Study of premium and regular gasolines marketed in brazil through the eretic-nmr method and chemometrics

STUDY OF PREMIUM AND REGULAR GASOLINES MARKETED IN BRAZIL THROUGH THE ERETIC-NMR METHOD AND CHEMOMETRICS. Gasoline is a complex mixture of hydrocarbons whose detailed study of its chemical profiles is a challenging task. This type of product of great commercial importance has its quality measured in Brazil from classical physical chemical tests. Although robust, physical-chemical analyses generally require large amounts of assays, solvents, and samples, in addition to not being indicated for the detection of small compositional changes. In this work, NMR and chemometrics were used in the quantitative study of different samples of gasoline with varying ratings of octane and ethanol contents. The results demonstrated the usefulness of NMR spectroscopy both to characterize as well as to distinguish the chemical profiles of regular and premium gasoline. With the application of the ERETIC, the chemical profiles mentioned were quantitatively differentiated and the proportions between hydrocarbons were determined for both types of gasoline. The application of the ERETIC was also successful in the quantitative determination of ethanol contents in regular and premium gasoline. The aforementioned method, which dispenses with the use of quantification standards inserted directly into the sample of interest, was unequivocal in accounting for the volume of ethanol, in addition to showing excellent agreement with the method currently adopted by the Brazilian government.