Stable carbon isotope ratios

For marble provenance studies, the most successful technique seems to be the measurement, through mass spectrometry, of the abundance ratios of the stable isotopes of carbon and oxygen (116). However, no single technique appears to provide unequivocal results, especially in cases such as the different Mediterranean sources, and a combination is often necessary to arrive at an approximate place of origin (117). 

Huelsemann F., Flenker, U., Koehler, K, Schaenzer, W. (2009). Effect of a controlled dietary change on carbon and nitrogen stable isotope ratios of human hair. Rapid Communications in Mass Spectrometry Vol 23, pp. 2448-2454. 

Recently it has been recognised that the carbon isotope composition of small amounts of plant material may be used to assess differences inpi/pa and W (Farquhar et al., 1982). There are two stable isotopes of carbon, and C, which are in the molar ratio 1 89 in the atmosphere. During assimilation of atmospheric CO2 the plant fixes a smaller ratio... 

Farquhar, G.D., Hubick, K.T., Condon, A.G. Richards, R.A. (1988). Carbon isotope fractionation and plant water-use efficiency. In Applications of Stable Isotope Ratios to Ecological Research, ed. P.W. Rundel, J.R. Ehleringer K.A. Nagy, pp.21 0. New York Springer-Verlag. 

For our first tree sequence [28-32] we measured D/H by reacting sawdust with uranium to produce H2, 99 percent quantitatively. For measurement of 180/160, we modified the method of Rittenberg and Pontecorvo [33] by carrying it out at very high temperatures, 99 percent quantitatively. The temperature must be 525 °C if it is lower, the reaction is not quantitative see the section on our chemistry later in this paper. To measure the stable isotope ratio in carbon, we burned sawdust to completion in oxygen. 

If the stable isotope ratio of 13C/12C is to be further measured in tree rings and interpreted as an indicator of climate variation, (and we have barely begun to initiate its use as a thermometer in the present work, confining our measurements to the stable isotopes in water, because water is so abundant compared to carbon dioxide and because the dependence of its isotope ratios is relatively simple compared with those of carbon dioxide), some more sophisticated considerations must be given to the distribution of carbon dioxide among the reservoirs on the surface of the earth. 

Although GC-C-IRMS systems that can measure the chlorine isotopic composition of individual chlorinated hydrocarbons are currently unavailable, it is clear that chlorine isotope analysis is also a useful technique to consider for study [614,677,678]. Measurement of chlorine stable isotope ratios in natural samples such as rocks and waters has become routine [626,679,680], but few measurements of chlorine isotopes in chlorinated aliphatic hydrocarbons have been reported [614]. A chlorine isotope effect was found in ferf-butyl chloride [681], demonstrating that 37Cl is more strongly bound to carbon than is 35Cl. Significant differences in the <5i7Cl values of some atmospheric chlorinated... 

A reliable authenticity assessment is concluded from the simultaneous consideration of multielement IRMS and enantioselective analysis. The differences of the stable isotope ratios of linalool and linalyl acetate are depicted as a three-dimensional plot of A values (d values of linalool minus d values of linalyl acetate for oxygen, hydrogen and carbon) (Fig. 17.15). This plot shows that the commercial samples S1-S5 are different from all the other samples investigated. Linalool and linalyl acetate of S1-S5 definitely are not genuine lavender oil compounds. 

M. W. Todd, J. Glasser, A. A. Kachanov, B. A. Paldus, T. G. Spence, and R. N. Zare, "Stable Isotope Ratios Using Cavity Ring-Down Spectroscopy Determination of, C/I2C for Carbon Dioxide In Human Breath,"... 

Measurements of carbon and nitrogen stable-isotope ratios were made by using a Finnigan MAT 251 or a Delta S isotope-ratio mass spectrometer. Results are reported versus atmospheric nitrogen (N) or PeeDee Belemnite (C) as standards and calculated as ... 

Carbon stable isotope ratios in Olivella biplicata shell beads sourcing, 180-185/... 

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