Procedia Chemistry 17 2015 170 – 176
1876-6196 © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license http:creativecommons.orglicensesby-nc-nd4.0
. Peer-review under responsibility of Department of Chemistry, Faculty of Mathematics and Natural Sciences, Padjadjaran University
doi: 10.1016j.proche.2015.12.109
ScienceDirect
3
rd
International Seminar on Chemistry 2014
Cyclic Voltammetric Study of ChromiumVI and ChromiumIII on The Gold Nanoparticles-Modified Glassy Carbon Electrode
Santhy Wyantuti
a,
,Yeni Wahyuni Hartati
a
, Camellia Panatarani
b
, Roekmiati Tjokronegoro
a
a
Department of Chemistry, Faculty of Mathematics and Science, PadjadjaranUniversity, Jl. Raya Bandung-Sumedang km. 21, Jatinangor 45363, West Java, Indonesia
b
Department of Physics, Faculty of Mathematics and Science, PadjadjaranUniversity, Jl. Raya Bandung-Sumedang km. 21, Jatinangor 45363, West Java, Indonesia
Abstract
The chromiumVI and chromiumIII depositionson thegold nanoparticles AuNPs-modified glassy carbon electrode GCE from aqueous solutions were studied by means of cyclic voltammetry technique. The deposition processes were investigated at
+25°C. The anodic and cathodic scannings were recorded within the potential range of -500 to 1500 mV. The scan rate and multiple cycling were carried out to examine the behavior of the electroactive species on the electrode surface. The logarithmic
of the plot between Ip and V reflected a diffusion controlled by the irreversible redox reaction of CrIII and an adsorption-driven process. These results strongly suggested that the irreversible redox reaction of CrVI was controlled by the diffusion step.
Keywords: CrIII; CrVI; cyclic voltammetry.
1. Introduction
Analysis of chromium using electrochemical methods has been developed concurrently with increasing types of measurement needs. This development resulted in various modifications on the working electrodes, one of them
beingcarbon-based electrode, which can then be applied for the purposes of analysis
1
. From the various modifications that need to be carried out a study was done to determine the electrochemical processes that occur
around the surface of the electrode. Several processes occur on the electrode surface, electrontransfer, diffusion, and oxidation-reduction reactions. The method used in the study of processes that occur around the surface of the
electrode is cyclic voltammetry
2
. This method was chosen because it is simple, the analysis time is fast, and it has a good precision and accuracy so that it can provide useful information related to the processes that occur at the
electrode surface
3
. The active area of electrochemical sensor research is the development ofworking electrode.The working electrode modifications include: the use of adsorption substances that are irreversible to the desired
function, covalent bonding of the components of the surface, and coating the electrode with a layer of polymer or nano-sized material
4
. Carbon-based electrodes used in the sensor application have the disadvantage that is not
Corresponding author. Tel.: +62227794391; fax: +62227794391. E-mail address:shanty.wyantutiunpad.ac.id
Available online at www.sciencedirect.com
sensitive to CrVI. It is necessary either as a pre-treatment on the surface, or by modifying its surface with gold nanostructures to be sensitive to CrVI
5
. Nano-sized materials used currently is very large, one of which is the use of metal nanoparticles in the field of sensors. The use of metal nanoparticles are very knowledgeable in the field of
sensors due to the metal nanoparticles characteristicas having the nature of catalysis and good surface area. The development ofnano-sized materials on analysis of electrochemical techniques, one of which is the nanotube-based
electrode, has shown an increase in high sensitivity. That is the basis of the electrode made of other types of gold nanoparticle-based, considering that the two electrodes are competing for use in electrochemical analysis. Another
advantage of the gold nanoparticles compared to carbon nanotubes is that it can be produced simpler
6
. Surface modification of carbon-based electrodes with AuNPs generate profits in the field of sensor because it can facilitate
electron transfer between the electrode surface and a carbon-based analyte. In this research cyclic voltammetry used on GCE modified withAuNPs to measure CrVI and CrIII. Between CrIII andCrVI there are significant
differences in toxicity, reactivity and bioavailability
7-8
. Therefore, it is important to distinguish between CrIII to CrVI. In addition, sensitive analysis methods are needed to distinguish them.
2. Experimental
