Bitumen
is a complex mixture corresponding to the residue of the
vacuum distillation of crude oil. It can be separated on the basis
of polarity and solubility with saturates, aromatics, resins, and
asphaltenes (SARA) fractionation. High-performance thin-layer chromatography
is suited to analyze complex mixtures such as petroleum products,
which separates compounds according to their polarity. In this work,
the direct coupling between HPTLC and laser desorption ionization
(LDI) Fourier transform ion cyclotron resonance mass spectrometry
(FTICR) was developed and optimized for the characterization of bitumen.
Silica gel and cellulose stationary phases were tested to separate
bitumen samples. A higher signal-to-noise ratio (S/N) was obtained
with cellulose, whereas an irreversible adsorption phenomenon was
observed with silica gel. With cellulose as a stationary phase, the
bitumen sample was separated into two zones using a mixture of heptane
and ethanol 80:20 (v/v). In addition, manual fractionation of bitumen
with heptane was realized to use the fractions as standards. The separation
of bitumen was underlined by the difference of ion distribution between
the two zones and the formation of fullerene ions on the noneluted
zone. Indeed, N2, N1S2, N2S1, and N2O1 classes were mainly
found in the noneluted zone, whereas HC, O1, O2, and O1S1 classes were mostly found on the
eluted zone. Additionally, the DBE versus C# maps highlighted that
the compounds with the higher DBE values were on the noneluted zone.
These results as well as the manual fractionation of bitumen sample
allowed one to confirm that the noneluted zone corresponded to asphaltenes
and the eluted zone corresponded to maltenes. Overall, this study
showed a fast separation and characterization of asphaltene and maltene
fractions using HPTLC separation.