Ultra‐Sensitive Amperometric Detection of Ciprofloxacin in Environmental and Biological Matrices Using an ITO Modified With Tungsten Trioxide‐Based Nanocomposite

ABSTRACT

Although significant progress has been achieved in the electrochemical sensing of ciprofloxacin (CIP), there remains a critical need for highly sensitive and reliable platforms capable of rapid charge transfer and accurate detection at trace levels in complex environmental and biological matrices. In this work, a tungsten trioxide (WO ₃ )/titanium carbide (TiC)/graphitic carbon nitride (g‐C ₃ N ₄ ) ternary nanocomposite was synthesized via a facile hydrothermal method and structurally characterized by XRD, XPS, FTIR, UV–vis, PL and SEM. UV–vis analysis revealed a reduced band gap for the nanocomposite compared to the individual components, indicating an improved electronic structure and enhanced light absorption. Furthermore, photoluminescence (PL) studies demonstrated a significant reduction in emission intensity, indicating effective charge separation and suppressed electron–hole recombination. Electrochemical investigations demonstrated a significantly enhanced response towards CIP in comparison to the individual components. Cyclic voltammetry (CV) showed a higher oxidation current, while electrochemical impedance spectroscopy (EIS) confirmed a reduced charge transfer resistance, evidencing strong synergistic interactions within the ternary system. This enhanced performance is attributable to the complementary functions of TiC, which improves electrical conductivity, WO ₃ , which provides numerous electroactive sites, and g‐C ₃ N ₄ , which facilitates charge transfer and analyte adsorption. The developed sensor demonstrated a broad linear range from 10 to 200 µM ‘CIP’, an ultra‐low detection limit (LOD) of 0.02 µM and an exceptional sensitivity of 7.97 µA µM ⁻¹ cm ⁻² . Furthermore, the sensor's performance has been demonstrated by the excellent selectivity and satisfactory recoveries in real samples, including river water, tap water and saliva. This demonstrates its practical applicability for environmental monitoring.