Mass spectrometry isotope ratios

Isotope ratios in a sample are measured and expressed relative to internationally accepted standard samples of accurately known isotope ratios. For example, PDB (Pee Dee Belemnite CaCOs) is used as a standard for carbon its ratio is 0.0112372 [29]. Similarly, Vienna SMOW (Standard Mean Ocean Water) is the standard for oxygen and hydrogen, and air is the standard for nitrogen. Following are the commonly accepted definitions for reporting isotope ratios  

To avoid the kind of problems which trouble whole-molecule mass spectrometry it is better to use instrumentation especially designed for high precision measurements of isotope ratios isotope-ratio mass spectrometry (IRMS). 

Unlike ordinary mass spectrometers, the goal of peak focusing in IRMS is broad peaks with wide flat tops. This allows peaks to be centered on the detectors during measurements and ensures that small inaccuracies in focusing do not affect the ion current. A typical peak shape for CO2 measurements is shown in Fig. 7.8. 

Another important feature of IRMS is the provision of a dual inlet system which permits the operator to alternate the gas flowing into the ionization chamber between 

since ratios of isotopic ratios are commonly used to report isotope effect data (see Equations 7.17 and 7.18 for example), the actual numerical value of the abundance ratio of the standard is not important since it drops out from the final equation expressing the isotope effect  

Commonly used interlaboratory standards are discussed in Section 9.1.2 and listed in Tables 7.5 and 9.1. 

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This accurate measurement of the ratio of abundances of isotopes is used for geological dating, estimation of the ages of antiquities, testing athletes for the use of banned steroids, examining fine details of chemical reaction pathways, and so on. These uses are discussed in this book under various headings concerned with isotope ratio mass spectrometry (see Chapters 7, 14, 15, 16, 17, 47, and 48). 

FTICR. Fourier-transform ion cyclotron resonance GC/IRMS. gas chromatography isotope ratio mass spectrometry... 

GD/IRMS. glow discharge isotope ratio mass spectrometry HPLC. high-pressure liquid chromatography... 

IKES. ion kinetic energy spectroscopy IRMS. isotope ratio mass spectrometry ISDMS. isotope dilution mass spectrometry ITMS. ion trap mass spectrometry LA. laser ablation... 

Platzner, I.T., Modem Isotope Ratio Mass Spectrometry, Wiley, Chichester, U.K., 1997. 

S. Nitz, B. Weinreich and F. Draweit, Multidimensional gas cliromatography-isotope ratio mass spectrometry (MDGC-IRMS). Part A system description and technical requirements , 7. High Resolut. Chromatogr. 15 387-391 (1992). 

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). 

Authenticity evaluation has recently received increased attention in a number of industries. The complex mixtures involved often require very high resolution analyses and, in the case of determining the authenticity of natural products, very accurate determination of enantiomeric purity. Juchelka et al. have described a method for the authenticity determination of natural products which uses a combination of enantioselective multidimensional gas chromatography with isotope ratio mass spectrometry (28). In isotope ratio mass spectrometry, combustion analysis is combined with mass spectrometry, and the ratio of the analyte is measured versus a... 

Vol. 145. Modern Isotope Ratio Mass Spectrometry. Edited by T. J. 

CANFIELD w K (1993). Study of beta-carotene metabolism in humans using 13C-beta-carotene and high precision isotope ratio mass spectrometry. Annals of the New York Academy of Sciences 691 86-95. 

Gunther D, Heimich CA (1999) Enhanced sensitivity in laser ablation-ICP mass spectrometry using helium-argon mixtures as aerosol carrier. J Anal At Spectrom 14 1363-1368 Habfast K (1998) Fractionation correction and multiple collectors in thermal ionization isotope ratio mass spectrometry. Inti J Mass Spectrom 176 133-148... 

Richter S, Goldberg SA, Mason PB, Traina AJ, Schwieters JB (2001) Linearity tests for secondary electron multipliers used in isotope ratio mass spectrometry. Inti J Mass Spectrom 206 105-127 Rihs S, Condomines M, Sigmarsson O (2000) U, Ra, and Ba incorporation dining precipitation of hydrothermal carbonates imphcations for Ra-Ba dating of impure travertines. Geochim Cosmochim Acta 64 661-671... 

Macrocyclic Compounds in Analytical Chemistry. Edited by Yury A. Zolotov Surface-Launched Acoustic Wave Sensors Chemical Sensing and Thin-Film Characterization. By Michael Thompson and David Stone Modern Isotope Ratio Mass Spectrometry. Edited by T. J. Platzner High Performance Capillary Electrophoresis Theory, Techniques, and Applications. Edited by Morteza G. Khaledi... 

I. T. Platzner, Modern isotope ratio mass spectrometry, John Wiley Sons, Ltd, Chichester, 1997. 

Figure 14.17 Schematic diagram of the ThermoElectron liquid chromatography isotope ratio mass spectrometry chemical oxidation reactor...

Begley, I. S. and Scrimgeour, C.M. (1997) High precision 82H and 8lsO measurement for water and volatile organic compounds by continuous flow pyrolysis isotope ratio mass spectrometry. 

Binnert, C., Laville, M., Pachiaudi, C., Rigalleau, V. and Beylot, M. (1995) Use of gas chromatography isotope ratio mass spectrometry to study triglyceride metabolism in humans. Lipids 30, 869 873. 

Corr, L. T., Berstan, R. and Evershed, R. P. (2007a) Development of N acetyl methyl ester derivatives for the determination of 813C values of amino acids using gas chromatography combustion isotope ratio mass spectrometry. Analytical Chemistry 79, 9082 9090. 

Demmelmair, H. and Schmidt, H. L. (1993) Precise 813C determination in the range of natural abundance on amino acids from protein hydrolysates by gas chromatography isotope ratio mass spectrometry. Isotopenpraxis 29, 237 250. 

Hilkert, A. W., Douthitt, C. B., Schliiter, H. J. and Brand, W. A. (1999) Isotope ratio monitoring gas chromatography/mass spectrometry of D/H by high temperature conversion isotope ratio mass spectrometry. Rapid Communications in Mass Spectrometry 13, 1226 1230. 

Leckrone, K. J. and Hayes, J. M. (1998) Water induced errors in continuous flow carhon isotope ratio mass spectrometry. Analytical Chemistry 70, 2737 2744. 

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. 

McCullagh, J. S. O., Juchelka, D. and Hedges, R. E. M. (2006) Analysis of amino acid 13C abundance from human and faunal bone collagen using liquid chromatography/isotope ratio mass spectrometry. Rapid Communications in Mass Spectrometry 20, 2761 2768. 

Meier Augenstein, W. (1999) Applied gas chromatography coupled to isotope ratio mass spectrometry. Journal of Chromatography, A 842, 351 371. 

Meier Augenstein, W., Watt, P. W. and Langhans, C. D. (1996) Influence of gas chromatographic parameters on the measurement of 13C/12C isotope ratios by gas liquid chromatography combustion isotope ratio mass spectrometry. I. Journal of Chromatography, A 752, 233 241. 

Metges, C. C. and Daenzer, M. (2000) 13C gas chromatography combustion isotope ratio mass spectrometry analysis of N pivaloyl amino acid esters of tissue and plasma samples. Analytical Biochemistry 278, 156 164. 

Metges, C. C., Kempe, K. and Wolfram, G. (1994) Enrichment of selected serum fatty acids after a small oral dosage of (1 C 13)triolein and (8 C 13)triolein in human volunteers analyzed hy gas chromatography combustion isotope ratio mass spectrometry. Biological Mass Spectrometry 23,295 301. 

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