Colorimetric hydrazine detection and fluorescent hydrogen peroxide imaging by using a multifunctional chemical probe

Among organic small molecules, hydrogen peroxide (H₂O₂) and hydrazine (NH₂NH₂) often cause concern because they are widely used in biological and chemical industries. Here, we present a novel probe RH-1 for colorimetric detection of NH₂NH₂ and fluorescent imaging of H₂O₂. In this probe, rhodamine was used as the main skeleton due to its favorable spectroscopic performance and stable absorption. Importantly, a benzoic acid group is present in the rhodamine skeleton, which can react with NH₂NH₂ by amidation. The rhodamine skeleton can also be modified with chromogens to detect H₂O₂. Results showed that RH-1 can be used for colorimetric detection of NH₂NH₂ and fluorescent monitoring of H₂O₂ with high selectivity and sensitivity. The detection limits for NH₂NH₂ and H₂O₂ were 0.27 and 0.16 μM, respectively. Moreover, RH-1 can fluorescently image H₂O₂ in living cells with low cytotoxicity.