Use of Dyes To Investigate Migration of the Chiral Selector in CFFE and the Impact on the Chiral Separations

Continuous free flow electrophoresis was investigated as a tool for the preparative chiral separation of piperoxan enantiomers using sulfated β-cyclodextrin (sβ-CD) as the chiral additive. Bulk migration of sβ-CD was confirmed using LC−MS analysis of the individual fractions collected and visualized with the addition of crystal violet to the separation buffer. In the absence of sβ-CD, the crystal violet-containing buffer was reddish/purple and the crystal violet was deflected cathodically in the chamber. In the presence of sβ-CD, the crystal violet-containing buffer was blue and was deflected anodically. However, formation of accumulation and depletion zones was apparent in both cases. The addition of sβ-CD to the cathodic wash solution allowed for almost complete resolution of the piperoxan enantiomers with a processing rate of 0.45 mg/h.