A novel surface molecularly imprinted polymer was synthesized using poly(vinyl alcohol) modified multi-walled carbon nanotubes (MWCNTs) as supporting matrix

ursolic acid (UA) as the template molecule

methacrylic acid (MAA) as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linking agent.Effect of different molar ratios of the functional monomer to the template on the performance of the synthesized MWCNTs-MIPs was discussed and the results showed that the optimum ratio was 4∶1.The multi-walled carbon nanotubes-molecularly imprinted polymers (MWCNTs-MIPs) were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).The results showed that a stable imprinted layer was grafted on the MWCNTs surface successfully.The adsorption properties were demonstrated by static adsorption and adsorption kinetic experiments.The results demonstrated that the MWCNTs-MIPs had specific selectivity for UA

yielding a maximum adsorption capacity of 53.1 mol/g and the equilibrium time took about 60 min.Solid phase extraction condition was optimized

and the optimal condition was washing with 100% methanol and eluting with 10% acetic acid methanol solution. The solid-phase extraction column packed with MWCNTs-MIPs could be applied to separate ursolic acid (UA) from similar structure oleanolic acid (OA).