Determination of mercury (II) ions based on silver-nanoparticles-assisted growth of gold nanostructures: UV-Vis and surface enhanced Raman scattering approaches

Innovative dual detection methods for mercury((II)) ions (Hg-(II)) have been developed based on the formation of gold nanostructures (AuNSs) following the addition of mercury-containing solution to a mixture containing an optimized amount of Au-(III), H2O2, HCI, and silver nanoparticles (AgNPs). In the absence of Hgol), the addition of Aum, H202, and HCI to the AgNPs solution changes the solution's color from yellow to red, and the absorption peak shifts from 400 to 526 nm, indicating the dissolution of AgNPs and the formation of gold nanoparticles (AuNPs). Because of the spontaneous redox reaction of Hg-(II) toward AgNPs, the change in the amount of remaining AgNP seed facilitates the generation of irregular AuNSs, resulting in changes in absorption intensity and shifting the peak within the range from 526 to 562 nm depending on the concentration of Hg-(II). Under optimal conditions, the limit of detection (LOD) for Hgol) at a signal-to-noise ratio (S/N) of 3 was 0.3 mu M. We further observed that AgNP-assisted catalytic formation of Au nanomaterials deposited on a surface enhanced Raman scattering active substrate significantly reduced the Raman signal of 4-mercaptobenzoic acid, dependent on the He-(II) concentration. A linear relationship was observed in the range 0.1 nM-100 mu M with a LOD of 0.05 nM (S/N 3.0). As a simple, accurate and precise method, this SERS-based assay has demonstrated its success in determining levels of Hg-(II) in real water samples. Published by Elsevier B.V.