Sensitive Detection of Glyphosate Based on Luminescence Resonance Energy Transfer Between Upconversion Nanoparticles and Naphthalimide Dye

Glyphosate (Gly) is one of the most widely used herbicides worldwide due to its cost‐effectiveness in weed control and its indirect effects on crop yields. However, in 2015, the International Agency for Research on Cancer classified Gly as “probably carcinogenic to humans,” prompting restrictions in several countries, while its large‐scale use persists in developing regions. This scenario highlights the urgent need for sensitive and reliable methods for Gly monitoring. In this work, we report a fluorescence‐based Gly sensor that operates via luminescence resonance energy transfer (LRET). The system uses Gd 2 O 3 :Er upconversion nanoparticles (UCNPs) as donors and a naphthalimide‐derived dye (NATP) as the energy acceptor. The adsorption of NATP onto UCNPs enables efficient LRET, which is selectively disrupted upon Gly binding, resulting in fluorescence recovery of the nanoparticles. This displacement assay was successfully applied to Gly detection over a wide concentration range, yielding a linear response with a detection limit (LOD) of 493.14 nM and a quantification limit (LOQ) of 1494.36 nM. These findings establish a novel LRET‐based sensing platform for Gly, offering high sensitivity, cost‐effectiveness, and potential applicability in portable sensors for on‐site environmental monitoring.