Ion Exchange Resin Modified Carbon Paste Electrode Applied to Simultaneous Determination of Cd (II) and Pb (II)

Abstract

A new, simple, sensitive and fast analytical method was developed to simultaneous quantification of Cd(II) and Pb(II) in cooling water by anodic square wave redissolution voltammetry (SWASV) using a modified carbon paste electrode composite with carbon black, resin functionalized with sulphonic group and paraffin. The experimental conditions such as supporting electrolyte (composition, pH and ionic strength) and SWASV parameters were optimized. The best conditions of Cd(II) and Pb(II) (higher peak current) were obtained in 0.1 mol l−1 BR buffer (pH 4.6) from −1.1 to 0.3 V, amplitude of 60 mV, frequency of 40 Hz, potential step of 5 mV, potential and deposition time of −1.1 V and 240 s, respectively. The analytical curve of Cd(II) and Pb were linear from 10 to 50 μg l−1 (R2 = 0.999) with quantification limit of 0.06 and 0.12 μg l−1, respectively. The method was successfully applied in cooling water from thermoelectric industry and the concentrations of Cd(II) and Pb(II) were 3.27 ± 0.30 and 2.80 ± 0.18 mg l−1, respectively. The method accuracy was evaluated through the comparison with the comparative method (SWV with Hanging Mercury Drop Electrode) and the relative error obtained was smaller than 9.8%.