Comparison of aqueous and non-aqueous capillary electrochromatography for the separation of basic solutes

The analysis of basic compounds by capillary electrochromatography (CEC) on silica-based materials using conventional HPLC stationary phases has failed to address the problem of severe peak tailing and non-reproducible chromatography. Several new generation stationary phases were evaluated using aqueous and non-aqueous mobile phases. The best results were obtained in the aqueous mode using Waters Symmetry Shield RP-8, a material in which the residual silanol groups were shielded by an octylcarbamate function. For comparison, experiments were carried out using unmodified silica.