Modified gas-liquid chromatographic method for determining bromide/total bromine in foodstuffs and soils

Abstract

The widespread use of methyl bromide as a soil fumigant has necessitated the development of convenient and specific analytical methods for determining bromide/total bromine in foodstuffs and soils subsequent to fumigation. The gas-chromatographic method described by Heuser and Scudamore was initially adopted by this laboratory. However, for the substrates under investigation, i.e., salad crops and soils, we found that the method lacked resolution and reproducibility and was hindered by tailing and long retention-time peaks. The method proved suitable as a basis for development. The modified method, for dried ground substrates, is described. Mass spectrometry was used on a non-routine basis to identify the chromatogram peaks. The mean recovery for dried vegetable substrates is 97% for a wide range of bromide levels, equivalent to approximately 20–1000 mg kg^–1 on a fresh mass basis. The method can be used to determine bromide down to 0.1 mg kg^–1 of substrate fresh mass.