Analytical response of polychlorinated biphenyl homologues and isomers in thin-layer and gas chromatography

Except for pure synthetic polychlorinated biphenyl (PCB), estimation methods of PCB by thin-layer and gas chromatography with electron capture detection give comparable results. Both give a good estimate of the true mass of a biologically modified residue, but where mostly hexachlorobiphenyls and above make up the residue, the estimate will be up to 50% too high. The Coulson detector does not, in our hands, yield comparable results with modified residues: the reason for this difference is not clear at present.