Construction of an Electrochemical Sensor Based on UiO-66-NH2@Polyaniline Composite for Lead Ion Detection
An electrochemical sensor for lead ion (Pb2+) detection was developed based on a metal-organic framework (UiO-66-NH2) and conductive polymer polyaniline (PANI) composite. The UiO-66-NH2 was synthesized via hydrothermal method, and the UiO-66-NH2@PANI composite was prepared by in-situ polymerization. The composite was drop-coated onto a glassy carbon electrode (GCE) to fabricate the sensor. Material characterization was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). Electrochemical performance was evaluated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Key parameters including loading amount, enrichment time, and pH were optimized. Under optimal conditions, the sensor exhibited a linear response to Pb2+ in the concentration range of 10–200 μg·L−1 with a correlation coefficient (R2) of 0.9960, and a limit of detection (LOD) of 9.8 μg·L−1. The sensor demonstrated good anti-interference, repeatability, and stability. Practical applicability was assessed by spiked recovery tests in Yellow River water and tap water, yielding recovery rates of 94.1%–100.8% with relative standard deviations (RSD) ≤3.84%. Comparative analysis with inductively coupled plasma mass spectrometry (ICP-MS) showed comparable accuracy, confirming the sensor's potential for reliable Pb2+ monitoring in environmental samples.