An Ag₂ S@ZnS-coated fiber for efficient, long-life solid-phase microextraction of polycyclic aromatic hydrocarbons in...

Although an efficient and stable fiber coating is essential for the development of solid-phase microextraction technique, it remains a challenging prospect. Herein, an inorganic nanocomposite material Ag₂ S@ZnS was prepared and used as a coating for fibers to detect polycyclic aromatic hydrocarbons in water samples in combination with a GC with flame ionization detector. Compared with a single ZnS material, the Ag₂ S@ZnS composite shows many uneven nano-protrusions on the surface of the microspheres. In conjunction with the relatively scattered microstructure of the coating and the effective anion-π interaction formed between ZnS and the hydrocarbons, it has a large specific surface area, fast diffusion of the target molecule on its surface, and appropriate adsorption of the target molecules; therefore, it exhibits good extraction efficiency for the hydrocarbons. Under optimal conditions, the proposed analytical method exhibits superior performance with good linearity (0.01-500 µg/L) and low limits of detection (0.001-0.200 µg/L). Combined with high thermal, chemical, and mechanical stability, the service life of the coating was improved and could be used 200 times without a significant reduction in the extraction performance, and at least 2000 extraction-desorption cycles can be achieved. Satisfactory results were also obtained for the real samples.