Chemical Trapping and Characterization of small Oxoacids of Sulfur (SOS) and Selenium (SOSe) Generated in Aqueous Oxidations of H 2 S and H 2 Se

摘要

Small oxoacids of sulfur (SOS) are elusive molecules like sulfenic acid, HSOH, and sulfinic acid, HS(O)OH, generated by oxidation of hydro-gen sulfide, H 2 S, in aqueous solution. Like their alkyl homologs, SOS may exhibit both nucleophilic and electrophilic reactivity due to interconversion between S(II) and S(IV) tautomers. We find that SOS may be trapped in situ by derivate-ization with nucleophilic and electrophilic trapping agents and then characterized by high resolution LC/MS. Herein, we compare SOS formation from H 2 S oxidation by a variety of biologically relevant oxidants. Analogous small oxoacids of selenium, SOSe, are generated during aqueous oxidations of hydrogen selenide (H 2 Se). These SOS and SOSe species appear relatively long lived in aqueous solution, and thus may be involved in the observed physiological effects derived from H 2 S and potentially H 2 Se.