Synthesis and Application of an Iron Oxide-Carbon Nanotube-Zeolitic Imidazolate Framework-8 Nanocomposite for Efficient Magnetic Solid-Phase Extraction of Polycyclic Aromatic Hydrocarbons

In this study, a functionalized magnetic nanocomposite (CNT@Fe3O4@ZIF-8) was synthesized by coating ZIF-8 onto carbon nanotubes containing iron oxide and applied as a sorbent for efficient extraction of polycyclic aromatic hydrocarbons (PAH). The synthesized nanocomposite was successfully applied in a magnetic solid-phase extraction (MSPE) protocol coupled with gas chromatography analysis. Through comprehensive optimization studies, the extraction efficiency was maximized by evaluating multiple parameters: adsorbent quantity (10 mg), solvent selection (dichloromethane), contact time (4 min for both extraction and desorption), eluent volume (1.5 mL), and salt concentration (10% w/v). The calibration curves demonstrated excellent linear response across concentrations spanning 0.01 to 500 ng mL−1, with correlation coefficients (R2) between 0.9924 and 0.9954. Method sensitivity was confirmed with detection limits ranging from 0.006 to 0.01 ng mL−1. Method precision was confirmed through replicate analyses at low, medium, and high concentration levels, showing consistent relative standard deviations (RSD%) of 3.7–4.6%. The method also demonstrated good performance for real water samples, with relative recoveries between 96.3% and 99.8%.