Stable isotopes isotope fractionation

Drenzer NJ, T1 Eglinton, CO Wirsen, HD May, Q Wu, KR Sowers, CM Reddy (2001) The absence and application of stable carbon isotope fractionation during the reductive dechlorination of polychlorinated biphenyls. Environ Sci Technol 35 3310-3313. [Pg.634]

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Winner, W.E., Smith, C.L., Koch, G.W., Mooney, H.A., Bewley, J.D., and Krouse, H.R. (1981) Rates of emission of H2S from plants and patterns of stable sulfur isotope fractionation. Nature 289, 672-673. [Pg.684]

Figure 2 Schematic potential energy curve for the hydrogen molecules with scale at bottom of the curve exaggerated to show relation between n = 0 vibrational energy levels of the four isotopic forms of the molecules. Note that molecules containing a heavy isotope are more stable (have higher dissociation energies) than molecules with a light isotope. Isotope fractionations between molecules are explained by differences in their zero-point energies...

$Figure 2 Schematic potential energy curve for the hydrogen molecules with scale at bottom of the curve exaggerated to show relation between n = 0 vibrational energy levels of the four isotopic forms of the molecules. Note that molecules containing a heavy isotope are more stable (have higher dissociation energies) than molecules with a light isotope. Isotope fractionations between molecules are explained by differences in their zero-point energies...$

Mazeas L., Budzinski H., and Raymond N. (2002) Absence of stable carbon isotope fractionation of saturated and polycyclic aromatic hydrocarbons during aerobic bacterial degradation. Org. Geochem. 33, 1259-1272. [Pg.5045]

TABLE 8. Stable Carbon Isotopic Fractionation for Fulvic Acid from Groundwater... [Pg.97]

Zeebe, R. E. 2005a. Stable boron isotope fractionation between dissolved B(OH)3 and B(OH)4. Geochimica et Cosmochimica Acta, 69, 2753-2766. [Pg.57]

Stable oxygen isotopic fractionation in carbonate material is also heavily temperature dependent and since the seminal publications of Urey (1947) and McCrea (1950), much work has been under-... [Pg.156]

Descolas-Gros C, Fontugne M (1990) Stable carbon isotope fractionation by marine phytoplankton during photosynthesis. Plant Cell Environment 13 207-218... [Pg.273]

Burkhardt S, Riebesell U (1997) C02 availabihty affect elemental composition (C N P) of the marine diatom Skeletonema costatum. Mar Ecol-Prog Ser 67-76 10 Burkhardt S, Riebesell U, Zondervan 1 (1999a) Effects of growth rate, CO2 concentration, and cell size on the stable carbon isotope fractionation in marine phytoplankton. Geochim Cosmochim Acta 62 3729-3741... [Pg.598]

Burkhardt S, Riebesell U, Zondervan 1 (1999b) Stable carbon isotope fractionation by marine phytoplankton in response to daylength, growth rate, and CO2 availability. Marine Ecology-Progress Ser 184 31-41... [Pg.598]

The Mechanism of Stable Carbon Isotope Fractionation ( C vs. C) and Regularities in Their Distribution in Jurassic and Cretaceous... [Pg.1]

Tiehm A, Schmidt KR, Pfeiffer B, Heidinger M, Ertls S. (2008). Growth kinetics and stable carbon isotope fractionation during aerobic degradation of cis-l,2-dichloroethene and vinyl chloride. Water Research 42 2431-2438. [Pg.415]

In practice, [X]t and [X]e may be expressed in any units that are proportional to their concentration or abundance. For radioactive determinations, either total activity or specific activity may be used for stable isotopes, mole fraction may be employed. The expression given above for u indicates that the exchange process is always of first order, and it will remain so provided tracer quantities are employed. In practice, it means that the plot of log(l-F) versus time wiU be a straight line, with a slope proportional to the exchange velocity, Uex (Purich AUison, 1980). [Pg.337]

Throughout this chapter, variations in isotopic compositions will be described using conventional stable isotope notation. Fractionation factors are defined in terms of alpha, with... [Pg.318]

In nature, oxygen occurs in three stable isotopic species oxygen-16 [14797-70-7] O, 99.76% oxygen-17 [13968-48-4], 0.038% and oxygen-18 [14797-71-8], 0.20% (7). Commercial fractional distillation of water produces concentrations of as high as 99.98% concentrations up to 55% are also produced. The isotope has been used to trace mechanisms of organic reactions. [Pg.475]

Irreversible processes are mainly appHed for the separation of heavy stable isotopes, where the separation factors of the more reversible methods, eg, distillation, absorption, or chemical exchange, are so low that the diffusion separation methods become economically more attractive. Although appHcation of these processes is presented in terms of isotope separation, the results are equally vaUd for the description of separation processes for any ideal mixture of very similar constituents such as close-cut petroleum fractions, members of a homologous series of organic compounds, isomeric chemical compounds, or biological materials. [Pg.76]

Stable isotope analyses of the organic fraction of bone and of food samples was carried out on a Micromass Prism Mass Spectrometer in the Stable Isotope Laboratory, Department of Physics, University of Calgary, under the direction of H.R. Krouse. Collagen samples were combusted in a Carlo Erba gas analyser which provides information on the carbon and nitrogen content of the samples andintroduces Nior CO gases into the mass spectrometer for analysis of nitrogen or carbon stable isotopes, respectively. [Pg.4]

Stable Isotope Analysis, Bone Organic Fraction... [Pg.8]

Krueger, H.W. and Sullivan, C.H. 1984 Models for carbon isotope fractionation between diet and bone. In Tumland, J.R. and Johnson, P.E., eds.. Stable Isotopes in Nutrition. Washington D.C, American Chemical Society Symposium Series, No. 258 205-220. [Pg.20]

Macko, S.A., Estep, M.L.E., Engel, M.H. and Hare, RE. 1986 Kinetic fractionation of stable nitrogen isotopes during amino acid transamination. Geochimica et Cosmochimica Acta 50 2143-2146. [Pg.60]

Hohson, K.A. and Clark, R.G. 1992 Assessing avian diets using stable isotopes 11 factors influencing diet-tissue fractionation. The Condor 94 181-188. [Pg.257]

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