Application of capillary electrophoresis to the determination of various benzylpenicillin salts

The application of capillary electrophoresis for separation of benzylpenicillin, procaine, benzathine and clemizole was investigated. Phosphate–borate buffer supplemented with sodium dodecyl sulphate 14.4 g/l and electrophoresis voltage 18 kV seem to provide optimal conditions for micellar electrokinetic chromatographic assay of penicillin salts. This method is selective and precise. The results obtained from CE method recovery assay (above 98% for all but procaine—97% substances) and from determination of benzylpenicillin by CE compared with HPLC results, confirmed good accuracy.