An application of a glassy carbon electrode and a glassy carbon electrode modified with multi-walled carbon nanotubes in electroanalytical determination of oxycarboxin

An electrochemical procedure for the quantitative determination of oxycarboxin at a glassy carbon electrode (GCE) and a glassy carbon electrode modified with multi-walled carbon nanotubes (GCE/MWCNTs) based on square wave adsorptive stripping voltammetry (SWAdSV) is presented for the first time. The effect of an amplitude (E (SW)), a frequency (f), a step potential (Delta E (s)), an accumulation potential (E (acc)) and time (t (acc)), and equilibration time (t (eq)) was investigated. The best analytical signal was obtained in the medium of sulfuric acid on both electrodes. Under optimal analytical conditions, the linear ranges of Oxy concentrations 8.0 x 10(-6)-5.0 x 10(-5) mol L-1 with limit of detection of 2.0 x 10(-6) mol L-1 for bare GCE and 6.0 x 10(-6)-9.0 x 10(-5) mol L-1 with limit of detection of 1.1 x 10(-6) mol L-1 for GCE/MWCNTs were obtained. To investigate the utility of the proposed method for the determination of oxycarboxin in real samples, a quantitative determination of Oxy was performed in spiked river water samples. The electrode processes of oxycarboxin oxidation were studied by cyclic voltammetry (CV) at both electrodes. The surface characterization of bare GCE and GCE/MWCNTs was evaluated with an atomic force microscopy (AFM) and a scanning electron microscopy (SEM).