Sol-gel strategies for the preparation of selective materials for chemical analysis

The sol-gel process provides a versatile method to prepare size, shape, and charge selective materials for chemical analysis. Ion-exchange sites or functionalities can be introduced into the inorganic framework as a means to preconcentrate an appropriately charged analyte into a film for detection. Template-based approaches can be utilized to design porous inorganic hosts with improved molecular recognition capabilities. Chromatographic stationary phases with excellent thermal and hydrolytic stability can be designed to separate complex mixtures. Through variations in the sol-gel processing conditions (silicon-to-water ratio, pH, type of silicon alkoxide), membranes with optimal porosity and/or hydrophobicity can be prepared for gas separation and facilitated transport applications. In this review some of the unique features and new applications of sol-gel technology are described as it pertains to the development of materials with improved molecular specificity for chemical analysis.