The proton chemical shifts of polychlorinated biphenyls

A 220 MHz NMR spectrometer has been used to identify the structure of polychlorinated biphenyls (PCBs). The proton chemical shifts and approximate coupling constants of PCBs fractionated from Aroclor 1254 are given in the text. The spectra of model compounds are included in the supplement. The chemical shifts are also tabulated according to the ring substitution pattern, when it can be seen that the shifts change systematically with the degree of both the total ring substitution and the substitution in the positions ‘ortho’ to the bridging bond between the rings.