A reaction-based system for the colorimetric detection of glyphosate in real samples

Glyphosate is widely used herbicides and causes several diseases in humans. Therefore, the detection of glyphosate is curial and urgent. Studies on the detection of glyphosate in literature are often based on inhibition of the enzyme acetylcholinesterase. In this study, we developed two simple colorimetric sensors, BP-Cl and CP-Cl, by linking 3-chloro-4-methylpyridine with 4-(dimethylamino)cinnamaldehyde or 4-(dimethylamino)benzaldehyde in a one-step reaction. The colorimetric and optical sensing properties of these compounds were investigated by the naked-eye and UV-Vis spectrophotometer in ACN/HEPES buffer (5 mM pH 8.0, 1:1 v/v). The sensors displayed high sensitivity and selectivity for glyphosate by color changes, which ranged from colorless to yellow for BP-Cl and yellow to orange for CP-Cl. The detection limits of BP-Cl and CP-Cl by the naked-eye detection were found as 15 µM and 10 µM. On the other hand, the detection limits of BP-Cl and CP-Cl via UV-Vis measurements were calculated as 0.847 µM and 1.23 µM, respectively. Moreover, the sensors were able to monitor glyphosate in water samples using the naked-eye, UV-Vis spectroscopy, and filter paper strips.