Chiral separation of benzothiazole derivatives of amino acids using capillary zone electrophoresis

A method for the separation of enantiomers of leucine and phenylalanine benzothiazole derivatives as potential antimicrobial agents was developed using capillary zone electrophoresis with a dual cyclodextrin (CD) system. The best resolution of enantiomers was achieved in 100 mmol/L phosphate background electrolyte (pH 3.5) with the dual CD system consisting of 10 mmol/L of beta-CD with 10 mmol/L of 2-hydroxypropyl-beta-cyclodextrin for leucine derivative and 10 mmol/L of 2-hydroxypropyl-gamma-cyclodextrin for phenylalanine derivative, respectively. Under the optimal conditions, the highest enantioresolution of 1.25 was achieved in a noncoated-fused silica capillary at 17 degrees C and 24 kV applied voltage.