Separation of basic drug substances of very similar structure using micellar electrokinetic chromatography

Small molecules having very similar molecular structure--some even with the same mass over charge--are not trivial to separate by capillary electrophoresis in free solution. However, addition of surfactants to the electrophoretic buffer and thus using the principle of micellar electrokinetic chromatography may provide separation with high resolution. The use of zwitterionic and nonionic surfactants is demonstrated and an example of how a developed system may be used for drug purity testing is given.