Fast-responsive and multi-applicable fluorescent turn-off chemodosimeter for monitoring hypochlorite: Application to test strips, water samples, disinfectants and bioimaging

Due to the twin-demic of COVID-19 and flu virus, disinfectants containing ClO^- have been widely used nowadays. Therefore, it is urgent to develop a sensor capable of efficiently detecting toxic hypochlorite. We present the invention and assessment of a fast-responsive and multi-applicable chemodosimeter sensor ETA (2-(2-((1E,2E)-3-(4-(dimethylamino)phenyl)allylidene)hydrazineyl)-N,N,N-trimethyl-2-oxoethan-1-aminium chloride) for monitoring ClO^‑. In pure water, adding ClO^- to ETA caused a turn-off fluorescence within 2 sec. These changes made it possible to quickly detect ClO^- with a high level of selectivity. ETA displayed a low detection limit (0.68 μM) to ClO^-. Using UV–vis titrations, ESI-MS and DFT calculations, we were able to demonstrate the detection mechanism, in which ETA was cleaved by ClO^-. In particular, we established the possibility for reliable ClO^- detection in environmental systems such as actual water samples, disinfectants, living cells, zebrafish and celery, in addition to confirming the practicality of ETA utilizing test strips.