Graphitic carbon nitride derivative with large mesopores as sorbent for solid-phase microextraction of polycyclic...

Although an efficient and stable fiber coating is essential for the development of the solid-phase microextraction (SPME) technique, it remains a challenging prospect. We report herein the construction of graphitic carbon nitride derivative (g-C₃N₄-d) nanosheets having a large surface area, large mesopores (3.15 and 36.6 nm), and abundant adsorption sites, and the application of coating g-C₃N₄-d on an SPME fiber. The coated SPME fiber combined with gas chromatography-mass spectrometry (GC-MS) was used for the determination of polycyclic aromatic hydrocarbons (PAHs). The coating contained large mesopores that accommodated large target molecules and promoted molecular diffusion inside the coating sorbent. The coating demonstrated significant extraction capability toward PAHs because of multiple interactions, including hydrophobic and strong π-π interactions. Under optimal conditions, the limits of detection for PAHs were achieved within the range of 0.01-0.10 ng L^-1. The method developed to detect eight PAHs in six river water samples from different cities, and the recoveries were ranging from 83.3 to 103.0%. The g-C₃N₄-d nanosheet-coated fiber was sufficiently stable to be recycled more than 200 times without obvious loss of extraction capacity. This study describes the development of a novel SPME adsorbent having excellent analytical properties.