Characterization of an abundant and novel methyl- and methoxy-substituted brominated diphenyl ether isolated from whale blubber

A previously unidentified yet abundant substituted polybrominated diphenyl ether (PBDE) was isolated from a northern bottlenose whale (Hyperoodon ampullatus) found dead in the Skagerrak, North Sea. A combination of gas chromatography, high and low resolution mass spectrometry and nuclear magnetic resonance spectroscopy (NMR) (1H, 1H–1H and 1H–13C) after isolation with preparative capillary gas chromatography (PCGC) lead to the identification of the unknown substance as 6-MeO-5-Me-2,2′,3,4′-tetrabromo diphenyl ether (6-MeO-5-Me-BDE42). To our knowledge this is only the second time PCGC has been used to isolate individual organohalogen compounds present in trace amounts for identification with NMR. The concentration of this novel bioaccumulated compound was estimated to be about 100 ng g−1 lipid, which was 2.5 times higher compared with the most abundant MeO-PBDE congeners.