Silica-based monoliths for capillary electrochromatography: Methods of fabrication and their applications in analytical separations

This review article is intended to provide the reader with the recent advances made in the fabrication of silica-based monolithic capillary columns for use in capillary electrochromatography (CEC). The silica-based monoliths can be produced by three different approaches, namely (i) fusion of silica particles by thermal sintering, (ii) cross-linking/ entrapping silica particles in a packed bed using the sol-gel process, and (iii) polymerization of silicon alkoxide precursors using the sol-gel process. Thus far, approach (iii) is the most widely used for fabricating silica monoliths. After providing a thorough description of each of the three approaches used for the production of silica-based monolithic capillary columns, the analytical separations performed by CEC on each kind of monolith are discussed.