Determination of Six Organophosphrous Pesticide Residues in Vegetables Using QuEChERS Purification Coupled with Gas Chromatography

A method of QuEChERS(Quick, Easy, Cheap, Effective, Rugged and Safe) sample preparation coupled with gas chromatography has been established for the determination of six organophosphrous pesticide residues in vegetables. The samples were extracted with acetonitrile and cleaned up by dispersive solid phase extraction using N-propyl ethylenediamine(PSA) and magnesium sulfate as sorbents, then determined on a gas chromatograph with a flame photometric detector(FPD). Two different extraction systems of sodium chloride precipitation and acetate buffer for the method of QuEChERS were studied, and the results show that organophosphorus pesticide residues were more stable and with higher recoveries in the acetate buffer extraction system. Six organophosphorus pesticide residues, in the range of 0.2~10.0 mg/L had a good linear relationship, with correlation coefficients more than 0.999. The limits of detection were in the range of 0.003 5~0.015 mg/kg. The recoveries of six organophosphorus pesticide residues in various spiked levels ranged from 78.5% to 106.3%, with RSDs of 1.4%~6.3%. The method showed the advantages of simplicity, rapidity and reliability and meet the demands of the determination pesticide residues for batch samples.