Fabrication of N,N-dimethyldodecylamine functionalized magnetic adsorbent for efficient enrichment of flavonoids

A new N,N-dimethyldodecylamine functionalized magnetic adsorbent (Fe₃O₄@MDHM) was fabricated and used for the efficient enrichment of flavonoids under the format of magnetic solid phase extraction (MSPE). Different techniques were utilized to characterize the spectroscopic, morphology and magnetic properties of the prepared adsorbent. Under the optimized extraction conditions, the Fe₃O₄@MDHM displayed satisfactory enrichment performance to flavonoids by means of hydrophobic, ion-exchange and electrostatic interactions. Furthermore, a sensitive, quick and environmentally friendly analytical method for the determination of flavonoids in grape juice was established by the combination of Fe₃O₄@MDHM/MSPE with high performance liquid chromatography-diode array detection (HPLC-DAD). Results indicated that the linear ranges for target analytes were in the range of 0.5-200.0 μg/L, with good correction coefficients (R²＞0.99). The limits of detection (S/N = 3) and limits of quantification (S/N = 10) for flavonoids were in the ranges of 0.080-0.12 μg/L and 0.27-0.40 μg/L, respectively. The quantification of flavonoids in real grape juices were used to inspect the applicability of proposed Fe₃O₄@MDHM/MSPE-HPLC-DAD method. As a new MSPE adsorbent, the Fe₃O₄@MDHM exhibited some merits such as quick extraction procedure (extraction time, 13 min), high enrichment performance (enrichment factors, 60-69), low consumption of organic solvent (0.49 mL methanol) for the separation and determination of flavonoids.