Voltammetric determination of ethyl acetate in ethanol fuel using a Fe3+/Nafion®-coated glassy carbon electrode

AbstractA voltammetric method for the determination of ethyl acetate in ethanol fuel using a Fe3+/Nafion®-coated glassy carbon electrode (GCE) is proposed. The ethyl acetate present in the ethanol fuel was previously converted to acetohydroxamic acid via pretreatment with hydroxylamine chloride. The acetohydroxamic acid promptly reacted with the iron (III) present in the film, producing iron (III) acetohydroxamate, which presents a well-defined voltammetric peak current at −0.02V. Optimization of the voltammetric parameters for the cyclic, linear sweep, square wave, and differential pulse modalities was carried out for this chemically-modified electrode. Square wave voltammetry afforded the best response for acetohydroxamic acid detection. The analytical curve for this species was linear from 9 to 100μmolL−1 according to the following equation: ip (μA)=0.27+2.55Cacetohydroxamic acid (μmolL−1), with linear correlation coefficient equal to 0.993. The technique presented limit of detection equal to 5.3μmolL−1 and quantification limit of 17.6μmolL−1. The proposed method was compared to the official method of ethyl acetate analysis (Gas Chromatography), and a satisfactory correlation was found between these techniques