title: Total sulfur determination in residues of crude oil distillation using FT-IR/ATR and variable selection methods.
abstract: Total sulfur concentration was determined in atmospheric residue (AR) and vacuum residue (VR) samples obtained from petroleum distillation process by Fourier transform infrared spectroscopy with attenuated total reflectance (FT-IR/ATR) in association with chemometric methods. Calibration and prediction set consisted of 40 and 20 samples, respectively. Calibration models were developed using two variable selection models: interval partial least squares (iPLS) and synergy interval partial least squares (siPLS). Different treatments and pre-processing steps were also evaluated for the development of models. The pre-treatment based on multiplicative scatter correction (MSC) and the mean centered data were selected for models construction. The use of siPLS as variable selection method provided a model with root mean square error of prediction (RMSEP) values significantly better than those obtained by PLS model using all variables. The best model was obtained using siPLS algorithm with spectra divided in 20 intervals and combinations of 3 intervals (911-824, 823-736 and 737-650 cm(-1)). This model produced a RMSECV of 400 mg kg(-1) S and RMSEP of 420 mg kg(-1) S, showing a correlation coefficient of 0.990.
authors.affiliation: Departamento de Química, Universidade Federal de Santa Maria, Campus, 97105-900 Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: Aline Lima Hermes
authors.initials: AL
authors.lastname: Müller
authors.forename: Rochele Sogari
authors.initials: RS
authors.lastname: Picoloto
authors.forename: Paola
authors.initials: P
authors.lastname: de Azevedo Mello
authors.forename: Marco Flores
authors.initials: MF
authors.lastname: Ferrão
authors.forename: Maria
authors.initials: M
authors.lastname: de Fátima Pereira dos Santos
authors.forename: Regina Célia Lourenço
authors.initials: RC
authors.lastname: Guimarães
authors.forename: Edson Irineu
authors.initials: EI
authors.lastname: Müller
authors.forename: Erico Marlon Moraes
authors.initials: EM
authors.lastname: Flores
mesh_terms: D000465:Algorithms; D002138:Calibration; D016018:Least-Squares Analysis; D010578:Petroleum / Q000032:analysis*; D012680:Sensitivity and Specificity; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013455:Sulfur / Q000032:analysis*
chemical_list: D010578:Petroleum; D013455:Sulfur