Analyses of polychlorinated biphenyls and chlorinated pesticides in biota:Method and quality assurance

An analytical method for polychlorinated biphenyls (PCBs) and chlorinated p esticides in mussels, fish liver, bird liver, and seal blubber is described . Different calibration functions were tested to establish the optimal fit to the nonlinear response of all included compounds. Detection limits and w ithin-batch variations were determined from standard deviations of duplicat e analyses of real samples. Within-batch, between-batch, and total relative standard deviations were calculated from regular use of control material. Percentage recovery was estimated by spiking samples with 3 selected PCB co ngeners and by spiking selected samples with all compounds included in the procedure. Quality assurance is described, covering analysis of about 450 s amples divided into 38 batches. Because between-batch variation was twice t he within-batch variation, the use of in-house control material and control charts is considered to be mandatory for this type of analyses. Use of cer tified reference material and regular participation in intercomparison exer cises have demonstrated the high quality of the method and the adequacy of the quality assurance applied.