ALKALI-STABLE HYDROPHILIC SORBENTS FOR ION-EXCHANGE CHROMATOGRAPHY

Ion exchangers of significantly improved quality can be obtained when base material of diol group content greater than 1 mM/g (dry weight) is used, and graft polymerization is carried out so that the degree of grafting attained is 0.5 to 2 mM/g of base material. Alkali stable hydrophilic sorbents for ion exchange chromatography are obtained through the following steps: (1) preparation of a base material (diol group content greater than 1 mM/g), e.g. crosslinked vinyl polymer from diol group containing vinyl monomers and crosslinked monomers, with polymerizable groups bonded via carbonamide group containing chains; (2) addition of the base material to an aqueous solution of the monomer to be grafted, where the monomer contains an ionic group or a precursor group for an ionic group; (3) grafting of the monomer onto the base material, where the graft polymerization is started with cerium(IV). The process parameters i.e. suspension density (base material concentration),monomer concentration, starter concentration, pH value, temperature, and addition of polymerization inhibitors are selected so that a degree of grafting of 0.5 to 2 mM/g of carrier (dry material) is attained; and (4) the precursor groups for the ionic groups in step (2) are converted to ionic groups. An independent claim is also included for the preparation of a sorbent.