Rapid, Sensitive and Selective Detection of Ametryn Using Gold Nanoparticles as Colorimetric Probes

The purpose of this paper is to develop a sensitive and low cost optical sensor for screening ametryn using bare gold nanoparticles (Au NPs). Based on the distance-dependent optical properties of Au NPs, the presence of ametryn could rapidly induce the aggregation of gold nanoparticles, thereby resulting in red-to-deep blue color change. The concentration of ametryn was determined with a limit of detection (LOD) lower than 1×10^-6 M by the naked eyes and could be further monitored by a UV-vis spectrometer easily. The highest selectivity was achieved in comparison with other eleven pesticides with similar molecular structure, and the possible underlying mechanism was investigated by the simultaneous addition of tiopronin and ametryn in Au NPs solution.