Self assembly of gold nanoparticles modified electrode for pb and hg detection
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Date
2019-05
Authors
Siti Nasirah Binti Nasrul
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Abstract
In this study, 40 nm gold nanoparticles (AuNPs) were synthesized by using seeded-growth method. The synthesized AuNPs were characterized using Zetasizer analysis, UV- Visible Near-Infrared Spectrophotometer, X-ray Diffractometer (XRD), Transmission Electron Microscopy (TEM). Indium tin oxide on glass (ITO) substrates were used for fabrication of modified electrodes. The AuNPs solutions were used to self-assembled with the aid of Aminopropyltriethoxysilane (APTES) on ITO electrode for the electrochemical detections of Pb(II) and Hg(II). APTES acted as a linker between ITO electrode and AuNPs. Several parameters were investigated which were: effects of APTES concentration(0.3%, 0.5%, 0.75%, 1%) and effect of soaking period(1 hour, 1.5 hour, 2 hour, 2.5 hour) in AuNPs. The AuNPs/APTES/ITO modified electrode were subjected to cyclic voltammetry (CV) and Differential Pulse Anodic Stripping Voltammetry (DPASV) analyses. CV analysis was used to study the electrochemical behaviour while DPASV was performed on each parameters to find the lowest value of limit of detection (LOD) of Pb(II) and Hg(II). Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive Microscope (EDX) analysis were used to observe the morphology of AuNPs/APTES/ITO electrodes. Optimum APTES concentration was 0.5% of APTES concentration with optimum soaking time of 2 hour soaking period in AuNPs for formation of the AuNPs/APTES/ITO modified electrode.The modified electrode showed LOD value 1.18 µg/L for Pb(II) and 0.38µg/L for Hg(II).