Isotope ratio mass spectrometry carbon

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... 

Silfer, J. A., Engel, M. H., Macko, S. A. and Jumeau, E. J. (1991). Stable carbon isotope analysis of amino acid enantiomers by conventional isotope ratio mass spectrometry and combined gas chromatography isotope ratio massspectrometry. Analytical Chemistry 63, 370 374. 

The reaction was second order in acid and first order in substrate, so both rearrangements and the disproportionation reaction proceed via the doubly-protonated hydrazobenzene intermediate formed in a rapid pre-equilibrium step. The nitrogen and carbon-13 kinetic isotope effects were measured to learn whether the slow step of each reaction was concerted or stepwise. The nitrogen and carbon-13 kinetic isotope effects were measured using whole-molecule isotope ratio mass spectrometry of the trifluoroacetyl derivatives of the amine products and by isotope ratio mass spectrometry on the nitrogen and carbon dioxide gases produced from the products. The carbon-12/carbon-14 isotope... 

The nitrogen and carbon-13 kinetic isotope effects found using the N- N, die 1,1/-13C2 and die 4,4/-13C2 substrates were measured by whole-molecule isotope ratio mass spectrometry on die bis-(triduoroacetyl) derivative. 

Carbon kinetic isotope effects on enzyme-catalyzed decarboxylations are among the most intensively studied enzyme reactions. This is because of the central role that carbon dioxide plays in plant metabolism and also because precise kinetic measurements are relatively easy to obtain since the carbon dioxide liberated in the reaction can be immediately analyzed using isotope ratio mass spectrometry. 

Isotope ratio mass spectrometry (IR-MS) makes use of these facts to determine the origin or the age of a sample. For convenience, the minor changes in isotopic ratios are expressed using the delta notation stating the deviation of the isotopic ratio from a defined standard in parts per thousand (%c). [8,10] The delta value of carbon, for example, is calculated from... 

Platzner, I.T. Applications of Isotope Ratio Mass Spectrometry, in Modem Isotope Ratio Mass Spectrometry, John Wiley Sons Chichester, 1997 pp. 403-447. Beavis, R.C. Chemical Mass of Carbon in Proteins. Anal. Chem. 1993, 65,496-497. Carle, R. Isotopen-Massenspektrometrie Grandlagen und An-... 

Carbon isotope fractionation effects of individual compounds were observed in living organisms and also as a result of enzymatic isotope effects and reaction kinetics in biological systems. Such fractionation effects have to be examined by isotope ratio mass spectrometry in order to understand specific processes in life sciences or in environment.75... 

High precision isotope ratio mass spectrometry permits reliable measurement of the small changes in isotopic distributions which occur in the reactions of molecules with natural abundance incorporations, especially for experiments with isotopes of carbon, nitrogen or oxygen [35]. An alternative of growing importance is the use of NMR spectroscopy to monitor similar changes for 13C and deuterium at natural abundance [36]. 

The additional measurement of 13c/l2C ratios in carbonaceous aerosols by isotope ratio mass spectrometry provides information concerning fractionation during chemical conversion of carbon-containing atmospheric species. However, 13c/l2C ratios, expressed in terms of the del value, 513c,... 

Finally, the del value is zero when the sample and the standard have the same isotopic composition. The international standards for O, C, H, N, and S are Standard Mean Ocean Water (SMOW), Pee Dee Belemnite (PDB) carbonate fossil, SMOW, atmospheric nitrogen (N2), and the Canyon Diablo Triolite (CDT) iron meteorite, respectively (table 7.6 Fame, 1986). More specifically, the13C/12C of natural materials and standards is determined using isotope-ratio mass spectrometry (for details, see Hayes, 1983 Boutton, 1991). 

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