Enantioselective reversed-phase and non-aqueous capillary electrochromatography using a teicoplanin chiral stationary phase

Enantiomeric separation of chiral pharmaceuticals is carried out in aqueous and non-aqueous packed capillary electrochromatography (CEC) using a teico planin chiral stationary phase (CSP). Capillaries were slurry packed with 5 mum 100-Angstrom porous silica particles modified with teicoplanin and ini tially evaluated using a non-aqueous polar organic mode system suitability test for the separation of metoprolol enantiomers (R-s = 2.3 and 53 000 pla tes m(-1)). A number of pharmaceutical drugs were subsequently screened wit h enantioselectivity obtained for 25 racemic solutes including examples of neutral, acidic and basic molecules such as coumachlor (R-s = 3.0 and 86 00 0 plates m(-1)) and alprenolol (R-s = 3.3 and 135 000 plates m(-1)) in reve rsed-phase and polar organic mode, respectively. A statistical experimental design was used to investigate the effects of non-aqueous polar organic mo bile phase parameters on the CEC electroosmotic flow, resolution and peak e fficiency for two model solutes. Results primarily indicated that higher ef ficiency and resolution values could be attained at higher methanol content s which is similar to findings obtained on this phase in liquid chromatogra phy. (C) 2000 Elsevier Science B.V. All rights reserved.