Preparation of a zirconium terephthalate metal‐organic framework coated magnetic nanoparticle for the extraction of berberine prior to high‐performance liquid chromatography analysis

In this study, a zirconium terephthalate metal‐organic framework‐coated magnetic nanoparticle (UiO‐66@PA@PEI@Fe3O4) was synthesized for the extraction of berberine prior to high‐performance liquid chromatography analysis. The phytic acid, which could be grafted onto the magnetic nanoparticle through electrostatic interaction with the abundant amino groups of polyethylenimine, possesses outstanding metal ion coordination ability for the immobilization of metal‐organic frameworks UiO‐66. The physicochemical properties of the obtained nanoparticle were thoroughly investigated by a series of characterization techniques. Then, the factors that will affect the extraction efficiency and recovery of berberine were investigated. Results indicated that the material had good stability and reusability, and high adsorption capacity (50.01 mg/g) to berberine through single‐layer adsorption. In addition, a molecular docking study indicated that the interactions between the material and berberine were mainly π‐π stacking and hydrophobic interaction. Finally, the material was successfully applied to the extraction of berberine in Rhizoma Coptidis and Cortex Phellodendri extracts with the recoveries of 76.1% and 71.6%, respectively.