Ferrocene-functionalized NH2-UiO-66/MoO3 ratiometric electrochemical sensing platform for efficient monitoring of levofloxacin

As a third-generation fluoroquinolone antibiotic, levofloxacin (LEV) residue in biological and environmental samples has aroused widespread public concern. In this work, NH 2 -UiO-66 was in-situ synthesized via a solvothermal route on MoO 3 surface. Subsequent covalent modification with ferrocene (Fc) afforded a ratiometric electrochemical sensor denoted as Fc-NH 2 -UiO-66/MoO 3 /GCE for LEV quantification. The anchored Fc units not only construct an internal self-calibration system with stable reference signal to greatly improve detection reliability, but also boost the electrical conductivity of the composite electrode. The as-fabricated sensor exhibits favorable analytical performance toward LEV, featuring a wide linear range of 0.6 µM-600 µM and a low limit of detection of 0.032 µM, together with stable anti-interference capability. Moreover, the developed electrode was successfully employed to determine LEV in practical specimens including serum, urine and commercial LEV eye drops. This reliable and sensitive analytical strategy exhibits promising prospects for clinical diagnosis and pharmaceutical analysis. Graphical abstract