Abstract: A novel benzothiazole-based fluorescent probe DHB was designed and synthesized, and its structure was characterized using nuclear magnetic resonance (NMR), fourier transform infrared spectroscopy (FT-IR), mass spectrometry (MS) and high-resolution mass spectrometry (HRMS). The research results indicate that probe DHB forms a 1:1 complex with Zn2+, exhibiting strong fluorescence emission and achieving specific recognition of Zn2+ without interference from other coexisting metal ions and anions. The detection limit was 4.01×10?8 mol/L. When glyphosate was further added to the complex DHB-Zn2+, the system exhibited a significant fluorescence quenching effect with a response time of 18 seconds, and was not affected by other organophosphorus pesticides and common anions. The detection limit was as low as 3.81×10?8 mol/L. Meanwhile, the reaction mechanism of probe DHB continuously recognizing Zn2+ and glyphosate was revealed by FT-IR and HRMS. That is, the C O in the structure of probe DHB underwent enol tautomerism, and the enol hydroxyl formed thereby, along with the O H and the nitrogen heteroatom of C N in the probe structure, jointly participated in the coordination with Zn2+. The synergistic coordination of amino, carboxyl and phosphate groups in the glyphosate molecule enabled it to form a stronger complex with Zn2+, resulting in the displacement of Zn2+ from the complex DHB-Zn2+. Furthermore, probe DHB and the complex DHB-Zn2+ can be applied to the analysis and detection of Zn2+ and glyphosate in the environment, which has a certain practical value.

Key words: Benzothiazole, Fluorescent probe, Glyphosate, Zn²⁺