"AnalystThe Analytical Journal Of The Royal Society Of ChemistryAssociate Scientific Editors*Chairman: Professor James N. Miller(Department of Chemistry, Loughborough University of Technology, UK)Dr Y ngvar Thomassen (Arbeidsmiljo lnstituttet,Oslo, Norway)Professor Colin S. Creaser (Department ofChemistry and Physics, Nottingham TrentUniversity, UK)Professor Pankaj Vadgama (Department ofMedicine, University of Manchester, UK)Professor Malcolm R. Smyth (Department ofChemical Sciences, Dublin City University, Eire)'All ASEs are also members of the Analytical Editorial Board.US ASSOCIATE EDITOR, Julian F. TysonDepartment of Chemistry, University of Massachusetts, Box 3451 0 Amherst, MA 01 003-451 0, USATelephone: +1 413 545 0195; Fax: +1 413 545 4846; E-mail: TYSON@CHEM.UMASS.EDUAnalytical Editorial BoardChairman: Professor J.N. Miller (Loughborough, UK)M. Cooke (Sheffield, UK)A. G. Davies (London, UK)A. G. Fogg (Loughborough, UK)G. M. Greenway (Hull, UK)S. J. Hill (Plymouth, UK)R. M. Miller (Gouda, The Netherlands)H. S. Minhas (Cambridge, UK)B. L. Sharp (Loughborough, UK)Advisory BoardN. W. Barnett (Victoria, Australia)K. D. Battle (Leeds, UK)A. M. Bond (Victoria, Australia)R. G. Brereton (Bfistol, UK)U. A. Th. Brinkman (Amsterdam, The Netherlands)A. C. Calokerinos (Athens, Greece)P. Camilleri (Harlow, UK)P. R. Coulet (Lyon, France)D. Diamond (Dublin, Eire)L. Ebdon (Plymouth, UK)H. Emons (Julich, Germany)J. P. Foley (Villanova, PA, USA)M. F. Gin6 (Sao Paulo, Brazil)J.D. Glennon (Cork, Eire)L. Gorton (Lund, Sweden)S. J. Haswell (Hull, UK)A. Hulanicki (Warsaw, Poland)S. Lunte (Lawrence, KS, USA)F. Palmisano (Palermo, Italy)J. Pawliszyn (Ontario, Canada)T. B. Pierce (Harwell, UK)J. ROZiCka (Seattle, WA, USA)1. L. Shuttler (Uberlingen, Germany)K. Stulik (Prague, Czech Republic)J. D. R. Thomas (Wrexham, UK)K. C. Thompson (Rotherham, UK)M. Thompson (Toronto, Canada)M. Valcarcel (Cordoba, Spain)C. M. G. van den Berg (Liverpool, UK)J. Wang (Las Cruces, NM, USA)I. D. Wilson (Macclesfield, UK)Publishing Division, AnalyticalManaging Editor, Harpal S. MinhasDeputy Editor, Sarah J. R. Williams Editorial Secretaries: Claire Harris; Frances ThomsonTelephone: +44(0)1223 420066; Fax: +44(0)1223 420247; E-mail: ANALYST@RSC.ORGProduction Division, AnalyticalProduction Manager, Janice M.GordonProduction Editor, Caroline Seeley Technical Editors: Yasmin Khan, Ziva Whitelock, Roger A. YoungSecretary: Lesley TurneyTelephone: +44(0) 1223 420066; Fax: +44(0) 1223 423429; E-mail: ANALPROD@RSC.ORGFor enquiries relating to manuscripts from receipt to acceptance, contact the Publishing Division, andfor enquiries relating to manuscripts post-acceptance contact the Production Division, Royal Society ofChemistry, Thomas Graham House, Science Park, Milton Road, Cambridge, UK CB4 4WFAdvertisements: Advertisement Department, The Royal Society of Chemistry, Burlington House,Piccadilly, London, UK W1 V OBN. Telephone +44(0)171-287 3091.Fax +44(0)171-494 1 1 34.Information for AuthorsFull details of how to submit material for publicationin The Analyst are given in the Instructions toAuthors in the January issue. Separate copies areavailable on request.The Analyst publishes original research papers,critical reviews, tutorial reviews, perspectives,news articles, book reviews and a conferencediary.Original research papers. The Analystpublishes full papers on all aspects of the theoryand practice of analytical chemistry, fundamentaland applied, inorganic and organic, includingchemical, physical, biochemical, clinical,pharmaceutical, biological, environmental,automatic and computer-based methods. Paperson new approaches to existing methods, newtechniques and instrumentation, detectors andsensors, and new areas of application with dueattention to overcoming limitations and tounderlying principles are all equally welcome.Full critical reviews. These must be a criticalevaluation of the existing state of knowledge on aparticular facet of analytical chemistry.Tutorial reviews.These should be informallywritten although they should still be a criticalevaluation of a specific topic area. Some historyand possible future developments should be given.Potential authors should contact the Editor beforewriting reviews.Perspectives. These articles should provideeither a personal view or a philosophical look at atopic relevant to analytical science. Alternatively,they may be relevant historical articles.Perspectives are included at the discretion of theEditor.Particular attention should be paid to the use ofstandard methods of literature citation, includingthe journal abbreviations defined in ChemicalAbstracts Service Source Index.Whereverpossible, the nomenclature employed should followIUPAC recommendations, and units and symbolsshould be those associated with SI.Every paper will be submitted to at least tworeferees, by whose advice the Editorial Board ofThe Analyst will be guided as to its acceptance orrejection. Papers that are accepted must not bepublished elsewhere except by permission.Submission of a manuscript will be regarded as anundertaking that the same material is not beingconsidered for publication by another journal.Associate Scientific Editors.For the benefit ofall potential contributors wishing to discuss thescientific content of their paper(s) a Group ofAssociate Scientific Editors exists. Requests forhelp or advice on scientific matters can be directedto the appropriate member of the Group (accordingto discipline). Currently serving Associate ScientificEditors are listed in each issue of The Analyst (andAnalytical Communications).Manuscripts (four copies typed in double spacing)should be addressed to:H. S. Minhas, Managing Editor, orJ. F. Tyson, US Associate EditorAll queries relating to the presentation andsubmission of papers, should be addressed to thePublishing Division and any correspondenceregarding accepted papers and proofs, should bedirected to the Production Division for The Analyst.Members of the Analytical Editorial Board (whomay be contacted directly or via the Editorial Off ice)would also welcome comments, suggestions andadvice on general policy matters concerning TheAnalyst.There is no page charge.Fifty reprints are supplied free of charge.The Analyst (ISSN 0003-2654) is published monthly by The Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge,UK CB4 4WF.All orders, accompanied with payment by cheque in sterling, payable on a UK clearing bank or in US dollars payable on a US clearing bank, shouldbe sent directly to The Royal Society of Chemistry, Turpin Distribution Services Ltd., Blackhorse Road, Letchworth, Herts, UK SG6 1 HN.Turpin Distribution ServicesLtd., is wholly owned by the Royal Society of Chemistry. 1996 Annual subscription rate EC f487.00, USA $923.00, Rest of World f499.00. Purchased with AnalyticalAbstracts EC f951 .OO, USA $1 804.00, Rest of World f975.00. Purchased with Analytical Abstracts plus Analytical Communications EC f 1 123.00, USA $21 29.00,Rest of World fll51 .OO. Purchased with Analytical Communications EC f610.00, USA $1 156.00, Rest of World f625.00. Air freight and mailing in the USA byPublications Expediting Inc., 200 Meacham Avenue, Elmont, NY 1 1003.USA Postmaster: Send address changes to: The Analyst, Publications Expediting Inc., 200 Meacham Avenue, Elmont, NY 11003. Second class postage paid atJamaica, NY 11431. All other despatches outside the UK by Bulk Airmail within Europe, Accelerated Surface Post outside Europe. PRINTED IN THE UK.0 The Royal Society of Chemistry, 1996. All rights resewed. 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