A CONGENER-SPECIFIC METHOD FOR THE QUANTIFICATION OF CAMPHECHLOR (TOXAPHENE) RESIDUES IN FISH AND OTHER FOODSTUFFS

To develop a method for the quantification of camphechlor without the use of complex technical toxaphene as gas-chromatographic standard, al l important chlorobornane peaks have been identified in a mixed marine fish sample reflecting the fish consumption in Germany. Further ECD b ut not ECNI-MS has been found to be suitable for estimation of the rel ative concentrations of chlorobornanes. The three camphechlor congener s with the highest ECD response have been found in concentrations of 0 .05-0.08 mg/kg (fat basis), representing about 50% of the total chloro bornanes present. A predominance of these congeners has also been obse rved in a standard reference material of cod liver oil (SRM 1588). As these three congeners are presumed to be dominant in human camphechlor intake, it is proposed to use them as indicator components for a cong ener-specific analysis of camphechlor residues together with a fourth heptachlorobornane which does not accumulate in fish. Cleanup by gel p ermeation and silica gel chromatography with GC/ECD analysis has been tested for its suitability to determine these camphechlor congeners. T he limit of determination found for each congener was about 5 mu g/kg. The determination of these four congeners allows an unambiguous ident ification without specific cleanup (e.g. complete separation from PCBs or chlordanes) and a simple quantification of camphechlor residues, t hus eliminating systematic errors resulting from different technical s tandards or detectors.