Label-Free Colorimetric Detection of Prothioconazole Using Gold Nanoparticles Based on One-Step Reaction.

One simple, sensitive detection method for pesticide prothioconazole based on citrate-capped gold nanoparticles (AuNPs) in one step at room temperature was presented in this study. Prothioconazole could be easily linked onto the AuNPs through a Au-S covalent bond, and AuNPs undergo aggregation via hydrogen bonds formed among prothioconazole molecules. As a result, the color of AuNP solution changes from wine red to royal purple, which could be monitored by naked eyes and UV-vis spectra. This label-free visual detection method could determine prothioconazole with concentrations ranging from 1.33 to 19.99 μg/L with a detection limit of 0.38 μg/L (S/N = 3). This method was convenient and free of complex equipment and successfully applied to prothioconazole determination in rice field water where it gave satisfactory recoveries.