An Ultra-Sensitive Electrochemical Sensing Platform Based on a Novel Ternary Heterostructured Ag-TiO2@Zr-TCBPE Nanocomposite for Ciprofloxacin Detection in Food

To address ciprofloxacin (CIP) contamination in animal-derived foods, an ultrasensitive electrochemical sensing platform based on a novel ternary heterostructure (Ag-TiO₂@Zr-TCBPE) was developed through interfacial engineering. The heterointerface was constructed by anchoring a metal–metal oxide electrocatalyst (Ag-TiO₂) onto a conductive metal–organic framework (Zr-TCBPE) with a 3D porous hexagonal prismatic structure and high conductivity. This work demonstrates for the first time that the large-scale conjugated architecture of Zr-TCBPE nanotubes enhances CIP enrichment, while the Ag-TiO₂/Zr-TCBPE heterointerface optimizes electron transport pathways and synergistically promotes CIP oxidation via interfacial electric field-driven effects. Under acidic conditions (pH 5.0), the Ag-TiO₂@Zr-TCBPE/GCE sensor exhibited optimal performance: a linear range spanning five orders of magnitude (2.5 nmol·L⁻¹ to 150 μmol·L⁻¹), a limit of detection (LOD) of 1.6 nmol·L⁻¹, surpassing most reported CIP sensors. The sensor also showed high anti-interference capability (97.1–107% signal retention), long-term stability (> 96.4% signal retention after 15 days), and satisfactory recovery rates (91.6–103%) in complex matrices (milk, eggs, and river water). This study provides fundamental insights into TCBPE-MOF heterointerface engineering and establishes a robust analytical platform for detecting trace antimicrobials in food and environmental samples.