3. Results and discussion
3.1. Characterization of Au deposition
SEM images of the gold nanoparticles electrodeposited onto
the CSPE under different operating conditions are shown in
Fig. 2b–e, which depict depositions of nanoscale-size gold particles.
Increases in both the deposition time and the concentration
of the HAuCl4 had the effect of enlarging the gold nanoparticles
size.
In addition, EDX analysis of the SCPEs confirmed the presence
of deposited gold.
3.2. Electrochemical response of Sb(III) on gold
nanoparticle-modified CSPE
The anodic stripping voltammetric measurements of Sb(III)
using gold solid electrodes did not give off any analytical
signals for very low concentrations of Sb(III). However, the
electrochemical oxidation of Sb(0) to Sb(III) by DPASV can be
observed when using gold nanoparticle-modified CSPE at even
very lowSb(III) concentrations. In fact, a well-defined oxidation
peak may be observed in Fig. 3 at a potential about −0.18V.
As already described above, the characteristics of gold deposition
on the surface electrode is strongly influenced by several
parameters: the two most important being the HAuClO4 concentration
and the deposition time. It has been observed that
a poor response for Sb(III) is obtained for high concentrations
of HAuClO4 and high deposition times. This behaviour can be
explained by the formation of a partial gold film on the CSPE