Determination of Organophosphorus Pesticide in Soil by Accelerated Solvent Extraction-Gas Chromagraphy/Mass Spectrometry

To develop a rapid and sensitive analytical methods for the quantitative determination of trace organophosphorus pesticides (OPPs) in soil. The target analytes, seven OPPs including dichlorvos, dimethoate, monocrotophos, methyl parathion, parathion, malathion and chlorpyrifos were extracted with the solution of acetone/dichloromethane (1:1, v/v) using accelerated solvent extraction (ASE) and then purified using gel permeation chromatography (GPC) to eliminate most of the coextracts, such as pigments and lipids. The extraction liquid were analyzed with gas chromatograph-mass spectrometry (selected ion monitoring mode). Calibration curves that were constructed for the analytes spiked into soil samples followed linear relationships with good correlation coefficients (R²>0.9960). Recoveries of seven OPPs by this procedure ranged from 84.88% to 102.11%, and the relative standard deviations varying from 2.42 to 7.81%. The detection limits were ranged from 0.009 to 0.06 ng/g. The results indicated that the obtained method is a precise, sensitive and highly efficient procedure for the determination of organophosphorus pesticides in soil.