title: Screening analysis to detect adulteration in diesel/biodiesel blends using near infrared spectrometry and multivariate classification.
abstract: This paper proposes an analytical method to detect adulteration of diesel/biodiesel blends based on near infrared (NIR) spectrometry and supervised pattern recognition methods. For this purpose, partial least squares discriminant analysis (PLS-DA) and linear discriminant analysis (LDA) coupled with the successive projections algorithm (SPA) have been employed to build screening models using three different optical paths and the following spectra ranges: 1.0mm (8814-3799 cm(-1)), 10mm (11,329-5944 cm(-1) and 5531-4490 cm(-1)) and 20mm (11,688-5952 cm(-1) and 5381-4679 cm(-1)). The method is validated in a case study involving the classification of 140 diesel/biodiesel blend samples, which were divided into four different classes, namely: diesel free of biodiesel and raw vegetal oil (D), blends containing diesel, biodiesel and raw oils (OBD), blends of diesel and raw oils (OD), and blends containing a fraction of 5% (v/v) of biodiesel in diesel (B5). LDA-SPA models were found to be the best method to classify the spectral data obtained with optical paths of 1.0 and 20mm. Otherwise, PLS-DA shows the best results for classification of 10mm cell data, which achieved a correct prediction rate of 100% in the test set.
authors.affiliation: Universidade Federal da Paraíba, Departamento de Química, João Pessoa, PB, Brazil. marciocoelho@quimica.ufpb.br
authors.forename: Márcio José Coelho
authors.initials: MJ
authors.lastname: Pontes
authors.forename: Claudete Fernandes
authors.initials: CF
authors.lastname: Pereira
authors.forename: Maria Fernanda
authors.initials: MF
authors.lastname: Pimentel
authors.forename: Fernanda Vera Cruz
authors.initials: FV
authors.lastname: Vasconcelos
authors.forename: Alinne Girlaine Brito
authors.initials: AG
authors.lastname: Silva
mesh_terms: D056804:Biofuels / Q000032:analysis*; D016002:Discriminant Analysis; D005742:Gasoline / Q000032:analysis*; D016018:Least-Squares Analysis; D015999:Multivariate Analysis; D010363:Pattern Recognition, Automated; D010938:Plant Oils / Q000737:chemistry; D025341:Principal Component Analysis; D013055:Spectrophotometry, Infrared / Q000379:methods*
chemical_list: D056804:Biofuels; D005742:Gasoline; D010938:Plant Oils