Open AccessChemical Detection by Analyte-Induced Change in Electrophoretic Deposition of Gold Nanoparticles
Author(s) -
Badri P. Mainali,
Francis P. Zamborini
Publication year - 2022
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/ac418c
Subject(s) - electrophoretic deposition , detection limit , melamine , chemistry , nanoparticle , electrophoresis , cyclic voltammetry , indium tin oxide , electrochemistry , colloidal gold , inorganic chemistry , analytical chemistry (journal) , nuclear chemistry , electrode , materials science , nanotechnology , chromatography , coating , organic chemistry
The electrophoretic deposition (EPD) of citrate-stabilized Au nanoparticles (cit-Au NPs) occurs on indium tin oxide (ITO)-coated glass electrodes upon electrochemical oxidation of hydroquinone (HQ) due to the release of hydronium ions. Anodic stripping voltammetry (ASV) for Au oxidation allows the determination of the amount of Au NP deposition under a specific EPD potential and time. The binding of Cr 3+ to the cit-Au NPs inhibits the EPD by inducing aggregation and/or reducing the negative charge, which could lower the effective NP concentration of the cit-Au NPs and/or lower the electrophoretic mobility. This lowers the Au oxidation charge in the ASV, which acts as an indirect signal for Cr 3+ . The binding of melamine to cit-Au NPs similarly leads to aggregation and/or lowers the negative charge, also resulting in reduction of the ASV Au oxidation peak. The decrease in Au oxidation charge measured by ASV increases linearly with increasing Cr 3+ and melamine concentration. The limit of detection (LOD) for Cr 3+ is 21.1 ppb and 16.0 ppb for 15.1 and 4.1 nm diameter cit-Au NPs, respectively. Improving the sensing conditions allows for as low as 1 ppb detection of Cr 3+ . The LOD for melamine is 45.7 ppb for 4.1 nm Au NPs.