Voltammetry, cyclic pulsed

The Model 384B (see Fig. 5.10) offers nine voltammetric techniques square-wave voltammetry, differential-pulse polarography (DPP), normal-pulse polar-ography (NPP), sampled DC polarography, square-wave stripping voltammetry, differential pulse stripping, DC stripping, linear sweep voltammetry (LSV) and cyclic staircase voltammetry. 

Many of the electroanalytical techniques that are routinely employed in conventional solvents, such as, chronoamperometry, chronocoulometry, chronopotentiometry, coulometry, cyclic (stationary electrode) voltammetry, rotating electrode voltammetry, and pulse voltammetry, have also been applied to molten salts. Some of these techniques are discussed next with special attention to their employment in molten salts. References to noteworthy examples appearing in the literature are included. Background information about these techniques is available elsewhere in this book. 

Potentiodynamictechniques— are all those techniques in which a time-dependent -> potential is applied to an - electrode and the current response is measured. They form the largest and most important group of techniques used for fundamental electrochemical studies (see -> electrochemistry), -> corrosion studies, and in -> electroanalysis, -+ battery research, etc. See also the following special potentiodynamic techniques - AC voltammetry, - DC voltammetry, -> cyclic voltammetry, - linear scan voltammetry, -> polarography, -> pulse voltammetry, - reverse pulse voltammetry, -> differential pulse voltammetry, -> potentiodynamic electrochemical impedance spectroscopy, Jaradaic rectification voltammetry, - square-wave voltammetry. 

Misonidazole and its azo- and azoxy derivatives have been investigated in detail by polarography, cyclic voltammetry, and pulse radiolysis methods [947],... 

Table 8. One-electron reduction potentials (in V vs. Fe /Fe) for radical cations measured by cyclic voltammetry and pulse radiolysis.

Electrochemical indicator methods are based on the use of a redox probe that undergoes an oxidation and reduction transition due to electron transfer from an electrode surface to a probe. In 2005, several papers were published that used methylene blue (MB) as an electrochemical indicator. Methylene blue is a positively charged low-molecular-mass compound that can be reduced by two electrons to leucomethylene blue (LB). The reduction process can be monitored effectively by differential pulse voltammetry, cyclic voltammetry, or coulometry. In the presence of a redox probe Fe(CN)g, the LB is oxidized to MB and system is regenerated (Boon et al., 2000 Ostatna et al. 2005). In papers of Hianik et al. (2005, 2007) the MB was used as an indicator for the detection of interaction of human thrombin with DNA aptamer. The method of detection is shown... 

Recently, electroanalysis of Cd-complexation with different mammalian MTs (e.g., rabbit fiver, horse kidney, and human kidney) has become more frequent. The study of cysteine-containing peptides such as glutathione and MTs peptidic fragments (mainly a-domain of mammalian MTs), in the absence and in the presence of Cd, has been carried out by means of several electrochemical techniques such as differential pulse polarography (DPP), linear sweep voltammetry, cyclic voltammetry, direct current... 

The above treatment assumes that the measured reduction potentials are thermodynamically meaningful. Although redox potentials can be measured by a variety of electrochemical techniques, cyclic voltammetry, differential pulse polarography, and more recently, square wave voltammetry have found the greatest use because of the ability of these techniques to reveal the dynamics of the associated chemical processes, and hence access the chemical and electrochemical reversibility of the couple. Chemical and electrochemical reversibility have been defined and problems associated with the distinction between these terms have been covered in Chapter 2.15 (2.15.2.2.1), however, for the purpose of this discussion it is useful to treat these behaviors separately. 

R. M. Wightman The technique that we use is normal pulse voltammetry with pulses that are 100 ms long. But in the last 6 months, working with some people at the London hospital we have been using very fast cyclic voltammetry, at 300 V/s and we can get a complete record in 10 ms it gives exactly the same quantitative numbers as 1 showed here. So that is the direction in which certainly all of us will be going. 

Bioelectrochemistry has benefited from the development of several new electroanalytic techniques like cyclic voltammetry or pulse voltammetry in the second half of the twentieth century. These technologies allowed solid macro- and microelectrodes of various materials to be used for the elucidation of electron transfer processes on various electrode materials. To overcome mass-transfer limitation rotating disc electrodes or flowcells for stationary electrodes have been developed. Cyclic voltammetry is the... 

Electroanalytical methods have been extensively applied in sensing and biosensing. Potentiometry, amperometry, cyclic voltammetry, linear voltammetry, differential pulse voltammetry, square-wave voltammetry, and electrochemical impedance spectroscopy (EIS) represent the most-used electrochemical techniques used for biosensor fabrication and detection. 

The determination of the antioxidant capacity is based on the current generated by the electrochemical reduction of DPPH during analysis. Since the current is proportional to DPPH concentration, it is possible to evaluate the percentage of DPPH consumed by the antioxidant. Therefore, the analysis of antioxidant capacity is achieved by the decrease in the DPPH current measured at a constant potential selected by the cyclic voltammetry study (or by the hydrodynamic voltammogram). The current analysis can be performed by various electrochemical techniques, such as cyclic voltammetry, differential pulse voltammetry, and amperometry. 

Determined by direct electrochemistry at a glassy carbon electrode (cyclic, differential pulse, or square-wave voltammetry). 

---