IAEA-TECDOC-825 Reference and intercomparison materialsfor stable isotopes of light elements Proceedings consultantsa of meeting held Vienna,in December1-3 1993 INTERNATIONAL ATOMIC ENERGY AGENCY The IAEA does not normally maintain stocks of reports in this series. However, microfiche copies of these reports can be obtained from IN IS Clearinghouse International Atomic Energy Agency Wagramerstrasse 5 P.O. Box 100 A-1400 Vienna, Austria Orders should be accompanied by prepayment of Austrian Schillings 100,- in the form of a cheque or in the form of IAEA microfiche service coupons which may be ordered separately from the I MIS Clearinghouse. The originating Section of this publication in the IAEA was: Isotope Hydrology Section International Atomic Energy Agency Wagramerstrasse5 0 10 P.Ox Bo . A-1400 Vienna, Austria REFERENCE AND INTERCOMPARISON MATERIALS FOR STABLE ISOTOPE LIGHF SO T ELEMENTS IAEA, VIENNA, 1995 IAEA-TECDOC-825 ISSN 1011-^4289 © IAEA, 1995 Printed by the IAEA in Austria September 1995 FOREWORD stable Th e isotope compositio chemicaf no l elements varie naturan si l compounds as a consequence of the slightly different physico-chemical behaviour of isotopes. In particular, isotope f lighso t elements, which hav largese eth t relative mass differencd an e therefore als mose oth t different behaviour, sho widese wth t variations r instanceFo . , natural waters exhibit variation 218e e HIO/th th 1 H16f f so o O 1:2o rati t d 1:1.1 o ratit p ,an o u p ou , 16 2 1 16 due to the different evaporation-condensation rate of 'H2 O with respect to H H O and 18 'H2 O. These variation ranges become even l widenaturaal f i r l compounds containing hydrogen and/or oxygen are considered. The possibility of measuring the stable isotope relative variations with high precision, using mass spectrometry, promoted the rise of new fields of research in geochemistr hydrologd an y y and, more recently environmentan i , l studies e steadTh .y growth of these investigations and of their practical applications has emphasized the need for high quality isotopic standards and intercomparison samples, with well determined isotopic composition intercalibratioe th r fo , analyticaf no l technique resultd san s among laboratories Although stable isotope standards have existed for more than three decades, there was a need to re-examine the whole matter, in view of the expansion of isotope applications ancontinuoue dth s improvement refinementd san analyticae th f o s l techniques, which make it possible to detect smaller and smaller isotopic variations. Just to give an example, up to r twento n te y years ago ,precisioa f ±0.no determinatioe 1 th % n oi 13f no C/ 12C ratio relative variation generalls swa y considered acceptabl eved ean n good t wit e applicatioBu hth . f no carbon stable isotopes to study the atmospheric carbon dioxide with the aim of improving the understanding of the global carbon cycle, the long-term analytical precision had to be increased by an order of magnitude to detect the long term trend of less than 0.02%e per year, superimposed on the seasonal variations. The laboratories involved in this work had, and still havethrougo g o t , h lengthy check runintercomparisond san analyticae th f so d an l sampling techniques ordesurn e i ,b eo t r tha date th ta obtaine differenn di t place fulle sar y consistent. pase th t r thirtFo y years Internationae th , l Atomic Energy Agency, througs hit Sectio f Isotopno e Hydrology bees ha , n activfiele preparatiof th do n ei distributiod nan f no stable isotope referenc intercomparisod ean n material determinatioe th r sfo isotopie th f no c composition of natural compounds. The organization of the Consultants Meeting on Stable Isotope Standards and Intercomparison Materials held in Vienna from 1 to 3 December 1993, the fifth of this type (the previous meetings took place in 1966, 1976, 1983 and 1985), called for a review and a discussio e characteristicsth f no , qualit availabilitd an y e existinth f o y g standardd an s intercalibration assessmenmaterialsn a r fo materialsd w needf an ,t o ne r sfo vien i , recenf wo t developments and applications. A large part of the discussions was devoted to the new materials prepared for sulphur isotope analysis and the analytical requirements for highly precise isotopic analysis of CO2. The papers presented at the meeting are assembled in this volume. For the first time, two institutions were represented which are actively engaged in the field of standardization and intercalibration of isotopic measurements: the Institute for Reference Material Measurementd san Commissioe th f so Europeae th f no n Communities, Geel, Belgiume Nationath d an ,l Institut r Standardfo e d S TechnologU an s e th f o y Department of Commerce, Gaithersburg, Maryland, USA. It is hoped that this marks the beginnin newa f go , fruitful collaboration betwee IAEe nth thesd Aan e institutions. EDITORIAL NOTE preparingIn this publication press,for IAEAthe staffof have pages madethe up from the original manuscripts submittedas authors.the viewsby The expressed necessarilynot do reflect those of the governments of the nominating Member States or of the nominating organizations. Throughout textthe names Memberof States retainedare theyas were when textthe was compiled. The use of particular designations of countries or territories does not imply any judgement by publisher,the legalthe IAEA,to the status as of such countries territories,or of their authoritiesand institutions delimitationthe of or of their boundaries. The mention of names of specific companies productsor (whether indicatednot or registered)as does implyintentionnot any infringeto proprietary rights, should construednor be it an as endorsement recommendationor partthe IAEA. ofon the The authors are responsible for having obtained the necessary permission for the IAEA to reproduce, translate or use material from sources already protected by copyrights. CONTENTS Summar meetine th f yo g ...........................................................................7 . Standards and intercomparison materials distributed by the International Atomic Energy Agency for stable isotope measurements ........................................... 13 Gonfiantini,R. Stichler,W. RozanskiK. Reportin f stablgo e carbon, hydrogen oxyged an , n isotopic abundances..................1 3 . T.B. Coplen Audit of VSMOW distributed by the United States National Institute of Standards and Technology ...................................................................................5 3 . T.B. Coplen, J. Hopple Sulphur isotope standards ..........................................................................9 3 . B.W. Robinson Variation sulfue th n rsi isotope compositio ........................................T CD f no 7 4 . G. Beaudoin, B.E. Toy lor,. Rumble. D . Thiemens M , HI Compariso conventional-SOe th f no laser-SFe th d 2an 6 methods: Implicationr sfo the sulfur isotope scale ...........................................................................9 4 . G. Beaudoin, B.E. Taylor Interlaboratory compariso f referencno e material r nitrogen-isotope-ratisfo o measurements ...................................................................................... 51 J.K. Böhlke, T.B. Coplen Interlaboratory compariso materialw ne f nr o carbo fo s oxyged nan n isotope ratio measurements ...................................................................................... 67 W. Stichler Carbon, oxyge hydroged nan n isotopic intercompariso f fruid no an t vegetable juices ...................................................................................5 7 . J. Koziet, F. Pichlmayer, A. Rossmann isotopie Th c compositio Groningee th f no n GS-1 GS-2d 9an 0 pur2 standardeCO s ...1 8 . H.A..]. Meiier measurementO ô e reporA th IAEe n th o tf Aso cellulose intercompariso18 n material IAEA-C3 ................................................................................. 85 W.M. Buhay, B.B. Wolfe, R.J. Elgood, T.W.D. Edwards f platinizeo e Us d magnesiu reagens ma t replacing zin hydrogen ci n isotope analysis .............................................................................................7 8 . S. Halas, B. Jasinska Carbon isotope (14C, 12C) measurements to quantify sources of atmospheric carbon monoxid urban ei r ...........................................................................nai 3 9 . O.A. Klouda, M.V. Connolly The carbon dioxide isotopic measurement process: Progress at NIST on measurements, reduction algorithms and standards ......................................... Ill R.M. Verkouteren, G.A. Klouda, L.A. Currie High precision stable isotope measurements of atmospheric trace gases .................. 131 C.E. Allison, R.J. Francey Recommendations for the reporting of stable isotope measurements of carbon and oxygen in CO2 gas ................................................................................ 155 C.E. Allison, R.J. Francey, H.A. Meijer Lis f Participanto t s ..................................................................................3 16 . IAEA report publicationd san stabln so e isotope standard measuremend san t intercomparison ...................................................................................5 16 . SUMMARY OF THE MEETING n thiI s summar e fiftth h f o yIAE A Meetin n Stablo g e Isotope Standardd an s Intercomparison Materials e majoth , r conclusions e recommendationreacheth d an d s formulated at the meeting are presented. They are submitted to the community of those intereste