Anodic stripping voltammetry using a vibrating electrode

This work proposes a vibrating microwire electrode as working electrode in stripping voltammetry. The vibration was found to maintain a constant and thin (1 -2 mu m) diffusion layer during the deposition step. The electrode vibration eliminated the need for external stirring of the solution, thus facilitating in situ detection in the environment. The vibration was effected by fixing a low-voltage (3 V), asymmetric, electrical rotor to the working electrode (a gold microwire of either 5 or 25 mu m). The sensitivity of the vibrated electrode was ca. 22 x greater than stationary. Measurements of copper (4 nM) by anodic stripping voltammetry using the vibrating electrode had a low standard deviation (1% for n = 6) indicating that the diffusion layer had only minor variability. The agitation mechanism was unaffected by water moving at > 2 m s(-1) and by water pressure equivalent to a depth of > 40 m, indicating its suitability for in situ measurements. The vibrating probe was used for in situ detection of copper by anodic stripping voltammetry to a depth of 6 m. Using a 5 min deposition time, the limit of detection for labile copper was 38 pM.