Electrochemical method for point-of-care determination of ciprofloxacin using boron-doped diamond electrode

This paper presents an electrochemical behavior study and quantification of fluoroquinolone antibiotic ciprofloxacin using boron-doped diamond electrode. Ciprofloxacin provides a diffusion-driven electrode reaction with an irreversible and poorly defined peak at +1.6 V vs. Ag/AgCl electrode in the presence of Britton-Robinson buffer solution pH 4. Applying differential pulse voltammetry (modulation amplitude of 60 mV, modulation time of 50 ms), the calibration curve with high linearity (R² = 0.997) was obtained within the concentration range of (0.74 – 20.0) × 10⁻⁶ mol L⁻¹ with the detection limit of 6.0 × 10⁻⁷ mol L⁻¹ and repeatability expressed by relative standard deviation of 2.7 % (for 20 measurements). Interference study was performed to explore the selectivity of the elaborated procedure. By analysis of pharmaceutical dosages and model human urine samples, the ciprofloxacin content with the recovery values ranging from 88.4 to 121.2 % were determined. The developed approach using point-of-care electrochemical sensor based on boron-doped diamond material could represent inexpensive analytical alternative to separation methods and could be beneficial in analysis of biological samples and in the quality control in pharmaceutical industry.