Applications of Gel Exclusion Chromatography

Several experimental applications of gel chromatography have already been mentioned, but more detail will be given here. 

This is probably the most popular use of gel chromatography. Because of the ability of a gel to fractionate molecules on the basis of size, gel filtration complements other purification techniques that separate molecules on the basis of polarity and charge. 

The elution volume for a particular solute is proportional to the molecular size of that solute. This indicates that it is possible to estimate the 

Elution curve for a mixture of several proteins using gel filtration chromatography. 

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Early researchers in the application of size exclusion chromatography (SEC) to asphalt (1-7) noted that SEC (also called GPC, gel permeation chromatography) was very sensitive to differences in asphalts and to changes in composition. This was exploited by Adams and Holmgreen (8) to show differences between various asphalts and between asphalts from the same supplier at different locations. Glover et al. (9,10) used SEC to show how asphalts from a number of suppliers changed with the seasons. It has been used to compare fractions produced by preparative SEC and other methods (9,11-16). 

P.Flodin, Dextran Gels and Their Applications in Gel Filtration, Pharmacia, Uppsala, Sweden, 1962. C-S.Wu, Handbook of Size Exclusion Chromatography, M.Dekker Inc., NY, 1995. 

High performance liquid chromatography (HPLC) is rapidly increasing in its application to gel structures and organic pore systems together with the increasing use of size exclusion chromatography (SEC). 

The evolution of media covering aqueous and nonaqueous systems on the one hand and analytical as well as microscale and macroscale preparative applications on the other hand has resulted in an arbitrarily nomenclature within the field. Thus the current practice is to refer to the separation principle based on solute size as size exclusion chromatography (SEC) whereas the application in aqueous systems is traditionally referred to as gel filtration (GF) and the application in nonaqueous systems is designated gel-permeation... 

Size exclusion chromatography (SEC, also known as GPC and GFC) has become a very well accepted separation method since its introduction in the late-1950s by works of Porath and Flodin (1) and Moore (2). Polymers Standards Service (PSS) packings for SEC/SEC columns share this long-standing tradition as universal and stable sorbents for all types of polymer applications. In general, PSS SEC columns are filled with spherical, macroporous cross-linked, pressure-stable, and pH-resistant polymeric gels. 

The instrumentation of HdC, including a pump, an injector, a column (set), a detector, and a recorder or computer, is very similar to size exclusion chromatography SEC). The essence of this technique is the column. There are two types of HdC columns open microcapillary tubes and a nonporous gel-packed column. This chapter emphasizes column technology and selection and the applications of this technique on the molecular weight analysis of macromolecules. 

Many natural materials are porous but also proton-rich such as wood or other plant products. Relaxation of liquids in these materials has features in common with both inorganic matrices and the protein systems discussed above. The class of porous polysaccharide materials used for size exclusion chromatography provides an example one commercial product is Sephadex. The material swells on solvation to form a controlled pore gel. The main application involves excess liquid, generally water, which flows through the gel bed carrying solutes of various size. The large solutes are excluded from the pore interior and elute rapidly while the smaller ones equilibrate with the pore interior and elute later. The solvent generally samples the pore interior as well as the bulk phase. 

Size exclusion chromatography also known as gel filtration has been extensively used as a part of the isolation protocol of various biological molecules. This mode of application will not be considered, instead this article will concentrate on examples that use SEC as the only fractionation technique in combination with detection methods that help to give an indication of the type of molecules associated with the metal. 

The great versatility of HPLC is evidenced by the fact that all chromatographic modes, including partition, adsorption, ion exchange, chromato-focusing, and gel exclusion, are possible. In a sense, HPLC can be considered as automated liquid chromatography. The theory of each of these chromatographic modes has been discussed and needs no modification for application to HPLC. However, there are unique theoretical and practical characteristics of HPLC that should be introduced. 

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