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Chemical Research in Chinese Universities 2010年第6期26卷 893-898页

作者： WASEEM Amir YAQOOB Mohammad NABI Abdul Department of Chemistry COMSATS Institute of Information Technology Department of Chemistry University of Balochistan

A simple flow injection spectrophotometric method is reported for the determination of cysteine,N-acetyl cysteine and glutathione based on the reduction of Fe（Ⅲ）/ferricyanide,the in situ reduced ions are reacted with unreduced portion of ferricyanide/Fe（Ⅲ） to form soluble Prussian blue,which is monitored at 735 *** calibration graphs are linear in the concentration ranges of（1―100）×10-6 mol/L for cysteine and N-acetyl cysteine,and（1―50）×10-6 mol/L for *** relative standard deviations of 1.8%,2.5% and 1.9% were found for eleven replicate analyses of 5×10-6 mol/L cysteine,N-acetyl cysteine and *** limits of detection（3σ blank） at 5×10-7 mol/L for cysteine,and 3×10-7 mol/L for N-acetyl cysteine and glutathione were *** proposed method allowed 60 injections/*** effects of common substances present in pharmaceuticals and human physiological fluids were *** method was applied to determining cysteine in pharmaceutical formulations with the recoveries in a range of 97% to 106% and the results obtained are agreed well with labeled values.

关键词： Flow injection Spectrophotometry Cysteine Prussian blue Fe(Ⅲ) ferricyanide Pharmaceutical

Flow injection spectrophotometric determination of vitamin E in pharmaceuticals,milk powder and blood serum using potassium ferricyanide-Fe(Ⅲ) detection system

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Chinese Chemical Letters 2010年第6期21卷 712-715页

作者： Saima Jadoon Amir Waseem Mohammad Yaqoob Abdul Nabi Department of Chemistry University of BalochistanQuettaPakistan

A simple and sensitive flow injection spectrophotometric method is reported for the determination of vitamin E using potassium ferricyanide-Fe(Ⅲ) detection *** the presence of vitamin E,Fe(Ⅲ)/ferricyanide *** in situ reduced ions are then reacted with unreduced portion of ferricyanide/Fe(Ⅲ) to make soluble Prussian blue,which is monitored at absorption wavelength of 735 *** calibration graph was obtained in the concentration range of 0.1-40μg mL^(-1).The relative standard deviations (n=4) were in the range of 1.1-3.6%,with limits of detection(3 s blank) of 0.04μg mL^(-1).The proposed method allowed 12 injections h^(-1).The method is applied to determine vitamin E in pharmaceuticals,infant milk and blood serum samples using hexane extraction with the recoveries in the range of 93±3 to 97.5±4%.The method is validated using certified reference materials SRM 968c for blood serum samples.

关键词： Flow injection Spectrophotometry Vitamin E Prussian blue Fe(III) ferricyanide Pharmaceuticals Blood serum

Electrocatalytic Determination of Dopamine in the Presence of Ascorbic Acid by Poly-L-proline and ferricyanide Compound Film Modified Electrode

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Chemical Research in Chinese Universities 2009年第6期25卷 827-831页

作者： CAO Yan-xiu LIU Xing-mei HUANG Hui ZHANG Xue-yu ZHANG Zhi-quan College of Chemistry Jilin University Changchun 130012 P. R. China

A novel biosensor was fabricated by the electrochemical polymerization of poly-L-proline（P-LP） and ferricyanide（FC） to form a compound film on a glassy carbon electrode（GCE）. The compound film modified electrode（P-LP/FC/GCE） shows electrocatalytic activity toward dopamine（DA） in a phosphate buffer solution（PBS, pH = 4.0） with a diminution of the overpotential and an increase in peak current. P-LP/FC/GCE was used to study the electrocatalytic oxidation of DA and ascorbic acid（AA） by means of cyclic voltammetry（CV）, differential pulse voltammetry（DPV） and amperometric i-t curve techniques. The overlapping anodic peaks of DA and AA were resolved into two well-defined voltammetric peaks in CV and DPV with the potential differences of about 200 and 225 mV, respectively. The peak current of DA is linearly change with the concentration of DA in a range of 1 × 10^-7 to 1.14 × 10^-4 mol/L with the correlation coefficient of 0.9997. The detection limit is 4.4~10-8 mol/L（S/N=3）. P-LP/FC/GCE exhibited an excellent selectivity, sensibility and stability for the determination of DA, and can be applied to the determination of dopamine injections with satisfied results.

关键词： L-Proline ferricyanide Dopamine Modified electrode Electropolymerization

Silver dissolution in a novel leaching system: Reaction kinetics study

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International Journal of Minerals,Metallurgy and Materials 2019年第2期26卷 168-177页

作者： Li Xiao Pei-wei Han Yong-liang Wang Guo-yan Fu Zhi Sun Shu-feng Ye State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences University of Chinese Academy of Sciences

Effective silver recovery is usually restricted by either environmental pollution or high recovery costs. To tackle the issues, this study introduces a novel method for the effective recovery of silver by utilizing the alkaline sodium thiosulfate-potassium ferricyanide leaching system. The reaction kinetics of silver dissolution in this system was investigated via the rotating disk electrode technology. The influences of important parameters, including the rotation speed, sodium thiosulfate concentration, potassium ferricyanide concentration, and temperature, on the silver dissolution rate were systematically investigated. The activation energy was measured to be 17.96 kJ·mol^(-1) when the silver dissolution was controlled by a diffusion process. When the silver dissolution was in the region of mixed control, the reaction orders of ferricyanide and thiosulfate were found to be 0.57 and 0.19, respectively, and the reaction orders of ferricyanide and thiosulfate were 0.55 and 0.22, respectively, when the silver dissolution was controlled by surface reaction. This study has great potential for the development of an environmentally friendly silver recovery process from end-of-life products.

关键词： silver recovery thiosulfate ferricyanide dissolution kinetics non-cyanide

On the Criteria of Instability for Electrochemical Systems

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Chinese Journal of Chemistry 2002年第7期20卷 657-662页

作者：李则林任斌牛振江肖小明曾跃田中群 Institute of Physical Chemistry Zhejiang Normal University Jinhua Zhejiang 321004 China Department of Chemistry Hunan Normal University Changsha Hunan 410081 China State Key Laboratory for Physical Chemistry of Solid Surfaces and Department of Chemistry Xiamen University Xiamen Fujian 361005 China

Both cyclic-voltammetry-based and impedance-based experimental criteria thathave been developed recently for the oscil-latory electrochemical systems are critically appraisedwith two typical categories of oscillators. Consistent conclusions can be drawn by the two criteriafor the category of oscillators that involve the coupling of charge transfer mainly with surfacesteps (e.g. ad- and desorption) such as in the electrooxidation of C_1 organic molecules. Whereas,impedance-based criterion is not applicable to the category of oscillators that involve the couplingof charge transfer mainly with mass transfer (e.g. diffusion and convection) such as in theFe(CN)_6^(3-) reduction accompanying periodic hydrogen evolution. The reason is that the negativeimpedance cannot include the feedback information of convection mass transfer induced by thehydrogen evolution. However, both positive and negative nonlinear feedbacks, i. e., thediffusion-limited depletion and convection-enhanced replenishment of the Fe(CN)_6^(3-) surfaceconcentration, that coexist between the bistability, i. e., Fe(CN)_6^(3-) reduction with and withouthydrogen evolution at lower and higher potential sides respectively, are all reflected in thecrossed cyclic voltammo-gram (CCV). It can be concluded that the voltammetry-based criterion (intime domain) is more intuitive, less time-consuming and has a wider range of applications than theimpedance-based one (in frequency domain).

关键词： electrochemical oscillations criteria for instability cyclic voltammograms impedance spectroscopy C_1 organic molecules ferricyanide

Disposable Electrochemical Biosensor for Amperometric Measurement of β-hydroxybutyrate and Total Cholesterol

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稀有金属材料与工程 2006年第A3期35卷 305-308页

作者： Huaqing Li Li Wang Nenggao Rao Dafu Cui Xinxia Cai State Key Laboratory of Transducer Technology Institute of Electronics Chinese Academy of Sciences Beijing 100080 China Graduate School of Chinese Academy of Science Beijing 100080 China

A new type of disposable thin-film amperometric biosensor has been developed for measurement ofβ-hydroxybutyrate and total cholesterol in *** biosensor consists of two plain gold electrodes mounted on a Polyethylene terephthalate (PET) *** reagent solution contains bienzymes (cholesterol oxidase and cholesterol esterase for total cholesterol,β-hydroxybutyrate dehydrogenase and diaphorase forβ-hydroxybutyrate respectively) with mediator (ferricyanide) were absorption at the surface of electrodes coated by electrodepositing platinum *** presence of the mediator lowers the applied potential and eliminates the interference from other oxidizable species enhancing the sensitivity and selectivity of the biosensor without modifying the dynamic parameters of the *** enzymes stably retains in the matrices of platinum black film improving the performance of the mediated *** linearity is observed in the concentration range from 1.0×10^(-4) to 1.0×10^(-2) mM and 1.0×10^(-4) mM to 4.99×10^(-3) mM with sensitivity of 1.958μA/mM and 2.447μA/mM *** optimized biosensor exhibits excellent reproducibility and stability retaining more than 90% of its original activity over a period of one *** simple operation of the biosensor mass-produced at low cost is expected to find clinical application and homecare.

关键词： amperometric β-Hydroxybutyrate total cholesterol ferricyanide platinum black

Disposable Electrochemical Biosensor for Amperometric Measurement of β-hydroxybutyrate and Total Cholesterol

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稀有金属材料与工程 2006年第S3期 305-308页

作者： Huaqing Li~(1,2) Li Wang~1 Nenggao Rao~1 Dafu Cui~1 Xinxia Cai~(1,2) (1.State Key Laboratory of Transducer Technology,Institute of Electronics,Chinese Academy of Sciences,Beijing 100080,China) (2.Graduate School of Chinese Academy of Science,Beijing 100080,China)

A new type of disposable thin-film amperometric biosensor has been developed for measurement ofβ-hydroxybutyrate and total cholesterol in *** biosensor consists of two plain gold electrodes mounted on a Polyethylene terephthalate （PET） *** reagent solution contains bienzymes （cholesterol oxidase and cholesterol esterase for total cholesterol,β-hydroxybutyrate dehydrogenase and diaphorase forβ-hydroxybutyrate respectively） with mediator （ferricyanide） were absorption at the surface of electrodes coated by electrodepositing platinum *** presence of the mediator lowers the applied potential and eliminates the interference from other oxidizable species enhancing the sensitivity and selectivity of the biosensor without modifying the dynamic parameters of the *** enzymes stably retains in the matrices of platinum black film improving the performance of the mediated *** linearity is observed in the concentration range from 1.0×10-4to 1.0×10-2mM and 1.0×10-4mM to 4.99×10-3mM with sensitivity of 1.958μA/mM and 2.447μA/mM *** optimized biosensor exhibits excellent reproducibility and stability retaining more than 90% of its original activity over a period of one *** simple operation of the biosensor mass-produced at low cost is expected to find clinical application and homecare.

关键词： amperometric β-Hydroxybutyrate total cholesterol ferricyanide platinum black