Determination of Ochratoxin at Nanocomposite Modified Glassy Carbon Electrode Combine with FFT Coulometric Admittance Voltammetry and Flow Injection Analysis

摘要

In this work, a new electrochemical techniguetechnique based on combination of FFT CoulometricAdmittance Voltammetry (FFTCAV) technique and a nanocomposite electrode was developed for thedetermination of Ochratoxin A in a flow- injection system. The sensor was designed by deposition ofgold nanoparticles on reduced graphene nanosheets mixed with carbon multiwall nanotube and ionicliquid (1-ethyl-3-methyl-imidazolium ethylsulphateas) casted on a glassy carbon electrode. Also, inthis technique the sensor response calculated in form of charge changes under the peak by integratingadmittance in selected potential range, after subtracting the background admittance. As results,application of the nanocomposite as a modifier can catalyze electron transfer, which causes amplifyingthe response. Besides, iIt was found the electrode response was proportional to concentrations of-12 Ochratoxin A in range from 0.1 to 200 nM, with a detection limit of 3.710 M. The nanocompositeelectrode showed good reproducibility, a long-term of usage stability for 90 days. The characterizationof the sensor surface was studied by scanning electron microscopy and electrochemical impedancespectroscopy methods.