A fast-responding, highly sensitive detection system consisting of a fluorescent probe and palladium ions for N₂H₄ in environmental water and living cells

Hydrazine (N₂H₄), as a chemical material and high-energy fuel, has been widely used in industry and aerospace. However, the large-scale application of N₂H₄ poses a great risk to the environment and humans due to the strong corrosiveness and toxicity of N₂H₄. Herein, based on the reaction mechanisms of N₂H₄-induced Pd²⁺ reduction, Pd⁰-mediated allyl cleavage and intramolecular cyclization, a new fluorescent system consisting of a probe BINC and Pd²⁺ was designed for detecting N₂H₄. After adding N₂H₄, the BINC-Pd²⁺ system emits bright green fluorescence in less than 10 minutes, which is suitable for rapid naked-eye recognition of N₂H₄. Even when coexisting with various cations, anions, biological substances and amines, the BINC-Pd²⁺ system exhibits a selective and stable fluorescence response to N₂H₄. Moreover, the fluorescence intensity at 519 nm has good linearity with the N₂H₄ concentration in the range of 0-10 μM. The detection limit is 26 nM (0.83 ppb), which is lower than the threshold limit (10 ppb) of N₂H₄ in drinking water. Our results indicate that the BINC-Pd²⁺ system can be used for quantitative analysis of N₂H₄ in environmental water with recovery rates of 95.1-103.9%, as well as fluorescence imaging of N₂H₄ in living cells.