Gold nanoparticles based electrochemical sensor for sensitive detection of uranyl in natural water

To precisely determine uranium in aqueous solution, we combined the synthesis of gold nanoparticles (AuNPs) with stripping voltammetry to develop a new electrochemical detection method with high sensitivity toward uranyl ions on account of its enrichment by deposition and determination by stripping. The uranyl was reduced and deposited on the surface of the electrode followed up with a stripping process catalyzed by AuNPs to determine the concentration of uranyl ions. The experimental parameters, such as pH, deposition potential and time were optimized. Under optimal conditions, the stripping voltammetry response of the modified electrode to uranyl shows a linear relationship with the concentration from 2.4 μg L−1 to 48 μg L−1 and 48 μg L−1 to 480 μg L−1, respectively. The AuNPs based electrode could be used to determine the concentration of uranyl ion in a few minutes with a detection limit of 0.3 μg L−1. The reproducibility and reliability of the electrode were also evaluated with good results. Finally, the proposed procedure was successfully applied to the determination of uranyl ions in natural water. This method is potentially applicable for the on-site environmental analysis.