A molecularly-imprinted polymer decorated on graphene oxide for the selective recognition of quercetin

A molecularly-imprinted polymer decorated on graphene oxide (GO/MIP) was designed with the aid of molecular modeling to select an appropriate functional monomer and to optimize its ratio to an imprinting molecule of quercetin (Qu) for the selective adsorption of Qu. The GO/MIP was prepared by free radical polymerization on the surface of GO using a functional monomer of 4-vinylpyridine at its optimal molar ratio to Qu of 4:1. The GO/MIP was characterized by Fourier transform infrared spectroscopy, elemental analysis, Raman spectroscopy, thermogravimetric analysis, scanning electron microscopy, atomic force microscopy and adsorption measurements. Results indicate that the equilibrium time and adsorption capacity of the GO/MIP towards Qu are 30 min and 30.61 mg g^-1 at 298 K, respectively and the adsorption data are well described by a pseudo-second-order kinetic model and the Langmuir isotherm model. From competing adsorption tests in a solution containing three flavonoids (Qu, kaempferol and rutin), the GO/MIP displays an excellent recognition ability for Qu with faster adsorption kinetics than bulk MIP without GO, and has highest adsorption capacity and selectivity for Qu among the three flavonoids, which is superior to un-imprinted polymer.