Chiroptical Detection after Liquid Chromatography 2: Enantiomerization during HPLC on an optically active sorbent. Deconvolution of experimental chromatograms

The enantiomers of 1,3,7-trimethylbenzo[c]phenanthrene, a chiral helicene hydrocarbon, are separated on triacetyl-cellulose but interconvert during HPLC. Column temperatures were between 2 and 22°C and linear velocities between 0.3 and 1.2 mm s–1. Simultaneous photometric and polarimetric detection resulted in deconvoluted experimental chromatograms, showing the relative concentration of each of the enantiomers as aseparate function of the retention volume. The use of deconvoluted chromatograms for determining rate constants of enantiomerization is discussed. It is of interest that the rate constant at 22.3°C in solution, i.e. in the absence of a sorbent, has been obtained by an independent method: stopped-flow monitoring of racemization after HPLC on triacetylcellulose