Comparative Study to Evaluate the Feasibility of Sono-Anodic and Sono-Cathodic Stripping Voltammetry for the Determination of Pb in a Cu-Pb Alloy

Abstract

The complicated analytical challenge of lead determination in the presence of high levels of copper, has been investigated using anodic and cathodic stripping voltammetry, on a variety of mercury free electrode substrates. CSV was found to be ideally suited towards lead determination in a predominantly copper matrix, due to the lack of interference from copper ions on the anodic electrochemistry of lead. A CSV technique, incorporating the use of power-ultrasound and a borondoped diamond electrode is presented. The sono-CSV technique has been optimised to give a lower limit of detection of aqueous Pb 2+ ions of 1.6×10 -9 M for a 300 s PbO2 deposition, requires no solution degassing, is mercury-free and totally free from copper-intermetallic interference. As an extreme example, the technique was applied successfully to the determination of lead content of a copper-lead alloy, after a simple acid digestion protocol. Excellent correlation was observed between the known lead level and experimental results, with the technique being sensitive towards the detection of 3.3×10 -4 % (w/w) lead in copper, for the analysis of a 10 mg sample.

Electroanalysis at Diamond‐Like and Doped‐Diamond Electrodes

“…In processes in which −extreme× conditions are applied to electrochemical systems, e.g., in the presence of power ultrasound or laser activation, borondoped diamond is often the only choice. Review of potential application, flow injection studies [106] Sulfa drugs (sulfadiazine, sulfamerazine, sulfamethazine) detection procedure based on boron-doped diamond HPLC post-column amperometric detection [116] tRNA [131,132,133,134] Ag by anodic and cathodic stripping voltammetry Sonovoltammetry [135] …”

“…CSV was found to be ideally suited towards lead determination in a predominantly copper rich matrix, due to the lack of interference from copper ions on the anodic electrochemistry of lead. A CSV technique, incorporating the use of power-ultrasound and a boron-doped diamond electrode was proposed [134]. The sono-CSV technique has been optimized to give a lower limit of detection of aqueous Pb 2 ions of 1.6 Â 10 À9 M for a 300 s PbO 2 deposition, requires no solution degassing, is mercury free and totally free from copper-intermetallic interference.…”

Electrodeposition of Lead at Boron‐Doped Diamond Film Electrodes: Effect of Temperature

“…A number of electrochemical techniques have been proposed for its direct detection in aqueous solutions of environmental samples, based on electrodeposition of the reduced metal [1 ± 4] or its oxides [3,5,6]. These have proved very suitable for trace analysis and are compatible with portable equipment [7] such as is desirable in environmental monitoring.…”

“…It is for these reasons that interest in the material for use in various electrochemical processes has been growing steadily since the middle of the 1980s [15]. These unique properties of BDD make it ideally suited for stripping voltammetry analysis of Pb, Mn, Cd, Cu and Ag [2,3,5,6,13,16] particularly in terms of elimination of background current interferences.…”

“…A current crossover is therefore observed. Such voltammetric behavior is characteristic of a nucleation and growth mechanism [3,15,18] in which the initial formation of Pb nuclei on the diamond surface serves to increase the rate of further deposition. Thus on the return scan the cathodic current flows at less negative potentials than these required to initiate deposition.…”