Chronoamperometric Detection of Lead and Copper Ions From Tap Water

We investigated the chronoamperometric, simultaneous detection of lead and copper ions from tap water using carbon electrodes. Monitoring of heavy metal (HM) ions in water is essential due to widespread contamination and the multitude of documented health risks associated with HM ion exposure. Electrochemical sensors are promising candidates for decentralized monitoring, particularly as contamination often occurs within the drinking water supply toward the point of use. We used anodic stripping voltammetry (ASV) to determine the electrochemical performance of the electrode toward the deposition and detection of lead and copper. The need for a slight acidification of the tap water with sulfuric acid to pH 5.1 was demonstrated, which yielded results comparable to the standard electrolyte perchloric acid at pH 1. From the stripping voltammetry results, we derived a four-step chronoamperometric protocol that uniquely combines metal deposition with subsequent stripping and detection at fixed electrode potentials in a cyclic protocol. Distinct, quantitative, and reproducible current responses were obtained for metal detection at the respective stripping potentials. We demonstrated the highly sensitive (100–400 $A\cdot $ mm $^{\mathbf {-{2}}} \cdot $ mM $^{\mathbf {-{1}}}$ ) and selective simultaneous detection of lead and copper in acidified tap water down to the micromolar range and discussed influencing factors for parameter optimization. The usage of disposable, unmodified electrodes, together with chronoamperometric protocols and the single-step acidification by sulfuric acid, outlines a time- and cost-effective approach in tap water monitoring. Such methods for the rapid and continuous detection of lead and copper are crucial steps in facilitating the widespread and efficient monitoring of water pollution.