Research Article
Studies on Synthetic and Natural Melanin and Its Affinity for Fe(III) Ion
Table 3
Equilibrium constants for the interactions of natural melanin-Fe(III)*.
| Equilibrium | (SD) |
| Fe(Ac)]2+/[Fe3+][Ac−] | 5.20 (0.20) | Fe(Qi)2+]/[Fe3+][Qi−] | 5.73 (0.22) | Fe(OH)(Cat)][H+]/[Fe3+][Cat2−] | 23.53 (0.18) | Fe(OH)(Cat)(Qi)−]/[Fe(OH)(Cat)][Qi−] | 5.66 (0.15) | Fe(OH)2(Cat)(Qi)2−][H+]/[Fe(OH)(Cat)(Qi)−] | −8.89 (0.05) | ][H+]/[Fe(OH)(Cat)][Cat2−] | 4.1 (0.08) |
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*Obtained by fitting the average of three or more titrations.
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