Voltammetric techniques platinum-working electrode

In voltammetric techniques the auxiliary electrode, which is placed directly in the solution under study (see the next section), is usually made of platinum wire that is coiled around the working electrode. In contrast,... 

Voltammetry. The voltammetric techniques are based on the current-voltagetime relationship at microelectrodes. To perform voltammetry, the oil/antioxidant sample is dissolved in a solvent containing an electrolyte and a three-electrode system (glassy carbon working electrode, a platinum wire reference electrode, and platinum wire auxiliary electrode) is inserted into an oil/solvent solution. A fresh oil typical of the application (100% standard) and the solvent system (0 % standard) is used to calibrate the voltammetric instrument for % remaining antioxidant determination (Kauffman, 1989 and 1991). 

The simplest way to assist electrochemical techniques with US is by using a bath to immerse the electrochemical cell, as proposed by Lorimer et al. [154] (see Fig. 8.15A). These authors used a three-compartment thermostated voltammetric cell consisting of a platinum flag (the counter electrode), a saturated calomel electrode (the reference electrode) and a rotating disc (the working electrode). Although an ultrasonic bath affords less accurate control of US irradiation, it affords a tenfold current increase in sonovoltammetry [167]. 

Amperometric and voltammetric biosensors rely on an electrochemically active analyte that can be oxidized or reduced at a working electrode. Typical electrode materials are platinum (Pt), gold (Au), and carbon. Nowadays some innovative techniques for electrode preparation, characterized by the possibility of mass production and high reproducibility, have been proposed. Among these, the equipment needed for thick-film technology is less complex and costly, and thus, this is one of the most used for sensor production. Thick-film technology consists of depositing inks on a substrate in a film of... 

Although one of the more complex electrochemical techniques [1], cyclic voltammetry is very frequently used because it offers a wealth of experimental information and insights into both the kinetic and thermodynamic details of many chemical systems [2]. Excellent review articles [3] and textbooks partially [4] or entirely [2, 5] dedicated to the fundamental aspects and applications of cyclic voltammetry have appeared. Because of significant advances in the theoretical understanding of the technique, today, even complex chemical systems such as electrodes modified with film or particulate deposits may be studied quantitatively by cyclic voltammetry. In early electrochemical work, measurements were usually undertaken under equilibrium conditions (potentiometry) [6] where extremely accurate measurements of thermodynamic properties are possible. However, it was soon realised that the time dependence of signals can provide useful kinetic data [7]. Many early voltammetric studies were conducted on solid electrodes made from metals such as gold or platinum. However, the complexity of the chemical processes at the interface between solid metals and aqueous electrolytes inhibited the rapid development of novel transient methods. 

---