Constructing chiral caves and efficiently separating enantiomers of glutamic acid with novel surface-imprinting technique

Dimethylaminoethyl methacrylate (DMAEMA) was first graft-polymerized onto the surfaces of micron-sized silica gel particles in the manner of “grafting from” in a solution polymerization system, obtaining the grafted particles PDMAEMA/SiO2. Then, the molecular imprinting towards the grafted PDMAEMA was conducted with one enantiomer of glutamic acid (Glu), l-Glu, as template molecule and with 2,2′-dichlorodiethylether (DCEE) as crosslinking agent by adopting the novel surface-molecular imprinting technique established by our research group, and the single enantiomer (l-Glu) molecule-imprinted material MIP-PDMAEMA/SiO2 was obtained. With another enantiomer of glutamic acid, d-Glu, as the contrast compound, the recognition property of MIP-PDMAEMA/SiO2 for l-Glu was investigated in depth with both static and dynamic methods, and its ability to separate l-Glu and d-Glu in the racemic solution was examined. The experiment results show that the surface-imprinted material MIP-PDMAEMA/SiO2 has fine recognition selectivity and binding affinity for l-Glu, whereas its ability to combine d-Glu is poor. The selectivity coefficient of MIP-PDMAEMA/SiO2 for l-Glu with respect to d-Glu is equal to 3.30, displaying an excellent chiral separation result. It is obvious that in this study, the substance separation at the molecular configuration level has been realized successfully.