Modification of boron-doped diamond electrode with gold nanoparticles synthesized by allyl mercaptan as the capping agent for arsenic sensors

Abstract

Gold nanoparticles (AuNPs) were synthesized using allyl mercaptan (C3H6S) as the capping agent. It was expected that high affinity of gold to groups containing S as well as double bonds in allyl mercaptan structure can be used to form covalent bonds between AuNPs onto the BDD surface. The characterization of AuNPs using a UV-Visible Spectrophotometer produced specific wavelengths of gold nanoparticles in the range of 510-580 nm, while characterization using Transmission Electron Microscopy (TEM) and Particle Size Analyzer (PSA) showed an average size of AuNPs at 29 ± 5 The synthesized AuNPs were deposited on the surface of the BDD electrodes by immersion method under UV light (λ = 254 nm) and characterized using X-Ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS). Examination of arsenic sensor was carried out using the Anodic Stripping Voltammetry (ASV) technique. Measurements of As3+ using AuNPs-modified BDD (AuNPs-BDD) electrode showed current responses with good linearity (R2 = 0.99) in the concentration range 0-100 μM with limit detection values of As3+ of 0.064 μM.