Ethylene dibromide residues in biscuits and commercial flour.

Flour and biscuit samples from a school lunch program were analyzed for ethylene dibromide (EDB). Flour samples were extracted with hexane at room temperature with maximum extraction of EDB in 4 days. Biscuits were extracted by steam distillation with hexane; optimum recoveries were obtained by a triple extraction of the sample. Recoveries of EDB from flour and biscuits ranged from 85 to 103% as determined by gas-liquid chromatography on a 15% OV-17 column and a 63Ni electron capture detector. Random samples were confirmed by gas chromatography-mass spectrometry. From less than 8 ppb to 4 ppm EDB were determined in flour and less than 0.5 ppb to 260 ppb in biscuits. Possible sources for the higher values are discussed.