Magnetic nanocomposite as sorbent for magnetic solid phase extraction coupled with high performance liquid chromatography for determination of polycyclic aromatic hydrocarbons

Magnetic composites-based adsorbents have received considerable attention in recent years due to their inherent superparamagnetic properties making them desirable for magnetic field assisted separation and enrichment. In this work, a novel magnetic adsorbent, Fe3O4@SiO2@MMTA-Au, was synthesized via 2-mercapto-4-methyl-5thiazoleacetic acid bonding Au (MMTA-Au) deposited on Fe3O4@SiO2. The as synthesized core shell structured adsorbent, Fe3O4@SiO2@MMTA-Au magnetic nanocomposite was characterized with transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), Fourier transform-infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). This material was used as adsorbent of magnetic solid phase extraction (MSPE) to extract 14 polycyclic aromatic hydrocarbons (PAHs) of interest from water samples followed by the determination of their concentrations with high performance liquid chromatography coupled with fluorescence detection (HPLC-FLD). The effects of four parameters of the MSPE were investigated, including the adsorbent mass, extraction time, extraction solvent and adsorption time. Under the optimized conditions, the enrichment factors (EFs) achieved were in the range of 80-98 and the detection limits were from 0.25 to 37.5 ng/L together with the good recoveries ranging from 87.8 to 120.0% of PAHs from water spiked. The developed method was successfully applied to the analysis of PAHs in water samples collected from river and rainfall.