A high-performance quinoxaline-based ratiometric fluorescent probe for hypochlorous acid monitoring and bioimaging in food and biological systems

Abstract

As a biologically significant reactive oxygen species (ROS), hypochlorous acid (HClO) fulfills dual and critical roles within host defense systems, industrial disinfection, and water treatment. However, its excessive use poses risks to environmental safety, food quality, and human health. There is therefore an urgent need for efficient methods to monitor HClO in complex environments and living systems. In this work, we developed a high-performance ratiometric fluorescent probe, SP ((E)-O-(4-(2-(4-methyl-3-oxo-3,4-dihydroquinoxalin-2-yl)vinyl)phenyl)dimethylcarbamothioate). This probe exhibits a specific ratiometric fluorescence response to HClO, featuring fast response (<1 min), high sensitivity (LOD = 48.89 nM), a broad pH tolerance (3–9), and excellent biocompatibility. In practical applications, SP, real-time visualization of intracellular HClO, whether of endogenous or exogenous origin, is achieved in living onion epidermal cells, wheat roots, and zebrafish. Moreover, portable test strips based on SP allow rapid, instrument-free visual detection of HClO in water samples. Significantly, visual tracking of HClO in frozen seafood has been successfully demonstrated using SP. This methodology thereby furnishes a dependable and user-friendly tool for HClO monitoring within the domains of food safety and biological systems.