Fabrication of nanoscale graphitic carbon nitride/copper oxide hybrid composites coated solid-phase microextraction fibers coupled with gas chromatography for determination of polycyclic aromatic hydrocarbons

In this work, a novel nanoscale graphitic carbon nitride hybridized with copper oxide (nano-g-C₃N₄/CuO) composite was prepared and used as the coating of solid-phase microextraction (SPME) for the first time. The coating was applied to adsorption and preconcentration of polycyclic aromatic hydrocarbons (PAHs) including naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, and pyrene from water and soil prior to gas chromatography (GC) analysis. Compared with pristine nanoscale graphitic carbon nitride (nano-g-C₃N₄) or copper oxide (CuO), the as-prepared nano-g-C₃N₄/CuO composite as the coating of SPME provided the best adsorption affinity for PAHs. Moreover, the extraction efficiencies of the nano-g-C₃N₄/CuO coated fibers were much higher than that of bulk-g-C₃N₄/CuO hybrids. The developed method exhibited excellent linearity for target analytes in the range of 0.1-1000 ng/mL with determination coefficient (R²) not lower than 0.9944. The limits of detection (LODs) of the established method for the analysis of PAHs were achieved between 0.025 and 0.40 ng/mL. The relative standard deviations (RSDs) for three replicate extractions with one fiber were determined from 2.5% to 7.3%. The fiber-to-fiber reproducibility (n = 3) was 5.4-12.8%. The prepared coating also demonstrated excellent thermal and chemical stability. The method was successfully applied to analysis of target analytes in water and soil samples and the corresponding contents were calculated between 0.07 and 1.58 μg/g.