Isotope ratio measurements new developments and a

Authors: Klaus G Heumann Torsten C Schmidt

Publish Date: 2013/02/15

Volume: 405, Issue: 9, Pages: 2747-2748

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Abstract

After 2004 and 2008 Vols 378/2 and 390/2 this is the third issue of Analytical and Bioanalytical Chemistry to contain papers on new developments and applications in isotope ratio measurements Whereas Klaus Heumann was guest editor for the two previous special issues in this issue Torsten Schmidt joins him as guest editor for the first time His involvement with this collection of papers strongly reflects the increasing importance of compoundspecific stable isotope analysis one of his core research areas on which with Maik Jochmann he has recently published a monograph “Compoundspecific Stable Isotope Analysis” see corresponding book review in this issue A total of 24 manuscripts describing new instrumentation methodological questions for example normalization and the use of certified isotope reference materials isotopelabeling experiments determination of natural isotope signatures applications in archeology and in clinical and nuclear chemistry and isotope dilution analysis demonstrate the broad range of modern precise and accurate isotope ratio measurements This great variety of applications also clearly shows that increasing attention is being focused on isotope ratio determinations in modern analytical chemistry A recently published textbook “Isotopic Analysis” by Frank Vanhaecke and Patrick Degryse which is also reviewed in this issue confirms this trend Another interesting trend compared with the earlier collections of papers on this topic is that thermal ionization mass spectrometry TIMS is no longer predominant in current applications Although TIMS still has some important niches of application in nuclear and geochemistry it has frequently been substituted by ICP–MS because of its advantages of simpler sample preparation and multielement capability and also because some elements for example refractory and precious metals are not easily accessible to TIMS On the other hand gas chromatography coupled with an isotope ratio mass spectrometer GC–IRMS and a combustion interface for converting organic molecules into CO2 and N2 for 13C/12C and 15N/14N ratio measurements respectively by electron impact ionization is increasingly used for new applications in compoundspecific isotope analysis Furthermore the more recently introduced hyphenation with liquid chromatography for carbonisotope analysis of compounds not or hardly amenable to GC separation has been demonstrated One “Technical Note” reports the first isotope ratio measurements with a commercially available Mattauch–Herzog ICP–MS which was constructed for simultaneous mass detection However future improvements of this instrument will show whether this type of mass spectrometer can become an alternative to highresolution multicollector systems for precise isotope ratio determinationsA Feature Article by Willi Brand on “Atomic weights not so constant after all” may be of general interest to all natural scientists This article explains why IUPAC’s Commission on Isotopic Abundances and Atomic Weights recently decided to substitute fixed atomic weights for ten elements by atomic weight intervals More precise isotope ratio measurements of the isotope variation of the corresponding natural and commercial substances during the last two decades led to this decision Whereas for the light elements for example hydrogen carbon and oxygen isotope variations have been known for a long time those for heavy metals for example thallium which is one of the ten elements for which the change has been made were discovered by highly precise isotope ratio measurements especially by use of multicollector MCICP–MS systems This substantial improvement in isotope ratio determinations is also the reason why natural isotope variations of so called “nontraditional” heavy elements are increasingly investigated The review by T Hirata emphasizes the importance of this topic The early isotopeabundance determinations of Alfred OC Nier lasted for a long time but the introduction of MCICP–MS systems to isotope ratio measurements has substantially improved knowledge of natural isotope variations in the past especially for heavy metals Thus it must be expected that in the future the fixed atomic weight will be substituted by an interval for other elements alsoAs a tribute to the pioneering work of AOC Nier the cover of this issue prepared by Maik Jochmann shows an adaptation of a popular photograph of Niet as a young scientist in front of a nuclide chart sketch holding the glass mass spectrometer with which he conducted measurements relating to uranium fissionThe guest editors are very pleased by the great number of manuscripts received their high quality and the many different aspects covered We therefore hope that readers of ABC will also enjoy this collection of papers on new developments and applications in isotope ratio measurements

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