Electrospray Ionization FT-ICR MS Analysis of Polar Compounds in Natural Bitumen of Munaily-Mola Oil Sands and Its Asphaltenes
Abstract
Herein, we present a study of the most polar compounds of Munaily-Mola bitumen and its asphaltenes using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) combined with electrospray ionization (ESI) technology at the molecular level. Spectral peaks of the negative ion ESI FT-ICR MS mass spectra of Munaily-Mola asphaltene are more intense at the low end of the mass, indicating the presence of more aromatic compounds. Molecular composition analysis of Munaily-Mola bitumen and its asphaltene samples shows that asphaltenes are enriched in compounds such as O2, N2, N1O2, N1, N1O1, N2O1, O4S1, O4, N1O3, O3, O3S1, O1, O5S1, O2S1, N1O4, O5, among which O2 compounds had the highest relative abundance. The relative abundance of O2 compounds is related to the petroleum acid content in the crude oil used to produce asphaltene. The distribution of DBE values in Munaily-Mola asphaltene is higher than DBE values in Munaily-Mola bitumen. Accordingly, the distribution center gravity of asphaltene is also high. This indicates that the highly aromatic compounds in bitumen are concentrated in asphaltenes.