Determination of Gasoline Adulteration by Principal Components Analysis-Linear Discriminant Analysis Applied to FTIR Spectra

Abstract

Brazilian automotive gasoline has been the target of constant adulterations in an attempt to raise profit margins as a result of the market flexibility and the ensuing increased competition. Gasoline adulteration with solvents is common because solvents present lower taxation in comparison to gasoline. In the face of this, the importance of developing low-cost analytical techniques such as spectroscopy to certify the quality and authenticity of fuels used in Brazil is conspicuous. This work used IR spectroscopy and multivariate techniques (principal components analysis-linear discriminant analysis, PCA-LDA) to determine gasoline adulteration by solvent and to identify the solvent added. The results show that FTIR associated with PCA-LDA is a powerful technique in the quality control of automotive gasoline. The method sensitivity was 8% v/v with 96% efficiency in the classification of adulterated and unadulterated gasoline and 93% efficiency in the identification of the type of solvent added.