Design and Testing of a Computer-Controlled Square Wave Voltammetry Instrument

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6-1-1987

Design and testing of a computer-controlled square wave voltammetry instrument

Nancy L. Wengenack

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07 Chapter2.Pdf

22 METHODOLOGY 2.1 INTRODUCTION TO ELECTROCHEMICAL TECHNIQUES Electrochemical techniques of analysis involve the measurement of voltage or current. Such methods are concerned with the interplay between solution/electrode interfaces. The methods involve the changes of current, potential and charge as a function of chemical reactions. One or more of the four parameters i.e. potential, current, charge and time can be measured in these techniques and by plotting the graphs of these different parameters in various ways, one can get the desired information. Sensitivity, short analysis time, wide range of temperature, simplicity, use of many solvents are some of the advantages of these methods over the others which makes them useful in kinetic and thermodynamic studies1-3. In general, three electrodes viz., working electrode, the reference electrode, and the counter or auxiliary electrode are used for the measurement in electrochemical techniques. Depending on the combinations of parameters and types of electrodes there are various electrochemical techniques. These include potentiometry, polarography, voltammetry, cyclic voltammetry, chronopotentiometry, linear sweep techniques, amperometry, pulsed techniques etc. These techniques are mainly classified into static and dynamic methods. Static methods are those in which no current passes through the electrode-solution interface and the concentration of analyte species remains constant as in potentiometry. In dynamic methods, a current flows across the electrode-solution interface and the concentration of species changes such as in voltammetry and coulometry4. 2.2 VOLTAMMETRY The field of voltammetry was developed from polarography, which was invented by the Czechoslovakian Chemist Jaroslav Heyrovsky in the early 1920s5. Voltammetry is an electrochemical technique of analysis which includes the measurement of current as a function of applied potential under the conditions that promote polarization of working electrode6.
Convergent Paired Electrochemical Synthesis of New Aminonaphthol Derivatives

www.nature.com/scientificreports OPEN New insights into the electrochemical behavior of acid orange 7: Convergent paired Received: 24 August 2016 Accepted: 29 December 2016 electrochemical synthesis of new Published: 06 February 2017 aminonaphthol derivatives Shima Momeni & Davood Nematollahi Electrochemical behavior of acid orange 7 has been exhaustively studied in aqueous solutions with different pH values, using cyclic voltammetry and constant current coulometry. This study has provided new insights into the mechanistic details, pH dependence and intermediate structure of both electrochemical oxidation and reduction of acid orange 7. Surprisingly, the results indicate that a same redox couple (1-iminonaphthalen-2(1H)-one/1-aminonaphthalen-2-ol) is formed from both oxidation and reduction of acid orange 7. Also, an additional purpose of this work is electrochemical synthesis of three new derivatives of 1-amino-4-(phenylsulfonyl)naphthalen-2-ol (3a–3c) under constant current electrolysis via electrochemical oxidation (and reduction) of acid orange 7 in the presence of arylsulfinic acids as nucleophiles. The results indicate that the electrogenerated 1-iminonaphthalen-2(1 H)-one participates in Michael addition reaction with arylsulfinic acids to form the 1-amino-3-(phenylsulfonyl) naphthalen-2-ol derivatives. The synthesis was carried out in an undivided cell equipped with carbon rods as an anode and cathode. 2-Naphthol orange (acid orange 7), C16H11N2NaO4S, is a mono-azo water-soluble dye that extensively used for dyeing paper, leather and textiles1,2. The structure of acid orange 7 involves a hydroxyl group in the ortho-position to the azo group. This resulted an azo-hydrazone tautomerism, and the formation of two tautomers, which each show an acid− base equilibrium3–12.
Chapter 3: Experimental

Chapter 3: Experimental CHAPTER 3: EXPERIMENTAL 3.1 Basic concepts of the experimental techniques In this part of the chapter, a short overview of some phrases and theoretical aspects of the experimental techniques used in this work are given. Cyclic voltammetry (CV) is the most common technique to obtain preliminary information about an electrochemical process. It is sensitive to the mechanism of deposition and therefore provides informations on structural transitions, as well as interactions between the surface and the adlayer. Chronoamperometry is very powerful method for the quantitative analysis of a nucleation process. The scanning tunneling microscopy (STM) is based on the exponential dependence of the tunneling current, flowing from one electrode onto another one, depending on the distance between electrodes. Combination of the STM with an electrochemical cell allows in-situ study of metal electrochemical phase formation. XPS is also a very powerfull technique to investigate the chemical states of adsorbates. Theoretical background of these techniques will be given in the following pages. At an electrode surface, two fundamental electrochemical processes can be distinguished: 3.1.1 Capacitive process Capacitive processes are caused by the (dis-)charge of the electrode surface as a result of a potential variation, or by an adsorption process. Capacitive current, also called "non-faradaic" or "double-layer" current, does not involve any chemical reactions (charge transfer), it only causes accumulation (or removal) of electrical charges on the electrode and in the electrolyte solution near the electrode. There is always some capacitive current flowing when the potential of an electrode is changing. In contrast to faradaic current, capacitive current can also flow at constant 28 Chapter 3: Experimental potential if the capacitance of the electrode is changing for some reason, e.g., change of electrode area, adsorption or temperature.
Hydrodynamic Voltammetry As a Rapid and Simple Method for Evaluating Soil Enzyme Activities

Sensors 2015, 15, 5331-5343; doi:10.3390/s150305331 OPEN ACCESS sensors ISSN 1424-8220 www.mdpi.com/journal/sensors Article Hydrodynamic Voltammetry as a Rapid and Simple Method for Evaluating Soil Enzyme Activities Kazuto Sazawa 1,* and Hideki Kuramitz 2 1 Center for Far Eastern Studies, University of Toyama, Gofuku 3190, 930-8555 Toyama, Japan 2 Department of Environmental Biology and Chemistry, Graduate School of Science and Engineering for Research, University of Toyama, Gofuku 3190, 930-8555 Toyama, Japan; E-Mail: [email protected] * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel./Fax: +81-76-445-66-69. Academic Editor: Ki-Hyun Kim Received: 26 December 2014 / Accepted: 28 February 2015 / Published: 4 March 2015 Abstract: Soil enzymes play essential roles in catalyzing reactions necessary for nutrient cycling in the biosphere. They are also sensitive indicators of ecosystem stress, therefore their evaluation is very important in assessing soil health and quality. The standard soil enzyme assay method based on spectroscopic detection is a complicated operation that requires the removal of soil particles. The purpose of this study was to develop a new soil enzyme assay based on hydrodynamic electrochemical detection using a rotating disk electrode in a microliter droplet. The activities of enzymes were determined by measuring the electrochemical oxidation of p-aminophenol (PAP), following the enzymatic conversion of substrate-conjugated PAP. The calibration curves of β-galactosidase (β-gal), β-glucosidase (β-glu) and acid phosphatase (AcP) showed good linear correlation after being spiked in soils using chronoamperometry.
Stationary Electrode Voltammetry and Chronoamperometry in an Alkali Metal Carbonate-Borate Melt

AN ABSTRACT OF THE THESIS OF DARRELL GEORGE PETCOFF for the Doctor of Philosophy (Name of student) (Degree) in Analytical Chemistry presented onC (O,/97 (Major) (Date) Title: STATIONARY ELECTRODE VOLTAMMETRY AND CHRONOAMPEROMETRY IN AN ALKALI METAL CARBONATE - BORATE. MFT T Abstract approved: Redacted for Privacy- Drir. reund The electrochemistry of the lithium-potassium-sodium carbonate-borate melt was explored by voltammetry and chrono- amperometry. In support of this, a controlled-potential polarograph and associated hardware was constructed.Several different types of reference electrodes were tried before choosing a porcelain mem- brane electrode containing a silver wire immersed in a silver sulfate melt.The special porcelain compounded was used also to construct a planar gold disk electrode.The theory of stationary electrode polarography was summarized and denormalized to provide an over- all view. A new approach to the theory of the cyclic background current was also advanced. A computer program was written to facilitate data processing.In addition to providing peak potentials, currents, and n-values, the program also resolves overlapping peaks and furnishes plots of both processed and unprocessed data. Rapid-scan voltammetry was employed to explore the electro- chemical behavior of Zn, Co, Fe, Tl, Sb, As, Ni, Sn, Cd, Te, Bi, Cr, Pb, Cu, and U in the carbonate-borate melt. Most substances gave reasonably well-defined peaks with characteristic peak potentials and n-values.Metal deposition was commonly accompanied by adsorp- tion prepeaks indicative of strong adsorption, and there was also evi- dence of a preceding chemical reaction for several elements, sug- gesting decomplexation before reduction.
Cyclic Voltammetry

Cyclic Voltammetry Denis Andrienko January 22, 2008 2 Literature: 1. Allen J. Bard, Larry R. Faulkner “Electrochemical Methods: Fundamentals and Applications” 2. http://www.cheng.cam.ac.uk/research/groups/electrochem/teaching.html Chapter 1 Cyclic Voltammetry 1.1 Background Cyclic voltammetry is the most widely used technique for acquiring qualitative information about elec- trochemical reactions. it offers a rapid location of redox potentials of the electroactive species. A few concepts has to be introduced before talking about this method. 1.1.1 Electronegativity Electronegativity is the affinity for electrons. The atoms of the various elements differ in their affinity for electrons. The term was first proposed by Linus Pauling in 1932 as a development of valence bond theory. The table for all elements can be looked up on Wikipedia: http://en.wikipedia.org/wiki/Electronegativity. Some facts to remember: • Fluorine (F) is the most electronegative element. χF = 3.98. • The electronegativity of oxygen (O) χO = 3.44 is exploited by life, via shuttling of electrons between carbon (C, χF = 2.55) and oxygen (O): Moving electrons against the gradient (O to C) - as occurs in photosynthesis - requires energy (and stores it). Moving electrons down the gradient (C to O) - as occurs in cellular respiration - releases energy. • The relative electronegativity of two interacting atoms plays a major part in determining what kind of chemical bond forms between them. Examples: • Sodium (χNa = 0.93) and Chlorine (χCl = 3.16) = Ionic Bond: There is a large difference in electronegativity, so the chlorine atom takes an electron from the sodium atom converting the atoms into ions (Na+) and (Cl−).
Supporting Information Redox-Active and Semi-Conducting Donor

Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A. This journal is © The Royal Society of Chemistry 2018 Supporting Information Redox-active and Semi-conducting Donor-Acceptor Conjugated Microporous Polymers as Metal-free ORR Catalysts Syamantak Roy,a Arkamita Bandyopadhyay,b Mrinmay Das,c Partha Pratim Ray,c Swapan K. Patib and Tapas Kumar Maji*a a Molecular Materials Laboratory, Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India b New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore- 560064 c Department of Physics, Jadavpur University, Kolkata -700032 Table of Contents Physical Measurements ..................................................................................................................2 Computational Details ....................................................................................................................3 Electrochemical Measurements ......................................................................................................3 Experimental Section......................................................................................................................5 IR Spectra .......................................................................................................................................7 PXRD .............................................................................................................................................7
For Peer Review Only

IUPAC Terminology of electrochemical methods of analysis Journal: Pure and Applied Chemistry ManuscriptFor ID PeerPAC-REC-18-01-09.R2 Review Only Manuscript Type: Recommendation Date Submitted by the 27-Feb-2019 Author: Complete List of Authors: Pingarron, José; Complutense University of Madrid, Department of Analytical Chemistry Labuda, Jan; Slovak University of Technology, Department of Analytical Chemistry Barek, Jiří ; Charles University, Faculty of Science, Department of Analytical Chemistry Brett, Christopher; Universidade de Coimbra, Departamento de Química Camões, Maria; Universidade de Lisboa, Centro de Química Estrutural Fojta, Miroslav; Akademie ved Ceské Republiky, Institute of Biophysics Hibbert, David; University of New South Wales, School of Chemistry electoanalytical chemistry, electrodes, potentiometry, amperometry, Keywords: voltammetry, coulometry, electrogravimetry, conductometry, impedimetry, spectroelectrochemistry Author-Supplied Keywords: P.O. 13757, Research Triangle Park, NC (919) 485-8700 Page 1 of 62 IUPAC 1 2 3 4 IUPAC Provisional Recommendation 5 6 7 José M. Pingarrón1, Ján Labuda2, Jiří Barek3, Christopher M.A. Brett4, Maria Filomena 8 Camões5, Miroslav Fojta6, D. Brynn Hibbert7*. 9 10 11 Terminology of electrochemical methods of analysis (IUPAC 12 Recommendations 201x) 13 14 15 16 Abstract: Recommendations are given concerning the terminology of methods used in 17 electroanalytical chemistry.For PeerFundamental Review terms in electrochemistry Only are reproduced from 18 previous PAC Recommendations, and
A Brief Study of Cyclic Voltammetry and Electrochemical Analysis

International Journal of ChemTech Research CODEN (USA): IJCRGG, ISSN: 0974-4290, ISSN(Online):2455-9555 Vol.11 No.09, pp 77-88, 2018 A Brief Study of Cyclic Voltammetry and Electrochemical Analysis *1Joshi P.S., 2Sutrave D.S. 1Walchand Institute of Technology, Solapur University, Solapur, Maharashtra, India 2D.B.F Dayanand College of Arts and Science, Solapur University, Solapur, Maharashtra-413006, India Abstract : Electrochemistry is defined as the branch of chemistry that examines the phenomena resulting from combined chemical and electrical effects. This paper covers some of the common voltammetry techniques which are currently in use. Cyclic voltammetry is a widely used technique in electrochemistry .The cyclic voltammetry is a powerful tool to study the electrochemical behavior of a system by systematic study of current-voltage measurements of a given electrochemical cell. Brief study of cyclic voltammetry and the analysis of an electrochemical cell from cyclic voltammogramis described. I. Introduction Owing to the good stability, high power density and moderate energy compared to the conventional capacitors and batteries, electrochemical capacitors (supercapacitors, also called ultracapacitors) are the attractive power sources. The application of electrochemical capacitors lies in the field where high power density is required with small or short currents such as during start-up of electric vehicles or in power back-up systems (UPS)1.Energy storage in supercapacitor is due to the pure electrostatic interaction between the charged capacitor plates and the ions from the electrolyte solution and the processes associated with the redox reactions of electrode material. Usually, in the electrical double layer capacitors the materials used as electrodes are activated carbons, metal oxides or conductive polymers.
A Micro Computer Controlled High Speed High Resolution Cyclic

A micro computer controlled high speed high resolution cyclic voltammeter by Russell Allen Bonsteel A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Chemistry Montana State University © Copyright by Russell Allen Bonsteel (1986) Abstract: In cyclic voltammetry, the technique of applying known voltages to an electrochemical cell and recordings the response waveform on an x-y recorder is a area of significant growth. In its infancy, the voltages applied to the cell were delivered by manual control through a network of vacuum tubes, resistors, and capacitors. The waveform response curves were both crude in accuracy and precision. The next generation of electronics brought about the operational amplifier. While this increased the accuracy of the waveforms, reproducibility was still lagging because of the manual timing application of the input voltages, especially for multiple run sequences. It is proposed that by using state of the art integrated circuits and computer control that the manual application of the voltages can be eliminated and thereby increase both the precision and the reproducibility of the voltammetric waveform. With the implementation of the integrated circuits and computer control new schematic designs had to be employed. Solid state analog switches were used to route precise currents or voltages to carefully matched operational amplifiers. Timing routines were generated to maximize the amount of data to be collected and stored in computer memory. A sophisticated language called FORTH was ascertained to be the best vehicle to communicate between the computer and the cyclic voltammetric interface. The results were excellent on the implementation of the voltages to the electrodes in the chemical cell.
Voltammetric Techniques

Chapter 37 Voltammetric Techniques Samuel P. Kounaves Tufts University Department of Chemistry Summary General Uses • Quantitative determination of organic and inorganic compounds in aqueous and nonaqueous solutions • Measurement of kinetic rates and constants • Determination adsorption processes on surfaces • Determination electron transfer and reaction mechanisms • Determination of thermodynamic properties of solvated species • Fundamental studies of oxidation and reduction processes in various media • Determination of complexation and coordination values Common Applications • Quantitative determination of pharmaceutical compounds • Determination of metal ion concentrations in water to sub–parts-per-billion levels • Determination of redox potentials • Detection of eluted analytes in high-performance liquid chromatography (HPLC) and flow in- jection analysis 709 710 Handbook of Instrumental Techniques for Analytical Chemistry • Determination of number of electrons in redox reactions • Kinetic studies of reactions Samples State Species of interest must be dissolved in an appropriate liquid solvent and capable of being reduced or oxidized within the potential range of the technique and electrode material. Amount The amounts needed to obtain appropriate concentrations vary greatly with the technique. For example, cyclic voltammetry generally requires analyte concentrations of 10–3 to 10–5 M, whereas anodic strip- ping voltammetry of metal ions gives good results with concentrations as low as 10–12 M. Volumes may also vary from about 20 mL to less than a microliter (with special microelectrode cells). Preparation The degree of preparation required depends on both the sample and the technique. For determination of Pb(II) and Cd(II) in seawater with a microelectrode and square-wave anodic stripping voltammetry (ASV), no preparation is required. In contrast, determination of epinepherine in blood plasma at a glassy carbon electrode with differential pulse voltammetry (DPV) requires that the sample first be pre- treated with several reagents, buffered, and separated.
Part MF-9006 INSTRUCTION MANUAL Rotating Disk Electrode

RDE-2 June 2000 Part MF-9006 INSTRUCTION MANUAL Rotating Disk Electrode Bioanalytical Systems, Inc. 2701 Kent Avenue West Lafayette Indiana 47906 Copyright 2000 Bioanalytical Systems, Inc. This instrument, either wholly or in part, is manufactured for research purposes only. Use for medical diagnosis is not intended, implied, or recommended by the manufacturer. Use for this purpose and accountability for same rest entirely with the user. Table of Contents Table of Contents Section 1. Introduction . ............................................ 1 Features . ..................................................... 1 Specifications and Technical Data ..................................... 2 Accessories ..................................................... 2 Section 2. General Information ......................................... 3 User Updates ................................................... 3 Technical Changes ............................................... 3 Shipping Damage . ............................................... 3 Limited Warranty . .............................................. 3 Service....................................................... 4 Section 3. Installation . ............................................. 5 Inspection of Shipment . ......................................... 5 Parts of RDE-2. ................................................. 5 Location of RDE-2 ............................................... 5 Power Requirements ............................................. 6 Back Panel Controls and Connections ................................