MnO2 nanoparticles enhance the activity of the Zr-MOF matrix electrochemical sensor for efficiently identifying ultra-trace tetracycline residues in food

A novel nanobiosensor was constructed by in situ locating nanometer MnO 2 particles with controllable size and morphology in a Zr-MOF substrate to serve as an electrochemical probe. The synergistic effect of the two components, Zr-MOFs with high specific surface area and compatibility as a carrier for MnO 2 , resulted in improved electrochemical activity and excellent electrochemical identification performance for the MnO 2 @Zr-MOF/GCE biosensor. Under optimized experimental conditions and using CV and DPV technology, the biosensor showed a wide linear detection range (2–200 μM), a low detection limit (2.577 × 10 −8  M), a recovery range (106.26–115.01%), and maximum relative standard deviation (5.155) for tetracycline (TC) identification. The recognition mechanism of the sensor was investigated adopting Laviron adsorption theory. The applicability of the sensor was verified through practical measurements. Overall, the MnO 2 @Zr-MOF/GCE sensor possesses the advantages of fast analysis speed, high sensitivity, high selectivity, and simple operation, making it suitable for detecting trace amounts of TC in food. Graphical abstract