Voltammetry of Pb(II), Cd(II) and Zn(II) ions in the presence of the sulphated polysaccharide λ-carrageenan

A systematic study of the voltammetric redox processes of Pb(II), Cd(II) and Zn(II) in the presence of λ-carrageenan has been made by normal pulse, reverse pulse, and differential pulse polarography, as well as by differential pulse anodic stripping voltammetry. Titrations of metal ions with λ-carrageenan allow the determination of the global formation constant of each system and their dependences on KNO3 (supporting electrolyte) concentration and pH values. Reversibility of the redox couples M(II)M(Hg) is not strongly affected by the presence of λ-carrageenan, which gives small non-Faradaic signals. In the time scale of used techniques M(II)/λ-carrageenan systems seem to be of labile nature.