Important Information Regarding CSIA by GC-C-IRMS

Compound-specific stable isotope analysis (CSIA) is still a developing field in stable isotope analysis, accompanied by more caveats and less uniformity in analytical technique than bulk stable isotope analysis (BSIA). There are a wide variety of sample preparation, derivatization (if necessary), calibration, and quality assurance techniques employed. As a result of this lack of uniformity, best practices will vary by both analyte and application, and implementation varies across laboratories. Depending upon the compounds of interest, the UC Davis SIF conducts different calibration and quality assurance strategies. In all cases, however, the strategy will employ (1) 1 to 2 internal reference materials that are co-injected with each sample, along with (2) multiple external mixtures of pure compounds, of the same class as the analyte, that have been calibrated to primary reference materials by EA-IRMS for use in quality control and assessment, and (3) 1 or more well-known quality assurance materials of similar composition to potential sample matrices. This suite of reference materials allows us to most closely replicate the best practices employed in BSIA, as much the sample matrices and analytes of interest will allow [1].

As with BSIA, we encourage all CSIA users to include their own reference material(s) to be analyzed alongside experimental samples. In this way, analyses across multiple laboratories may be linked together through a common reference material. If you have questions regarding the selection and preparation of appropriate reference materials, we would be happy to assist you.

In an effort to best ensure a good fit between technique and application, we expect all users to be familiar with or, at minimum, develop a basic understanding of CSIA prior to submitting samples for analysis [1-6]. By submitting samples to the SIF, we understand that you have read the above information and understand the current status of CSIA, the accompanying potential limitations, and best practices. If you have any questions regarding the applicability of CSIA techniques to your research application, we are happy to discuss this with you. However, it is the responsibility of the researcher to ultimately determine whether CSIA is a suitable to the experimental design and data application.

References
[1] Jochmann, M.A. and Schmidt, T.C. 2012. Compound-Specific Stable Isotope Analysis, 1st Ed. Royal Society of Chemistry, Cambridge UK
[2] Short Course on CSIA, University of Bristol, 2003. http://www.chm.bris.ac.uk/~chidb/personal/content/simsug2003course.pdf
[3] Meier-Augenstein 2004. GC and IRMS Technology for 13C and 15N Analysis on Organic Compounds and Related Gases in Handbook of Stable Isotope techniques, Vol. 1, 1st Ed., pp. 153-176, de Groot, P.A. (Ed.) Elsevier, Amsterdam, Netherlands
[4] Sessions, A.L. Isotope-ratio detection for gas chromatography 2006. J. Sep. Sci. 29, 1946-1961
[5] Evershed R.P. et al. 2007. Compound-specific stable isotope analysis in ecology and paleoecology in Stable Isotopes in Ecology and Environmental Science, 2nd Ed., pp. 480-540. Michener, R. and Lathja K., Eds. Blackwell, Oxford, UK
[6] Blessing M. et al. 2008. Pitfalls of compound-specific isotope analysis of environmental samples. Anal. Bioanal. Chem. 390, 591–603.