• Journal of Environmental Health Sciences
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• v.23 no.1
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• pp.66-73
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• 1997

This procedure describes the method for gas chromatographic determination of 31 organophosphorus and 28 organochlorine pesticides in 10g of spinach, tomato and onion. After the pesticides were extracted with several solvents, the amount of coextractives and recovery rates of acephate and methamidophos were calculated. Samples for organochlorine pesticides were cleaned up with florisil solid phase extraction columns. NaBH$_4$ was added to onion extracts, which contained sulfur compound. All the concentrated extracts were analyzed by gas chromatography with ECD and NPD. The smallest amount of coextractives resulted from the spinach samples extracted with 5% MeOH in ethyl acetate. 5% EOH in ethyl acetate had the highest extractability for acephate and methamidophos and gave the best overall performance as an extraction solvent. The ability of 5% EOH in ethyl acetate to extract various organophosphorus and organochlorine pesticides from spinach, tomato and onion was examined. Recovery of 59 insecticides ranged from 58.0% to 110.5%. The average recoveries of fortified spinach, tomato and onion were 90.08%, 94.54% and 84.90%, respectively.