Efficient detection for Nitrofurazone based on novel Ag₂S QDs/g-C₃N₄ fluorescent probe

In the paper, a novel fluorescent probe based on Ag₂S QDs/g-C₃N₄ composite was synthesized by loading Ag₂S quantum dots (Ag₂S QDs) on the surface of g-C₃N₄ through in-situ synthesis method and developed to detect Nitrofurazone (NFZ) sensitively. The results showed that the linear detection range of Ag₂S QDs/g-C₃N₄ to NFZ was 0-30 μM, with a low detection limit of 0.054 μM. The results of time-fluorescence-resolved spectroscopy and UV-vis absorption spectroscopy exhibited that the possible detection mechanism of Ag₂S QDs/g-C₃N₄ to NFZ was proposed to be Internal Filtration Effect (IFE). Moreover, Multiwfn wavefunction analysis was employed to uncover the possible interaction between the Ag₂S QDs/g-C₃N₄ and NFZ, thereby further revealing the fluorescence detection mechanism from the scale of atoms. Combining experiments and theoretical calculations, we proposed the sensing mechanism of the formation of non-fluorescent ground state complex linked by hydrogen bonds. This work indicated that the Ag₂S QDs/g-C₃N₄ composite processed the ability to detect NFZ efficiently and sensitively.