Micellar Liquid Chromatography: Method Development and Applications

Abstract

After more than three decades of experience, micellar liquid chromatography ( MLC ) seems to be an alternative to conventional reversed phase liquid chromatography ( RPLC ) with hydro‐organic mobile phases, with increasing interest in “green” chemistry. Most MLC procedures use hybrid micellar mobile phases containing a surfactant (frequently sodium dodecyl sulfate) above the critical micellar concentration and a relatively small amount of organic solvent to increase the elution strength and improve the efficiencies. Practical indications a chromatographer should consider in MLC when developing an analytical procedure, related to the mobile‐phase preparation and the cautions with the stationary phase, are discussed. The retention models to be considered for optimizing the best experimental conditions, taking the concentrations of surfactant and organic solvent and the pH as factors, and the diverse detection modes that have been used in MLC are described. The direct injection capability of MLC after simple filtration is highlighted. A compilation of analytical methods in MLC is given, mainly related to the determination of drugs in formulations and physiological fluids, oriented to follow the parent drug and/or its metabolites.