Method for determining three types of isothiazolinone preservatives in water-based glue by adopting liquid chromatography-tandem mass spectrum

The invention relates to the technical field of physical and chemical inspection of water-based glue and particularly relates to a method for determining three types of isothiazolinone preservatives in water-based glue by adopting a liquid chromatography-tandem mass spectrum. A water-based glue sample is extracted with water and centrifuged, then is subjected to LC-MS/MS analysis and is quantified by an internal standard method. The concentration range of 2-methyl-4-isothiazolin-3-ketone (MI) and 5-chloro-2-methyl-isothiazolin-3-ketone (CMI) is 2.5ng/mL-250ng/mL, the concentration range of 1,2-benzisothiazol-3(2H)-ketone (BIT) is 5ng/mL-500ng/mL, the linear relation is good (R2 is more than or equal to 0.9996), the adding standard recovery rates of three adding levels are 96.3%-109.6%, the average relative standard deviation (RSD) is 1.5%-6.7%, and the limit of detection (LOD) and the limit of quantification (LOQ) of the method are 0.011mg/kg-0.015mg/kg and 0.035mg/kg-0.051mg/kg. The method is simple to operate, has high sensitivity and good repeatability, and is suitable for rapidly determining MI, CMI and BIT in the water-based glue.