Dual-channel fluorescent probe for in-situ differential detection of HClO and H2S in crops and food.

Hypochlorous acid (HClO) and Hydrogen sulfide (H2S) are vital redox regulators in crops, yet their imbalance can trigger oxidative stress. Simultaneous detection of both is challenging with conventional single-target probes. To address this, we engineered a dual-functional probe, ZZ, based on a coumarin-quinolinium structure. It selectively identifies HClO and H2S via distinct fluorescence channels: blue emission for HClO and near-infrared (NIR) for H2S. Additionally, it shows a visible colour change from yellow to colorless or red upon exposure to HClO or H2S, respectively, enabling both fluorescent and colorimetric readouts within a single sensing platform. The probe was effectively used for real-time imaging in live cells, zebrafish, and plants under stress. When integrated with a portable device, it also facilitated rapid, in-situ quantification of HClO in foods and H2S in beverages. This work establishes a versatile, field-deployable tool for investigating HClO-H2S crosstalk in agriculture and enhancing food safety surveillance.