GC-MS/MS Determination of Residual Amounts of Residual Amounts of Chlorpyrifos and Its Metabolite-3,5,6-Trichloro-2-Pyridinol in Fish

GC-MS/MS was applied to the simultaneous determination of residual amounts of chlorpyrifos (CP) and its metabolite 3,5,6-trichloro-2-pyridinol (TCP) in fish. The sample was extracted with a mixture of 1 mol·L-1 HCl solution and acetone (1+99). The extract was defatted by frozen at -20 ℃. After removing the fat separated, the extract was evaporated and the residue was dissolved with ethyl acetate and derivatized by reacting with N-(tert-Butyldimethylsilyl)-N-Methyltrifluoroacetamide. The derivative was purified and then analyzed by GC-MS/MS. The linearity ranges of CP and TCP were between 2.0-2 000, 1.0-1 000 μg·L-1, with the detection limits (3S/N) of 0.5, 0.3 μg·kg-1, and lower limits of determination (10S/N) of 1.7, 1.0 μg·kg-1, respectively. Values of recovery found by standard addition method were 84.6%-95.6%, 73.8%-82.7%, respectively, and RSD′s (n=6) were less than 10%, 13%, respectively.