Preparation of naphthyl functionalized magnetic nanoparticles for extraction of polycyclic aromatic hydrocarbons from river waters

A novel core-shell structured magnetic sorbent, naphthyl functionalized magnetic nanoparticles (Fe3O4@SiO2@Nap), was prepared and successfully applied for the magnetic solid-phase extraction (MSPE) of polycyclic aromatic hydrocarbons (PAHs) from river water samples. The analytes were finally determined by high performance liquid chromatography coupled with fluorescence detection (HPLC-FLD). Seven kinds of PAHs were selected as the model analytes, including fluorene (Flu), fluoranthene (Fla), anthracene (Ant), pyrene (Pyr), benz[a] anthracene (BaA), benzo[b] fluoranthene (BbF) and benzo[k] fluoranthene (BkF). Transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), Fourier transform infrared spectrometry (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the sorbent. The main influencing parameters including sorbent amount, desorption solvent, sample volume and extraction time were optimized to achieve the highest recovery rate. Under the optimal conditions, only 40 mg of the Fe3O4@SiO2@Nap sorbent was used to extract the PAHs. The linear ranges of all the seven PAHs were 0.5-100 ng L-1 with the limits of detection (S/N - 3) ranging from 0.04 to 0.12 ng L-1. The repeatability was investigated by evaluating the intra-and inter-day precisions with relative standard deviations (RSDs) lower than 4.3%. Finally, the proposed method was successfully applied for the determination of PAHs in river water samples with recoveries in the range of 89.6-106.8%.