Thermodynamics of Enantioselective Adsorption of Dipeptides on Porous-Surface Adsorbents with Grafted Antibiotics Teicoplanin and Vancomycin

The temperature effect on the retention and enantioseparation of dipeptides (DPs) with one and two chiral centers on the porous-surface adsorbents Chiral-T and Chiral-V with grafted antibiotics teicoplanin and vancomycin was studied by linear chromatography. The multidirectional dependences of the retention factor on the temperature were revealed: decreasing on Chiral-T and increasing on Chiral-V. The adsorption of DP stereoisomers is characterized by the exothermic effect on Chiral-T and endothermic effect on Chiral-V. The solvation effect and steric factors on Chiral-T have a greater influence on the retention and enantioseparation of the stereoisomers of the studied DPs than the energy changes. The thermodynamic characteristics of adsorption were analyzed using the extrathermodynamic dependences. The statistical analysis of the compensation effect revealed different mechanisms of retention and enantioseparation of the DP stereoisomers on Chiral-T and Chiral-V. The spatial configuration of the DP molecule has a greater influence on the adsorption mechanism of DP stereoisomers on Chiral-T, and the lipophilicity of DP has a greater influence on Chiral-V.