Chapter 10 Separation of nucleic acids and oligonucleotides and sequencing of DNA Fragments by capillary electrophoresis

Abstract

The separation of molecules in capillary electrophoresis (CE) is based on the electrically driven flow of ions in solution. In most cases, CE exhibits greater speed and better efficiency and is easier to automate than are conventional slab-gel electrophoresis or liquid chromatography (LC). Two competing forces, electroosmotic flow (EOF) and electrophoretic mobility (μep), are involved in conventional capillary zone electrophoresis (CZE). The EOF is generated by the ionized silanol groups on the fused silica capillary and moves in the direction of the cathode. The electrophoretic mobility is dependent on both the size and the charge of the analyte. The migration time is a result of the sum of these two forces. Micellar electrokinetic capillary chromatography (MEKC) involves the addition of a surfactant such as sodium dodecyl sulfate (SDS) to the CE run buffer. This produces micelles with hydrophobic interiors and charged exteriors. Capillary gel electrophoresis (CGE) can be considered a hybrid of slab-gel electrophoresis and CE because it consists of a solid gel network covalently anchored to the capillary surface.