Sol−Gel Column Technology for Single-Step Deactivation, Coating, and Stationary-Phase Immobilization in High-Resolution Capillary Gas Chromatography

Abstract

A sol−gel chemistry-based novel approach to column technology for high-resolution capillary gas chromatography is described that effectively combines surface treatment, deactivation, coating, and stationary phase immobilization into a single step. In the conventional approach, these operations are carried out in separate steps that make column fabrication a time-consuming job. In the new approach, a cleaned fused silica capillary is filled with a sol solution of appropriate composition, and sol−gel reactions are allowed to go on inside the capillary for a controlled period, typically 15−60 min. A wall-bonded coating results due to condensation of the surface silanol groups with the sol−gel network evolving in their vicinity. Because of the direct chemical bonding to fused silica substrates, sol−gel coatings possess significantly higher thermal stability than conventional coatings. This is especially important for thick and/or polar stationary phase coatings that are difficult to immobilize. Scanning elect...