Classification of electrochemical methods

It is the aim of this chapter to explain the basic requirements for performing electrochemistry, such as equipment, electrodes, electrochemical cells and boundary conditions to be respected. The following chapter focuses on the basic theory of charge transfer at the electrode-electrolyte solution interface and at transport phenomena of the analyte towards the electrode surface. In Chapter3, a theoretical overview of the electrochemical methods applied in the work described in this book is given. 

Essentially, the items mentioned above will be described as a function of the type of electrochemical method. The methods described and used in the work of this book can therefore be divided into three groups  

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Figure 2 Classification of electrochemical methods for the destruction of organics...

Three broad classifications of electrochemical methods are used in this chapter. Po-tentiometric methods include zero-current potentiometry and methods in which current of controlled magnitude is apphed to the working electrode, such as in potentiometric stripping analysis (PSA). Amperometric methods consider all techniques in which current is measured these include constant-potential amper-ometry and amperometric measurements made in response to a variety of applied potential waveforms in voltammetric methods. Impedimetric methods comprise a final classification in these methods, faradaic currents are generally absent, and impedance, conductance, or capacitance is the measured property. 

A large number of electrochemical methods exist which are or have the potential to be useful in the study of reactive intermediates. The methods are conveniently categorized according to the quantity measured, usually the current, potential, or some optical property of the reactants or the intermediates. A further classification arises from the manner in which experiments are conducted, i.e. transient or steady state measurements. In this brief survey only those techniques which have been reduced to useful practice are discussed and even then the coverage is not exhaustive. More detailed discussion can be found in several excellent references sources (Bard, 1966-present MacDonald, 1977 Bard and Faulkner, 1980). 

Goals of Testing and Classification of Test Methods Nonelectrochemical Methods Electrochemical and Electrical Methods Barrier Characteristics of Coatings Adhesion of Organic Coatings Transport Properties of Coatings Other Film Properties Corrosion Resistance of Painted Metals... 

Refs. [i] Kolthoff IM, Lingane JJ (1952) 2nd edn. Polarography. Polarographic analysis and voltammetry. Amperometic titrations. Interscience, New York, vol. 2, pp 887 [ii] Heyrovsky J, Kuta J (1966) Principles of polarography. Academic Press, New York, pp 267 [Hi] Classification and nomenclature of electroanalytical techniques (1976) Pure Appl Chem 45 81 [iv] Bard AJ, Faulkner LR (2001) Electrochemical methods, 2nd edn. Wiley, New York, pp 437... 

The classification of chemical structure using electrochemical techniques, is a challenging problem. Voltammetric responses lack fine structure and probably will never compete with spectroscopic methods in qualitative analysis. The complex dependence of an electrochemical response on many variables, and theoretical... 

Classification of macrocyclic compounds containing tetrathiafulvalene moieties, synthetic methods, the latest advances in research on electrochemical properties and applications to molecular recognition and development trends in research on such macrocyclic compounds were outlined and reviewed <2007MI1220>. 

As intensive studies on the ECPs have been carried out for almost 30 years, a vast knowledge of the methods of preparation and the physico-chemical properties of these materials has accumulated [5-17]. The electrochemistry ofthe ECPs has been systematically and repeatedly reviewed, covering many different and important topics such as electrosynthesis, the elucidation of mechanisms and kinetics of the doping processes in ECPs, the establishment and utilization of structure-property relationships, as well as a great variety of their applications as novel electrochemical systems, and so forth [18-23]. In this chapter, a classification is proposed for electroactive polymers and ion-insertion inorganic hosts, emphasizing the unique feature of ECPs as mixed electronic-ionic conductors. The analysis of thermodynamic and kinetic properties of ECP electrodes presented here is based on a combined consideration of the potential-dependent differential capacitance of the electrode, chemical diffusion coefficients, and the partial conductivities of related electronic and ionic charge carriers. 

An alternative and electrochemically more significant method for classification of electroorganic reactions is based upon the type of mechanism of the electrode process. This may be described in terms of the number and sequence of electrochemical steps (involving the transfer of electrons) and chemical steps. A useful example of both types of classification is the electrooxidation of an aliphatic amide, e.g., AW-dimethylformamide ... 

Conductometric sensors, measuring the variatimi of the solution conductance due to electrical charge concentrations changes. The method is simple but not selective, since the conductance depends on the ionic concentration of all of the present species. In view of the fact that no electrochemical processes take place, conductometric sensors are not strictly electrochemical ones. They are considered, according to lUPAC chemical sensors definitions and classification [1], as a subclass of electrical devices in which the signal results from the change of electrical properties caused by the interaction of the analyte. Nevertheless, electrical devices are frequently put into one category with the electrochemical devices [1]. 

A lot of synthetic effort has been devoted to the synthesis of polymerizable thiophene derivatives, but the principal aim of this review is to focus on the polymerization chemistry. The basic synthesis procedures for polythiophene can be considered in parallel with poly(p-phenylene). Indeed, a similar classification can be drawn direct oxidation of thiophene, organometallic coupling, and electrochemical syntheses. Frecursor methods for polythiophene are rather exceptional. 

Considering that molecular recognition generally uses well-defined reaction types and that the deletion method may be extremely varied, it is logical that biosensors should be classified primarily as a function of the bioreceptor used. However, a laboratory that only ever worics with enzymes, for example, could use a classification according to the transducer employed (electrochemical, thermometric, etc). In what follows, we have opted to use the classification by bioreceptor because this component determines the primary action of the biosensor. 

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