Enhancing sensitivity in capillary electrophoresis

Capillary electrophoresis (CE) provides an efficient separation methodology for a wide variety of chemical components in diverse matrices. However, the concentration-sensitivity of CE is usually much lower than that of liquid chromatography (LC) and inadequate for many practical applications. In recent years, this shortcoming has been addressed by developing various approaches to enhance the sensitivity of CE, and these are the subject of this article. They involve either the use of improved detection systems or the development of automatic pre-concentration methodologies for both on-capillary and on-line coupled systems. This article discusses recently reported detection modes based on the use on non-absorbance detectors and chemiluminescence and derivatization reactions. Also, it reviews sensitivity enhancements based on on-capillary and on-line coupled pre-concentration techniques. By virtue of such valuable features as low cost, flexibility, miniaturization and ease of use, continuous-flow systems coupled to CE equipment using a UV/Vis detector are shown to be especially suitable for routine use. (C) 2003 Elsevier Ltd. All rights reserved.