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

The outbreak of the COVID-19 has resulted in a great increase in the use of HO 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 HO disinfectant can threaten human health and damage the water environment. Therefore, it's of great importance to detect HO in aquatic environments and biological systems. Herein, we proposed a novel ESIPT ratio fluorescent probe (named probe 1) for detecting HO in water environment and biosystems. Probe 1 emits blue fluorescence as the introduction of the phenylboronic acid disrupts the ESIPT process. After reacting with HO, 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 HO. Importantly, it has been successfully used to detect HO not only in actual water samples, but also endogenous and exogenous HO in living cells. The characteristics of probe 1 have a wide range of applications in environmental and biological systems.