PCB/toxaphene group separation on silica prior to congener specific determination of toxaphene residues in fish and other samples by GC/ECD.

A precise quantification of toxaphene residues of environmental samples by gas chromatography/ electron capture detection (GC/ECD) requires the separation of the bulk of the polychlorinated biphenyls (PCBs) from the compounds of technical toxaphene (CTT) fraction. For this reason, a PCB/CTT group separation on silica was developed. B8-1413 (Parlar #26) and B7-515 (Parlar #32) eluted as first and last out of ten important CTT standards, and can be used to determine the elution volume of the CTT fraction on silica. GC/ECD quantification of CTTs was possible after separation of PCBs on 8.0 g activated silica eluted with 48 mL n-hexane followed by quantitative elution of CTTs with n-hexane/toluene (65:35; v/v). This method is a compromise between separation efficiency and consumption of material. Finally, eight CTTs were quantified in cod liver samples from Iceland and the Baltic Sea.