The liquid chromatography-tandem mass spectrometry method was used to analyze aldicarb sulfone, aldicarb sulfoxide, 3-hydroxycarbofuran, phorate sulfone, phorate sulfoxide, fluocarbonitrile, fipronil sulfone, and Qualitative determination of fipronil thioether. Liquid chromatography was used to analyze aldicarb sulfone, aldicarb sulfoxide, 3-hydroxycarbofuran, phorate sulfone, phorate sulfoxide, fluocarbonitrile, fipronil sulfone, and fipronil in pesticide products. Quantitative determination of thioethers.