Magnetic molecularly imprinted polymers for efficient solid-phase extraction and HPLC analysis of myricetin in pomegranate pomace

Abstract

Molecularly imprinted polymers (MIPs) show great promise for the targeted identification of active components in complex mixtures. Nevertheless, the intentional use of MIPs for the accurate extraction of bioactive phytochemicals from neglected fruit processing byproducts is a new area of exploration in sustainable biorefinery practices. In this study, a magnetic molecularly imprinted polymer (Fe₃O₄–NH₂@MIP) was synthesized utilizing a surface imprinting technique on the amino-functionalized magnetic iron trioxide (Fe₃O₄–NH₂) to improve selectivity and separation efficiency for the extraction of myricetin in pomegranate pomace. The polymerization process was successful when the ratio of myricetin, acrylamide (AM), and ethylene glycol dimethacrylate (EGDMA) was established at 1 : 4 : 20. A series of characterizations were performed to validate the successful synthesis, morphology, structural properties, and magnetic strength of the materials. The super-magnetic Fe₃O₄–NH₂@MIP demonstrated significant adsorption capacity and stability. The adsorption behavior of Fe₃O₄–NH₂@MIP for myricetin was effectively characterized by the Langmuir isotherm model and the Pseudo-second order kinetic model. Additionally, these materials were employed for the extraction and quantification of myricetin in pomegranate pomace under optimal conditions. The experimental results indicate that the adsorption capacity of Fe₃O₄–NH₂@MIP was up to 19.10 μg mg⁻¹ under the best conditions, with an adsorption time of 60 minutes and a myricetin concentration of 100 μg mL⁻¹. Fe₃O₄–NH₂@MIP posses high selectivity for myricetin compared to rutin and resveratrol, the adsorption capacity was up to 18.8 μg mg⁻¹, 4.1 μg mg⁻¹ and 3.7 μg mg⁻¹, respectively. And the content of myricetin in the pomegranate pomace was calculated to be 5.01 μg g⁻¹. The findings indicate that the proposed methodology serves as a viable alternative for the selective quantification of myricetin in samples characterized by complex matrices.