Page 54 - Tandem Techniques

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Electrically charged compounds can be transported in a gel or liquid under the influence of an electric
field and this process has been termed electrophoresis. There are basically three different
electrophoretic methods of separation zone electrophoresis, isotachophoresis and isoelectric focusing.

Zone Electrophoresis

Zone electrophoresis is carried out in an electrolyte, across which is applied an electric field. The
samples to be separated are placed in the center of the electrolyte, which could be a electrophoretic
plate or capillary tube depending on the system being used. Those substances carrying a negative
charge migrate to the anode, while those carrying a positive charge migrate to the cathode. Eventually
the substances separate into individual bands, their relative positions depending on their individual
mobilities. This type of separation carried out in a capillary tube is the most amenable to tandem
operation. A zone electrophoretic separation is depicted, diagramatically, in Figure 1.9.

Figure 1.9
Zone Electrophoresis