Selectacel^® ion exchangers are chemical derivatives of cellulose. These ion exchangers have been shown to be particularly effective in the fractionation of a variety of high molecular weight ionic substances including serum proteins, enzymes, and nucleic acids. Their ability to perform these separations is due to their functionality and the highly hydrophilic and porous nature of the cellulose lattice. These ion exchangers possess properties that are not approached by other resin exchangers currently available. Their capacity for proteins is high, and elution may be carried out under mild conditions which prevent denaturation.