Applications of capillary electrophoresis to the clinical and pharmaceutical analysis

LUCANGIOLI S; TRIPODI V.

Capillary Electrophoresis: Fundamentals, Techniques and Applications

Ed. Nova Science Publishers, Inc.

Año: 2012; p. 187 - 209

Capillary electrophoresis (CE) is a family of related techniques that employs narrow-bore capillaries to perform high efficiency separations of both large and small molecules. These separations are favored by the use of high voltages, which may generate electroosmotic and electrophoretic flow of buffer solutions and ionic species, respectively, within the capillary. The properties of the separation and the ensuing electropherogram have characteristics resembling a cross between traditional polyacrylamide gel electrophoresis (PAGE) and modern high performance liquid chromatography (HPLC). The CE advantages with respect to other analytical techniques, such as very high resolution in short time of analysis, versatility, the possibility to analyze molecules without chromophore groups, simultaneous analysis of compounds with different hydrophobic characteristics, small volume of sample, and low cost, have made this technique adequate for the analysis of numerous types of compounds like biological macromolecules, chiral compounds, inorganic ions, organic acids, DNA fragments and even whole cells and virus particles. An increasing number of applications of CE are in progress in many clinical laboratories. Significant potential benefits in the future will impact in clinical diagnosis and therapy. Specially, there are several instances in which the limited availability of biological fluids significantly makes difficult the analysis of various relevant biochemical compounds that can be achieved by this technique because of the small volumes of sample required. In pharmaceutical quality control, it is possible to determine by CE active ingredients in the presence of related substances with different physicochemical characteristics, specially chiral impurities in the final products using the same analytical system with a relatively simple instrumental. Moreover, CE is rapidly gaining popularity thanks to the development of automated instrumentation equipped with different detectors. CE has been employed in different modes. Capillary zone electrophoresis (CZE) is the mode involving the use of a simple buffered aqueous electrolyte and the separation is based on ionic strength and pH control. Electrokinetic chromatography (EKC) is another CE mode where the mobile phase is generally an aqueous buffer and the pseudo-stationary phase is formed with micelles (MEKC), vesicles (VEKC), microdroplets (MEEKC) or polymers. The incorporation of different particles as pseudostationary phases to the electrolyte increases versatility and the selectivity of the analytical system. In summary, CE has become an important analytical tool in the field of research offering a large number of applications, as for example, the analysis of different endogenous and exogenous compounds present in biological and pharmaceutical samples, as an alternative or complementary option to traditional analytical techniques.