Simple and disposable device based on gold nanoparticles modified screen-printed carbon electrode for detection of ciprofloxacin

This study describes the development and characterization of an electrochemical sensor based on gold nanoparticles (AuNPs) immobilized on a screen-printed carbon electrode (SPCE) supported by polyethylene terephthalate (PET) for ciprofloxacin (CPX) detection. The SPCE-AuNPs sensor was fabricated using optimized carbonaceous material-based inks for the working and counter electrodes, while silver/silver chloride ink was employed for the quasi-reference electrode. Electrochemical characterization revealed a significant 223% increase in CPX oxidation current intensity compared to the unmodified SPCE electrode. Electrochemical impedance spectroscopy (EIS) confirmed this improvement, showing a decrease in charge transfer resistance (Rct) from 0.225 kΩ for SPCE to 0.125 kΩ for SPCE-AuNPs. Under optimized conditions utilizing differential pulse voltammetry (DPV), the sensor exhibited a linear range of 0.4 to 88.0 μmol L⁻¹, a limit of detection of 0.12 μmol L⁻¹, and a limit of quantification of 0.4 μmol L⁻¹. The developed method was applied to determine CPX in water and pharmaceutical formulation samples, achieving excellent recovery values ranging from 96 to 104%.