Highly Sensitive Detection of Cd2+ Using Boron Doped Diamond Electrodes

The electrochemical detection of Cd2+ has been performed by anodic stripping voltammetry on boron doped diamond (BDD) electrodes. A new technique is proposed, which involves adding a known amount of copper to the sample to deposit an amalgam of Cd-Cu on the surface of the BDD electrode. This amalgam is then stripped during voltammetry measurements, allowing the generation of highly accurate calibration curves for Cd detection (r(2) = 0.99) with a lower detection limit of 10 ppb. The conditions that are used for the anodic stripping voltammetry measurements have been optimized to avoid the deposition of cadmium and the appearance of the stripping peak related to copper. Real samples could contain a certain amount of copper, so the influence of small variations of Cu2+ concentration has been investigated and it was found that such variations have no influence on the accuracy of the calibration curve for Cd detection. The influence of other metals that could be dissolved in the sample has also been studied, and it was shown that lead and selenium have a negative influence on the technique. However, this negative interference can be eliminated by increasing the concentration of copper that is introduced in the sample. Furthermore, other species such as boron or chromium have no influence on the anodic stripping voltammetry measurements, so accurate calibration curves for Cd determination could be constructed in the presence of Pb, Se, B and Cr. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.080111jes] All rights reserved.