In this work, crude oil asphaltenes
obtained using n-pentane in the presence of different
minerals (sand and iron oxide)
were analyzed using atmospheric pressure photoionization coupled to
ultrahigh-resolution magnetic resonance mass spectrometry. Results
indicate that these minerals induce a slightly larger amount of precipitated
material than when n-pentane is used alone. The asphaltenes
precipitated in the presence of the substrates also have higher hydrogen/carbon
molar ratios. All detected classes showed lower average double bond
equivalents independent of whether they become more or less abundant
in the iron-oxide- or sand-precipitated asphaltenes. Additionally,
there was an increase in some of the oxygen-containing species compared
to the asphaltene precipitated using the standard method. This study
gives additional evidence that the characteristics of asphaltene deposits
are highly dependent upon the conditions and, in this case, the effect
of inorganic material.