Utilisation of the sol-gel technique for the development of novel stationary phases for capillary electrochromatography on a chip

Capillary electrochromatography (CEC) appears ideally suited for high performance separations at small scale, i.e. on a chip. Problems with the reproducible production of the required HPLC column, but also the lack of commercially available CEC instruments have prevented many putative applicants of this promising technique from entering the field. In this paper, a fast and easy way to produce self-containing open-tubular CEC columns (C8-moieties for reversed phase applications) by the sol-gel technique is described. The corresponding chips were designed to be compatible with a commercial system for capillary electrophoresis (namely a Beckman P/ACE 5500 system with diode array detection). Method development and application hence benefited from the injection and the detection options of this setup. The separation of a mixture of three uncharged analytes (polycyclic aromatic hydrocarbons) by the chip is given as example. Under optimized conditions, the performance of the chip appeared to be comparable or better than that of capillary-based CEC columns of the same kind.