Convolution-deconvolution cyclic voltammetric equilibria study on cadmium(II)-L-histidinate in aqueous solutions

POLAG computer programme was employed for processing convoluted-deconvoluted cyclic voltammetric data to study cadmium(II)-L-histidinate system. This was performed in 0.1 mol/dm(3) NAClO(4) aqueous solution at different pH's at 298K. The results show that the reduction of cadmium(II) and its complexes proceeds via a reversible and diffusion-controlled wave of two electrons at the entire range of pH. The system was studied at two ranges of pH (6.73-7.44 and 8.53-8.92). It was evident that the system at the first range of pH is well described by the presence of a mixture of binary complexes, Cd(HisO.H)], Cd(HisO.H(2))(2)] and a ternary one Cd(HisO.H)(HisO.H(2))]. For the second pH range, it was revealed that the most likely model corresponds to the presence of a mixture of Cd(HisO)(2)] and Cd(OH)] species. The overall stability constants were computed. The structure of the detected complexes was discussed on the basis of ligating sites of histidine.