Zirconium-Based MOF (UiO-66) Anchored on Magnetic Graphene Oxide as a Superior Sorbent for the Determination of Polycyclic Aromatic Hydrocarbons in Water Samples

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are toxic and persistent environmental contaminants that are frequently present at trace levels in complex aqueous matrices, making their accurate determination analytically challenging. In this study, a hierarchical magnetic nanocomposite based on graphene oxide (GO), magnetite nanoparticles, and UiO-66 metal–organic framework (MGO@UiO-66) was synthesized and applied as an efficient sorbent for the magnetic solid-phase extraction (MSPE) of PAHs from environmental water samples. The nanocomposite was prepared through sequential oxidation of graphite, in-situ deposition of Fe₃O₄ nanoparticles, and solvothermal growth of UiO-66 on the magnetic GO surface. The synthesized material was characterized using Fourier-transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), Brunauer–Emmett–Teller (BET) surface area analysis, and vibrating sample magnetometry (VSM). The obtained results confirmed the successful formation of a porous magnetic composite with high surface area and excellent magnetic responsiveness. Key extraction parameters affecting the analytical performance were systematically optimized. Under the optimized conditions, the proposed method coupled with gas chromatography–flame ionization detection (GC-FID) exhibited wide linear ranges (0.005–100 ng mL⁻¹), low limits of detection (0.002–0.003 ng mL⁻¹), and satisfactory precision (RSDs below 4.5%, n = 5). The applicability of the method was successfully validated using different real water samples, including drinking water, seawater, spring water, and wastewater, with relative recoveries ranging from 96.2% to 99.6%. The results demonstrate that the developed MGO@UiO-66-based MSPE method provides a rapid, sensitive, and reliable approach for the determination of trace PAHs in environmental water samples.