Capillary electrophoresis (CE) is a very sensitive separation method which has been developed largely through the experience acquired from high performance liquid chromatography, thin layer chromatography and from electrophoretic methods. Bio-molecules and compounds of lower molecular mass, difficult to study by HPLC or classical methods of electromigration on slab gel, become separable by CE. From now on, high performance capillary electrophoresis (HPCE), suited to automation, has replaced the traditional electrophoretic techniques on gels. CE, officially recognized by several regulatory agencies, the FDA among them, included in the pharmacopoeia, can be used for quantitative analysis. Capillary electrochromatography (CEC) is a relatively new hybrid separation method that couples the high separation efficiency of CE with HPLC.