Facile preparation of hexadecyl-functionalized magnetic core-shell microsphere for the extraction of polychlorinated...

Alkyl moieties which can retain target analytes due to their lipophilicity are important in sample preparation. In this work, hexadecyl-functionalized magnetic core-shell microspheres (Fe₃O₄@SiO₂-C₁₆) was successfully prepared by one-pot sol-gel method and used for magnetic solid-phase extraction of polychlorinated biphenyls (PCBs) in environmental water samples. Optimized preparation method was achieved by altering the adding moment of hexadecyl-silane. The resultant materials were systematically characterized by scanning electron microscope, transmission electron microscope, Fourier transform infrared spectroscopy, energy dispersive X-ray spectrometry, tensionmeter, and vibrating sample magnetometer. The results demonstrated that the optimized adsorbent exhibited core-shell structure, superparamagnetic (66 emu/g), and extremely hydrophobic (water contact angle of 122°) properties. To evaluate the extraction performance, the prepared material coupled with gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) was applied to determinate PCBs. The extraction conditions were optimized. Under the optimal conditions, the proposed method showed a good linearity range of 1-100 ng L^-1 with correlation coefficients (R) of 0.9989-0.9993. Based on a signal-to-noise ratio of 3 and 10, the limits of detection (LODs) and limits of quantification (LOQs) were in the range 0.14-0.27 and 0.39-0.91 ng L^-1, respectively. The intra- and inter-day relative standard deviations (RSDs) were less than 9.06%. The absolute recoveries of PCBs in spiked real water samples were in the range of 75.17 to 101.20%. Additionally, reusability and batch-to-batch reproducibility of the resultant material were acceptable with RSDs less than 5.64 and 3.25%, respectively. Graphical Abstract The synthesis procedure of Fe₃O₄@SiO₂-C₁₆ and determination of PCBs in water sample 129 × 50 mm (300 × 300 DPI).