Journal of Analytical Atomic Spectrometry (Including Atomic Spectrometry Updates) JAAS Editorial Board* Chairman B. L. Sharp (Loughborough UK) J. M. Gordon (Cambridge UK) S. J. Haswell (Hull UK) S. J. Hill (Plymouth UK) R. C. Hutton (Winsford UK) D. Littlejohn (Glasgow UK) J. Marshall (Middlesbrough UK) D. L. Miles (Keyworth UK) A. Sanz-Medel (Oviedo Spain) *The JAAS Editorial Board reports to the Analytical Editorial Board Chairman J. N. Miller (Loughborough UK) JAAS Advisory Board F. C. Adams (Antwerp Belgium) R. M. Barnes (Amherst MA USA) L. Bezur (Budapest Hungary) M. W. Blades (Vancouver Canada) R. F. Browner (Atlanta GA USA) S. Caroli (Rome Italy) A. J. Curtius (Floriandpolis Brazil) J. B. Dawson (Leeds UK) M. T. C. de Loos-Vollebregt (Delft The Netherlands) L. Ebdon (Plymouth UK) M.S. Epstein (Gaithersburg MD USA) Fang Zhao-lun (Shenyang China) W. Frech (UmeA Sweden) A. L. Gray (Egham UK) S. Greenfield (Loughborough UK) G. M. Hieftje (Bloomington IN USA) B. V. L'vov (St. Petersburg Russia) R. K. Marcus (Clemson SC USA) J. M. Mermet (Villeurbanne France) T. Nakahara (Osaka Japan) Ni Zhe-ming (Beijing China) N. Omenetto (lspra Italy) C. J. Park (Taejon Korea) R. E. Sturgeon (Ottawa Canada) V. Sychra (Prague Czech Republic) R. Van Grieken (Antwerp Belgium) A. Walsh .K. B. (Victona Australia) B. Welz (Uberlingen Germany) Atomic Spectrometry Updates Editorial Board Chairman *D. L. Miles (Keyworth UK) J. Armstrong (Edinburgh UK) J. R. Bacon (Aberdeen UK) C. Barnard (Glasgow UK) R. M. Barnes (Amherst MA USA) S. Branch (High Wycombe UK) R.Bye (Oslo Norway) J. Carroll (Middlesbrough UK) M. R. Cave (Keyworth UK) S. Chenery (Keyworth UK) *J. M. Cook (Keyworth UK) *M. S. Cresser (Aberdeen UK) H. M. Crews (Norwich UK) J. S. Crighton (Sunbury-on-Thames UK) *J. B. Dawson (Leeds UK) J. R. Dean (Newcastle upon Tyne UK) *A. T. Ellis (Oxford UK) *E. H. Evans (Plymouth UK) J. Fazakas (Budapest Hungary) A. Fisher (Plymouth UK) *J. M. Gordon (Cambridge UK) D. J. Halls (Glasgow UK) *S. J. Hill (Plymouth UK) K. W. Jackson (Albany NY USA) R. Jowitt (Middlesbrough UK) K. Kitagawa (Nagoya Japan) J. Kubova (Bratislava Slovak Republic) *J. Marshall (Middlesbrough U K ) H. Matusiewicz (Poznan Poland) A. W. McMahon (Manchester UK) J. M. Mermet (Villeurbanne France) R. G. Michel (Storrs CT USA) T. Nakahara (Osaka Japan) Ni Zhe-ming (Beijing China) P.R. Poole (Hamilton New Zealand) P. J. Potts (Milton Keynes UK) W. J. Price (Budleigh Salterton UK) C. J. Rademeyer (Pretoria South Africa) *M. H. Ramsey (London UK) P. G. Riby (Greenwich UK) A. Sanz-Medel (Oviedo Spain) 'B. L. Sharp (Loughborough UK) I. L. Shuttler (Uberlingen Germany) S. T. Sparkes (Plymouth UK) R. Stephens (Halifax Canada) J. Stupar (Ljubljana Slovenia) R. E. Sturgeon (Ottawa Canada) *A. Taylor (Guildford UK) G. C. Turk (Gaithersburg MD USA) J. F. Tyson (Amherst MA USA) P. Watkins (London UK) B. Welz (Uberlingen Germany) J. Williams (Egham UK) J. B. Willis (Victoria Australia) *Members of the ASU Executive Committee Editor JAAS Janice M. Gordon The Royal Society of Chemistry Thomas Graham House Science Park Milton Road Cambridge CB4 4WF UK.Telephone + 44 (0) 1223 420066. Fax + 44 (0) 1223 420247. E-mail RSC1 @RSC.ORG (Internet) Senior Assistant Editor Brenda Holliday Editorial Secretary Lesley Turney US Associate Editor JAAS Dr. J. M. Harnly US Department of Agriculture Beltsville Human Nutrition Research Center Beltsville MD 20705 USA. Telephone 301 -504-8569 Assistant Editor Ziva Whitelock Advertisements Advertisement Department The Royal Society of Chemistry Burlington House Piccadilly London W1 V OBN UK. Telephone + 44 (0) 171 -287 3091. Fax + 44 (0) 171 -494 11 34. Information for Authors Full details of how to submit materials for publi- cation in JAAS are given in the Instructions to Authors in Issue 1. Separate copies are available on request. The Journal of Analytical Atomic Spectrometry (JAAS) is an international journal for the publi- cation of original research papers communi- cations and letters concerned with the development and analytical application of atomic spectrometric techniques.The journal is pub- lished twelve times a year including comprehen- sive reviews of specific topics of interest to practising atomic spectroscopists and incorpor- ates the literature reviews which were previously published in Annual Reports on Analytical Atomic Spectroscopy (ARAAS). Manuscripts intended for publication must describe original work related to atomic spectro- metric analysis. Papers on all aspects of the sub- ject will be accepted including fundamental studies novel instrument developments and prac- tical analytical applications.As well as AAS AES and AFS papers will be welcomed on atomic mass spectrometry X-ray fluorescence/emission spectrometry and secondary emission spec- trometry. Papers describing the measurement of molecular species where these relate to the characterization of sources normally used for the production of atoms or are concerned for example with indirect methods of analysis will also be acceptable for publication. Papers describing the development and applications of hybrid techniques (e.g.- GC-coupled AAS and HPLC-ICP) will be particularly welcome. Manuscripts on other subjects of direct interest to atomic spectroscopists including sample prep- aration and dissolution and analyte pre-concen- tration procedures as well as the statistical interpretation and use of atomic spectrometric data will also be acceptable for publication.There is no page charge. The following types of papers will be considered. Full papers describing original work. Communications which must be on an urgent matter and be of obvious scientific importance. Communications receive priority and are usually published within 2-3 months of receipt. They are intended for brief descriptions of work that has progressed to a stage at which it is likely to be valuable to workers faced with similar problems. Reviews which must be a critical evaluation of the existing state of knowledge on a particular facet of analytical spectrometry. Every paper (except Communications) will be submitted to at least two referees by whose advice the Editorial Board of JAAS will be guided as to its acceptance or rejection.Papers that are accepted must not be published elsewhere except by permission. Submission of a manuscript will be regarded as an undertaking that the same material is not being considered for publication by another journal. Manuscripts (three copies typed in double spacing) should be sent to Janice M. Gordon Editor JAAS or Dr. J. M. Harnly US Associate Editor JAAS. All queries relating to the presentation and sub- mission of papers and any correspondence regarding accepted papers and proofs should be directed to the Editor or US Editor (addresses as above). Members of the JAAS Editorial Board (who may be contacted directly or via the Editorial Office) would welcome comments suggestions and advice on general policy matters concerning JAAS.Fifty reprints are supplied free of charge. Journal of Analytical Atomic Spectrometry (JAAS) (ISSN 0267-9477) is published monthly by The Royal Society of Chemistry Thomas Graham House Science Park Milton Road Cambridge CB4 4WF UK. All orders accompanied with payment should be sent directly to The Royal Society of Chemistry Turpin Distribution Services Ltd. Blackhorse Road Letchworth Herts. SG6 lHN UK Tel. +44 (0) 462 672555; Telex 825372 Turpin G; Fax +44 (0) 462 480947. Turpin Distribution Services Ltd. is wholly owned by The Royal Society of Chemistry. 1995 Annual subscription rate EEA €312.00 USA $941.50 Canada f538.00 (+ GST) Rest of World f538.00. Customers should make payments by cheque in sterling payable on a UK clearing bank or in US dollars payable on a US clearing bank. Air freight and mailing in the USA by Publications Expediting Inc.200 Meacham Avenue Elmont NY 11 003. USA Postmaster send address changes to Journal of Analytical Atomic Spectrometry (JAAS) Publications Expediting Inc. 200 Meacham Avenue Elmont NY 11003. Postage paid at Jamaica NY 11431. All other despatches outside the UK by Bulk Airmail within Europe Accelerated Surface Post outside Europe. PRINTED IN THE UK. @The Royal Society of Chemistry 1995. All rights reserved. No part of this publication may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photographic recording or otherwise without the prior permission of the publishers.Journal of Analytical Atomic Spectrometry (Including Atomic Spectrometry Updates) JAAS Editorial Board* Chairman B.L. Sharp (Loughborough UK) J. M. Gordon (Cambridge UK) S. J. Haswell (Hull UK) S. J. Hill (Plymouth UK) R. C. Hutton (Winsford UK) D. Littlejohn (Glasgow UK) J. Marshall (Middlesbrough UK) D. L. Miles (Keyworth UK) A. Sanz-Medel (Oviedo Spain) JAAS Advisory Board F. C. Adams (Antwerp Belgium) R. M. Barnes (Amherst MA USA) L. Bezur (Budapest Hungary) M. W. Blades (Vancouver Canada) R. F. Browner (Atlanta GA USA) S. Caroli (Rome Italy) A. J. Curtius (Norianopolis Brazil) J. B. Dawson (Leeds UK) M. T. C. de Loos-Vollebregt (Delft The Nether L. Ebdon (Plymouth UK) M. S. Epstein (Gaithersburg MD USA) Fang Zhao-lun (Shenyang China) W. Frech (Urnei Sweden) A. L.Gray (Egham UK) S. Greenfield (Loughborough UK) G. M. Hieftje (Bloomington IN USA) B. V. L'vov (St. Petersburg Russia) R. K. Marcus (Clemson SC USA) J. M. Mermet (Villeurbanne France) T. Nakahara (Osaka Japan) Ni Zhe-ming (Beijing China) N. Omenetto (lspra Italy) C. J. Park (Taejon Korea) R. E. Sturgeon (Ottawa Canada) V. Sychra (Prague Czech Republic) R. Van Grieken (Antwerp Belgium) A. Walsh ,K. 6. (Victoria Australia) B. Welz (Uberlingen Germany) ids) Atomic Spectrometry Updates Editorial Board Chairman *D. L. Miles (Keyworth UK) J. Armstrong (Edinburgh UK) J. R. Bacon (Aberdeen UK) C. Barnard (Glasgow UK) R. M. Barnes (Amherst MA USA) S. Branch (High Wycombe U K ) R. Bye (Oslo Norway) J. Carroll (Middlesbrough UK) M. R. Cave (Keyworth UK) S. Chenery (Keyworth UK) *J.M. Cook (Keyworth UK) 'M. S. Cresser (Aberdeen UK) H. M. Crews (Norwich UK) J. S. Crighton (Sunbury-on-Thames UK *J. €3. Dawson (Leeds UK) J. R. Dean (Newcastle upon Tyne UK) *A. T. Ellis (Oxford UK) *E. H. Evans (Plymouth UK) J. Fazakas (Budapest Hungary) A. Fisher (Plymouth UK) 'J. M. Gordon (Cambridge UK) D. J. Halls (Glasgow UK) *S. J. Hill (Plymouth UK) K. W. Jackson (Albany NY USA) R. Jowi t t (Middlesbrough UK ) K. Kitagawa (Nagoya Japan) J. Kubova (Bratislava Slovak Republic) *J. Marshall (Middlesbrough UK) H. Matusiewicz (Poznan Poland) A. W. McMahon (Manchester UK) J. M. Mermet (Villeurbanne France) R. G. Michel (Storrs CT USA) T. Nakahara (Osaka Japan) Ni Zhe-ming (Beijing China) P. R. Poole (Hamilton New Zealand) P. J. Potts (Milton Keynes UK) W.J. Price (Budleigh Salterton UK) C. J. Rademeyer (Pretoria South Africa) *M. H. Ramsey (London UK) P. G. Riby (Greenwich UK) A. Sanz-Medel (Oviedo Spain) *B. L. Sharp (Loughborough UK) I. L. Shuttler (Uberlingen Germany) S. T. Sparkes (Plymouth UK) R. Stephens (Halifax Canada) J. Stupar (Ljubljana Slovenia) R. E. Sturgeon (Ottawa Canada) *A. Taylor (Guildford UK) G. C. Turk (Gaithersburg MD USA) J. F. Tyson (Amherst MA USA) P. Watkins (London UK) 6. Welz (Uberlingen Germany) J. Williams (Egham UK) J. 8. Willis (Victoria Australia) *Members of the ASU Executive Committee Editor JAAS Janice M. Gordon The Royal Society of Chemistry Thomas Graham House Science Park Milton Road Cambridge CB4 4WF UK. Telephone + 44 (0) 1223 420066. Fax + 44 (0) 1223 420247. E-mail RSCl @RSC.ORG (Internet) Senior Assistant Editor Brenda Holliday Editorial Secretary Lesley Turney US Associate Editor JAAS Dr.J. M. Harnly US Department of Agriculture Beltsville Human Nutrition Research Center Beltsville MD 20705 USA.. Telephone 301 -504-8569 Assistant Editor Ziva Whitelock Advertisements Advertisement Department The Royal SQciety of Chemistry Burlington House Piccadilly London W1 V OBN UK. Telephone + 44 (0) 171 -287 3091. Fax -1 44 (0) 171 -494 11 34. Information for Authors Full details of how to submit materials for publi- cation in JAAS are given in the Instructions to Authors in Issue 1. Separate copies are available on request. The Journal of Analytical Atomic Spectrometry (JAAS) is an international journal for the publi- cation of original research papers communi- cations and letters concerned with the development and analytical application of atomic spectrometric techniques.The journal is pub- lished twelve times a year including comprehen- sive reviews of specific topics of interest to practising atomic spectroscopists and incorpor- ates the literature reviews which were previously published in Annual Reports on Analytical Atomic Spectroscopy (ARMS). Manuscripts intended for publication must describe original work related to atomic spectro- metric analysis. Papers on all aspects of the sub- ject will be accepted including fundamental studies novel instrument developments and prac- tical analytical applications. As well as AAS AES and AFS papers will be welcomed on atomic mass spectrometry X-ray fluorescence/emission spectrometry and secondary emission spec- trometry.Papers describing the measurement of molecular species where these relate to the characterization of sources normally used for the production of atoms or are concerned for example with indirect methods of analysis will also be acceptable for publication. Papers describing the development and applications of hybrid techniques (e.g. GC-coupled AAS and HPLC-ICP) will be particularly welcome. Manuscripts on other subjects of direct interest to atomic spectroscopists including sample prep- aration and dissolution and analyte pre-concen- tration procedures as well as the statistical interpretation and use of atomic spectrometric data will also be acceptable for publication. There is no page charge.The following types of papers will be considered. f u l l papers describing original work. Communications which must be on an urgent matter and be of obvious scientific importance. Communications receive priority and are usually published within 2-3 months of receipt. They are intended for brief descriptions of work that has progressed to a stage at which it is likely to be valuable to workers faced with similar problems. Reviews which must be a critical evaluation of the existing state of knowledge on a particular facet of analytical spectrometry. Every paper (except Communications) will be submitted to at least two referees by whose advice the Editorial Board of JAAS will be guided as to its acceptance or rejection. Papers that are accepted must not be published elsewhere except by permission.Submission of a manuscript will be regarded as an undertaking that the same material is not being considered for publication by another journal. Manuscripts (three copies typed in double spacing) should be sent to Janice M. Gordon Editor JAAS or Dr. J. M. Harnly US Associate Editor JAAS. All queries relating to the presentation and sub- mission of papers and any correspondence regarding accepted papers and proofs should be directed to the Editor or US Editor (addresses as above). Members of the JAAS Editorial Board (who may be contacted directly or via the Editorial Office) would welcome comments suggestions and advice on general policy matters concerning JAAS. Fifty reprints are supplied free of charge. Journal of Analytical Atomic Spectrometry (JAAS) (ISSN 0267-9477) is published monthly by The Royal Society of Chemistry Thomas Graham House Science Park Milton Road Cambridge CB4 4WF UK.All orders accompanied with payment should be sent directly to The Royal Society of Chemistry Turpin Distribution Services Ltd. Blackhorse Road Letchworth Herts. SG6 IHN UK Tel. +44 (0) 1462 672555; Telex 825372 Turpin G; Fax +44 (0) 1462 480947. Turpin Distribution Services Ltd. is wholly owned by The Royal Society of Chemistry. 1995 Annual subscription rate EEA €51 2.00 USA $941 50 Canada f538.00 (+ GST) Rest of World f538.00. Customers should make payments by cheque in sterling payable on a UK clearing bank or in US dollars payable on a US clearing bank. Air freight and mailing in the USA by Publications Expediting Inc. 200 Meacham Avenue Elmont NY 11 003. USA Postmaster send address changes to Journal of Analytical Atomic Spectrometry (JAAS) Publications Expediting Inc. 200 Meacham Avenue Elmont NY 11 003. Postage paid at Jamaica NY 11 431. All other despatches outside the UK by Bulk Airmail within Europe Accelerated Surface Post outside Europe. PRINTED IN THE UK. @The Royal Society of Chemistry 1995. All rights reserved. No part of this publication may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photographic recording or otherwise without the prior permission of the publishers.