Green Synthesized Silver and Gold Nanoparticles for Colorimetric Detection of Hg²⁺, Pb²⁺, and Mn²⁺ in Aqueous Medium

Abstract

In this study, we report a simple and green method for the synthesis of l-tyrosine-stabilized silver (AgNPs) and gold nanoparticles (AuNPs) in aqueous medium under ambient sunlight irradiation. The nanoparticles (NPs) are characterized by UV–visible spectroscopy, high-resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), cyclic voltammetry (CV), and dynamic light scattering (DLS) techniques. The size and shape of the metal NPs could be controlled by changing the concentration of the substrate, metal precursors, and pH of the medium. The synthesized AgNPs are found to be highly sensitive to Hg2+ and Mn2+ ions with the detection limit for both ions as low as 16 nM under optimized conditions. However AuNPs are found to be sensitive to Hg2+ and Pb2+ ions with a detection limit as low as 53 and 16 nM, respectively. The proposed method was found to be useful for colorimetric detection of heavy metal ions in aqueous medium.

Synthesis of Silver Nanoparticles by Reduction of Silver Ion with m-Hydroxybenzoic Acid

“…Polymers such as polyvinyl alcohol stabilize the AgNPs during and after formation of nanoparticles [7]. Development of synthesis method to produce AgNPs with different reducing and capping agent has been reported [8][9][10][11].…”

Biogenic Silver Nanoparticles as Sensors of Cu²⁺ and Pb²⁺ in Aqueous Solutions

“…After the addition of the metal ions, the fluorescent emission is slightly restored (Figure 9). The restoration of fluorescent emission ensures certain degree of detachment of the dye fluorophore from the nanoparticles surface provoked by the metal ions, and proves, thus, the sensing ability of these biogenic Ag-NPs produced by Camellia sinensis extract toward Pb 2+ and Cu 2+ ions [24,25].…”

“…These are epicatechin groups and other flavonols [18][19][20]. In the past few years, silver nanoparticles have attracted interest, due to their potential applications such as: biomedicine [21], as a disinfectant [22] and sensors (biosensors and naked-eyed) [23,24].…”

Nanotechnology Solutions for Global Water Challenges

“…Annadhasan et al reported the use of tyrosine stabilized silver NPs for the colorimetric detection of mercury ions and manganese ions in drinking water (131). The limit of detection for Hg 2+ ions was found to be 19 nM and the limit of detection for Mn 2+ ions was found to be 23 nM.…”