DETERMINATION OF ORGANOCHLORINE PESTICIDE AND POLYCHLORINATED BIPHENYL RESIDUES IN FATTY FISH BY TANDEM SOLID-PHASE EXTRACTION CLEANUP

A rapid, multiresidue solid-phase extraction (SPE) technique for deter mination of organochlorine pesticide and polychlorinated biphenyl (PCB ) residues in nonfatty fish was modified for use with fatty fish, In t he modified procedures, samples are extracted with acetonitrile, and t he extract is cleaned up with both C-18 and Florisil SPE columns, Resi dues are determined by gas chromatography with electron capture detect ion. The original method was modified for use with fatty fish by reduc ing the amount of tissue extracted and by using an improved Florisil S PE cleanup, Recovery data are presented for 24 fortified organochlorin e pesticide residues (0.12 ppm) and 3 fortified PCB residues (0.80 ppm ) from flounder, bluefish, and shad samples, which contained 0.8, 5.4, and 22.6% fat, respectively. for the 3 types of fish, recoveries of 2 3 of 24 fortified organochlorine pesticide residues ranged from 55 to 129%, and recoveries of 3 fortified PCB residues ranged from 55 to 104 %, There were no significant differences in recovery based on fish spe cies and/or fat content for the majority of residues studied, This SPE method and the official AOAC method yielded comparable results for fi sh containing incurred organochlorine residues.