Magnetic graphene solid-phase extraction in the determination of polycyclic aromatic hydrocarbons in water

Abstract

In this work, magnetic graphene nanocomposite Fe₃O₄/rGO was fabricated by using a solvothermal method and applied to the magnetic solid-phase extraction (MSPE) of polycyclic aromatic hydrocarbons (PAHs) in environmental water samples, followed by gas chromatography-mass spectrometry (GC-MS). Several parameters affecting the extraction efficiency, such as amount of magnetic graphene, extraction time, desorption conditions, were studied in detail. The results showed that Fe₃O₄/rGO has an extremely high adsorption capacity for PAHs, only 10 mg of the adsorbent was needed for 100 mL of water sample, and the PAHs could be completely desorbed with 100 μL of desorption solvent. Under the optimized conditions, a good linearity was obtained in the concentration range of 0.005–5 μg L⁻¹ for 10 low ring PAHs from naphthalene to chrysene, 0.1–5 μg L⁻¹ for benzo[b]fluoranthene, benzo[k]fluoranthene and benzo(a)pyrene. The limits of detection (LOD, S/N = 3) of the method were in the range between 0.02–14.3 ng L⁻¹. The recoveries for PAHs tested in spiked water samples were in the range 75.6–112.4% with relative standard deviations (RSD) ranging from 0.1–9.5%. Finally, the method was successfully applied for the analysis of real water samples in the search for PAHs.