ABSTRACT
During the 1960s, analysts who were detecting low levels of organochlorine insecticide residues in tissue samples from wild animals and birds by gas chromatography encountered a problem. Employing an electron capture detector, they often found a group of slow-running peaks that they were unable to identify. After a period of uncertainty, these peaks were found to be polychlorinated biphenyls (PCBs) (Jensen 1966). A later gas chromatogram obtained using the same detection system, but fitted with a high-resolution capillary column, is shown in Figure 13.1. It gives results obtained using extracts from biota of the Dutch Wadden Sea during the later 1980s (Boon et al. 1989).
