Capillary electrochromatography (CEC) is a separation technique that shares attributes of liquid chromatography and capillary zone electrophoresis. Currently developmental, it has promise for use in separations of multicomponent mixtures in complex matrices such as soils, ground and surface waters, food products, and biological samples. Like capillary zone electrophoresis (CZE), capillary electrochromatography is an efficient technique—that is, it produces a high number of theoretical plates per separation. Like high-performance liquid chromatography (HPLC), capillary electrochromatography is highly selective—it enables differential retention of one analyte over another.