A new method for alcohol content determination of fuel oils by terahertz spectroscopy

In this study, we developed a simple method for alcohol content analysis in fuel oils by Time-Domain Terahertz (THz) Spectroscopy. Frequency dependent absorption coefficients, refractive indices, and dielectric constants were calculated from the measurements of pure fuel oils and their mixtures with ethanol. Ethanol mixtures of gasoline were modeled successfully with a simple model in which the mixture behavior was described with a basic contribution approach of pure liquids. The results suggest that there is no strong interaction between the ethanol and the molecules in the gasoline. We concluded that this new approach offers a simple and useful method to determine the concentration of ethanol in gasoline currently with a 3% (by volume) maximum absolute error. With improvements, this error would be reduced to below 1%.