Capillary electrochromatography

High-performance liquid chromatography separates analytes by passing them, under high pressure, through a column filled with stationary phase.

Electroosmosis is the motion of liquid induced by an applied potential across a porous material, capillary tube, membrane or any other fluid conduit.

The thickness of the double layer is given by the formula: where εr is the relative permittivity of the medium, εo is the permittivity of vacuum, R is the universal gas constant, T is the absolute temperature, c is the molar concentration, and F is the Faraday constant When an electric field is applied to the fluid (usually via electrodes placed at inlets and outlets), the net charge in the electrical double layer is induced to move by the resulting Coulomb force.

Separation of components in CEC is based on interactions between the stationary phase and differential electrophoretic migration of solutes.

The analytes separate as they migrate due to their electrophoretic mobility, and are detected near the outlet end of the capillary.

Avoiding the use of pressure to introduce the mobile phase into the column, results in a number of important advantages.