Electrophoresis (also termed cataphoresis) is the physical movement and separation of charged molecules in a solution medium under the influence of an electric field. The rate and distance of molecular movement depends upon the size, shape, and charge of the molecules subjected to the electric field, the field strength, and the conditions of the medium (e.g., electrolyte concentration, pH, ionic strength, viscosity, temperature) or gel in which the molecules move. Advances in electrophoresis have revolutionized methods of protein analysis and have found wide-ranging applications.

Swedish biochemist Arne Tiselius pioneered research in electrophoretic analysis. Tiselius was able to separate serum proteins in a tube (the Tiselius tube) subjected to an electric field.

Modern electrophoresis allows the controlled differentiation of molecules into bands or regions in differing mediums (e.g., agarose, polyacrylamide gel, paper). In addition to electrical forces, some mediums or support matrices are porous gels that can...