Determination of chlorpyrifos and its metabolite in vegetables using gas chromatography-tandem mass spectrometry

A method was developed for the determination of chlorpyrifos and its metabolite-3,5,6-trichloro-2-pyridinol (TCP) in vegetables using gas chromatography-tandem mass spectrometry (GC-MS/MS). The sample was extracted with acetone. After the concentration, TCP was derivatized with N-(tert-butyldimethylsilyl) -N-methyltrifluoroacetamide (MTBSTFA). The purification was performed using a florisil solid-phase extraction cartridge. The analyte was detected by triple quadrupole MS in multi-reaction monitoring mode. An internal standard method was used for the quantification of chlorpyrifos, the limit of quantification was 1 mu g/kg, and the recoveries were in the range of 75.57% - 106.41% with the relative standard deviations (RSDs) of 8.33% - 17.58%. An external standard method was used for the quantification of TCP, the limit of quantification was 0.5 mu g/kg, and the recoveries were in the range of 69.11% - 108.43% with the RSDs of 5.20% - 19.42%. The good linear relationships were obtained in the range of 2 - 100 mu g/L for the both target analytes. The method can be applied for the determination of chlorpyrifos and its metabolite in vegetables.