Isolation and characterization of thiols in petroleum using Ag+-silica solid phase extraction followed by gas chromatography-mass spectrometry and high-resolution mass spectrometry

•A novel method was developed for separating thiols from crude oil.•Thiols were successfully isolated from a crude oil and a condensate oil.•The thiols are comprehensively characterized using GC–MS and high-resolution MS.•Alkyl thiols with carbon atoms ranging up to 33 were detected in the crude oil.