Comparison of Silica and Cellulose Stationary Phases to Analyze Bitumen by High-Performance Thin-Layer Chromatography Coupled to Laser Desorption Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Abstract

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.

Molecular Characterization of a Mixed Plastic Pyrolysis Oil from Municipal Wastes by Direct Infusion Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

“…Pyrolysis oils are described as complex mixtures and ultrahigh-resolution mass spectrometry is required to have an advanced molecular description . Fourier transform ion cyclotron resonance (FTICR) mass spectrometers with a high magnetic field offer the best performances in terms of resolution, mass accuracy, and dynamic range. − Over the past 20 years, it has been widely used to decipher ultracomplex mixtures. − In the case of plastic pyrolysis oil, two studies using FTICR-MS reported their molecular characterization with atmospheric pressure photoionization (APPI). This enabled the characterization of hydrocarbon compounds and a part of oxygenated compounds defined as alcohols. , However, as stated before, the molecular characterization of other heteroatom-containing species such as nitrogen species is also important in order to anticipate their impact on the refining process. − Depending on the ionization method, different ionization selectivities can be obtained in order to detect specific families of compounds.…”

Speciation of Metals in Asphaltenes by High-Performance Thin-Layer Chromatography and Solid–Liquid Extraction Hyphenated with Elemental and Molecular Identification

“…A hybrid quadrupole FT-ICR instrument (SolariXR, Bruker Daltonics, Bremen, Germany) equipped with a 12 T superconducting magnet was equipped with an LDI/MALDI source with a Nd:YAG × 3 solid-state laser (355 nm) . Broadband mass spectra were acquired over a mass range of m / z 147–1000 with an accumulation of 200 scans.…”

“…MALDI FT-ICR MS. A hybrid quadrupole FT-ICR instrument (SolariXR, Bruker Daltonics, Bremen, Germany) equipped with a 12 T superconducting magnet was equipped with an LDI/MALDI source with a Nd:YAG × 3 solid-state laser (355 nm). 30 Broadband mass spectra were acquired over a mass range of m/z 147−1000 with an accumulation of 200 scans. The signal was digitalized with 8 M points, resulting in a transient length of 3.4 s; this gave a resolving power number of 0.9 × 10 6 at m/z 400.…”

Next Challenges for the Comprehensive Molecular Characterization of Complex Organic Mixtures in the Field of Sustainable Energy

“…Rodgers et al used a similar approach by considering the modified aminopropyl silica (MAPS) fractionation of bitumen [181]. Lacroix-Andrivet et al used another methodology by combining high-performance thin-layer chromatography (HPTLC) and laser desorption-ionization (LDI) FT-ICR MS to analyze bitumen [182]. The HPTLC of bitumen on cellulose with a heptane/ethanol solvent mixture ensured the separation of maltenes and asphaltenes.…”