Considering the environmental and health issues caused by glyphosate, a controversial nonselective herbicide widely used, the development of reliable quantification methods to monitor the concentration of this compound in natural environments is of critical importance. In this work, a carbon paste electrode modified by functionalized saponite clay mineral was applied for the first time for the direct quantification of glyphosate. The grafting of the organophilic cationic silane (dimethyloctadecyl3‐(trimethoxysilyl)propylammonium chloride) was promoted by the highly charged synthetic saponite layers. The characterizations of the organohybrid saponite by Fourier transformed IR (FTIR) and solid state 29 Si NMR spectroscopies confirmed the grafting of the silane while X‐ray diffraction (XRD) analysis revealed the non‐intercalation of the silane in the interlayer space. This surface functionalization resulted in minor modification of the morphology of the saponite particles as observed on the scanning electron microscope (SEM) images. When the functionalized saponite was used as the electrode modifier, the presence of silane increased the glyphosate signal intensity while decreasing the peak potential, certainly through favorable organophilic and electrostatic interactions between the functionalized clay mineral and the negatively charged pesticide. Under optimal experimental conditions (7 %wt in carbon paste and pH of the solution of 8) and for glyphosate concentrations in the range 5 to 60 µM, a detection limit of 0.12 µM was obtained. Excepted for Cu 2+ , which strongly interferes with the glyphosate signal, the other chemical species investigated (Al 3+ , Ca 2+ , Mg 2+ , and paraquat) poorly affect the pesticide detection. Furthermore, this sensor was successfully applied for the quantification of glyphosate in well water, with a recovery higher than 95%.
Tagne et al. (2026) studied this question.