Abstract: To establish a method for the determination of five water-soluble toxicants in blood by ion chromatographymass spectrometry, including γ-hydroxybutyric acid ( GHB ), sodium fluoroacetate, sodium nitrite, glyphosate and glufosinate. An AS19 anion chromatographic column was used for separation, 50 mmol/L sodium hydroxide produced on-line was used as the eluent for isocratic elution, and the time-of-flight mass spectrometer was used as the detector. The electrospray ionization source negative ion mode and selected ion monitor mode ( selected ion monitor, SIM ) were used for analysis, and the external standard method was used for quantification. The detection of five water-soluble toxicants by ion chromatography-mass spectrometry is simple, rapid, specific and sensitive, which can provide important scientific support for judicial identification practice.