title: Quality assessment of gasoline using comprehensive two-dimensional gas chromatography combined with unfolded partial least squares: A reliable approach for the detection of gasoline adulteration.
abstract: Comprehensive two-dimensional gas chromatography and flame ionization detection combined with unfolded-partial least squares is proposed as a simple, fast and reliable method to assess the quality of gasoline and to detect its potential adulterants. The data for the calibration set are first baseline corrected using a two-dimensional asymmetric least squares algorithm. The number of significant partial least squares components to build the model is determined using the minimum value of root-mean square error of leave-one out cross validation, which was 4. In this regard, blends of gasoline with kerosene, white spirit and paint thinner as frequently used adulterants are used to make calibration samples. Appropriate statistical parameters of regression coefficient of 0.996-0.998, root-mean square error of prediction of 0.005-0.010 and relative error of prediction of 1.54-3.82% for the calibration set show the reliability of the developed method. In addition, the developed method is externally validated with three samples in validation set (with a relative error of prediction below 10.0%). Finally, to test the applicability of the proposed strategy for the analysis of real samples, five real gasoline samples collected from gas stations are used for this purpose and the gasoline proportions were in range of 70-85%. Also, the relative standard deviations were below 8.5% for different samples in the prediction set.
authors.affiliation: Department of Chemistry, Sharif University of Technology, Tehran, Iran.
authors.forename: Hadi
authors.initials: H
authors.lastname: Parastar
authors.affiliation: Department of Chemistry, University of Isfahan, Isfahan, Iran.
authors.forename: Sara
authors.initials: S
authors.lastname: Mostafapour
authors.affiliation: Department of Chemistry, University of Isfahan, Isfahan, Iran.
authors.forename: Gholamhasan
authors.initials: G
authors.lastname: Azimi
keywords: Adulteration; Chemometrics; Gas chromatography; Gasoline; Partial least squares