Collect. Czech. Chem. Commun. 1991, 56, 96-103

Stripping voltammetry of zinc/polyacrylate complexes: Influence of molar mass

Marc A. G. T. Van den Hoop, Francisco M. R. Leus and Herman P. Van Leeuwen

Laboratory for Physical and Colloid Chemistry, Wageningen Agricultural University, Dreijenplein 6, 6703 HB Wageningen, The Netherlands


Differential pulse anodic stripping voltammetry (DPASV) has been applied to complex systems of zinc(II) and polyacrylic acid (PAA) for various molar masses of the polyacid. The Zn/PAA complex is voltammetrically labile over the whole range of metal-to-ligand ratios. Analysis of the data in terms of a mean diffusion coefficient, which decreases with increasing molecular mass, yields a consistent picture with molar mass-independent complex stabilities. The speciation of Zn(II) in such a polyelectrolyte system varies with the concentration of carboxylate groups and with the overall charge of the PAA, but it is invariant with the polyionic molar mass.