Integration of Mesoporous Copper Coordination Polymer in Electrochemical Platform for Detection of Fluoroquinolone Antibiotic in Biological and Food Samples

Antibiotics are indispensable in both human and veterinary medicine. However, their extensive and indiscriminate use has raised serious environmental and public health concerns, particularly regarding the emergence of antibiotic-resistant bacteria. In this context, continuous monitoring of broad-spectrum antibiotics, such as fluoroquinolone class, is essential. This study reports the development of an electrochemical sensor based on a copper-based coordination polymer, [Cu-(C₈H₄O₄)] _<i>n</i> /CPE, for the detection of fluoroquinolone antibiotic (ciprofloxacin, CIP) in synthetic urine and egg samples. [Cu-(C₈H₄O₄)] _<i>n</i> was synthesized via a solvothermal method, employing 1,4-benzenedicarboxylic acid as the organic ligand and copper salt as the metal source. The material was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), thermogravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET) surface area analysis. Electrode modification was optimized by varying the modifier content, pH solution, and electrochemical technique. Optimization using differential pulse voltammetry (DPV) revealed ideal conditions at pH 6.0 with 20% (w/w) [Cu-(C₈H₄O₄)] _<i>n</i> . Under this condition, the sensor exhibited excellent linearity (<i>R</i> ² = 0.992), recoveries ranging from 78 to 108%, and relative standard deviation (RSD) bellow 10% (<i>n</i> = 3). The limits of detection (LOD) and quantification (LOQ) were 0.5 and 1.7 μmol L^-1 in synthetic urine and 3.0 and 10.1 μmol L^-1 in egg sample, respectively. The [Cu-(C₈H₄O₄)] _<i>n</i> /CPE sensor demonstrated high sensitivity and accuracy, highlighting its potential as reliable tool for monitoring CIP residues in food products and biological samples, thereby contributing to food safety and public health.