Velvet-like carbon nitride as a solid-phase microextraction fiber coating for determination of polycyclic aromatic hydrocarbons by gas chromatography

In this study, velvet-like carbon nitride (V-g-C3N4) was prepared from urea aqueous solutions by one-step thermal polycondensation. The V-g-C3N4 material was then characterized using a scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier transform infrared spectrophotometer (FT-IR), and nitrogen adsorption-desorption isotherms. The specific surface area of V-g-C3N4 (60.66 m2/g) was 1.8 times that of the carbon nitride (g-C3N4) prepared by the traditional method. V-g-C3N4 was modified on the surface of stainless-steel wire by a sol-gel technique to obtain a solid-phase microextraction (SPME) coating for the extraction of five polycyclic aromatic hydrocarbons (PAHs) from water samples. The chromatography signal of the PAHs extracted using the V-g-C3N4 coating was 1.5 times that when using a g-C3N4 coating, and 5-10 times that when using commercial PDMS. Under the optimized extraction conditions, the linear range of the method developed for the determination of five PAHs was 0.05-100 µg/L, the limits of detection were 0.005-0.012 µg/L, and the recoveries from actual water samples were 85.94-103.47%. Furthermore, the developed SPME device is remarkably durable and can be reused up to 160 times.