Extraction, cleanup, and quantitation methods for polychlorinated biphenyls (PCBs) are discussed with reference to the analysis of individual chromatographic peaks as well as total PCBs. Extraction of blood samples with hexane-saturated acetonitrile maintains the integrity of the biologically modified PCB profile and permits accurate description of pharmacokinetic parameters. Individual components are quantitated by measuring peak heights in varying concentrations of Aroclor so that residues can be reported relative to the parent mixture. Absolute quantitation of component peaks can be accomplished by using these relative values and the percentage composition of the Aroclor.