GC/MS Analysis of the Aromatic Composition of Gasoline

The gas chromatography/mass spectrometry (GC/MS) analysis of three brands of regular unleaded gasoline was conducted as part of the independent project of an undergraduate journalism major. In his work, samples of each gasoline were diluted down to part per million (ppm) levels with dichloromethane and then one microliter injections were made onto a Hewlett-Packard GC (5890 Series II unit). Mass spectra were also obtained on each sample through use of a 5971A mass selective detector (MSD).Subsequent characterization was consequently effected through utilization of the standard mass spectra available in a 49,000 compound National Bureau of Standards reference library. Comparison of the obtained and standard spectra revealed that the same aromatic hydrocarbons (including, in part: benzene, the xylenes, naphthalene, and methylated naphthalenes) were present in all three samples. Percentage values for these and other aromatic hydrocarbons were then generated and tabulated.