β–Cyclodextrin carbon nanotube-enhanced sensor for ciprofloxacin detection

A simple and expedite electrochemical methodology was developed for the determination of ciprofloxacin, based on a glassy carbon (GC) electrode modified by a combination of multi-walled carbon nanotubes (MWCNT) with β-cyclodextrin (β-CD) incorporated in a polyaniline film. The combined use of β-CD and MWCNT in the electrochemical sensor leads to a significant signal improvement. The β-CD/MWCNT modified GC electrode exhibited efficient electrocatalytic behavior in the oxidation of ciprofloxacin with relatively high sensitivity, stability and lifetime. Molecular modeling studies showed that ciprofloxacin binds preferably to β-CD rather than to CNT edges, leading to an improved sensitivity of the sensor. Under optimized conditions, a linear calibration curve was obtained for ciprofloxacin in the concentration range 10-80 µM with a detection limit of 50 nM. The analytical performance of this sensor was evaluated for the detection of ciprofloxacin in a wastewater treatment plant effluent.