Atmospheric Pressure Photoionization and Laser Desorption Ionization Coupled to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry To Characterize Asphaltene Solubility Fractions: Studying the Link between Molecular Composition and Physical Behavior

Abstract

In the present work, a series of asphaltene solubility fractions extracted from a heavy crude oil have been analyzed using laser desorption ionization (LDI) and atmospheric pressure photoionization (APPI) coupled to Fourier transform ion cyclotron resonance mass spectrometry. The objective is to find how molecular compositional data compare and correlate to information found using other techniques. To accomplish this comparison, a methodology to link the compositional information and the macroscopic behavior is presented and successfully used. In general, we found that average H/C ratios and molecular weights were lower and average densities and average solubility parameters were larger than those determined by other techniques. Values obtained from APPI data were closer than those obtained by LDI data to the reference values. This is indicative that, to estimate bulk properties, APPI might be better suited than LDI. Solubility parameter distributions obtained using APPI data for the classes were shifted ...