Sulfoacylated poly(styrene-divinylbenzene) copolymers as resins for cation chromatography. Comparison with sulfonated, dynamically coated and silica gel cation exchangers.

Most important properties of an ion chromatographic resin are influenced by the resin matrix, the type of functional group and the ion-exchange capacity. Highly crosslinked PS-DVB resins of 5 microm diameter have been functionalized by sulfoacylation, by sulfonation and by dynamic coating over a wide range of exchange capacities. These materials allow a study of the influence of different ion-exchange sites and capacities. The influence of the degree of functionalization on resin performance is completely reverse for sulfoacylated and sulfonated resins. The HETP values for all observed analytes (Cu, Pb, Zn, Ni, Co, Cd, Mn, Ca, Mg) in a tartaric acid elution system decrease for sulfoacylated resins with increasing capacity, for sulfonated resins with decreasing capacity. The performance of sulfoacylated exchangers is better than for dynamically coated ones and far better than for sulfonated resins. The performance of silica gel based cation-exchangers such as BioSil CAT is in most cases better than observed for sulfoacylated resins.