Stable sandwich-type electrochemical lead ions sensor based on bismuth-metal organic framework and Mxene

For electrochemical Pb 2+ detection, high sensitivity and stability are essential owing to the mutagenicity, carcinogenicity, and teratogenicity of aqueous Pb 2+ ions. Herein, a three-dimensional bismuth-containing metal-organic framework (Bi-MOF) was synthesized using a hydrothermal method, followed by post-synthetic functionalization with thiol (-SH) groups. A sandwich-type Bi-MOF-SH/Mx/Bi-MOF-SH/GCE multilayer sensitive electrochemical sensor was then constructed on the surface of the glassy carbon electrode for Pb 2+ detection. Differential pulse anodic stripping voltammetry (DPASV), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were used to evaluate the performance of the sensor. The developed multilayer sensor demonstrated an exceptionally high current response, good sensitivity (0.03–20.0 μg/L), and an ultra-low level of detection of 0.012 μg/L (S/N=3) towards Pb 2+ ions. The as-prepared electrode showed high stability, repeatability, and selectivity among possible interfering ions (Na + , Ca 2+ , Cu 2+ , Zn 2+ , K + , Mg 2+ , Al 3+ , and Cd 2+ ), suggesting potential for use in real-world applications.