An ESIPT-based ratiometric fluorescent probe for detecting H2O2 in water environment and biosystems

The outbreak of the COVID-19 has resulted in a great increase in the use of H2O2 disinfectant, which is listed as one of the commonly used disinfectants for COVID-19 by the U.S. Environmental Protection Agency. However, excessive use of H2O2 disinfectant can threaten human health and damage the water environment. Therefore, it's of great importance to detect H2O2 in aquatic environments and biological systems. Herein, we proposed a novel ESIPT ratio fluorescent probe (named probe 1) for detecting H2O2 in water environment and biosystems. Probe 1 emits blue fluorescence as the introduction of the phenylboronic acid disrupts the ESIPT process. After reacting with H2O2, the phenylboronic acid is oxidatively removed, and the ESIPT process is restored, which makes the fluorescence emission wavelength red-shifted. Probe 1 exhibited a short response time, high sensitivity, and a large Stokes shift to H2O2. Importantly, it has been successfully used to detect H2O2 not only in actual water samples, but also endogenous and exogenous H2O2 in living cells. The characteristics of probe 1 have a wide range of applications in environmental and biological systems.