Methyltrimethoxysilane modified tin dioxide microspheres with hydrophobic networks and abundant adsorbed oxygen for efficient solid-phase microextraction of polychlorinated biphenyls

Methyltrimethoxysilane (MTMS) modified tin dioxide microspheres (MTMS/SnO₂) were prepared by a facile hydrothermal method and heated reflux reaction strategy. The characterization results indicate that the modification of MTMS induced the formation of a hydrophobic network within the composites, while maintaining abundant adsorbed oxygen species. Subsequently, the MTMS/SnO₂ microspheres were used as a solid-phase microextraction (SPME) coating for the efficient extraction and sensitive determination of trace polychlorinated biphenyls (PCBs) in aqueous solutions coupled to gas chromatography-mass spectrometry. MTMS/SnO₂ coating exhibited superior extraction performances for PCBs compared with commercial SPME and pure SnO₂ microspheres coatings, owing to the hydrophobic crosslinking and adsorbed oxygen-enhanced hydrogen bonding. The proposed analytical method presented respectable linearity in the concentration range 0.25–1000 ng L⁻¹, with low limits of detection varying from 0.036 to 0.14 ng L⁻¹ for seven PCBs and excellent precision, with relative standard deviations of 5.7–9.8% for a single fiber and 8.2–13.1% for five fibers. Finally, the proposed method was successfully used for determination of PCBs in real water with recoveries ranging from 75.8 to 115.6%. This study proposed a new type SPME coating of MTMS/SnO₂ microspheres, which extended the potential of SnO₂ in capturing and determining organic pollutants.