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(157) Synthesis and identification of hydroxylated PCB metabolites in human plasma. Malmberg, Tina1, Hovander, Lotta1, Athanasiadou, Maria1, Klasson Wehler, Eva2, Bergman, Åke1, 1 2 ABSTRACT- Hydroxylated PCB metabolites (OH-PCBs) are potential endocrine disturbing substances. It has been recorded that certain OH-PCBs binds to transtyretin (TTR), a transport protein, with up to ten times that of the endogenous ligand the prehormone thyroxine (T4). This affinity is probably the explanation for the observation of highly selective retention of OH-PCBs in blood from humans and wildlife. To enable risk assessment, it is important to know what compounds humans and wildlife are exposed to, and therefore, an identification of pollutants present in blood is required. The aim of this study was to identify as many as possible of the OH-PCBs retained in human blood to obtain a better picture of the total exposure of OH-PCBs. A pooled sample of human plasma was therefore analysed and compared to authentic reference standards on two different GC columns. Twenty methoxylated PCBs (MeO-PCBs) eighteen of them never synthesised before were selected and prepared for this study using traditional methods as the Cadogan diaryl coupling and the Ullman coupling. Together with previously synthesised and described MeO-PCBs a total of 60 congeners were available as reference standards. Two different fused silica columns, one polar and one non-polar were used in the GC/ECD and GC/MS (only non-polar column) modes for comparison of retention time between sample and standards. The structures of as many as 38 OH-PCB congeners were tentatively identified in the pooled human plasma sample. Key words: hydroxylated PCB, identification, human plasma, synthesis |
