A novel flow-injection irreversible biamperometric method is described for the direct determination of iodide. The method is based on electrochemical oxidation of iodide at the gold electrode and the reduction of perm...A novel flow-injection irreversible biamperometric method is described for the direct determination of iodide. The method is based on electrochemical oxidation of iodide at the gold electrode and the reduction of permanganate at the platinum electrode to form an irreversible biamperometric detection system. Under the applied potential difference of 0 V, in the 0.05 mol/L sulfuric acid, iodidecan be determined over the range 4.00×10^-7-1.00×10^-5 mol/L with a sampling frequency of 120 samples per hour. The detection limit for I- is 3.0×10^-7 mol/L and the RSD for 40 replicate determinations of 4.0×10^-5 mol/L potassium iodide is 1.68%. The new method was applied to the analysis of iodide in table salt with satisfactory results.展开更多
A flow injection irreversible biamperometric method for the determination of chlorogenic acid is described. The proposed method is based on the electrochemical oxidation of chlorogenic acid at pretreated platinum elec...A flow injection irreversible biamperometric method for the determination of chlorogenic acid is described. The proposed method is based on the electrochemical oxidation of chlorogenic acid at pretreated platinum electrode and the reduction of permanganate at another electrode to form an irreversible biamperometric detection system. Under the external potential difference （z^v） of 0 V, in the 0.05 mol/L sulfuric acid, chlorogenic acid can be determined over the range 0.8-120 mg/L with a sample measurement frequency of 80 samples/h. The detection limit is 0.18 mg/L. The proposed method exhibits the satisfactory reproducibility with a relative standard derivation （R.S.D.） of 2.21% for 19 successive determinations of 40 mg/L.展开更多
Based on the electrocatalytic oxidation of levodopa at gold electrode and the reduction of permanganate at platinum electrode, a novel flow injection irreversible biamperometric method is developed for the determinati...Based on the electrocatalytic oxidation of levodopa at gold electrode and the reduction of permanganate at platinum electrode, a novel flow injection irreversible biamperometric method is developed for the determination of levodopa under the potential difference of 0 V imposed between two electrodes. In H2SO4 solution, the linear relationships between currents and the concentrations of levodopa are obtained in the range from 0.04 mg/L to 20 mg/L with the detection limit of 0.012 mg/L. The proposed method is applied to the determination of levodopa in pharmaceutical preparations.展开更多
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
基金support of the Guangxi Science Fund For Youth(No.0135003)Guangxi Universities One Hundred Young-middle Scholar Fund for the present work.
文摘A novel flow-injection irreversible biamperometric method is described for the direct determination of iodide. The method is based on electrochemical oxidation of iodide at the gold electrode and the reduction of permanganate at the platinum electrode to form an irreversible biamperometric detection system. Under the applied potential difference of 0 V, in the 0.05 mol/L sulfuric acid, iodidecan be determined over the range 4.00×10^-7-1.00×10^-5 mol/L with a sampling frequency of 120 samples per hour. The detection limit for I- is 3.0×10^-7 mol/L and the RSD for 40 replicate determinations of 4.0×10^-5 mol/L potassium iodide is 1.68%. The new method was applied to the analysis of iodide in table salt with satisfactory results.
基金the National Natural Science Foundation of China （No. 20665001） Guangxi Science Fund （No. 0640029） Innovation Project of Guangxi Graduate Education （No. 2006105930502m33）.
文摘A flow injection irreversible biamperometric method for the determination of chlorogenic acid is described. The proposed method is based on the electrochemical oxidation of chlorogenic acid at pretreated platinum electrode and the reduction of permanganate at another electrode to form an irreversible biamperometric detection system. Under the external potential difference （z^v） of 0 V, in the 0.05 mol/L sulfuric acid, chlorogenic acid can be determined over the range 0.8-120 mg/L with a sample measurement frequency of 80 samples/h. The detection limit is 0.18 mg/L. The proposed method exhibits the satisfactory reproducibility with a relative standard derivation （R.S.D.） of 2.21% for 19 successive determinations of 40 mg/L.
基金Thanks for the fmancial support of National Natural Science Foundation of China （No. 20665001）；Guangxi Science Fund （No. 0640029） and Master Fund of Guangxi University of Technology.
文摘Based on the electrocatalytic oxidation of levodopa at gold electrode and the reduction of permanganate at platinum electrode, a novel flow injection irreversible biamperometric method is developed for the determination of levodopa under the potential difference of 0 V imposed between two electrodes. In H2SO4 solution, the linear relationships between currents and the concentrations of levodopa are obtained in the range from 0.04 mg/L to 20 mg/L with the detection limit of 0.012 mg/L. The proposed method is applied to the determination of levodopa in pharmaceutical preparations.
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]
