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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 new and updated material is added for terms in 19 electroanalytical chemistry, classification of electrode systems, and eletroanalytical 20 21 techniques. 22 23 24 Keywords: electrodes, electroanalytical techniques, potentiometry, amperometry, 25 voltammetry, coulometry, electrogravimetry, conductometry, impedimetry, 26 spectroelectrochemistry 27 28 29 30 CONTENTS 31 1 PREFACE ..........................................................................................................................3 32 33 2 INTRODUCTION..............................................................................................................3 34 3 FUNDAMENTAL ELECTROCHEMICAL TERMS .......................................................4 35 36 4 GENERAL TERMS IN ELECTROANALYTICAL CHEMISTRY...............................14 37 5 ELECTRODE SYSTEMS ...............................................................................................20 38 39 6 ELECTROANALYTICAL TECHNIQUES....................................................................38 40 7 INDEX OF TERMS.........................................................................................................61 41 42 43 44 45 1 Complutense University of Madrid, Faculty of Chemistry, Department of Analytical Chemistry, 28040- 46 Madrid, Spain 47 2 Slovak University of Technology in Bratislava, Faculty of Chemical and Food technology, Institute of 48 Analytical Chemistry, SK-81237 Bratislava, Slovakia 49 3 Charles University, Faculty of Science, Department of Analytical Chemistry, CZ-128 43 Prague 2, Czech 50 Republic 51 4 University of Coimbra, Faculty of Sciences and Technology, Department of Chemistry, 3004-535 Coimbra, 52 Portugal 53 5 University of Lisbon, Faculty of Science, Centre for Structural Chemistry, 1749-016 Lisbon, Portugal 54 6 Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., CZ-612 65 Brno, Czech Republic 55 7 UNSW Sydney, School of Chemistry, Sydney, NSW 2052, Australia 56 * Corresponding Author: [email protected] 57 Note: This work was started under the project 2010-052-1-500: Electroanalytical Chemistry – Revision of the 58 Orange Book Chapter 7, with membership of José M. Pingarrón, Ján Labuda, Maria Filomena Camões, 59 Christopher M.A. Brett, and D. Brynn Hibbert. 60 1 P.O. 13757, Research Triangle Park, NC (919) 485-8700 IUPAC Page 2 of 62 1 2 3 4 8 INDEX OF ABBREVIATIONS......................................................................................61 5 9 MEMBERSHIP OF SPONSORING BODIES ................................................................61 6 7 10 REFERENCES.................................................................................................................61 8 9 10 11 1 PREFACE 12 13 The recommendations contained in this document complete the terminology of 14 electroanalytical methods. The terms represent a revised version of those included in previous 15 IUPAC recommendations [1-3] and the corresponding chapter of the IUPAC Orange Book, 16 the third edition of the Compendium of Analytical Nomenclature [4] . 17 For Peer Review Only 18 These Recommendations will become a chapter in the revised Orange Book (now titled the 19 th 20 Compendium of Terminology in Analytical Chemistry, 4 edition) [5]. 21 22 23 2 INTRODUCTION 24 25 The analytical methods classified in this chapter include those in which electrochemical 26 processes or phenomena are the core of the measurement principle [VIM 2.4] involving 27 28 electrochemical cells providing qualitative and quantitative responses. These responses can 29 be calibrated in terms of concentrations. Typical examples are given in Table 2.1. 30 31 32 Table 2.1: Kinds of methods of electroanalytical chemistry based on quantities controlled and 33 34 measured. I is the symbol for electric current, E is the symbol for electrode potential and Q is 35 the symbol for electric charge [6]. 36 37 Method Quantity measured Quantity controlled 38 potentiometry E I = 0 39 40 amperometry I E 41 voltammetry I = f(t) E = f(t) 42 푡2 43 direct coulometry 푄 = ∫ 퐼(푡)d푡 E = constant 44 푡1 45 46 conductometry conductivity (휅 ) 47 impedimetry electrical impedance (Z) E = constant + f(t) 48 49 50 Combined methods, such as spectroelectrochemical techniques and electroanalytical methods 51 52 coupled to separation methods, may be defined here or in the relevant chapters of the fourth 53 edition of the Orange Book [5] or in IUPAC Recommendations (e.g. [7]). 54 55 Terms defined in the International Vocabulary of Metrology – Basic and general concepts 56 and associated terms (VIM) [8] are given in italics on first use in a section and are referred to 57 58 as [VIM x.y]. Other terms in italics refer to terms defined within this paper. Basic 59 60 2 P.O. 13757, Research Triangle Park, NC (919) 485-8700 Page 3 of 62 IUPAC 1 2 3 rd 4 electrochemical terms are taken from the Green Book, 3 edition [6] with changes made only 5 to formatting. When referencing sources of terms, “Source [ref] p xyz” is used in the sense 6 7 that information is taken from it. 8 9 10 3 FUNDAMENTAL ELECTROCHEMICAL TERMS 11 12 Terms in this section are reproduced from IUPAC Recommendations [1], where the number 13 that follows, if present, is the entry number of the term, and from the Green Book [6] with 14 15 either no changes or only minor changes to formatting. 16 17 18 3.1 anode For Peer Review Only 19 Electrode of an electrochemical cell through which net electric current flows and at 20 which the predominating electrochemical reaction is an oxidation. 21 22 Note 1: At an anode, electrons are produced in a galvanic cell or extracted in an 23 electrolytic cell. 24 25 Note 2: The concepts of “anode” and “cathode” are related only to the direction of 26 electron flow, not to the polarity of the electrodes. 27 28 Source: [6] p 75. 29 30 31 3.2 apparent number of electrons transferred, zapp 32 See electron number of an electrochemical reaction 33 34 35 3.3 applied potential, Eapp 36 deprecated: voltage 37 38 Difference of electric potentials measured between identical metallic leads to two 39 electrodes of an electrochemical cell. 40 41 Note 1: The applied potential is divided into a) two electrode potentials, each of 42 which is the difference of potential existing between the bulk of the solution 43 and the interior of the conducting material of the electrode, b) an IR or 44 ohmic potential drop through the solution of resistance R at electric current I, 45 46 and c) another ohmic potential drop through each electrode and its metallic 47 leads. The definition of Galvani and Volta potential differences can be found 48 on p. 70 and p. 71 in [6]. 49 Note 2: Single electrode potentials relative to hypothetical standards, such as 50 51 vacuum zero, are not experimentally accessible. 52 Source: [1]. 53 54 55 3.4 cathode 56 57 Electrode of an electrochemical cell through which net electric current flows and at 58 which the predominating electrochemical reaction is a reduction. 59 60 3 P.O. 13757, Research Triangle Park, NC (919) 485-8700 IUPAC Page 4 of 62 1 2 3 Note : The concepts of “anode” and “cathode” are related only to the direction of 4 electron flow, not to the polarity of the electrodes. 5 6 Source: [6] p 75. 7 8 9 3.5 electric charge, Q 10 quantity of electricity 11 12 Integral of electric current over time. 13 14 Q I dt 15 16 Note 1: In electrolysis, the electrooxidation of an electroactive substance results in 17 positiveFor values Peer of Q; the Review electroreduction Onlyof an electroactive substance gives 18 rise to negative values of Q. 19 20 Note 2: The components of an overall value of Q should be named and given 21 symbols similar to those of the corresponding electric current, e.g., QDL: 22 double-layer charge, Qt : instantaneous charge, etc. 23 24 Source: [6] p 4. 25 26 27 3.6 electric current 28 current 29 30 Phenomenon associated with the movement of charged particles (for example electrons, 31 ions). 32 33 34 3.7 electric current (quantity), I 35 current 36 37
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