The ion kinetic energy spectra of isomeric chlorobenzenes and polychlorinated biphenyls (PCB'S)

The ion kinetic energy (IKE) spectra of the isomeric di‐and trichlorobenzenes have been examined and the data for the latter compounds suggested that there was incomplete chlorine randomization in their molecular ions in the first field‐free region of the mass spectrometer. Previous studies on the mass spectra and [metastable ion]/[daughter ion] ratios of the di‐, tetra‐ and hexachlorobiphenyls (PCB's) indicated chlorine randomization in the molecular ions of those isomers containing less than two chlorine groups ortho to the Ph‐Ph ring junction. In contrast the IKE spectra of the isomers are different and the results indicate incomplete chlorine randomization in the first field‐free region of the mass spectrometer. These spectral differences may be of some use in PCB analysis.