Characteristics of gel:

The two classes of gels are macroreticular and microreticular. In macroreticular gels, the microstructure is extremely heterogenous with regions where gel material is aggregated and regions where there is very little gel matrix. The regions free from gel matrix allow large molecules to enter. In the microreticular structure, the gel matrix is relatively distributed throughout the gel. They fractionate associatively lower molecular mass ranges than the macroreticular gels. A microreticular gels are supposed to be mechanically weaker than macroreticular gels.

 The subsequent are the important characteristics for a gel to be useful for chromatographic work:

i)          Matrix of gel should be inert.

ii)        Gel must be chemically stable.

iii)       That should have low content of ionic groups.

iv)       There should be a huge choice of availablility of gels with similar general composition but different fractionational ranges.

v)         The gels should be available along with different particle size.

vi)       The mechanical rigidity of the gel should be as high as possible.