AuNP-Modified Electrochemical Heavy Metal Ion Sensors Based on an AAO Hard Mask

Heavy metals are widely found in various substances in human life and industrial production, causing serious harm to humans and the environment. In this paper, we proposed a gold nanoparticle (AuNP)-modified sensor for heavy metal detection (Pb²⁺, Cu²⁺). With a simple and controllable AuNP modification method based on an anodic aluminum oxide (AAO) hard mask, the detection performance of the electrochemical sensors was improved. Meanwhile, the pH and enrichment time are optimized to obtain optimal detection conditions for as-fabricated sensors. Compared with the traditional methods for the detection of heavy metal ions, as-fabricated sensors have a wider linear range (Cu²⁺: 0.5-200 μg/L; Pb²⁺: 20-200 μg/L), lower detection limit (10^-6 g/L), and smaller size (5.5 cm × 2.5 cm). Meanwhile by designing an adaptive hardware detection circuit, these sensors demonstrate reusable and portable performance with lower cost. This work will play an increasingly important role in the fields of environmental monitoring, biomedicine, and food safety.