Laboratory Construction of Copper-Selective Electrode

Copper ion selective electrode was constructed and the performance of membranes prepared from different methods was compared. Removal of oxygen from the system in the preparation of electrode membrane was suggested. The behavior of the membrane, the working concentration range, response time, internal filling solution and treatment of the electrode were discussed.     

Determination of Citrate Ions by Potentiometric Titration with a Copper-Selective Electrode in Monitoring the Production of Citric Acid

A simple and rapid procedure was developed for the potentiometric titration of citrate ions in fermented solutions from citric acid production with the use of a copper-selective electrode.     

Direct Observation of Dye-Containing Amphiphilic Copolymer in the Honeycomb-Patterned Film

Honeycomb-patterned film was prepared by casting chloroform solution of hydrophobic polymer and dye-containing amphiphilic copolymer under humid conditions. The confocal laser scanning microscopy image shows that amphiphilic copolymer is localized around the pores of the honeycomb-patterned film.     

Electrode Response of a Fluoride-Selective Electrode in Buffer Solutions of Potential-Determining Ions

The electrode response of a fluoride-selective electrode was studied in HNO₃ and Al(NO₃)₃ solutions of different concentrations and ionic strengths. We have substantiated the ion-exchange mechanism of the formation of fluoride ions in the near-membrane layer of blank buffer solutions and found that their concentration (⁰) was (4.0 ± 0.4) × 10^–6 M.     

Ammonia Electrode Performance in Deuterium Oxide Solutions

Abstract

Response characteristics of the ammonia gassensing membrane electrode have been evaluated in deuterium oxide solutions. Results indicate no significant differences in electrode slope, recovery time, and standard deviation of the fit for the calibration line. Only slight differences in response times, limit of detection, baseline potential and position of the calibration line have been found. Overall, steady-state and dynamic measurements in deuterium oxide solutions are possible with this electrode.     

纳米TiO2电极在不同介质中的电化学行为

纳米电极;电催化;纳米TiO2电极在不同介质中的电化学行为;循环伏安法;循环方波伏安法     

Electrode Response and Detection Limits of a Fluoride-Selective Electrode in Anionic Buffer Solutions

It was found that electrode response and the chemical nature of the background activity appearance of a fluoride-selective electrode are identical in nonbuffered solutions and anionic complexing media. The background activity was assessed in dipotassium hydrogen citrate solutions of different concentrations. At zero ionic strength, the background activity was constant and equal to _{I = 0} = (4.0 ± 0.4) × 10^–6 M at 25.0 ± 0.1°C. Detection limits were calculated for different confidence levels. It was shown that a variation in the nature and concentration of masking ligands cannot cause a change in performance characteristics of the electrode and of the method.     

Electrode Kinetics of Concentrated Sulfide Ion in Basic Solutions

The diffusion coefficients of sulfide ion in 5 M NaOH solution with concentrations of (0.02–0.3)M at temperatures 24–50°C were determined using a rotating-ring-disc Pt electrode to be (0.5–2.0)×10^?5 cm₂/sec. The reaction order of the sulfide oxidation to sulfur was calculated to be 0.42 which implies one-electron transfer as the rate-limiting step and the reaction rate constant was found to be k_f=2.57×10^?5 exp(-0.14ZF_π/RT).     

铂电极上溶液酸碱性的电位溶出法响应

提出了一个广谱测定强酸、强碱溶液浓度的方法。用铂电极作工作电极，电位溶出法对溶液酸碱性产生响应。通过调节沉积时间和沉积电位，利用电位溶出法可以检测溶液酸、大致 的浓度范围为2．5mol/L H^ -1.0mol/L OH^-。详细研究了不同测定范围的实验条件，以及溶出过程的响应机理。在不同酸碱性溶液中电沉积产生的氢吸附于电极表面，溶出过程中被溶液中的氧氧化成氢离子，从而产生电位平台。该平台的出现还与随后的电极表面金属／金属氧化物电对电位值有关。     

Behavior of Glassy Carbon Paste Electrode in Flowing Methanolic Solutions

Carbon paste electrodes are often used for electrochemical determinations, but their application in media with high content of organic solvents, particularly in HPLC, is limited by their low stability. The work presented here examines the effect of a moving methanol‐containing solution on a glassy carbon paste electrode by studying its electrochemical behavior in relation to the period of contact and methanol content in the solution. In combination with microscopic observation of the paste surface it can be concluded that the electrode is affected by the methanolic solution and the surface roughness increases, resulting in the stable state compatible with measurements in highly methanolic solutions.     

碱性溶液中锌电极缓蚀的研究

研究了硝酸铅（Pb(NO3)2）和十二烷基苯磺酸钠（SDBS）及二者组成的复合添加剂对在3mol•L-1 KOH溶液中锌电极电化学行为的影响, 结果表明:两种添加剂均具有一定的缓蚀作用,而其复合添加剂的协同效应、缓蚀效果最佳.     

Adsorption Isotherm Accounting for the Electrode Elasticity: Special Solutions

The single-phase adsorption on a solid electrode out of a dilute solution is investigated. As a continuation of the previous paper, on the basis of the complete electrocapillarity equation, an adsorption isotherm equation is derived and supplemented by equations of compatibility of the physical quantities. The equations contain a new parameter, , which is a derivative of the dimensionless surface adsorbate concentration by the relative variation of the electrode surface area. Their solution is obtained in relation to the dimensionless charge density of the electrode surface q for the case of = (). As a result of employing a linear model for q by , the problem of determination of the unknown model functions is reduced to common differential equations that use the capacitance or estance curves as the boundary conditions. In the first case, we suggest to calculate the unknown integration parameter by the method of mathematical optimization, employing coulometric data.     

Modifying Electrode Properties of Carbon-Fiber Materials by Electrolysis in Aqueous Solutions

The possibility of applying electrolysis in aqueous solution for the modification of electrode properties of carbon-fiber materials (CFM) is examined. It is shown that the cathodic and anodic polarization of CFM in solutions of acids and alkalis alters the state of the surface of fibers that constitute CFM, which is manifested in a change of the CFM electrode potential. The possibility of changing the CFM electroconductivity by an electrode treatment is demonstrated. This makes it possible to design electrodes with electroconductivity that varies over the electrode's thickness. The latter is of importance for both developing non-isoelectroconducting three-dimensional electrodes with a rigid matrix and comprehending operation principles of carbon-fiber electrodes. The obtained experimental data conform to the calculated dependences, specifically, profiles of electroconductivity and polarization over the electrode thickness are similar.     

Characteristics of Fluoride-Selective Electrode with Uranyl Salophen Receptors in Aqueous Solutions

A fluoride-selective electrode with uranyl salophen receptors is developed. Its basic electrode characteristics are the concentration range 10^-4-10^-1 M and the slope of the electrode function 56 mV/pF^-. The electrode shows a high fluoride selectivity in the presence of such interfering anions as sulfate, chloride, and nitrate.     

Electrochemical Processes of Sulfide in NaCl Electrolyte Solutions on Mercury Electrode

The electrochemical processes of sulfide in NaCl electrolyte solutions were studied using stripping cyclic voltammetry, differential capacity and chronoamperometric measurements. Some new effects were observed and are here discussed. At potentials around ?0.1 to ?0.3 V a pair of Faradaic adsorptive peaks, which can only be observed in the presence of chloride, is attributed to the formation of HgCl ion from the deposited layer of HgS. A second pair of peaks of purely capacitive character was observed at ?0.4 V. This is the result of the reorientation and partial desorption or transformation of HgS layers. The formation and dissolution of HgS layers on mercury has been well investigated previously. We observed some new effects after depositing approximately ten layers of HgS and attributed this to the formation of polysulfides at positive potentials.     

锌电极有机复配缓蚀剂的性能研究

应用极化曲线、表面张力、放电实验和SEM等测试方法,研究了阴离子表面活性剂十二烷基苯磺酸钠(简称SDBS)和非离子表面活性剂吐温-20(简称Tween)之复配体系(简称ST)在碱性介质中对锌电极电化学性能的影响及其作用机理.实验表明,复配缓蚀剂ST具有比单一添加SDBS或Tween更高的缓蚀效率,并且二者具有明显的协同作用,Tween在复配体系中的作用是使活性物质于锌电极表面的临界胶团浓度显著降低,吸附分布更加均匀.从而可更有效的抑制锌电极腐蚀,改善锌电极的表观形貌,达到延迟钝化的效果,使活性物质利用率得到显著提高.     

Effect of Anodic Polarization of Fibrous Carbon Electrode in Alkaline and Acid Solutions on the Distribution of Electrical Conductivity across the Electrode Thickness

The effect exerted by anodic treatment of electrodes with varied thickness, made of NT-1 low-conductivity carbonized material, in 0.07 M KOH and 0.25 M H₂SO₄ solutions on the distribution of the electrical conductivity across the electrode thickness at various anodic polarization conditions was studied.     

电化学改性石墨电极在不同溶液中的准电容及电催化性能

通过循环电流阶跃方法制备电化学改性石墨电极(MGE), 用循环伏安(CV)法评价了MGE在酸性和中性溶液中的准电容特性, 并研究了其在HCl和HNO₃溶液中的电催化作用. 结果表明: 在酸性条件下, MGE在H₂SO₄溶液中具有佷好的准电容特性, 比电容高达1.730 F·cm^-2; 在HCl溶液中也具有很好的准电容特性, 且MGE对析氯反应具有一定的电催化活性(起始析氯电位负移238 mV), 使其电位窗变窄; 在HNO₃溶液中没有准电容特性, 而MGE对NO₃^-离子的还原反应具有极强的电催化能力. 当电介质由酸性变为中性时, 虽然其峰电流密度有所降低, 但电位窗大幅度增宽, 意味着MGE在中性体系中的能量密度比酸性体系会有较大的提高.