A simple and expedite electrochemical methodology was developed for the determination of ciprofloxacin, based on a glassy carbon (GC) electrode modified by a composite of magnetic multi- walled carbon nanotubes (MMWCNTS) with Polyethyleneimine (PEI) [1,2]. The combined use of PEI and MMWCNTS in the electrochemical sensor leads to a significant signal improvement. The PEI/MMWCNT modified GC electrode exhibited efficient electrocatalytic behavior in the oxidation of ciprofloxacin with relatively high sensitivity, stability and lifetime [3]. The characterization of the nanocomposite was carried out by scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The performance of the GC electrode modified with PEI@MMWCNTS was investigated using cyclic voltammetry and differential pulse voltammetry to detect ciprofloxacin selectively. Also, we established the electrochemical behavior and the oxidation mechanism of ciprofloxacin by using CV as technique. Furthermore, kinetic studies were done with the aim of calculate the number of transferred electrons in the entire process and to know if it is controlled by adsorption or diffusion. Under optimized conditions, a linear calibration curve was obtained for ciprofloxacin in the concentration range 0.04 70 µM with a detection limit of 0.001 µM. Furthermore, the method was applied for the determination ciprofloxacin in biological fluids such as human serum samples with acceptable recoveries and minimal matrix effect. A comparison of figures of merit between the developed method and other previously developed methods showed that a powerful alternative method for the determination of ciprofloxacin in biological samples has been developed.
