Electrochemical behaviours of Europium-ferrocene derivative complex chemically modified electrodes were studied in the paper. Various factors which affect the voltammetry of the thin film modified electrodes, and the...Electrochemical behaviours of Europium-ferrocene derivative complex chemically modified electrodes were studied in the paper. Various factors which affect the voltammetry of the thin film modified electrodes, and the charge transport process of the thin film electrode were discussed. Size of the hydrated anion (counter ion), concentration of the electrolyte, swelling property of the film in the solvent and thickness of the film have significant effects on the voltammetry of the thin film electrode. Electrochemical behaviours of europium-ferrocene derivative compelx chemically modified electrode were studied in an aqueous solution. When scan ning between 0-0.8 V (vs. SCE), experimental results indicate that the chemically modified electrode has good stability and reproducibility. The apparent rate constant of electrode reaction is deteminedd to be 6.7×10-1 s-1.展开更多
The electrochemical behaviors of Eu3+ on Eastman AQ-29D/glassy carbon(GC) chemically modified electrode(CME) were studied. It was found that the reduction-oxidation process of Eu3+ is in a semi-infinite condition in 0...The electrochemical behaviors of Eu3+ on Eastman AQ-29D/glassy carbon(GC) chemically modified electrode(CME) were studied. It was found that the reduction-oxidation process of Eu3+ is in a semi-infinite condition in 0.1 mol/L NaCIO4 supporting electrolyte(pH 4.4). The calibration curve was linear over the range 1.0×10-7 to 1.0×105 mol/L of Eu3+.The charge transport apparent diffusion coefficient of Eu3+ in the polymer film was determined to be(3.2±1.1)×10-11cm2/s by chronocoulometry.展开更多
Herein, a convenient method based on a fullerene/multiwalled carbon nanotube/Nafion modified glassy carbon electrode (fullerene/MWCNT/Naf/GCE) for the electrochemical determination of caffeine (CAF) is reported. Cycli...Herein, a convenient method based on a fullerene/multiwalled carbon nanotube/Nafion modified glassy carbon electrode (fullerene/MWCNT/Naf/GCE) for the electrochemical determination of caffeine (CAF) is reported. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to study ionic exchange properties and conductivity the proposed electrode using [Fe(CN)6]3-/4- redox couple. Caffeine gave an irreversible oxidation peak around +1.33 V (vs. Ag/AgCl reference electrode) in HClO4 (pH 1). The linear dependence of the peak current with the square root of the scan rate showed that the electron transfer process is controlled by diffusion. After optimization of key analytical parameters involved in differential pulse voltammetry (DPV), the oxidation peak current varied linearly with CAF concentration in the range of 10 to 1000 μM. A detection limit of 7.289 × 10-8 M (S/N = 3) was found. Kinetic and chronocoulometric studies were also performed to characterize the diffusion of CAF. The developed electrode exhibited good stability and was easily regenerated. The influence of some potential interfering compounds such as dopamine, uric acid, glucose and sulfite ions on the anodic peak current of CAF was also examined. The proposed method was successfully employed in the determination of CAF in some commercial drugs.展开更多
The electrocatalytic oxidation of methanol at the platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes (Eu-Fe film) was investigated for the first time by cyclic voltammetry.Compared with the bar...The electrocatalytic oxidation of methanol at the platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes (Eu-Fe film) was investigated for the first time by cyclic voltammetry.Compared with the bare platinum electrode,the results showed that the modified electrode had excellent electrocatalytic activity for the oxidation of methanol;the oxidation peak potential shifted more negatively and the peak current increased about twenty times.The electrooxidation of methanol at the modified elect...展开更多
A homogeneous dispersion of multiwall carbon nanotubes(MWNT) was achieved by dispersing MWNT into 0.1% Nafion ethanol solution, and a uniform cast film at a glassy carbon electrode(GCE) was obtained via solvent evapor...A homogeneous dispersion of multiwall carbon nanotubes(MWNT) was achieved by dispersing MWNT into 0.1% Nafion ethanol solution, and a uniform cast film at a glassy carbon electrode(GCE) was obtained via solvent evaporation of the MWNT dispersion. A reversible two-electron redox reaction of dopamine was observed at the MWNT-Nafion modified GCE. In comparison with a bare GCE and a Nafion-modified GCE, MWNT-Nafion modified GCE has a higher sensitivity for dopamine. This modified GCE has an excellent selectivity towards dopamine even in the presence of high concentration ascorbic acid(AA) and uric acid(UA) since AA and UA have no observable electrochemical responses at the modified GCE. The electrochemical behavior of dopamine was closely related to the pH of the buffer solution. The oxidation peak current was proportional to the concentration of dopamine over the range from 5×10 -8 to \{1×\}10 -6 mol/L, and a detection limit of 2.5×10 -9 mol/L was obtained after 3 min open-circuit accumulation. The dispersion and morphology of MWNT-Nafion film were investigated by transmission electron microscopy(TEM).展开更多
文摘Electrochemical behaviours of Europium-ferrocene derivative complex chemically modified electrodes were studied in the paper. Various factors which affect the voltammetry of the thin film modified electrodes, and the charge transport process of the thin film electrode were discussed. Size of the hydrated anion (counter ion), concentration of the electrolyte, swelling property of the film in the solvent and thickness of the film have significant effects on the voltammetry of the thin film electrode. Electrochemical behaviours of europium-ferrocene derivative compelx chemically modified electrode were studied in an aqueous solution. When scan ning between 0-0.8 V (vs. SCE), experimental results indicate that the chemically modified electrode has good stability and reproducibility. The apparent rate constant of electrode reaction is deteminedd to be 6.7×10-1 s-1.
文摘The electrochemical behaviors of Eu3+ on Eastman AQ-29D/glassy carbon(GC) chemically modified electrode(CME) were studied. It was found that the reduction-oxidation process of Eu3+ is in a semi-infinite condition in 0.1 mol/L NaCIO4 supporting electrolyte(pH 4.4). The calibration curve was linear over the range 1.0×10-7 to 1.0×105 mol/L of Eu3+.The charge transport apparent diffusion coefficient of Eu3+ in the polymer film was determined to be(3.2±1.1)×10-11cm2/s by chronocoulometry.
文摘Herein, a convenient method based on a fullerene/multiwalled carbon nanotube/Nafion modified glassy carbon electrode (fullerene/MWCNT/Naf/GCE) for the electrochemical determination of caffeine (CAF) is reported. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to study ionic exchange properties and conductivity the proposed electrode using [Fe(CN)6]3-/4- redox couple. Caffeine gave an irreversible oxidation peak around +1.33 V (vs. Ag/AgCl reference electrode) in HClO4 (pH 1). The linear dependence of the peak current with the square root of the scan rate showed that the electron transfer process is controlled by diffusion. After optimization of key analytical parameters involved in differential pulse voltammetry (DPV), the oxidation peak current varied linearly with CAF concentration in the range of 10 to 1000 μM. A detection limit of 7.289 × 10-8 M (S/N = 3) was found. Kinetic and chronocoulometric studies were also performed to characterize the diffusion of CAF. The developed electrode exhibited good stability and was easily regenerated. The influence of some potential interfering compounds such as dopamine, uric acid, glucose and sulfite ions on the anodic peak current of CAF was also examined. The proposed method was successfully employed in the determination of CAF in some commercial drugs.
基金the Project of Natural Science Foundation of Gansu Province of their financial supports(No. 096RJZA117)
文摘The electrocatalytic oxidation of methanol at the platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes (Eu-Fe film) was investigated for the first time by cyclic voltammetry.Compared with the bare platinum electrode,the results showed that the modified electrode had excellent electrocatalytic activity for the oxidation of methanol;the oxidation peak potential shifted more negatively and the peak current increased about twenty times.The electrooxidation of methanol at the modified elect...
文摘A homogeneous dispersion of multiwall carbon nanotubes(MWNT) was achieved by dispersing MWNT into 0.1% Nafion ethanol solution, and a uniform cast film at a glassy carbon electrode(GCE) was obtained via solvent evaporation of the MWNT dispersion. A reversible two-electron redox reaction of dopamine was observed at the MWNT-Nafion modified GCE. In comparison with a bare GCE and a Nafion-modified GCE, MWNT-Nafion modified GCE has a higher sensitivity for dopamine. This modified GCE has an excellent selectivity towards dopamine even in the presence of high concentration ascorbic acid(AA) and uric acid(UA) since AA and UA have no observable electrochemical responses at the modified GCE. The electrochemical behavior of dopamine was closely related to the pH of the buffer solution. The oxidation peak current was proportional to the concentration of dopamine over the range from 5×10 -8 to \{1×\}10 -6 mol/L, and a detection limit of 2.5×10 -9 mol/L was obtained after 3 min open-circuit accumulation. The dispersion and morphology of MWNT-Nafion film were investigated by transmission electron microscopy(TEM).
