Paper Title
Detection and Estimation of Kerosene in Gasoline using Fourier Transform Infrared Spectroscopy and Multivariate Technique

Abstract
Adulteration of hydrocarbon fuel is rampant in South Asia including India. One of the most common act of adulteration is blending gasoline with kerosene which changes the physical and chemical properties of the fuel and often leads to increase tail pipe emission, reduce engine lifetime, lowering the octane number and engine knocking. Determination of kerosene in gasoline is not easy due to similarity in the molecular structure of the hydrocarbon compositions. The present work reported the detection and estimation of the adulterant in gasoline employing multivariate methods- Principal Component Analysis (PCA) and Partial Least Square Regression (PLS-R) technique as applied to FTIR spectral data of the test samples. The IR spectral bands most sensitive to kerosene are the alkyl modes in the 2700-3200 cm-1 region. This spectral region is the region where the tested samples exhibit largest variation among themselves in the PCA results which can be make use to detect kerosene or other bigger hydrocarbon adulterants. Kerosene adulteration of gasoline increases the proportion of bigger hydrocarbon content in the base fuel beyond the specified composition. A PLS calibration model was developed using standard samples containing different concentration of kerosene in the range 0 to 24% (v/v) in the alkyl modes region. Figure 1 shows how the CH3 and CH2 alkyl modes varies with increase in kerosene concentration. The calibration curve has R2 = 0.99742 with RMSE = 0.4368732 indicating very high correlation between kerosene concentration and the alkyl modes. With reference to the Kerosene-Prediction model, over 177 number of samples were tested for kerosene and observed that, among all the samples 56% samples contain kerosene less than 10%; 35% samples contain 11-20% kerosene and below 6% samples contain 21-30% kerosene. Keywords – Kerosene, Alkyl Modes, Hydrocarbon Adulterants, Molecular Structure