Application of the Retention Index Concept in Micellar Electrokinetic Capillary Chromatography

Abstract

The application of the retention index concept in micellar electrokinetic capillary chromatog. (MECC) was evaluated for the identification of neutral species. Homologous series of alkylbenzenes and alkylaryl ketones were applied as retention index stds. and also for the calcn. of the micelle migration time by an iteration procedure. The relation between retention indexes, I, and octanol-H2O partition coeffs. is discussed, and DI values were calcd. from retention indexes, obtained with both anionic and cationic surfactant systems, to study the sepn. mechanism for solutes with different functionalities in MECC. The influence of the phase ratio is treated theor., and the capacity factor is linearly related to the surfactant concn., whereas the retention index is independent of the surfactant concn. The temp. dependence of the retention index was studied and the std. enthalpy, entropy, and Gibbs free energy for micellar solubilization of the sample compds. were detd., showing that the hydrophobic interaction plays a significant role in MECC anal