Ion chromatographic analysis of the purity and synthesis of sulfonium and selenonium ions.

The use of single-column ion chromatography with conductometric detection was shown to be useful for the analysis of sulfonium and selenonium ions. A Hamilton PRP X-200 cation column was eluted with either solvent A (5 mM nitric acid in 30% methanol) or solvent B (4 mM nitric acid). With solvent B, trimethylsulfonium ion was separated from trimethylselenonium ion. With solvent A, amounts of trimethylsulfonium ion from 2 to 250 nmol were detected with a linear response. The retention times and response factors for a series of sulfonium ions with various organic groups were determined. In general the ions with more hydrophobic groups eluted later, but all had similar response factors. The method was shown to be useful for optimizing conditions for the synthesis of methylsulfonium ions, specifically the reaction of methyl iodide with diallyl sulfide.