Nonpolar Compositional Analysis of Vacuum Gas Oil Distillation Fractions by Electron Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

We analyzed three vacuum gas oil distillation fractions, 295−319 °C, 319−456 °C, and 456−543 °C, with a home-built external electron ionization (EI) 7 T Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. EI at 10 eV allows soft ionization of aromatic compounds in the vacuum gas oil range. Unambiguous elemental composition assignment provides insight into compositional variations at the molecular level; for example, ultrahigh resolving power (m/Δm50% ≈ 300 000 at m/z 300) and mass accuracy (<0.4 ppm) readily resolve C3/SH4 doublets (3.4 mDa mass difference) across the full m/z range of interest. To our knowledge, this is the first time that hydrocarbons and sulfur-containing hydrocarbons have been completely mass-resolved across the full VGO range. Aromatic hydrocarbons are the major detected components in all three samples. In addition, many sulfur-, nitrogen-, and oxygen-containing compounds were directly observed. The concentrations of the heteroatomic species increase with boiling po...