Rapid gas chromatographic method for the multiresidue screening of fruits and vegetables for organochlorine and organophosphate pesticides.

A rapid and reliable method was developed for the determination of pesticides in fruits and vegetables. A 100 g sample is extracted with a mixture of 200 mL petroleum ether and 100 mL 2-propanol. The extract is backwashed 4 times, twice with aqueous sodium sulfate and twice with 350 mL distilled water, and then dried over 15 g sodium sulfate. The dried extract is analyzed by capillary gas chromatography with selective organochlorine and organophosphorus detection. The method determines primarily nonpolar pesticides, with recoveries ranging from 81 to 114%, and has an average limit of detection of 10 ppb for both detectors.