Screen-printed electrodes incorporated in a flow system for the decentralized monitoring of lead, cadmium and copper in natural and wastewater samples

Mercury-based screen-printed electrodes (SPE) combined with square-wave anodic stripping voltammetry (SWASV) techniques for the analysis of copper, cadmium, lead, and zinc in different water samples have been applied. The detection system has been implemented in a flow cell and different experimental conditions have been tested in view of its application for in-situ monitoring. In particular, an acetate buffer together with a low chloride concentration (0.025 M NaCl) provided best performance and reproducible results. Additionally, the flow system was validated for the first time in terms of limits of detection, linearity, repeatability and recovery. Limits of detection of 2.8 µg L−1, 4.1 µg L−1, and 7.5 µg L−1 for cadmium, lead and copper respectively and repeatabilities lower than 10% (as RSD) were found. Good recoveries have been obtained for the three cations and in particular for copper, even in the presence of zinc. Finally, the method has shown its efficiency for the rapid screening of lead, cadmiu...