Preparation of molecularly imprinted polymers using ion-pair dummy template imprinting and polymerizable ionic liquids

Abstract

Ionic liquid based molecularly imprinted polymers have attracted considerable attention as biomimetic recognition materials due to their water-compatibility and high binding capacities. However, the selective recognition was unsatisfactory. In order to overcome this defect, we developed a novel dummy template ionic liquid based molecularly imprinted polymer, which used 1-butyl-3-vinylimidazolium α-aminohydrocinnamic acid salt as a functional monomer and the dummy template. Binding experiments showed that the obtained molecularly imprinted polymer possesses a high binding capacity (280.18 μmol g⁻¹), imprinting factor (3.17) and selectivity factor (5.75). Molecular simulation results demonstrated that the high selectivity is attributed to the formation of ion-pairs between imidazolium and L-phenylalanine, which could be located in the imprinted cavities to improve the imprinted material’s efficiency. Subsequently, the dummy template ionic liquid based imprinted polymer was employed as packing in a solid phase extraction cartridge to analyze the L-phenylalanine in the blood of a phenylketonuria patient. The results indicated that the obtained dummy template ionic liquid based imprinted polymer has good analytical performance. Thus, the dummy imprinting combined with the ionic liquid is a useful way to improve the specific recognition of ionic liquid based molecular imprinted polymers, so that this method offers promising new applications in the field of the analysis of biological samples.