Identification of a novel C10H6N2Br4Cl2 heterocyclic compound in seabird eggs.: A bioaccumulating marine natural product?

A novel brominated and chlorinated compound, C10H6N2Br4Cl2, bioaccumulating in seabird eggs was identified and characterized by low- and high-resolution electron impact ionization (EI), electron capture negative ionization (ECNI), and ammonia positive chemical ionization (PCI) mass spectrometry. This compound is the major congener of a series of four hexahalogenated species. The major congener was determined in egg samples from Leach's storm; petrel, rhinoceros auklet, glaucous-winged gull, and black-footed albatross from the Pacific coast area; Leach's storm-petrel, Atlantic puffin, and herring gull from the Atlantic coast; and herring gull from the Great Lakes using GC-ECNI-MS. The concentrations of C10H6N2Br4Cl2 in the Pacific Ocean samples ranged from 1.8 to 140 ng/g (wet weight), and were significantly higher than the Atlantic Ocean samples (p = 0.037). The Pacific Ocean samples contained levels of C10H6N2Br4Cl2 approximately 1.5-2.5 times higher than in the Atlantic Ocean samples of the same or ecologically similar species. The compound was not detected in any of the samples from the Great Lakes. The Pacific Ocean offshore surface feeders had the highest concentrations (34-140 ng/g) when compared to the other samples (0.61-5.6 ng/g). Its strictly marine occurrence and relatively high nitrogen content indicate that C10H6N2Br Cl-2 probably is a marine natural product, found at highest concentrations in the Pacific Ocean surface feeding birds. A possible structure of C10H6N2Br4Cl2 is 1,1'-dimethyltetrabromoclichloro-2,2'-bipyrrole.