Chromatographic resolution of a salt into its parent acid and base constituents.

Based on the results of the earlier proposed process of separation of mixtures of mineral electrolytes by size-exclusion chromatography (SEC), it has been suggested that a mineral salt must spontaneously resolve, at least partially, into its parent acid and base constituents, provided that the separating media discriminates the anion and cation of the salt according to their size. Indeed, migration of a zone of an aqueous salt solution through a bed of neutral nanoporous hypercrosslinked polystyrene-type packing was shown to result in the generation of acidic and alkaline effluent fractions. The principle of spontaneous salt resolution has been extended to other types of discriminating interactions between the stationary phase and the two ions of the salt. The idea was exemplified by the resolution of ammonium acetate, due to hydrophobic retention of the acetate, into fractions enriched in ammoniac and then acetic acid.