An improved method for determining residues of diquat

Abstract

The ion-exchange method for determining diquat residues in potato tubers1 has been modified to give a simpler operating procedure and increased accuracy. Experiments on untreated samples with 0·08 to 0·2 p.p.m. of diquat added showed an average recovery of 76 per cent. with a standard deviation of 11 per cent. The method, with minor modifications, has been found to be generally applicable to other food crops and to water. For a 250-g sample, the limit of determination is 0·01 p.p.m.