Voltammetric determination of copper(II) ion using cyanex 921 modified pencil graphite electrodes

Abstract

In this study, polymer-based modified electrodes (PGE/PPy and PGE/PPy/Cyanex 921) based on pencil graphite electrodes (PGE) have been prepared for the determination of copper(II) ions. Parameters such as the number of cycles, scan rate, and solution pH have been optimized to prepare the electrodes. As a result of the analyses, the optimum number of cycles is determined to be 8 for the PGE/PPy and PGE/PPy/Cyanex 921 electrodes. The scan rate is 40 mV/s for PGE and 80 mV/s for PGE/PPy and PGE/PPy/Cyanex 921 electrodes. The pH value of the analysis medium is set to 2 for both the PGE and PGE/PPy electrodes and 3 for the PGE/PPy/Cyanex 921 electrode. The electrodes are prepared using the cyclic voltammetry (CV) technique. The performance of the electrodes in the determination of copper(II) ions was investigated using the differential pulse voltammetry (DPV) method. As a result of experiments with the electrodes, linearity is obtained in the ranges of 20–200 ppm (R²=0.9991) for the PGE electrode, 20–150 ppm (R²=0.9983) for the PGE/PPy electrode, and 20–140 ppm (R²=0.9991) for the PGE/PPy/Cyanex 921 electrode. The limits of detection (LOD) for the PGE, PGE/PPy, and PGE/PPy/Cyanex 921 electrodes are found to be 3.60, 3.51, and 2.15 ppm, respectively (S/N=3). Interference effect experiments showed that the selectivity and sensitivity of the PGE/PPy/Cyanex 921 electrode for copper(II) are not significantly affected by the presence of interfering species. The developed electrodes are used to determine copper(II) ions added to water samples by the standard addition method, and the recovery values of the method were close to 100%.