Enantioseparation of chiral allenic acids by micellar electrokinetic chromatography with cyclodextrins as chiral selector

Enantioseparation of chiral aryl allenic acids by micellar electrokinetic chromatography (MEKC) with cyclodextrins (CDs) as chiral selectors was described. The screen of chiral selectors (beta-CD, gamma-CD, and hydroxypropyl (HP)-gamma-CD) showed that the enantioseparation was not only dependent on the type of CD but also the presence of 2-propanol in the buffer. In order to optimize the operational parameters, the effect of the concentration of CDs, sodium dodecyl sulfate (SDS), and 2-propanol, as well as the buffer ionic strength and pH on enantioseparation were studied. It was proved that the concentration of CDs, 2-propanol, and the buffer ionic strength were the critical parameters. Under optimal conditions, baseline separations of all seven allenic acid enantiomers were achieved. Furthermore, the method validation in terms of repeatability, linearity, limit of detection (LOD), and limit of quantitation (LOQ) were performed. Using the present method, the optical purity of a nonracemic sample with the enantiomeric excess (e.e.%) value of 99.65% was determined.