Development of a NIR fluorescent probe HDI based on Zinc-mediated competitive coordination for multidimensional detection of glyphosate in complex systems

Glyphosate, a widely used organophosphorus herbicide, poses significant threats to ecological security and food safety due to its residue accumulation. A near-infrared (NIR) fluorescent probe, HDI, was designed and synthesized for the detection of glyphosate (Glyp) based on a Zn 2 + -mediated competitive coordination mechanism. HDI formed a non-fluorescent complex with Zn 2+ , which was selectively disassembled by Glyp through phosphonate-carboxylate chelation, resulting in a restored "off–on" NIR emission at 620 nm. The coordination mode and displacement mechanism were corroborated by Job's plot, HRMS, 1 H NMR, FT-IR, and DFT calculations. The HDI-Zn 2+ system exhibited a low limit of detection (10.1 nM), a broad tolerant pH range (5−8), and high selectivity against 29 common ions and biomolecules. Satisfactory spike-recovery rates (95.3%-107%, RSD < 4.90%) were obtained in environmental water, soil, and food extracts. Furthermore, Glyp was visualized in living HeLa cells, zebrafish embryos, and mice with low cytotoxicity, and fluorescence signals were predominantly localized in the liver. This work establishes a reliable chemosensing platform for trace glyphosate surveillance in food safety and environmental monitoring.