Partitioning of Crude Oil Acidic Compounds into Subtractions by Extrography and Identification of Isoprenoidyl Phenols and Tocopherols

摘要

Crude oil was subjected to extrography to obtain various acid compounds in multiple subtractions. Negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and gas chromatogra-phy-mass spectrometry (GC-MS) were used to determine the acid compounds in the crude oil subtractions. Isoprenoidyl phenols with molecular formulas of C_(27)H_(48)O and C_(28)H_(50)O, which were previously deduced as sterol-type compounds, were highly enriched in a subtraction and confirmed by GC -MS. The mass peak with a molecular formula of C_(27)H_(46)O_2 was identified as δ-tocopherol. The eluting sequence of the various compounds in crude oil was N_1 carbazoles, followed by O_1 class acid compounds, then O_2 class acid compounds, and finally, N_1O_2,O_3, and O_4 class acid compounds. The results show that extrography is an adequate separation technique for partitioning crude oil acid compounds into various subtractions.