Determination of organophosphate residues in aquatic product by the method of gas chromatography

Seven organophosphate residues(methamidophos,dichlorvos,acephate,dimethoate,parathion-methyl,malathion,parathion-ethyl) in aquatic product were determined by the method of gas chromatography.Organophosphate residues were first extracted from homogenized sample with acetonitrile-water assisted by n-hexane,after purification with gel filtration column,the separation and determination of organophosphate analytes were performed by the method of capillary GC and external standard calibration.Under the optimization conditions,the detection limits(S/N=10) of methamidophos,dichlorvos,acephate,dimethoate,parathion-methyl,malathion,parathion-ethyl were 0.0083,0.011,0.020,0.039,0.063,0.055 and 0.031 mg·kg-1,respectively.The standard addition recoveries of organophosphate at the level of 0.0667,0.333,1.67 mg·kg-1 ranged from 74.4% to 108%,and the relative standard derivation ranged from 2.06% to 6.98%.