Array of peptide-modified electrodes for the simultaneous determination of Pb(II), Cd(II) and Zn(II)

This paper reports the development of three peptide modified sensors in which glutathione (GSH) and its fragments Cys–Gly and γ-Glu–Cys were immobilized respectively through aryl diazonium electrochemical grafting onto the surface of graphite–epoxy composite electrodes (GEC), and used for the simultaneous determination of Cd(II), Pb(II) and Zn(II). The concentration interval ranged from 0.1 to 1.5 μmol L−1 for each metal, and the technique used was differential pulse adsorptive stripping voltammetry. This study aimed to the comparison of the information provided by one single modified electrode at both fixed and multiple pH values (pH 6.8, 7.5 and 8.2) for the simultaneous determination of the three metals, with those supplied by the three-sensor array at multiple pH values. For the processing of the voltammograms, the fast Fourier transform was selected as the preprocessing tool for data compression coupled with an artificial neural network for the modeling of the obtained responses.