Evolving polynomial regression and error analysis in model identification and determination of consecutive stability constants using voltammetric methods

Error analysis in polarographic model identification and stability constant determination of consecutively formed complexes has been performed on simulated data. On the basis of the results obtained on simulated data several constraints have been proposed in order to obtain more reliable model identification and stability constants having physico-chemical meaning. Ledenʹs function extrapolation has been optimized using least squares in order to minimize the possible cumulative errors. Evolving polynomial regression has also been proposed as a method for better model identification. The proposed procedure was tested on experimental data of Pb(II) and Cd(II)-propanoate, measured using differential pulse polarography in aqueous solution of constant ionic strength of 2 M (NaClO4) and constant temperature of 25 ± 1 °C. An evaluation of the data for the Cd(II)-thiocyanate system published in the literature has also been attempted.