Isotope ratio mass spectrometry

Abstract

Isotope Ratio Mass Spectrometry (IRMS) is a specialized technique used to provide information about the geographic, chemical, and biological origins of substances. The ability to determine the source of an organic substance stems from the relative isotopic abundances of the elements which comprise the material. Because the isotope ratios of elements such as carbon, hydrogen, oxygen, sulfur, and nitrogen can become locally enriched or depleted through a variety of kinetic and thermodynamic factors, measurement of the isotope ratios can be used to differentiate between samples which otherwise share identical chemical compositions. Several sample introduction methods are now available for commercial isotope ratio mass spectrometers. Combustion is most commonly used for bulk isotopic analysis, whereas gas and liquid chromatography are predominately used for the real-time isotopic analysis of specific compounds within a mixture. Here, highlights of advances in instrumentation and applications within the last three years are provided to illustrate the impact of this rapidly growing area of research. Some prominent new applications include authenticating organic food produce, ascertaining whether or not African elephants are guilty of night-time raids on farmers' crops, and linking forensic drug and soil samples from a crime scene to a suspected point of origin. For the sake of brevity, we focus this Minireview on the isotope ratio measurements of lighter-elements common to organic sources; we do not cover the equally important field of inorganic isotope ratio mass spectrometry.

Evaluation of n-alkanes and their carbon isotope enrichments (δ13C) as diet composition markers

“…The increased analytical capacity to separate specific compounds prior to isotope composition analysis (Muccio and Jackson, 2009) provides enormous potential to study the isotopic ratio of not only n-alkanes but also long-chain fatty alcohols and fatty acids. The possibility of generating two different types of internal markers from a single set of compounds such as n-alkanes would be a desirable feature in terms of increasing the discriminatory power of wax components.…”

Studies on Isotope Ratio Measurement of Cl by Inductively Coupled Plasma Triple-quad Mass Spectrometry

“…Isotope ratio measurement of elements is well recognized to be increasingly widespread use in disciplines such as bioavailability studies using stable isotope tracers, [1][2][3][4][5][6] isotope abundance measurements in nuclear chemistry, 6-10 the determination of isotope variations in geological, environmental and cosmic samples including age determinations, 3,4,[11][12][13][14][15][16][17][18][19] food authenticity, 3,4,20 or forensic science. 3,4,21,22 Isotope ratio measurement is also important for the production of accurate analytical results in trace element determinations by isotope dilution mass spectrometry (IDMS).…”

“…3,4,21,22 Isotope ratio measurement is also important for the production of accurate analytical results in trace element determinations by isotope dilution mass spectrometry (IDMS). [23][24][25][26][27][28][29] Isotope ratio measurements have traditionally been carried out by isotope ratio mass spectrometry (IRMS) 3,12,13,20,22 and by thermal ionization mass spectrometry (TIMS). 4,8,14,20 Disciplines of IRMS are the ability to accurately and precisely measure variations in the abundance of isotope ratios of light elements such as H, C, N, O and S. On the other hand, TIMS can cover the whole range of elements from Li to U except for the gaseous elements measured by IRMS.…”

Differentiation of Lard, Chicken Fat, Beef Fat and Mutton Fat by GCMS and EA-IRMS Techniques

“…Stable isotope mass spectrometry SIRMS is another potential analytical tool to cross-check food authenticity 10,11 .…”