A simple and rapid gas chromatography method has been developed for
simultaneous determination of organophosphorus pesticides in vegetables.
Residues are extracted with acetone and dichloromethane. Extracts are cleaned
up by a mixed-mode solid-phase extraction column, quaternary amine and
aminopropyl silane. The pesticides are determined by gas chromatography
using a flame photometric detector. The recoveries for 9 pesticides in three
vegetables: carrot, cucumber and green mustard, fortified at 0.5 mg/kg were in
the range of 80.3% to 115.0%. Lower recoveries were obtained for
methamidophos and dimethoate. The results were compared to the method
currently used in the laboratory which does not include any cleanup
