Graphic Data Analysis and Complex Formation Curves as Modelling and Optimization Tools in Potentiometric and Voltammetric Speciation Studies of a Pb(TAPSO)x(OH)y System

• Published in: Electroanalysis (New York, N.Y.) Vol. 17; no. 14; pp. 1291 - 1301
• Main Authors: Machado, Carina M. M., Cukrowski, Ignacy, Soares, Helena M. V. M.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.07.2005; WILEY‐VCH Verlag
• Subjects: 3-[N-Tris(hydroxymethyl)methylamine]-2-hydroxypropanesulfonic acid; Biological buffer; Lead; Stability constants; TAPSO
• ISSN: 1040-0397; 1521-4109
• DOI: 10.1002/elan.200403244

The formation of complex species between lead and TAPSO, a commercialized biological buffer, was evidenced and discussed. Formation constants of Pb(TAPSO)x(OH)y system have been studied by direct current polarography and by glass electrode potentiometry at fixed total–ligand and total–metal concentration ratio and varied pH, at 25.0 °C and ionic strength set to 0.1 M KNO3. The graphic analysis revealed to be a very powerful tool in the prediction and refinement operations of Pb–(TAPSO)x(OH)y system. The proposed final model for this system is: PbL, PbL2, PbL2(OH) and PbL2(OH)2, with stability constants values, as log β, of 3.7±0.1, 6.6±0.1, 12.9±0.1 and 17.8±0.1, respectively.