Capillary Electrochromatography:

Capillary Electrochromatography (CEC) is a hybrid separation method which couples the high separation efficiency of CZE with HPLC and uses an electric field rather than hydraulic pressure to propel the mobile phase by a packed bed. Since there is minimal backpressure, it is probable to use small-diameter packings and achieve extremely high efficiencies. Its most meaningful application appears to be in the form of on-line analyte concentration which could be used to concentrate a given sample prior to separation by CZE.

Electrochromatography, a hybrid of capillary electrophoresis and HPLC, offers a few of the best characteristic of every of the two techniques. Two types of capillary electrochromatography have been established since the early 1980s: packed column and micellar electrokinetic capillary. To date, the later has found more widespread applications.

Capillary electrochromatography appears to offer various advantages over either of the parent techniques. First, such as HPLC, it is applicable to the separation of uncharged species. Second, such as capillary electrophoresis, it gives highly efficient separations of microvolumes of sample solution without the requirement for a high- pressure pumping system. In electrochromatography, a mobile phase is transported through a stationary phase through electroosmotic-flow pumping rather than through mechanical pumping; therefore, simplifying the system significantly. Additionally, electroosmotic pumping leads to the plug flow profile rather than the hydrodynamic profile. The flat face of plug flow leads to less band broadening than the hydrodynamic profile.