Study of different types of copper electrodes for anodic stripping voltammetric detection of trace metal ions

Copper electrodes exhibit interesting characteristics for application in electrochemical stripping analysis and represent another alternative to their mercury counterparts. In this work, we studied different types of copper-based electrodes for anodic stripping voltammetric detection of trace metal ions. We investigated copper film (CuFE), and bulk copper electrodes, such as in-situ and ex-situ prepared CuFEs using glassy carbon and screen-printed carbon supporting electrodes, a bulk copper disk and screen-printed copper electrode, and a copper wire as the simplest, inexpensive, and readily available analog. For studying their electroanalytical performances, low concentrations (μg L−1) of Cd(II) and Pb(II) were used as model ions. We examined and optimized several key parameters affecting the preparation and functioning of copper electrodes, such as the composition of the measurement solution, copper concentration for in-situ and ex-situ preparation of CuFE, deposition potential, deposition time, etc. Most of the tested copper electrodes showed favorable stripping voltammetric performances, particularly the CuFE ex-situ prepared on a glassy carbon electrode and the CuFE in-situ prepared on a screen-printed carbon substrate. Notably, a copper wire revealed an excellent electroanalytical operation with a limit of detection of 0.6 μg L−1 for Pb(II) and 1.8 μg L−1 for Cd(II). The practical applicability of a copper electrode was tested by measuring a real tap water sample.