Quantification of biodiesel and adulteration with vegetable oils in diesel/biodiesel blends using portable near-infrared spectrometer

Author(s)

Paiva, Eduardo Maia ^[1] ; Rodrigues Rohwedder, Jarbas Jose ^[2] ; Pasquini, Celio ^[2] ; Pimentel, Maria Fernanda ^[3] ; Pereira, Claudete Fernandes ^[4]

Affiliation

^[1] Univ Fed Pernambuco, Dept Quim Fundamental, BR-52171030 Recife, PE - Brazil

^[2] Univ Estadual Campinas, Inst Quim, BR-13083970 Campinas, SP - Brazil

^[3] Univ Fed Pernambuco, Dept Engn Quim, BR-50740521 Recife, PE - Brazil

^[4] Univ Fed Pernambuco, Dept Quim Fundamental, BR-50740560 Recife, PE - Brazil

• Document type: Journal article
• Source: FUEL; v. 160, p. 57-63, NOV 15 2015.
• Web of Science Citations: 33

Abstract

The performance of a portable near infrared spectrophotometer to determine biodiesel content in diesel/biodiesel blends, as well as to quantify adulteration by vegetable oil, was evaluated. The NIR transmittance/absorbance spectra of 118 samples in the range 950-1650 nm were acquired using an ultra-compact spectrophotometer (MicroNIR), and also by using a Fourier transform benchtop instrument (FT-NIR) from 800 to 2500 nm. In a preliminary step, partial least squares (PLS) models aimed at the determination of biodiesel quality parameters were developed by using full spectral information. Thereafter, the variables showing significant regression coefficients were selected and the PLS models were re-processed. Successive Projections Algorithm (SPA) was used to screen for the most orthogonal variables to be used in a model constructed by using Multiple Linear Regression (MLR). For determining the contents of both biodiesel and vegetable oil in diesel/biodiesel blends, using MicroNIR and FT-NIR, the results indicated MLR-SPA as the best modelling strategy. RMSEP values of 0.22% v/v (MicroNIR) and 0.13% v/v (FT-NIR) for biodiesel and 0.34% v/v (MicroNIR) and 0.22% (FT-NIR) for vegetable oil contents were obtained. LOD values of 0.31% (MicroNIR) and 0.22% (FT-NIR) for biodiesel and 0.40% (MicroNIR) and 0.34% (FT-NIR) for vegetable oil determination were achieved. The results revealed comparable performances between the portable and the benchtop instruments, demonstrating the feasibility of monitoring in situ the quality characteristics of diesel/biodiesel blends according to biodiesel content and for detection of adulteration with vegetable oils by using the portable spectrophotometer. (C) 2015 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 08/57808-1 - National Institute of Advanced Analytical Science and Technology
• Grantee: Celio Pasquini
• Support Opportunities: Research Projects - Thematic Grants