Simultaneous determination of paracetamol and levofloxacin using a glassy carbon electrode modified with carbon black, silver nanoparticles and PEDOT:PSS film

Abstract

A new voltammetric sensor is proposed for the simultaneous determination of paracetamol (PAR) and levofloxacin (LEV), using a glassy carbon electrode (GCE) modified with silver nanoparticles (AgNPs), carbon black (CB), and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS). The modification of the electrode surface was performed by drop-casting dispersion. Morphological characterization of the AgNPs-CB-PEDOT:PSS film was performed by scanning electron microscopy and transmission electron microscopy. The electrochemical behaviors of PAR and LEV were evaluated by cyclic voltammetry in a potential range from 0 to 1.2V, at a scan rate of 0.05Vs−1. Two oxidation peaks were observed during the anodic potential scanning, at potentials of 0.45 (PAR) and 1.0V (LEV). Compared to the bare GCE, the anodic peak currents (ipa) obtained using the AgNPs-CB-PEDOT:PSS/GCE sensor were higher by factors of 5.7 (PAR) and 12 (LEV). The electrochemical determination by square wave voltammetry provided linear concentration ranges of 6.2×10−7 to 7.1×10−6molL−1 (PAR) and 6.7×10−7 to 1.2×10−5mol L−1 (LEV), with detection limits of 1.2×10−8 and 1.4×10−8molL−1 for PAR and LEV, respectively. The AgNPs-CB-PEDOT:PSS/GCE sensor showed good stability, reproducibility, and repeatability, and no interference in the electrochemical determination of PAR and LEV in the presence of other compounds. The proposed method was successfully applied using synthetic urine and river water samples, with recoveries close to 100%.