Comparison of three extraction and cleanup methods for determining 14C-labeled residues from wheat plants grown in soil treated with dyfonate-ring-14C

Abstract Three methods for determining organophosphorus insecticide residues in plant tissues were compared for efficiency of extraction and cleanup of 14C-labeled residues from wheat plants grown in soil treated with Dyfonatering-14C. Blending with ethyl acetate recovered 70.5% of the radioactivity present in the plant tissues and cleanup of the extract by sweep codistillation recovered 99% of the radioactivity. Blending of plants with benzene recovered about 58% of the radioactivity and subsequent cleanup of the extract on a silica gel column recovered about 78% of the activity. Although blending with acetonitrile recovered 59% of the radioactivity present in the plant tissue, partitioning of the extract between water and petroleum ether or chloroform retained only about 14 and 30% of the activity in the organic layer, respectively. Thus, the overall efficiency of this procedure was only between 8 and 18% as compared to 45 and 70% in the other 2 methods.