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 beta -cyclodextrin (s beta -CD) as the chiral additive. Bulk migration of s beta -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 s beta -CD, the crystal violet-containing buffer was reddish/purple and the crystal violet was deflected cathodically in the chamber. In the presence of s beta -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 s beta -CD to the cathodic wash solution allowed for almost complete resolution of the piperoxan enantiomers with a processing rate of 0.45 mg/h.