title: Complete elimination of interferences in the organotin determination by oxidation with dimethyldioxirane combined with alumina cleanup.
abstract: Most of the analytical procedures used in organotin (OT) speciation from sediment involves the Grignard derivatization reaction followed by a cleanup step and a desulfuration reaction since sulfur and/or sulfur species interfere with OT determination by GC/MS or GC-FPD. However, alkyl sulfides are generated from the coextracted elemental sulfur, and they are not removed by conventional desulfurization procedures. We propose here a method based on the oxidation of all the sulfur species with dimethyldioxirane (DMD) to sulfones or sulfur oxides. While sulfones are easily eliminated by alumina adsorption chromatography because they have higher polarity than OTs, the sulfur oxides are spontaneously evaporated. The DMD chemoselectivity favors the oxidation of sulfur compounds to sulfones in a few minutes, whereas OTs remain unreacted. In addition, the excess DMD is easily removed by evaporation under a nitrogen stream before the Al(2)O(3) cleanup step. The effectiveness of the desulfurization reaction combined with the cleanup step is demonstrated for a variety of sediment samples containing up to 3.1% of elemental sulfur, which is completely removed by adding 0.6 molar equiv of DMD. No statistical differences in the OT distribution pattern throughout the DMD intermediate oxidation steps were observed.
authors.affiliation: Environmental Chemistry Department and Biological Organic Chemistry Department, C.I.D.-C.S.I.C., Jordi Girona Salgado, 18-26, E-08034 Barcelona, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Fernández-Escobar
authors.forename: M
authors.initials: M
authors.lastname: Gibert
authors.forename: A
authors.initials: A
authors.lastname: Messeguer
authors.forename: J M
authors.initials: JM
authors.lastname: Bayona