Investigation of the heterogeneous adsorption behavior of selected enantiomers on immobilized alpha1-acid glycoprotein.

A complete census was made of the interactions between enantiomeric solutes and the chiral protein column CHIRAL-AGP with the theory of nonlinear LC as tool. The surface is heterogeneous, having a small number of strong enantioselective adsorption sites and a large number of weak nonselective ones. When the eluent pH was increased, the "linear" retention of (i) the amines increased strongly as a result of a strong increase in the enantioselective binding strength, whereas (ii) the retention of the aprot increased slightly as a result of an increase in both the enantioselective binding strength and its capacity. The retention of (iii) the acid has a maximum originating solely from the enantioselective binding energy, whereas the nonselective equilibria decreased steadily. For all compounds, the enantioselective equilibrium constants increase relatively more than the nonselective ones with increasing pH.