Compound Specific Isotope Analysis

Jarman WM, A Hilkert, CE Bacon, JW Collister, K Ballschmiter, RW Risebrough (1998) Compound-specific carbon isotopic analysis of Arochlors, Clophens, Kanechlors, and Phenoclors. Environ Sci Technol 32 833-836. 

Mass spectrometry can be specific in certain cases, and would even allow on-line QA in the isotope dilution mode. MS of molecular ions is seldom used in speciation analysis. API-MS allows compound-specific information to be obtained. APCI-MS offers the unique possibility of having an element- and compound-specific detector. A drawback is the limited sensitivity of APCI-MS in the element-specific detection mode. This can be overcome by use of on-line sample enrichment, e.g. SPE-HPLC-MS. The capabilities of ESI-MS for metal speciation have been critically assessed [546], Use of ESI-MS in metal speciation is growing. Houk [547] has emphasised that neither ICP-MS (elemental information) nor ESI-MS (molecular information) alone are adequate for identification of unknown elemental species at trace levels in complex mixtures. Consequently, a plea was made for simultaneous use of these two types of ion source on the same liquid chromatographic effluent. 

Compound-specific Stable Isotopes in Organic Residue Analysis in Archaeology... 

The aims of this contribution are to (i) consider the theoretical principles underlying the use of compound-specific stable isotope analysis in archaeology (ii) consider the practical aspects of undertaking compound-specific stable isotope analyses and (iii) demonstrate the value of linking the structures of amino acids, fatty acids and/or sterols, to their compound-specific stable isotope values to achieve new insights into variations in metabolism and environment in order to enhance archaeological interpretations. 

Figure 14.5 Schematic diagram of instrumental variants of stable isotope analysis providing either bulk or compound specific stable isotope values...

Figure 14.6 Generalised analytical protocol for the compound specific stable isotope analysis of free and building block components of complex archaeological materials...

Derivatisations for Compound-specific Stable Isotope Analysis... 

GC-C-IRMS instrumentation enables the compound-specific isotope analysis of individual organic compounds, for example, n-alkanes, fatty acids, sterols and amino acids, extracted and purified from bulk organic materials. The principle caveat of compound-specific work is the requirement for chemical modification, or derivatisation, of compounds containing polar functional groups primarily to enhance their volatility prior to introduction to the GC-C-IRMS instrument. Figure 14.7 summarises the most commonly employed procedures for derivatisation of polar, nonvolatile compounds for compound-specific stable isotope analysis using GC-C-IRMS. 

Bowen, G. J. and Revenaugh, J. (2003) Interpolating the isotopic composition of modern meteoric precipitation. Water Resources Research 39(10), 1299 Brand, W. A., Tegtmeyer, A. R. and Hilkert, A. (1994) Compound specific isotope analysis extending toward 15N/14N and 180/160. Organic Geochemistry 21, 585 594. 

Fogel, M. L. and Tuross, N. (2003) Extending the limits of palaeodietary studies of humans with compound specific carbon isotope analysis of amino acids. Journal of Archaeological Science 30, 535 545. 

Reber, E. A. and Evershed, R. P. (2004a) How did Mississippians prepare maize The application of compound specific carbon isotopic analysis to absorbed pottery residues from several Mississippi Valley sites. Archaeometry 46, 19 33. 

Styring, A. K., Sealy, J. C. and Evershed, R. P. (in press) Resolving the bulk 81SN values of ancient human and animal bone collagen via compound specific nitrogen isotope analysis of constituent amino acids. Geochimica et Cosmochimica Acta. 

Finally, Chapters 14 16 deal with innovative applications in this field such as mass spectrometric compound-specific isotopic analysis, secondary ion mass spectrometry... 

SIMS) to map specific compounds in cross-sections, and atomic isotopic analysis for dating using accelerator mass spectrometry (AMS). 

The synthesis, analysis and applications of labeled compounds is an area in which basic and applied research go hand-in-hand. Over the last quarter of a century the field has seen considerable expansion as reflected in the emergence of a specific journal (Journal of Labeled Compounds and Radiopharmaceuticals) and the publication of the proceedings of international conferences held at three-yearly intervals. The formation of the International Isotope Society is also an indication of the increasing importance of isotopes and isotopically labeled compounds. 

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