Study on improvement of chiral separation of capillary electrophoresis based on cyclodextrin by deep eutectic solvents

Abstract

For the first time, the mechanism of deep eutectic solvents (DESs) improving chiral separation by capillary electrophoresis has been studied. The capillary electrophoresis chiral separation has been improved by using DESs as the auxiliary additive. Taking tropicamide, homatropine hydrochloride, ofloxacin, atenolol and propranolol hydrochloride as model chiral separation targets and cyclodextrin (CD) as the chiral selector, and the effects of DESs on the chiral separation resolution were investigated on the basis of optimized conditions. The results of fluorescence spectrophotometry and non-aqueous capillary electrophoresis showed that DESs can improve the resolution of the enantiomers, and the coordination mechanism of DESs was also explored. After DESs were added, the resolution of the above enantiomers increased from 1.26, 1.70, 5.10, 1.90, 2.02 to 3.02, 4.10, 6.86, 2.84 and 5.51 respectively, and the binding constant of CD with propranolol hydrochloride increased from 23 M−1 to 142 M−1. The results showed that DESs is an effective auxiliary additive to improve the separation efficiency of capillary electrophoresis with CD as a basic chiral additive.