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Electrocatalytic Determination of Colloidal Gold Particles Using a Carbon Paste Electrode Pretreated in Cyanide Media
Author(s) -
HernándezSantos David,
Begoña GonzálezGarcía María,
CostaGarcía Agustín
Publication year - 2000
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/1521-4109(200012)12:18<1461::aid-elan1461>3.0.co;2-8
Subject(s) - electrode , cyanide , colloid , detection limit , colloidal gold , adsorption , gold colloid , carbon fibers , materials science , inorganic chemistry , chemistry , chemical engineering , nanotechnology , chromatography , nanoparticle , organic chemistry , composite material , composite number , engineering
A new methodology, based on silver electrocatalytic deposition and designed to quantify colloidal gold adsorbed onto carbon paste electrodes, has been developed in this work. Silver (contained in 1.0 M NH 3 ) electrodeposition at –0.18 V only occurs when oxidized colloidal gold is attached to the electrode. Adequate oxidation of gold particles is necessary, and it was carried out in 0.1 M H 2 SO 4 at + 1.35 V. In order to use the same electrode for several assays, a cleaning step in KCN, which removes colloidal gold from the electrode surface, was included. To obtain reproducibility in the analytical signal, the electrode surface must be suitably pretreated; cyanide ions were also used for this purpose. Finally, a very low detection limit (250 gold particles μL –1 ) was achieved with this novel methodology.