▎ 摘　　要

In this paper, we compare reduced graphene oxide (RGO) electrode with multi-walled carbon nanotubes (MWCNT) as modifiers for the sensitive detection of levofloxacin. The RGO-based sensor showed higher currents for levofloxacin compared with the MWCNT-modified (4-fold) and unmodified electrodes (20-fold). A thin-layer adsorptive process was verified for the oxidation of levofloxacin on the RGO-modified electrode which explains the higher currents. Differential pulse voltammetry (DPV), square wave voltammetry (SWV), and amperometric detection using flow-injection analysis (FIA-AMP) were evaluated for levofloxacin determination in urine and pharmaceutical samples. Detection limits of 1.45, 6.70, and 1.90 mu mol L-1 and recovery levels of 91, 106, and 103%, respectively were obtained. A relative standard deviation lower than 7.7% indicated proper precision. The FIA-AMP using the RGO-modified electrode presented high analytical frequency (around 100 injections per hour) and thus was selected for the analysis of the samples. Statistically, similar results (95% confidence level) compared with ultra-fast liquid chromatography (UFLC) analysis and recovery level of 96% for the analysis of urine were obtained.