A novel approach was developed for separating petroleum aromatic sulfur-containing compounds(ASCs)using a new technique of on-column methylation combined with potassium iodide modified silica gel reduction.A solid-phase extraction column was prepared by packing diatomaceous earth loaded with silver hexafluoroantimonate,which facilitated rapid methylation of sulfur-containing compounds and enrichment of methylsulfonium salts.Subsequently,the aromatic methylsulfonium salts were efficiently reduced by potassium iodide-modified silica gel,thus obtaining ASCs of high purity.The method was validated by model compounds,and applied to treat diesel and crude oil samples.The separated fractions were analyzed by gas chromatography coupled with a sulfur chemiluminescence detector(GC-SCD)and gas chromatography-mass spectrometry(GC-MS).The analysis of model compounds demonstrates that the recovery rate of this method for dibenzothiophene compounds including shielded structures can reach 95％.Moreover,the analytical results from the petroleum samples have confirmed that the method can realize high-purity separation of various types of ASCs,and this operation is simple and quick.
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