Determination of a range of organophosphorus pesticide residues in grain

Abstract

A method for the determination of a range of organophosphorus pesticides in grain has been collaboratively developed and tested. Grain is homogenised with a mixture of acetone and water and the extract partitioned with dichloromethane. The dichloromethane layer is cleaned up by chromatography on a column of charcoalsilica gel and the organophosphorus pesticides are determined by gas-liquid chromatography using a phosphorus-specific detector. The method is considered to provide an effective clean-up procedure and the mean over-all recovery of eight pesticides analysed by fourteen laboratories was 74%.