Determination of the gas chromatographic elution sequences of the (+)‐ and (−)‐enantiomers of stable atropisomeric PCBs on Chirasil‐dex

Abstract Pure enantiomers of chiral (atropisomeric) polychlorinated biphenyls (PCBs) obtained by high‐performance liquid chromatography were used to establish the gas chromatographic elution sequences of the (+)‐ and (−)‐enantiomers of six PCB atropisomers on Chirasil‐Dex. The elution order was found to be (−/+) for PCBs 84, 132, 136, and 176 and (+/−) for PCBs 135 and 174. The retention characteristics of all 19 tri‐ and tetra‐ ortho atropisomeric PCBs were also investigated. Nine of the atropisomers could be separated using this chiral selector. PCBs 95, 132, and 149 were completely resovled and PCBs 84, 91, 135, 136, 174, and 176 were partially separated ( R = 0.7–0.9). All of the separated congeners are 2,3,6‐substituted in at least one ring, and conversely – none of the congeners that lacks 2,3,6‐substitution could be separated. Thus, chiral recognition and enantiomer separation seems to be strongly governed by 2,3,6‐substitution.