Compositional changes in weathered transportation fuels monitored by electron ionization Fourier transform ion cyclotron mass spectrometry

Conventional methods do not provide complete compositional information at the molecular level for weathered oils to evaluate the environmental impact of petroleum products. Low voltage (10 ev) electron ionization (EI) 7 T Fourier transform ion cyclotron resonance MS (FT-ICR MS) for characterization of unweathered and evaporatively weathered diesel and kerosene standards is presented. Ultra-high mass resolving power and mass accuracy afforded by FT-ICR MS allow for unambiguous elemental composition assignment. Hundreds of compositions in each sample, including aromatic hydrocarbons and S-, N-, O-containing compounds, without prior fractionation, are identified. A gradual increase in the number and relative abundance of heteroatomic compound classes as the extent of weathering increases is observed. Type (rings plus double bonds) and carbon number (extent of alkylation) distribution for hydrocarbons reveal preferential removal of less aromatic and lower molecular weight compounds. This is an abstract of a paper presented at the 231th ACS National Meeting (Atlanta, GA 3/26-30/2006).