Fumigant residues in wheat and flour: solvent extraction and gas-chromatographic determination of free methyl bromide and ethylene oxide

Abstract

Methods are described for the cold solvent extraction and analysis of traces of the fumigants methyl bromide and ethylene oxide present in flour and wheat after treatment, and for determining the efficiency of extraction, in which a combination of gas-chromatographic and chemical techniques is used.

Results are given showing the loss of fumigant caused by reaction with cereal constituents before recovery, and a method for correcting this is described. Recoveries generally of 95 per cent., or more, were obtained with a lower detection limit of about 0·3 p.p.m. The application of the method to other volatile compounds is indicated.