Integrated fluorescent sensing of hypochlorite using a carbazole platform: cellular imaging, environmental monitoring, and smartphone analysis

Hypochlorite (ClO- ), a commonly utilized disinfectant and antibacterial agent, is essential in food preservation, water treatment, and biological systems. Excessive ClO- poses significant environmental and health risks; therefore, effective detection methods should be established. This study introduces a novel fluorescent probe, CBZ-Ind for the selective and sensitive detection of ClO- in aqueous environments and living cells. The probe exhibits significant fluorescence properties, rapid response time, exceptional selectivity against competing analytes, and high sensitivity, achieving a low detection limit (LOD) of 190 nM. The structural and electronic effects of ClO- -induced oxidation were investigated using DFT/TD-DFT. The observed changes in the HOMO-LUMO gap and orbital distributions agree excellently with fluorescence observations and show quantitative agreement with UV-Vis lambda_max in THF. The efficient determination of ClO- in authentic water samples and living cells confirms its practical significance. Finally, as the system utilizes a smartphone to interpret signals without requiring specialized equipment with a LOD of 15.2 mu M, it significantly reduces detection costs and demonstrates the potential for rapid on-site ClO- detection.