SELECTIVE ION EXCHANGE MEDIA

摘要

An ion exchange resin having functional groups of the formula :- wherein :- A and B, independently of each other, represent groups forming together with the attached carbon and nitrogen atoms, an optionally substituted five or six membered heterocyclic ring which may embody a further heteroatom and wherein at least one of such heterocyclic rings is an aromatic ring; R* may be totally absent or it may represent an optionally substituted alkyl radical and Z represents a resin to which the functional groups are attached.