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Electrochemical Co-Reduction Synthesis of AuPt Bimetallic Nanoparticles-Graphene Nanocomposites for Selective Detection of Dopamine in the Presence of Ascorbic Acid and Uric Acid.

Zhao Z, Zhang M, Chen X, Li Y, Wang J - Sensors (Basel) (2015)

Bottom Line: In this paper, AuPt bimetallic nanoparticles-graphene nanocomposites were obtained by electrochemical co-reduction of graphene oxide (GO), HAuCl4 and H2PtCl6.The linear range of the constructed DA sensor was from 1.6 μM to 39.7 μM with a detection limit of 0.1 μM (S/N = 3).The obtained DA sensor with good stability, high reproducibility and excellent selectivity made it possible to detect DA in human urine samples.

View Article: PubMed Central - PubMed

Affiliation: The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China. zhaozongya2010@stu.xjtu.edu.cn.

ABSTRACT
In this paper, AuPt bimetallic nanoparticles-graphene nanocomposites were obtained by electrochemical co-reduction of graphene oxide (GO), HAuCl4 and H2PtCl6. The as-prepared AuPt bimetallic nanoparticles-graphene nanocomposites were characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and other electrochemical methods. The morphology and composition of the nanocomposite could be easily controlled by adjusting the HAuCl4/H2PtCl6 concentration ratio. The electrochemical experiments showed that when the concentration ratio of HAuCl4/H2PtCl6 was 1:1, the obtained AuPt bimetallic nanoparticles-graphene nanocomposite (denoted as Au1Pt1NPs-GR) possessed the highest electrocatalytic activity toward dopamine (DA). As such, Au1Pt1NPs-GR nanocomposites were used to detect DA in the presence of ascorbic acid (AA) and uric acid (UA) using the differential pulse voltammetry (DPV) technique and on the modified electrode, there were three separate DPV oxidation peaks with the peak potential separations of 177 mV, 130 mV and 307 mV for DA and AA, DA and UA, AA and UA, respectively. The linear range of the constructed DA sensor was from 1.6 μM to 39.7 μM with a detection limit of 0.1 μM (S/N = 3). The obtained DA sensor with good stability, high reproducibility and excellent selectivity made it possible to detect DA in human urine samples.

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Nyquist plots of bare GCE (a); PtNPs-GR/GCE (b); AuNPs-GR/GCE (c); Au1Pt2NPs-GR/GCE (d); Au2Pt1NPs-GR/GCE (e) and Au1Pt1NPs-GR (f) in 2 mM [Fe(CN)6]3−/4− + 0.1 M KCl solution with the frequencies swept from 106 to 0.01 Hz and the AC voltage amplitude of 5 mV. Inset figure is the Randles circuit model.
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sensors-15-16614-f003: Nyquist plots of bare GCE (a); PtNPs-GR/GCE (b); AuNPs-GR/GCE (c); Au1Pt2NPs-GR/GCE (d); Au2Pt1NPs-GR/GCE (e) and Au1Pt1NPs-GR (f) in 2 mM [Fe(CN)6]3−/4− + 0.1 M KCl solution with the frequencies swept from 106 to 0.01 Hz and the AC voltage amplitude of 5 mV. Inset figure is the Randles circuit model.

Mentions: The electrochemical behaviors of the different nanocomposites were further studied by electrochemical impedance spectroscopy (EIS). Figure 3 showed the typical Nyquist plots of the different electrodes in 0.1 M KCl solution containing 2 mM [Fe(CN)6]3−/4−. For bare GCE (curve a), the electron-transfer resistance (Rct) was estimated to be 496 Ω. The Rct of PtNPs-GR/GCE (curve b) and AuNPs-GR/GCE (curve c) further decreased, corresponding to 110 Ω and 79.6 Ω, respectively, which indicated that monometallic nanoparticles-GR nanocomposites could greatly enhance electron transfer rates. By comparison, the Rct of Au1Pt2NPs-GR/GCE (curve d), Au2Pt1NPs-GR/GCE (curve e) and Au1Pt1NPs-GR/GCE (curve f) obviously reduced to 60.9 Ω, 24.1 Ω and 13.9 Ω, respectively, which implied that AuPt bimetallic nanoparticles-GR nanocomposites provided more efficient electron transfer channels, faster electron transfer rates, and better electric conductivity compared with the corresponding monometallic nanoparticles-GR nanocomposites. However, of these AuPt bimetallic nanoparticles-GR nanocomposites, Au1Pt1NPs-GR/GCE possessed the smallest Rct, which illustrated that the modified electrode owned the fastest electron transfer rates and best conductivity.


Electrochemical Co-Reduction Synthesis of AuPt Bimetallic Nanoparticles-Graphene Nanocomposites for Selective Detection of Dopamine in the Presence of Ascorbic Acid and Uric Acid.

Zhao Z, Zhang M, Chen X, Li Y, Wang J - Sensors (Basel) (2015)

Nyquist plots of bare GCE (a); PtNPs-GR/GCE (b); AuNPs-GR/GCE (c); Au1Pt2NPs-GR/GCE (d); Au2Pt1NPs-GR/GCE (e) and Au1Pt1NPs-GR (f) in 2 mM [Fe(CN)6]3−/4− + 0.1 M KCl solution with the frequencies swept from 106 to 0.01 Hz and the AC voltage amplitude of 5 mV. Inset figure is the Randles circuit model.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541896&req=5

sensors-15-16614-f003: Nyquist plots of bare GCE (a); PtNPs-GR/GCE (b); AuNPs-GR/GCE (c); Au1Pt2NPs-GR/GCE (d); Au2Pt1NPs-GR/GCE (e) and Au1Pt1NPs-GR (f) in 2 mM [Fe(CN)6]3−/4− + 0.1 M KCl solution with the frequencies swept from 106 to 0.01 Hz and the AC voltage amplitude of 5 mV. Inset figure is the Randles circuit model.
Mentions: The electrochemical behaviors of the different nanocomposites were further studied by electrochemical impedance spectroscopy (EIS). Figure 3 showed the typical Nyquist plots of the different electrodes in 0.1 M KCl solution containing 2 mM [Fe(CN)6]3−/4−. For bare GCE (curve a), the electron-transfer resistance (Rct) was estimated to be 496 Ω. The Rct of PtNPs-GR/GCE (curve b) and AuNPs-GR/GCE (curve c) further decreased, corresponding to 110 Ω and 79.6 Ω, respectively, which indicated that monometallic nanoparticles-GR nanocomposites could greatly enhance electron transfer rates. By comparison, the Rct of Au1Pt2NPs-GR/GCE (curve d), Au2Pt1NPs-GR/GCE (curve e) and Au1Pt1NPs-GR/GCE (curve f) obviously reduced to 60.9 Ω, 24.1 Ω and 13.9 Ω, respectively, which implied that AuPt bimetallic nanoparticles-GR nanocomposites provided more efficient electron transfer channels, faster electron transfer rates, and better electric conductivity compared with the corresponding monometallic nanoparticles-GR nanocomposites. However, of these AuPt bimetallic nanoparticles-GR nanocomposites, Au1Pt1NPs-GR/GCE possessed the smallest Rct, which illustrated that the modified electrode owned the fastest electron transfer rates and best conductivity.

Bottom Line: In this paper, AuPt bimetallic nanoparticles-graphene nanocomposites were obtained by electrochemical co-reduction of graphene oxide (GO), HAuCl4 and H2PtCl6.The linear range of the constructed DA sensor was from 1.6 μM to 39.7 μM with a detection limit of 0.1 μM (S/N = 3).The obtained DA sensor with good stability, high reproducibility and excellent selectivity made it possible to detect DA in human urine samples.

View Article: PubMed Central - PubMed

Affiliation: The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China. zhaozongya2010@stu.xjtu.edu.cn.

ABSTRACT
In this paper, AuPt bimetallic nanoparticles-graphene nanocomposites were obtained by electrochemical co-reduction of graphene oxide (GO), HAuCl4 and H2PtCl6. The as-prepared AuPt bimetallic nanoparticles-graphene nanocomposites were characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and other electrochemical methods. The morphology and composition of the nanocomposite could be easily controlled by adjusting the HAuCl4/H2PtCl6 concentration ratio. The electrochemical experiments showed that when the concentration ratio of HAuCl4/H2PtCl6 was 1:1, the obtained AuPt bimetallic nanoparticles-graphene nanocomposite (denoted as Au1Pt1NPs-GR) possessed the highest electrocatalytic activity toward dopamine (DA). As such, Au1Pt1NPs-GR nanocomposites were used to detect DA in the presence of ascorbic acid (AA) and uric acid (UA) using the differential pulse voltammetry (DPV) technique and on the modified electrode, there were three separate DPV oxidation peaks with the peak potential separations of 177 mV, 130 mV and 307 mV for DA and AA, DA and UA, AA and UA, respectively. The linear range of the constructed DA sensor was from 1.6 μM to 39.7 μM with a detection limit of 0.1 μM (S/N = 3). The obtained DA sensor with good stability, high reproducibility and excellent selectivity made it possible to detect DA in human urine samples.

Show MeSH
Related in: MedlinePlus