Preparative fractionation:

To a huge extent, this method has been used as a tool for separating the proteins, their degradation products and their complexes.

Isolation of antibodies to specific antigens is a subject of great interest. The separation of an antibody from the antigens can be performed by gel filtration chromatography. Fractionation of nucleic acids and animal viruses has also been attained on agar gels.

An important industrial example based on fractionation by gel filtration chromatography is the preparation of tetanus toxoid for immunization purposes. In order to make the extremely toxic tetanospasmin harmless so that it can be injected, it is polymerized through treatment along with formalin. The polymer (toxoid) is separated from the monomer by gel filtration chromatography on column packed with Sephadex G-100.

The examples of applications cited in the foregoing discussion pertain exclusively to size exclusion chromatography. But there are many areas where the gels used for size exclusion chromatography have applications in other areas of separations.

The details of their applications are given in the respective Units. However, a brief account of these is being given below under miscellaneous applications.