Thermal sulfur isotopes

J. L. Mann and W. R. Kelly. Measurement of Sulfur Isotope Composition (834S) by Multiple-Collector Thermal Ionization Mass Spectrometry Using a 33S-36S Double Spike. Rapid Commun. Mass Spectrom., 19(2005) 3429-3441. 

Figure 19.15. The liquid thermal diffusion system for the recovery of heavy sulfur isotope in carbon disulfide. The conditions prevailing at the time after 90% 34S is reached. Each rectangle in the cascades represents a column, each height being proportional to the length of the column. The two cascades have a combined height of 14 m, annular dia 25.4 mm, and annular width 0.18-0.3 mm. Production rate of 90% concentrate of 34S was 0.3 g/day [IV. M. Rutherford, Ind. Eng. Chem. Proc. Des. Dev. 17, 17-81 (1978)].

Another procedure for sulfur isotope measurements has been developed where samples are converted to solid arsenic sulfide, AS0S3 (s), and measured by thermal ionization mass spectrometry (TIMS) (22). This technique offers several advantages over the gaseous methods in that both memory and isotope effects are eliminated, and the chemical procedure is simpler. A precision of 1 0/00, and the capability of making measurements on small samples, makes the TIMS technique competitive with gas phase MS techniques. 

Figure 11. Sulfur isotope values of sulfide minerals from selected seafloor hydro-thermal deposits. Modified from Herzig et al. (1998) with additional data from Table 1.

Experimental thermal alteration (pyrolysis) provides the best opportunity to characterize changes in type II-S kerogen under thermal stress. In the present section, we follow the changes in sulfur isotope distribution as a result of the different temperatures and pyrolysis conditions. 

In previous articles we hypothesized the existence of a high temperature back reaction of stabilized organic products with thermally activated sulfur such as S radical) (Aizenshtat et al, 1995 Krein and Aizenshtat, 1995). To experimentally evaluate this possibility we reacted, under autoclave inert conditions at 300°C, a mixture of hydrocarbons with elemental sulfur. The products and their GC/MS identification were presented in Stoler (1990). A similar experiment was performed without detailed analysis of the products distribution by Baker and Reed (1929). Most of the material polymerizes. Only 15-20% could be extracted by organic solvents (e.g. hexane or methylene chloride). The sulfur isotopes data for all products show that no isotopic discrimination occurred in this experiment (Stoler et al, 2003). All sulfur-containing isolated and identified compounds produced are thiophenes with the structure ... 

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Holloway JR, Blank JG (1994) Application of experimental results to C-O-H species in natural melts. In MR Carroll, JR Holloway (eds.) Volatiles in magmas. Rev Miner 30 187-230 Holser WT (1977) Catastrophic chemical events in the history of the ocean. Nature 267 403 08 Holser WT, Kaplan IR (1966) Isotope geochemistry of sedimentary sulfates. Chem Geol 1 93-135 Holt BD, Engelkemeier AG (1970) Thermal decomposition of barium sulfate to sulfur dioxide for mass spectrometric analysis. Anal Chem 42 1451-1453 Hoppe P, Zinner E (2000) Presolar dust grains from meteorites and their stellar sources. J Geophys Res Space Phys 105 10371-10385... 

Silver is a white, ductile metal occurring naturally in its pure form and in ores (USEPA 1980). Silver has the highest electrical and thermal conductivity of all metals. Some silver compounds are extremely photosensitive and are stable in air and water, except for tarnishing readily when exposed to sulfur compounds (Heyl et al. 1973). Metallic silver is insoluble in water, but many silver salts, such as silver nitrate, are soluble in water to more than 1220 g/L (Table 7.3). In natural environments, silver occurs primarily in the form of the sulfide or is intimately associated with other metal sulfides, especially fhose of lead, copper, iron, and gold, which are all essentially insoluble (USEPA 1980 USPHS 1990). Silver readily forms compounds with antimony, arsenic, selenium, and tellurium (Smith and Carson 1977). Silver has two stable isotopes ( ° Ag and ° Ag) and 20 radioisotopes none of the radioisotopes of silver occurs naturally, and the radioisotope with the longest physical half-life (253 days) is "° Ag. Several compounds of silver are potential explosion hazards silver oxalate decomposes explosively when heated silver acetylide (Ag2C2) is sensitive to detonation on contact and silver azide (AgN3) detonates spontaneously under certain conditions (Smith and Carson 1977). 

In a radically different analytical situation, Kelly et al. used thermal ionization and isotope dilution to determine the amount of sulfur in fossil fuels [31]. These materials (oil and coal) were to be used as reference materials for analyses by other analytical techniques the superior accuracy and precision of isotope di-... 

The " N nucleus (1 = 1, 99.6%) has a moderately large magnetic moment and hyperfine splittings from this nucleus are a distinctive feature of the ESR spectra. For example, the thermally unstable S4N4 " radical anion has been identified by its characteristic nine-line ESR spectrum. For S (/ = 3/2, 0.76%), isotopic labeling is usually necessary to obtain information on electron spin density at sulfur. 

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