Preparation and Evaluation of C18 Modified Capillary Open-Tubular Column Based on Thiol-ene Click Chemistry for Capillary Electrochromatography

Abstract

Abstract A novel C 18 open-tubular column (C 18 capillary) for capillary electrochromatography was prepared based on thiol-ene click chemistry between n -octadecanethiol and vinyl-functionalized capillary (vinyl capillary). The inner wall of capillary was chemically modified with vinyltrimethoxysilane to provide ene-functionality. Then n -octadecanethiol was chemically bonded on the surface of vinyl capillary via thiol-ene click chemistry. The surface features of the prepared C 18 capillary was investigated using scanning electron microscopy. The effects of buffer pH on the electroosmotic flow of C 18 capillary, vinyl capillary was compared with bare capillary. The experiment results indicated that the lowest EOF profile was obtained on the C 18 capillary under the same experimental conditions compared with vinyl capillary and bare capillary. To evaluate the column performance, test mixture of three polycyclic aromatic hydrocarbons (PAHs) were electrochromatographic separation on C 18 capillary, vinyl capillary and bare capillary. The electrochromatographic retention behavior of the selected model PAHs on C 18 capillary was also investigated. The experiment results showed that C 18 capillary exhibits typical reversed-phase electrochromatographic behavior toward PAHs. Compared with vinyl capillary, the relatively good peak shape and no peak tailing was observed for the separation of basic model analytes on C 18 capillary, which may be attributed to embedded polar sulphur groups on the surface of the C 18 capillary that effectively shield the adsorption of basic analytes onto the residual silanol groups.