Abstract :
GC/ECNI-MS in both the full scan and selected ion monitoring modes was applied to study the patterns of brominated compounds in the blubber of marine mammals from a variety of locations. The adipose tissue of one polar bear was also studied. Occurrence of three major residues originating from the use of brominated flameretardants (PBDE 47, 99, and 100) and several potential naturally occurring brominated compounds was studied in the samples. A series of three major natural brominated compounds (BC-1, BC-2, BC-3) recently identified in dolphins from Australia was included in this study. Two further brominated compounds, BC-10 and BC-I I, were studied for the first time. ECNI-MS full scan spectra were obtained for BC-3 and BC-10. A natural mixed halogenated compound (MHC-1) and an unknown brominated compound (UBC-1) were investigated as well. Evidence for the natural production of these secondary metabolites and their bioaccumulation in higher organisms as well as analytical protocols for their detection in the environment are presented. Some of these naturally occurring compounds may be misinterpreted as anthropogenic brominated compounds. In ECNI-MS, brominated compounds are usually identified by the detection of the fragment ions m/z 79 ([79Br]-) and m/z 81 ([81Br]-). In this work, it is shown that monitoring of additional ion traces corresponding to [Br2]- (160 type), (HBr2]- (161 type), [BrC1]- (116 type), and [HBrC1]- (117 type) fragment ions allows distinguishing between different classes of brominated compounds. This technique was used to demonstrate that UBC-1 is neither a PBDE nor a PBB congener, whereas a second mixed halogenated compound (MHC-2) was identified as a result of the ECNIMS response at m/z 114/116. Studies on blubber extracts of marine mammals from four continents resulted in the detection of significant differences in the global distribution of brominated compounds. Our results suggest that naturally occurring organobromines are more abundant than anthropogenic brominated compounds in several regions of the world.
