Determination of detergent and dispensant additives in gasoline by ring-oven and near infrared hypespectral imaging.
A method using the ring-oven technique for pre-concentration in filter paper discs and near infrared hyperspectral imaging is proposed to identify four detergent and dispersant additives, and to determine their concentration in gasoline. Different approaches were used to select the best image data processing in order to gather the relevant spectral information. This was attained by selecting the pixels of the region of interest (ROI), using a pre-calculated threshold value of the PCA scores arranged as histograms, to select the spectra set; summing up the selected spectra to achieve representativeness; and compensating for the superimposed filter paper spectral information, also supported by scores histograms for each individual sample. The best classification model was achieved using linear discriminant analysis and genetic algorithm (LDA/GA), whose correct classification rate in the external validation set was 92%. Previous classification of the type of additive present in the gasoline is necessary to define the PLS model required for its quantitative determination. Considering that two of the additives studied present high spectral similarity, a PLS regression model was constructed to predict their content in gasoline, while two additional models were used for the remaining additives. The results for the external validation of these regression models showed a mean percentage error of prediction varying from 5 to 15%.
Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil.
Lívia
L
Rodrigues e Brito
Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil.
Michelle P F
MP
da Silva
Instituto de Química, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil.
Jarbas J R
JJ
Rohwedder
Instituto de Química, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil.
Celio
C
Pasquini
Departamento de Engenharia Química, Universidade Federal de Pernambuco - UFPE, Avenida Prof. Arthur de Sá s/n, Cidade Universitária, 50740-521 Recife, PE, Brazil.
Fernanda A
FA
Honorato
Departamento de Engenharia Química, Universidade Federal de Pernambuco - UFPE, Avenida Prof. Arthur de Sá s/n, Cidade Universitária, 50740-521 Recife, PE, Brazil. Electronic address: mfernanda.pimentel@ufpe.br.
Maria Fernanda
MF
Pimentel
Detergent dispersant additives; Gasoline; Hyperspectral imaging; Near infrared spectroscopy; Ring oven