Nanoarchitectonics of polyaniline-poly(vinyl pyrrolidone)-graphene composite for the electrochemical sensing of ciprofloxacin and uric acid

Background: Ciprofloxacin (Cif) is a fluoroquinolone-based antibiotic that is prescribed for patients infected by gram-positive and gram-negative aerobic pathogens. Owing to its medical applications, target-specific determination of Cif in urine samples is challenging due to the presence of uric acid (UA) as an interference. Methods: Polyaniline-poly(vinylpyrrolidone)-graphene (GPA-PVPy) composite is reported as an electrode material for sensing Cif in the presence of UA. Graphite-polyaniline (GPA) was prepared by oxidative polymerization of aniline at 0–5 °C over 12 h. Subsequently, GPA was used to polymerize vinyl pyrrolidone (VPy) by a free radical polymerization composite in a sonication bath at 70 °C for 6 h. Composites (GPA and GPA-PVPy) are characterized using field-emission scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. GPA and GPA-PVPy composites were coated on a glassy carbon (GC) electrode and investigated by cyclic voltammetry to verify their sensitivity towards Cif in the presence of UA as a major interference. Electrochemical impedance spectroscopy was used to estimate the electron transfer rate of composite electrodes. Significant Findings: Using GPA-PVPy/GC electrode, similar concentrations of UA and Cif (10 – 310 μM) were simultaneously detected in a human urine sample with excellent sensitivity (0.007 μAμM^-1 (UA) and 0.0048 μAμM^-1 (Cif)) and low limit of detection (4.37 μM (UA) and 9.0 μM (Cif)), respectively showing its applicability in medical analysis.