METABOLITE OF POLYBROMINATED BIPHENYLS - ITS IDENTIFICATION AND DECOMPOSITION TO A BROMINATED DIBENZOFURAN IN THE GAS CHROMATOGRAPH MASS SPECTROMETER

The feces of dogs fed Firemaster BP-6, a mixture of polybrominated biphenyls, contained a metabolite identified as 6-hydroxy-2, 4, 5, 2ʹ,4ʹ,5ʹ-hexabromobiphenyl (hydroxy-HBB). Mass spectrometry (MS), thin-layer chromatography (TLC), and gas chromatography (GC) were used to compare the metabolite and synthetic hydroxy-HBB. The substitution pattern of the synthetic hydroxy-HBB was determined by comparing its nuclear magnetic resonance spectrum with that of 2, 4, 5, 2ʹ,4ʹ,5ʹ-HBB. MS analysis showed that, during GC on OV-lOl columns at 230 to 260 °C, hydroxy-HBB unexpectedly decomposed into two pentabromodibenzofurans (PDBF). The hydroxy compound could be differentiated from the PDBF artifacts by TLC, infrared spectroscopy, formation of an acetate derivative, and MS analysis, using direct probe insertion into the source. Similar tests should be used to corroborate GC-MS data that indicate the presence of brominated dibenzofurans as contaminants or metabolites. © 1979, American Chemical Society. All rights reserved.