Molecularly imprinted polymers fabricated by Pickering emulsion polymerization for the selective adsorption and separation of quercetin from Spina Gleditsiae

Abstract

In this study, novel quercetin imprinted polymers (MIPs) were constructed based on hydroxyapatite-stabilized Pickering emulsion polymerization, which were further applied for the specific recognition and selective separation of quercetin from the Spina Gleditsiae crude extract. The MIPs were synthesized via the imprinting technology by employing 4-vinyl pyridine as a functional monomer, divinyl benzene as a cross-linking agent and azodiisobutyronitrile as an initiator in the presence of quercetin. The prepared imprinted microspheres possessed a uniform spherical shape and the narrow diameter distribution of 55 μm. The batch mode adsorption experiments indicated that the adsorption capacity of the MIPs toward quercetin at 40 °C was 4.38 times that of the non-imprinted polymeric materials (NIPs) when the monomer polymerization time was 8 h. The equilibrium adsorption results fitted better with the Langmuir model, and the kinetic adsorption data provided a better fit with the pseudo-first-order model. Moreover, the adsorption capacity only decreased by 15% after five regeneration cycles. Therefore, the as-prepared MIPs were successfully used for the selective extraction of quercetin from Spina Gleditsiae. Additionally, the proposed method is simpler, and the extraction and purification of quercetin from Spina Gleditsiae can be realized in the same procedure. Hence, the novel imprinted materials provide an effective method for utilizing the active ingredient quercetin in Spina Gleditsiae.