MICELLAR ELECTROKINETIC CHROMATOGRAPHY IN COATED CAPILLARIES - DETERMINATION OF MICELLE-AQUEOUS PARTITION-COEFFICIENTS

A micellar electrokinetic chromatography method is presented for the d etermination of the partition coefficient for the distribution nonpola r and moderately polar solutes between the micelle and the aqueous pha ses in aqueous micellar solutions. In comparison with the literature t he method is, theoretically and experimentally, the most straightforwa rd for this application. An equation is derived for the determination of the partition coefficient in a coated fused silica capillary, with negligible electroosmotic flow, from simple measurements of the migrat ion times of solutes and a marker for micelle migration. The advantage s and limitations of this method are discussed. The method is tested b y using sodium dodecylsulfate (SDS) surfactant and naphthalene, benzen e, toluene, and phenol solutes. Micellar electrokinetic chromatography in coated columns is ideally suited for the separation of hydrophobic solutes in aqueous samples.