Chromatographic determination of impurity binding affinities on biomineral crystals

The feasibility and utility of a chromatographic approach for evaluating crystal growth modifiers were demonstrated. Relative binding affinities of impurity molecules on calcite and calcium oxalate monohydrate crystals were dependent upon the type and number of functional groups and their stereochemistry. Equilibrium constants and adsorption energies were calculated for several molecules on calcite and were found to be in agreement with values determined using aqueous suspensions of crystalline powders. Adsorption onto calcite was found to be driven by entropic changes and likely follows an ion-exchange mechanism. A chromatographic evaluation of impurity binding affinities and thermodynamics on calcite and calcium oxalate monohydrate crystals.