engleski

Application of a fourier transform method to the resolution enhancement of adsorption peaks in differential pulse polarography

A Fourier transform method is used for the resolution enhancement of the closely overlapping diffusion-controlled main peak and the post-peak caused by adsorption in differential pulse polarography (DPP). The method is tested on a theoretical model. Complex DPP responses influenced by the reactant adsorption which follows Frumkin's isotherm are simulated. By varying the reactant bulk concentration and parameter responsible for the strength of adsorption and the interaction between molecules and adsorbed reactant, sets of theoretical current-potential curves are obtained on which the proposed method consisting of deconvolution of the signal in the Fourier domain by the appropriate deconvolution function is applied. The post-peak of the transformed signal is narrower than in the original DPP responses, and consequently better separated from the transformed main peak. However, the transformation does not alter the peak potentials of both the main and the post-peak. The result of this investigation is the region of a contribution of the method, i.e. conditions under which the adsorption process only after deconvolution can be detected and defined. The method is proved useful for the detection of chloride-induced adsorption of Pb(II) ions to the surface of the mercury electrode at the potentials of the lead ion reduction.

adsorption ; resolution enhancement ; DPP ; FFT ; deconvolution

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