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Mechanism of the electrochemical reduction of tetrazolium blue in non-ionic micelles

1990; Elsevier BV; Volume: 282; Issue: 1-2 Linguagem: Inglês

10.1016/0022-0728(91)85098-a

2590-2954

Maria Isabel Viseu, M.L.S. Simões Gonçalves, Sı́lvia M. B. Costa, Maria Isabel C. Ferreira,

Advanced biosensing and bioanalysis techniques

A mechanism is proposed for the electrochemical reduction of tetrazolium blue (TB2+ ) on the surface of a dropping mercury electrode. The reaction was performed in a heterogeneous solvent: non-ionic micelles of Triton X-100, in an aqueous buffer solution, at pH 7.0. The mechanism, deduced from polarographic data, was found to consist of: (i) two irreversible diffusion-controlled processes, each one with two electrons transferred; and (ii) at least two more electron-transfer paths in which one or both of the oxidized and reduced species are adsorbed on the electrode. The oxidation-reduction potentials obtained for the two redox pairs involved (TB2+/TBH+ and TBH+/TBH2) are −0.134 and −0.709 V, respectively, versus a standard hydrogen electrode.