Additive Concentration Effects on Enantioselective Separations in Supercritical Fluid Chromatography
Karen W. Phinney, Lane C. Sander
Polar additive concentration effects in supercritical fluid chromatography were studied on two chiral stationary phases, Chirobiotic V and Chiralpak AD. Two basic additives, isopropylamine and triethylamine, were incorporated into the methanol modifier at various concentrations, and the effects on retention selectivity, and resolution were monitored. Many of the analytes failed to elute from the Chirobiotic V CSP in the absence of an additive, and the most noticeable effect of increasing additive concentration was a significant decrease in retention. On the Chiralpak AD CSP, the additives had little effect on retention, but they did foster significant improvements in peak shape and resolution.