Ion mobility mass spectrometry for structural elucidation of petroleum compounds

To gain insight into the chemical composition and characteristics of petroleum, its characterization and structural identification at the molecular level is essential. To this aim, mass spectrometry techniques, especially ultrahigh-resolution mass spectrometry and its coupling with other complementary tools such as hydrogen–deuterium exchange, tandem mass spectrometry are important analytical methods. In particular, the analytical power of ion mobility (IM) coupled with high-resolution mass spectrometry (IMMS) in structural characterization has expanded its scope from biomolecules to petroleum since 2009, providing improved peak capacities and more accurate structural assignments in petroleum samples. The separation of gas-phase ions in IM devices is based on their size or shape (e.g., collisional cross section), charge, and drift gas. Information on the structure of petroleum ions is then obtained by comparing the theoretical and experimental collision cross-sections obtained using IMMS. Considering the relevance that the construction of a systematic guideline of IMMS for the molecular characterization of petroleum would have in the context of petroleum technology, we describe in this review some instructive examples of the application of IMMS to the analysis of petroleum compounds and petroleum products, along with its future perspective, with the aim of providing a potent guide for petroleum specialists who want a comprehensive and concise overview of the implications of the IMMS technology for petroleum analysis.