Fabrication of molecularly imprinted polymers based on magnetic covalent organic framework for highly selective and sensitive analysis of genistein in F. Philippinensis

Flemingia philippinensis Merr.et Rolfe (F. philippinensis) is an important food ingredient as well as a traditional Chinese medicine with numerous pharmacological actions. Unfortunately, there was no defined method for monitoring the quality of F. philippinensis in the Chinese Pharmacopoeia. In this study, a magnetic covalent organic framework molecularly imprinted polymers (MCOFs-MIPs) was prepared using MCOFs as a support material, genistein (Gen), which was abundant in F. philippinensis, as a template molecule, and acrylamide as a functional monomer. The preparation process of MCOFs-MIPs was optimized and their structures and adsorption characteristics were characterized. In the selectivity test, the imprinting factor of Gen was 1.93, demonstrating that the imprinting effect of MCOFs-MIPs could selectively enrich Gen in complex samples. Following that, a new and effective quality control method (Gen-MCOFs-MIPs-HPLC) was established to determine Gen content in F. philippinensis roots. The method showed good linearity (R2 = 0.9936) in the range of 0.12–80 µg mL−1. The recoveries of Gen in F. philippinensis high, medium and low samples were 90.5–91.0 %, 92.1–100.1 and 92.8–100.8, respectively. Stability and reproducibility tests revealed that this method was stable (RSD of 1.20 %) and reproducible (RSD of 0.70 %). Moreover, the calculation showed that the amount of Gen in the F. philippinensis powder was 0.4489 mg g−1. As a result, the approach was shown to be simple, repeatable, and stable, and it provided a sensitive and reliable method for the extraction and detection of Gen in natural products.