Magnetic molecularly imprinted polymers doped with graphene oxide for the selective recognition and extraction of four flavonoids from Rhododendron species.

Herein, a novel magnetic molecularly imprinted polymer doped with reticular graphene oxide (Fe₃O₄@SiO₂-GO@MIPs) was synthesized for the selective recognition and extraction of 4 flavonoids (farrerol, taxifolin, kaempferol, and hyperin) from Rhododendrons species. The Fe₃O₄@SiO₂-GO@MIPs with lamellar membranes showed outstanding adsorption capacity. The 3D cavities complementary to the "shape" of farrerol were "imprinted" on the polymer framework after removal of farrerol template. Competitive binding assays showed that the polymer has a higher selectivity for farrerol compared with other analogues and references. The Fe₃O₄@SiO₂-GO@MIPs as solid-phase extraction adsorbents combined with liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS) was used for selective determination of four flavonoids from Rhododendrons samples. The limits of detection (LOD) were 0.07, 0.08, 0.06, and 0.08 μg L^-1 for farrerol, taxifolin, kaempferol, and hyperin, respectively. These results suggest that the prepared Fe₃O₄@SiO₂-GO@MIPs have the potential applicability to extract, purify, and enrich flavonoids from herbs, supplements, and other natural products.