Optimisation of resolution function in signals ratio method and deconvolution by polynomial division – quantitation of Cd(II) and In(III) from their global signals obtained at carbon fibre disk ultramicroelectrode

Abstract

In order to investigate the applicability of the carbon fibre disk ultramicroelectrode (CFDUME) as a global electrochemical sensor for metal ions, several resolution methods have been tested for quantitation of Cd(II) and In(III) ions in their mixture. The signal ratio resolution method, as well as conventional deconvolution and deconvolution by fast Fourier transform have been compared using signals from different mixtures of Cd(II) and In(III) ions, obtained by differential pulse anodic stripping voltammetry (DPASV) at CFDUME. For the first two methods an efficient parameter is introduced which we named parameter of the difference between the mean of the mean of absolute and non-absolute values of pseudo-signals (or deconvoluted signals), PDMMV (PS). Using many different resolving functions, this parameter enables to select the optimised one, obtaining therefore reliable concentrations, independent of the resolving signal used. Fourier transform deconvolution was also compared, but in its conventional form, it seems to be unsuitable for quantitation because it introduces deconvolution noise which is too high. The PDMMV parameter was tested on simulated differential pulse polarographic data and experimental DPASV results.