SYNERGISTIC EFFECT OF GRAPHENE AND
MULTI-WALLED CARBON NANOTUBES ON
GLASSY CARBON ELECTRODE FOR
SIMULTANEOUS DETERMINATION OF URIC
ACID AND DOPAMINE IN THE PRESENCE OF
ASCORBIC ACID
Sijing He, Yanyan Yu, Zuanguang Chen,* Qiujia Shi, and Lin Zhang
School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou
510006, China
*Corresponding author. Tel.: +86 20 3994 3044, Fax: +86 20 3994 3071
E-mail address: chenzg@mail.sysu.edu.cn (Z. Chen)
SUPPLEMENTAL INFORMATION
Preparation of poly(diallyldimethylammonium chloride)-graphene-multiwalled
carbon nanotubes suspension
1.5 mg graphene oxide, 1 mL poly(diallyldimethylammonium chloride) (0.2
wt %), 1 mL hydrazine hydrate (4 wt %), and 4 mL H2O were mixed and sonicated
for 5 minutes to form a homogeneous dispersion. After stirring for 30 minutes at room
temperature, the mixture was heated to 100 °C with a reflux condenser for 30 minutes.
The black poly(diallyldimethylammonium chloride)-graphene dispersion was
1
obtained at a concentration of 0.25 mg mL-1. Centrifugation (15,000 rpm, 10 min) was
used to collect poly(diallyldimethylammonium chloride)-graphene and remove the
excess reagents. For the preparation of the poly(diallyldimethylammonium
chloride)-graphene-multiwalled carbon nanotube modified electrode, 0.5 mg of
multiwalled carbon nanotubes were dispersed in 3 mL
poly(diallyldimethylammonium chloride)-graphene solution (0.5 mg mL-1) and
sonicated for 1 h to form a homogenous mixture.
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Table S1. Analytical figures of merit for modified electrodes reported in the literature.
Linear dynamic range
Limit of detection
Electrode
Reference
-1
-1
(µmol L )
(µmol L )
uric acid
dopamine
uric acid
dopamine
31.0-172.0
29.0-167.0
1.19
0.51
Tsierkezos et al. (2014)
2.0-200.0,
0.4-10.0
1.00
0.20
Yang et al. (2011)
Nitrogen-doped multiwalled carbon
nanotubes/gold nanoparticles
Methylene blue/multiwalled
nanotubes/glassy carbon electrode (GCE)
Multi walled carbon nanotube
Habibia and
0.55-90.0
0.5-100.0
0.42
0.31
/carbon-ceramic electrode (CCE)
Nitrogen doped graphene/GCE
Pournaghi-Azar (2010)
0.1-20.0
0.5-170.0
0.045
0.25
Sheng et al. (2012)
0.5-60.0
0.5-60.0
0.50
0.50
Yang et al. (2014)
2.0-45.0
1.0-24.0
2.00
1.00
Han et al. (2010)
10.0-130.0
10.0-170.0
0.45
0.25
Xu et al. (2014)
2.5-65.0
-
0.10
-
Zhang et al. (2013)
5.0-350.0
10.0-400.0
0.13
0.55
This work
Electrochemically reduced graphene
oxide/GCE
Chitosan/graphene/GCE
Pt/reduced graphene oxide/GCE
Graphene/singlewalled carbon
nanotube/GCE
Poly(diallyldimethylammonium
chloride)/graphene/multiwalled carbon
nanotube/GCE
3
REFERENCES
Habibia, B., and M. H. Pournaghi-Azar. 2010. Simultaneous determination of
ascorbic acid, dopamine and uric acid by use of a MWCNT modified
carbon-ceramic electrode and differential pulse voltammetry. Electrochim. Acta. 55:
5492–5498.
Han, D. X., T. T. Han, C. S. Shan, A. Ivaska, and L. Niu. 2010. Simultaneous
Determination of Ascorbic Acid, Dopamine and Uric Acid with Chitosan-Graphene
Modified Electrode. Electroanalysis. 22: 2001-2008.
Sheng, Z. H., X. Q. Zheng, J. Y. Xu, W. J.B ao, F. B. Wang, and X. H. Xia. 2012.
Electrochemical sensor based on nitrogen doped graphene: Simultaneous
determination of ascorbic acid, dopamine and uric acid. Biosens. Bioelectron. 34:
125-131.
Tsierkezos, N. G., P. Szroeder, and U. Ritter. 2014. Voltammetric study on pristine
and nitrogen-doped multi-walled carbon nanotubes decorated with gold
nanoparticles. Microchim. Acta. 181: 329–331.
Xu, T. Q., Q. L. Zhang, J. N. Zheng, Z. Y. Lv, J. Wei, A. J. Wang, and J. J. Feng.
2014.
Simultaneous determination of dopamine and uric acid in the presence of
ascorbic acid using Pt nanoparticles supported on reduced graphene oxide.
Electrochim. Acta 115: 109–115.
Yang, L., D. Liu, J. S. Huang, T, and Y. You. 2014. Simultaneous determination of
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dopamine, ascorbic acid and uric acid at electrochemically reduced graphene oxide
modified electrode. Sens. Actuators B 193: 166-172.
Yang, S. L., G. Li, R. Yang, M. M. Xia, and L.B. Qu. 2011. Simultaneous
voltammetric detection of dopamine and uric acid in the presence of high
concentration of ascorbic acid using multi-walled carbon nanotubes with methylene
blue composite film-modified electrode. J.Solid State Electrochem. 15: 1909–1918.
Zhang, F. F., J. Tang, Z. H. Wang, and L. C. Qin. 2013. Graphene–carbon nanotube
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121–125.
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Fig. S1.
Influence of the mass ratio of poly(diallyldimethylammonium
chloride)-graphene and multiwalled carbon nanotubes on the oxidation peak
currents of 100 µmol L-1 uric acid and 100 µmol L-1 dopamine in 0.1 mol L-1
phosphate buffer (pH 7.0) at a scan rate of 50 mV s-1.
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Fig. S2.
Cyclic voltammograms of 1 mmol L-1 ascorbic acid, 1 mmol L-1 dopamine,
and 1 mmol L-1 uric acid at a (A) bare glassy carbon electrode, (B)
poly(diallyldimethylammonium chloride)-graphene-glassy carbon electrode, (C)
multi-walled carbon nanotube-glassy carbon electrode, and (D)
poly(diallyldimethylammonium chloride)-graphene-multiwalled carbon
nanotube-glassy carbon electrode in 0.1 mol L-1 phosphate buffer (pH 7.0) at a scan
rate of 50 mV s-1.
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Fig. S3.
(A) Cyclic voltammograms of 1 mmol L-1 uric acid at the
poly(diallyldimethylammonium chloride)-graphene-multiwalled carbon nanotube
glassy carbon electrode at various scan rates (a-r: 20, 60, 120, 180, 220, 260, 300, 340,
380, 460, 500, 560, 640, 680, 720, 760, 800, and 850 mV s-1) in 0.1 mol L-1 phosphate
buffer (pH 7.0); (B) Cyclic voltammograms of 1 mmol L-1 dopamine at
poly(diallyldimethylammonium chloride)-graphene-multiwalled carbon nanotube
glassy carbon electrode at various scan rates (a-i: 10, 30, 40, 70, 100, 120, 140, 200,
and 250 mV s-1) in 0.1 mol L-1 phosphate buffer solution (pH 7.0); (C) anodic and
cathodic peak currents versus scan rate of uric acid; (D) anodic and cathodic peak
currents versus scan rate of dopamine.
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Fig. S4. Differential pulse voltammograms at the poly(diallyldimethylammonium
chloride)-graphene-multiwalled carbon nanotube glassy carbon electrode in 0.1 mol
L-1 phosphate buffer (pH 7.0): (A) 500 µmol L-1 ascorbic acid, 100 µmol L-1
dopamine, and various concentrations of uric acid (a-q = 5, 10, 20, 40, 60, 80, 100,
130, 150, 180, 200, 230, 250, 280, 300, 320, and 350 µmol L-1) and (B) 500 µmol L-1
ascorbic acid, 100 µmol L-1 uric acid, and various concentrations of dopamine
(a-g=10, 30, 50, 100, 200, 300, and 400 µmol L-1). Plots of peak current versus
concentration for (C) uric acid and (D) dopamine.
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