Compound-specific bromine isotope compositions of one natural and six industrially synthesised organobromine substances

The stable bromine isotopic composition (delta Br-81) was determined for six industrially synthesised brominated organic compounds (BOCs) and one natural BOC by gas-chromatography multi-collector inductively coupled plasma mass spectrometry (GC-mcICP-MS). The delta Br-81 compositions of brominated benzenes, phenols (both natural and industrial), anisoles, and naphthalenes were constrained with the standard differential measurement approach using as reference a monobromobenzene sample with an independently determined delta Br-81 value (-0.39 parts per thousand v. Standard Mean Ocean Bromide, SMOB). The delta Br-81 values for the industrial BOCs ranged from -4.3 to -0.4 parts per thousand. The average delta Br-81 value for the natural compound (2,4-dibromophenol) was 0.2 +/- 1.6% (1 s.d.), and for the identical industrial compound (2,4-dibromophenol) -1.1 +/- 0.9 parts per thousand (1 s.d.), with a statistically significant difference of similar to 1.4 (P<0.05). The delta Br-81 of four out of six industrial compounds was found to be significantly different from that of the natural sample. These novel results establish the bromine isotopic variability among the industrially produced BOCs in relation to a natural sample.