Ultrasensitive electrochemical detection of metronidazole using binder-free zinc-4,4'-oxybis(benzoic acid) MOF/GCE in real samples.

A novel electrochemical sensor is constructed by modifying the glassy carbon electrode (GCE) using a binder-free metal-organic framework of V-shaped linker 4,4'oxybis(benzoic acid) (OBA) and various transition metals (M-Zn, Mn, or Ni). The hydrothermally synthesized M-OBA MOFs demonstrated superior electron transfer ability and enhanced electro-reduction behaviour, making it highly effective for metronidazole (MTZ) detection. The optimized sensor demonstrated a linear response from 0.04 to 122.18 µM, a low detection limit (LOD) of 0.009 µM, and high sensitivity (0.48 µA µM cm) using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The sensor also exhibited excellent selectivity in the presence of various ions, organic compounds, and other antibiotics. The Zn-OBA MOF sensor proves practical applicability for detecting MTZ in milk, honey, tap water, and MTZ tablets.