Glyphosate detection based on Eu coordination polymer through competitive coordination

Abstract

Glyphosate is a widely used herbicide in agriculture, leading to residues in food and water environments. These residues have been associated with heart disease and neurotoxicity. Therefore, it is urgent to develop new types of sensors for the detection of glyphosate residues. Here, a new coordination polymer, named as HNU-89, is synthesized by the assembly of Eu3+ and coumarin-3-carboxylic acid (HCCA). Benefiting from the hydrophobic ligands, HNU-89 can maintain its structure at pH 2–11. In view of that phosphoric groups in glyphosate molecules can coordinate with Eu3+ and compete with the HCCA ligand, according to the competitive coordination, the interaction weakens the red fluorescence of HNU-89 simultaneously enhancing the blue fluorescence of HCCA, which achieves the ratio fluorescence response for glyphosate detection. The limit of detection (LOD) is 0.08 ppm, meeting the requirements as a sensor. Furthermore, HNU-89 was utilized to detect glyphosate in soybean, corn, rice and tap water.