Copper-bismuth-film in situ electrodes for heavy metal detection

This work presents the development and validation of 8 new in situ bismuth-copper-film electrodes (BiCuFEs) for Zn(II), Cd(II), and Pb(II) trace analysis in 0.1 M acetate buffer. The BiCuFEs were compared with in situ copper-film (CuFE) electrodes - new electrodes that have recently been reported. The formation of every in situ electrode was performed at two different concentrations, i.e. 0.5 and 1.0 mg/L. All BiCuFEs were selective for Zn(II), Cd (II), and Pb(II) determination. By using different BiCuFEs, the lower limit of the linear concentration ranges for Zn(II), Cd(II), and Pb(II) was generally lower compared with those for the CuFEs. Moreover, the BiCuFEs were generally more sensitive and had lower limits of detection for Zn(II), Cd(II), and Pb(II) determination than the CuFEs. The precision of the methods and the precision of the systems were satisfactory for the vast majority of the electrodes tested (RSD < 20.0%). For selected BiCuFEs a possible interference effect on the stripping signals of the analytes was checked in the presence of Fe(II), As(III), Na(I), K(I), Ca(II), Mg(II), Sn(II), Sb(III), and NO3 in water solution. Moreover, electrochemical impedance spectroscopy measurements were performed in order to determine if the electroanalytical system is under a kinetic-controlled or mixed kinetic- and diffusion-controlled process. Furthermore, the applicability of the selected BiCuFEs was confirmed by real water sample analysis.