Chemical Wet Oxidation of Carbon Nanotubes for Electrochemical Determination of Methyl Parathion
Michelle C. Oliveira, Fábio R. Caetano, Maurício A.P. Papi, Emily Y. Watanabe, Luiz H. Marcolino‐Júnior, Márcio F. Bergamini
Abstract
Abstract Surface properties of carbon nanotubes in electrochemical sensors can be dramatically altered depending on chemical groups and structural defects present on the surface. The effect of oxidation on structural integrity of multiwalled carbon nanotubes through acidic (nitric/sulfuric acids) and basic (sodium hydroxide) agents has been studied. Chemical modifications of carbon nanotubes structures were evaluated by Raman, Fourier transform infrared spectroscopy and transmission electronic microscopy. Furthermore, these materials were used to construct sensors for electrochemical determination of pesticide methyl parathion (MP). Under optimized conditions, a calibration curve was obtained for MP determination employing a glassy carbon electrode modified with acidic treated and basic treated carbon nanotubes which showed a linear response ranging from 1.0 × 10–7 to 3.4 × 10–5 M with limits of detection of 3.3 × 10–8 and 3.5 ×10–8 M, respectively. Analytical performance of the electrodes showed similar voltammetric behavior providing good sensitivity for the determination of methyl parathion.