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.

中文翻译：

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高效薄层色谱-激光解吸电离傅立叶变换离子回旋共振质谱联用分析硅胶和纤维素固定相以分析沥青

沥青是一种复杂的混合物，对应于原油真空蒸馏的残渣。可以根据极性和溶解度将其与饱和酸酯，芳烃，树脂和沥青质（SARA）分馏分离。高性能薄层色谱适合分析复杂的混合物，例如石油产品，可根据化合物的极性对其进行分离。在这项工作中，HPTLC和激光解吸电离（LDI）傅立叶变换离子回旋共振质谱（FTICR）之间的直接耦合得到了开发和优化，以用于沥青的表征。测试了硅胶和纤维素固定相以分离沥青样品。用纤维素获得较高的信噪比（S / N），而用硅胶观察到不可逆的吸附现象。以纤维素为固定相，使用庚烷和乙醇80:20（v / v）的混合物将沥青样品分为两个区域。另外，实现了用庚烷对沥青的人工分馏，以将馏分用作标准。通过两个区域之间离子分布的差异以及非洗脱区域上富勒烯离子的形成来强调沥青的分离。确实，N₂，N ₁ S ₂，N ₂ S ₁和N ₂ O ₁类主要出现在非洗脱区，而HC，O ₁，O ₂和O ₁ S ₁类大多在洗脱区上发现。此外，DBE与C＃的关系图突出显示DBE值较高的化合物在非洗脱区上。这些结果以及沥青样品的手工分馏，使人们得以确认未洗脱区对应于沥青质，而洗脱区对应于麦芽烯。总的来说，这项研究表明使用HPTLC分离技术可以快速分离和表征沥青质和麦芽馏分。