Solid Phase Extraction of Ursolic Acid Using Imprinted Polymer Modified Multi-walled Carbon Nanotubes

A novel surface-imprinted material based on multi-walled carbon nanotubes (MWNT/MIPs) modified with polyethylene glycol was successfully synthesized with a precipitation polymerization method by using ursolic acid (UA) as the template, methacrylic acid (MAA) as the functional monomer, and ethylene glycol dimethacrylate (EGDMA) as the cross-linker. The MWNT/MIPs were characterized by IR and scanning electron microscopy (SEM). The results showed that a stable, uniform imprinted material layer was grafted onto the surface of the MWNT. The adsorption capacity of the MWNT/MIPs toward UA was measured by high-performance liquid chromatography (HPLC). A maximum apparent adsorption capacity of the imprinted polymers toward UA reached up to 100.09 μmol g−1. As solid-phase extraction materials, the imprinted polymers extracted UA from actinidia chinensis planch successfully with a concentration enrichment factor of 5.35.