A responsive fluorescent probe with ultra-large stokes shift for high-performance HClO detection in aqueous solution...

Hypochlorous acid (HClO), as one of the reactive oxygen species, is generated in the normal aerobic metabolic processes of organisms. An appropriate amount of HClO can effectively eliminate invading pathogens and combat infections. However, when its concentration becomes excessively high, HClO disrupts intracellular homeostasis, resulting in irreversible damage to the organism. Consequently, it plays a pivotal role in physiological activities. In this study, a novel fluorescent probe ES-BQ for detection of HClO was designed and developed based on the benzothiazole-salicylaldehyde skeleton, with its recognition mechanism involving the oxidative cleavage of the CN bond to form an aldehyde derivative in aqueous solution. ES-BQ exhibits advantages such as a large Stokes shift (310 nm), a low limit of detection (LOD = 44.8 nM), high selectivity, and excellent anti-interference capability. In addition, ES-BQ can achieve highly sensitive and accurate detection of intracellular endogenous HClO. Furthermore, the test strips developed based on ES-BQ enable rapid on-site detection of HClO in aqueous solutions.