Determinação simultânea de paracetamol e levofloxacina usando eletrodo de carbono vítreo modificado com carbon black, nanopartículas de prata e PEDOT:PSS

The simultaneous determination of paracetamol (PAR) and levofloxacin (LEV) using a glassy carbon electrode modified with silver nanoparticles (AgNPs), carbon black (CB) and PEDOT:PSS is proposed. The modification of the electrode surface was performed by drop casting dispersion, and morphological characterization of the AgNPs-CB-PEDOT:PSS film was performed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).The electrochemical behaviours of PAR and LEV were evaluated by cyclic voltammetry in the potential range from 0 to 1.2 V, at a scan rate of 0.05 V s-1 . Two oxidation peaks were observed during the anodic potential scanning, at potentials of 0.45 V (PAR) and 1.0 V (LEV). Compared to the bare GCE, the anodic peak currents (ipa) obtained using the AgNPs-CBPEDOT:PSS/GCE sensor were higher by factors of 5.7 (PAR) and 12 (LEV). Under the optimized conditions, square wave voltammetry (SWV) provided linear concentration ranges of from 6.2 × 10−7 to 7.1 × 10−7 mol L−1 (PAR) and from 6.7 × 10−7 to 1.2 × 10−5 mol L−1 (LEV), with detection limits of 1.2 × 10−8 and 1.4 × 10−8 mol L−1 for PAR and LEV, respectively. The AgNPs-CB-PEDOT:PSS/GCE sensor showed good repeatability and no interference in the electrochemical determination of PAR and LEV in presence of concomitants usually found in biological samples. The proposed method was successfully applied using synthetic urine and serum samples, with recoveries of spikes close to 100%.