DOCSLIB.ORG

Effects of Organic Compounds on Anodic Stripping Voltammetry of Metals Using a Mercury-Film Micro-Platinum Electrode

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Effects of Organic Compounds on Anodic Stripping Voltammetry of Metals Using a Mercury-Film Micro-Platinum Electrode EFFECTS OF ORGANIC COMPOUNDS ON ANODIC STRIPPING VOLTAMMETRY OF METALS USING A MERCURY-FILM MICRO-PLATINUM ELECTRODE by MARANAEK SIAGIAN A Thesis presented for the degree of Master of Science at THE UNIVERSITY OF NEW SOUTH WALES Supervisors : 1. A/Prof. P.W. Alexander. 2. Prof. D.B. Hibbert. April, 1991 UNIVERSITY OF N.S.VV. 2 7 AUG 1993 LIBRARIES I hereby declare that this thesis is my own work and that, to the best of my knowledge and belief, it contains no material previously published or written by another person nor material which to a substantial extent has been accepted for the award of any other degree or diploma of a University or other Institute of higher learning, except where due acknowledgement is made in the text. 2-^ - o/\ - | 1 ACKNOWLEDGEMENTS. In the name of Allah, most Gracious and most Merciful I wish to express my sincere thanks to my supervisors, Associate Professor P.W. Alexander and Professor D.B. Hibbert, for their valued advice, guidance, suggestions, encouragement and help throughout this work. Thanks to all members of the Department of Analytical Chemistry and School of Chemistry. I realize that all of you contributed help for this work. And also to my colleagues, who have encouraged me, shared experiences and helped me during this work, I extend my appreciation. My appreciation goes to the Australian International Development Assistance Bureau (AIDAB) for financial support and guidance given and to the PPPTMGB "LEMIGAS" Jakarta, Indonesia, for the nomination and my leave of absence. Finally, I wish to thank to my wife Nur and sons, Enru and Azri for their patience and understanding. May "Allah " guide us to the straight way, amen. ABSTRACT This study evaluates the uses of a mercury-film micro-platinum electrode as a working electrode for anodic stripping voltammetry (ASV) of trace metals. The study of the response of this electrode which is of 5 mm length and 100 pm in diameter includes the effects of hydrocarbons, phenolics, pyridines, sulphur compounds, crude oils and surfactants on the ASV scans. The micro-platinum electrode plated with a thin mercury film by in situ deposition of mercury (5 x 10'5 M) in 0.1 M acetate buffer solution at pH 4.5 was chosen as the working electrode in preference to the hanging mercury drop electrode and the thin-film glassy carbon electrodes because of its stationary configuration, simple preparation and low cost. ASV scans of cadmium, lead, copper and mercury solutions are shown to give excellent resolution of the stripping peaks recorded at -0.80, -0.65, -0.20 V and +0.09 V (vs SCE), respectively. Zinc was detectable using the Pt-electrode only at high concentration in the ppm range. The main objective of this study was the possibility of indicating the presence of various classes of organic compounds by their effects on the ASV scans of the above metal ion solutions. Addition of these organic compounds to standard mixtures of cadmium, lead, copper and mercury was studied. Hydrocarbon compounds showed no significant effect on the ASV scans, but non-hydrocarbon compounds had a variety of effects on the peaks observed. There was a very marked effect of crude oils on the ASV of the metal ion mixture when samples of 0.1 g of crude oil was dispersed in 100 ml of the aqueous solution containing 100 ppb of each the metal ions. It is shown, that the non­ hydrocarbon components in the crude oils are the main cause of the adsorption effects. The non-hydrocarbon compounds studied had various effects on the ASV scans. For example, in the presence of a neutral surfactant (Triton X-100 at a concentration of 2.0 ppm) the Cd and Pb peaks disappeared but the other peaks were less severely affected. Similarly for the other organic compounds studied, different effects on the ASV peaks were observed, suggesting that this scanning method may be of value for indicating the presence of certain classes of organic compounds. Thus the possibility of the ASV scan as a rapid indicating method may be considered for detecting compounds such as crude oils, surfactants, detergents and dispersants which may be present in the environment. TABLE OF CONTENTS CHAPTER 1. INTRODUCTION AND LITERATURE REVIEW 1 1.1. GENERAL INTRODUCTION 1.2. ELECTROCHEMICAL METHODS 2 1.2.1. Conductometric Analysis 2 1.2.2. Potentiometrie Analysis 3 1.2.3. Coulometric Analysis 4 1.2.4. Electrogravimetric Analysis 5 1.3. ANODIC STRIPPING VOLTAMMETRY (ASV) 5 1.3.1. Principle of AS V 6 1.3.2. Stripping Techniques in ASV 12 1.3.2.1. Linear Sweep and Staircase Voltammetry 12 1.3.2.2. Pulse Voltammetry 14 1.3.3. Comparison of ASV and CSV 16 1.3.4. Instrumentation 17 1.3.5. Electrodes 21 1.3.6. Reference and Auxiliary Electrodes 20 1.3.7. Working Electrodes 20 1.3.7.1. Mercury Electrodes 20 1.3.7.2. Solid Electrodes 24 1.3.8. Supporting Electrolyte 24 1.4. APPLICATION OF ASV ON METAL ANALYSIS 26 1.4.1. ASV Determination of Cadmium 28 1.4.2. ASV Determination of Lead 29 1.4.3. ASV Determination of Copper 30 1.5. ORGANIC INTERFERENCES ON ASV 30 1.5.1. Effect of Organic Compounds on AS V 32 1.5.2. Effect of Surface-active Substances on ASV 33 1.5.3. Effect of Metal complex-forming compounds on ASV 34 1.6. AIMS OF THE THESIS 35 1.7. REFERENCES 37 CHAPTER 2. EXPERIMENTAL 4 4 2.1. INSTRUMENTATION 44 2.1.1. Polarographic Analyzer 44 2.1.2. Electrodes 46 2.2. REAGENTS 46 2.2.1. Water 46 2.2.2. Metal Standard Solutions 46 2.2.3. Mercury Solutions 47 2.2.4. Sodium Acetate and Acetic Acid Solutions 47 2.3. PROCEDURES 47 2.3.1. Preparation of a micro-platinum electrode 47 2.3.2. ASV Scanning of Cd, Pb and Cu using a micro-platinum electrode 49 2.3.3. ASV Scanning of Zn, Cd, Pb and Cu 49 2.3.4. ASV Scanning of Cd, Pb and Cu using metal electrodes 49 2.3.5. ASV Scanning of Cd, Pb and Cu at Various Deposition Potentials 50 2.3.6. ASV Scanning of Cd, Pb and Cu at Various pH 50 2.3.7. ASV of Cd, Pb and Cu in Various Cone ofHg(II) 50 2.3.8. ASV of Cd, Pb and Cu in Aqueous Solutions with dissolved 51 Organic Compounds 2.3.9. ASV of Cd, Pb and Cu in Aqueous Solutions with Dissolved 51 Crude Petroleum [5,6] 2.3.10. Peak measurements 51 2.4. ASSESSMENT OF PRECISION 52 2.5. REFERENCES 53 CHAPTER 3. RESULTS AND DISCUSSION. 5 4 3.1. ASV OF Cd, Pb AND Cu USING A MERCURY-FILM MICRO-PLATINUM ELECTRODE 55 3.1.1. Effect of Deposition Potential 59 3.1.2. Effect of pH 60 3.1.3. Effect of Concentration of Mercury 60 3.1.4. Repeatability of ASV of Cd, Pb and Cu 62 3.1.5. Calibration Curve of Cd, Pb and Cu 63 3.2. EFFECT OF ORGANIC COMPOUNDS 66 3.2.1. Effect of hydrocarbon compounds 66 3.2.2. Effect of non-hydrocarbon compounds 68 3.2.3. Effects of organic sulphur compounds 71 3.3. EFFECT OF CRUDE PETROLEUM OILS 75 3.4. EFFECT OF SURFACTANTS 78 3.5. REFERENCES 83 CHAPTER 4. CONCLUSION 85 vii CHAPTER ONE INTRODUCTION AND LITERATURE REVIEW 1.1 GENERAL INTRODUCTION Since the effect of heavy metals on biological processes tends to be toxic, many reports have been published on methods to determine very low levels of the heavy metals in an aquatic environment. However there exists a need for a direct and rapid method of determining trace metals in the marine environment. Anodic Stripping Voltammetry (ASV) has been shown to possess high sensitivity and excellent resolution for certain metals in sea water [1], but its application is sometimes difficult or even impossible because of interference effects. The most frequent problems are an overlap of the analyte peaks or the presence of organic compounds, such as humic acid [2], fulvic acid, gelatine, alkyl phosphate, surfactants and polysaccharides [3], as interferences. While ASV is a useful technique'for determination of heavy metals , its limitations and possible interferences appear to be inadequately appreciated. The effects of adsorption on ASV results, have been considered by some workers. Although adsorption of organic substances onto mercury electrodes is well-known from polarographic studies [4], Brezonik et al. found effects of adsorption of a variety of model organic compounds, representative of types of organic substances occurring in natural waters, on hanging mercury drop electrodes in the anodic stripping voltammetric analysis of trace metals [3]. In this present study, the effect of organic compounds on anodic stripping voltammetry of trace metals using a mercury-film micro-platinum (0 = 100 pm) electrode is described. 2 It is proposed in this introductory chapter to briefly discuss electroanalytical methods with special emphasis on anodic stripping and the effect of organic compounds on metal analysis by anodic stripping voltammetry. 1.2 ELECTROANALYTICAL METHODS Electrochemistry in an electrolyte always requires two electrodes and can be carried out by means of either non-faradaic or faradaic methods. Non-faradaic methods of electroanalysis, with a zero net electrical current, are represented by conductometric and normal potentiometric analysis. Faradaic methods of electroanalysis, with a-non zero net electrical current, are represented by voltammetric, electrogravimetric and coulometric analysis [5]. 1.2.1' Conductometric Analysis This method is primarily based on measurement of the electrical conductance df a solution from which, by previous calibration, the analyte concentration can be derived.
Load more

Recommended publications
  • Square-Wave Protein-Film Voltammetry: New Insights in the Enzymatic Electrode Processes Coupled with Chemical Reactions
    Journal of Solid State Electrochemistry https://doi.org/10.1007/s10008-019-04320-7 ORIGINAL PAPER Square-wave protein-film voltammetry: new insights in the enzymatic electrode processes coupled with chemical reactions Rubin Gulaboski1 & Valentin Mirceski2,3 & Milivoj Lovric4 Received: 4 April 2019 /Revised: 9 June 2019 /Accepted: 9 June 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract Redox mechanisms in which the redox transformation is coupled to other chemical reactions are of significant interest since they are regarded as relevant models for many physiological systems. Protein-film voltammetry, based on surface confined electro- chemical processes, is a methodology of exceptional importance, which is designed to provide information on enzyme redox chemistry. In this work, we address some theoretical aspects of surface confined electrode mechanisms under conditions of square-wave voltammetry (SWV). Attention is paid to a collection of specific voltammetric features of a surface electrode reaction coupled with a follow-up (ECrev), preceding (CrevE) and regenerative (EC’) chemical reaction. While presenting a collection of numerically calculated square-wave voltammograms, several intriguing and simple features enabling kinetic char- acterization of studied mechanisms in time-independent experiments (i.e., voltammetric experiments at a constant scan rate) are addressed. The aim of the work is to help in designing a suitable experimental set-up for studying surface electrode processes, as well as to provide a means for determination of kinetic and/or thermodynamic parameters of both electrode and chemical steps. Keywords Kinetics of electrode reactions and chemical reactions . Surface EC′ catalytic mechanism . Surface ECrev mechanism . Surface CrevE mechanism . Square-wave voltammetry Introduction modulation applied, however, SWV is seldom explored as a technique for mechanistic evaluations.
    [Show full text]
  • Fundamentals of Electrochemistry
    Yonsei University Fundamentals of Electrochemistry References Electrochemical Methods : Fundamentals and Applications, 2nd edition. by A. J. Bard and L.R. Faulkner • Makes use of electrochemistry for the purpose of analysis • A voltage (potentiometry) or current (voltammetry) signal originating from an electrochemical cell is related to the activity or concentration of a particular species in the cell. • Excellent detection limit (10-8 ~ 10-3 M): 1959, Nobel Prize (Polarography) • Inexpensive technique. • Easily miniaturized : implantable and/or portable (biosensor, biochip) Electrochemical cells Galvanic cell Digital High input impedance voltmeter A B e- Anode reaction Zn Zn2+ + 2e- : oxidation e- Cathode reaction Cu2+ + 2e- Cu (-)KCl (+) : reduction Zn Cu Salt bridge Zn + Cu2+ Zn2+ + Cu K+ - - 2e Cl 2e- Cell potential : a measure of difference in electron Zn2+ energy between the two electrodes 2- SO4 Zn Cu Open-circuit potential (zero-current potential) Zn2+ Cu2+ 2+ 2+ Zn 2- 2- Cu : can be calculated from thermodynamic data, ie. SO4 SO 4 standard cell potentials of the half-cell reactions. Anode Cathode Fig. 27.1 Electrochemical cell consisting of a zinc electrode in 0.1 M ZnSO4, a copper electrode in 0.1 M CuSO4, and a salt bridge. Galvanic cell. (From Heineman book) Standard Electrode Potential Table 22.1 Standard Electrode Potentials Reaction E0 at 25 ℃, V - - Cl2(g) + 2e 2Cl +1.359 + - O2(g) + 4H +4e 2H2O +1.229 - - Br2(aq) + 2e 2Br +1.087 - - Br2(l) + 2e 2Br +1.065 Ag+ + e- Ag(s) +-.799 Reduction 자발적 Fe3+ + e- Fe2+ +0.771 - - - I3 + 2e 3I +0.536 Cu2+ + 2e- Cu(s) +0.337 - - Hg2Cl2(s) + 2e 2Hg(l) + 2Cl +0.268 AgCl(s) + e- Ag(s) + Cl- +0.222 3- - 2- A quantitative description of the relative driving force Ag(S2O3)2 + e Ag(s) + 2S2O3 +0.010 for a half-cell reaction.
    [Show full text]
  • Computer-Aided Analytical Methods - a Review
    COMPUTER-AIDED ANALYTICAL METHODS - A REVIEW Läszlö Kekedy-Nagy Chair of Analytical Chemistry Faculty of Chemistry and Chemical Engineering Babe§-Bolyai University 3400 Cluj-Napoca, Romania INTRODUCTION Digital computers have become integral components of modern methods of analysis, influencing both instrument design and analytical methods. To understand the role of a computer in a specific instrumental method, it is necessary to consider the interaction among instrument, computer and analyst. Computers are being increasingly used in analytical work, but a survey of the literature shows that their potential has not yet been fully utilized. They offer enormous flexibility and sophistication in the execution and control of experiments, and their influence will doubtless be more and more widely felt. The following should be mentioned as main concerns: 1) Determination of the optimum analytical conditions, selecting the values of different parameters (e.g., the input signal) such that the best response is possible. In this respect, in order to avoid excessive experimental work and calculations and simplify operations, the mathematical modeling of the relations investi- gated is necessary. 2) Control of the measurement of analytical signals, used, e.g., to control the timing of different phases of the experiment, to prevent or warn against operator errors. 3) Data acquisition and storage of the analytical information. 4) Processing of analytical data is perhaps the main benefit that computers offer for analytical chemists. The computer makes it possible to qualify and classify the hidden information, using various chemometric methods including application of analytical intelligence, such as pattern recognition or expert control of chemical analysis systems.
    [Show full text]
  • Hydrodynamic Studies of the Electrochemical Oxidation of Organic Fuels
    Hydrodynamic Studies of the Electrochemical Oxidation of Organic Fuels by c Azam Sayadi A thesis submitted to the School of Graduate Studies in partial fulfilment of the requirements for the degree of Doctor of Philosophy Department of Chemistry Memorial University of Newfoundland September 2020 St. John's Newfoundland Abstract A clear understanding of small organic molecules (SOM) electrochemical oxidation opens a great opportunity for breakthrough in the development of fuel cell technology. SOM such as formic acid, methanol, and ethanol can produce electrical power through their oxidation in the fuel cell's anode. These molecules are also known as organic fuels and theoretically have the potential to produce close to 100% energy efficiency in a fuel cell. However, fast and complete oxidation of some organic fuels, such as ethanol, has not been achieved at this time, and has led to a dramatic decrease in the level of fuel cell efficiency. Therefore, a comprehensive study of the electrocatalytic oxidation mechanisms of organic fuels as well as a determination of the average number of transferred electrons (nav) are crucial for the enhancement of fuel cell efficiency. Hydrodynamic methods are highly effective approaches for these study purposes, and they have the ability to emulate the hydrodynamic conditions of a fuel cell anode. The main purpose of this project was establishing a simple and novel system for the assessment of various fuel cell catalysts performances in relation to formic acid, methanol and ethanol electrochemical oxidation. For this purpose, we applied two different approaches of hydrodynamic techniques, rotating disk voltammetry (RDV) and flow cell electrolysis.
    [Show full text]
  • Electroanalytical Methods: Guide to Experiments and Applications, 2Nd
    Electroanalytical Methods Fritz Scholz Editor Electroanalytical Methods Guide to Experiments and Applications Second, Revised and Extended Edition With contributions by A.M. Bond, R.G. Compton, D.A. Fiedler, G. Inzelt, H. Kahlert, Š. Komorsky-Lovric,´ H. Lohse, M. Lovric,´ F. Marken, A. Neudeck, U. Retter, F. Scholz, Z. Stojek 123 Editor Prof. Dr. Fritz Scholz University of Greifswald Inst. of Biochemistry Felix-Hausdorff-Str. 4 17487 Greifswald Germany [email protected] ISBN 978-3-642-02914-1 e-ISBN 978-3-642-02915-8 DOI 10.1007/978-3-642-02915-8 Springer Heidelberg Dordrecht London New York Library of Congress Control Number: 2009935962 © Springer-Verlag Berlin Heidelberg 2010 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer. Violations are liable to prosecution under the German Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Cover design: WMXDesign GmbH, Heidelberg Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Electroanalytical Methods Fritz Scholz dedicates this book to the memory of his late parents Anneliese and Herbert Scholz Preface to the Second Edition The authors are pleased to present here the second edition of the book “Electroanalytical Methods.
    [Show full text]
  • Présentation Powerpoint
    Application Note General Electrochemistry AP-GE05 Staircase Voltammetry This Application Note describes how the Staircase Voltammetry method works by giving an example with Ferri/Ferrate solution. Application Note Introduction The Staircase Voltammetry is a flexible method to investigate and record voltammograms of any electrochemical samples. You can set the potential points versus OCP or reference electrode, define the step potential, step duration, scan rate and then start the test. What makes this method special is that the user can define the number of segment. By defining the segment, the number of sweeping (scanning) potential between two vertexes is defined. When the number of segment is 1, then there will be a single-sweep voltammogram. When the number of segment is even means to have complete cycles. Parameters The Parameters of the staircase voltammetry are shown in figure 1. With the above default settings, the potential 1 is set to -1000 mV versus REF electrode, then scan rate is set at 10 mV/s up to achieve to potential 2 which is defined as 1000 mV. In the segment part, the user can define the number of sweeps. In figure 2, different results corresponding to different number of segments are shown. Figure 1: The parameters 2 Application Note (1) The number of segment is 1 (2) The number of segment is 2 Figure 2: Final result, Potential vs Current When the segment is defined as 1, only single-sweep voltammogram will be gained. When the segment is defined as 2 (or any even number) the result will be a cyclic voltammogram.
    [Show full text]
  • How to Cite Complete Issue More Information About This
    Revista Cubana de Química ISSN: 0258-5995 ISSN: 2224-5421 Universidad de Oriente Vilasó-Cadre, Javier Ernesto; Arada-Pérez, María de los Ángeles; Arce-Castro, Jorge; Baeza-Reyes, Dr.C. Study of the potential sweeps in the manual staircase voltammetry Revista Cubana de Química, vol. 32, no. 2, 2020, May-August, pp. 287-298 Universidad de Oriente Available in: http://www.redalyc.org/articulo.oa?id=443564573008 How to cite Complete issue Scientific Information System Redalyc More information about this article Network of Scientific Journals from Latin America and the Caribbean, Spain and Journal's webpage in redalyc.org Portugal Project academic non-profit, developed under the open access initiative Rev. Cubana Quím. Vol.32, no.2 mayo-agosto, 2020, págs. 287-298, e-ISSN: 2224-5421 Artículo original Study of the potential sweeps in the manual staircase voltammetry Estudio de los barridos de potencial en la voltamperometría manual de barrido en escalera MSc. Javier Ernesto Vilasó-Cadre1* https://orcid.org/0000-0001-5172-7136 Dra.C. María de los Ángeles Arada-Pérez2 https://orcid.org/0000-0001-9262-2066 Jorge Arce-Castro2 https://orcid.org/0000-0002-5443-6796 Dr.C. José Alejandro Baeza-Reyes3 https://orcid.org/0000-0001-9621-8175 1Institute of Metallurgy. Universidad Autónoma de San Luis Potosí, México. 2Faculty of Natural and Exact Sciences. Universidad de Oriente, Santiago de Cuba, Cuba. 3Faculty of Chemistry. Universidad Nacional Autónoma de México. *Autor para la correspondencia. correo electrónico: [email protected] ABSTRACT Voltammetry can be developed using manual potentiostats. This study focuses on the potential sweeps and its influence on the voltammograms in the manual staircase voltammetry.
    [Show full text]
  • EC-Lab Software: Techniques and Applications
    EC-Lab Software: Techniques and Applications Version 10.38 – August 2014 Equipment installation WARNING !: The instrument is safety ground to the Earth through the protective con- ductor of the AC power cable. Use only the power cord supplied with the instrument and designed for the good current rating (10 Amax) and be sure to connect it to a power source provided with protective earth contact. Any interruption of the protective earth (grounding) conductor outside the instrument could result in personal injury. Please consult the installation manual for details on the installation of the instrument. General description The equipment described in this manual has been designed in accordance with EN61010 and EN61326 and has been supplied in a safe condition. The equipment is intended for electrical measurements only. It shall not be used for any other purpose. Intended use of the equipment This equipment is an electrical laboratory equipment intended for professional and intended to be used in laboratories, commercial and light-industrial environments. Instrumentation and ac- cessories shall not be connected to humans. Instructions for use To avoid injury to an operator the safety precautions given below, and throughout the manual, must be strictly adhered to, whenever the equipment is operated. Only advanced user can use the instrument. Bio-Logic SAS accepts no responsibility for accidents or damage resulting from any failure to comply with these precautions. GROUNDING To minimize the hazard of electrical shock, it is essential that the equipment is connected to a protective ground through the AC supply cable. The continuity of the ground connection should be checked periodically.
    [Show full text]
  • The Development of Electrochemical Tools For
    NEW METHODS IN BIOGEOCHEMISTRY: THE DEVELOPMENT OF ELECTROCHEMICAL TOOLS FOR THE MEASUREMENT OF DISSOLVED AND SOLID STATE COMPOUNDS IN NATURAL SYSTEMS Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften am Fachbereich 5 der Universität Bremen Vorgelegt von Jochen Nuester Bremen 2005 Die vorliegende Arbeit wurde in der Zeit von Mai 2000 bis August 2005 am Max Planck Institut für Marine Mikrobiologie erstellt. 1. Gutachter: Prof. Dr. Bo Barker Jørgensen 2. Gutachter: Prof. Dr. Jörn Peckmann Prüfer: Prof. Dr. Achim Kopf Dr. Sabine Kasten Tag des Promotionskolloquium: 26. August 2006 II New Methods in Biogeochemistry III New Methods in Biogeochemistry IV New Methods in Biogeochemistry Acknowledgements Acknowledgements This PhD thesis deals with the development of new tools and methods to describe biogeochemical processes. Several aspects concerning the speciation have been studied; especially new methods were described for the determination of solid iron compounds, the detection of dissolved transition metals, and the complexation of such transition metals. The financial support for this thesis came from the Max Planck Society and the European Union is grateful acknowledged. First of all, I would like to thank Prof. Bo Barker Jørgensen for accepting me as his PhD student, and the opportunity to carry out this work at the Max Planck Institute. I am very grateful to my mentor and friend Dr. Ole Larsen for the initiation of the work, for the way he taught me to think interdisciplinary, for his supervision, and his support. He always had an open ear, and he usually had very inspiring answers to my questions. I like to thank Prof. Stan van den Berg at the University of Liverpool for the opportunity to stay at his laboratory and the fruitful cooperation.
    [Show full text]
  • CH Instruments Model 1100C Series User Manual
    Model 1100C Series Electrochemical Analyzer User Manual CH Instruments CH Instruments Model 1100C Series User Manual © 2014 CH Instruments, Inc. All rights reserved. No parts of this work may be reproduced in any form or by any means - graphic, electronic, or mechanical, including photocopying, recording, taping, or information storage and retrieval systems - without the written permission of the publisher. Products that are referred to in this document may be either trademarks and/or registered trademarks of the respective owners. The publisher and the author make no claim to these trademarks. While every precaution has been taken in the preparation of this document, the publisher and the author assume no responsibility for errors or omissions, or for damages resulting from the use of information contained in this document or from the use of programs and source code that may accompany it. In no event shall the publisher and the author be liable for any loss of profit or any other commercial damage caused or alleged to have been caused directly or indirectly by this document. Printed: August 2014 in Austin, Texas. Contents i Table of Contents Chapter 1 General Information 1 1.1 Introduction................................................................................................................................... 2 1.2 Electrochemical................................................................................................................................... Techniques 3 1.3 Software..................................................................................................................................
    [Show full text]
  • UCLA Electronic Theses and Dissertations
    UCLA UCLA Electronic Theses and Dissertations Title Development of potentiostat platform for complex voltammetric measurements and self- adjustable electrolysis Permalink https://escholarship.org/uc/item/8zx4m4c9 Author Chan, Yin Shing Gary Publication Date 2020 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA Los Angeles Development of potentiostat platform for complex voltammetric measurements and self-adjustable electrolysis A thesis submitted in partial satisfaction of the requirements for the degree Master of Science in Chemistry by Yin Shing Gary Chan 2020 ABSTRACT OF THE THESIS Development of potentiostat platform for complex voltammetric measurements and self-adjustable electrolysis by Yin Shing Gary Chan Master of Science in Chemistry University of California, Los Angeles, 2020 Professor Chong Liu, Chair With rapid technological progress, electrochemical methods are being developed and improved throughout the years. Outdated models of electrochemical equipment like potentiostats are replaced with newer models with more functions and capability. Since those outdated models are programmed using programming language like C++, users can utilize the source code to program new features to the outdated potentiostats, extending its period of use. We developed methods enabling users to create new functionality of an electrochemical analytical system (Emstat3 from PalmSens BV® ) using its software development platform on MATLAB® to perform complex voltammetric measurements and self-adjustable electrolysis. Complex voltammetric measurement is defined by running chronoamperometry under arbitrary potential waveform rather than the traditional constant voltage chronoamperometry or triangular potential waveform used in cyclic voltammetry. Self-adjustable electrolysis is demonstrated as a proof-of-concept via a nanowire array electrode, monitoring, and self-adjusting potentiostat parameters throughout the ii experiment with the execution of a control loop.
    [Show full text]
  • Measuring Surface-Related Currents Using Digital Staircase Voltmmetry
    Measuring Surface-related Currents using Digital Staircase Voltammetry 2,3,4,5 Introduction staircases instead of true ramps . In staircase voltammetry, current can be sampled at various points Cyclic Voltammetry (CV) is inarguably the most popular during the step. Two of the reports2,3 investigated and electrochemical technique. It owes its well-deserved tabulated the effects of this choice of sampling time. reputation to its ability to deduce reaction mechanisms Another report4 suggested the use of heavy analog with relatively low-cost equipment and quick filtering either on the applied or on the recorded signal experimentation. Since the often-cited paper by as a way of eliminating the difference. The author 1 Nicholson and Shain , the technique has been the demonstrated that through appropriately-chosen analog centerpiece of any electrochemical study. filters, a ramp can be approximated by a staircase and CV involves sweeping the potential linearly between two the measured response is not adversely affected. limits at a given sweep-rate while measuring current. A later study5 employed simulations to show that, The sweep-rate chosen can be varied from few provided the potential steps are small enough, a microvolts per second to millions of volts per second. staircase signal generated similar results to the linear Electrochemical instrumentation has evolved far since ramp. The author investigated different coupled the days of Nicholson and Shain. Currently, most chemical-reaction mechanisms including EC, CE, ECE, manufacturers (including Gamry) make digital etc., in addition to surface-bound reactions like instruments with digital signal generators. These signal amalgamation and adsorption. generators approximate the linear sweep with a staircase In this note, we investigate the differences between data of variable step sizes and durations.
    [Show full text]