Chiral Separation of Enantiomers of a Plant Growth Regulator, Abscisic Acid, by Capillary Electrophoresis with Cyclodextrin Additives

Abstract

A capillary electrophoresis method for the chiral separation of enantiomers of a plant growth regulator—abscisic acid (ABA) was developed. Five cyclodextrins (CDs) were applied as chiral selectors and it was found that dimethyl‐β‐cyclodextrin (DM‐β‐CD), hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD), and γ‐cyclodextrin (γ‐CD) could give satisfactory enantioselectivity. The effects of concentration of the CD, pH value of the buffer, the voltage applied, and the addition of methanol on the chiral separation, were investigated. The best resolution obtained was 3.0, with a 100 mM Tris‐phosphate buffer (pH 5.90) containing 30 mM HP‐β‐CD, and an applied voltage at 15 kV. The reproducibilities of migration times and peak areas were better than 0.6% and 3.2%, respectively. The detection limit of each enantiomer of ABA was 0.30 µg/mL.