Fabrication of an Electrode from EDTA-Modified Graphite Paste for Determining the Concentration of Lead Ions Using Differential Pulse Anodic Stripping Voltammetry Technology (DPASV).

Abstract

This research addressed the fabrication of a selective electrode for determining the trace concentrations of lead ions (Pb²⁺) in aqueous solutions, based on graphite paste modified with ethylene diamine tetra acetic acid (EDTA), which was mixed with graphite and paraffin oil. The optimal proportions were found to be (10%, 45%, 45%), respectively. The electrical response and peak saturation current of lead were studied using anodic cumulative differential pulsed voltammetry (DPASV). Analytical conditions were investigated, and the appropriate electrolyte (HCl, CH₃COONa, CH₃COONH₄) and pH were selected. The optimal was found to be (CH₃COONa at pH = 8). the optimal technical conditions for Pb²⁺ determination were tested and determined, pulse amplitude, pulse duration, potential step, and potential step time:

(0.11 V ,0.01 S, 0.009 V, 0.2 S). The validity and accuracy were established by calculating the recovery value (R% = 100.5%), the standard deviation (SD = 0.040 ppm), the relative percent standard deviation (RSD% = 1.97%), and a confidence interval of (0.1004 ± 0.0497) within a confidence level of (95%). The Quantitative detection limit was (0.100 µg/l) and the limit of detection was (0.080 µg/l).