A vibrating membrane working electrode for highly sensitive anodic stripping voltammetry

Anodic stripping voltammetry (ASV) is an effective electrochemical method for quantitative determination of ions in solution. In this work, we present a new vibrating working electrode for the ASV detection of copper ion. This working electrode is a thin multilayer membrane consisting of a gold film working electrode evaporated on a piezoelectric resonant diaphragm. Chemical vapor deposition and electron beam evaporation methods are used to form multiple functional layers in the membrane. Vibrational and electrochemical properties of the membrane working electrode are experimentally investigated. In the ASV measurement, the vibration of the piezoelectric diaphragm can enhance the mass transfer rate during the metal deposition step. The sensitivity of sensors under vibration is improved by 4 times, compared with those at static conditions. The detection limit with and without vibration are 0.37 and 1.66 μg/L respectively at a deposition time of 5 min. In addition, the experimental results in this study also indicate the stripping peak current is influenced by the vibrating velocity and mode shape of the piezoelectric diaphragm. The vibrating membrane electrode presented in this study can be potentially used to different types of electrochemical sensing applications limited by the mass transfer rate of the analyte.