Preparation and evaluation of enoxaparin-imprinted polymer via precipitation polymerization using microwave irradiation and conventional stirring methods

In this investigation, a series of enoxaparin-imprinted polymers were prepared, and their molecular recognition properties were assessed. Itaconic acid (ITA) was utilized as the functional monomer, while N, N′-methylenebisacrylamide (MBAA) functioned as the cross-linker, with water serving as the solvent in the synthesis of both molecularly imprinted polymers (MIPs) and non-imprinted polymers (NIPs). The MIPs were produced through precipitation polymerization, employing both microwave irradiation and conventional stirring methods. Following polymer formation, the MIPs were characterized and their adsorption capacities were evaluated. In the final stage, a method for enoxaparin sample preparation in a biological matrix —specifically, blood plasma—was developed using the MIPs. The adsorption capacity of MIPM was 43.47 ± 0.40 mg g⁻¹, exceeding that of MIPS, which was 40.77 ± 0.75 mg g⁻¹. The imprinting factors (IF) for MIPM and MIPS were 1.21 and 0.71, respectively. The evaluation of adsorption kinetics revealed that all synthesized MIPs adhered to the pseudo-second-order kinetic model, as indicated by correlation coefficients approaching one. Additionally, the adsorption isotherm analysis showed that all MIPs were consistent with the Freundlich isotherm model. BET analysis showed that MIPM exhibited the largest surface area, measuring 20.186 m²/g. The selectivity test demonstrated that MIPM possessed greater selectivity for enoxaparin compared to MIPS. The application results demonstrated that MIPM was more effective than MIPS in extracting enoxaparin from the blood plasma matrix. Using 20 mg of MIPM as the sorbent, enoxaparin was extracted from blood plasma with a recovery rate of 100.31 ± 0.21 %.