ORIGINAL ABSTRACT

The widespread use of glyphosate, a broad-spectrum organophosphorus herbicide, has raised increasing concern due to its environmental persistence and potential health hazards. However, its high polarity and lack of chromophores make accurate detection challenging. Here, we report a naphthalimide-based fluorescent probe (NAPA-Al3+) for the rapid and sensitive detection of glyphosate. The probe is constructed by coordination between a pyridinamine-modified naphthalimide fluorophore and Al3+ ions, resulting in quenched fluorescence. Upon the introduction of glyphosate, Al3+ preferentially coordinates with glyphosate, releasing the fluorophore and restoring fluorescence. The NAPA-Al3+ probe detects glyphosate rapidly within 5 s and achieves a low detection limit of 57.5 nM, outperforming most reported glyphosate probes. Furthermore, portable test strips incorporating NAPA-Al3+ were fabricated, which display a distinct blue-to-green color change with increasing glyphosate concentration. Smartphone-assisted colorimetric analysis was further applied to achieve real-time, visual, and quantitative detection. This work demonstrates a simple, low-cost, and highly effective strategy for glyphosate monitoring, providing a promising platform for food safety regulation and environmental surveillance.