A practical pH-compatible fluorescent sensor for hydrazine in soil, water and living cells

The excellent water solubility of hydrazine (N₂H₄) allows it to easily invade the human body through the skin and respiratory tract, thereby damaging human organs and the central nervous system. To realize the monitoring of N₂H₄ effectively, first, coumarin was used to construct an inner alicyclic ring as the reaction site, extending the conjugation and strengthening the rigidity of the probe Co-Hy to improve its luminescence performance and enhance its ability to resist acids and alkalis. Second, we introduced a carboxyl group at the ortho position of the inner alicyclic ring to improve the water solubility of Co-Hy, and its strong electron pulling effect increased the activity of the reaction site. Spectroscopy experiments showed that Co-Hy featured excellent water solubility, high pH resistance (pH 4-11), excellent selectivity, fast analysis speed (within 5 minutes), and a low detection limit toward N₂H₄ (69 nM, 2.2 ppb). In addition, test-strip, spray, and cell-imaging experiments confirmed the outstanding application potential of Co-Hy for convenient N₂H₄ analysis in a variety of environments.