Miscellaneous Applications:

The gels find use in thin layer chromatography using the gravity flow. As the plates in thin layer gel filtration chromatography may be difficult to dry, the chromatogram are frequent developed, whereas the liquid in the layer is transferred to paper and developed on the paper the same way as paper chromatogram. This is because the gels usually crack on drying. This type of chromatography has been used mainly for the study of proteins and peptides. Other types of fractionations that have been performed on these plates are that of nuclopolysaccharides, α -amino acids, and antibodies.

The most important application is the rapid determination of molecular masses of proteins and peptides. The technique is especially useful for this purpose as the sample can be chromatographed on the same plate as the reference substances.

Another important application of gels is in capillary gel electrophoresis which is generally performed in a porous gel polymer matrix, the pores of which contain a buffer mixture in which the separation is carried out. This type of medium could provide a molecular sieving action which retards the migration of analyte species to various degrees depending upon the pore size of the polymer and the size of the analyte ions. That is particularly helpful within separating macromolecules such as proteins, DNA fragments and oligonucleotides which have substantially similar charge but differ in size. These days most of the macroscale electrophoresis separations are carried on a gel slab. A few capillary electrophoretic separations are carried in gels holds in capillary tubes. The most general type of gel used for electrophoresis is based on polyacrylamide polymer (Bio-Gel). The other gel like agrose, methyl cellulose and polyethylene glycol has also been used for capillary gel electrophoresis.

For high performance analytical applications, little polystyrene or microporous silica particles of 5-10 µ m diameters are used. That have a pore size of a few nm to various hundred nm. The controlled pore silica particles are coated with a hydrophilic phase to reduce adsorption of the solute.