Dual-responsive bis-Schiff base fluorescent probe for simultaneous detection of Zn2+ and HClO in environmental monitoring and information encryption

The dysregulation of zinc ions (Zn2+) and hypochlorous acid (HClO) poses significant threats to ecological systems and human health. Consequently, the development of robust analytical tools for the detection of these ions is imperative. While numerous fluorescent probes exist for individual analytes, the creation of single-molecule platforms for dual detection remains a formidable challenge. In this study, we reported a novel bis-Schiff base fluorescent probe (P-B) for the simultaneous and distinct detection of Zn2+ and HClO. In the presence of Zn2+, the probe displays a substantial “turn-on” fluorescence response at 520 nm with high selectivity, rapid response time (< 60 s) and exceptionally low detection limit of 17.50 nM. In contrast, P-B functions as a “turn-off” sensor for HClO, enabling selective detection with a limit of 0.24 µM. The practical utility of P-B was successfully validated in real-world applications. The instrument was utilized for the on-site, visual screening of Zn2+ contamination in soil samples and for quantitative detection in environmental water. Furthermore, the unique “invisible-to-visible” fluorescence transformation of the compound upon binding with Zn2+ was ingeniously leveraged to develop an advanced information encryption system. This simple, robust, versatile molecular tool holds significant promise for environmental monitoring and information security applications.