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）. C. C. Felix, R. C. Sealy. J. Am. Chem. Soc. , 1981, 103: 2831. 1. Introduction 1.2 Bimetallic nanoparticles.
C. C. Felix, R. C. Sealy. J. Am. Chem. Soc. , 1981, 103: 2831.
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.
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.
A Mechanism of Couple Reaction (偶联反应)
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.
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.
Fig. 4. Atomic force microscopy images of Cu-Au colloidal bimetallic nanoparticles.
The Cu-Au nanoparticles had an average diameter of 72 nm.
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.
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 .
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.
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.
Table 1 Determination results of DA in injection samples
The method could be efficiently applied to the determination of dopamine in injection samples.
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.
 Xianguang Chen, Xiaoyong Zou.
Electroanalyisis, 2007. Under review.
 陈贤光，钱莹，张素娟，邹小勇. 化学学报，
 陈贤光，王壬，赵国芳，邹小勇. 分析化学，
 陈贤光，张素娟，欧阳良琪，邹小勇. 分析试验