Dimethylaminoethyl methacrylate (DMAEMA) was grafted on micron-sized silica gel particles in a manner of “graft from” in a solution polymerization system by right of the mediation action of the coupling agent 3-methacryloxypropyl trimethoxysilane (MPS), obtaining the grafted functional particles PDMAEMA/SiO₂. Then, the molecular imprinting towards the grafted PDMAEMA was performed with L-Asp that is one enantiomer of aspartic acid (Asp) as template molecule and dichloroether as crosslinking agent by using the novel surface-molecular imprinting technique established by our research group, and the L-Asp molecule-imprinted material MIP-PDMAEMA/SiO₂ was prepared. Both static and dynamic methods were adopted to study the recognition property of MIP-PDMAEMA/SiO₂ particles for L-Asp with respect to another enantiomer of aspartic acid, D-Asp, and the separation ability towards L-Asp and D-Asp in the raceme. The experiment results show that MIP-PDMAEMA/SiO₂ particles possess obvious recognition selectivity and fine binding affinity for L-Asp, and the selectivity coefficient is equal to 3.24. Besides, MIP-PDMAEMA/SiO₂ particles have excellent elution property, and with a diluted aqueous solution of NaOH as the eluent, the desorption ratios of L-Asp reach 99.73% in 13 BV.

Key words: aspartic acid, enantiomer separation, sueface-molecular imprinting, dimethylaminoethyl methacrylate, graft polymerization, molecular recognition