A highly selective fluorescent probe based on rhodamine derivatives for HClO detection in water, food, plants, live cells and zebrafish.

Hypochlorous acid (HClO) exerts diverse biological functions and has broad applications in daily life. Herein, a novel turn-on fluorescent probe, DCOH-OCl, was developed for HClO with rhodamine derivatives as the fluorescent group and N,N-dimethylthiocarbamate as the reactive group. The probe exhibited excellent performance, including fast response (30 s), wide pH range (3-10), high selectivity, and strong anti-interference capability. DCOH-OCl allowed quantitative determination of HClO in environmental and food samples and fluorescence imaging of HClO in living cells, zebrafish, and various plants. Especially, DCOH-OCl is the first fluorescent probe capable of visualizing HClO in medicinal plants. Furthermore, this probe enabled real-time and non-destructive monitoring of HClO fluctuations in wheat roots subjected to heavy metal stress. This study provides direct visual evidence of plant responses to heavy metal stress and offers a practical tool for agricultural research and crop safety assessment.