Abstract

For the first time, simultaneous voltammetric determination of two kinds of the first-line categorized anti-tuberculosis drugs including isoniazid (INZ) and ethambutol (EBL) was reported at a highly sensitive electrochemical sensor. The proposed sensor was successfully prepared based on an electroactive poly-melamine film and electrodeposited gold nanoparticles (P-Mel-Au-nano)-modified pre-anodized glassy carbon electrode (GCE(*)). The morphological and electrochemical characteristics of the sensing surface (P-Mel-Au-nano/GCE(*)) was well-characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The P-Mel-Au-nano/GCE(*) exhibited strongly catalytic activity toward the oxidation of INZ (0.39 V potential shift) and EBL (0.29 V potential shift) in comparison with P-Mel/GCE(*) and bare GCE. Differential pulse voltammograms of INZ and EBL depicted the linear responses with their concentrations at the ranges of 0.3 to 170.0 mu M and 0.5 to 150.0 mu M, respectively. The detection limits for INZ and EBL were sequentially estimated as 0.08 and 0.21 mu M. Furthermore, the developed electrochemical sensor was successfully implemented for the determination of INZ and EBL in real samples using standard addition method. This fabricated sensor showed to be promising for INZ and EBL detection with many desirable features including high-sensitivity, low detection limit, decrease in over-voltage, reproducible responses, and acceptable anti-interferences ability.