Study of Glassy Carbon Electrode Preparation Modified by Gold Nanoparticle and Its Application Towards the Determination of Chromium(VI) with the Influence of Chromium(III), Nickel(II) and Zinc(II) using Voltammetry.

Study of Glassy Carbon Electrode Preparation Modified by Gold Nanoparticle and Its
Application Towards the Determination of Chromium(VI) with the Influence of
Chromium(III), Nickel(II) and Zinc(II) using Voltammetry
Santhy Wyantuti1, Roekmi-ati Tjokronegoro1
1
Jurusan Kimia FMIPA Universitas Padjadjaran
Email : shanty.wyantuti@unpad.ac.id

The current advance in nanotechnology goes through an innovation in the analysis using
voltammetry method. One of the innovations is by taking advantage of electrode that is
modified by gold nanoparticle. Gold nanoparticle is sensoric material that works through non
specific interaction. Beside that, gold nanoparticle can be modified using glassy carbon so that
it can increase its analysis performance in the determination of chromium (IV). Chromium
with highest toxicity level is present as chromium (IV). An effective and fast method to analyse
the toxic chromium (IV) is needed. However, the influence of chromium (III), nickel (II) and
zinc (II) needs to be anticipated in the electrochemical analysis of chromium (IV) as these ions
have similar electrochemical properties with chromium (IV). Voltammetry method with
differential pulse has been applied for the determination of chromium (IV) using glassy carbon
electrode that is modified by gold nanoparticle. This method involves the preparation of gold
nanoparticle and the electrode modification of glassy carbon through self-assembly. The
electrode performance for the determination of chromium (IV) resulted in concentration range

of 0.050 – 0.250 µg/L, sensitivity of 2.25 x 10-3 and accuracy of 94.00%. Study of the metallic
ions influence showed that chromium (III), zinc (II) and nickel (II) did not give any significant
influence in the measurement.

Study of Glassy Carbon Electrode Preparation
Modified by Gold Nanoparticle and Its Application
Towards the Determination of Chromium(VI)
with the Influence of Chromium(III), Nickel(II) and
Zinc(II) using Voltammetry
Santhy Wyantuti1, Roekmi-ati Tjokronegoro1,Yeni Wahyuni Hartati1,
Camellia Panatarani2
1Department of Chemistry, University of Padjadjaran, Jl Raya
Bandung-Sumedang km. 21,West Java 40132, Indonesia
2Department of Physics, University of Padjadjaran, Jl Raya BandungSumedang km. 21,West Java 40132, Indonesia
Email : shanty.wyantuti@unpad.ac.id

INTRODUCTION

Background
Gold nanostructures modified glassy carbon electrode → detect Cr(VI) →

stripping voltammetry adsorption (Li et al., 2010)
Highly sensitive Cr(VI) → cyclic voltammetry and linier voltammetry → with
boron-doped diamond electrodes (Fierro et al. 2012)
Proposed research
• develop and modify carbon electrode using gold nanoparticles
• the influence of Cr(III), Ni(II) and Zn(II) towards the electrochemical analysis
of Cr(VI)

Objective
To determine Cr(VI) concentration using voltammetry method.

RESEARCH METHODOLOGY
Preparation of gold nanoparticles
Process of selecting
reduction agent and
capping agent

Gold nanoparticles

Modifications

process

glassy carbon electrode

Gold nanoparticles modified glassy carbon electrode
Characterization
of electrode
processes

Gold nanoparticles modified glassy carbon electrode
Determination process
of Cr(VI)

the
influence
of Cr(III),
Ni(II) and
Zn(II)

Gold nanoparticles modified glassy carbon electrode that sensitive and selective for Cr(VI)

CHARACTERIZATION AuNP

0.01 M HAuCl4
+ water
+ 0.1 M sodium citrate
+ 0.1 M NaBH4

Size of gold
nanoparticle
about 2.2 nm

Fig 1. TEM image of gold nanoparticles

PREPARATION AND CHARACTERIZATION OF AuNP MODIFIED GCE

Gold
nanoparticles
on electrode
surface is

11.55%.

Fig 2. SEM image of gold nanoparticles modified glassy carbon
electrode surface. Modification was conducted using (a)
adsorption and (b) self assembly process

OPTIMUM CONDITION OF AuNP-GCE

Fig. 3. Voltammogram of variation of
deposition potential at (a) 600, (b) 700,
(c) 800, (d) 900 and (e) 1000 mV for 0.5
µg/L Cr(VI) solution with deposition
time 180 s, scan rate 50 mV/s and
amplitude modulation 500 mV

Fig. 4. Voltammogram of variation of
deposition time at (a) 90 s, (b) 120
s, (c) 150 s, (d) 180 s and (e) 210 s
for 0.5 µg/L Cr(VI) solution with
deposition potential 800 mV, scan

rate 50 mV/s and amplitude
modulation 500 mV

Optimum deposition potential is 800 mV and deposition time is 120 s for determination
of 0.5 µg/L Cr(VI) in 0.01 M HCl as supporting electrolyte solution

LINIER CALIBRATION CURVE OF VARIOUS Cr(VI)

Fig. 5. Voltammogram of various Cr(VI)
concentration (0 – 0.25 µg/L) with
deposition potential 800 mV,
deposition time 120 s, scan rate 50
mV/s and amplitude modulation
500 mV

Fig. 6. Calibration curve of various Cr(VI)
concentration with deposition
potential 800 mV, deposition time
120 s, scan rate 50 mV/s and
amplitude modulation 500 mV

Limit of detection is 2.38 ng/L and accuracy of the method is 94.00%

EFFECT OF INTERFERING IONS
 Differential pulse voltammogram of 50
ppb Cr(VI) without foreign ions in 0.01 M
hydrochloric acid in optimum condition
 The percentage variation of the peak
current induced by the presence of
interfering ions with respect to Cr(VI)
alone are: 0.29% for Zn, 3.70% for Cr(III),
0.07% for Ni(II)
 These deviations from Cr(VI)
measurement at 0.9470 V and 1.360 µA
remain acceptable and therefore, the
accurate detection of Cr(VI) is still
possible under these conditions.

CONCLUSIONS
From the present study it is found that AuNP colloid with ~2.2 nm

size is formed by reducing 6 mg of chloroauric acid (HAuCl4) with
1.102 mg sodium borohydrate (in 290 µL water) as reducing agent
in 0.1 M sodium citrate. The percentage of gold nanoparticles
deposited onto glassy carbon electrode by self assembly process is
11.55% from total surface mass of the glassy carbon (C = 76.38%;
O = 12.07%). The electrode performance for the determination of
Cr(VI) resulted in concentration range of 0.050 – 0.250 µg/L,
sensitivity of 2.25 x 10-3 and accuracy of 94.00%. Study of the
metallic ions influence shows that Cr(III), Zn(II) and Ni(II) does
not give any significant influence in the measurement.