Abstract

ARSLAN, Emine Yimaz  and  CAKIR, Semiha. An investigation of the interaction between resazurin and Cd²⁺ and Zn²⁺ ions in aqueous medium. S.Afr.j.chem. (Online) [online]. 2010, vol.63, pp.152-157. ISSN 1996-840X.

The voltammetric behaviour of resazurin in the presence of Cd²⁺ and Zn²⁺ ions at a hanging mercury drop electrode (HMDE) was investigated by using square wave voltammetry (SWV), cyclic voltammetry (CV) and adsorptive square wave voltammetry (AdsSWV). The interaction of resazurin with Cd²⁺ and Zn²⁺ starts above pH 4 and seems to be completed at pH 5.2 with Cd²⁺ ions and at pH 7.5 with Zn²⁺ ions. A new peak appears at -0.93 V in the presence of Cd²⁺ and at -1.07 V in the presence of Zn²⁺. These peaks may be attributed to M²⁺-resazurin complexes and the logarithm of their stability constant was determined where log β₁₄ = 4.22 for Cd²⁺-resazurin and log β_1:1 = 4.74 for Zn²⁺-resazurin. Cyclic voltammetry was used to characterize the redox mechanism and to calculate voltammetric data of M²⁺-resazurin complexes. The amount of adsorbed M²⁺-resazurin complexes on the mercury drop electrode surface (Γ) is calculated as 5.48 x 10^-12 mol cm^-2 for Cd²⁺-resazurin and 1.10 x 10^-11 mol cm^-2 for Zn²⁺-resazurin. The voltammetric data were compared with the data obtained using spectrophotometric methods and were observed to be in good agreement.

Keywords : Resazurin; cadmium; zinc; electrochemistry; spectroscopy; metal complexes.

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