SENSORS AND ACTUATORS B-CHEMICAL, cilt.320, 2020 (SCI-Expanded)
An electrochemical nanosensor for monitoring zafirlukast (ZAF) concentration in biological fluids was developed by the modification of the glassy carbon electrode (GCE) surface via layer-by-layer approach. The GCE surface was first modified with amine-functionalized multi-walled carbon nanotubes (NH2-fMWCNTs), and then sodium dodecylsulfate doped over-oxidized polypyrrole film (SDS-ooPPy) was electrosynthesized on the NH2-fMWCNTs/GCE. The morphology and characterization of prepared nanosensor were done by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The developed sensor has an excellent electrocatalytic activity towards the oxidation of ZAF, resulting in enhancing the electrochemical response, due to the synergistic effect between NH2-fMWCNTs and SDS-ooPPy and more negative charge density of ooPpy on a 1D structure of NH2-fMWCNTs. The parameters affecting the electrochemical behavior of ZAF including pH, the amount of NH2-fMWCNTs, the concentration of SDS and pyrrole (Py) monomer, and the number of cycles required in the electropolymerization step for the modification of electrode were optimized. The redox mechanism pathway for the electro-oxidation of ZAF and the thermodynamic study was performed by CV. The calibration graph of ZAF determination by square wave voltammetry (SWV) under the optimized condition using SDS-ooPPy/NH2-fMWCNTs/GCE provided a linear range of 1.0 x 10(-7) M to 1.0 x 10(-5) M. The sensitivity of 4442 mu A mM(-1) cm(-2) and a LOD of 20.0 nM (S/N = 3) were obtained. Finally, the proposed nanosensor was used successfully for monitoring of ZAF in biological fluids with acceptable recovery data.