INSTRUMENTATION
Although modern electrophoresis equipment and systems vary considerably in form and degree of automation, the essential components common to all systems (Figure) include two reservoirs (1), which contain the buffer used in the process a means of delivering current from a power supply via platinum or carbon electrodes (2), which contact the buffer, and a support medium (3) in which separation takes place connecting the two reservoirs. In some systems, wicks (4) may connect the medium to the buffer solution or directly to the electrodes. The entire apparatus is enclosed (5) to minimize evaporation and protect both the system and the operator. The direct current power supply sets the polarity of the electrodes and delivers current to the medium.
Power Supplies
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 supplies capable of providing voltages in the kilo-volt range.
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