Fabrication of a high selectivity magnetic solid phase extraction adsorbent based on β-cyclodextrin and application for recognition of plant growth regulators.

An adsorbent, consisting of silica-coated FeO grafted graphene oxide and β-cyclodextrin (FeO@SiO/GO/β-CD), which possessed the merits of antioxidation, superparamagnetism, high surface area, high supramolecular recognition and environment friendly, was successfully fabricated. Considering the synergy between β-CD and graphene oxide in adsorption mechanism, the synthesized adsorbent could grasp compounds especially with aromatic structures through π-π interaction, hydrophobic interaction and host-guest inclusion complex forming. Based on the advantages, a magnetic solid phase extraction (MSPE) method for 9 PGRs using FeO@SiO/GO/β-CD as adsorbents was developed in this study. The characterizations of FeO@SiO/GO/β-CD were performed on Fourier transform infrared spectrometry (FT-IR), X-ray photoelectron spectroscopy (XPS), CHNS/O elemental analyzer, scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). Under the optimal MSPE condition, the FeO@SiO/GO/β-CD exhibited selectivity capability toward 9 PGRs when compared with FeO@SiO/GO. Meanwhile, the selectivity capability of FeO@SiO/GO/β-CD was higher than that of FeO@SiO/GO/α-CD except for 4-FPA. When the developed MSPE procedure was coupled with ultra-high performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry (UHPLC-QTrap-MS/MS) to quantitative analysis of 9 PGRs, linearities ranging from 2 to 50 μg/kg were achieved for 9 PGRs with the correlation coefficients (r) in the range of 0.9975-0.9999. The limits of detection (LODs) for 9 analytes varied from 0.04 to 0.29 μg/kg. Finally, the proposed technique was applied to analyze PGRs residues in mutiple vegetable samples.