DETERMINATION OF POLYCHLORINATED-BIPHENYLS IN HUMAN BLOOD-PLASMA BY ONLINE AND OFF-LINE LIQUID-CHROMATOGRAPHY - GAS-CHROMATOGRAPHY

A method for the determination of non-, mono- and di-ortho substituted polychlorinated biphenyls in human blood plasma is presented. The non -ortho CBs are isolated from the bulk of PCBs by HPLC on a dinitroanil ino-propyl silica column and collected as a heart-cut fraction that is transferred on-line to GC-MS utilizing concurrent solvent evaporation technique. The on-line coupling serves to lower the limit of determin ation and to partly automate the sample clean-up. The di- and mono-ort ho CBs are analyzed by off-line GC-ECD using two different columns. Sa mple pre-treatment is performed by extraction with organic solvents an d fractionation on silica gel. A high reproducibility and an absolute over-all recovery of approximately 70% is demonstrated. The method is applied to samples of blood from 5 individuals. All the samples demons trated a similar relative concentration profile. It was also shown tha t three CB congeners (CB 126, CB 156 and CB 170) contributed to the ma jor part of the toxic equivalent quantity of the PCB content in the bl ood.