Abstract
Heavy metal contamination in aquatic environments poses severe threats to ecological safety and human health due to the acute toxicity and bioaccumulation of lead (Pb(II)) and cadmium (Cd(II)) ions. In this study, we report the development of a highly sensitive and selective electrochemical sensor based on a screen-printed carbon electrode modified with a novel imine-linked covalent organic framework (COF-TAPB-DMTP) for the simultaneous determination of Pb(II) and Cd(II) in environmental water samples. The synthesized COF exhibited a high surface area, ordered porous channels, and rich nitrogen donor sites that facilitated efficient preconcentration of target metal ions through coordination interactions. Under optimized square wave anodic stripping voltammetry (SWASV) conditions, the COF-modified electrode demonstrated wide linear response ranges from 0.5 to 100 µg/L for both Pb(II) and Cd(II), with remarkably low detection limits of 0.12 µg/L for Pb(II) and 0.15 µg/L for Cd(II) (S/N = 3). Furthermore, the sensor displayed excellent anti-interference capability against common co-existing inorganic cations, satisfactory repeatability, and long-term operational stability. The practical utility of the modified electrode was successfully validated by analyzing real tap and river water samples, achieving spike recoveries between 95.2% and 103.8%. This work highlights the potential of tailored COF architectures for robust, portable point-of-need environmental monitoring.
