CE- and microchip-based separations coupled with LIF are powerful tools for the separation, detection and determination of biomolecules. CE with certain configurations has the potential to detect a small number of molecules or even a single molecule, thanks to the high spatial coherence of the laser source which permits the excitation of very small sample volumes with high efficiency. This review article discusses the use of LIF detection for the analysis of peptides and proteins in CE. The most common laser sources, basic instrumentation, derivatization modes and set-ups are briefly presented and special attention is paid to the different fluorogenic agents used for pre-, on- and postcapillary derivatization of the functional groups of these compounds. A table summarizing major applications of these derivatization reactions to the analysis of peptides and proteins in CE-LIF and a bibliography with 184 references are provided which covers papers published to the end of 2005.

Polyelectrolytes are widely used in capillary electrophoresis as coating agents of silica capillaries to prevent adsorption phenomena and improve the repeatability of peptide and protein analysis. A systematic study of the coating experimental conditions has been carried out to optimize coating stability and performance. The main experimental parameters studied were the type and concentration of polyelectrolytes used in several monolayer and multilayer coatings, the ionic strength of coating and stabilizing solutions, and the procedures used for coating and capillary storage. Electroosmotic flow magnitude, direction and repeatability were used to monitor coating stability. Coating ability to limit adsorption was investigated by monitoring variations of migration times, time-corrected peak areas and separation efficiency of test peptides. Capillary-to-capillary and batch-to-batch reproducibility was also studied. In addition, the separation performance of polyelectrolyte coatings were compared to those obtained with bare silica capillaries.

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A combination of tracer self-diffusion and NMR techniques was used to study mixed solutions of hexadecyltrimethylammonium chloride (C16TAC) and bromide (C16TAB). The degree of counterion association with the micelles, 03x), and the relative strength of counterion binding was obtained from ^Cl and 82Br self-diffusion studies. A slight increase in ¡8Br occurs at the transition from spherical to rodlike Ci6TAB micelles and is markedly greater than ß of ClgTAC solutions at all concentrations. For C16TAC/C16TAB mixtures there is a pronouncedly preferential binding of Br" ions for both spherical and rodlike micelles. For pure C16TAC or C16TAB solutions there is a marked increase in 35C1 or 81Br quadrupole relaxation on the formation of rods.For mixtures the quadrupole relaxation rate of 81Br~is strongly influenced by the presence of rodlike micelles while that of 36C1~is not. This can be interpreted either as the presence of two binding sites in the micelles with preferential Br" binding close to the head groups or as a coexistence of spheres and rods and a preferential binding of Br" to rods. For hexagonal liquid crystals of C16TAC/C16TAB mixtures, 3SC1 quadrupole splittings demonstrate a preferential binding of Br" ions.