Abstract: A method was developed to simultaneously analyze the contents of five bactericides including 2-methyl-4-isothiazoline-3-one (MI), 5-chloro-2-methyl-3(2H)-isothiazolone (CMI), 1,2-benzisothiazolin-3-one (BIT), pentachlorophenol (PCP) and bronopol, in food contact paper and wood products using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Samples were extracted ultrasonically with methanol. The analytes were separated on an Eclipse Plus column C18 (4.6 mm × 100 mm, 3.5 μm) with methanol-water as the mobile phase. The multiple reaction monitoring (MRM) mode was applied to qualitatively analyze the five bactericides with a positive or negative electrospray ionization source according to their retention times and characteristic structures. The external standard method was used for quantitative analysis. The results showed that the linear ranges of the five bactericides were from 1 to 100 μg/L, and the limit of detection (LOD) of the method (RSN = 3) was in the range from 2.7 to 47 μg/kg. The mean recoveries for paper and wood samples at spiked concentration levels of 8 to 500 μg/kg ranged from 82.88% to 106.31%, and the precision relative standard deviations (n = 5) were 0.5%–8.1%. The method was applicable to analyze the contents of the five bactericides in food contact paper and wood products and therefore ensure food safety.

Key words: fungicide, food contact paper products, food contact wood products, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS)