Potentiostat

About: Potentiostat is a research topic. Over the lifetime, 1356 publications have been published within this topic receiving 21170 citations.

Cyclic Voltammetry: Simulation And Analysis Of Reaction Mechanisms

Abstract: Useful Equations 1. The Reduction Potential and Electrode Kinetics 1.1 The Reduction Potential 1.2 Electrode Kinetics References 2. The Cyclic Voltammetric Experiment 2.1 An Overview 2.2 The Electrochemical Cell 2.3 Electrochemical Mechanisms: E&C Notation 2.4 Distortions of the Faradaic Response 2.5 Microelectrodes and Fast Scan Voltammetry 2.6 Potential Step Methods and Cyclic Voltammetry 2.7 Construction of a Fast Potentiostat 2.8 Determination of the Number of Electrons References 3. A Survey of Electrochemical Mechanisms 3.1 The CE Mechanism 3.2 Multielectron Transfer 3.3 Protonations at Equilibrium 3.4 Catalytic Mechanisms 3.5 The Reduction of Nitrobenzoic Acid 3.6 Reduction of the Nit rosonium Cation and Its Complexes 3.7 Reactivity of 17--, 18--, and 19--Electron Tungsten Complexes 3.8 Mechanisms Involving Adsorption References 4. The Simulation of Electrochemical Experiments 4.1 The Discretized Diffusion Equation 4.2 Evaluation of the Boundary Conditions 4.3 Dimensionless Units 4.4 Solution Chemical Kinetics 4.5 A Sample Simulation Program References 5. CVSIM: A General Program for the Simulation of Cyclic Voltammetry Experiments 5.1 An Overview of CVSIM 5.2 Extensions of the Simulation Method 5.3 Accuracy of Simulations 5.4 Installation and Use of CVSIM and CVGRAF 5.5 Examples References 6. CVFIT: Simplex Data Analysis with CVSIM 6.1 CVFIT: Simplex Data Analysis with CVSIM 6.2 Instructions for the use of CVFIT 6.3 A Prototype Analysis: The EC Mechanism 6.4 Some Final Comments on Simulation Analysis References Appendix: Summary of Instructions for CVSIM, CVGRAF, CVFIT, and DSTEP Index

Analyte-controlled liquid delivery device and analyte monitor

Abstract: A liquid delivery device comprising a housing having a lower surface for application to the skin of a subject and having a reservoir and a gas generation chamber therein separated by a displaceable membrane. Gas generated by an electrolytic cell under the control of a microprocessor causes the gas generation chamber to expand and the reservoir to contract, thereby discharging a liquid drug, such as insulin, from the reservoir via a hollow delivery needle extending from the lower surface. The delivery needle and a sensor needle both extend from the lower surface a sufficient distance so as to penetrate through the epidermis and into the dermis when the housing is pressed against the skin. The sensor needle has an enzymatic coating for the detection of an analyte, such as glucose in the subject's plasma. The delivery needle is made of platinum-iridium, and a current passes between the needles and a potentiostat circuit according to the amount of glucose detected. A reference electrode (silver/silver chloride) which rests against the subject's skin increases the accuracy of the glucose measurement. The current through the potentiostat circuit is measured by a voltmeter and a signal from the voltmeter is amplified and communicated to the microprocessor which determines the correct rate of delivery of the drug on the basis of the level of analyte detected in the subject's plasma.

Using activated carbon electrode in electrosorptive deionisation of brackish water

Abstract: The electrosorptive deionisation process has been investigated to develop the technology into a system for desalination. Experiments have been conducted in a reactor system and it has been found that the activated carbon has some deionisation capacity due to its very high adsorption capacity and conductivity, so it can be used as an alternative electrode material. Surface modifications have been made to the activated carbon material, including alkaline treatment and loading of titanium dioxide nanoparticles. The specific surface areas (BET), average pore size and total pore volume were analysed by surface area and porosity analyzer. The modified electrode material demonstrated enhanced electrosorption capacity and reduced physical sorption at the pores, so desorption is more efficient. An innovative approach for desorption of the saturated activated carbon electrodes has been tried using ultrasonic vibration and increased temperature, the results of regeneration in water, aided by ultrasonic at 20°C and 50°C are presented as well. Cyclic voltammetry experiments at various scan rates were conducted using a potentiostat to analyse the electrical double-layer capacitance of the activated carbon materials. This preliminary study demonstrated that activated carbon granules have the potential to be cost-effective electrode materials for desalting brackish water. The improvement of the electrosorption efficiency can be achieved by surface modification by chemicals and metal oxide nanoparticles such as TiO2.

Quantitative analysis of reversible diffusion-controlled currents of redox soluble species at interdigitated array electrodes under steady-state conditions

Abstract: Equations for diffusion-controlled currents at interdigitated array electrodes (IDA) were derived analytically for the reversible redox reactions of soluble species under steady-state conditions. The two-dimensional diffusion equation was solved by the Schwarz-Christoffel transformation. Current and concentration distributions were obtained. The total current was expressed by the ratios of the two complete elliptic functions and the geometric widths of the anode, the cathode and the gap. The current at each microband electrode of the IDA depended on the ratios of the three widths rather than the absolute values of the widths. Platinum IDAs were fabricated by photolithography on silicon wafers. The widths of the microband electrodes were 3–10 μm while those of the gap were 2–5 μm. Voltammograms of ferrocene were measured with a dual potentiostat under steady-state conditions. The collection efficiency was ca. 95%. The limiting current agreed with the theoretical prediction.