Sol-gel strategies for the preparation of selective materials for chemicalanalysis

The sol-gel process provides a versatile method to prepare size, shape, and charge selective materials for chemical analysis. Ion-exchange sites or fu nctionalities 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 stationar y phases with excellent thermal and hydrolytic stability can be designed to separate complex mixtures. Through variations in the sol-gel processing co nditions (silicon-to-water ratio, pH, type of silicon alkoxide), membranes with optimal porosity and/or hydrophobicity can be prepared for gas separat ion and facilitated transport applications. In this review some of the uniq ue features and new applications of sol-gel technology are described as it pertains to the development of materials with improved molecular specificit y for chemical analysis.