Functionalized magnetic nanomaterials as recyclable adsorbents for efficient flavonoid enrichment in Scutellaria Radix

A magnetic composite (Fe3O4@SiO2@PNIPAM-co-NHMA) with high adsorption capacity and recoverability was developed for the enrichment and determination of flavonoids in Scutellaria Radix (SR). A magnetic solid-phase extraction (MSPE) technique using Fe3O4@SiO2@PNIPAM-co-NHMA absorbent in combination with high-performance liquid chromatography (HPLC) was developed for selectively enrichment and determination of the biologically active flavonoids in the aqueous extract of SR, including baicalein, baicalin, wogonoside and wogonin. Under the optimized experimental conditions, the magnetic adsorbent could adsorb up to 77.0 ± 0.98 % − 98.15 ± 0.15 % of four representative flavonoids from SR, with elution rates varying from 55.10 ± 0.25 % to 91.94 ± 1.85 %. The limits of detection (LOD) and limits of quantitation (LOQ) were 0.01–0.35 μg/mL and 0.03–0.98 μg/mL, respectively. In addition, it remained effective after six replicates, demonstrating its potential as a recoverable adsorbent for enriching flavonoids in traditional Chinese medicine.