▎ 摘　　要

In this study, we investigated the effects of electrochemical treatment based on cyclic voltammetry (100 cycles with a scan rate of 1 V s(-1)) on pencil graphite electrode (PGE), using different supporting electrolytes compositions (NaOH, HNO3, and KCl all in 0.1 mol L-1). Electrochemically treated electrodes (ePGE) were properly characterized by scanning electron microscopy, Raman spectroscopy, and X-Ray powder diffraction revealing that the proposed strategy provided an efficient exfoliation of graphene sheets on the electrode surface. Additionally, the ePGE showed a 43-fold increase in the electroanalytical response to ciprofloxacin (CIP) when compared to the untreated electrode. The sensor showed excellent analytical performance with a low detection limit (0.35 mu mol L-1), wide working linear range (from 5 to 100 mu mol L-1), and adequate precision (RSD <3.5%). In addition, the sensor provided adequate selectivity about other classes of antibiotics, and when applied to spiked samples, recovery values between 80 and 104% were obtained, which demonstrated satisfactory accuracy, as well as the absence of matrix effect. Thus, the electrochemical treatment provided a simple, fast, and affordable protocol to improve the electrochemical properties of PGE, making it a powerful tool for the investigation of other carbon-based substrates. [GRAPHICS]