Details zur Publikation

Kategorie Textpublikation
Referenztyp Zeitschriften
DOI 10.1016/j.chemgeo.2017.12.008
Titel (primär) Sulfur isotope analysis by IC-MC-ICP-MS provides insight into fractionation of thioarsenates during abiotic oxidation
Autor Ullrich, M.K.; Gelman, F.; Zakon, Y.; Halicz, L.; Knöller, K.; Planer-Friedrich, B.
Journal / Serie Chemical Geology
Erscheinungsjahr 2018
Department CATHYD
Band/Volume 477
Seite von 92
Seite bis 99
Sprache englisch
Keywords Sulfide oxidation; Thio-arsenic species; Isotope ratio mass spectrometry; Thioarsenites
UFZ Querschnittsthemen RU2;
Abstract Standard sulfur isotope analysis of aqueous samples is aimed at sulfide and sulfate while often disregarding intermediate species mainly due to analytical limitations. However sulfur can form numerous intermediate species in the environment including thiometal(loid)s such as thioarsenates ([(HAsSn-IIO4 - n)-S-V](2-) n = 1-4) which can play a key role in isotope fractionation. The standard precipitation procedure for separation of sulfide and sulfate was applied to monothioarsenate solutions. Monothioarsenate was found to co-precipitate together with sulfide thus potentially impeding correct sulfide isotope analysis. To overcome the limitations associated with this standard precipitation procedure a new method was developed based on separating sulfur species by ion chromatography followed by online isotope detection on multi-collector ICP-MS (IC-MC-ICP-MS). Applying this new method fractionation between monothioarsenate and sulfate of up to - 6.1 was found during monothioarsenate oxidation. In contrast oxidation of tetrathioarsenate via tri- and di- to monothioarsenate did not result in fractionation. However the released sulfide became increasingly enriched in S-34 due to oxidation to sulfate. This process was found to introduce additional enrichment of up to 9.1 to monothioarsenate through intermolecular isotope exchange between arsenic-bound sulfur and sulfide in solution. These results help elucidate pathways of thioarsenate transformation and thus provide valuable information for the interpretation of isotope fractionation patterns in sulfidic environments.
dauerhafte UFZ-Verlinkung
Ullrich, M.K., Gelman, F., Zakon, Y., Halicz, L., Knöller, K., Planer-Friedrich, B. (2018):
Sulfur isotope analysis by IC-MC-ICP-MS provides insight into fractionation of thioarsenates during abiotic oxidation
Chem. Geol. 477 , 92 - 99