GC Determination of 3 Organophosphorus Pesticides and Herbicide Atrazine in Soil with Accelerated Solvent Extraction

The contents of atrazine and three organophosphorus pesticides, i.e., dichlorophos, phorate and dimethoate, in soil were determined by GC. The sample was crushed and extracted statically with mixed solvent of acetone+dichloromethane (1+1) at 60 ℃ for 10 min. The Rtx-1701 column and flame photometric detector were used for separation and determination of the 3 organophosphorus pesticides; and Rtx-CLP II column and electron capture detector were used for separation and determination of atrazine. It was found that recovery of accelerated solvent extraction was better than ultrasonic extraction. Detection limits (3S/N) of the method were found 0.08 μg·kg-1 for dichlorophos, 0.07 μg·kg-1 for phorate, 0.09 μg·kg-1 for dimethoate, 0.40 μg·kg-1 for atrazine. Using blank sample of soil as matrix, test for recovery was made by standard addition method, and values of recovery obtained were in the range of 82.0%-106.0%, with values of RSD′s (n=7) in the range of 10.5%-16.9%.