Electrochemical Studies of Progressively Alkylated Thiazine Dyes on a Glassy Carbon Electrode (GCE) in Water, Ethanol, and Triton X-100 Media

Abstract

Cyclic voltammetric investigations have been performed on the clean glassy carbon electrode (GCE) at (25 ± 0.1) °C on five progressively alkylated thiazine dyes, namely, thionine (Th), methyl thionine (Azure C), dimethyl thionine (Azure A), trimethyl thionine (Azure B), and tetramethyl thionine (methylene blue) in water, water−ethanol, and water−Triton X-100 media. Diffusion coefficient values of the dyes, measured from the electrochemical data in different media, are clearly influenced by the effect of progressive alkylation to the thionine moiety along with the solvent property. In aqueous media the values of diffusion coefficient fall in the range of (2.66·106 to 5.70·106) cm2·s−1, whereas in presence of ethanol and Triton X-100 the rather lower ranges of (1.16·106 to 3.70·106) cm2·s−1 and (0.76·106 to 1.80·106) cm2·s−1 are observed, respectively. At higher pH’s the voltammograms display cathodic and anodic post/prepeaks which are the characteristics of the strong adsorption of reactants and/or products. Along with different electrochemical parameters the kinetic parameters of electrode processes have also been determined.

Chronoamperometric and morphological investigation of nucleation and growth mechanism of poly(azure A) thin films

“…This result exhibits that electropolymerization of AA is associated with the surface process. Similar results have been determined in previous studies [22,41] Potentiostatic j-t transients fitted to theoretical model [42] for electropolymerization process of AA provides a useful information about nucleation and growth mechanism. J-t transients were obtained by keeping the potential of working electrode constant at various oxidation potentials of AA.…”

Unsubstituted phenothiazine as a superior water-insoluble mediator for oxidases

“…However, the values obtained are comparable to the values for typical azine-type mediators measured in water-ethanol mixtures (1.8 -3.7 × 10 -6 cm 2 s -1 ) (Chakraborty et al 2010) and comparable to the value of the diffusion coefficient for Methylene Blue in aprotic solvent 6.2 × 10 -6 cm 2 s -1 (Wopschall and Shain 1967).…”

Cyclic Voltammetric Investigations of Thiazine Dyes on Modified Electrodes

“…The electrochemical behavior of five thiazine dyes ( Figure 1) on a bare GCE has already been reported elsewhere [25]. But in clay-modified electrodes thiazine dye cation seem to be adsorbed strongly by clay minerals.…”