Chiral separations in reversed-phase liquid chromatography: evaluation of several polysaccharide-based chiral stationary phases for a separation strategy update.

By application of the reversed-phase generic screening conditions of a separation strategy defined in Matthijs et al. (2004) [18], the chiral discrimination abilities of six recently commercialized polysaccharide-based columns, Lux Cellulose-1, Lux Cellulose-2, Lux Cellulose-3, Lux Cellulose-4, Lux Amylose-2 and Sepapak-5, and of three classic ones, Chiralpak AD-RH, Chiralcel OD-RH and Chiralcel OJ-RH, were evaluated using a set of 58 compounds. Two mobile phases, an acidic and a basic, were sequentially applied on the columns. Using both mobile phases, a column set of Chiralcel OD-RH (or Lux Cellulose-1), Lux Cellulose-3 and Lux Amylose-2 gave the maximal number of cumulative separations, i.e. 51/58 (or 50), of which 35 (or 32) had baseline resolutions. Therefore, this set of systems was selected to update the screening step of the existing separation strategy. The selected columns were subsequently used to evaluate the applicability of the initial optimization steps, part of the existing RPLC strategy, using 66 different optimization cases. The existing optimization steps increased both the number of separations and of baseline separations by eight and by 18, respectively, relative to the screening results. Introduction of some modifications to the existing steps added eight more separations and three more baseline separations. In addition, a new optimization step for late eluting compounds was proposed and implemented. Based on these results, an updated chiral separation strategy in RPLC was defined.