Highly selective electrochemical detection of ciprofloxacin using reduced graphene oxide/poly(phenol red) modified glassy carbon electrode

In this study, a novel sensor for highly selective and rapid detection of ciprofloxacin is fabricated. A facile strategy was employed to fabricate the electrode by electro-polymerization of phenol red (PPR) followed by drop-casting of reduced graphene oxide (rGO). Under optimized experimental conditions, the developed electrode shows, two linear ranges 0.002-0.05 mu M and 0.05-400 mu M, and the sensitivities equal to 516.41 mu A mu M-1 cm(-2) and 0.239 mu A mu M-1 cm(-2), respectively for ciprofloxacin detection. The rGO/PPR/GCE electrode enhanced sensitivity and low detection limit (LOD) (2 nM) of ciprofloxacin due to selective adsorption, which is accomplished by a combination of electrostatic attraction at SO3- sites in the PPR film, and the formation of charge assisted hydrogen bonding between ciprofloxacin and rGO surface functional groups. The novel nanocomposite was characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electronmicroscopy (FE-SEM), cyclic voltammetry (CV) and electrical impedance spectroscopy (EIS). Differential pulse voltammetry (DPV) was used to study the response of ciprofloxacin towards the modified electrode. The composite modified electrode displayed good electro-catalytic activity towards the oxidation of ciprofloxacin at pH 5.5 and exhibited high sensitivity and specificity towards ciprofloxacin. The practical applicability was tested in the spiked animal serum sample. The recovery of analytes in spiked samples was 97 +/- 6% over the range 0.002-400 mu ML-1. It shows that the developed electrode can be used as a potential tool for a rapid, simple, and sensitive detection of ciprofloxacin in the serum sample.