A mercury free electrode for anodic stripping voltammetric determination of Pb (II) ions using poly zincon film modified electrode

With an aim of developing a mercury-free electrode for anodic stripping voltammetric determination of Pb (II) ions, a poly zincon film (PZF) modified electrode is reported here. The PZF on the electrode surface has been obtained by electropolymerisation of zincon. PZF present on the electrode surface has been used for preconcentrating Pb (II) ions through complexation. The electrochemical determination of the above metal ion has been carried out by reducing the preconcentrated Pb (II) at -1.0 V followed by anodic stripping in acetate buffer of pH 6 and measuring the stripping current at -0.64 V. The PZF and Pb pre concentrated PZF modified electrodes have been characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The factors influencing the determination of Pb (II) ions such as the nature of medium/background electrolyte, pH, preconcentration time and electrode regeneration have been studied in detail. Under optimum conditions, a linear relation for the stripping current with Pb (II) ions in the solution has been observed in the range from 3.45 to 136.3 mu g L-1 with a detection limit of 0.98 tig L-1. The regeneration of the modified electrode after each experiment has been achieved by simply immersing the electrode in 0.1 M EDTA solution for 2 min and washing thoroughly in de-ionised water. PZF modified electrode has shown a promising and sensitive platform for the anodic stripping determination of Pb (II) ions and the regeneration of the electrode has been found to be easy for subsequent uses. The proposed method has been applied for the determination of Pb (II) ions in ground water and tap water samples. (C) 2017 Elsevier B.V. All rights reserved.