dithionite buffer NaOH HNO oxalate buffer and NH,OH in CH,COOH See Pb ref. 9311920 Low energy scintillation y counting used to measure See Th ref.9312130 Sr Th U isotopes measured 238U and disequilibrium state MS1CP;L Th T1 Young volcanic rocks River sediments M S; t hemal A A;ETA; L ionization;S 9313496 931637 U U Uraninite concentrates Geological samples MS;ICP;L XRF;-;S 9311920 9311921 U U Silicate rocks Gaussberg lamproites MS;ICP;L MS;thermal ionization$ MS;-;- MS;ICP;L A A;ETA; L MS;ICP;L A A;ETA; L AE;ICP;L 9312130 9312252 U U V Calcite veins Basalts Marine sediments See Th ref. 9312938 See Th ref. 9313223 See Mo ref. 93/C1617 9312938 93/3223 931C1617 See Nb ref. 9313375 See REE ref. 93/3412 9313375 9313412 W Y Silcate rock Geological reference materials Ores AA;F air-C2H2;L Samples digested in aqua regia. 40% Zn determined using 307.6 nm line; interference from SiOz removed by the addition of 1% animal glue See Cu ref.9313391 Effect of operating parameters examined ( 1.2 ls4Eu shown to interfere with 95Zr Multi-element linear regression analysis from slurry ng m1-I) nebulization of the clay used to succesfully predict abrasiveness monmorillonite content and viscosity Geological materials prepared as pressed powder discs and fused glasses. Q-switched Nd:YAG laser used for ablation. Geological Survey of Japan standards JB-la JB-2 and JB-3 analysed Mn02-Fe203 coatings of pebbles from stream beds in Wales analysed for trace metals by LA. Data used to predict presence of mineral deposits. High pressure (8 MPa) microwave digestion method described Development of direct sample insertion with graphite probes discussed. Standard addition and internal standardization used on RMs (leaching with NaOH NaOCl H202 and heating to 400OC) shown to alter chemical composition of the inorganic mineral maximizing the accuracy of analysis discussed.A parameter related internal standard method is proposed to reduce bias due to matrix effects and concomitant analytes Internal standardization used to compensate for volatalization interferences Different methods of removing organic material Strategies of multi-element calibration for Direct sample insertion into the plasma used. 931663 Zn Zn Zn Marine sediment Sediment AE;ICP;L AE;MIP;L 9313 39 1 9313950 9311931 93/C26 Zr Various Rocks China clay INAA;-;S AE;DCP;Sl Various Silicates MS;ICP;S 93/c31 93/C38 Various Pebble coatings AE;ICP;S 93/C91 93/C2 12 Various Various Coal Geological materials AA;-;L AE;ICP;S 9 3/46 1 Various Aragonite AAF;L AE;ICP;L 9 31463 Various Geochemical analysis AE;ICP;S 931534 Various Sediment samples60 R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Table 4 (continued) Technique; atomization; analyte form* Reference Sample treatment/commentst Matrix Element Review with 15 refs. 931619 Al Bay Be Cay Ce Co Cr Cu Fe La Mg Mn Ni 931647 Sample digested in HNO + HF + HC104 in a PTFE 931655 Pb Sr Ti V and Zn determined beaker surrounded by MgO (solid) all tighly sealed in another PTFE container and heated by microwaves. H3B04 not required to neutralize HF. Ba Be Ca Ce Co Cu Fe La Mg Mn Ni Sr Ti V and Zr measured by ICP; K Li and Na by AA Cr Cu Mn Ni Pb and Si determined Robotized slurry sampling method used. Al Cd Coy Various Geochemical analysis AA;-;- Various Vanadium titanomagnatite AE;ICP;L Various Geological samples AE;ICP;L AE;F;L AA;ETASl 93/C880 93/CX90 93lC909 Various Various Various Sediments AA;F air-C,H,;L AA;ETA;L AA,F;L Total element concentrations and concentrations in selectively extracted fractions compared.Cd Co Cu Fe Mn Ni Pb and Zn determined mixture followed by acid degradation with HNO HC104 and HF at 150 "C in a pressure bomb. Cd Co Cr Cu Ni Pb Zn As and Se determined Crushed sample coated with NaCl by evaporation of aqueous solution treated with dry chlorine at 570 "C for 3.5 h. Chlorinated products dissolved in HC1. Au Pt Pd Rh Ru and Ir determined quantitatively Samples ashed at 360 "C with a super-oxidizing Uses in mining and mineral exploration discussed Sediments Coal MS;ICP;L 93jC913 Various Rocks Mining and mineral exploration samples Geochemistry samples MS;ICP;L 93/C918 93/c923 Various Various Recent developments in XRF hardware and trace element analysis fundamental parameter correction programme discussed Use of a wide range of methods discussed XRF;-;S Exploration geochemistry samples AA;ETA;L AE;ICP;L MS;ICP;L XRF;-;S AA;F;S AE;plasma;S 931C925 Various Geological samples Samples ablated with a laser and swept into a flame or gas jet plasma for analysis.Ag Au Bi Cu Pb and Zn determined Aiborne soil particulates electrostatically precipitated directly into the graphite tube atomizer Wavelength dispersive sequential system with pre- calibrated quantitative package able to correct for varying ratios of sample and flux material in fused beads described different element suites described Range of sources and detectors used to determine Wide range of methods for environmental analysis 93/c927 Various Various Various Geochemical exploration Exploration and mining particulates samples AA;ETA;S 93/C929 93/c934 X RF;-; S Lateritic material Mining samples XRF;-;S 93/c935 93/C941 Various Various AA;-;L AEICP;L MS;ICP;L XRF;-;S TXRF;-;S MS;ICP;S Various Various Mineral grains Iron ore Laser ablation sample introduction used; effects of instrument and laser parameters critically evaluated Samples digested in HNO + HC1 residue fused with NaB,04 +Na2C0 and combined.Fe removed 4-methylpentan-2-one. Sn extracted as anionic iodide complex.Zeeman background correction used for ETA Energy dispersive method using excitation with polarized X-rays described. Backgrounds are significantly reduced compared to conventional methods Samples ground to 5 pm using zirconia beads in a polyethylene bottle and supended in Na4P20 dispersing agent containing aqua regia followed by direct nebulization as 2000 pg ml-' slurries. Platinum group elements and Au determined Preconcentration of determinands carried out by NiS fire assay. Laser ablation sampling of fire assay button performed. Platinum group elements Ag and Au determined parameters programme Matrix effects corrected with a fundamental 93lC945 93/C961 AA;F;L AA;ETA;L Various Geological samples Geological materials XRF;-;S 93/C971 93/C981 Various MS;ICP;S Various Various Geological samples Copper ore MS;ICP;S XRF;-;S 9 3 /C9 8 2 93/c997JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Table 4 (continued) 61 R Technique; atomization; analyte form* AE;ICP;L Element Various Various Various Various Various Matrix Single fluid inclusions Sample treatment/commentst Reference 93/1000 Laser ablation sampling used; method validated quantitatively by comparison with XRF microprobe analysis. Element ratios for Ba Ca Cu Fe K Li Mn Pb Sr and Zn measured prepared by adding elemental standard solutions to a carbonate powder base. Results for standard materials within 10% of certified values Laser ablation sample introduction used. 23 impurities measured using U30 CRM as a standard. 234U used internal reference isotope Laser ablation sample introduction used.Hf REE Th and Y measured on five SRMs. Solution analysis compared to ablation of pressed powder pellets and fused glasses Laser ablation sample introduction used. Standards 931 9 31 931 Carbonates MS;ICP;S 001 003 004 Uranium oxide Zircons MS;ICP;S MS;ICP;S Minerals XRF;-;S Particles produced from the LA of pyrite and olivine examined by SEM and XRF. Particles found to have been formed by thermo-mechanical shock melting and vaporization FI hydride sample introduction to a two channel non-dipersive AF instrument investigated. Sb As Bi Hg Se and Te determined; FI found to improve LODs over batch sampling (Se 0.035 ng Hg 0.015 ng Te 0.02 ng) Platform atomization utilized; Al Cd Cr Cu Fe Ni and Pb determined simultaneously.Structured background emission found to severely limit capabilities of method. Microwave-assisted digestion of samples used Laser ablation sample introduction used. Standards prepared by adding elemental standard solutions to a carbonate powder base. Results for standard materials within 10% of certified values ETV sample introduction of sample used to separate matrix effects See various ref. 93/1004 High pressure decomposition method described using a mixture of HF + HNO + HClO at 170 "C for 2-8 h. H,BO added to complex F- and dissolve alkaline earth insoluble fluorides. 22 major and minor elements determined 28 minor and trace elments in nine Japanese SRMs determined by a combination of techniques 9311 0 10 Various Geological samples 9311013 AF;ETA Hy;L Various River sediment AE;ETA-hollow cathode discharge;L 9311023 MS;ICP;S Various Carbonates 9311048 Various Sandstones MS;ICP;S MS;ICP;S AA;-;L 9311051 93/1054 9311 121 Various Various Zircons Rock Various Sedimentary rock reference samples AA;-;L AE;F;L INAA;-;S AA;F;L 9311144 Other Ca containing phases separated from fluorite by extraction with dilute acetic acid.Remaining fluorite dissolved in HCl+ H3B03 Review of present methods of analysis with 15 refs. Spectral interference and background effects and compromise plasma operating conditions studied Au Ir Os Pd Pt Rh Ru determined by LA of < 1 g fire assay buttons and by nebulization of samples prepared as < 5 pm slurries suspended in Na,P,O and aqua regia Suggests direct analysis of digested samples could replace the time consuming procedure of fire assay Crushed sample coated with NaCl by evaporation of aqueous solution treated with dry chlorine at 570 "C for 3.5 h.Chlorinated products dissolved in HCl. Au Ir Pt Pd Rh and Ru determined quantitatively Distribution of metals in molecular sub-fractions discussed. Multivariate analysis of data showed organic parameters were coupled to metal data instrument and a simultaneous multi-collector sector instrument. High-precision Pb isotope measurements made Laser ablation procedures for the determination of a wide range of trace elments in geological materials described measure Pb isotopic ratios and REE cnncen tratinnn Laser ablation sampling used on quadrupole Laser ablation and pneumatic nebulization used to 9311 169 Various Fluorite ore Various Various Silicate rocks Sediments AE;ICP;L AE;ICP;L MS;ICPS,SI 9311 198 9311226 Various Geological samples 93/c 13 14 93/C 131 5 93/C 13 16 Various Various Minerals Rocks MS;ICP;L MS;ICPL Various Crude oil and condensates MS;ICP;L Various Geological materials MS;ICP;S 93/c1317 93/C 1 3 1 8 Various Geochemical samples Various Pre-Cambrian sediments MS;ICP;S MS;ICP;L,S 93/C1319 93/C132062 R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Table 4 (continued) Technique; atomization; analyte form* MS;ICP;S Reference 93lC1322 Matrix Fluid inclusions Sample treatment/commentst Laser ablation microprobe with a resolution of 5 pm used to measure trace element composition of inclusions in quartz and fluorite Fluid from inclusion in halite extracted into capillary and diluted with de-ionized water.K concentration over-estimated due to the formation of 23Na'60 homogenization of powdered material suspended in 5% HNO,+O.l% Triton X-100 Samples digested using automated Na20 procedure. AE used for major and some trace elements; MS with FI sample introduction used for REE Au and platinum group metals elemental constituents used to identify the source of mining related pollution. As Cd Cu Cr Ni Pb Sb and Zn analysed Laser ablation sampling used to measure alkaline earth and REEs in oxide growth sequence. Problems arising from standardization using pressed powder pellets of SRMs discussed Relative merits of the use of the two techniques compared Comparison made of the metal content of different sites.Al Ca Fe K Mg Na Sr Ti and Zr determined; Cr Cu Ni and Zn found to be below LOD of the method SRMs diluted with Specpure CaC03. Al Ca Fe Mn P Si and Sr determined (10 Cu Fe Ni Ti and V determined by one wavelength dispersive and two energy dispersive methods; the former gave best precision and accuracy (Cu 55 Fe 50 Ni 70 Ti 40 mg kg-l) Portable instrument used to look for characteristic element patterns which indicate the presence of copper ore Fundamental parameter algorithm used for standardization Review with 11 refs. Samples prepared as slurries by ultrasonic Combination of isotope ratio measurements and Used pressed powder pellet standards made from Element Various Various Various Various Various Various Various Various Fluid inclusions MS;ICP;L 327 3 66 426 93/c 93/C 93/c Coal AA;ETA;Sl AE;ICP;L MS;ICP;L Geochemical prospecting samples Mineral processing spoil MS;ICP;L 93/C 1485 MS;ICP;S 93/C1596 Marine ferromanganese deposits P IGE;-; S XRF-;S PIXE;-;S 9311657 9311702 Coal Tigre river sediments Various Iceland spar Various Polymetallic ores 9311707 9311709 Various Copper ore XRF;-;S 93117'74 Various Rocks XRF;-;S 9311793 9311 8 16 9311829 Various Geological and geochemical XRF;-;S materials materials Various Sulfate-rich weathered XRF;-;S 1.4 standards with a fixed matrix and different concentrations of determinands prepared.Al Ag As Ba Ca Cd Cu Fe Ge K Mg Mn Na Pb Rb Sb Si Sn Sr and Zn determined electrocorundum Fe powder and oxides of the major elements (Al Ca K Na) dilution fusions and calibrated against synthetic standards.Q[ coefficient method used to correct for absorption/enhancement effects Iterative approach to Compton scattering corrections for matrix absorption described Ten standards analysed all elements found to be within the certified ranges apart from Mo and REEs Teflon beakers followed by evaporation to dryness and dissolution in HNO with a final dilution factor of 1000. Ba Hf Nb Pb Rb Sc Sr Ta Th U Zr and 14 REEs determined Standard for rocks prepared by fusing glass Samples fused in graphite crucibles using low Samples dissolved in HF + HC104 in screw top Results for the two methodologies compared Various Rock standard XRF;-;S 9311853 9311857 Various Oceanic floor nodules XRF;-;S Various Various Geological materials XRF;-;S Survey rock standards I NA A;-;S 9311866 9311 91 6 Various Peridotites and their MS;ICP;L minerals 931191 8 Various Iron formation standards INAA;-;S MS;ICP;L .. -- Y AA;-;L 9311919 Various Various Geochemical samples Geochemical exploration Geochemical exploration Geochemical SRMs Geochemical SRMs Geological samples samples s a m p 1 e s Review of different methods of total dissolution Review of the role of AA in geochemical exploration 9311922 93/1923 AE;ICP;L Various Review of the role of ICP-AE in geochemical Review of the role of ICP-MS in geoanalysis Review of the role of XRF in geoanalysis Review of the role of INAA in geoanalysis exploration 9311924 Various Various Various MS;ICP;L XRF;-;S INA A;-$ 9311925 9311926 9311927JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Table 4 (continued) 63 R Technique; atomization; analyte form* NAA;-;S Element Various Various Matrix Geological samples Sample treatment/commentst Reference 9311928 9311930 Review of the current state of radiochemical NAA Interaction of HCl with dissolved silicate material and of INAA in geoanalysis shown to interfere with alkali element determinations. HN03 recommended as an alternative acid medium Samples prepared by acid digestion with no further preconcentration or separation; both major and trace elements determined Review with 21 refs. Samples fused in graphite crucibles followed by polishing to remove imperfections thus removing need for expensive Pt ware Platinum group elements and Au converted to sodium salts by dry chlorination followed by dissolution in dilute HCl.Recoveries of > 90% obtained allowed 8 min of data aquisition from 0.5 g of sample solution. 26 elements per sample determined with Be Ge In and Re used as internal standards flash pyrolysis capillary gas chromatograph. As N 0 P S and Se detected simultaneously Summary of the progress made in the production of SRMs over the last 40 years Procedures for the evaluation of the 'best' values in SRMs reviewed Samples fused with Li2B407 with Sr(NO,) added as an internal standard and analysed with LA sample introduction 1 + 1 binder of cellulose + graphite and an internal standard and analysed with LA sample introduction Samples fused with Na202 and dissolved in H20 + H,SO,. Al Cr Fe Mg Mn and Si determined Samples mixed with LiBO + LizB,07 + NaNO and pre-oxidized at 700 "C followed by addition of 15 drops of 120 mg I-' of NH,Br before fusion at 1050°C for 10 min.Cu Pb S and Zn determined HF + H2S04 evaporated to fumes and finally taken up in dilute H,SO,. K Li Na and Rb determined (0.92 1.8 0.34 2.7 pg I-' respectively) Use of complexing sorbents with proprietry name of POLYORGS with selectivity for noble REE and heavy metals discussed. Metals determined directly in the sorbent after elution from the sorbent and following decomposition of the sorbent slurry analysis described discussed. 'H/'H "B/loB 34S/32S and 87Sr/86Sr measured 0.5 g sample digested in HClO + HNO + HF and made up to 100ml. 32 SRMs analysed; 37 elements gave good agreement; discrepancies for were found for three elements (Ga Ge and W) Noble gas isotopes measured Open acid digestion used for most samples but for Recycling nebulization system described which MIP with photodiode array used as a detector for a Powdered solid samples pressed into pellets with a Samples digested in HF + HNO + HC10 or Systematic approach to optimizing conditions for Difficulties in measurements of isotopic ratios Hf Y and Zr an alkali fusion was found necessary for quantitative dissolution age discussed Role of isotopic analysis in determining geological Review with 16 refs.500-fold molar excess of dulcitol or 1000-fold excess of mannitol found to suppress boron volatalization in HF digestion. B. Co. Cr. Cu. Li. ME. Mn. Ni Silcates AA;F;L Various Rock SRMs MS;ICP;L 9311935 Various Rocks Various Geological samples XRF;-;S X R Fi-; S 931200 1 93/2003 Various Rocks MS;ICP;L 9312054 Various Geological samples MS;ICPL 9312058 Various Sediments coal and petrochemical precursors AE;MIP;G 9312068 Various Various Various Geochemical reference Geochemical reference Minerals fly ash and basalt samples samples SRMs 93 J2 107 93/2108 93J2109 Various Fly ash and geological materials MS;ICP;S 93/21 10 Chrome iron ore AE;ICP;L 9312 145 9312 165 Various Various Sulfide minerals XRF;-;S Geological samples AF;ICP;L 9312 167 Various 9312 1 8 1 Various Rocks and ores AA;-;- AE;ICP;- XRF;-;S NAk-;- AA;ETA;SI MS;Ion probe$ 93/2200 931225 1 Various Various Clay coal and sediment Geochemical samples 9312339 Various Geostandards MS;ICP;L 9 3 J23 40 9312346 Various Various Igneous rock samples Geological reference material MS;-;- MS;ICP;L Geological materials MS;-- 9312351 Various 9312391 9312403 Various Various Geological samples High purity quartz SIMS;-;- MS;ICP;L64 R Table 4 (continued) JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 Technique; atomization; analyte form* MS;ICP;L Element Matrix Various Meteorites Sample treatment/commentst Reference Samples digested in HF + HNO f HClO at 140 "C taken to dryness and residues taken up in HNO,. USGS terrestrial rock standards used for calibration; 25 elements measured 9312445 Review with 11 refs. Isotope dilution calibration used. Ba,Ca Cu Fe K Laser ablation sample introduction used; 41 elements Measurements made on board ship. Samples Samples prepared as glass beads; matrix effect Pb and Zn determined determined using matrix-matched standards prepared as 'briquettes' without the use of binder correction performed using de Jongh's theoretical CI correction coefficients Portable instrument used to look for characteristic element patterns which indicate the presence of copper ore 20 SRMs analysed; new data presented for a number of samples.Colorimetry and coulometry also used Energy dispersive instrument used Synchrotron microprobe facility at Brookhaven National Laboratory described Laser ablation sample introduction used; 43Ca used as internal standard with external standards made from part of the samples themselves whose elemental compositon had been determined by solution methods Review with 10 refs. Various Various 93 f2557 9312606 MS;-;- MS;spark source$ Geochemical samples Uranium oxide Sediment SRMs Mn nodules Fe ore MS;ICP;S 931271 3 Various 93f2733 Various Various XRF;-;S XRF;-;S 9312736 Various Copper ore X R Fi-; S 9312749 NIST geochemical standards Various 9312771 Various Various Black Sea pycnocline Geological samples 9312795 9312843 MS;ICPS Various Geological materials 9312901 Various Coal and geological materials Coal sufaces Geological materials MS;ICP;L 9 3/29 3 5 Various Various MS;laser;S MS;ICP;L Al Ca Fe K LI Mg Na S Si and Ti measured Samples prepared as slurries in an acid dispersing agent of Na4P207 + aqua regia and introduced at concentrations of ~2000 pg m1-l.Standards matrix matched with Na,P,O,. Good agreement obtained for SRMs (0.04-0.2 pg g-') Ar Br C1 I K Kr and Xe measured after neutron irradiation and LA.Samples as small as nl analy sed sample mixed with a polvinyl chloride and pressed into a 10mm diameter disc. Glass beads made by fusing 0.5 g of sample + 2.5 g of LiB02 followed by annealing at 425 "C for 20 min taken to dryness and finally taken up in 50% HCl. Al Fe K Mg Na and P determined 0.5 g of sample digested in H2S04 at 230°C for 16 h in a closed PTFE vessel. Solution analysed for Ca Cr Fe K Li Mg Mn Na Si Sr Ti V Zn and Zr; remaining residue ashed and measured for A120 gravimetrically Preliminary assessment of LA sample introduction reported. 55Mn used as multi-element internal standard and 137Ba used as internal standard for REEs Improved drift correction procedure described to fit a polynomial curve to each isotope in the drift correction standard.Microsoft Excel macro supplied to automate the calculations including Os with 39 refs. Laser ablation sample introduction used. 0.1 g of 1 g of sample digested in 10 ml HF + 3 ml HClO Review of the determination of noble metals Review with 57 refs. of analytical performance 9312936 9313097 Various Various Synthetic fluid incusions Silicate SRM MS;LA;L MS;ICP;S 9313098 9313102 Various Various Phosphate rock Mullite AE;ICP;L AE;ICP;L 9313 174 9313358 Various Silicates MS;ICP;S 9313403 Various Geological samples MS;ICP;L 9313450 Various Rocks M S;ICP;- 9313497 Various Geological and geochemical samples Various Minerals Various Coastal sediments MS;ICP;- 9313515 SIMS;-;S INAA;-$ AA;ETA;L X R F;-;S AA;-;- AE;-;- A&-;- MS;ICP;L MS;ICP;L XRF;-;S Study of fingerprint charateristics of minerals Sources of polluting elements traced from their Cr Fe Mn Si Ti V and Zr determined distribution patterns 9313516 93/36 15 Various Heavy mineral deposits 9313 63 2 Various Estuarine and coastal Various Geological samples Various Geological samples sediment Al Ag As Au Cd Cr Cu Fe Mn Pb Sn and Zn Quality control procedures described Low dilution fusion technique with a flux to sample ratio of 2:l described.Three different methods of calculating ct coefficients evaluated determined 9313633 9313655 9313798JOURNAL O F ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 65 R Table 4 (continued) Element Matrix Technique; atomization; analyte form* Sample treatment/commentst Reference Various Geological samples XRF-;S Specially treated LiF 200 analysing crystal shown to 93/3804 have improved LODs for heavy elements.Samples prepared as pressed powder pellets proportional scintillation counter described radiation X-ray microprobe applications with 61 refs. Various Biotite pyrite/chalcopyrite XRF;-;S Simple inexpensive high performance gas 93/38 13 Various Rocks and minerals XRF;-;S Review of nuclear microprobe and syncrotron 93/3909 * Hy indicates hydride and S L G and S1 signify solid liquid gaseous or slurry sample introduction respectively. Other abbreviations are t Values in parentheses are dtection limits. listed elsewhere. Subsequent determination of Ba Ca ratios on the purified shells used ID-ICP-MS to determine Ba and AAS to determine Ca both with precisions of f3%.The amount of talc in complex ores was measured by roasting the sample at 650°C followed by boiling with 50% HCl (93/644). Talc remained unaffected by this treatment and decomposition of the insol- uble residue using HF+HClO enabled the Mg content to be determined by AAS to provide an estimate of the amount of talc. Chinese workers were able to extract Au from six mineral phases in geological materials by using four different leaching solutions 0.5% I + 1 YO NH,I; 1 O h HClO,; Br + CH,OH; and 50% HCl + SnCl (93/731). Determination by ETAAS pro- duced an LOD of 0.1 ng g-' of Au. Two Japanese workers determined nine trace elements in high-purity quartz using ICP-MS after sample decomposition with HF (93/2403). The suppression of the volatilization of B by dulcitol mannitol and solbitol was studied dulcitol being the most effective.When Be and V were used as internal standards LODs of 0.005-0.01 pg 8-l were obtained. A comparison ofdiyfferent digestion procedures for the determi- nation of Hg in sediments showed that each gave similar results (93/1273). The methods studied used decomposition with ( i ) HN03 + KMnO,; (ii) HNO + H,SO + KMnO,; and (iii) HNO +NaCl with determination by AAS. 4.2.3. Decomposition using fusion Analysis of iron ore samples used decomposition with HNO + HCl followed by fusion of the insoluble residue with Na2B,0 + Na,CO,. After combining the two solutions Fe was extracted with 4-methylpentan-2-one and the aqueous phase used for the determination of Co Cr Cu Mn Ni and Zn by AAS with As Cd Pb and V being determined by ETAAS (93/C961). Decomposition of chrome iron ore was effected by mixing 0.2 g of sample with 3 g of Na,02 in a silver crucible and heating at 650 "C for 10 min prior to analysis by Several automated fusion systems have been reported during the past year.It is obviously very important to consider safety factors when analysing mixed oxides used in nuclear fuels. An automated system enabled glass discs to be prepared by fusion with Na,B,O at 1100°C in a platinum crucible (93/1818). Plutonium and U concentrations were determined by XRF with RSD values of 0.2-0.5%. Another automatic instrument prepared samples for analysis by LA-ICP-MS by fusion with Sr(NO,),+Li,B,O to provide a glass bead Sr being used as an internal standard (93/2109).Detection limits ranged from 0.02 to 3 pg g-'. This approach has the advantage that the bead can also be analysed by XRF. Brenner (93/C1426) described an automated digestion ICP-AES analytical scheme for geochemical prospecting using an Na202 fusion procedure. He reported that an Fl system enabled determinations of Au REEs and ultra-trace elements to be made on the same solution using ICP-MS (93/C1426). Fusion with NaF was used for the determination of Be in ICP-AES (93/2145). beryl (93/3155). Addition of H2S04 to the fusion product followed by heating removed fluoride. After dissolution of the residue in HC1 Be was determined by ICP-AES using the 234.861 nm line. 4.2.4. Decomposition by other methods Dry chlorination is an effective technique for decomposing rock pulps in order to extract the PGEs and Au as soluble chlorides (93/C913 93/C1316 93/2054).A mixture of rock pulp and NaCI contained in a Vycor chlorination tube was heated in a stream of Cl at 570°C for 3.5 h. The soluble salts were extracted with dilute HC1 and the resultant solution analysed using ICP-MS. Seven RMs were analysed for Br C1 and I after decomposition by pyrohydrolysis (93/1917). Powdered samples were irradiated mixed with V205 NaBr NaCl and NaI placed in a nickel crucible and heated at 1200 "C. The volatile halogen gases were absorbed in NaOH and determined using instrumental NAA. For a 50 mg sample the LODs of the method were 0.2 2.9 and 0.1 mg kg-I for Br C1 and I respectively. 4.2.5. Separation and preconcentration The number of reports on separation and preconcentration of determinands before analysis has dropped sharply compared with the previous year.This may be due to the considerable increase in the use of ICP-MS techniques which being sensitive and highly selective have made the need for chemical pre- treatment of samples much less important. 4.2.5.1. Solvent extraction. Three Japanese workers have proposed a scheme for the diferential determination of Hg compounds in sediments based on successive solvent extractions (93/549). Organically bound Hg was extracted with CHC1,. The residue was treated with 0.05 mol 1-l H2S04 to extract HgO and HgS was extracted with 1 mol 1-l HCI containing 3% NaCl in the presence of CuC1. Determination of Hg used CVAAS and recoveries on spiked samples were close to 99%.The determination of low levels of trace elements is facilitated by their separation and preconcentration using solvent extrac- tion. Interference from iron in the determination of Ga in iron meteorites was overcome by extracting Ga as a chloro-complex into IBMK from 5 moll-' HCI in the presence of KI (93/2133). The co-extraction of iron was <2% and determination of Ga by ETAAS gave an LOD of 50 ng 8-l with an RSD of 1.1%. Separation of Mo Nb Ta and W from rock matrix elements was accomplished using N-benzoyl-N-phenylhydroxylamine dissolved in CHCl after sample decomposition with HF (93/3375). All major constituents except Ti remained in the aqueous phase. Twenty RMs were analysed by this technique using ICP-MS.Improvements for the extraction of Se have been reported (93/C933). By using a bromide medium and diluting hexene with toluene the extraction of organoselenium compounds was achieved in less than 30 min. Only Au Pd66 R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 and Pt were co-extracted. Measurement by AAS enabled 0.01-10 ppm of Se to be determined in geological samples. Thiourea has been used for the extraction of gold from roasted ore samples (93/2023). Subsequent adsorption of the extracted Au onto activated charcoal for determination by EDXRF gave an LOD of 0.04 pg 8-l with 98-100% recovery. 4.2.5.2. Ion exchange. Most reported applications of ion- exchange techniques used anion-exchange separation to precon- centrate and separate the determinants of interest.Uranium concentrates after treatment with H2S04 + H20z were passed through an anion-exchange resin enabling Na and K to be separated from the matrix and determined using AAS (93/1274). Beneteau and Richardson (93/1934) used anion exchange to separate Re from unwanted and interfering elements for the determination of Re 0 s isotopic ratios in geological samples prior to analysis by ICP-MS. An effective method using an amine containing resin for the separation of Te was reported (93/651). Tellurium was adsorbed onto the resin from 3 mol 1-1 HC1 and then re-eluted with water. Trace amounts in geological samples down to the ppb level were determined by AFS. 4.2.5.3. Coprecipitation. A novel on-line continuous precipit- ation-dissolution system has been described for the determi- nation of Ni in rocks by AAS (93/C122).After sample decomposition Ni was precipitated by 1-nitroso-2-naphthol and re-dissolved in ethanol. This solution was introduced directly to the AA nebulizer. Flow rates pH and reagent concentrations were all optimized. The addition of H20 and 1,2-dihydroxybenzene-3,5-disulfonic acid disodium salt (tiron) masked interferences from Co and Fe respectively. The pro- cedure was tested on several RMs giving good agreement with published values. After fusion of samples with Na202 coprecipitation with oxalate was used to separate the REEs and Y from matrix elements in rare earth ores (93/3142). Dissolution of the precipitate in HNO gave a solution amenable to analysis by ICP-AES. 4.2.5.4. Vapour generation.Conventional methods of vapour generation usually employ a batch system. The introduction of a flow injection-hydride generation technique has resulted in many improvements and advantages to this method of sample treatment. Detailed investigations into this system in conjunc- tion with analysis by AFS established operating parameters for the determinations of As Bi Hg Sb Se and Te (93/1013). Detection limits with the FI system were better than those with the batch system by factors of 2.5-10. Sample volumes were reduced to 500 pm and linear ranges were 2-3 orders of magnitude of determinant concentrations. The determination of As in sediments by FI-HG-AAS resulted in a reduction of interferences compared with those observed with the batch system (93/C106).Argon flow rate reaction coil volume and atomization temperature were optimized. After reduction to As"' 100% recovery and an RSD of 3% were obtained for RMs. A palladium-coated graphite furnace at low temperature can be used to trap evolved gases produced by the FI-HG tech- nique. This method has been used to determine trace and ultra-trace amounts of Ge by ETAAS (93/3227). The evolved hydride and H2 were separated in a gas-liquid separator and transferred to a palladium-coated graphite furnace kept at 400°C which retained the determinant. The LOD obtained was 0.03 pg 1-1 in solution with an RSD of 2.5% and the method was successfully tested on geological RMs. In a similar system the evolved gases were adsorbed onto a palladium- coated graphite furnace heated to 600°C (93/C153).The determination of Sn in sediments used a similar technique resulting in an LOD of 7 ng 1-1 for a 10 ml sample (93/3964). Studies on the recoveries of As Bi Ge Sb Se Sn and Te showed the process to be at least 80% efficient. 4.3. Instrumental Analysis 4.3.1. Atomic absorption spectrometry The number of papers reporting developments in AAS has decreased sharply over the past year probably due to consider- able interest in ICP-AES and ICP-MS techniques. A note- worthy exception was a detailed investigation into interferences caused by anionic matrices on the determination of alkali elements by AAS (93/1930). It was concluded that HC1 at moderate levels can be responsible for matrix effects. The use of HNO was recommended for the determination of K and Na in silicate samples.Electrothermal atomization methods are still widely used because of their sensitivity. A conference presentation by Hoenig (93/C880) discussed the application of ETAAS to environmental analysis and the advantage and role of chemical modifiers and compared classical and 'fast' analytical pro- grammes. He described an automated system for the determi- nation of eight trace elements in slurry samples. The determination of Ag in rocks and minerals using a rapid ultrasonic suspended solid sampling ETA AS technique has been reported (93/653). The LOD was 0.1 ngml-' with an RSD of 3.06% for an RM containing 3.2 pg 8-l of Ag. The Au content of 26 Japanese RMs has been determined by ETAAS after extraction with IBMK (93/1914) and Sen Gupta (93/3412) determined Sc Y and eight REEs in three RMs by simultaneous multi-element ETAAS with Zeeman background correction.The determination of mercury in environmental samples is important because of the toxicity of this element. Welz et al. (93/412) used a Pd(N0,)2-Mg(N0,) modifier in ETAAS to introduce a 'mild' pyrolysis step at 400°C before complete atomization at 1000°C. A characteristic mass of 0.1 ng of Hg was obtained. Interferences from NaCl were eliminated by using 95% Ar-5% H as the purge gas. Three Russian workers used ETAAS to investigate the form of Hg in rocks (93/3283). The temperatures of maximum and final release of Hg were the most reliable and useful parameters. Analysis of sediments by ETAAS has been the subject of several investigations.The determination of Mo and V in marine sediments provided information about redox potentials and the mobility of these elements (93/C1617). A combination of LC and ETAAS enabled the concentration of Sn in sediment samples to be determined (93/1099). River sediments were analysed for T1 using consecutive leaching techniques (93/637). Direct powder atomization using an Ni(N0,)2 solution as a chemical modifier was used to determine Cu and Mn concen- trations in natural quartz (93/709). Analysis using ETAAS gave detection limits of 3.6 pg for Cu and 2.6 pg for Mn. 4.3.2. Atomic emission spectrometry Some fundamental studies on the analysis of geological samples have been reported. Ramsey and Coles (93/463) discussed various methods of calibration in ICP-AES to derive a strategy for maximizing the accuracy of geochemical analyses.The use of both simple internal standards and the parameter-related internal standard method (PRISM) was examined with the latter being proposed as a method for reducing self-matrix effects and obviating the need to matrix match standards and samples. A form of background correction for ICP-AES the Liberty dynamic background correction system interpolates the true background under a peak according to an algorithm produced from data points on either side of an analytical peak (93/C952). This method was used to determine Pb at 220.350 nm in the presence of potentially interfering aluminium. The analysis of coals for trace elements is important for pollution studies. Forms of S in coal were determined by ICP- AES (93/2712). Pyritic-S was measured indirectly via pyriticJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 67 R Fe; sulfate-S was measured from an HCl extract. This method was more rapid than conventional BaSO precipitation tech- niques and used only a tenth of the sample mass. Coal ash samples were analysed for B after digestion in a microwave oven using HF and HCl-tHNO (93/1929). Boron was deter- mined at 246.678nm using ICP-AES with an LOD of 2.5 The analysis of geological materials by direct sample insertion in ICP-AES has been improved by a combination of changes in probe design and development of different methodologies (93/C212). Two RMs were studied to monitor the results obtained. A further study by Blain and Salin (93/534) showed that the use of an internal standard compensated for changes in analytical conditions which is not particularly surprising.The method of standard additions facilitated the determination of Cd Cu Hg Mn Pb and Zn in sediments. A detailed review citing 103 refs. examined all aspects of ICP-AES in connection with exploration geochemistry (93/1924). 4.3.3. Inductively coupled plasma mass spectrometry A great deal of investigative work has been applied to the determination of trace elements by inductively coupled plasma mass spectrometry. Major minor and trace elements were determined in six RMs following conventional acid digestion using Rh as an internal standard (93/1935). Japanese workers determined 37 trace and ultra-trace elements in 32 RMs (93/2339) and Tang et al.(93/2346) determined more than 40 trace elements in 11 Chinese RMs. Results ranged from sub- ppm to several hundred ppm illustrating the versatility of ICP-MS. Balaram (93/2430) determined REEs in 0.1 7'0 rock solutions without any separation or preconcentration steps and peridotites were analysed for 14 REEs with accuracy and precision comparable to that of SSMS (93/1918). Bailey et al. (93/3223) were able to determine Th and U in basalts using conventional acid digestion without preconcentration the opti- mum storage conditions for solutions being 5% HNO in high-density polyethylene containers. Concentrations of Th and U from ppm to ppb were measured. They also successfully determined levels of U in aqueous solutions down to 0.5 fg ml-I by using complexation with EDTA prior to analysis by ICP-MS ETV being the method of sample introduction (93/3223).The determination of PGEs was the subject of two conference presentations (93/C913 93/C1315). A detailed study into factors afecting accuracy and precision concluded that instrumental drift and variation of instrument response as a function of mass were the primary sources of error in ICP-MS analyses (93/3450). An improved non-linear drift correction programme was described. Beneteau (93/3655) emphasized the need to provide good quality control samples. When the amount of sample available for analysis is limited e.g. mineral separates a recycling nebulization system coupled with a disposable spray chamber can be used (93/2058). Four internal standards (Bi Ge In and Re) were used to correct for matrix effects and instrumental drift when 26 trace elements were determined in four RMs.The same system was used to determine 14 REEs in RM PCC-1 after cation-exchange pre- concentration and LODs between 0.01 and 1.0 ng 8-l were obtained (93/2058). The unique ability of ICP-MS to provide isotopic data on geological samples is one of its strongest points. Reliable trace element data in sediments were obtained using In and/or Bi as internal standards. A precision of 0.5% was obtained for 206Pb 207Pb ratios (93/C1320). Isotopic and elemental analyses of uraninite concentrates were easily and rapidly obtained using ICP-MS 'O'Pb 207Pb 232Th and 238U being determined for age dating (93/1920). In a further application Beneteau and Richardson (93/1934) determined Re 0 s isotopic ratios in rocks.They obtained precisions of 0.34% for IE70s 1880s and 1.0% for lssRe* .187Re with the procedure taking 5 d to complete. C1g g-l. The combination of sample introduction by laser ablation followed by determination using ICP-MS has been extensively studied as this is a way of avoiding high solid content in solutions and solvent-related interference problems. Perkins et al. (93/3102) described the determination of trace and ultra- trace elements in silicates with samples prepared both as pressed powders and as fused glass discs In being used as an internal standard in both cases. Analyses were produced at a rate of 10 samples h-' and the method tested using three Japanese RMs. Detection limits obtained were better than those achieved with XRF and compared favourably with those from instrumental NAA.For quantitative multi-element deter- mination in silicates Williams and Jarvis (93/3403) used "Mn and 137Ba as internal standards for multi-element determi- nations and determinations of Hf Ta W and REEs respect- ively. The method was tested using pressed powder pellets of seven RMs LODs being less than a few hundred ng g-' with accuracy for major elements being 5 5 % RSD (93/3403). Durrant (93/2713) described the determination of 41 elements in two reference sediments using LA-ICP-MS with virtually no sample preparation. 4.3.4. Other mass spectrometric methods Thermal ionization mass spectrometry has been used to deter- mine the precise boron isotopic composition of rocks using the boron-mannitol complex (93/2248).The Cs2B02+- graphite method enabled llB loB ratios to be measured with an RSD of 0.2%. Xiao et al. (93/3099) used a similar method to determine B isotopic compositions of brines and sediments. Analysis of H3B03 by this technique gave an RSD of 0.026% for 'lB I0B ratios. Kloetzli (93/2250) took the alternative approach and used the negative B0,- ion for analysis. He obtained a 100- to 1000-fold increase in sensitivity over the Cs2B0,+ method using La(NO,) as an activator in negative TIMS. A precision of 0.2% was obtained on a sample contain- ing as little as 0.1 ng of B. Hafnium isotope ratios have been determined by TIMS following extraction of Hf to avoid contamination from Ti and Zr (93/C253). The 87Sr 86Sr ratios have been determined in 13 RMs after a chromatographic separation of Sr (93/2900) and 230Th/232Th atom ratios as low as 5 x measured in young volcanic rocks from Antarctica by single sector TIMS (93/3496).A sample containing 300 ng of Th was sufficient for analysis and only a simple chemical separation step was required. Kelly and Murphy (93/1913) described a new procedure for accurate and precise determi- nation of S in geological materials using ID-TIMS. The method was tested on seven RMs and yielded an accuracy of 0.3% RSD. Several studies on REE determinations in silicates using secondary ion muss spectrometry have been described. A com- parison between results obtained using SIMS NAA and ICP- AES techniques for the analysis of gabbro GOG-1 showed that all three methods gave consistent results (93/1915).An investigation into the effect of matrix structure on secondary ion signals using conventional energy filtering (CEF) tech- niques found that the efficiency of REE ionization was not affected by sample structure and that fused glass could be used for analysis (93/2469). A further study on the effect of using either CEF or specimen isolation modes of operation con- cluded that each technique had advantages and disadvantages but both were equally quantitative (93/3094). Isotope dilution techniques are often used in conjunction with mass spectrometric methods. The determination of 0 s in molybdenite important for Re-0s age dating has been achieved by ID-MS (93/1033). Eight trace elements in U308 have been determined using ID-SSMS (93/2606).A group of French workers successfully determined Th and U in silicate rocks by ID-ICP-MS using a 230Th-235U tracer solution (93/2130). Acid decomposition of 0.1 g of sample in a closed Teflon vessel was followed by dissolution of the residue in 2% HNO,. This technique which avoids the need for matrix-68 R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 matched standards and is relatively insensitive to chemical effects and intensity drift was tested on RMs. Laser microprobe noble gas mass spectrometry is a method used for determining very small amounts of trace elements in fluid inclusions. Samples have been analysed for Ar Br Cl I K Kr and Xe abundances and isotopic compositions following neutron irradiation (93/3098).The technique was quantified using synthetic fluid inclusions. 4.3.5. X-ray methods Several investigations on the analysis of geological samples by XRF have concentrated on mathematical treatment of data by various methods to improve data quality. An iterative algor- ithm has been described for use with Compton scatter correc- tions for determinations of trace elements (93/C1886). Problems can occur if anomalously high amounts of trace elements with atomic number greater than 26 are present and this algorithm extends the Compton method to deal with such situations. Fundamental parameter programs using influence coefficients have been used successfully to determine major elements in rocks. The possibility of their use in the determi- nation of trace elements has been investigated (93/C923) and improvements to the fundamental parameter method of X-ray analysis have been reported (93/1793).Eastell and Willis (93/3798) used a low-dilution fusion technique to determine major and minor elements in geological materials. Three different methods were used to calculate CI coefficients (a) multiple regression analysis; (b) the Norrish and Hutton method; and (c) a computer program involving fundamental parameters and the COLA equation. Analytical applications of X-ray fluorescence published include the quantitative determination of BaSO CaSO and SrSO in baryte after fusion with GeO Li,B,O Li2C03 and La203 (93/2018); the determination of Cu Pb S and Zn in sulfide minerals after mixing the sample with LiBO Li2B,07 and NaNO pre-oxidation at 700 "C followed by the addition of NH,Br and fusion at 1050°C (93/2165); and the precise determination of Rb and Sr in silicates essential for geochrono- logical applications by EDXRF (93/C24).Precision was com- parable to that from WDXRF at element concentrations of less than 50 pg g-' but poorer at higher concentrations. Two new techniques for X-ray fluorescence analysis have been described. The first used a treated LiF200 crystal to analyse silicates prepared as pressed pellets (93/3804). Lower LODs were obtained and it was recommended for the routine determination of elements from Ni to Nb. The LOD for Nb was reduced from 0.9 to 0.6ppm. The second method used polarized X-rays as an excitation source (93/C971). This technique reduced the spectral background and increased peak-to-background ratios.Measured LODs in this case were less than 1 pg g-' for many elements. A wide ranging review on X-ray Juorescence in geological analysis dealing with both EDXRF and WDXRF and con- sidering operational and calibration procedures cited 66 refs. (93/1926) while another concerned solely with the determi- nation of trace elements in rocks included 21 refs. (93/2001). 4.3.6. Neutron activation analysis The analysis of international reference materials by instrumental NAA (INAA) has been reported in several publications. Stix and Gorton (93/1916) determined trace elements in ten RMs using a low-flux reactor and Ge detectors. Results were in agreement with recommended values except for Mo and some REEs. Bower et al.(93/2771) analysed 20 RMs using INAA and XRF for ten major elements and 39 trace elements. Both INAA and ICP-MS were used in the analysis of four iron formation samples and an iron RM (93/1919). Joron and Raimbault (93/1931) showed that the effect of 154E~ interference on the determination of Z r by INAA can become quite large when mineral separates are analysed. If the correction is neglected erroneous Zr results could lead to too high Zr Hf ratios. Reviews published on NAA included one on the theoretical aspects of INAA and its application to exploration geochemis- try (93/1927). Another dealing with the status of radiochemical NAA in geoanalysis described several group separation schemes and cited 63 refs. (93/1928). LOCATION OF REFERENCES The full list of references cited in this Update have been published as follows 93lC1-931C997 J.Anal. At. Spectrom. 1993 8( l) 45R-78R. 93/998-93/C1354 J. Anal. At. Spectrom. 1993 8(3) 137R-149R. 93/C1355-93/2093 J. Anal. At. Spectrom. 1993 8(4) 169R-194R. 9312094-9212710 J. Anal. At. Spectrom. 1993,8( 5 ) 239R-262R. 9312711-9313353 J. Anal. At. Spectrom. 1993 8( 7) 313R-336R. 9313354-9314131 J. Anal. At. Spectrom. 1993 8( 8 ) 377R-404R. 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 931410 Analyst 1992 117 1041.931412 J. Anal. At. Spectrom. 1992 7 499. 931442 Anal. Chim. Acta 1992 258 229. 931443 Anal. Chim. Acta 1992 258 237. 931448 Analusis 1991 19 285. 931451 Analusis 1991 19 M51. 931454 Analusis 1992 20 36. 931461 Chem. Geol. 1991,93,291. 931463 Chem. Geol. 1992 95 99. 931473 Zavod. Lab. 1991 57(12) 19. 931476 Zavod. Lah. 1991 57( 12) 30. 93/480 Microchem. J. 1992 45 90. 931481 Microchem. J. 1992 45 97. 93/42 Microchem. J. 1992 45 163. 931484 Water Air Soil Pollut. 1992 62 43. 931485 Water Air Soil Pollut. 1992 62 349. 931491 Guangpuxue Yu Guangpu Fenxi 1991 11(4) 43. 931498 Guangpuxue Yu Guangpu Fenxi 1991 11(5) 41. 931502 Guangpuxue Yu Guangpu Fenxi 1991 11(5) 62. 931504 Guangpuxue Yu Guangpu Fenxi 1991 11(5) 68.931533 Spectrochim. Acta Part B 1992 47 199. 931534 Spectrochim. Acta Part B 1992 47 205. 931546 Anal. Sci. 1991 7 889. 931549 Anal. Sci. 1992 8 35. 931551 Anal. Sci. 1992 8 45. 931557 Anal. Sci. 1992 8 233. 931558 Anal. Sci. 1991 7 1029.JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 69 R 931559 Anal. Sci. 1991 7 1053. 931560 Anal. Sci. 1991 7 1115. 93/561 Anal. Sci. 1991 7 1131. 93/572 Anal. Sci. 1991 7 1381. 931578 Anal. Sci. 1991 7 91. 93/585 Anal. Sci. 1991 7 463. 931590 Anal. Sci. 1991 7 517. 93/619 Fenxi Shiyanshi 1991 10(6) 65. 93/623 Anal. Spectrosc. Libr. 1991 5 (At. Absorpt. Spectrom.) 79. 93/624 Anal. Spectrosc. Libr. 1991 5 (At. Absorpt. Spectrom.) 125. 93/625 Anal. Spectrosc. Libr. 1991 5 (At. Absorpt. Spectrom.) 159. 931634 Anal.Spectrosc. Libr. 1991,5 (At. Absorpt. Spectrom.) 515.931635 Mikrochim. Acta 1991 3 125. 931637 Mikrochim. Acta 1992 106 241. 931644 Yankuang Ceshi 1991,10 193.931645 Yankuang Ceshi 1991 10 207. 93/647 Yankuang Ceshi 1991 10 238. 931648 Yankuang Ceshi 1991 10 247. 93/651 Yankuang Ceshi 1991 10,283.931653 Yankuang Ceshi 1991,10,291.931654 Yankuang Ceshi 1991 10 304. 931655 Lihua Jianyan Huaxue Fence 1991 27 230. 931656 Lihua Jianyan Huaxue Fence 1991 27 249. 931657 Lihua Jianyan Huaxue Fence 1991 27 264. 931658 Lihua Jianyan Huaxue Fence 1991 27 273. 931660 Lihua Jianyan Huaxue Fence 1991 27 303. 93/663 Lihua Jianyan Huaxue Fence 1991 27 314. 931666 Lihua Jianyan Huaxue Fence 1991 27 359. 93/675 Fenxi Huaxue 1991 19 1137. 93/686 Fenxi Huaxue 1991 19 1285.931687 Fenxi Huaxue 1991 19 1288. 931688 Fenxi Huaxue 1991,19 1298. 931691 Fenxi Huaxue 1991,19 ( l l ) inside back cover. 93/700 Fenxi Huaxue 1992 20 196. 93/701 Fenxi Huaxue 1992 20 242. 93/702 Fenxi Huaxue 1992 20 335. 93/709 Bunseki Kagaku 1992 41 89. 931712 Bunseki Kagaku 1992 41 T39. 931718 Fenxi Ceshi Tongbao 1991 10(4) 56. 931719 Fenxi Ceshi Tongbao 1991,10(5) 11.931727 Environ. Technol. 1991 12,769.93/728 Environ. Technol. 1991,12,935.931729 Environ. Technol. 1992 13 95. 931730 Yejin Fenxi 1991 11(2) 25. 931731 Yejin Fenxi 1991 11(3) 1. 931732 Yejin Fenxi 1991 11(3) 27. 93/757 Fresenius’ J. Anal. Chem. 1992 342 107. 931761 Fresenius’ J. Anal. Chem. 1992 342 175. 931762 Fresenius’ J. Anal. Chem. 1992 342 179. 931769 Fresenius’ J. Anal. Chem. 1992 342 391.93/776 Fresenius’ J. Anal. Chem. 1992 342 822. 931813 J. Autom. Chem. 1991 13 281. 931839 Acta Chim. Hung. 1991 128 483. 931840 Acta Chim. Hung. 1991 128 507. 931845 Ann. Chim. (Rome) 1991 81 343.931847 Chem. Listy 1991,85 1235.93/850 Environ. Pollut. 1992 76 251. 931851 Enuiron. Sci. Technol. 1992 26 834. 931857 Int. J. Environ. Anal. Chem. 1991,45 159.931866 Quim. Anal. (Barcelona) 1991 10 59. 931998 J. Anal. At. Spectrom 1992 7 25N. 93/1000 J. Anal. At. Spectrom. 1992 7 587. 93/1001 J. Anal. At. Spectrom. 1992 7 595. 9311003 J. Anal. At. Spectrom. 1992 7 605. 93/1004 J. Anal. At. Spectrom. 1992 7 611. 9311007 J. Anal. At. Spectrom. 1992 7 629. 9311008 J. Anal. At. Spectrom. 1992 7 635. 93/1010 J. Anal. At. Spectrom. 1992 7 647. 9311013 J. Anal. At. Spectrom.1992 7 667. 93/1017 J. Anal. At. Spectrom. 1992 7 695. 9311023 J. Anal. At. Spectrom. 1992 7 727. 9311028 J . Anal. At. Spectrom. 1992 7 761. 9311031 J. Anal. At. Spectrom. 1992,7,775.93/1033 Analyst 1992,117,1151.93/1035 Analyst 1992 117 1161. 9311040 Analyst 1992 117 1477. 9311041 Analyst 1992 117 1478. 93/104S Anal. Proc. 1992 29 280. 9311050 Anal. Proc. 1992 29 282. 9311051 Anal. Proc. 1992 29 282. 9311054 Anal. Proc. 1992 29 287. 9311055 Anal. Proc. 1992,29,288.9311057 Anal. Proc. 1992,29,293.9311068 Can. J. Appl. Spectrosc. 1992 37 94. 9311077 At. Spectrosc. 1991,12 233. 9311094 Agrochemia (Bratislava) 1991,31 282. 9311095 Ankara Univ. Eczacilik Fak. Derg. 1990 20 25. 9311098 Appl. Occup. Environ. Hyg. 1991 6 1027. 9311099 Appl. Organomet. Chem. 1992 6 39.9311100 Appl. Plasma Source Mass Spectrom. [Sel. Pap. Int. Con5 2nd] 1990 110. 9311103 ASTM Spec. Tech. Publ. 1991 1115 (Plants Toxic. Assess. 2nd vol.) 172. 9311110 Bioresour. Technol. 1992 40 73. 93/1121 Chem. Erde 1991 51 297. 9311125 Chromatographia 1991 32 583. 9311127 Common. Eur. Communities [Rep.] EUR 1992 EUR 14062 64. 9311128 Commun. Soil Sci. Plant Anal. 1992 23 441. 9311135 Environ. Geochern. Health 1991 13(2) 50. 93/1137 Enuiron. Pollut. 1992 76 157. 9311141 Forschungszent. Julich Ber. 1991 Juel 2512 186. 93/1144 Ganko 1991 86 432. 93/1151 Haiyang Xuebao (Zhongwenban) 1991 13 581. 9311158 HortScience 1991 26 1496. 9311169 Izv. Khim. 1991 24 67. 9311178 Kidorui 1991 18 126. 93/1181 Lab. h i m . Sci. 1991 41 233. 9311191 Mar. Environ. Res. 1991 32 19.9311198 Miner. Slovaca 1990,22,367.931 1201 Nippon Dojo Hiryogaku Zasshi 1991 62 628. 93/1202 Nippon Dojo Hiryogaku Zasshi 1992 63 53. 9311204 Nippon Kagaku Kaishi 1992 1 118. 93/1205 Nippon Kagaku Kaishi 1992 3 307. 9311209 Orient. J. Chem. 1991,7 148.9311212 Pharmacol. Toxicol. (Copenhagen) 1992 70,308. 93/1214 Phys. World 1992,5(2) 23.9311215 Pr. Cent. Inst. Ochr. Pr. 1989 39 161. 9311216 Pr. Cent. Inst. Ochr. Pr. 1990 40 127. 9311217 Pr. Cent. Inst. Ochr. Pr. 1990 40 187. 9311218 Pr. Cent. Inst. Ochr. Pr. 1990 40 283. 9311225 Redai Haiyang 1991 10(2) 93. 93/1226 Redai Haiyang 1991 10(3) 71. 93/1227 Redai Haiyang 1991 10(3) 101. 93/1230 Rev. Roum. Chim. 1991 36 71. 9311231 Rev. Roum. Chim. 1991 36 901. 93/1239 Shaghai Huanjing Kexue 1991 10(7) 30. 9311240 Shanghai Huanjing Kexue 1991 10(8) 34.9311246 Sichuan Daxue Xuebao Ziran Kexueban 1991,28,186.9311261 Trends Anal. Chem. 1992 11 17. 9311262 Turang Tongbao 1991,22,281.9311263 Turang Tongbao 1991,22,283.93/1272 Yongu Pogoso Hanguk Tonglyok Chawon Yonguso 1991 KR-90-3D-1 79. 9311273 Yosui to Haisui 1991 33 926. 93/1274 Youkuangye 1991,10,46.93/1284 Zhongnan Kuangye Xueyuan Xuebao 1991 22 582. 9311644 Spectrochim. Acta Part B 1992,47 1155. 93/1652 Fresenius’ J. Anal. Chem. 1992 342 444. 9311654 Bull. Rech. Agron. Gembloux 1992 27 133. 9311657 Nucl. Instrum. Methods Phys. Res. Sect. B 1992 69 479. 9311665 Huanjing Huaxue 1992 11(3) 55. 9311666 Process Metall. 1992 7A. 9311671 Spectroscopy (Eugene Oreg.) 1992 7(5) 40 42. 93/1672 Zh. Anal. Khim. 1992 47 383. 9311682 X-Ray Spectrom.1992 21 143. 9311702 Acta Cient. Venez. 1991 42 247. 93/1707 Fenxi Shiyanshi 1992 11 54. 93/1708 Nucl. Sci. Tech. 1992 3(1) 19. 9311709 J. Radioanal. Nucl. Chem. 1992 158 401. 9311716 Environ. Sci. Res. 1991 42(Chem. Prot. Environ.) 155. 9311717 J. Environ. Radioact. 1992 16 109. 9311741 Commun. Soil Sci. Plant Anal. 1992 23 569. 93/1768 J. Radioanal. Nucl. Chem. 1992 64 357. 9311770 Anal. Sci. 1991 7(Suppl. Proc. Int. Congr. Anal. Sci.) 1991 1175. 9311774 Wutan Yu Huatan 1991 15 284. 93/1776 Bull. Environ. Contam Toxicol. 1992 48,803. 9311793 X-Ray Spectrom. 1992,21,69.9311801 Fenxi Huaxue 1992 20 176. 93/1804 Cesi Farm. 1992 40 226. 9311816 Zavod. Lab. 1992 58 25. 9311818 Comm. Eur. Communities [Rep.] EUR 1991 EUR 13686 Annu. Symp. Safeguards Nucl.Muter. Manag. 13th 1991 245. 93/1829 Int. J. Environ. Anal. Chem. 1991 45 275. 9311843 Proc. Annu. Meet. Air Waste Manage. ASSOC. 1991 84 Paper 91189.2. 9311845 Bull. Chem. SOC. Ethiop. 1991,5(2) 49.9311853 USSR SU 1,672,325 (Cl. GO1 N23/223) 23 Aug 1991 Appl. 4,476,465 30 May 1988. Otkrytiya Izobret. 1991,31 178. 9311857 Fenxi Shiyanshi 1991 10(5) 11. 93/1858 Analusis 1992 20(3) M50. 93/1862 Commun. Soil. Sci. Plant Anal. 1991,22,2063.9311863 USSR SU 1,679,319 (Cl. GOlN23/223) 23 Sept. 1991 Appl. 4,736,827 12 Jul 1989. Otkrytiya Izobret. 1991 35 167. 93/1866 Steel India 1991 14 41. 93/1870 GIT Fachz. Lab. 1991,35 1327. 93/1890 Proc. Annu. Meet. Air Waste Manage. ASSOC. 1991 84th Paper 90.5. 9311913 Geostand. Newsl. 1992 16 3. 9311914 Geostand. Newsl. 1992 16,9.9311915 Geostand. Newsl. 1992 16 13. 9311916 Geostand. Newsl. 1992 16 21. 9311917 Geostand. Newsl. 1992 16 41. 9311918 Geostand. Newsl. 1992 16 311. 9311919 Geostand. Newsl. 1992 16 325. 93/1920 J. Geochem. Explor. 1992,44,111.9311921 J. Geochem. Explor. 1992 42 345. 93/1922 J. Geochem. Explor. 1992 44 65. 9311923 J. Geochem. Explor. 1992 44 107. 93/1924 J. Geochem. Explor. 1992,44,139.9311925 J. Geochem. Explor. 1992 44 201. 9311926 J . Geochem. Explor. 1992 44 251. 9311927 J. Geochem. Explor. 1992,44,297.9311928 J. Geochem. Explor. 1992 44 321. 93/1929 Chem. Geol. 1992 98 317.70 R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 9311930 Chem. Geol. 1992,98,323.9311931 Chem. Geol. 1992 98 327. 9311932 At. Spectrosc. 1992 13 127. 9311934 At.Spectrosc. 1992 13 118. 9311935 At. Spectrosc. 1992 13 113. 9311987 Adv. X-Ray Anal. 1991,34 41. 93/1994 Zavod. Lab. 1991 57(11) 24. 9312001 Adv. X-Ray Anal. 1991 34 263. 9312003 Adv. X-Ray Anal. 1991 34 213. 9312011 J. Environ. Sci. Health Part A 1992 A27 419. 9312018 Vestn. Slov. Kem. Drus. 1991 38 493. 9312023 Fresenius’ J. Anal. Chem. 1992 343,292. 9312051 J. Anal. At. Spectrom. 1992,7,865.9312054 J. Anal. At. Spectrom. 1992 7 883. 9312055 J. Anal. At. Spectrom. 1992 7 889. 9312058 J. Anal. At. Spectrom. 1992 7 905. 9312068 J . Anal. At. Spectrom. 1992 7 979. 9312069 J. Anal. At. Spectrom. 1992 7 987. 9312074 J. Anal. At. Spectrom. 1992 7 1019. 9312087 J. Anal. At. Spectrom. 1992 7,2087.9312091 J. Anal. At. Spectrom. 1992,7 1139.9312107 Spectrochim. Acta Part B 1991,46,1623.9312108 Spectrochim.Acta Part B 1991 46 1639. 9312109 Spectrochim. Acta Part B 1991,46 1803.93/2110 Spectrochim. Acta Part B 1991,46 1819. 9312121 Appl. Spectrosc. 1991 45 1433. 9312122 Appl. Spectrosc. 1991 45 1561. 9312123 Appl. Spectrosc. 1991 45 1568. 9312130 Anal. Chim. Acta 1992,256 153. 9312133 Anal. Chim. Acta 1992 259 289. 9312134 Anal. Chim. Acta 1992 259 295. 9312140 Analusis 1992 20(3) M24. 9312145 Lihua Jianyan Huaxue Fence 1992 28 80. 9312150 Lihua Jianyan Huaxue Fence 1992 28 113. 9312155 Anal. Chem. 1992 64 737. 9312163 Anal. Chem. 1992 64 2253. 9312165 Fenxi Shiyanshi 1992 11(2) 52. 9312167 Fenxi Shiyanshi 1992 11(2) 75. 9312169 Fenxi Shiyanshi 1992 11(3) 8. 93/2178 Fresenius’ J. Anal. Chem. 1991 341 559. 9312179 Fresenius’ J. Anal.Chem. 1991 341 568. 9312180 Fresenius’ J. Anal. Chem. 1991,341 570.9312181 Fresenius’ J. Anal. Chem. 1991 341 586. 9312191 Eisei Kagaku 1991,37 17. 9312195 Bunseki Kagaku 1992,41 T77.9312197 Bunseki Kagaku 1992,41,317. 9312198 Zh. Anal. Khim. 1991,46,2259.9312200 At. Spectrosc. 1992 13 1. 9312201 At. Spectrosc. 1992 13 7. 9312202 At. Spectrosc. 1992 13 11. 9312206 At. Spectrosc. 1992 13 89. 9312208 At. Spectrosc. 1992 13 99. 9312222 Anal. Sci. 1991 7 997. 9312223 Anal. Sci. 1991 7 1117. 9312224 Anal. Sci. 1991,7 1135.9312229 Anal. Sci. 1991,7,1343.9312247 Chem. Geol. 1991 94 137. 9312248 Chem. Geol. 1992 94 193. 9312250 Chem. Geol. 1992 101 111. 9312251 Chem. Geol. 1992 101 187. 9312252 Earth Planet. Sci. Lett. 1992 111 257. 9312253 Environ. Sci. Technol. 1992,26,1944.9312254 Environ.Technol. 1992 13 207. 9312294 Biol. Cell 1992 74 127. 9312318 Anal. Chim. Acta 1992,259 193.9312319 Anal. Chim. Acta 1992,261,315.9312323 Anal. Div. 1991,25 101.9312324 Anal. Lett. 1992 25 919. 9312339 Ganko 1992 87 107. 9312340 Geochem. J. 1991 25 163. 9312342 Geochim. Cosmochim. Acta 1991 55 3901. 9312346 Geostand. Newsl. 1992,16,61.9312347 Gewaesserschutz Wasser Abwasser 1991 124,101.9312351 LaborPraxis 1992 (Lab. 2000) 185.9312352 Lanthanide Actinide Res. 1991 3 285. 9312361 Muter. Chem. Phys. 1992 31 101. 9312389 Muench. Beitr. Abwasser Fisch. Flussbiol. 1991 45 228. 9312390 Int. J. Environ. Anal. Chem. 1991,45 55.9312391 Kagaku (Tokyo) 1992,62,488.93/2396 J. Radioanal. Nucl. Chem. 1991,151 149.9312397 J. Radioanal. Nucl. Chem. 1992,158,91.93/2403 Tetsu to Hagane 1991,7’7 1959.9312424 J.Chromatogr. 1992,594,275.9312430 J. Indian Chem. SOC. 1991 68 600. 9312445 J. Radioanal. Nucl. Chem. 1992 164 13. 9312469 Scanning 1992 14 160. 9312481 Shitsuryo Bunseki 1991 39 301. 9312535 Nucl. Instrum. Methods Phys. Res. Sect. B 1992,68 309. 9312557 Proc. Aust. Conf. Nucl. Tech. Anal. 1991,7,66.9312565 Pure Appl. Chem. 1992,64 575. 9312604 Yankuang Ceshi 1991 10 171. 9312606 Yuanzineng Kexue Jishu 199 1 25 66. 9312620 Radiocarbon 1992 34 29. 9312621 Radioisotopes 1992 41 185. 9312641 Zavod. Lab. 1991 57(4) 36. 9312648 Nature 1992 356 50. 9312660 Tree Physiol. 1992,10,209.9312677 GITFachz. Lab. 1992 36 115. 9312699 Sci. Total Environ. 1991 107 29. 9312712 Analyst 1992 117 1581. 9312713 Analyst 1992 117 1585.9312717 Analyst 1992,117 1729.9312718 Analyst 1992 117 1735. 9312719 Analyst 1992 117 1743. 9312722 Analyst 1992 117 1929. 9312726 Analyst 1993 118 85. 9312727 Analyst 1993 118 189. 9312730 Anal. Proc. 1992 29 399. 9312732 Anal. Proc. 1992 29 438. 9312733 Fresenius’ J. Anal. Chem. 1992 344 1. 9312734 Bunseki 1992 7 544. 9312736 Anal. Sci. Technol. 1991 4 83. 9312739 Conf. Proc. Ital. Phys. SOC. 1990 25 1013. 9312740 Fett Wiss. Technol. 1992 94 246.9312746 Con5 Proc. Ital. Phys. SOC. 1990,25,875.9312748 Guangpuxue Yu Guangpu Fenxi 1992,12,119.93/2749 Hejishu 1992 15 181. 9312756 An. Asoc. Quim. Argent. 1990 78 265. 9312757 Anal. Chim. Acta 1992 268 177. 9312758 Fresenius’ 3. Anal. Chem. 1992,344,118.9312771 Geostand. Newsl. 1992 16,27.93/2795 NATO ASI Ser. Ser.C 1991,351,89. 9312819 Residues Efluents Process. Environ. Consid. Proc. Int. Symp. 1992 149. 9312822 Pharm. Ind. 1992 54 293. 9312842 Nucl. Geophys. 1991 5 513. 9312843 Springer Ser. Opt. Sci. 1992 67 212. 9312892 Anal. Chem. 1992 64 2945. 9312894 Anal. Chem. 1992 64 2972. 9312896 Anal. Chem. 1992 64 3101. 9312900 Anal. Chim. Acta 1992,269,249. 9312901 Anal. Chim. Acta 1992 269 263. 9312935 Elem. Anal. Coal Its By-Prod. Int. Conf. Proc. 2nd 1991 (Pub. 1992) 97.9312936 Elem. Anal. Coal Its By-Prod. Int. Con5 Proc. 2nd 1991 (Pub. 1992) 149. 9312937 Environ. Sci. Technol. 1993 27 172. 9312938 Eur. Muter. Res. SOC. Monogr. 1992,4,167.9312939 Fenxi Shiyanshi 1992 11(3) 51. 9312940 Fresenius’ J. Anal. Chem. 1992 344 109.9312941 Fresenius’ J. Anal. Chem. 1992,344,279.9312979 Radiochim.Acta 1992 57 15. 9312985 Soil Sci. SOC. Am. J. 1992 56 1151. 9312987 Spectrochim. Acta Part B 1992 47 1379. 9313081 At. Spectrosc. 1992 13 169. 9313090 Talanta 1992 39 1089. 9313094 Chem. Geol. 1993 103 45. 9313095 Chem. Geol. 1993 103 73. 9313096 Chem. Geol. 1993 103 103. 9313097 Chern. Geol. 1993 104 175. 9313098 Geochim. Cosmochim. Acta 1992,56 187. 9313099 Geochim. Cosmochim. Acta 1992,56,1561.9313100 Geochim. Cosmochim. Acta 1992 56 2713. 9313101 Geochim. Cosmochim. Acta 1992 56 4099. 9313102 Geochim. Cosmochim. Acta 1992 57 475. 9313103 Anal. Lett. 1992 25 1545. 9313105 Fresenius’ J. Anal. Chem. 1992 343 600. 9313110 Fresenius’ J. Anal. Chem. 1992 343 754. 9313113 Mikrochim. Acta 1992 108 19. 9313117 Anal. Chim. Acta 1992 262 285. 9313128 Fenxi Ceshi Tongbao 1992 11 64.9313133 Lihua Jianyan Huaxue Fence 1992 28 307. 9313134 Lihua Jianyan Huaxue Fence 1992 28 294. 9313136 Fenxi Huaxue 1992 20 982. 9313137 Fenxi Huaxue 1992 20 985. 9313142 Anal. Chim. Acta 1992 264 333. 9313155 At. Spectrosc. 1992 13 213. 9313157 At. Spectrosc. 1992 13 199. 9313159 At. Spectrosc. 1992 13 193. 9313174 Fenxi Huaxue 1992 20 866. 9313194 At. Spectrosc. 1993 14 8. 9313200 Khim. Tekhnol. Vody 1992 14 418. 9313207 J. Radioanal. Nucl. Chem. 1992 161 101. 9313219 J. Anal. At. Spectrom. 1993 8 499. 9313223 J. Anal. At. Spectrom. 1993 8 551. 9313227 J. Anal. At. Spectrom. 1993 8 577. 9313229 J. Anal. At. Spectrom. 1993 8 591. 9313238 J. Anal. At. Spectrom. 1993 8 649. 9313242 Fresenius’ J. Anal. Chem. 1992 344 54. 9313243 Fresenius’ J. Anal. Chem. 1992 344 234. 9313265 An. Bromatol. 1991 43 51. 9313271 Cesk. Hyg. 1992 37 34. 9313278 Fed. Regist. 1992 57 41830. 9313281 Fenxi Shiyanshi 1992 11 36. 9313283 Geokhimiya 1992 8 1203. 9313292 Indian J. Chem. Sci. 1991 5 77. 9313296 Khim. Tekhnol. Vody 1992 14 109. 9313300 LaborPraxis 1992 16 790. 9313308 J. Chin. Chem. Soc (Taipei) 1992 39 461 9313325 Pollut. Atmos. 1992 134 101. 9313334 Vestn. St. Peterb. Univ. Ser. 4 Fiz. Khim. 1992 1 62. 9313345 Shanghai Huanjing Kexue 1992 11 29. 9313358 Anal. Sci. 1993 9 99. 9313359 Anal. Sci. 1993 9 105. 9313372 Spectrochim. Acta Part B 1993 48 91. 9313373 Spectrochim. Acta Part B 1993 48 111. 9313375 Fresenius’ J. Anal. Chem. 1992 344 326. 9313377 Talanta 1993 40 9. 9313387 J. Anal. At. Spectrom. 1992 7 1183. 9313391 J. Anal. At. Spectrom. 1992 7 1243. 9313403 J. Anal. At. Spectrom. 1993 8 25. 9313404 J. Anal. At. Spectrom. 1993 8 35. 9313408 J. Anal. At. Spectrom. 1993 8 71. 9313409 J. Anal. At. Spectrom. 1993 8 79. 9313412JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 71 R J. Anal. At. Spectrom. 1993 8 93. 9313415 J. Anal. At. Spectrom. 1993 8 115. 93/3417 J. Anal. At. Spectrom. 1993 8 1R. 93/3420 Analusis 1992,20,597.93/3427 Appl. Spectrosc. 1993 47 243. 93/3441 Anal. Chem. 1993 65 1186. 9313442 Anal. Chem. 1993 65 1419. 93/3444 Anal. Chem. 1993 65 1602.9313446 Anal. Proc. 1993 30 159. 9313450 Spectrochim. Acta Part B 1993 48 E487. 93/3464 Anal. Lett. 1993 26 295. 93/3466 Anal. Lett. 1993 26 341. 93/3486 Boll. Chim. Ig. Parte Sci. 1992 43(S3) 177. 93/3489 Can. J. Appl. Spectrosc. 1992,37,176.93/3491 Chem. Anal. (Warsaw) 1992 37 501. 9313492 Chem. Express 1993 8 13. 93/3493 Chem. Geol. 1992,101,173.9313494 Chem. Geol. 1992,102( 1-4) 41. 93/ 3496 Chem. Geol. 1993 103( 1-4) 283. 93/3497 Chem. Listy 1993 87 8. 93/3499 Chem. Speciation Bioavailability 1992 4 97. 9313508 Commun. Soil Sci. Plant Anal. 1992 23 2339. 93/3509 Commun. Soil Sci. Plant Anal. 1992 23 2781. 93/3510 Commun. Soil Sci. Plant Anal. 1993 24 125. 93/3515 Crit. Rev. Anal. Chem. 1992 23 355. 93/3516 Dizhi Xuebao 1991 65(1) 27. 93/3517 Dokl. Akad. Nauk 1992 325 1198. 93/3520 Environ. Pollut. 1993 79 225. 93/3521 Enuiron. Technol. 1992 13 1043. 93/3527 Fenxi Ceshi Tongbao 1992 11(2) 44. 93/3537 Fenxi Shiyanshi 1992 11(4) 50. 93/3542 Food Addit. Contam. 1992 9 365. 93/3550 Gaodeng Xuexiao Huaxue Xuebao 1992,13 1241.93/3551 Geol. Pruzkum 1992 34 270. 93/3593 J. Am. SOC. Mass Spectrom. 1992 3 742. 93/3613 J. Oceanogr. 1992 48 283. 93/3615 J. Radioanal. Nucl. Chem. 1993,167,341.93/3617 J. Radioanal. Nucl. Chem. 1993 175 129. 9313625 Khim. Tekhnol. Vody 1992 14 899. 93/3632 Mar. Min. 1991 10 337. 93/3633 Mar. Pollut. Bull. 1992 24 484. 93/3635 Mass Spectrom. Rev. 1992 11 495. 93/3643 Mikrochim. Acta Suppl. 1992 12 241. 93/3655 Ont. Geol. Surv. Misc. Pap. 1992 160 153. 93/3668 Pochvovedenie 1990 12 122. 93/3682 Redai Haiyang 1992 11 30. 9313683 Report 1991 EPA/600/4-91/010; Order No. PB91-231498 305pp. (Eng). Avail. NTIS. From Gov. Rep. Announce. Index (U. S . ) 1991 91 Abstr. No. 162,094. 93/3708 Sohag Pure Appl. Sci. Bull. 1991 7 16. 9313709 Soil Biol. Biochem. 1992 24 1705. 9313714 Spectroscopy (Eugene Oreg.) 1993 8 38. 9313715 Stud. Cercet. Fiz. 1992 44,407. 9313783 Vom Wasser 1992,79,9.93/3785 Water Sci. Technol. 1992,25,205.93/3791 Yuanzineng Kexue Jishu 1991 25(3) 68. 93/3798 X-ray Spectrom. 1993 22 71. 9313804 X-ray Spectrom. 1993 22 114. 9313807 X-ray Spectrom. 1993 22 28. 9313813 X-ray Spectrom. 1993 22 328. 93/3820 Commun. Soil Sci. Plant Anal. 1992,23,2415.9313821 Fenxi Shiyanshi 1992,11(4) 53. 9313823 Atmos. Environ. Part B 1992 26 421. 9313824 J. Radioanal. Nucl. Chem. 1993 175 33. 9313893 ISTEC J. 1992 5(2) 13. 93/3899 Elem. Anal. Coal Its By-Prod. Int. Con$ Proc. 2nd 1991 (Pub. 1992) 372.93/3909 Fenxi Huaxue 1992 20 850. 93/3922 Anal. Chim. Acta 1992 260 131. 93/3924 Anal. Chim. Acta 1992,261,91.9313944 Fenxi Huaxue 1992 20 162. 93/3947 Fenxi Huaxue 1992 20 429. 93/3950 Fenxi Huaxue 1992,20,535.93/3956 Fresenius’ J. Anal. Chem. 1992 343 614. 93/3964 Spectrochim. Acta Part B 1992 47 701. 93/3970 Talanta 1992 39 671. 93/3978 Analusis 1992 20 M73.93/3985 Bull. SOC. Chim. Belg. 1992,101,473.93/3988 Chem. Environ. Res. 1992 1 3. 9313989 Chemosphere 1992 24 591. 93/3999 Commun. Soil Sci. Plant Anal. 1992 23 559. 93/4000 Commun. Soil Sci. Plant Anal. 1992 23 645. 93/4004 Environ. Int. 1992 18 263. 93/4006 Fenxi Ceshi Tongbao 1992 11 40. 93/4012 Guangpuxue Yu Guangpu Fenxi 1992 12 72. 93/4016 Guangpuxue Yu Guangpu Fenxi 1992 12 119. 9314023 Int. J. Environ. Anal. Chem. 1992 47 227. 93/4024 Int. J. Environ. Anal. Chem. 1992 47 99. 93/4033 J. Chin. Chem. SOC. (Taipei) 1992 39 217. 93/4038 J. Environ. Sci. Health Part A 1992,27,1453.93/4056 Kankyo Kagaku 1992 2,25.93/4057 Khim. Sel’sk Khoz. 1992,4,99.93/4058 Kogyo Yosui 1992 404 9. 9314059 Kogyo Yosui 1992 405 40. 9314060 Kogyo Yosui 1992 405 48. 93/4065 Lihua Jianyan Huaxue Fence 1992,28( l ) 54.93/4066 Lihua Jianyan Huaxue Fence 1992 28(1) 57. 93/4071 Microchem. J. 1992 46 121. 93/4075 Nippon Dojo Hiryogaku Zasshi 1992 63(2) 210. 93/4076 Nippon Dojo Hiryogaku Zasshi 1992,63,345.93/ 4077 Nippon Kagaku Kaishi 1992 6 667. 9314079 Nippon Kaisui Gakkaishi 1992 46 22. 93/4088 Jpn. Kokai Tokkyo Koho JP 04,141,240 [92,141,240] (Cl. BOlL1/04) 14 May 1992 Appl. 90/260,418 01 Oct 1990; 2 pp. 93/4099 Process Metall. 1992 7A 457. 93/4104 Sci. Total. Environ. 1992 119 51. 93/4106 Sib. Khim. Zh. 1992 3 5. 9314107 Soil Sci. 1992 153 341. 9314109 Tech. Mess. 1992 59 147. 93/4121 Water Res. 1992 26 1163. 93/4122 Wood Fiber Sci. 1992,24 133. 93/4123 Yejin Fenxi 1992 12 53.

ISSN:0267-9477    

DOI:10.1039/JA994090025R

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 61 Dissociation of Analyte Oxide Ions in Inductively Coupled Plasma Mass Spectrometry E. Poussel and Jean-Michel Mermet Laboratoire des Sciences Analytiques Unite de Recherche Associee au Centre National de la Recherche Scientifique (URA 435) Batiment 308 Universite Claude Bernard-Lyon I 69622 Villeurbanne Cedex France D. Deruaz Laboratoire d'Etudes Analytiques et Cinetiques du Medicament Universite Claude Bernard Lyon I 69373 Lyon Cedex 08 France Analyte oxide ions have been studied in inductively coupled plasma mass spectrometry as a function of the sampling position the carrier gas flow rate and the efficiency of the energy transfer from the plasma to the sample in order to support the hypothesis of analyte oxide formation in the plasma.Lanthanum was selected as the test species owing to its high oxide bond strength and its behaviour was compared to that of Pb as this element has a low oxide bond strength. A prototype ICP mass spectrometer was used. The Laof Laf ratio was found to be in the 0.2-13000°/~ range under the operating conditions used. Energy transfer was either degraded by adding a sheathing gas or improved by adding hydrogen. The LaOf:La+ ratio was minimized for low carrier gas flow rates and an efficient energy transfer. This was corroborated by temperature optical measurements. The results are in good agreement with those found in other recent work. In any instance the role of the sampling position was found to be crucial in studying analyte oxide ion behaviour and optimizing analytical performance.Keywords Inductively coupled plasma; mass spectrometry; analyte oxide ion; mixed-gas plasma Inductively coupled plasma mass spectrometry (ICP-MS) has gained general acceptance because of excellent limits of detec- tion for most elements of the Periodic Table and the capability of measuring isotopic abundances. However ICP-MS suffers from some limitations. Among them the presence of isobaric interferences,' particularly those produced by analyte oxide ions MO' and argon oxide ions ArO+ which is a severe Possible isobaric interferences due to oxide ions have been reported.6 To a large extent the formation of oxide ions is made possible because of the presence of oxygen resulting from the dissociation of water contained in the aerosol.The amount of oxide can be reduced by using a sample introduction system that does not introduce water into the plasma such as electrothermal vaporization ( ETV).31,32 Solvent loading can be reduced by using a water-cooled spray ~ h a m b e r ~ ' ~ ~ or minimized with the use of a desolvation ~ y s t e m . ~ ~ ~ ~ The origin of oxygen is clear but the processes of analyte oxide formation are still the object of debate. Several explanations have been suggested (i) analyte oxides are formed in the plasma and are not fully d i ~ s o c i a t e d ; ~ ' ~ ' ~ ' ~ ~ (ii) they are formed in the boundary l a ~ e r ; ~ ~ and (iii) they are formed in the interface region between the sampler and the skimmer.'6*'8 Because of the large orifices currently used for the sampler it does not seem that the formation of oxides in the boundary layer is a predominant p r o ~ e s s .~ From the work of Douglas and it is unlikely that the formation of oxide occurs in the interface region. It is clear that analyte oxides are already present in the plasma itself as it is common knowledge that injection of rare earth elements (REE) into the plasma leads to the emission of oxide molecular bands. Most of the REE exhibit emission in the visible part of the spectrum. Spatial distribution of MO bandheads has been d e ~ c r i b e d ~ ~ . ~ ~ using emission spectrometry. Therefore it is likely that the observation of MO' is the result of both easy formation of the oxide along with incomplete further dissociation of the oxide in the plasma.It has been demonstrated that the MO+:M+ ratio is dependent on the operating parameters of the plasma such as the the carrier gas flow rate4-9,14,15,20,22 and the sampling position defined as the distance between the load coil and the aperture of the ~ a m p l e r . ~ * ~ * ~ . ' ~ . ~ ~ Usually an increase in the power and a decrease in the carrier gas flow rate result in reduction of oxide ion intensities which indicates the influence of the energy transfer from the plasma to the sample. However most of the experiments are performed at a fixed sampling position because of the difficulty of re-optimizing the lens voltages of the ion optics. Change in the carrier gas flow rate corresponds to both a variation in the amount of sample and the residence time.This results in a different optimum sampling position which is usually not taken into account. The MO+ M+ ratio can vary over a large range 0.001-0.3% for PbO+ Pb+,7.15916 0.63-360% for and 0.38-2% for UO+ U+.2,14,18*21 The MO+ M' ratio is also dependent on the oxide bond strength. Usually the greater the oxide bond strength the higher the ratio.",16,17,19,20'22 Addition of molecular gases35*39-43 with high thermal conduc- tivity such as N or H2 reduces the amount of oxide ions which is further evidence of the significant role of the energy transfer. To improve the understanding of analyte oxide formation and dissociation in the plasma investigations into the role of the efficiency of energy transfer have been undertaken. To obtain the spatial distribution of the various species scanning of the sampling position was performed for each value of the gas flow rates of concern. The efficiency of energy transfer was modified by varying the carrier gas flow rate.Furthermore the efficiency was either degraded by using a sheathing gas or improved by adding a molecular gas such as H,. This study was based on the use of a prototype TCP mass spectrometer designed to permit the user to vary easily the carrier gas flow rate and the sampling position. CeO+ Ce+,11,13,15,16,18,22 3.6-2400y0 for Lao+ La+,11.13.22 Experimental The prototype was based on the use of a 56 MHz ICP tuned- line generator and a Nermag R 1010 C mass spectrometer. The oscillator consisted of two parts (i) the first circuit where the high-frequency triode was set-up; and (ii) the second circuit where the coil was located.The transfer of energy between the two circuits was achieved by electromagnetic coupling through lines. There was therefore no grounding of the coil. The second circuit could move in front of the first one allowing62 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 40L. 9 the coil and consequently the torch to be positioned at various sampling positions through an x-y-z translation system. This ICP-MS system has been described p r e v i o u ~ l y . ~ ~ ~ ~ ~ The major features were (i) the use of a 6-turn load coil (26 mm long with an i.d. of 22mm) with a floating potential which resulted in the absence of any arcing at the sampler level; and (ii) very simple ion optics that consisted of a single 20 mm diameter high voltage extraction lens set up behind the skimmer and a quadrupole inlet ion.No photon stop was used. The extraction lens voltage was of the order of - 500 V. It was not found necessary to re-adjust the lens voltage for a variation in the carrier gas flow rate in the 0.5-1.0 1 min-' range. The sampler was made of nickel and had a 0.6mm diameter orifice. The skimmer was made of stainless steel and was 1 mm in diameter. The space between the sample and the skimmer was 8 mm. A cryogenic pump was used at the ion optics level (Edwards 1500 1 s-I). An analogue mode of detec- tion was used with a channeltron detector. The background was equivalent to 200 counts s-' if a digital readout was used. The operating parameters were a power of 1.2 kW an outer gas flow rate of 11 1 min-' a carrier gas flow rate in the 0.5-1 lmin-I range a sheathing gas flow rate in the 0-0.4 1 min-l range and a sampling position in the 2-35 mm range.When added hydrogen (0.02 1 min-') was mixed with the carrier gas. The Ar carrier and sheathing gas flow rates and the addition of H2 were controlled by Brooks 5878 mass flow controllers. A Meinhard type C pneumatic nebulizer was used in association with a double-pass spray chamber main- tained at room temperature to avoid drift of the oxide forma- tion. The inner diameter of the torch injector was 2 mm. A 1 m Jobin-Yvon THR monochromator equipped with a 3600 lines mm- holographic grating was used for temperature measurements by emission spectrometry. The practical reso- lution using slit-widths of 10pm and the second order of the grating was 1.7pm at 230nm.Side-on observation of the horizontal plasma was carried out through a Dove prism and a lens so that the axis of the plasma was vertically rotated and imaged on the vertical entrance slit of the monochromator. Use of a horizontal slit at the entrance slit level allowed a portion of the viewing zone to be selected. Temperature measurements were conducted based on the use of the Bolztmann plot of Ti I1 lines46 and the Doppler width of the Be I 234.86 nm line.47 Lead and La were selected as the test elements for this work based on the measurement of the 208 and 139 isotope signals respectively. They were selected owing to their large difference in oxide bond strength 4.32 eV and 8.24 eV respectively.48 Reactions leading to the formation of La' and Lao' and energies of dissociation of L a 0 and Lao' and ionization of La and L a 0 are summarized in Fig.l.48 Results Because of its low oxide bond strength PbO' is generally not observable in contrast to Lao' which is easily observed owing to its high bond strength. The behaviour of La+ Lao' and Pb' are therefore compared here. La0 La+O Lao' \ La+ +O Fig. 1 of ionization of La and La0 Energies (eV) of dissociation of L a 0 and Lao' and energies Effect of Carrier Gas Flow Rate and Sampling Position on Intensity of Pb' La' and Lao' An example of the effect of sampling position on the signal of Pb' for carrier gas flow rates in the 0.5-1.0 1 min-' range is shown in Fig. 2. For each flow rate there is an optimum of the sampling position leading to the maximum signal of Pb'.The location of the optimum is shifted away from the load coil as a function of the flow rate. The highest Pb' signal is obtained for a flow rate of 1.0 1 min-' and a sampling position of 8 mm. Even at 1.0 1 min-' the residence time is sufficiently long to fully dissociate PbO so that the maximum signal corresponds to the maximum amount of sample. The shift is explained by the higher velocity of the species in the plasma. However a different conclusion is observed for La+ where the formation of Lao' leads to a deterioration of the La' signal at high flow rates. The effect of sampling position on the signal of La' and Lao' for two extreme carrier gas flow rates i.e. 0.6 and 1.0 1 min-' is shown in Fig.3. In contrast to the results obtained for Pb' an increase in the amount of sample does not correspond to an increase in the La' signal owing to the presence of L a o + . Fig. 3 shows that the signal of Lao' is rather small at a carrier gas flow rate of 0.6 1 min-' whereas Lao' becomes the largest species at 1.0 1 min-'. Fig. 3 also shows that the formation zone of Lao' is closer to the injector than that of La'. From the same experiment it is possible to plot the L a o + La' ratio (Fig. 4) as a function of the sampling position for several carrier gas flow rates. The conditions for the observation of the optimum La' signal are also shown in Fig. 4. Under the operating conditions used for this experiment the Lao' :La+ ratio varies in the 0.2-13 000% range.The lowest La0':La' ratio is obtained for a carrier I 2 6 10 14 18 22 26 30 Sampling position/mm Fig. 2 Effect of the sampling position on the ion signal of Pb' for various carrier gas flow rates A 1.0; B 0.8; C 0.6; and D 0.5 1 min-' 1400 1200 - m .- u) .- 5 1000 a -5 ;s 800 C 5 I I \ \ \ 2 6 10 14 18 22 Sampling position/mm Fig.3 Effect of the sampling depth on the ion signal of La' (solid line) and Lao' (broken line) for two carrier gas flow rates D 0.6; and 0 1.01 min-lJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 63 1 x105 1 x 1 0 - ' 1 I I I I Sampling position/mm 1 5 9 13 17 21 Fig. 4 Effect of the sampling depth on the L a o t :La' ratio (%) for various carrier gas flow rates A 1.0; B 0.9; C 0.8; D 0.7; and E 0.6 1 min-'.The broken line is used to indicate the location of the maximum La+ signal gas flow rate of 0.6 1 min- ' i.e. the longest residence time and a sampling position of 12 mm. These conditions are far from being optimum for the determination of Pb'. When different species with a large range of oxide bond strengths are to be determined it is difficult to define compromise conditions without sacrificing either species with low oxide bond strengths or those with high ones. Examples are given in Table 1. Under the operating conditions used to obtain the lowest L a o + La+ ratio 10 and 30% of the maximum signal of Pb' and La+ are observed respectively. The optimum conditions for the La' signal lead to 30% of the maximum signal of Pb' whereas those for the optimum of the Pb+ signal lead to 15% of the maximum signal of La'.Nevertheless compromise conditions can be defined (Table l) which lead to at least 50% of the maximum analyte ion signals without too large an Lao+ signal. As stated earlier the increase in the Pb' signal is directly related to the increase in the amount of aerosol up to a carrier gas flow rate of 11 min-' because of the lack of oxide formation. Fig. 5 shows that there is good agreement between the signal of Pb+ and the amount of aerosol measured by trapping the aerosol on silica gel. The signal was integrated over the 2-30mm sampling position range. In contrast the same agreement is obtained for the La-containing species only when summing the Lao' and La' signals (Fig. 5). Clearly an increase in the carrier gas flow rate i.e.a decrease in the residence time and a degradation of the energy transfer efficiency enhances the formation of analyte oxides with a high bond strength. It is also clear that the study of the influence of the carrier gas flow rates for fixed values of the sampling position can lead to misleading conclusions. From the previous results it can be demonstrated that for a variation of the carrier gas flow rate between 0.8 and 1.0 1 min-' Lao' increases and La+ decreases for a 7mm sampling position whereas both Lao' and La+ decrease for a 3 mm sampling position. Therefore the sampling position is a significant parameter although its variation is not always easy to perform 0 ' I I I 1 ' 0 0.5 0.6 0.7 0.8 0.9 1 Carrier gas flow rate/l min ' Fig. 5 Comparison of the amount of aerosol (A) the Pb+ signal (B) the La' signal (C) and the sum of the La+ and Lao' signals (D) as a function of the carrier gas flow rate.Signals are integrated over a sampling position range of 2-30 mm with commercially available systems owing to the need for re-optimization of the ion optics lens voltages. Effect of the Sheathing Gas To confirm the drastic role of the efficiency of energy transfer on analyte oxide observation a sheathing gas has been added at the exit of the spray chamber. The main use of the addition of a sheathing gas is to prevent the deposition of material on the inner part of the injector. However the addition of a sheathing gas results also in a degradation of the efficiency of energy transfer,49 owing to the formation of a layer between the plasma and the central channel. The effect of the sampling position on the La' and Lao+ signal for a carrier gas flow rate of 0.6 or 1.Olmin-' and a sheathing gas flow rate of 0.4 1 min-' added to a carrier gas flow rate of 0.6 1 min-l is illustrated in Figs. 6 and 7.The addition of 0.41 min-' sheathing gas to 0.6 1 min-' of carrier gas does not modify the amount of sample obtained at 0.6 1 min-l without sheathing gas. However the degradation of the energy transfer has a Q 5 60 C 0 .- 40 m > Q .- L .- > 20 + - Q CT 2 7 12 17 22 27 32 37 Sampling position/mm Fig. 6 Effect of the sampling position on the La' signal for various carrier gas flow rates A 0.6; B 1.0; and C 0.6 1 min-' +0.4 1 min-' of sheathing gas. Signals were normalized to the maximum La+ signal Table 1 to different optimizations Percentage values of the maximum signal of Pb+ La' and Lao+ for various carrier gas flow rates and sampling positions corresponding Carrier gas/ Sampling Optimization 1 min-' position/mm Max Pb' (%) Max La+ (YO) Max Lao+ (YO) Lowest Lao + La + 0.6 Optimum La+ 0.6 Compromise conditions 0.8 Optimum Pb' 1 .o 12 5.5 8 7 10 30 100 50 30 100 15 62.5 0.025 1 46 9.264 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 - 100 .- Ln t 2 80 -I a 5 + 60 C 0 .- .I- L m 40 .- m !? 20 .- +- m a a - 0 Sa m pl i ng posit io n/m m Fig.7 Effect of the sampling depth on the Lao' signal for various carrier gas flow rates A 0.6; B 1.0; and C 0.6 1 min-' +0.4 1 min-' of sheathing gas. Signals were normalized to the maximum La+ signal drastic effect on both La' and Lao' signals.The peak intensity of La' is strongly decreased and shifted to a larger sampling position (Fig. 6) in marked contrast to the behaviour of Lao' (Fig. 7) whose intensity is strongly enhanced. For the same residence time i.e. a total flow rate of 1 1 min-' the intensity of La' also decreases and shifts because of a smaller amount of sample and a degradation of the energy transfer. Therefore both the residence time and the efficiency of the transfer of energy to the sample have a significant influence on the observation of analyte oxide. Addition of Hydrogen Argon exhibits poor thermal conductivity. Among molecular gases such as nitrogen oxygen and hydrogen hydrogen exhib- its the highest thermal conductivity below 10 000 K because of its dissociation near 3700 K." Potential advantages of adding hydrogen to improve the thermal conductivity of the plasma and consequently to enhance the efficiency of energy transfer have been discussed recently to aid the volatilization of slurrie~.~' Hydrogen requires additional energy for dis- sociation but does not modify the resistivity of the plasma and does not add new information to the ion spectrum as it is already present in the plasma.Molecular gases can be mixed with the outer gas resulting in shrinkage of the discharge and a corresponding increase in the temperature of the central channel. Alternatively molecular gases can be added to either the sheathing gas or the aerosol carrier gas. It has been demonstrated in atomic emission spectrometry that the addition of a small amount of hydrogen to the carrier gas or the sheathing gas can improve the transfer of energy particu- larly when the transfer has been degraded by having a short residence time or with the use of a sheathing gas.52 Addition of 0.021min-' of hydrogen was sufficient to modify signifi- cantly the spatial distribution of La+ and Lao+.It can be seen in Fig. 8 that the addition of hydrogen increases the rate of oxide dissociation so that the optimum of the Lao'. signal corresponds to a sampling position of t 2 mm i.e. in a region where the sampler cannot be located. The optimum of the La' signal is also observed (Fig. 9) for a lower value of the sampling position. It is important to note that similarly to the addition of a sheathing gas addition of hydrogen requires a re- adjustment of the sampling position to obtain the optimum conditions.Otherwise false conclusions might be deduced about the influence of the addition of hydrogen. Temperature Measurements The magnitude of ion signals of analyte oxides with a high bond strength is related to the temperature of the plasma. In order to relate the temperature of the central channel to the - 100 07 v) .- + % 80 1 0 5 60 u- 0 C ,g 40 m m .- L ; 20 .- 4- - Q U 0 5 10 15 20 25 30 35 Sampling positionhnm Fig. 8 Effect of the sampling position on the Lao+ signal for various carrier gas flow rates A 1.0; and B 0.98 1 min-' +0.02 1 min-' of hydrogen 0 5 10 15 20 25 30 35 Sam pl i ng posit i on/m m Fig.9 Effect of the sampling depth on the La+ signal for various carrier gas flow rates A 1.0; and B 0.98 1 min-'+0.02 1 min-' of hydrogen operating conditions used to degrade or enhance the energy transfer two different types of temperatures were measured the excitation temperature via the Boltzmann plot of ionic lines of Ti and the kinetic temperature using the Doppler line broadening of the Be 1 234.86 nm line.It was first verified that the presence of the interface close to the plasma did not significantly modify the temperature. A variation of less than 100 K was observed at the location of the tip of the sampler which meant that the presence of the sampler did not modify the thermal properties of the plasma under the range of conditions used in this work. Over a 2-20 mm observation position range the change in either the excitation temperature or the Doppler temperature was small with a maximum variation of 200 K.It was also found that the kinetic temperature was higher than the excitation temperature by about 2500 K. Spatially resolved temperature measurements would certainly be useful to pro- vide more information on the kinetics of oxide dissociation. However such measurements should be conducted by using Ar Lao Lao+ and La' species. As the oxide dissociation occurs all along the central channel it was preferred therefore to indicate the global changes in the temperature as an indicator of the behaviour of the plasma instead of providing spatially resolved measurements. The maximum values of L a o + and La' over the 2-20mm sampling position range and the corresponding ratio were compared with the global changes in excitation temperature and Doppler temperature using an observation volume over the 2-20mm sampling position range.Results are given in Fig. 10. Although the excitation differs from the kinetic temperature the behaviour of both temperatures as a function of the operating conditions is similar. From Fig. 10 it can be seen that the highestJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 65 I y0.6+0.4 4 0 . 6 + 0.4 I \ O!B + 0.OJ \ 0.98+0.02 \ \ \ I ; 1 1 0.6f0.2 .\i o.8 \ 0.6 + 0.2 2' o.8 1 \ \ \ 0.6 \ 0.6 0 I I I 3000 4000 5000 6000 7000 Excitation and Doppler temperatures Fig. 10 Effect of the excitation temperature (left) and the Doppler temperature (right) on the ratio of Lao' Laf ion signals. The ion signals were obtained by integrating the signal over the sampling position. All values are given in 1 min- '; 0.6 + 0.4 (or 0.6 + 0.2) means that 0.4 1 min-' (or 0.2) was added as a sheathing gas 0.98 +0.02 means that 0.02 1 min-' of hydrogen was added Lao' :La+ ratio is obtained at the lowest temperature. For a total injector gas flow rate of 11 min-' an increase in the temperature and a corresponding decrease in the Lao' La' ratio is observed first when the sheathing gas is suppressed and later when hydrogen is added to the carrier gas.A similar conclusion (Fig. 10) is reached when the sheathing gas flow rate decreases from 0.4 to 0.2 1 min-' or when the carrier gas flow rate decreases from 1 to 0.6 1 min-'. There is therefore a direct relation between the magnitude of the Lao' signal and the temperature of the central channel irrespective of the way the temperature is measured.This is further evidence that the observation of analyte oxides is related to the physical properties of the plasma. Conclusion Analyte oxide ions are mainly formed in the plasma during the dissociation of the sample and owing to the presence of oxygen produced by the dissociation of water. Hobbs and O l e ~ i k ~ ~ have clearly demonstrated that large droplets are not fully evaporated in the ICP. A decrease in the local temperature is observed in the vicinity of the droplets which aids the formation of analyte oxides. Recently Tanner54 has measured the kinetic energy of analyte and analyte oxide ions.A lower temperature of the analyte oxides was deduced from the measurements which indicated that the analyte oxide ions were formed in a cooler part of the plasma. Moreover,54 the oxide ion ratio was independent of the pressure at the interface which is further evidence that oxides are not formed during the extraction process. These results are consistent with the conclusions of Hobbs and O l e ~ i k . ~ ~ More efficient evaporation of the droplets and therefore a lowering of the analyte oxide signal can be obtained using a long residence time and a high energy transfer. In the instance where these conditions are not fullfilled large oxide ion signals are observed. The high carrier gas flow rate of 1.2 1 min-' along with an injector id. of 1.5 mm used originally with the first commercially available ICP-MS systems explains why high oxide ion:ion ratios were observed at this time.Careful optimization of the operating conditions such as the carrier gas flow rate and the sampling position results in an Lao' Laf ratio of the order of 0.2% with only a loss of a factor of 3 of the La' signal. The value of 0.2% is lower than that commonly observed with commercially available ICP-MS systems which is typically of the order of 1%. The value of 0.2% was obtained although the temperature of the plasma was not very high as a result of the selection of a high frequency (56 MHz) which was not beneficial for oxide dissociation. The addition of a molecular gas such as hydrogen increases the rate of analyte oxide dissociation. The only limitation is the need to work with a short sampling position which is not always possible with most commercially available systems.In any instance adjustment of the sampling position was found to be crucial both to minimize the analyte oxide formation although the system is only optimized for elements with a high oxide bond strength and to define compromise conditions for multi-elements analysis. Moreover the re-adjustment of the sampling position when other parameters are modified prevents false conclusions being reached about the behaviour of the various ionic species. Formation of analyte oxides is easy to observe in ICP-MS. However similar poor conditions of energy transfer can also be experienced in ICP atomic emission spectrometry when using low power and a high carrier gas flow rate.Emission of elements having oxides with a high bond strength can be similarly degraded because of the formation of the oxide to the detriment of the ion and consequently to the emission of ionic lines. This is an interference effect that has not been dealt with in emission spectrometry. It will be possible to study this effect with the use of a combined emission-ICP-MS system. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 References Evans E. H. and Giglio J. J. J. Anal. At. Spectrom. 1993 8 1. Gray A. L. and Date A. R. Analyst 1983 108 1033. Date A. R. and Gray A. L. Spectrochim. Acta Part B 1983 38 29. Olivares J. A. and Houk R. S. Anal. Chem. 1985 57 2674. Horlick G. Tan S. H. Vaughan M.A. and Rose C. A. Spectrochim. Acta Part B 1985 40 1555. Vaughan M. A. and Horlick G. Appl. Spectrosc. 1986 40 434. Long S. E. and Brown R. M. Analyst 1986 111 901. Gray A. L. J. Anal. At. Spectrom. 1986 1 247. Gray A. L. Spectrochim. Acta Part B 1986 41 151. McLeod C. W. Date A. R. and Cheung Y. Y. Spectrochim. Acta Part B 1986 41 169. Longerich H. P. Strong D. F. and Kantipuly C . J. Can. J. Spectrosc. 1986 31 11 1. Beauchemin D. McLaren J. W. Mykytiuk A. P. and Berman S . S. Anal. Chem. 1987 59 778. Lichte F. E. Meier A. L. and Crock J. G. Anal. Chem. 1987 59 1150. Boomer D. W. and Powell M. J. Anal. Chem. 1987 59 2810. Zhu G. and Browner R. F. Appl. Spectrosc. 1987 41 349. Gray A. L. and Williams J. G. J. Anal. At. Spectrom. 1987,2 81. McLaren J. W. Beauchemin D.and Berman S. S. J. Anal. At. Spectrom. 1987 2 277. Wilson D. A. Vickers G. H. and Hieftje G. M. J. Anal. At. Spectrom. 1987 2 365. Hutton R. C. and Eaton A. N. J. Anal. At. Spectrom. 1987,2,595. Gray A. L. and Williams J. G. J. Anal. At. Spectrom. 1987,2,599. Price Russ 111 G. and Bazan J. M. Spectrochim. Acta Part B 1987 42 49. Longerich H. P. Fryer B. J. Strong D. F. and Kantipuly C. J. Spectrochim. Acta Part B 1987 42 75. Gordon J. S. van der Plas P. S. C. and De Galan L. Anal. Chem. 1988 60 372. Longerich H. P. J. Anal. At. Spectrom. 1989 4 491. Vaughan M.-A. and Horlick G. J. Anal. At. Spectrom. 1989 4 45. Vaughan M.-A. and Horlick G. Spectrochim. Acta Part B 1990 45 1289. Ross B. S. Yang P. and Hieftje G. Appl. Spectrosc. 1991,45 190. Lepla K. Vaughan M.A. and Horlick G. Spectrochim. Acta Part B 1991 46 967. Norman L. A. Munoz M. Myers D. P. Ross B. S. and Hieftje G. M. Appl. Spectrosc. 1992 46 3. Crain S. J. and Gallimore D. L. Appl. Spectrosc. 1992 46 547. Hall G. E. M. Pelchat J. C. Boomer D. W. and Powell M. J. Anal. At. Spectrom. 1988 3 791. Shibata N. Fudagawa N. and Kubota M. Anal. Chem. 1991 63 636. Zhu G.-X. and Browner R. F. J. Anal. At. Spectrom. 1988,3,781.66 34 35 36 37 38 39 40 41 42 43 44 45 JOURNAL OF ANALYTICAL Tsukahara R. and Kubota M. Spectrochim. Acta Part B 1990 45 581. Lam J. W. and McLaren J. W. J. Anal. At. Spectrom. 1990 5 419. Douglas D. J. and French J. B. J. Anal. At. Spectrom. 1988 Furuta N. Spectrochim. Acta Part B 1986 41 1115. Li. K. P. Dowling M. Fogg T. Yu T. Yeah K.S. Hwang J. D. and Winefordner J. D. Anal. Chem. 1988 60 1590. Vaughan M. A. and Horlick G. Spectrochim. Acta Part B 1990 45 1313. Beauchemin D. and Craig J. M. Spectrochim. Acta Part B 1991 46 603. Wang J . 3 Evans E. H. and Caruso J. A J. Anal. At. Spectrom. 1992 7 929. Craig J. M. and Beauchemin D. J. Anal. At. Spectrom. 1992 7 937. Louie H. and Soo S. Y.-P. J. Anal. At. Spectrom. 1992 7 557. Allain P. Mauras Y. Douge C. Jaunault L. Delaporte T. and Beaugrand C. Analyst 1990 115 813. Allain P. Jaunault L. Mauras Y. Mermet J. M. and Delaporte T. Anal. Chem. 1991 63 1497. 3 743. 46 47 48 49 50 51 52 53 54 A LTOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 Mermet J. M. in Inductively Coupled Plasma Emission Spectroscopy Part 11 Applications and Fundamentals ed. Boumans P. W. J. M. Wiley New York 1987 ch. 10 p. 353. Boumans P. W. J. M. and Vrakking J. J. A. M. Spectrochim. Acta Part B 1986 41 1235. Ackerman R. J. Rauh E. G. and Thorn R. J. J. Chem. Phys. 1976 3 1027. Murillo M. and Mermet J. M. Spectrochim. Acta Part B 1987 42 1151. Pateyron B. Elchinger M. F. Delluc G. and Fauchais P. Plasma Chem. Plasma Process. 1992 12 421. Ebdon L. and Goodall P. J. Anal. At. Spectrom. 1992 7 1111. Murillo M. and Mermet J. M. Spectrochim. Acta Part B 1989 44 359. Hobbs S. E. and Olesik J. W. Spectrochim. Acta Part B 1993 48 817. Tanner S. D. 76th Canadian Society for Chemistry Conference Sherbrooke 1993 paper 79. Paper 3/04207C Received July 19 1993 Accepted November 4 1993

ISSN:0267-9477    

DOI:10.1039/JA9940900061

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 67 Rapid Survey Analysis of Polymeric Materials by Laser-induced Plasma Emission Spectrometry* David R. Anderson and Cameron W. McLeod Division of Chemistry School of Science Sheffield Hallam University Sheffield UK S 7 7 WB Trevor A. Smith Arun Technology Limited Unit 7 6 South water Industrial Estate Station Road South water Horsham Sussex UK RH 13 7UD Laser-induced plasma emission spectrometry has been applied to the analysis of poly(viny1 chloride) mate- rials. Methodologies used to optimize the monitoring of the time-dependent emission from the laser-induced plasma are discussed and the effects of key parameters such as laser energy sample position and repetitive firing at given sites were examined. Basic performance data are reported for Ca [limit of detection 0.016% m/m and 4.8% relative standard deviation (RSD)] and Sb (limit of detection 0.04% m/m and 4.8% RSD) and the potential use for rapid survey analysis is demonstrated.Keywords Laser-induced plasma emission spectrometry; gated diode array detection; laser ablation; polymer analysis Polymeric materials generally contain a wide variety of addi- tives which are used to give specific properties to the material.' These include pigments for colour (e.g. white Ti02) fillers (e.g. CaCO,) stabilizers (e.g. Zn Pb and Ba) flame-retarding agents (e.g. Sb P) and smoke suppressants (e.g. Zn) among others. These inorganic components vary in concentration from trace (pg g-') to minor (%) levels. Analytical techniques currently in use for such analyses include solution-based atomic spectrometric and X-ray fluorescence spec- t r ~ m e t r y .~ An alternative approach is direct spectrochemical analysis by laser ablation (LA) either by direct spectral measurement of the laser-induced plasma or by coupling to another analytical technique. For example LA with inductively coupled plasma (ICP) atomic emission spectrometry has been used for survey analysis of paints and polymer^,^ while ICP mass spectrometry has been applied to polymeric and refrac- tory materiak6 Direct spectrochemical measurement of the plasma laser- induced plasma emission spectrometry (LIPS) enables rapid in situ analy~is,~.' and is particularly suited to process measure- ment.' The emission signals from the laser-induced plasma are complex and vary greatly with time.Time-resolved measure- ment is usually essential for the separation of the analyte emission response from the intense plasma background." Basic characterization of the laser-induced plasma and systematic studies concerning the effect of key parameters such as the wavelength of the laser light and the type and pressure of the buffer gas have been reported.''-16 Niemax et a2.,I6 concluded that a wavelength of 1064 nm was more suitable than 266 nm for analysis of glass and steel matrices. Other workers's'5 found that a reduced pressure of Ar gas typically 133.32 x lo3 Pa offered improved analytical performance. For process monitoring situations where it may not be feasible to achieve partial pressures atmospheric pressure has been used.Cremers and Archuleta' reported the in situ measurement of molten steel for five elements (Ni Cr Si Mn and Cu) using a laser wavelength of 1064nm by LIPS and LA-ICP and concluded that at least semiquantitative analysis was feasible. Lorenzen et a1.17 described the in situ monitoring of S Si and Zn in rubber production using an excimer laser operating at 248 nm and discussed the choice of laser wavelength for this application. The present study examines the application of LIPS to the *Presented in part at the 1993 European Winter Conference on Plasma Spectrochemistry Granada Spain. January 10-15 1993. rapid survey analysis of poly(viny1 chloride) (PVC) samples and provides information about the emission characteristics of the laser-induced plasma in particular the emission-time pro- files of analyte and background emission.Basic performance data for the determination of Sb Ca and P in PVC samples are presented. Experimental Instrumentation A schematic diagram of the LIPS system is shown in Fig. 1 and details of the instrumentation and operating parameters are given in Table 1. The system consisted of a Q-switched Nd:YAG laser with output wavelength of 1064 nm an optical multi-channel analyser (OMA) that comprised a spectrometer an intensified photodiode array (PDA) detector a com- puterized control system and a master pulse generator. Operation of the laser and the OMA was synchronized elec- tronically using the master pulse generator. This controlled the timings of the laser flash lamp and Q-switched laser firing and the detector gating and scanning of the detector array.Both the laser flash lamp and the OMA detector were operated at 10Hz. The laser was fired during alternate flashes of the flash lamp i.e. at 5 Hz and the OMA recorded a blank spectrum during the flash lamp cycles when the laser did not fire. Each blank spectrum was automatically subtracted from Laser Mirror 1064 nm r Pulse generator P ,rk+?Qbro asrn a Fibre optic Fig. 1 Schematic diagram of laser and spectrometer system68 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 Table 1 Instrumentation and parameters used in this study Laser Spectra Physics DCR I1 Wavelength 1064 nm Repetition rate 10 Hz Laser flash lamp energy Pulse-width 10 ns Reflecting mirror Focus lens Ablation gas Sample position (relative to laser focal point) Spectrometer 0.28 m Czerny-Turner Grating 2400 g mm-' Spectral window 25 nm Effective resolution 0.20 nm Detector Intensified photodiode array Light collection and transfer 40 J 45" (Newport 10 QM 20 HM-15) 500 mm focal length (Newport SBX 040 AR.18) Air at room temperature and pressure -0.5 mm (0.5 mm towards lens) OMA EG&G OMA I11 Fibre optic bundle of 19 x 200 pm UV-grade fused silica Fibre optic observation position From laser focal point Above sample surface 1 mm 12 mm Pulse generator EG&G 1310 the previous emission spectrum to yield a net signal from the plasma.The run time for 5 laser shots was 1 s. Laser light was delivered to the sample by a mirror and a lens was used to focus the light onto the sample surface.The laser-induced plasma was formed at the surface of the sample and radiation was transmitted to the OMA by a fibre optic cable. The light was dispersed by the grating of the spec- trometer and detected by an intensified photodiode array. The detector was time-gated to allow precise control of the inte- gration time. Various spectral regions could be monitored by setting the grating to the required centre wavelength. This was controlled by the grating-drive mechanism which rotated the grating until the required wavelength window covered the detector elements. Three spectral windows 237-262,267-292 and 307-332 nm of centre wavelengths 250 280 and 320 nm respectively were used to detect the elements selected (Al Ba Ca Cu Fe Mg Pb P Sb Sn Ti and Zn).The emission lines monitored are given in Table2. In addition two barium lines were utilized (230.423 and 233.527 nm) at centre wavelength 230 nm. Data Acquisition The OMA hardware and software allowed versatile collection storage and manipulation of data. For example individual scans of the photodiode array representing separate laser shots could either be stored in separate memories or accumu- lated into a single memory. The time-gating capability of the OMA was used in two ways to address the problem of complex time-dependent emission from the laser-induced plasma. Two data acquisition modes of OMA operation are described below incremental mode and fixed time mode (FT). An incremental program was used for preliminary studies in which each scan of the array was stored in a separate memory and the integration window (100 ns) was stepped sequentially through the lifetime of the plasma by the increment time (100 ns).This enabled the spectra to be time-resolved to produce an emission- wavelength-time (E-W-T) profile of emission from the plasma. Examination of the transient signal responses within these profiles enabled suitable values for delay and integration times to be selected for use in an FT program. The FT data acquisition mode exploited the separation in time of the analyte response from the background signal and allowed greater measurement sensitivity to be realized. Here Table 2 List of element emission lines for each spectral window monitored in this study Wavelength range/nm 237-262 240.549 Cu 241.949 Sn 247.857 C I 250.200 Zn I1 250.911 C I1 251.203 C I I 251.743 Ti I1 252.560 Ti I1 252.852 S b I 253.401 P I 253.565 P I 254.480 Cu I1 255.328 P I 255.493 P I 255.796 Zn I1 256.253 FeII 259.806 S b I 259.881 Cu I1 261.418 Pb 267-292 279.553 Mg I1 280.199 P b I 280.270 Mg I1 283.304 P b I 283.999 S n I 285.213 MgI 286.333 S n I 286.426 Pb 287.792 S b I 307-332 308.215 A11 308.802 Ti I1 309.271 A11 315.887 C a I I 317.502 S n I 317.933 C a I I 322.579 Fe I1 322.775 Fe I1 323.252 S b I 323.452 Ti I1 323.612 Ti I1 323.904 Ti I1 324.199 Ti I1 324.754 C u I 326.233 S n I 326.751 S b I 327.396 C u I 328.233 Z n I 328.321 Sn I1 330.259 Z n I the start of integration was delayed by a set time the delay time to enable rejection of the initial intense background signal and the integration period captured the analyte emission signal response; typical parameters were delay time 500 ns and integration time 1 ps.Two FT programs FT1 and FT2 were used to acquire the laser generated spectra. Method FT1 consisted of firing 30 laser shots at the same spot each shot being stored individually i.e. 1 scan in 30 memories (30 scans total). Method FT2 accumulated five laser shots into one memory at one sample site and this was repeated seven times in total with a fresh site each time i.e. 5 scans in 7 memories (35 scans total). The run times for FT1 and FT2 were 6 and 7 s respectively with a further 25 s required for sample translation for FT2. Materials Poly(viny1 chloride) samples (A-F) were supplied in sheet form by FMC Process Additives (UK).Sample X was industrial grade PVC (Darvic) obtained locally. Procedure Samples were analysed as received with no sample preparation. The sample was mounted on an XYZ manipulator and a fresh area of material postioned at the laser spot. The manipulator was moved in height (2) until the sample was at the laser focal point 500 mm from the focusing lens and then moved 0.5 mm towards the lens. With the laser operating at a suitable flash lamp energy e.g. 40 J the acquisition was started. The laser fired under control of the OMA software and the master pulse generator and the resulting scans were stored on the computer and printed. Separate routines were used off-line to perform individual pixel analyses to give emission-time profiles and statistical information.Results and Discussion Preliminary Studies Previous studies1* of LIPS with metallurgical samples found that emission signal responses and analytical performance were greatly influenced by the complex interdependent relationship of several parameters e.g. laser energy sample position relative to laser focal point position of the fibre optic and OMAJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 Fig. 2 Talysurf stylus-profile of a crater in PVC (sample X) produced by ten laser shots laser flash lamp energy 40 J. The profile was recorded by 164 scans in a 1.63 mm square grid detector settings. For example ablation with a relatively high laser energy (flash lamp energy 70 J irradiance x3.1 x 10" W cmP2) produced a more intense longer-lived plasma that required a different fibre optic viewing position and OMA settings for optimal performance compared with ablation with a lower energy (flash lamp energy 40 J x8.0 x 10'' W crnT2).For this preliminary study with poly- meric materials initial selection of laser lamp energy was made by examining the amount of laser-damage .to the sample and the variation in emission intensity produced by different values of laser energy. For optimum LIPS performance it may be necessary to characterize the experimental parameters listed above for the ablation of polymeric materials and also consider the effects of polymer properties such as transparency and colour upon ablation. A relatively low laser energy (flash lamp energy 40 J) was chosen which inflicted minimal laser damage to the sample but produced suitable emission responses.The laser appeared to couple well with coloured opaque samples. A Talysurf stylus-profile of the crater produced in PVC (sample X) by ten laser shots is depicted in Fig. 2. It shows the round crater to be approximately 1 mm in diameter and 50 pm deep. A dark- t B h > v) c a3 c c 0 v) v) w c .- c .- .- .- E 1 307 319 3 Wavelengthlnm 69 12 Fig. 3 LIPS spectra for ablation of A Ti metal; and B PVC sample X (laser flash lamp energy 40 J). OMA parameters delay time 900 ns; integration time 100 ns ened region about 2mm in diameter was observed around each crater. The LA of an opaque polymer was compared with the ablation of metal using conditions previously established for metal samples. Fig. 3 depicts spectra from the ablations of sampleX and Ti metal taken from the respective E-W-T profiles.The spectra are very similar and most emission lines can be identified as Ti indicating the presence of Ti in the polymer probably as the pigment titanium dioxide. The spec- trum for the polymer is more intense than that for the metal probably due to a combination of factors such as greater coupling of the laser and plasma with the polymer and the lower temperatures needed for volatilization and decompo- sition of the polymer compared with the metal. In the case of transparent polymeric samples no emission signals were obtained when material was ablated with the operating parameters specified under Experimental. Faint tun- nelling through the material and ablation of the metal support underneath the sample were observed.This would suggest that a plasma was not induced on the surface of the polymer and that the laser light was transmitted through the plastic to the metal. The tunnelling was due to the self-focusing of the laser t ~. - - Wavelength - / 1 Fig. 4 Emission-wavelength (237-262 nm)-time (0-900 ns) profile for ablation of sample A using the Incremental program (increment time 100 ns; integration time 100 ns) A carbon I 247.9 nm; and B carbon I1 250.9 and 251.2 nm; C antimony 252.9; and D phosphorus 253.4 and 253.5 nm70 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 140 I 1 0 400 800 1200 1600 2000 Delay timehs Fig.5 Emission-time profile for ablation of sample A with the Incremental program (increment time 100 ns; integration time 10011s) A carbon I 247.9; B antimony 252.9; C phosphorus 253.4; and D background 245.0 nm beam within the material which trapped the light and pre- vented it from spreading to produce a waveguide.'' This was not evident in the opaque samples because the laser light was absorbed leading to ablation and production of the laser- induced plasma.When the transparent sample was moved away from the laser focus position i.e. 3 mm away from the lens (+ 3 mm) emission signals and laser damage on the sample surface were observed. The plasma was induced in the air above the sample surface and the plasma was responsible for volatilizing sample material and creating the crater. Results indicated that it was feasible to gain elemental composition data from transparent polymer material.These conditions were not adopted for opaque samples because greater damage was inflicted upon these materials without any significant improve- ment in performance. An E-W-T profile recorded with the OMA incremental program from the ablation of sample A (Fig. 4) shows the intense background continuum at early times and the emerg- 400 I/ L .- 0 v) c 2500 E 2000 .- .- - w 1500 C D -.-.- -.._.._.. _..- ..-*.- 500 1 ..-.._.._.._.._.._.._.. -..-.. E _-- - - - - - - - - - _ _ _ _ _ _ _ _ _ - I I I 1 I L 0 1 2 3 4 5 6 Memory No. Fig.6 Emission-time profile for ablation of sample A with FT program (delay time 500 ns; integration time 1 ps) (a) FT1 30 shots at same spot; and (b) FT2 5 shots in each memory 7 memories fresh site each memory A carbon I 247.9; B antimony 252.9; C antimony 259.8; D phosphorus 253.4; and E background 245.0 nm ence of atom/ion emission at later times.Carbon ion emissions (250.9 251.2 nm) were evident initially and carbon atom emissions (247.9 nm) later. The intense background signal and carbon ion emissions reflect the high temperatures of the plasma at early times but as the plasma expanded and cooled the background signal decayed rapidly and atomic emission lines for Sb and P became prominent. An E-T profile for selected wavelengths (Fig. 5) shows the responses of C Sb and P to be indistinguishable from the background up to 400ns. After this emission signals for these three elements remain above background up to about 1.5 ps. These observations enable suitable detector settings to be obtained for the FT data acquisition mode; the background signal is reduced significantly by 500ns so selection of a time delay of 500ns would minimize background contributions and a signal inte- gration of 1 ps would be appropriate for monitoring analyte emission.Analytical Performance Full quantitative measurement of inorganic additives in poly- meric materials is considered to be difficult because of the absence of suitable certified reference materials (CRMs) neces- sary to prepare calibration graphs. Quantitative measurements in this work are based on using characterized samples as calibration standards. To obtain analytical performance data OMA FT programs were devised using the system operating parameters established above. Initial studies used two FT programs FT1 and FT2 to examine the effect of repetitive firing of the laser on signal response and to test for sample homogeneity prior to making performance measurements.Results from the ablation of sample A by both methods are shown in Fig. 6 (laser flash lamp energy 40 J delay time 500 ns integration time 1 ps). With FT1 the Sb emission responses were not similar throughout the experiment although the C and P emission signals were reasonably constant. Both Sb lines increased in intensity at first and then decreased until A t >- v) C al C C 0 v) v) 4- .- 4d .- .- .- E w Wavelength --c Fig. 7 Emission-wavelength (237-262 nm)-memory number profile for ablation of sample A with FT2 with delay time 500 ns; integration time 1 ps 5 shots in each memory 7 memories fresh site each memory A carbon I 247.9; B antimony 252.9; and C antimony 259.8 nm Table 3 Comparison of data from fixed time methods FT1 and FT2 for the ablation of sample A Parameter No.of shots per site RSD C 247.8 nm RSD Sb 252.8 nm RSD P 253.4 nm S/N (P 2.6%) Value of n for statistical calculation S/N (Sb 4.9%) Method FT1 30 10.6 29.7 6.9 13.4 4.5 30 Method FT2 5 4.8 4.8 7.0 97 33 7JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 71 1000 about memory number 9 after which a relatively constant signal response was observed. Emission responses for all elements were fairly constant with FT2 [Fig. 6(b)]. The emission response for Sb was not linear with concen- tration for method FT1 but FT2 did produce a linear response.It would appear that the Sb in the vicinity of the laser spot was selectively volatilized during the first few laser shots possibly through formation of volatile antimony chloride leading to a depletion of Sb for the remaining shots. The effect was not due to higher concentration levels of Sb at the surface as similar E-T profiles were obtained from the ablation of material beneath the sample surface. Use of a small number of laser shots i.e. five on several sites with method FT2 enabled a linear calibration to be produced. Reasonably con- stant signals for C Ca and P were obtained by FT1 suggesting that these elements were not selectively volatilized and it was still possible to make representative measurements after firing 30 laser shots at the same site.The emission responses for C and Sb were more reproducible Mg Sn - n L - 3000 I 3000 1500 A v) C 3 0 ). CI - Y C 01 .- 3000 C 0 cn .- .- E W 1500 3000 1500 n C C 237.0 2000 1000 0 2500 1250 with method FT2 compared with FT1. An emission-wave- length-memory number profile (Fig. 7) for ablation with FT2 clearly indicates good repeatability for successive laser firings and results suggest that the sample is relatively homogeneous. Precision [relative standard deviation (RSD)] improved from 10.6 and 29.7 (FTl) to 4.8 and 4.8 (FT2) for C and Sb respectively but there was no significant change for phos- phorus RSD 6.9 (Table 3). Using the C signal (247.86 nm) as an internal standard RSD was further improved to 2.3 and 3.4 for Sb and P respectively. This approach is only applicable for element emission signals that are within the spectral region 237-262 nm that contains a C emission signal.The signa1:noise ratio for C Sb and P was considerably improved using FT2 due to the accumulation of five laser shots into each OMA memory compared with one shot with FT1. Using method FT2 linear calibration graphs were generated for Sb (to 4.9% m/m) and Ca (to 6.8% m/m) emissions (Sb 252.8 and 258.8 nm; Ca 315.9 and 317.9 nm) with three data points for each element. The correlation coefficients were 8oo 1 2ooo i- 2ooo I 800 400 Ca 800 400 n Al 262.0 267.0 292.0 307.0 Wavelengthh m 332.0 Fig. 8 Laser-induced plasma emission spectra from samples A B D and E (from top to bottom). Spectra were recorded with fixed time method FT2 delay time 500 ns integration time 1 ps 5 shots in each memory 7 memories fresh site each memory.Emission wavelengths are given in Table 272 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 0.9936 and 0.9999 for Sb 259.8 nm and Ca 317.9 nm respect- ively. Limits of detection based on 30 (measurement of blank PVC sample) were estimated at 0.04 and 0.016% m/m for Sb 252.8 nm and Ca 317.9 nm respectively. The data are similar to values obtained for elements in steel (Ni Cr Si and Mn) by Cremers and Archuleta’ using LIPS. Survey Analysis To demonstrate the rapid analysis capability a range of PVC samples was examined. (The composition values quoted were supplied by the manufacturer.) Spectra from four samples are shown in Fig. 8 for three spectral regions. Samples A and B are clearly seen to contain Sb as the emission lines for Sb are identified within all three spectral windows for both samples.The greater emission intensity for A compared with B indicates the higher concentration present in A (Sb A 4.9% m/m; B 2.8% m/m). Tin and P are present in sample A (P 2.6% m/m Sn 0.05% m/m). Calcium emission lines are evident in samples B and D the greater emission intensity of B indicating the higher concentration present (Ca B 6.8% m/m; D 0.4% m/m). Emission lines of magnesium were observed for all four samples. Barium was detected in samples B (Ba 0.1% m/m) the Ba emission lines (230.423 and 233.527 nm) are not shown in Fig. 8. Lead (3.0% m/m) is present in sample D and Al P Sn and Zn are evident in E. Samples C and X (not shown) contain Sn and Zn and Ti and Mg respectively. These results show that the technique can be used for the rapid analysis of samples of PVC for a range of elements without the need for time-consuming sample dissolution and possible loss of volatile elements.Conclusions Laser-induced plasma emission spectrometry has been applied to the rapid survey analysis of polymeric materials. This study monitored a range of twelve elements (Al Ba Ca Cu Fe Mg Pb P Sb Sn Ti and Zn) and provided analytical data for key elements (Sb and Ca). Quantitative measurement was limited by the availability of characterized samples. To address this problem it is proposed to prepare a series of samples covering a wide range of concentration levels for selected elements which will enable additional calibrations and further quantitative measurements to be made.The speed of analysis compactness of instrumentation and simplicity of operation suggest that the technique has the potential for compositional monitoring of polymeric materials in industrial processes such as manufacture and recycling. We would like to thank Richard Dellar (FMC Corporation Manchester UK M17 1WT) for providing samples. We are grateful to Richard Burdett (EG&G Sorbus House Wokingham UK) for valuable assistance in configuring the OMA system. We thank Mike Simpson for helpful discussions and Mac Jackson (School of Engineering) for the talysurf analysis. The authors thank the DTI and SERC for funding this project under the LINK TAPM scheme. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 References Plastic Additives Handbook eds. Gachter and Muller Hanser 1983.Wong K. L. Anal. Chem. 1981 53 2148. DiPasquale G. and Casetta B. At. Spectrosc. 1984 5 209. Warren P. L. Anal. Proc. 1990 27 186. Booth P. K. and McLeod C. W. Mikrochim. Acta 1989 3 283. Marshall J. Franks J. Abell I. and Tye C. J. Anal. At. Spectrom. 1991 6 145. Moenke-Blankenburg L. Laser Micro Analysis Wiley 1989. Laser-induced Plasmas and Applications eds. Cremers D. A. and Radziemski L. J. Marcel Dekker New York 1989. Cremers D. A. Archuleta F. L. and Dilworth H.C. Proceedings of the 5th Process Tech. Con$ on Meas. and Control Instrum. in the Iron and Steel Industry April 14-17 1985 pp. 157-162. Iron and Steel Society Warrendale PA USA. Cremers D. A. and Radziemski L. J. in Applications of Laser Spectroscopy eds. Cremers D. A. and Radziemski L. J. Marcel Dekker New York 1986 ch. 5 pp. 380-395. Niemax K. Leis F. Sdorra W. and KO J. B. Mikrochim. Acta 1989 2 185. Niemax K. KO J. B. and Sdorra W. Fresnius’ Z . Anal. Chem. 1989 335 648. Niemax K. and Sdorra W. Mikrochim. Acta 1992 107 319. Iida Y. Anal. Sci 1991 7 61. Kuzuya M. and Mikami O. J. Anal. At. Spectrom. 1992 7 493. Niemax K. Sdorra W. and Brust J. Mikrochirn. Acta 1992 108 1. Lorenzen C. J. Carlhoff C. Hahn U. and Jogwich M. J. Anal. At. Spectrom. 1992 7 1029. Anderson D. R. and McLeod C. W. unpublished work. Ready J. F. EfSects of High Power Laser Radiation Academic Press New York 1971. Paper 3/02845C Received May 19 1993 Accepted November 8 1993

ISSN:0267-9477    

DOI:10.1039/JA9940900067

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

72 R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 Glossary of Abbreviations Whenever suitable elements may be referred to by their chemical symbols and compounds by their formulae. The following abbreviations are used extensively in the Atomic Spectrometry Updates. a.c. AA AAS AE AES AF AFS AOAC APDC ASV BCR CCP CMP CRM cv cw d.c. DCP DDC DMF DNA ECD EDL EDTA EDXRF EIE EPMA ETA ETAAS ETV EXAFS FAAS FAB FAES FAFS FI FPD FT FTMS GC GD GDL GDMS Ge( Li) HCL h.f. HG HPGe HPLC IAEA IBMK ICP ICP-MS ID 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-stripping voltammetry Community Bureau of Reference capacitively coupled plasma capacitively coupled microwave plasma certified reference material cold vapour continuous wave direct current d.c.plasma diethyldithiocarbamate N N-dimeth ylformamide deoxyribonucleic acid electron capture detection electrodeless discharge lamp ethylenediaminetetraacetic acid energy dispersive X-ray fluorescence easily ionizable element electron probe microanalysis electrothermal atomization electrothermal atomic absorption spectrometry electrothermal vaporization extended X-ray absorption fine structure flame AAS fast atom bombardment flame AES flame AFS 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-one) inductively coupled plasma inductively coupled plasma mass spectrometry isotope dilution (ammonium pyrrolidin- 1 -yl dithioformate) spectroscopy IR tUPAC LA LC LEAFS LEI LMMS LOD LTE MECA MIP MS NAA NaDDC NIES NIST NTA OES PIGE PIXE PMT PPm PTFE r.f.REE(s) RIMS RM RSD SEC SEM SFC Si( Li) SIMAAC SIMS SR SRM SSMS STPF TCA TIMS TLC TMAH TOP0 TXRF u.h.f. uv VDU vuv WDXRF XRF PPb QC S/B SIN infrared International Union of Pure and Applied Chemistry laser ablation liquid chromatography laser-excited atomic fluorescence spectrometry laser-enhanced ionization laser-microprobe mass spectrometry limit of detection 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 nitrilotriacetic acid optical emission spectrometry particle-induced gamma-ray emission particle-induced X-ray emission photomultiplier tube parts per billion parts per million polytetrafluoroethylene quality control radiofrequency 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 total reflection X-ray fluorescence ultra-high frequency ultraviolet visual display unit vacuum ultraviolet wavelength dispersive X-ray fluorescence X-ray fluorescence Technology

ISSN:0267-9477    

DOI:10.1039/JA994090072R

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 73 Determination of Oxygen-containing Additives in Gasoline by Gas Chromatography-Microwave-induced Plasma Atomic Emission Spectrometry Scott R. Goode and Christopher L. Thomas Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA The development and characterization of a method for the determination of oxygen-containing (oxygenated) species in a complex mixture of hydrocarbons is described. A microwave-induced plasma (MIP) atomic emission detector is coupled to a gas chromatograph and atomic oxygen emission is monitored as an indication of oxygenated compounds in the gas chromatograph effluent. On-line helium purification and the use of a tangential-flow torch provide conditions ideal for oxygen-selective analysis without make-up gases or extensive background correction.Furthermore large amounts of solvent or sample do not extinguish the plasma so samples can be analysed directly without dilution addition of reagent gases or solvent venting procedures. Both axial and lateral viewing positions were investigated for analytical use. Detection limits for oxygen were 1 ng s-' for both axial and lateral positions but sensitivity was higher in the axial position. However selectivity over carbon in the lateral position was 4850 1 compared with 155 1 in the axial position. The gas chromatography MIP method was applied using lateral viewing to the analysis of alcohols in National Institute of Standards and Technology (NIST) reference fuel standards and to commercial gasoline samples collected from Columbia SC USA and Greensboro NC USA.Experimental results of oxygen- selective analysis of NIST reference fuel are in good agreement with the certified values. Results obtained for the determination of oxygenated compounds in gasoline samples further demonstrate the usefulness of the method for the analysis of a complex mixture of hydrocarbons. Most spike recoveries were within 10% of the expected values. Examples of oxygen-selective chromatograms are presented to demonstrate the usefulness and selectivity of the method. Keywords Oxygen-selective detection; gasoline analysis; microwave-induced plasma; gas-chromatographic detector; atomic emission spectrometry The Clean Air Act of 1990 mandates the use of oxygen- containing (oxygenated) gasoline in several US cities to reduce harmful automobile carbon monoxide and ozone emissions.' Among the top choices for oxygenated additives are tert- butylmethylether (TBME) ethanol and methanol.While these components are easily identified and quantified in most matrices by gas chromatography (GC) their determination in gasoline presents a particular challenge to the analytical chemist. In GC the peaks due to oxygenated compounds frequently overlap with those from the hydrocarbon constituents of the gasoline. The conventional solution to this problem is to improve the resolution of the GC separation. American Society for Testing and Materials (ASTM) method D4815 specifies a dual column separation procedure in which a polar column is used to trap the oxygenated compounds followed by a back- flush step.2 Other work has focused on improving the reso- lution of a single capillary column with a goal of baseline separation to identify the oxygenated compound^.^ While these methods are certainly reliable and accurate they require long analysis times. Another approach to measuring concentrations of oxygen- ated compounds in gasoline is to develop a selective GC detector that responds only to compounds that contain oxygen.Three types of oxygen-selective GC detectors have been described. The oxygen-flame ionization detector (0-FID) con- verts oxygenated compounds in a catalytic reactor first into carbon monoxide and then into methane which is easily detectable by conventional FID. The absolute detection limit is 1OOpg of oxygen and the selectivity is 107.4-5 The Fourier- transform infrared (FTIR) detector measures the absorption of IR energy by specific functional groups on the GC analyte.For oxygenated compounds the C-0 stretching region is monitored. Oxygen selectivities of the FTIR method ranged from 4 to > 1000. The selectivity is low presumably owing to broad overlapping gas-phase IR absorption bands.6 The microwave-induced plasma (MIP) detector for GC has many of the characteristics of an ideal oxygen-selective detec- tor. Microwave-induced plasmas atomize the analyte and excite the constituent atoms producing atomic emission characteristic of the compounds eluting from the GC column. Under these conditions the resolution of the column no longer limits the analysis of gasoline samples since non-oxygenated compounds are discriminated against.Furthermore large sample through- put is possible as is the capability of multi-element characteriz- ation of individual gasoline components. The helium MIP is well suited for GC applications because of its efficient excitation of non-metals low power requirements and applicability to vapour-phase samples. The TMolo (Beenakker) cavity developed in 1976 maximizes electric field strength at the center of the cavity (the position of the torch) and makes possible atmospheric-pressure plasmas with rela- tively low power level^.^ The tangential-flow torch for the MIP first described by Bollo-Kamara and Codding uses screw threads imbedded in the torch to direct plasma support gas in a tangential flow within the plasma region.The torch helps produce a self-centered plasma that is capable of handling large amounts of The tangential-flow torch is particularly useful because its tolerance for large solvent loads and lack of plasma-wall contact minimize interferences. A crucial factor in the selective determination of oxygenated compounds by GC-MIP is the reduction of air and water impurities in the helium plasma gas. Minute quantities of air and water produce an oxygen background emission signal that can decrease oxygen selectivity as well as sensitivity. Several researchers have observed negative GC-MIP peaks at the oxygen atomic emission line both for non-oxygenated as well as for some oxygenated corn pound^.'^-^^ These negative peaks are a reduction of the oxygen background most likely owing to molecular recombinations of contaminant oxygen with carbon or hydrogen from the analyte.Addition of hydrogen scavenger gas to the plasma somewhat reduced the extent of negative peaks. However hydrogen addition also reduced oxygen peak intensity.74 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 Several researchers have used oxygen-selective detectors for the analysis of oxygenated compounds in gasoline. Early GC-MIP analyses of oxygenates in gasoline used capillary helium plasmas with hydrogen reagent gas to yield detection limits of 0.25-5 ng s-' of oxygen and selectivities of 10-1000 versus carbon."-'3 Goode and Kimbrough14 observed molecu- lar OH emission in a tangential-flow argon plasma without the addition of reagent gas and reported an oxygen detection limit of 1 ng s-' and selectivity of 800 1.Quimby and c ~ - w o r k e r s ~ ~ - ~ ~ demonstrated that detection limits and selec- tivities for oxygen could be improved with a commercially available instrument that included a water-cooled capillary torch multi-point background correction and a methane- hydrogen-nitrogen reagent gas mixture. The detection limit for oxygen was 0.05 ng s-l with a selectivity of 30000 1. The development of a method for the selective determination of oxygen compounds in gasoline using GC-MIP is described in the present study. In this application a helium MIP is sustained in a tangential-flow torch without the addition of reagent gas. Solvent venting is not necessary since the plasma is stable even during elution of solvent peaks.Analytical figures of merit are presented along with recoveries for spiked samples and results of analyses of alcohols in National Institute of Standards and Technology reference fuel using the proposed GC-MIP method. Results for the analysis of gasoline samples from Greensboro NC USA a Clean Air Act non-attainment area and Columbia SC USA are also presented to further illustrate the suitability of the GC-MIP method for oxygen- selective determinations. Experimental Instrumentation The GC-MIP system utilized a capillary-column gas chroma- tograph modified so that the column could be interfaced with the MIP detector. The column was placed within a few millimeters of the discharge region in the torch and a heated transfer line was placed between the gas chromatograph and the MIP to prevent analyte from condensing.A laboratory- built quartz tangential flow torchg was centered inside the TM, cavity and 2450 MHz microwave energy was launched into the cavity with a variable coupling 100p.l~ The cavity was tuned by varying the position of the loop as well as the position of a screw imbedded in the face of the cavity. The microwave generator was coupled to the cavity by coaxial cable and operated at 120 W forward power with no detectable reflected power ( ~ 0 . 5 W). Ignition of the plasma was accomplished by inserting a wire into the torch with power on and helium flowing. Optical emission from the plasma was viewed axially and laterally (see Fig.1) by a Czerny-Turner monochromator and detected by an R928 photomultiplier. The plasma image was focused onto the entrance slit with a quartz lens which was mounted on an X Y translational stage to allow selection of the plasma viewing region (in lateral mode). The optimal viewing region gas flow rate and microwave power for oxygen-selective detection was previously determined by simplex optimization to be 1.7 mm above the torch threads for lateral viewing 3.12 1 min-l helium and 120 W.19 The torch Tangential flow torch Plasma Column Axial position Support gas - 0 1 2 3 4 5 Lateral position /mm Fig. 1 Axial and lateral viewing positions in the plasma was much shorter in length in the axial viewing arrangement in order to accommodate viewing geometries.As a result helium purge gas was directed across the end of the torch to eliminate back-diffusion of air. The instrumental components of this system are summarized in Table 1. Reagents The plasma support gas was purified extensively on-line using a heated titanium sponge (Aldrich Milwaukee WI USA) confined in a laboratory built stainless-steel cartridge at 550 "C and a large diameter coil of tubing immersed in a dry ice- propan-2-01 (isopropanol) slush (- 60 "C). The MIP helium flow was regulated and metered by an electronic mass flow controller (Porter Instrument Company Hatfield PA USA). A quaternary oxygenated stock solution was prepared from the analytical-reagent grade solvents methanol ethanol 2-methylpropan-2-01 (tert-butanol) and TBME. Oxygen con- centrations were 6.99 6.51 6.97 and 6.37% m/m respectively.An internal standard solution of 2-methylbutan-2-01 ( tert-amyl alcohol) was prepared in 2,2,4-trimethylpentane (iso-octane) such that the oxygen concentration was 2.25% m/m oxygen. Working standards in the concentration range 200 ppm-5.7% m/m oxygen were prepared by serial dilution of the stock solution with the internal standard solution. Procedure Atomic oxygen emission was observed at 777.3 nm. The volume injected was 0.2 pl; all injections were performed by the HP7672 autosampler (Hewlett-Packard Wilmington DE USA). The internal standard was used to correct peak heights and areas for injection-to-injection variations. Detection limits defined as the mass of oxygen that produces a signal three times the standard deviation of the background were evaluated in both axial and lateral modes.Selectivity was evaluated in lateral and axial modes by injecting a series of oxygenated standards (in 2,2,4-trimethylpentane). The oxygen selectivity was the slope of the calibration curve divided by the slope of the non- specific response due to 2,2,4-trimethylpentane at the oxygen emission line. Measurements of peak heights were used to evaluate detection limit and selectivity. An internal standard was added to gasoline samples collected from Columbia SC USA and Greensboro NC USA and NIST Standard Reference Material (SRM) 1829 Alcohols in Reference Fuel. The samples were analysed by GC-MIP and the concentrations of the oxygenated compounds were deter- mined from calibration curves generated from working stan- dards.Spikes of oxygen-containing species were prepared by mixing appropriate amounts of sample with a standard oxygen- containing solution. Peak areas were used for quantification of samples and spikes. Results and Discussion Instrumental Observations The selectivity for oxygen improved under conditions in which oxygen was most efficiently removed from the helium plasma gas accomplished by passing helium through heated titanium sponge followed by a dry ice-propan-2-01 trap. Solvent venting was not required since the plasma was stable even when large amounts of the hydrocarbon solvent were eluted. Since minimal interferences were observed at conditions of optimum oxygen selectivity reagent gases were not necessary. Also the tangen- tial-flow plasma was well-centered in the torch and did not appear to make contact with the torch wall even when the solvent eluted.The absence of atomic or molecular silicon emission signals further verified this supposition.JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 75 Table 1 Instrumentation and operating conditions Chromatogruphy- GC Controller Column Injector MIP interface Carrier gas Gas purifiers Injector temperature Column temperature profile Spectroscopy- Microwave (MW) cavity Cavity diameter Cavity depth MW coupling MW generator Torch Torch i.d. Torch 0.d. Support gas Gas purifiers Optics Image translation Monochromator Slit-width Detector Photomultiplier (PMT) voltage Current amplifier Hewlett-Packard (Wilmington DE USA) 5880 Level 4 J&W Scientific (Folsom CA USA) 30 m DB-1 0.53 mm i.d.Cup splitter Heated transfer line column inserted directly up to plasma edge He at 3.5 ml min-' Disposable oxygen trap (Baxter Scientific Charlotte NC USA) 225 "C 50°C (hold 1 min) ramp to 85 "C at 15°C min-' hold until run terminated (at 5.3 min) Aluminium Beenakker TMolo cavity (laboratory built) 8.9 cm 1.2 cm Shorted movable copper loop Kiva Instruments (Rockville MD USA) 2450 MHz Quartz tangential flow laboratory built 6 mm 8 mm Helium 99.999% Sunox (Columbia SC USA) Ti sponge (Aldrich Milwaukee WI USA) 550 "C dry ice - propan-2-01 trap - 60 "C Quartz 2 in focal length 1.5 in diameter lens X Y translational stage GCA/McPherson Instruments (Acton MA USA) EU-700 sc%nning monochromator with controller 350 mm focal length 1180 lines mm-' grating 20 A mm-' reciprocal linear dispersion variable slit-width 125 pm GCA/McPherson PMT Module EU-701-30 with Hamamatsu R928 PMT (Bridgewater NJ USA) 700 V Keithley Instruments (Cleveland OH USA) Model 427 30 ms rise time Calibration Plots Multi-component mixtures of oxygenated compounds in 2,2,4-trimethylpentane were analysed by the GC-MIP system.A typical chromatogram for the mixture of oxygenated com- pounds is shown in Fig. 2. All chromatograms shown have not been corrected for background or manipulated in any way. Calibration plots of mass of oxygen uersus peak area are shown in Fig. 3 for both axial and lateral viewing of the plasma. Calibrations were done using methanol ethanol 2-methylpropan-2-01 and TBME with 2-methylbutan-2-01 as the internal standard.The linear range of the detector extends up to at least 5-10% oxygen in the injected sample. Sensitivities of the analytical procedure were calculated from the peak area calibration data. The average observed sensitivity for oxygen in the axial mode was 761 area counts per nanogram of oxygen. Lateral oxygen sensitivity was 68 area counts per nanogram of oxygen. This difference is most likely due to the increased viewing volume when axial observation is used. Some differences in oxygen sensitivity were observed for 40 30 20 10 v) 3 +- 0 0 2 2 3 2 2 Y m 2 1 0 2 4 Time/min Fig. 2 Oxygen-selective chromatogram of standards A water (impurity); B methanol (107 ng of 0); C ethanol (100 ng of 0); 2-methylpropan-2-01; (107 ng of 0); E TBME (98.3 ng of 0); F 2-methylbutan-2-01 (internal standard 125 ng of 0); and G 2,2,4-trimethylpentane (solvent 4.27 pg) 0 100 200 300 400 500 Mass of oxygenlng Fig.3 TBME (a) axial viewing; and (b) lateral viewing Calibration plots of peak area uersus mass of oxygen for individual oxygenated compounds but the significance of these differences is not yet known.Selectivity The ability to detect individual elements in a highly selective manner is crucial for an element-selective chromatographic76 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 detector. Oxygen is probably the most difficult element for which to achieve high selectivity due to background levels of oxygen from entrained air water and gas impurities. Selectivity defined as the ratio of the sensitivities for oxygen and carbon measured at the oxygen line was measured in both the axial and lateral viewing modes. Since the selectivity is a ratio of the sensitivities very slight changes in continuum emission which were observed as the mass of carbon in the plasma increased are not expected to significantly alter the measured selectivity.The oxygen selectivity in the axial mode is 155 1 and that in the lateral mode (at optimum plasma viewing position) is 4850 1. The large difference is due to the ability in lateral viewing to choose regions of high selectivity in the plasma. All quantitative work presented here uses data obtained in the lateral viewing mode because of the enhanced selectivity. Qualitatively the solvent (2,2,4-trimethylpentane) produces very little response at the oxygen atomic emission line as seen in Fig.2. Small peaks were observed especially when large amounts of solvent were injected; the peaks could be positive or negative depending on the efficiency of oxygen removal. When oxygen removal was most efficient positive peaks were observed owing to increases in background continuum emis- sion or increases in excitation efficiencies of residual back- ground oxygen. Negative responses seen when oxygen removal was incomplete were due to a decrease in atomic oxygen because of recombination with hydrogen or carbon from the solvent. Observation of molecular emission from CO + at 219.0nm (the most intense band head for CO') verified that the decrease in oxygen emission correlates with an increase in recombination.When the oxygen removal is efficient the largest influence of the solvent is to increase the continuum so dynamic background correction might be able to increase selectivity even further. Detection Limits Oxygen detection limits were evaluated for both axial and lateral viewing positions. In axial viewing oxygen detection limits were between 1.0 and 2.7 ng s-' and in lateral viewing between 0.23 and 2.6 ng s-l (which is equivalent to 0.033-0.054% oxygen in the injected sample using the proposed system). It is interesting to note that while the sensitivity of B 0 2 4 Ti me/m i n Fig. 4 Oxygen-selective chromatogram of NIST SRM 1829 A water; B methanol; C 2-methylpropan-2-01; D 2-methylbutan-2-01 (internal standard); and E 2,2,4-trimethylpentane (solvent) Table 2 Results of NIST SRM 1829 analyses given in % the axial arrangement was 10 times that of the lateral mode the detection limits are very similar.Since the detection limits are based on signal-to-noise ratios the noise observed with axial viewing must also increase lo-fold again consistent with viewing a larger volume of the plasma. The linear range of the analysis is over approximately 3 orders of magnitude. Analysis of NIST Reference Fuel The GC-MIP was used to analyse NIST SRM 1829 Alcohols in Reference Fuel. Fig. 4 shows an oxygen-selective chromatog- ram of the NIST standard. Results of analysis for the NIST reference material are shown in Table 2. Certified values are within experimental error of the measured concentrations for all three NIST standards.Furthermore the mean experimental values did not vary by more than 3% from the certified value except for trace levels of methanol. Lower split ratios could be used to increase the amount of sample entering the column and would be likely to decrease the uncertainty of the determi- nation. The GC-MIP method has been proven to be an accurate method for the determination of oxygenates in a hydrocarbon matrix. Analysis of Gasoline Samples Several gasoline samples were collected from Columbia SC USA and Greensboro NC USA for oxygen-selective analysis. Greensboro is a Clean Air Act non-attainment area meaning gasoline sold is required to contain 2.7% oxygen during the winter months. Fourteen samples in total were collected from various gas stations in the two cities.The results of the analysis by GC-MIP are shown in Table 3. Results for Columbia gasohol (samples 3 and 4) were within the range of the advertised value (10Y0). Low levels of TBME were found in samples 4 (not quantified) and 5. The presence of TBME in the samples is not surprising as it is often used as a low level additive in premium grades. Greensboro samples all contained oxygen. With the exception of the least expensive gasoline which contained ethanol all the Greensboro samples contained TBME. All samples were within experimental error of the mandated 2.7% oxygen. Examples of carbon and oxygen selective chromatograms of gasoline are shown in Fig. 5. Since the major oxygenated-additives are the only components detected in the oxygen mode the GC parameters were adjusted for maximum sample throughput.The run time was 5 min and was followed by heating for 15 min at 170 "C to remove the high-boiling hydrocarbons from the column prior to the start of the next run. Fig. 6(a) shows the results of a typical 5 min analysis of gasoline for oxygenated compounds. Spike Recoveries Gasoline samples previously discussed were spiked with oxy- genated compounds and analysed by GC-MIP. Recoveries are listed in Table 4. All recoveries were well within acceptable ranges except for the low level spike of gas sample number 5. One explanation for poor recoveries in sample 5 is sample handling. Trace concentrations of water can dramatically decrease the solubility of methanol in solution causing loss by phase separation.20 Also evaporative losses of these volatile solvents can further magnify error at low concentrations. Solution 2 Solution 3 Analyte Solution 1 - Experimental Certified Experimental Certified Experimental Certified - 0.335 0.37 *0.099 Methanol 10.33 10.12-lO.29 - 11.39 11.64k0.52 Ethanol - - - 2-Methylpropan-2-01 6.63 6.45 0.54 - - - - -JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 77 Table 3 Results of oxygen-selective gasoline analysis result in parentheses are percent of oxygen in the sample Sample Gas 1 Gas 2 Gas 3* Gas 4* Gas 5* Gas 6 Gas 7 Gas 8* Gas 9* Gas 10* Gas 11* Gas 12* Gas 13* Gas 14* Sample Origin Columbia SC Columbia SC Columbia SC Columbia SC Columbia SC Columbia SC Columbia SC Greensboro NC Greensboro NC Greensboro NC Greensboro NC Greensboro NC Greensboro NC Greensboro NC Ethanol ND* ND 10.24k0.21 (3.56f0.07) 9.85 & 0.44 (3.43 & 0.1 5) ND ND ND ND ND ND ND ND 7.88 k 0.74 (2.74 f 0.26) ND MTBE ND ND ND Not determined 2.37 (0.43) ND ND 13.79 (2.51) 14.81 (2.70) 15.22 (2.77) 14.66k0.69 (2.67k0.13) 15.21 (2.77) ND 14.21 (2.59) *ND = none detected (<detection limit).(a) J I I I 1 I I I 1 I f 1 I I 0 2 4 Time/min Fig. 6 Examples of rapid oxygen-selective analysis for (a) gas 13; and (b) gas 13 spike A water; B methanol; C ethanol; D 2-methylpropan-2-01; E TBME; F 2-methylbutan-2-01 (internal stan- dard); and G 2,2,4-trimethylpentane (solvent) 1 1 I I 1 I 0 5 10 15 20 Tim e/m i n Fig. 5 Comparison of carbon and oxygen-selective chromatograms for the analysis of gasoline sample No.4 (Columbia SC) (a) carbon response (CN band 388.3 nm); and (b) oxygen response (atomic oxygen line 777.3 nm) A ethanol; B TBME; and C 2-methylbutan-2-01 (internal standard) Another source of error is the high instrumental uncertainty when working at trace levels. However improvements can be made by injecting more sample thereby reducing uncertainty in the peak area at low levels of oxygenated compounds. An example of the analysis of a sample of gasoline spiked with oxygenated compounds spike is shown in Fig. 6(b). The per- formance of the GC-MIP method indicates that it is a reliable method for the analysis of complex gasoline samples. Uncertainty of Analysis Relative standard deviations were calculated from the results of 32 oxygen standards analysed by GC-MIP.Each standard was analysed three times and corrected with an internal standard. The average RSD for the analyses was 5.6%. Multiple gasoline samples analysed had similar uncertainties associated with the results. Possible causes of the uncertainty are the residual background oxygen and pressure effects of the large Table 4 Oxygen-selective gasoline analysis giving amount of oxygen added (YO m/m) and the fraction recovered (Yo) Sample Methanol Ethanol t-Butanol TBME Added Recovered Added Recovered Added Recovered Added Recovered Gas 3 0.724 99 0.673 106 0.720 99 0.659 102 Gas 4 0.721 103 0.670 117 0.718 1 04 0.656 106 Gas 5 0.162 157 0.150 119 - - 0.147 72.1 Gas 11 0.718 102 0.668 92 0.715 96 0.654 105 Gas 13 0.717 97 0.667 108 0.714 99 0.653 9578 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 plasma gas flow rate on the reproducible delivery of nanogram amounts of analyte into the plasma. The high-purity grade helium currently in use will be replaced by ultra-pure grade helium to ascertain the effect of gas purity on uncertainty. Also changes to torch design including lower flow require- ments and a sealed capillary column outlet will be investigated in pursuit of improved precision. The authors acknowledge the US Air Force Laboratory Graduate Fellowship Program for the support of C . L. T. and for financial support of the research. References Unzelman G. H. Oil Gas J. 1991 April 15 44. American Society for Testing and Materials Method 4815-89 in Annual Book of ASTM Standards ASTM Philadelphia PA 1992 05.03 612.Bain S. S. and Wesley D. P. Pittsburgh Conference Atlanta GA USA March 8-12 1993 poster No. 373P. Verga G. R. Sironi A. Schneider W. and Frohne J. C. HRC CC J. High Resolut. Chromatogr. Chromatogr. Commun. 1988 11 248. Di Sanzo F. P. J. Chromatogr. Sci. 1990,28 73. Diehl J. W. Finkbeiner J. W. and Di Sanzo F. P. Anal. Chem. 1992 64 3202. Beenakker C. I. M. Spectrochim. Acta Part B 1976 31 483. Bollo-Kamara A. and Codding E. G. Spectrochim. Acta Part B 1981 36,973. 9 10 11 1 :I 2 13 14 15 16 17 18 19 20 Goode S. R Chambers B. and Buddin N. P. Spectrochim. Acta Part B 1985 40 329. Goode S. R. Chambers B. and Buddin N. P. Appl. Spectrosc. 1983 37 439. Bradley C. and Carnahan J. W. Anal. Chem. 1988,60 858. Slatkavitz K. J. Uden P. J. and Barnes R. M. J. Chromatogr. 1986 355 117. Zeng K. W. Ou Q. Y. Wang G. C. and Lu W. L. Spectrochim. Acta Part B 1985 40 349. Goode S. R. and Kimbrough L. K. J. Anal. At. Spectrom. 1988 3 915. Wylie P. L. and Quimby B. D. HRC CC J . High Resolut. Chromatogr. Chromatogr. Commun. 1989 12 813. Quimby B. D. and Sullivan J. J. Anal. Chem. 1990 62 1027. Quimby B. D. Giarocco V. Sullivan J. J. and McCleary K. A. HRC CC J. High Resolut. Chromatogr. Chromatogr. Commun. 1992 15 705. Rait N. Golightly D. W. and Massoni C. J. Spectrochim. Acta Part B 1984 39 931. Thomas C. L. and Goode S. R. Pittsburgh Conference Atlanta GA USA March 8-12 1993 poster No. 53P in preparation. Certificate of Analysis for National Institute of Standards and Technology Standard Reference Material No. 1829 Alcohols in Reference Fuel March 19 1986 p.2. Paper 3 f04392D Received July 26 1993 Accepted October 21 1993

ISSN:0267-9477    

DOI:10.1039/JA9940900073

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

79 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 Liquid Chromatography-Laser-enhanced Ionization Spectrometry for the Speciation of Organolead Compounds Katherine S. Epler* and Thomas C. O'Haver Department of Chemistry and Biochemistry University of Maryland College Park MD 20742 USA Gregory C. Turk Chemical Science and Technology laboratory National Institute of Standards and Technology Gaithersburg MD 20899 USA Liquid chromatography (LC) and laser-enhanced ionization spectrometry (LEI) have been combined to provide a very sensitive method for the measurement of organolead species. Measurement is possible in environrnen- tal and biological matrices which often contain high levels of easily ionized elements that normally interfere with LEI measurements. However LC is able to resolve the interferents from the analytes and LEI is sensitive enough to counterbalance the increase in detection limits that results from the use of LC.The method has been applied to the determination of organolead compounds in National Institute of Standards and Technology Standard Reference Material 1566a Oyster Tissue. Trace levels of trimethyllead were observed in the Oyster Tissue but concentrations were variable among the samples tested. Keywords Laser-enhanced ionization; liquid chromatography; organolead; speciation Laser-enhanced ionization spectrometry (LEI) is a very sensi- tive atomic spectrometric technique for total metal analysis with limits of detection (LODs) often in the S-100pgml-1 range.I4 In LEI one or two dye lasers are tuned to a wavelength characteristic of an electronic transition of the species of interest.The laser beam(s) are directed into an analytical flame which serves as the atom reservoir. A potential is applied across the electrodes in the flame and as the analyte atoms are photoexcited and collisionally ionized the resultant current is measured across the electrodes. Laser-enhanced ionization spectrometry suffers from interferences that result from the presence of easily ionized elements (EIE) like the alkali and alkaline-earth metals. Thus its application to the analysis of real environmental or biological samples containing high salt concentrations can be hampered. By coupling liquid chromatography (LC) to LEI a complementary effect is observed. The LC can physically resolve analytes from interfer- ing EIE while the high sensitivity of LEI can counterbalance the degradation in detection limits resulting from dilution of the injected sample by the LC mobile phase.Laser-enhanced ionization spectrometry is also a good mode of detection for LC because of the compatibility of the LC flow rate with the sample aspiration rate of the burner and because of the simplicity of the interface; a short length of tubing attaches the LC column to the aspiration port of the burner. The combination of LC-LEI has been applied to the determination of organotin compounds in estuarine sediment5 using ion- exchange separation. The use of LC-LEI for the determination of organolead compounds using a reversed-phase LC separation is described in the present paper. There has been renewed interest in lead compounds because of recent concerns about leaded paints lead in drinking water and lead poisoning.Organoleads were in the spotlight a few years ago because of the use of tetra-alkylleads as octane boosters in gasoline. In 1983 allowed lead concentrations in gasoline were G0.29 g 1-1 for leaded and G0.013 g 1-l for unleaded gasoline in the United States.6 The tetra-alkylleads decompose to form trialkylleads (which are SO-100 times more toxic than inorganic lead) dialkylleads and inorganic lead.6 Frequently gas chromatography (GC) is used for separation in the analysis of organoleads. Radziuk et aL7 have compared LODs for tetra-alkyllead using five GC atomic spectrometric * Current address Organic Analytical Research Division Chemical Science and Technology Laboratory National Institute of Standards and Technology Gaithersburg MD 20899 USA.methods. Using 1-5 pl injections of trimethylethyllead solution they obtained the following absolute LODs GC-flame atomic absorption spectrometry (FAAS) 1.5 ng; GC-atomic fluor- escence 0.3 ng; GC-quartz furnace AAS 0.1 ng; GC-quartz furnace suspended in a flame 0.09 ng; and GC-electrothermal AAS (ETAAS) 0.03 ng7 Gas chromatography methods have been faulted for being unable to determine the trialkylleads due to their instability at temperatures used in GC and their reactivity with the GC The dialkylleads are also thermally unstable' and involati1e.l' It is important to measure the ionic alkylleads since they are degradation products of the tetra-alkylleads. An LC separation does not depend on the volatility of the analytes.Liquid chromatography has been coupled to FAAS,8*11*12 inductively coupled plasma (ICP),13 ICP mass spectrometry (MS)14 and ETAASI5-l7 for the analysis of organoleads. Detection limits range over three orders of magni- tude from 500 ng ml-I for the tetra-alkylleads by LC-FAAS12 to 0.25 ng ml-I for tetraethyllead by LC-1CP-MS.l4 In the experiments described here a reversed-phase LC column was attached to the LEI flame. Four organolead compounds and inorganic lead can be differentiated by LC and sodium can be resolved from the lead species. Sensitive detection by LEI results in LODs comparable to those for LC-ICP-MS and GC-atomic spectrometric techniques. The method was applied to the measurement of organolead com- pounds in a National Institute of Science and Technology Standard Reference Material (SRM) 1566a Oyster Tissue; trimethyllead was found in a few samples that were taken from one bottle.Experimental Laser-enhanced ionization spectrometry Two dye lasers were pumped by a frequency-doubled Nd YAG laser. The first dye laser contained Rhodamine 6G; the beam was frequency-doubled to 283.31 nm which excited the lead atom from the 6p level of the ground state to the 7s level at 35287 cm-' (Fig. 1). The second dye laser containing Rhodamine 610 was tuned to 600.19nm. This beam excited the lead atom from 35287 cm-' to the 8p level at 51944 cm-' 7876 cm-l from the lead ionization limit of 59820 cm-'. From here the lead atom was collisionally ionized.The water-cooled cathode was operated at - 1000 V and an air-acetylene flame was used. The LEI measurements were performed using a80 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 I I 2 "1 2 0- - Fig. 1 Two-step photoexcitation and collisional ionization of lead Model OGS- 1 LEI Burner System (Sopra Bois-Colombes France) which consists of the burner cathode resistor (10 kn) capacitor (100 pF) pre-amplifier and high-voltage source in a radiofrequency shielded box. Optics were aligned to superim- pose the laser beams a few millimeters below the cathode. Data were acquired using a Stanford Research Systems Model SR250 gated integrator and SR245 computer interface. A schematic diagram of the set-up is shown in Fig.2. Liquid chromatography The organolead compounds were separated on a Zorbax ODS reversed-phase column using an LKB 2150 pump with a Rheodyne 7125 injector and a 20 pl sample loop. The method is an adaptation of that of MacCrehan and Durst,l8 using an isocratic mixture of methanol water and ammonium acetate. Various solvent strengths were studied. A mixture of meth- anol-water (9 + 1 ) containing 0.01 mol 1-1 ammonium acetate was determined to give the best separation of triethyl- trimethyl- tetramethyl- and tetraethyl-lead. The eluent flow rate was 1 ml min-' and the aspiration rate of the flame without connection to the LC was 8.6 ml min-'. Sample Preparation Two sample preparation procedures were studied for the analysis of Oyster Tissue an extraction and a digestion.The extraction method was similar to the one that had previously been successful for rapidly extracting organotin compounds from ~ediment.~ A 0.5 g portion of freeze-dried powdered Oyster Tissue (SRM 1566a) 3 ml of a mixture of hexanes and 3 ml of a 0.5 moll-' solution of chelating agent were placed in centrifuge tubes in an ultrasonicating bath for 60 min. The use of chelating agents is frequently reported in the literature on ~rganolead."-~~ Sodium diethyldithiocarbamate (NaDDC) and ammonium pyrrolidin-l-yldithioformate [ammonium pyr- rolidine dithiocarbanate (APDC)] were investigated in the present work. After ultrasonication samples were centrifuged and the supernatants were removed and filtered through 50 pm syringe filters. Using each chelating agent both spiked and unspiked samples were extracted.A spiked sample was pre- pared by adding 100 pg ml-' of lead as each of tetramethyllead trimethyllead tetraethyllead and triethyllead in methanol- water (7 + 3) to an Oyster Tissue sample prior to extraction. Both spiked and unspiked pairs of samples were placed in the refrigerator (40°C) overnight so that the Oyster Tissue could potentially absorb the spikes. The digestion method was an adaptation of the procedure of Chau et a1.19 Oyster Tissue samples (0.5 g) were digested in 5 ml of 20% m/v tetramethylammonium hydroxide (TMAH) overnight at room temperature. The pH was then adjusted to 8 by the addition of 50% v/v 12 mol 1-1 hydrochloric acid. A 3 ml aliquot of 0.5 moll-' NaDDC solution 3 ml of toluene and 2 g of sodium chloride (to increase the solubility of the trialkylleads in the toluene) were added and the mixture was shaken by hand for 20 min.The mixture was then centrifuged to separate the phases. The toluene phase was removed and was filtered through a 0.50 pm syringe filter. Spiked and unspiked samples were digested. Approximately 100 pg ml- of each of the four organolead compounds were spiked into the Oyster Tissue prior to digestion Results and Discussion An eluent of methanol-water (9 + 1) containing 0.01 mol 1-1 of ammonium acetate resulted in good separation of the organolead species (Fig. 3). Liquid-chromatography-LEI has an LOD for tetraethyllead of 0.9 ng ml-I or 20 pg of lead for a 20 pl injection using a 1 s time constant. The LOD is calculated from the data shown in Fig.4 the chromatogram of a 20ngml-l solution of lead as tetraethyllead in hexanes.This LOD is the concentration that would give a signal equal to three times the root mean square chromatographic baseline noise and is comparable to LODs of 0.05 ng ml-' obtained by GC-ETAAS21,22 (25 pg absolute)21 and 0.25 ng ml-' (25 pg absolute) by LC-ICP-MS.14 The LODs for LC-ICP-MS and GC-ETAAS obtained in refs. 14 and 21 respectively were also calculated as three times the standard deviation of the baseline noise divided by the slope of the calibration curve; the method used for calculating the LOD for GC-ETAAS in ref. 22 was not stated. The lowest LOD reported in the literature is 0.18 pg ml-I for a unique method in which tri- and di-methyllead are ethylated by sodium tetraethylborate the ethylated compounds trapped and then thermally desorbed and flushed into a quartz furnace where atomic absorption is measured." This detection limit is orders of magnitude lower Trigger High voltage Frequency doubler I Oscilloscope 1- Amplifier I Gated integrator Computer Fig.2 Schematic dia.gram of the instrumentJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL. 9 81 800 TE L I L I I I I 1 I 0 5 10 15 20 25 30 Tim e/m in Fig.3 Chromatogram of LC separation of four organolead com- pounds equivalent to 500 ng ml-' of lead each in 70% methanol- 30% water. TriEL = triethyllead; TriML= trimethyllead; TML = tetra- methyllead; TEL = tetraethyllead. The eluent is 9 + 1 methanol-water containing 0.01 moll-' ammonium acetate and is pumped at 1 ml min- '.Sample size = 20 p1 '0° I 600 500 2 400 3 m .- 300 v) 200 100 0' I I I I 20 22 24 26 28 Time/m i n Fig. 4 Chromatogram showing 20 ng ml-' of lead as TEL in hexanes using chromatographic conditions described in Fig. 3. Detection limit is 0.9 ng ml-' of lead or 20 pg absolute for a 20 pl injection than anything else reported; unfortunately it is applicable only to the measurement of tri- and di-methyllead. Analysis of Oyster Tissue Because oysters live in waters where organolead pollution from gasoline-powered boat engines is possible SRM 1566a seemed a likely matrix in which to find organolead compounds. When the oyster tissue was extracted using hexane chromato- grams using both NaDDC and APDC as the chelating agents showed barely detectable tetraethyllead peaks.The NaDDC extract also appeared to contain a small amount of triethyllead. Both chromatograms showed large concentrations of sodium and inorganic lead. Using the hexane extraction method 100pgml-' spikes of the organoleads were recovered at a level of only about 0.5%. When the Oyster Tissue was digested in TMAH inorganic lead and trimethyllead peaks were clearly observed in several unspiked samples (Fig. 5) but a high degree of variation between samples was observed as is shown in Table 1. Recoveries of organolead from one spiked sample were as follows triethyllead 48%; trimethyllead 45%; tetramethyllead 24%; and tetraethyllead 48%. Although these recovery data result from the digestion of only one spiked sample a 45% recovery implies that the actual trimethyllead concentration in some of the Oyster Tissue samples may have been closer to 3 ng g-' of lead as trimethyllead.No organoleads were detected in a second bottle of Oyster Tissue. The variability in 0.24 0.16 \ 2 - ln C 0) .- * 0.08 0' I I I I 2 4 6 8 10 Ti me/mi n Fig. 5 Chromatogram for the separation of inorganic lead and TriML in oyster tissue by LC. Chromatographic conditions are described in Fig. 3 Table 1 Organolead concentrations in five oyster tissue samples Sample No. 1 2 3 4 5 ~~~ - ~~ Concentration/ng g- ' 1.34 1.23 3.04 1.49 0.49 organolead concentration in different bottles of Oyster Tissue might have resulted from inhomogeneity or from differences in storage i.e. whether one bottle was exposed to more light or higher temperatures than another.Variability within a bottle could arise from the particular location of the sample in the bottle i.e. a sample at the top of the bottle could be exposed to more light and air than a sample from the centre of the bottle where it would be surrounded by Oyster Tissue. The bottles were not mixed before the samples were removed. This SRM is certified only for the total concentration of lead (0.371 mg kg-l) and there is no information regarding the speciation of lead. The absence of tetra-alkylleads in these samples is not entirely unexpected; the tetra-alkylleads are not only fairly volatile but also decompose rather rapidly when exposed to sunlight. The half-life of tetramethyllead in the atmosphere is 10 h in summer and 34 h in winter; the half-life of tetraethyllead is 2 h in summer and 8 h in winter.6 The trialkylleads that are formed are converted into dialkylleads which are then de-alkylated to form inorganic lead.The use of tetraalkylleads as anti-knock agents relies on the ease with which they can be oxidized to form lead oxide. All samples tested showed large inorganic lead peaks and in many cases little organic lead. It is obvious that both sample preparation procedures used in this study were inadequate. Further work is necessary to determine whether irreproducible levels of trimethyllead in the Oyster Tissue were a result of inhomogeneity or the fault of the sample preparation method or of the analyst. At the very least the method of sample preparation needs to be improved to increase spike recoveries.However while the Oyster Tissue experiments were not entirely successful they do demonstrate the applicability of LC-LEI to the analysis of very low levels of organolead species in a real sample. This work was included in the dissertation of K.S.E. which was submitted in partial fulfillment of the requirements for the Ph.D. degree from the University of Maryland. Certain com- mercial equipment instruments or materials are identified in this report to specify adequately the experimental procedure. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology nor does it imply that the materials or equipment identified are necessarily the best available for the purpose.82 JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY FEBRUARY 1994 VOL.9 References 1 Turk G. C. J. Anal. At. Spectrom. 1987 2 573. 2 Travis J. C. Turk G. C. and Green R. B. Anal. Chem. 1982 54 1006A. 3 Turk G. C. Travis J. C. and DeVoe J. R. J. Phys. 1983 C7 301. 4 Turk G. C. Anal. Chem. 1981 53 1187. 5 Epler K. S. O’Haver T. C. Turk G. C. and MacCrehan W. A. Anal. Chem. 1988 60 2062. 6 Organometallic Compounds In the Environment ed. Craig P. J. Wiley New York 1986. 7 Radziuk B. Thomassen Y. Butler L. R. P. Van Loon J. C. and Chau Y. K. Anal. Chim. Acta 1979 108 31. 8 Robinson J. W. and Boothe E. D. Spectrosc. Lett. 1984,17,689. 9 Estes S. A. Uden P. C. and Barnes R. M. Anal. Chem. 1982 54 2402. 10 Rapsomanikis S. Donard 0. F. X. and Weber J. H. Anal Chem. 1986,58 35. 11 Botre C. Cacace F.and Cozzani R. Anal. Lett. 1976 9 825. 12 Messman J. D. and Rains T. C. Anal. Chem. 1981 53 1632. 13 Ibrahim M. Gilbert T. W. and Caruso J. A. J . Chromatogr. Sci. 1984 22 111. 14 Al-Rashdan A. Heitkemper D. and Caruso J. A. J. Chromatogr. Sci. 1991 29 98. 11 5 16 17 18 19 20 21 22 Orren D. K. Caldwell-Kenkel J. C. and Mushak P. J. Anal. Toxicol. 1985 9 258. Koizumi H. McLaughlin R. D. and Hadeishi T. Anal. Chem. 1979 51 387. Vickrey R. M. Howell H. E. Harrison G. V. and Ramelow G. J. Anal. Chem. 1980 52 1743. MacCrehan W. A. and Durst R. A. Assessing the Environmental Impact of Fossil-Fuel Based Energy Sources Measurement of Organometal Species in Biological and Water Samples Using Liquid Chromatography with Electrochemical Detection EPA- 600/7-79-211 EPA Washington DC. Chau Y. K. Wong P. T. S. Bengert G. A. and Dunn J. L. Anal. Chem. 1984 56 271. Nygren 0. andNilsson C.-A. J . Anal. At. Spectrom. 1987,2 805. Harrison R. M. and Radojevic M. Enuiron. Technol. Lett. 1985 6 129. Cruz R. B. Lorouso C. George S. Thomassen Y. Kinrade J. D. Butler L. R. P. Lye J. and Van Loon J. C. Spectrochim. Acta Part B 1980 35 775. Paper 3/06262G Received September 30 1993 Accepted October 19 1993

ISSN:0267-9477    

DOI:10.1039/JA9940900079

出版商:RSC    

年代:1994

数据来源: RSC