Crude oil was subjected to extrography to obtain various acid compounds in multiple subfractions. Negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and gas chromatography mass spectrometry (GC-MS) were used to determine the acid compounds in the crude oil subfractions. Isoprenoidyl phenols with molecular formulas of C27H48O and C28H50O, which were previously deduced as sterol-type compounds, were highly enriched in a subfraction and confirmed by GC-MS. The mass peak with a molecular formula of C27H46O2 was identified as delta-tocopherol. The eluting sequence of the various compounds in crude oil was NI carbazoles, followed by O-1 class acid compounds, then O-2 class acid compounds, and finally, N1O2, 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 subfractions.