Chiral Separation of Ephedrine Isomers by Capillary Electrophoresis Using Bovine Serum Albumin as a Buffer Additive

A method utilizing bovine serum albumin (BSA) as buffer additive for chiral separation by means of capillary electrophoresis is described. Parameters that affect chiral separation, such as buffer pH, buffer concentration, BSA concentration, and organic modifier, are investigated. Baseline resolution of ephedrine-pseudoephedrine and norephedrine-norpseudoephedrine isomers are achieved in an uncoated capillary with a 20 mmol/L phosphate buffer at pH 9.0 in the presence of 10 µmol/L BSA and 15% (v/v) 2-propanol at 25°C. The developed method can be applied for the analysis of ephedra plant extracts that contain the four test drugs.