Magnetic/Zeolitic Imidazolate Framework-67 Nanocomposite for Magnetic Solid-Phase Extraction of Five Flavonoid Components from Chinese Herb Dicranopteris pedata

A magnetically functionalized Fe3O4@ZIF−67 metal–organic framework (MOF) was prepared by electrostatic self-assembly using magnetic Fe3O4nanoparticles as the core and ZIF−67 as the shell. The composite was characterized by electron microscopy, X-ray diffraction, Fourier- transform infrared spectroscopy, and Brunauer–Emmett–Teller measurements. Magnetic solid-phase extraction (MSPE) was performed on five flavonoids fromDicranopteris pedatausing Fe3O4@ZIF−67 as an adsorbent. The developed MSPE method was combined with high-performance liquid chromatography–ultraviolet detection to preconcentrate and separate five flavonoids (rutin, quercitrin, kaempferol-3-O-α-L-rhamnoside, quercetin, and kaempferol) fromDicranopteris pedata. The factors affecting the extraction, such as the amount of Fe3O4@ZIF−67 adsorbent, salt ion concentration in the sample solution, vortex time, type and amount of desorbing solvent, concentration of formic acid to acidify the desorbing solvent, and acetonitrile ratio, were optimized. The developed method showed good linearity over the concentration range of 1.09–70.0 μg∙mL−1for the five flavonoids, with R2values between 0.9901 and 0.9945. The limits of detection and average recoveries for the five flavonoids were in the ranges of 39.5–56.2 ng∙mL−1and 92.2–100.7%, respectively. The method presented herein is simple, efficient, and sensitive; it can be used for enrichment analysis of the five flavonoids inDicranopteris pedata.Keywords:magnetic solid-phase extraction;Fe3O4@ZIF−67;Dicranopteris pedata;flavonoids;metal–organic framework materials