A Highly Sensitive Colorimetric Determination of Paraquat by Silver Nanoparticles

In this work, we describe a simple, selective and sensitive colorimetric method for the detection of Paraquat. In this approach, the synthesized silver nanoparticles (AgNPs) solution was stabilized by the citrate anions which repulsed and protected the AgNPs from aggregation. Paraquat was added to AgNPs solution and was incubated to react for 6 min. The resulting mixture color was changed. These processes were studied and characterized by UV-Vis spectroscopy. Several parameters such as size and concentration of nanoparticles, reaction time and pH of medium that governed the analytical performance of the method have been studied in detail and optimized. Paraquat could be selectively detected in concentration range from 0.1to 0.02μM with a limit of detection as 0.01μM. Some common ions such Mg+2, Au+2, Cd+2 and No3- showed no interference in the determination of Paraquat.