ABSTRACT
Ligand exchange chromatography (LEC) is performed with metal ions of the soft acid type, and primarily with copper. The rate of ion exchange is limited, as a rule, by the rate at which ions and molecules can diffuse in and out of the exchanger. The exchanger used to retain the cations in LEC can be either organic or inorganic, or a combination of both, namely, a bonded silica. In the LEC, the emphasis was on the chromatography of amines, using aqueous ammonia as the eluent. Metal-loaded exchangers were shaken with aqueous solutions of thiourea, and after reaction, the thiourea remaining in the solution was measured. The partition of sugars between solutions and ion-exchange resins is governed by hydrogen bonding.
