Resolution optimization in micellar electrokinetic chromatography: use of Plackett-Burman statistical design for the analysis of testosterone esters

Resolution in micellar electrokinetic chromatography is influenced by many factors. The optimization of the resolution of testosterone esters in a buffer with a high level of organic modifier is described. By using a Plackett-Burman design, the effects of five buffer parameters were investigated: the buffer pH, the buffer concentration, the level of organic modififer, the surfactant concentration, and the use of mixed micelles. With only eight experiments, the buffer could be optimized to give full resolution within an acceptable analysis time. The occurrence of micelles at high acetonitrile concentrations is discussed.