Determination of organophosphorus pesticide residues in tea by solid-phase extraction-gas chromatography

A multiresidue analysis method was developed for the simultaneous determination of twenty-two organophosphorus pesticides in tea using solid-phase extraction and gas chromatographic.Tea samples were extracted with acetonitrile-acetone(4∶1,V/V) and cleane-up by Envi-Carb SPE cartridge,eluted with acetonitrile-toluene(3∶1,V/V) and determined by gas chromatography(flame photometric detector).The recoveries of those organophosphorus pesticides ranged from 81.3% to 107.9% at fortification level of 0.05～1.0 mg/kg,the relative standard deviations varied from 1.1% to 8.9%.Limits of detection were 0.01～0.04 mg/kg.The proposed method is characterized by simplicity,higher sensitivity and accuracy.