Molecularly imprinted polymer for solid-phase extraction of oleanolic acid from Ligustrum lucidum fruit.

This article focuses on the synthesis and application of molecularly imprinted polymers (MIPs) for the selective extraction and enrichment of oleanolic acid (OA) from Ligustrum lucidum fruit. Using OA as the template molecule, acrylamide (AM) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, and azobisisobutyronitrile (AIBN) as the initiator, MIPs were prepared via bulk polymerization and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS). The MIPs demonstrated high adsorption capacity (128.32 mg/g) and were employed in a molecularly imprinted solid-phase extraction (MISPE) system, achieving a 76.0% enrichment rate of OA from crude extracts under optimized conditions. Additionally, a validated high-performance liquid chromatography (HPLC) method was established for accurate OA quantification, indicating the potential of this approach for selective separation and enrichment of OA and other triterpenoids from complex plant matrices.