Gel filtration is a simple and reliable chromatographic method for separating molecules according to size. Its versatility makes it generally applicable to the purification of all classes of biological substances, including macromolecules not readily fractionated by other techniques.
Gel filtration separations fall into two main categories, group separation and fractionation. In group separation, molecules of widely different molecular sizes are separated. A matrix is chosen such that the larger molecules, e.g. proteins, are eluted in the void volume of the column, whereas small molecules are retained in the total volume. Common examples of group separations are buffer exchange and desalting.
Fractionation is used for separation of macromolecules of different sizes. In these applications, the molecular sizes of all the components must fall within the fractionation range of the gel. Typical applications of fractionation using gel filtration are purification and molecular weight determination of proteins, peptides and nucleic acids.
In recent years, Amersham Pharmacia Biotech has introduced new media which produce unequalled resolution at higher flow rates and are more resistant to chemicals, pH and pressure.
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