Microscale High-Performance Liquid Chromatography and the Evolution of Capillary Electrochromatography
Published Online: 15 SEP 2006
Copyright © 2000 John Wiley & Sons, Ltd. All rights reserved.
Encyclopedia of Analytical Chemistry
How to Cite
Vallano, P. T., Chirica, G. S. and Remcho, V. T. 2006. Microscale High-Performance Liquid Chromatography and the Evolution of Capillary Electrochromatography. Encyclopedia of Analytical Chemistry. .
- Published Online: 15 SEP 2006
Miniaturization is a general trend in analytical chemistry. In the field of separation science, this trend has led to the development of microscale techniques based on high-performance liquid chromatography (HPLC) and electrophoresis. Two such techniques, microscale high-performance liquid chromatography (or micro LC) and capillary electrochromatography (CEC) are the subjects of this article. Micro LC is a general term that encompasses HPLC separations in which the column diameter is less than 1.0 mm. CEC is a hybrid of micro LC and capillary electrophoresis (CE). Relative to the conventional scale technique, micro LC possesses several advantages, namely higher efficiency, often shorter analysis times, reduced solvent consumption and higher mass sensitivity. Micro LC is uniquely suited for analysis of very small sample volumes (e.g. biological cells). It is this type of analysis, a formidable challenge, which has propelled the technique's continued development. CEC most commonly employs conventional HPLC particles packed into fused silica capillary columns. A potential gradient is applied along the capillary; the resulting electro-osmotic flow (EOF) then propels the mobile phase (and analytes) through the column. In CEC, the electric field (generated by a power supply) takes the place of pressure (generated by a pump) in an HPLC separation. One of the most important advantages of CEC relative to micro LC or CE is enhanced resolution. High resolution in CEC arises from the combination of high separation efficiency and selectivity inherent in the technique. CEC, however, is a relatively new technique and its ability to become a “workhorse” in the laboratory has not yet been demonstrated.