Determination of methyl bromide traces in some food products by HS-GC/MS

A simple and rapid method has been developed for fast selective determination of residues of methyl bromide in food products. The method is based on the use of a GC/MS computer-aided system equipped with a headspace. Analysis of methyl bromide was carried out directly on the food products without preliminary extraction of fumigant. An MSD quadrupole mass spectrometer with data processing allowed rapid identification of the separated volatile compound in the samples. The technique of focusing on characteristic single ion monitoring for quantification of methyl bromide, compared with chromatographic peak area measurement, turned out to have a good degree of accuracy and sensitivity. The use of known amount of added methyl bromide allowed better evaluation of traces of this compound. The proposed method was applied to the analysis of methyl bromide residues in alimentary pastes, white flour, rice, hazelnuts, peanuts and dried mushrooms (boletus).