title: Calibration sets selection strategy for the construction of robust PLS models for prediction of biodiesel/diesel blends physico-chemical properties using NIR spectroscopy.
abstract: Even when the feasibility of using near infrared (NIR) spectroscopy combined with partial least squares (PLS) regression for prediction of physico-chemical properties of biodiesel/diesel blends has been widely demonstrated, inclusion in the calibration sets of the whole variability of diesel samples from diverse production origins still remains as an important challenge when constructing the models. This work presents a useful strategy for the systematic selection of calibration sets of samples of biodiesel/diesel blends from diverse origins, based on a binary code, principal components analysis (PCA) and the Kennard-Stones algorithm. Results show that using this methodology the models can keep their robustness over time. PLS calculations have been done using a specialized chemometric software as well as the software of the NIR instrument installed in plant, and both produced RMSEP under reproducibility values of the reference methods. The models have been proved for on-line simultaneous determination of seven properties: density, cetane index, fatty acid methyl esters (FAME) content, cloud point, boiling point at 95% of recovery, flash point and sulphur.
authors.affiliation: Department of Chemistry, Faculty of Sciences, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
authors.forename: Anna
authors.initials: A
authors.lastname: Palou
authors.affiliation: Department of Chemistry, Faculty of Sciences, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
authors.forename: Aira
authors.initials: A
authors.lastname: Miró
authors.affiliation: Department of Chemistry, Faculty of Sciences, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Blanco
authors.affiliation: Centro de Investigación CEPSA, Avda. Punto Com 1, 28805 Alcalá de Henares, Madrid, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Larraz
authors.affiliation: Refinería Gibraltar - San Roque CEPSA, Puente Mayorga, s/n, 11360 San Roque, Cádiz, Spain.
authors.forename: José Francisco
authors.initials: JF
authors.lastname: Gómez
authors.affiliation: CEPSA, Campo de las Naciones, Avda. del Partenón 12, 28042 Madrid, Spain.
authors.forename: Teresa
authors.initials: T
authors.lastname: Martínez
authors.affiliation: CEPSA, Campo de las Naciones, Avda. del Partenón 12, 28042 Madrid, Spain.
authors.forename: Josep Maria
authors.initials: JM
authors.lastname: González
authors.affiliation: Department of Chemistry, Faculty of Sciences, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain. Electronic address: manel.alcala@uab.cat.
authors.forename: Manel
authors.initials: M
authors.lastname: Alcalà
mesh_terms: D056804:Biofuels / Q000032:analysis*; D002138:Calibration; D016018:Least-Squares Analysis; D010578:Petroleum / Q000032:analysis; D025341:Principal Component Analysis; D012015:Reference Standards; D015203:Reproducibility of Results; D019265:Spectroscopy, Near-Infrared / Q000379:methods* / Q000592:standards
chemical_list: D056804:Biofuels; D010578:Petroleum
keywords: Biodiesel/diesel blends; Calibration sets selection; Near infrared spectroscopy; Partial least squares regression; Robustness