Preparative group separation:

In a large number of biochemical preparations, desalting and exchange of buffers is an important step. Theoretically, there is no problem in achieving this separation but in actual practice, some problems may be encountered. If distilled water is being used as an eluant, tailing may be more pronounced than at higher ionic strength. Moreover, dilution is another problem. That is proposed to use volatile electrolytes like pyridinium acetate and ethylenediamine acetate. The technique is not only confined to desalting of macromolecules but it has also been extended to desalting of virus.

Gel filtration chromatography is frequently used for separation of macromolecules that have been modified chemically from the free reactant. The technique on a large scale has been used in food industry for the removal of sugars and low molecular weight contaminants from whey proteins.

Another interesting example is the removal of undesirable molecular mass contaminants.  A classic example is the removal of allergens from pharmaceutical preparations. Allergens are frequent compounds of high molecular mass that is completely excluded on the gel types that are interesting in industrial context. One example from this area is the removal of penicillinoyated proteins from penicillin. In the method of manufacture of penicillin, penicillinated proteins are created. These are highly allergenic and have to be erased.