Maillard Julien F, Le Maître Johann, Rüger Christopher P, Ridgeway Mark, Thompson Christopher J, Paupy Benoit, Hubert-Roux Marie, Park Melvin, Afonso Carlos, Giusti Pierre
Normandie Université, COBRA, UMR 6014 et FR 3038, Université de Rouen, INSA de Rouen-Normandie, CNRS, IRCOF, Mont Saint Aignan Cedex, France.
International Joint Laboratory - iC2MC: Complex Matrices Molecular Characterization, TRTG, BP 27, 76700 Harfleur, France and Joint Mass Spectrometry Centre/Chair of Analytical Chemistry, University of Rostock, 18059 Rostock, Germany and Department Life, Light & Matter (LLM), University of Rostock, 18051 Rostock, Germany.
Analyst. 2021 Jun 28;146(13):4161-4171. doi: 10.1039/d1an00140j.
Molecular characterization of compounds present in highly complex mixtures such as petroleum is proving to be one of the main analytical challenges. Heavy fractions, such as asphaltenes, exhibit immense molecular and isomeric complexity. Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) with its unequalled resolving power, mass accuracy and dynamic range can address the isobaric complexity. Nevertheless, isomers remain largely inaccessible. Therefore, another dimension of separation is required. Recently, ion mobility mass spectrometry has revealed great potential for isomer description. In this study, the combination of trapped ion mobility and Fourier transform ion cyclotron resonance mass spectrometry (TIMS-FTICR) is used to obtain information on the structural features and isomeric diversity of vanadium petroporphyrins present in heavy petroleum fractions. The ion mobility spectra provided information on the isomeric diversity of the different classes of porphyrins. The determination of the collision cross section (CCS) from the peak apex allows us to hypothesize about the structural aspects of the petroleum molecules. In addition, the ion mobility signal full width at half maximum (FWHM) was used as a measure for isomeric diversity. Finally, theoretical CCS determinations were conducted first on core structures and then on alkylated petroporphyrins taking advantage of the linear correlation between the CCS and the alkylation level. This allowed the proposal of putative structures in agreement with the experimental results. The authors believe that the presented workflow will be useful for the structural prediction of real unknowns in highly complex mixtures.
对石油等高复杂混合物中存在的化合物进行分子表征，正成为主要的分析挑战之一。重质馏分，如沥青质，表现出巨大的分子和异构体复杂性。傅里叶变换离子回旋共振质谱（FTICR MS）凭借其无与伦比的分辨能力、质量精度和动态范围，可以解决同量异位素的复杂性问题。然而，异构体在很大程度上仍然难以分析。因此，需要另一个分离维度。最近，离子淌度质谱在异构体描述方面显示出巨大潜力。在本研究中，采用捕集离子淌度与傅里叶变换离子回旋共振质谱联用（TIMS-FTICR）来获取重质石油馏分中钒卟啉的结构特征和异构体多样性信息。离子淌度谱提供了不同卟啉类别的异构体多样性信息。通过峰顶点确定碰撞截面（CCS），使我们能够对石油分子的结构方面进行推测。此外，离子淌度信号的半高宽（FWHM）被用作异构体多样性的度量。最后，利用CCS与烷基化水平之间的线性相关性，首先对核心结构，然后对烷基化卟啉进行理论CCS测定。这使得我们能够提出与实验结果一致的推定结构。作者认为，所提出的工作流程将有助于对高复杂混合物中真正未知物的结构进行预测。
