Determination of Weight Percent Oxygen in Commercial Gasoline: A Comparison between FT-Raman,FT-IR,and Dispersive Near-IR Spectroscopies

The weight percent oxygen in commercial gasoline samples has been determined by using partial least-squares (PLS) regression analysis combined with either FT-Raman, FT-IR, or dispersive near-IR spectroscopy. Calibration models were constructed with the use of 33 MTBE oxygenated commercial gasolines. The minimum standard errors of validation with the use of leave-one-out validation are 0.156, 0.188, and 0.119 wt % oxygen for FT-Raman, FT-IR, and near-IR, respectively. An independent test set of 36 MTBE oxygenated commercial gasolines was used to further validate the PLS models. The minimum standard errors of prediction for the test set are 0.155, 0.143, and 0.131 wt % oxygen for FT-Raman, FT-IR, and near-IR, respectively. The wt % oxygen in all samples ranges from 0.2 to 3.262%.