What are the modes of operation in capillary electrophoresis?

There are several modes of operation in capillary electrophoresis. 

1. Capillary zone electrophoresis: This technique is used for analyzing peptide mixtures and protein digests. It is efficient in separating components, has minimal sample volume requirements, and provides quick analysis times. 
2. Capillary isoelectric focusing (CIEF): Involves a mode of CE enabling the separation of proteins based on their isoelectric points. 
3. Capillary gel electrophoresis: Utilizing high voltage for effective separations. 
4. Capillary isotachophoresis: This utilizes high voltage for efficient separations. 
5. Micellar electrokinetic capillary chromatography (MEKC): Combines electrophoresis and chromatography. It is carried out in an electrolytic solution containing a surfactant above its critical micellar concentration (CMC). 
6. Capillary electrochemotherapy (CEC): Achieves separation through a packed column resembling chromatography. The liquid mobile phase flows over the silica wall and particles; an electroosmotic flow is generated due to charges present on the surface.