[The quantification of toxaphene residues in fish oils]

When quantified by HPGC-ECD and HPGC-NCI-SIM commercially available standards of the insecticide Toxaphene show different detector responses, primarily depending on the percentage of chlorine in the mixtures. To obtain accurate results, residues of Toxaphene in environmental samples should be quantified by using a standard with a similar or nearly similar detector response. If this is not possible, any standard may be used but the results of the samples must be corrected afterwards. By comparing different integration methods, it can be seen that the best results are obtained by integrating as many single-peak areas as possible. Quantification by integration of the bulge formed by raising the baseline, which can be observed in many gas chromatograms of Toxaphene standards, should be avoided because this hump is caused by degradation of chlorobornanes under higher temperatures. The extent of this bulge depends both on temperature and the percentage of chlorine, the latter being generally lower in the samples as a result of transformation processes under environmental conditions. Therefore integration of the bulge or the whole area leads to lower results.