Isotope mercury

The first Mossbauer measurements involving mercury isotopes were reported by Carlson and Temperley [481], in 1969. They observed the resonance absorption of the 32.2 keV y-transition in (Fig. 7.87). The experiment was performed with zero velocity by comparing the detector counts at 70 K with those registered at 300 K. The short half-life of the excited state (0.2 ns) leads to a natural line width of 43 mm s Furthermore, the internal conversion coefficient is very large (cc = 39) and the oi pj precursor populates the 32 keV Mossbauer level very inefficiently ( 10%). 

Smith CN, Kesler SE, Klaue B, Blum J (2005) Mercury isotope fractionation in fossil hydrothermal systems. Geology 33 825-828... 

Unlike the reactions of GEM in solution, experimental data on the gas-phase reactions of elemental mercury with some atmospheric oxidants are limited due to challenges including complexity of reactions, the low concentrations of species at atmospheric conditions, the low volatility of products, sensitivity to temperature and pressure, and the strong effects of water vapour and surface on kinetics. The possible effects and distribution of mercury isotope fractionation have not been analysed in any of the studies. The isotopes dilute the signal and mean that with current mass spectrometry techniques, ambient RGM compounds can not be identified. The possibility of theoretically predicting the thermochemistry of mercury-containing species of atmospheric interest is important and is complementary to laboratory and field studies. 

Ambient Isotopic Studies of Mercury—Biological Fractionation of Mercury Isotopes... 

Mercury has a relatively even distribution of its seven stable isotopes (196, 0.15% 198,10.0% 199, 16.7% 200,23.2% 201,13.2% 202,29.8% 204,6.8% Friedlander et al., 1981 Lauretta et al., 2001). This pattern presented cosmochemists with a formidable task when mercury isotopic distributions in meteorites were examined (e.g., Jovanovic and Reed, 1976 Thakur and Goel, 1989). Analytical difficulties apparently resulted in inaccurate determinations of the bulk abundance and isotopic composition of some meteorites, leading to the so-called mercury problem examined meteorites did not show the same bulk abundance and isotopic distribution as terrestrial material (Grevesse, 1970 Lauretta et al., 1999). Subsequent advances in mass spectrometry, and especially the development of multi-collectors. 

Evans R.D., Hintehnann H. and Dillon P.J. (2001) Natural variation in mercury isotope ratios of coals and cinnabars. Proc. 6th Int. Conf. Mercury Glob. Pollut. Minimata, Japan, Oct. 15-19. 

Klaue B., Kesler S. E., Blum J. D. (2000) Investigation of natural fractionation of stable mercury isotopes by inductively coupled plasma mass spectrometry. In Proc. Int. Conf. Heavy Metals Environ. Ann Arbor, Ml, August 6-10. 

Krupp E. M., Pecheyran C., and Donard O. F. X. (2003) Investigation on the mercury isotope distribution of mercury species (MMHg and Hg2 ) in different fish tissue samples. In Abstracts of the 2003 European Winter Conference on Plasma Spectrochemistry, Garmisch-Partenkirchen, Germany, January, 12-17. 

Precipitation For example (1) Iodine isotopes After adding a drop of AgN03 solution, dry naturally in open air. (2) Mercury isotopes Dry in an atmosphere of H2S. 

Hintelman H and Ogrinc N (2003) Determination of stable mercury isotopes by ICP/MS and their application in environmental studies. In Cai Yand Braids OC, eds. Biogeochemistry of Environmentally Important Trace Elements, pp. 321-338. American Chemical Society. 

In conclusion, considerable discrepancy afflicts reported data on loss of mercury from samples during preparation and digestion. It is, thus, important to adapt the procedure to real samples and to carefully evaluate recovery, matrix effects, and detection limits for these samples. Mostly, such tests are carried out on spiked samples, but a more distinguished approach is to study the recovery through the different steps of the procedure by use of radioactive mercury isotopes. The most reliable data should be those obtained on samples, in which the mercury has been incorporated in vivo (e.g. Clarkson and Greenwood, 1970 LaFleur, 1973 Stein et al., 1974 Iyengar et al., 1978 Stuart, 1978a Semu et al., 1985). 

Trauser and co-workers investigated the application of molecular or short-path distiUation in the enrichment of the lithium isotopes. They developed single and multi-stage apparatus and found separation factors between 1.052 and 1.064 for one stage in the temperature range from 535 to 627 °C. In a similar way the mercury isotopes were separated. 

Gunning, Pertel, and their coworkers reported the photochemical separation of mercury isotopes [92-95] in a flow reactor which consisted of a microwave-operated discharge lamp [52, 96] cooled by a flowing film of water. A filter cell and a circulation system, to prevent heating of the filter solution and the cell, were placed concentrically and coaxially with the lamp. A similar reactor, for small-scale laboratory photolysis of organic compounds in the solution or gas phase, has been proposed by Den Besten and Tracy [91]. In this arrangement the EDL was placed in a reaction solution and was operated by means of an external microwave field from a radio or microwave-frequency transmitter (Fig. 19.11). The quantum output of the lamp was controlled by changing the output of the trans-... 

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