Evaluation of a vancomycin chiral stationary phase in capillary electrochromatography using polar organic and reversed phase modes

A vancomycin chiral stationary phase (CSP) was fully evaluated in capillary electrochromatography (CEC) in reversed-phase and polar organic modes for a number of racemic pharmaceutical compounds. High efficiency and resolutio n values were obtained for a number of compound classes including thalidomi de in both the polar organic mode (190 000 plates meter(-1) and Rs = 13.8) and reversed-phase mode (125 000 plates meter(-1) and Rs = 13.0). Experimen tal parameters, including organic modifier, organic solvent ratio, ionic st rength, pH, temperature, and voltage, were examined in both the aqueous and nonaqueous modes to deduce their effect on the resultant EOF, retention ti mes, resolution, and efficiency of chiral separations. All results were con sistent with and found to be a combination of what is known from existing l iterature on CEC theory and experience obtained with macrocyclic antibiotic CSPs in LC. Column stability was excellent, and each column packed was fou nd to offer repeatable separations even when switching from the aqueous to the nonaqueous mode.