A dual quantum dots-based ratio fluorescent probe for detecting Glyphosate in agricultural products

Glyphosate (Gly) is one of the most widely used herbicides globally. It is essential to conduct quantitative monitoring of Gly in the environment to avoid unnecessary exposure. In this study, we present the development of a novel ratiometric fluorescent probe based on blue carbon dots (bCDs) and red quantum dots (rQDs) for the sensitive and selective detection of Gly in agricultural products. The fluorescence of rQDs is rapidly quenched upon interaction with Gly by intramolecular charge transfer (ICT), serving as the detection signal, while the fluorescence of bCDs remains constant, acting as an internal reference. By measuring the ratio of the fluorescence intensities of bCDs and rQDs ( I 440 / I 640 ), quantitative detection of Gly was achieved. The probe demonstrated a detection limit (LOD) as low as 0.11 μM, with a strong linear response over a concentration range of 0.5 to 200 μM. The developed method was successfully applied to detect Gly residues in real agricultural products (potatoes, gingers and apples), yielding satisfactory recovery rates and demonstrating high resistance to interference from other compounds. This study provides a reliable, efficient, and practical tool for environmental monitoring and food safety assessments.