Motor gasoline contains dozens of types of aromatic compounds, i.e., organic substances with a carbon ring: their composition determines fuel grades, such as AI-92, AI-95 and AI-98. The more aromatic compounds are contained in gasoline, the higher the octane number, which leads gasoline to burn more completely and evenly. If the aromatic compound content in gasoline is too low, the liquid could be prone to carbon deposition, which causes rapid engine wear.
Today, the composition of gasoline is determined through liquid chromatography: a sample of gasoline mixed with a solvent is poured into a tube filled with a sorbent. When it passes through the tube, gasoline is separated into fractions, as the substances flow through the sorbent at different speeds. Toxic and flammable substances like hexane, methylene chloride or acetonitrile are usually used as solvents. This is why scientists are looking for safer ways to determine gasoline composition.
To that end, the scientists from Ivanovo and Khabarovsk have proposed using the luminophore substance BODIPY, the glow of which depends on individual components of gasoline. The authors obtained this compound by mixing pyrrole, an organic compound formed by a ring of carbon and nitrogen atoms, and benzaldehyde, a carbon ring with oxygen.
The authors added the luminophore to gasoline after measuring its density and viscosity. The resulting sample was then placed in a spectrofluorimeter, a device that reads the wavelength and intensity of the sensor glow, assessing the amount of aromatic components in petroleum products. In order to assess the effectiveness of the new method, the scientists determined the composition of the very same sample using liquid chromatography.
They found that BODIPY makes it possible to determine the content of aromatic compounds with a margin of error of no more than 3%. The scientists also managed to establish a connection between the amount of aromatic compounds, viscosity and fluorescence intensity: the more aromatic compounds are contained in gasoline, the higher its viscosity and the stronger the sensor glow.
“In the future, we plan to refine the luminophore compounds to ensure greater sensitivity and a smaller margin of error in determining the amount of aromatic compounds. Thanks to our study, enterprises will be able to start using more user-friendly sensor materials, including reusable ones. And by combining several luminophores, we will be able to expand the list of detectable substances in samples,” Yury Marfin, doctor of chemical sciences, is quoted as saying by the Russian Science Foundation.
