Flow injection biamperometry was extended to irreversible couple systems. For the biamperometry, the essential condition is the coexistence of two reactants, with opposite electrode reaction, of two independent and ir...Flow injection biamperometry was extended to irreversible couple systems. For the biamperometry, the essential condition is the coexistence of two reactants, with opposite electrode reaction, of two independent and irreversible couples in the same system. The system can be skillfully constructed with analyte by choosing such a reactant of one couple as its standard redox potential which was better closed to that of the analyte as nearly as possible. In the chosen system, provided the real potentials of the two working electrodes have exceeded the deposition potential of two reactants by imposing a suitable potential difference Δ E between these two electrodes, faradic current i will flow through circuit. When the concentration of the chosen reactant remains larger constant, the circuit current i will be linearly proportional to the analyte of interest over certain concentration range. To verify the feasibility of the biamperometry, three systems of the dissolved oxygen separately with ascorbic acid, hydrazine chloride and hydroxyamine chloride were examed. In phosphate buffer(pH 6.9) solution containing the dissolved oxygen, using two activated platinum wire working electrodes imposed by potential difference Δ E 0 0 V, the circuit current i was linearly proportional to these three analytes in the concentration range of 1×10 -5 —1×10 -3 mol/L for ascorbic acid, 1×10 -6 —1×10 -4 mol/L for hydrazine chloride and hydroxyamine chloride, respectively. [WT5HZ]展开更多
Adsorptive voltammetric behavior of resveratrol at a silver electrode was investigated. And based on this, a linear scan voltammetry for determination of resveratrol had been found. The adsorption corresponded to the ...Adsorptive voltammetric behavior of resveratrol at a silver electrode was investigated. And based on this, a linear scan voltammetry for determination of resveratrol had been found. The adsorption corresponded to the Langmuir type isotherm curve, and the free energy of adsorption was caculated to be -46.21 kJ/mol at 298 K. The electrochemical parameters such as charge transfer coefficient α and standard electron transfer rate constant ks were estimated. In 0.2 mol/L KNO3+1.2×10 -4 mol/L KCl solution, resveratrol can give a sensitive anode peak at potential about 0.29 V（vs. SCE）. The linear range between the peak current and the concentration of resveratrol is 2.0×10 -9 to 1.0×10 -8 mol/L and 1.0×10 -8 to 9.0×10 -8 mol/L, respectively. The detection limit is 4.0×10 -10 mol/L. The method had been applied to the determination of resveratrol in wine.展开更多
文摘Flow injection biamperometry was extended to irreversible couple systems. For the biamperometry, the essential condition is the coexistence of two reactants, with opposite electrode reaction, of two independent and irreversible couples in the same system. The system can be skillfully constructed with analyte by choosing such a reactant of one couple as its standard redox potential which was better closed to that of the analyte as nearly as possible. In the chosen system, provided the real potentials of the two working electrodes have exceeded the deposition potential of two reactants by imposing a suitable potential difference Δ E between these two electrodes, faradic current i will flow through circuit. When the concentration of the chosen reactant remains larger constant, the circuit current i will be linearly proportional to the analyte of interest over certain concentration range. To verify the feasibility of the biamperometry, three systems of the dissolved oxygen separately with ascorbic acid, hydrazine chloride and hydroxyamine chloride were examed. In phosphate buffer(pH 6.9) solution containing the dissolved oxygen, using two activated platinum wire working electrodes imposed by potential difference Δ E 0 0 V, the circuit current i was linearly proportional to these three analytes in the concentration range of 1×10 -5 —1×10 -3 mol/L for ascorbic acid, 1×10 -6 —1×10 -4 mol/L for hydrazine chloride and hydroxyamine chloride, respectively. [WT5HZ]
文摘Adsorptive voltammetric behavior of resveratrol at a silver electrode was investigated. And based on this, a linear scan voltammetry for determination of resveratrol had been found. The adsorption corresponded to the Langmuir type isotherm curve, and the free energy of adsorption was caculated to be -46.21 kJ/mol at 298 K. The electrochemical parameters such as charge transfer coefficient α and standard electron transfer rate constant ks were estimated. In 0.2 mol/L KNO3+1.2×10 -4 mol/L KCl solution, resveratrol can give a sensitive anode peak at potential about 0.29 V（vs. SCE）. The linear range between the peak current and the concentration of resveratrol is 2.0×10 -9 to 1.0×10 -8 mol/L and 1.0×10 -8 to 9.0×10 -8 mol/L, respectively. The detection limit is 4.0×10 -10 mol/L. The method had been applied to the determination of resveratrol in wine.
