IMPROVED MOLECULAR CHARACTERIZATION OF PETROLEUM VACUUM RESIDUES BY FT-ICR MS ANALYSIS OF THEIR MOLECULAR DISTILLATION FRACTIONS

摘要

Vacuum residua (VR) are mixtures of extreme complexity andnin spite of the power of ultra high mass resolution techniques such asnthe Fourier Transform Ion Cyclotron Resonance Mass Spectrometryn(FT-ICR MS), they require previous fractionation processes in ordernto avoid the effect of ionic suppression of compounds with lownabundance or low ionization efficiencies.1 Some of the separationntechniques apply nowadays, include liquid chromatography2, SARAn(saturates, aromatics, resins and asphaltenes) method7 andnsupercritical fluid extraction.3 Recently, molecular distillation (MD)nhas been evaluated as fractionation process by measurement ofnphysical and chemical properties of atmospheric residue.4,5 In thisnprocess the samples are separated based on differences in propertiesnas boiling point; fractions with higher boiling points shownconcomitantly higher concentration of polar species, such as resinsnand asphaltenes.