专属性螯合剂（03级应用化学专业陈贤光）

铜金二元纳米溶胶修饰电极
对多巴胺的电催化氧化作用
答辩人：陈贤光（03应化）
指导老师：邹小勇教授
2007.6
广州
1. Introduction
1.1 Dopamine （多巴胺）
HO
O
NH2
NH2
- 2e
+ 2e
O
HO
Reductive Structure
Oxidative Structure
O
NH2
HO
C. C. Felix, R. C. Sealy. J. Am. Chem. Soc. , 1981, 103: 2831.
1. Introduction
1.2 Bimetallic nanoparticles
Fig. 1 Typical voltammetric curves at Au, Ag and Au/Ag nanoparticles modified
electrodes in a 0.1 mol/L NaOH solution in the presence of 5 mmol/L glucose (a, b
and c, respectively)
The result proved that Au-Ag bimetallic nanoparticles had a better
catalytic ability of glucose than Au nanoparticles.
M.Tominaga, et al. J. Electroanal. Chem. 2006, 590, 37.
1. Introduction
1.3 Cu-Au bimetallic nanoparticles
Fig. 2. Snapshots for the Cu-Au cluster configurations.
(Shell structure. Dark atoms, gold; light atoms, copper)
J. L. R. López, et.al. Appl. Surf. Sci. 2003, 219: 56.
1. Introduction
1.4 The Research Idea of My Project
Cu
Cu
Cu
Au
Cu+
Cu
Cu
-e
+e
Cu
Cu
+
Cu+
Cu
Cu+
Cu+
-e
Cu+
Au
Cu
Cu Cu Cu
HO
Cu+
+
Cu
+e
+
2+
Cu
Cu2+
Cu2+
2+
Cu
2+
Au
Cu
Cu2+
Cu+
2+
Cu2+Cu2+Cu
O
NH2
- 2e
+ 2e
HO
Cu2+
O
A Mechanism of Couple Reaction (偶联反应)
NH2
2. Results and Discussion
2.1 Prepare Cu-Au nanoparticles by sol-gel method
H2C
COONa
COONa
HO
C
COONa
+
4 HAuCl4
+
5 H2O
+
3
4 Au
+ 16 HCl
+ 6 Cu
+ 12 HCl
COOH
H2C
COONa
H2C
COONa
COONa
HO
C
COONa
+ 6CuCl2
+
5 H2O
3
COOH
H2C
COONa
Based on the result of atomic absorption spectrophotometer,
the Cu and Au were nearly all been reduced. And the Cu-Au
bimetallic nanoparticles was made up of approximately 50% of
each component.
2. Results and Discussion
2.2 UV-vis spectrum
Fig. 3. The UV-vis spectrums of Au (a) and Cu-Au (b) colloidal nanoparticles.
The two spectrums were greatly similar to each other and had
the surface plasma resonance absorption of nanometer-size
metallic gold particles correspond to a core-shell configuration.
2. Results and Discussion
2.3 Atomic force microscopy images
Fig. 4. Atomic force microscopy images of Cu-Au colloidal bimetallic nanoparticles.
The Cu-Au nanoparticles had an average diameter of 72 nm.
2. Results and Discussion
2.4 Cyclic voltammetry in blank PBS
Fig. 5. The cyclic voltammograms of bare gold electrode (a) and Cu-Au metallic
Nanoparticles modified gold electrode (b) in 0.02 mol/L PBS (pH 7.0) .
Two couples of irreversible redox peaks appeared at - 0.143 V,
+ 0.022 V, + 0.184 V and + 0.501 V correspond to two redox
reaction of Cu element inside the Cu-Au nanoparticles.
2. Results and Discussion
2.5 Electrocatalytic oxidation of dopamine
Fig. 6. Cyclic voltammograms of dopamine on bare gold electrode (a), pristine gold
nanoparticles modified gold electrode (b) and Cu-Au metallic nanoparticles modified
gold electrode (c).
The Cu-Au metallic nanoparticles modified electrode had a
better catalytic ability of dopamine than pristine gold
nanoparticles modified electrode .
2. Results and Discussion
2.6 Interference of ascorbic acid
(A)
(B)
Fig. 7. Cyclic voltammograms (A) and differential pulse voltammograms (B) of
ascorbic acid on the Cu-Au nanoparticles modified electrode.
The interference of ascorbic acid could be eliminate effectively.
2. Results and Discussion
2.7 Differential pulse voltammograms of dopamine
Fig. 8. Differential pulse voltammograms of dopamine on the Cu-Au metallic
nanoparticles modified gold electrode.
The determination method of dopamine had a linear range of
5.0×10-7 to 6.7×10-5 mol/L with a detection limit of 5.2×10-8
mol/L.
2. Results and Discussion
2.8 Injection samples test
Table 1 Determination results of DA in injection samples
Indicated
Samples
（mg·mL-1）
1
2
3
10.0
10.0
10.0
Experimental
（mg·mL-1）
R.S.D.(%)
(n=5)
9.9
10.1
9.8
3.5
2.8
4.1
Recovery
(%)
99
101
98
The method could be efficiently applied to the determination of
dopamine in injection samples.
3. Conclusion
The Cu-Au bimetallic colloidal nanoparticles were
synthesized simple, and characterized by atomic force
microscopy, atomic absorb spectrometry and UV-vis. And the
results demonstrated that the nanoparticles had a core-shell
configuration. And the electrochemical properties of the
nanoparticles modified electrode showed that the Cu inside
the nanoparticles could act as a redox center and this
advantage could enhance the electrocatalytical oxidation
performance toward dopamine of the modified electrode. And
the modified electrode could eliminate the interference of
ascorbic acid. This proposed feasible method is promising for
the determination of dopamine in injection samples.
4. Production
[1] Xianguang Chen, Xiaoyong Zou.
Electroanalyisis, 2007. Under review.
[2] 陈贤光，钱莹，张素娟，邹小勇. 化学学报，
2007，65（4）：337-343.（SCI收录）
[3] 陈贤光，王壬，赵国芳，邹小勇. 分析化学，
2006，34（8）：1063-1067. （SCI-E收录）
[4] 陈贤光，张素娟，欧阳良琪，邹小勇. 分析试验
室，2007，26（4）：30-33.
致谢
感谢邹小勇教授对本人的指导。
感谢国家自然科学基金（Nos.
20475068, 20575082）和中山大学
学生科研基金对本课题的资助。

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