Moving boundary electrophoresis

Moving Boundary Electrophoresis is a technique used in biochemistry and molecular biology for the separation of charged molecules in a solution based on their electric charge and size. This method relies on the application of an electric field across a solution, causing charged molecules to migrate towards the electrode of opposite charge at different rates, allowing for their separation and analysis.

Overview

Moving boundary electrophoresis, also known as free solution electrophoresis, is one of the earliest forms of electrophoresis. Unlike gel electrophoresis, where molecules move through a porous matrix, in moving boundary electrophoresis, molecules move in a free solution. This technique was historically significant in the development of electrophoretic methods and has been used for the study of proteins, nucleic acids, and other macromolecules.

Principle

The principle behind moving boundary electrophoresis is based on the electrophoretic mobility of ions in a solution when an electric field is applied. Molecules with a net charge will migrate towards the electrode with the opposite charge. The rate of migration is determined by the size, shape, and charge of the molecule, as well as the strength of the electric field and the properties of the solution.

Procedure

A typical moving boundary electrophoresis setup involves a U-shaped tube filled with a buffer solution. The sample is introduced into the middle of the tube, and electrodes are placed at both ends of the U-tube. When the electric field is applied, charged molecules in the sample start migrating towards the electrodes, forming distinct boundaries or zones that can be observed and analyzed.

Applications

Moving boundary electrophoresis has been used for various purposes, including:

• Determining the isoelectric point of proteins and other molecules.
• Studying the properties of proteins, such as charge and purity.
• Analyzing the composition of complex mixtures.

Limitations

While moving boundary electrophoresis has been instrumental in the development of electrophoretic techniques, it has several limitations:

• It is less commonly used today due to the development of more advanced and efficient electrophoresis methods, such as capillary electrophoresis and gel electrophoresis.
• The resolution of separation is generally lower than that achieved with gel-based methods.
• It requires careful control of solution conditions and is more susceptible to disturbances such as convection currents.

See Also

• Electrophoresis
• Capillary electrophoresis
• Gel electrophoresis
• Isoelectric focusing

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