An investigation of the interaction between resazurin and Cd2+ and Zn2+ ions in aqueous medium
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 β1:1 = 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.
| Main Authors: | , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
The South African Chemical Institute
2010
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| Online Access: | http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0379-43502010000100023 |
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