preparation of a modified electrode for the determination of levofloxacin

In this study, modification of glassy carbon electrode with electrochemically reduced graphene oxide (ERGO) and acid treated multi-walled carbon nanotubes (A-MWCNT) was investigated for the voltammetric determination of LEV in body fluids and pharmaceutical products. Different combinations of GO, ERGO, MWCNT and A-MWCNT were searched and the best results obtained with GC/ERGO/A-MWCNT electrode. The prepared modified electrode showed electrocatalytic acitivity towards LEV oxidation by increasing oxidation peak currents 293 times. Characterizations of the modified electrode was performed with cyclic voltammetry, electrochemical impedance spectroscopy and raman measurements. The highest oxidation peak current was observed at pH value of 2.0. The oxidation peak currents of LEV increased linearly with the concentration of LEV in the range of 0.01 mM and 10 mM. The detection limit of the prepared sensor was determined as 0.0063 mM. After three weeks’ storage, the prepared electrode showed high stability by preserving 93% of its original activity towards 1.0 mM LEV. The prepared electrode successfully discriminates the voltammetric response of LEV from that of other fluoroquinolone antibiotics (enoxacin, norfloxacin, ciprofloxacin). Finally, the performance of the prepared electrode was tested in the determination of LEV in human blood serum, urine and pharmaceutical samples.