Sulfur isotope separation

Laser isotope separation techniques have been demonstrated for many elements, including hydrogen, boron, carbon, nitrogen, oxygen, sHicon, sulfur, chlorine, titanium, selenium, bromine, molybdenum, barium, osmium, mercury, and some of the rare-earth elements. The most significant separation involves uranium, separating uranium-235 [15117-96-1], from uranium-238 [7440-61-1], (see Uranium and uranium compounds). The... 

Sulfur isotopic data of separated pyrite as the commonest sulfide mineral (Kajiwara, 1971 Kajiwara and Date, 1971) show different values for the three sub-types of Horikoshi and Shikazono (1978). The values of pyrite in the C sub-type deposits are higher than the values of pyrite from the Y and B sub-types. The values of pyrite from the Y sub-type seem to be slightly higher than those from the B sub-type. Kajiwara and Date (1971) are of a different opinion the values from the Kosaka district are higher than those in the Hanaoka district, because all sulfur isotopic data from the C sub-type were obtained in the Kosaka district. The sulfur isotopic data on the obtained Uwamuki deposits of the B sub-type in the Hanaoka district indicate systematic decrease in 8 S passing from the yellow ore (4-7%o) to the black siliceous ore (4-5%c) (Bryndzia et al., 1983). Kajiwara and Date s data (1971) include three values of pyrite in the Doyashiki deposit of C sub-type in the Hanaoka district. The main Doyashiki... 

In the present work, twenty-seven of these oils were separately analyzed for sulfur content and sulfur isotope ratio (Parr Instrument Company bomb. Sulfate in washings from the bomb were precipitated with Ba2+. The BaSOA precipitate served for gravimetric determination of the S-content conversion to S02 for mass spectrometry (4). The 3AS/32S abundance ratios are presented in the usual 63AS notation. 

This chapter describes the chemistry of sulfur, selenium, and tellurium. Polonium will be mentioned only briefly in keeping with the fact that all of the isotopes of the element are radioactive. As a result, the chemistry of such an element is too specialized for inclusion in a survey book of this type. The plan followed in this chapter will be to discuss some of the topics of sulfur chemistry separately from those of selenium and tellurium because in several regards sulfur is somewhat different from the other two elements. 

Bioturbation and other physical processes associated with the upper portions of marine sediments may lead to rapid exchange between pore-water and overlying depositional water. Depending on the intensity of bioturbation, sulfate in depth zones 1 and 11 and the uppermost part of zone 111 (Figure 4) may be effectively in contact with an infinite reservoir of seawater sulfate. When this is the case, pore-water SO will have a nearly constant 8 value with depth regardless of the withdrawal of isotopically light sulfur to form H2S. The initial isotopic composition of H2S produced by SRB in zones 1 and 11 will be equal to the instantaneous isotopic separation between seawater sulfate and bacterial sulfide (i.e., up to about Aso -HjS = 45%o). Metastable iron sulfides and pyrite formed from this H2S will have an isotopic composition very close to this initial H2S because of the small fractionation observed during sulfidization of iron minerals. 

Figure 8.24a represents the measurement of the sulfur isotopes and " 5 in the metallothionein MT-1 fraction. As expected for the species-unspecific spiking mode, the intensity of is nearly constant over the entire electropherogram because the contribution from the metallothionein is extremely small as a result of the low natural isotopic abundance of From the measurements shown in Figure 8.24a, the isotope ratio electropherogram in Figure 8.24b was calculated. Conversion of these isotope ratios into the corresponding sulfur amounts (identical to the corresponding explanation for Figure 8.15) results in the mass flow of sulfur, and also the total sulfur amount of the separated protein (Figure 8.24c). From the known structure and known number of sulfur atoms (21) in the protein MT-1, the protein amount was calculated to be 4.69 ng of MT-1. Via simultaneous quantification of the metal ions Zn and Cd " bound in MT-1, the stoichiometry of this metallothionein could be determined as ZniCdgMT-l.

Ambartzumian, R. V., Gorokhov, Yu. A., Letokhov, V. S., and Makarov, G. N. (19756). Separation of sulfur isotopes with an enrichment ratio higher than 10 by acting on the SFe molecule with a CO2 laser radiation. Journal of Experimental and Theoretical Physics Letters, 21, 171-174. 

Two papers have been published on the speciation of sulfur using ICP-DRC/CC-MS as a detector. ICP-MS with an octopole cohision cell was used for the detection of a CE separation of metallothionein-like proteins. The collision gas (Xe) and cell conditions were selected to reduce oxygen interference ( 02+) on the main sulfur isotope A completely different approach was taken by Hann et al. who introduced O2 as the reaction gas in the collision ceU, and measured the reaction product As obtaining metal-to-sulfur ratios in... 

For SO2, pure sulfides have to be reacted with an oxidizing agent, like CuO, CU2O, V2O5 or O2. It is important to minimize the production of sulfur trioxide since there is an isotope fractionation between SO2 and SO3. Special chemical treatment is necessary if pyrite is to be analyzed separately from other sulfides. 

Fluorine is used in the separation of uranium, neptunium and plutonium isotopes by converting them into hexafluorides followed by gaseous diffusion then recovering these elements from nuclear reactors. It is used also as an oxidizer in rocket-fuel mixtures. Other applications are production of many fluo-ro compounds of commercial importance, such as sulfur hexafluoride, chlorine trifluoride and various fluorocarbons. 

The relatively intense isotope peaks separated by 2 mass units for Cl or Br provide a rapid indication of the presence of these elements in an analyte. Dichloro and dibromo compounds give similarly distinctive patterns, as shown in Figures 5.20 and 5.21. Other elements have similarly recognizable isotopic patterns, e.g. sulfur, although none is as distinctive as those for Cl and Br. 

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