A Stationary Phase for Open Tubular Liquid Chromatography and Electrochromatography Using Sol-Gel Technology

An organic-inorganic hybrid material was fabricated by the sol-gel method and cast as a thin glass film onto the inner walls of fused silica capillary columns. The thin film in the capillaries functioned as the stationary phase for reversed phase open tubular liquid chromatography (OTLC) and open tubular electrochromatography (OTEC). The stationary phase provides high surface area and thus an improved phase ratio. Multiple preparation steps are avoided by attaching the stationary phase and increasing the surface area in a single procedure. By adjusting the ratio of the monomeric precursors in the original sol-gel solution, the retentive characteristics of the stationary phase are controlled. This new approach facilitates column preparation for OTLC and OTEC. Capillary columns prepared in this manner showed retention characteristics superior to conventionally prepared ones. Polycyclic aromatic hydrocarbons were used to evaluate the stationary phase; under the experimental conditions used, efficiencies of 204 000-285 000 and 280 000-500 000 plates/m were observed in OTLC and OTEC, respectively. The sol-gel-derived stationary phase was shown to be stable under acidic and basic conditions.