Two kinds of enantio-selective molecularly imprinted polymers (MIP) of N-tert-butoxycarbonyl-L-tryptophan (N-Boc-L-Trp) and N-tert-butoxycarbonyl-L-tyramine (N-Boc-L-Tyr), were synthesized by photo-induced and thermal-induced polymerization, respectively, in which acrylamide (functional monomer) and ethylene glycol dimethacrylate were co-polymerized in the presence of N-Boc-L-Trp and N-Boc-L-Tyr. Thermodynamic studies on chiral separa-tion process using molecular imprinting were then carried out when the above two MIPs were employed as the stationary phase in liquid chromatography. Changes of entropy, enthalpy and Gibbs free energy in the process of imprinted-separation were analyzed. The results showed that not only the change of entropy played an important role in the separation, but also the solvation effect of the solutes and stationary phase, when a strong hydrogen-bond competitive solvent, such as isopropyl alcohol, alcohol or methanol, was sup-plemented into the mobile phase. Further studies showed that the molecular recognition of imprinted mole-cules and their enantiomorphs mainly depended on how well the geometric cavity structures of MIP suited the structure of the imprinted molecules.

Key words: molecular imprinting polymer, thermodynamics, solvation, molecular recognition