Construction of an Electrochemical Sensor Based on UiO-66-NH2@Polyaniline Composite for Lead Ion Detection

• • The UiO-66-NH2@PANI/GCE sensor achieved a linear detection range of 10–200 μg·L−1 for Pb2+ with R2 = 0.9960 and a limit of detection (LOD) of 9.8 μg·L−1, enabling sensitive quantification at trace levels relevant to water quality monitoring. • • Spiked recovery rates in real water samples (Yellow River and tap water) ranged from 94.1% to 100.8% with RSD ≤ 3.84%, demonstrating accuracy comparable to ICP-MS (recoveries 94.35%–99.26%, RSD 0.10%–2.09%) while offering a more cost-effective and field-deployable alternative. • • The sensor exhibited excellent repeatability and reproducibility, with an RSD of 3.44% for reproducibility, indicating consistent fabrication and performance essential for routine analytical applications. • • The composite material combines the high surface area and functional groups of UiO-66-NH2 with the conductivity of polyaniline, enhancing electron transfer and Pb2+ preconcentration, which is critical for achieving low detection limits in heavy metal sensing.