The gas-chromatographic determination of residues of barban and its major metabolites in crops

Abstract

A method is described for the determination of residues of barban [4-chlorobut-2-ynyl N-(3-chlorophenyl)carbamate] and its major water-soluble metabolites in harvest grain (wheat and barley) and sugar beet. Hydrolysis of barban and its metabolites yields 3-chloroaniline. Bromine water quantitatively converts 3-chloroaniline into its tribromo derivative, which can be detected by electron-capture gas chromatography. The limit of detection is 0·01 p.p.m. of barban. Mean recoveries of barban added to sugar beet, wheat and barley samples are 84·0, 68·8 and 78·0 per cent., respectively. The possibility of interference from other herbicides is discussed.

The method is more rapid than other published procedures and allows smaller samples to be extracted without loss of sensitivity.