Collisionally-induced dissociation mass spectra of organic sulfate anions

The collisionally-induced dissociation mass spectra of a variety of organic sulfate ester anions are described and mechanistically rationalized. A cyc lic syn-elimination pathway, analogous to that of the Cope elimination, is postulated for the commonly observed formation of bisulfate anion (HSO4-, m /z 97). Deuterium labeling experiments confirm that the proton transferred to oxygen during bisulfate elimination normally originates from the C-2 pos ition, although examination of the spectra of polyfunctional steroids revea ls that the proton abstracted may originate from more distant sites as well . Adamantyl, phenyl, and vinyl sulfate anions, which do not readily lend th emselves to a cyclic syn-elimination, do not give rise to an mit 97 ion. In stead, these sulfates undergo both heterolytic and homolytic S-O bond cleav ages to yield an m/z M - 80 anion, resulting from loss of neutral SO3, as w ell as an ion at mh 80, corresponding to SO3-., respectively. Sulfates that can give rise to a resonance stabilized radical by homolytic C-O bond fiss ion, as exemplified by benzyl and linalyl sulfates, can be recognized by th e formation of an m/z 96 (SO4-.) ion.