Electroanalysis of Cefadroxil Antibiotic at Carbon Nanotube/Gold Nanoparticle Modified Glassy Carbon Electrodes

Abstract The electrochemical characterization and determination of the antibiotic cefadroxil were carried out at multi‐walled carbon nanotube (CNT) and gold nanoparticle (AuNP) modified glassy carbon electrodes (GCE). Oxidation of the phenol moiety of cefadroxil occurred at slightly less‐positive potentials and with a higher current response than at bare GCE. Differential pulse voltammetry and electrochemical impedance spectroscopy showed that the architecture combining CNT and AuNP surface modification is the best in pH 7 buffer solution. Scanning electron microscopy demonstrated good coverage of the AuNPs on the CNTs. The fixed potential amperometric determination of cefadroxil was carried out at +0.74 V vs Ag/AgCl with a limit of detection of 0.22 μM. Analysis of cefadroxil in commercial samples presented high recovery values and the amount of the pharmaceutical in each capsule was in excellent agreement with that measured by UV/Vis spectroscopy.