Capillary electrophoresis and related techniques on microchips have made great strides in recent years. This review concentrates on progress in capillary zone electrophoresis, but also covers other capillary techniques such as isoelectric focusing, isotachophoresis, free flow electrophoresis, and micellar electrokinetic chromatography. The material and technologies used to prepare microchips, microchip designs, channel geometries, sample manipulation and derivatization, detection, and applications of capillary electrophoresis to microchips are discussed. The progress in separation of nucleic acids and proteins is particularly emphasized.

This review article describes the preparation of dynamic and static polymeric wall coatings for capillary electrophoresis. Properties of bare fused-silica surfaces and methods for the characterization of capillary coatings are summarized. The preparation and basic properties of neutral and charged wall coatings are considered. Finally, advantages and potential applications of various coatings are discussed.

A procedure for obtaining highly stable coated capillaries for use in capillary electrophoresis (CE) is described. Reaction of surface-chlorinated fused silica capillaries with the Grignard reagent, vinyl magnesium bromide, followed by reaction of the vinyl group with acrylamide, results in an immobilized layer of polyacrylamide attached through hydrolytically stable Si-C bonds. This method is an extension of the capillary coating procedure described previously by Hjerten, differing in the means by which the polyacrylamide layer is bonded to the capillary walls. Capillaries treated in the manner described here can be used over a pH range of 2-10.5, without noticeable decomposition of the coating. In comparison to uncoated capillaries, separations of proteins using such coated capillaries are improved due to a reduction in protein adsorption to the capillary walls, although interaction is still present to some degree as evidenced by an inability to obtain plate counts as high as those predicted by theory. Electroosmotic flow is virtually eliminated in the coated capillaries, resulting in improved reproducibilities of protein migration times in comparison to uncoated capillaries. Additionally, peak skew is evaluated for model proteins and improvements are noted for the coated capillaries. Results are presented for separations of model protein mixtures, comparing the performance of the vinyl-bound polyacrylamide coated capillaries and uncoated capillaries at both high and low pH extremes.

This review article with 116 references describes recent developments in the preparation of wall coatings for capillary electrophoresis (CE) on a microchip. It deals with both dynamic and permanent coatings and concentrates on the most frequently used microchip materials including glass, poly(methyl methacrylate), poly(dimethyl siloxane), polycarbonate, and poly(ethylene terephthalate glycol). Characterization of the channel surface by measuring electroosmotic mobility and water contact angle of the surface is included as well. The utility of the microchips with coated channels is demonstrated by examples of CE separations on these chips.

This review article with 304 references describes recent developments in CE of proteins, and covers the two years since the previous review (Hutterer, K., Dolník, V., Electrophoresis 2003, 24, 3998-4012) through Spring 2005. It covers topics related to CE of proteins, including modeling of the electrophoretic migration of proteins, sample pretreatment, wall coatings, improving separation, various forms of detection, special electrophoretic techniques such as affinity CE, CIEF, and applications of CE to the analysis of proteins in real-world samples including human body fluids, food and agricultural samples, protein pharmaceuticals, and recombinant protein preparations.