ChromSA online lecture by Adriaan Marais

Abstract: Stable isotope ratio mass spectrometry (IRMS) allows the accurate measurement of small differences in the abundances of isotopes such as 2H/1H, 13C/12C, 15N/14N, and 18O/16O, in a wide variety of sample types applicable to numerous disciplines e.g.  geochemistry, environmental science, food science, and forensic science. The underlying principle is the fractionation of light (e.g. 12C) versus heavy isotopes (e.g. 13C) occurring during any natural or synthetic chemistry process. The differential incorporation of light and heavy isotopes in a chemical structure, as directly related to the starting material and specific process that originates that structure, thus leads to a specific subset of heavy/light isotope ratios that may impart a degree of uniqueness to a compound. Simply put, a chemical compound originating under specific conditions may display isotope ratios that are unique and dissimilar to the same compound originating under differing conditions. The measured isotope ratios are often expressed as the…