Fast chiral separation of amino acid derivatives and acidic drugs by co-electroosmotic flow capillary electrophoresis with vancomycin as chiral selector

Abstract

A fast chiral separation method for acidic enantiomers, including 9-fluorenylmethyl chloroformate (FMOC) amino acid derivatives and ketoprofen, with vancomycin as chiral selector is presented. In this method, hexadimethrine bromide (HDB), a polycationic polymer, was added to the run buffer as electroosmotic flow (EOF) modifier. The reversed EOF migrated in the same direction as the anionic analytes. Consequently, the separation time was shortened. Another advantage of using HDB as buffer additive is that the adsorption of vancomycin onto the capillary wall was minimized, hence, the separation efficiency was improved. The effects of buffer pH and vancomycin concentration on separation were investigated. Base line chiral separation of 12 FMOC-amino acid derivatives, ketoprofen and drug intermediate 4,4′-dimethoxy-5,6,5′6′-bismethylenedioxybiphenyl-2,2′-dicarboxylic acid were obtained. The separation time for each enantiomers was not more than 4.5 min, and the average efficiency of 3.2·10 5 plates/m was obtained.