A terthiophene-based “turn-on” fluorescent probe for hypochlorite: From water/soil analysis to on-site food safety screening and bioimaging

Hypochlorite (ClO − ) is widely used as a disinfectant and bleaching agent, but its overuse threatens environmental and food safety, necessitating rapid, sensitive, and field-deployable detection methods. Herein, we introduce a new terthiophene-based “turn-on” fluorescent probe 3 TB for selective ClO − detection. 3 TB exhibits a pronounced green fluorescence turn-on upon ClO − addition, featuring instantaneous response (<30 s), low detection limit (23.7 nM), good photostability (≥6 h), and broad pH tolerance (4–10). 3 TB enables sensitive and quantitative ClO − detection in water/soil/disinfectant/bleach matrices (recoveries: 97.8–102.8%), and permits on-site visual screening of fresh produce. 3 TB -impregnated test strips further permit rapid naked-eye detection in aqueous media, while smartphone-assisted RGB analysis provides instrument-free quantitative detection on food surfaces and test strips. Moreover, 3 TB exhibits favorable biocompatibility, enabling sensitive fluorescence imaging of ClO − in HeLa cells and onion tissues. Collectively, this work affords a versatile fluorescent platform for ClO − monitoring and bioimaging, which holds significant promise for applications in environmental pollution surveillance, biological system analysis, and food safety assurance.