The application of carbon nanomaterials as electrode surface modifiers for the voltammetric sensing of nitroxinil – A comparative study

Abstract

This research paper reports on preparation of glassy carbon electrodes (GCE) modified with different carbon nanomaterials, such as single–walled carbon nanotubes (SWCNTs), multi–walled carbon nanotubes (MWCNTs), graphene functionalized using carboxylic groups (fG), and carbon nanohorns (CNHs). Topographical and electrochemical characterization of fabricated electrochemical sensors was performed by atomic force microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. Besides, their application for the determination of veterinary drug nitroxinil (Ntx) was verified. The voltammetric experiments were carried out using square wave voltammetry (SWV) with optimized parameters in Britton–Robinson buffer, pH2.0, which was chosen as the most suitable medium for Ntx determination. The calibration curves for Ntx were constructed employing SWCNTs–GCE, MWCNTs–GCE, fG–GCE, and CNHs–GCE, and limits of quantification (LOQ) and detection (LOD) were assessed. The results showed that all tested modified electrodes can be applied for electroanalysis of Ntx, however, the highest sensitivity and satisfactory LOD of 0.16μmolL−1 and LOQ of 0.53μmolL−1 were obtained for MWCNTs–GCE. For that reason, MWCNTs–GCE was subsequently applied for quantitative analysis of Ntx in milk samples with results proving high repeatability and recoveries.