Fe3O4 nanoparticles coated with polyhedral oligomeric silsesquioxanes and β-cyclodextrin for magnetic solid-phase extraction of carbaryl and carbofuran

In this study, porous sandwich structure Fe3O4 nanoparticles coated by polyhedral oligomeric silsesquioxanes and beta-cyclodextrin were prepared by surface polymerization and were used as the magnetic solid phase extraction adsorbent for the extraction and determination of carbaryl and carbofuran. The Fe3O4 nanoparticles coated with polyhedral oligomeric silsesquioxanes and beta-cyclodextrin were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, vibrating sample magnetometry, and scanning electron microscopy. After optimizing the extraction conditions, a method that combined magnetic solid phase extraction with high-performance liquid chromatography was developed for the determination of carbaryl and carbofuran in apple. The method exhibited a good linearity in the range of 2-400 mu g/kg for carbaryl and carbofuran (R-2 = 0.9995), respectively. The limits of detection were 0.5 mu g/kg of carbaryl and 0.7 mu g/kg for carbofuran in apple, respectively. Extraction recoveries ranged from 94.2 to 103.1% with the preconcentration factor of 300 and the relative standard deviations were less than 5.9%. These results indicated that the method combined magnetic solid phase extraction with high-performance liquid chromatography and was promising for the determination of carbaryl and carbofuran at trace amounts.