Isotopes, stable mass spectrometry

In recent years, together with enantioselective analysis, the determination of the natural abundance of stable isotopes by means of stable isotope ratio mass spectrometry (TRMS) can be very useful for the assignment of the origin of foods and food ingredients, and of authenticity evaluation (24). 

Dizdaroglu, M. (1993). Quantitative determination of oxidative base damage in DNA by stable isotope-dilution mass spectrometry. FEBS Lett. 315, 1-6. 

Macko, S. A., Uhle, M. E., Engel, M. H. and Andrusevich, V. (1997) Stable nitrogen isotope analysis of amino acid enantiomers by gas chromatography combustion/isotope ratio mass spectrometry. Analytical Chemistry 69, 926 929. 

Mykytiuk et al. [184] have described a stable isotope dilution sparksource mass spectrometric method for the determination of cadmium, zinc, copper, nickel, lead, uranium, and iron in seawater, and have compared results with those obtained by graphite furnace atomic absorption spectrometry and inductively coupled plasma emission spectrometry. These workers found that to achieve the required sensitivity it was necessary to preconcentrate elements in the seawater using Chelex 100 [121] followed by evaporation of the desorbed metal concentrate onto a graphite or silver electrode for isotope dilution mass spectrometry. 

TI is a very precise and accurate method in stable isotope ratio measurements and quantification of inorganic elements, for example, by isotope dilution mass spectrometry [8]. Because TI is a continuous ion source, it could be coupled to any analyzer that is suitable for such sources. However, because the strength of TI lies in the quantitative precision and accuracy, sector analyzers are preferred to ensure maximum quality. 

Meier-Augenstein, W. (2002). Stable isotope analysis of fatty acids by gas chromatography-isotope ratio mass spectrometry. Analytica Chimica Acta 465 63-79. 

AUTOMATED ANALYSIS OF STABLE ISOTOPES OF H, C, N, O AND S BY ISOTOPE RATIO MASS SPECTROMETRY 151... 

Barrie, A., Prosser, S.J. Automated analysis of light-element stable isotopes by isotope ratio mass spectrometry. Unpublished Materials. Europa Scientific Ltd. Crewe, Cheshire, England, 2000. 

While competitive methods to determine KIE s are free from errors due to differences in reaction conditions (impurities, temperature, pH, etc.) they do require access to equipment that allows high precision measurements of isotope ratios. The selection of an appropriate analytical technique depends on the type of the isotope and its location in the molecule. For studies with stable isotopes the most commonly used technique (and usually the most appropriate) is isotope ratio mass spectrometry (IRMS). 

Pickup JF, McPherson K. 1976. Theoretical considerations in stable isotope dilution mass spectrometry for organic analysis. Anal Chem 48 1885-1890. 

Mosandl A, Enantioselective capillary gas chromatography and stable isotope ratio mass spectrometry in the authenticity control of flavors and essential oils, Food Rev Int. 537—SSA, 1995. 

System (3) described the use of stable-isotope-dilution mass spectrometry for the simultaneous determination of cortisol, cortisone, prednisolone, and prednisone in plasma [177]. Cortisol, cortisone, prednisolone, and prednisone were simultaneously extracted from acidified plasma on a Sep-Pak Ci8 cartridge. The column was eluted with methanol, the eluent evaporated, and the residue compounds reacted to their bismethylenedioxy-3-heptafluoro-n-butyryl derivatives by treatment with formaldehyde and heptafluoro-n-butyric anhydride. The derivatives were... 

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