Electrophoresis ionic species, movement

Figure 6-9. Schematic diagram ot a two gel system and the movement of the various ionic species during electrophoresis. (From G. Bruening, R. Griddle, J. Preiss, and F. Rudert, Biochemical Experiments, Wiley, New York, 1970.)...

The power supply drives the movement of ionic species in the medium and allows adjustment and control of either the current or the voltage. In more sophisticated units, the power may be controlled as well and conditions may be programmed to change during electrophoresis. Capillary systems use power suppfies capable of providing voltages in the kilovolt range. 

Electrophoresis — Movement of charged particles (e.g., ions, colloidal particles, dispersions of suspended solid particles, emulsions of suspended immiscible liquid droplets) in an electric field. The speed depends on the size of the particle, as well as the -> viscosity, -> dielectric permittivity, and the -> ionic strength of the solution, and it is directly proportional to the applied electric field. In analytical as well as in synthetic chemistry electrophoresis has been employed to separate species based on different speeds attained in an experimental setup. In a typical setup the sample is put onto a mobile phase (dilute electrolyte solution) filled, e.g., into a capillary or soaked into a paper strip. At the ends of the strip connectors to an electrical power supply (providing voltages up to several hundred volts) are placed. Depending on their polarity and mobility the charged particles move to one of the electrodes, according to the attained speed they are sorted and separated. (See also - Tiselius, - electrophoretic effect, - zetapotential). 

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