PARTIAL STRUCTURE ELUCIDATION OF THE MOST ABUNDANT OCTA AND NONACHLOROTOXAPHENE CONGENERS IN MARINE MAMMALS BY USING CONVENTIONAL ELECTRON IONIZATION MASS-SPECTROMETRY AND MASS-SPECTROMETRY MASS-SPECTROMETRY

Conventional electron ionization (EI) mass spectrometry (MS) and MS/MS techniques were applied to the analysis of two abundant octa and nona chlorobornanes isolated from seals of the Baltic sea and originating f rom technical toxaphene. The exact sterical structures of the two comp ounds were previously determined using nuclear magnetic resonance (NMR ) spectroscopy by two independent research groups. The MS and MS/MS da ta generated in this study allowed partial structure elucidation of th ese polychlorobornanes, in particular revealing the distribution of th e Cl substituents between the six-membered carbon ring, the bridge and the bridgehead in the parent bornane structure. Fragmentation of the six-membered carbon ring and the bridge by retro-Diels-Alder (RDA) and related mechanisms was discovered by studying specific parent/daughte r ion transitions. The detailed fragmentation pathways formulated may be applicable to the structure elucidation of other toxaphene congener s and the monitoring of strategic transitions is highly selective for the detection of these compounds in technical toxaphene and in environ mental samples.