Investigation of the relative abundances of single-core and multicore compounds in asphaltenes by using high-resolution in-source collision-activated dissociation and medium-energy collision-activated dissociation mass spectrometry with statistical considerations

Compositional Trends for Total Vanadium Content and Vanadyl Porphyrins in Gel Permeation Chromatography Fractions Reveal Correlations between Asphaltene Aggregation and Ion Production Efficiency in Atmospheric Pressure Photoionization

“…Recent works from the National High Magnetic Field Laboratory have highlighted the utility of the technique to investigate potential asphaltene structural motifs by tandem-MS, which demonstrated that single-core, "island" motifs coexist with those composed of multiple aromatic cores linked by covalent bonds (multicore or "archipelago"). 29,30 These findings were also supported by Wittrig, 31 Ruger, 32−34 Nyadong, 35 and Kenttamaa et al 36 Moreover, gas-phase fragmentation studies of geologically diverse asphaltene samples have revealed that the dominance of a particular structural motif (island or archipelago) is sample-dependent and correlates with the chemistry/structure of products from thermal cracking processes. These reports, along with recent findings by Xu, 23,24,37 Harbottle, 38 Clingenpeel, 39 and Jarvis et al, 40 challenge the idea of the uniform dominance of highly aromatic/single-core structures in petroleum asphaltene samples and strongly suggest the existence of abundant multi-core "archipelago" species as well as heptane-insoluble/ toluene-soluble compounds with "atypical" low aromaticity but high heteroatom content (i.e., oxygen and sulfur).…”

“…, crude oil, petroleum distillates, and dissolved organic matter) because of its inherent high resolution and accurate mass measurement capabilities that facilitate the assignment of individual elemental compositions to tens-of-thousands of species in a single sample in a matter of minutes by mass measurement alone. , For instance, McKenna et al reported the detection of ∼85,000 species in a natural petroleum seep sample in which the authors identified nickel and vanadyl porphyrins with unprecedented mass accuracy. Recent works from the National High Magnetic Field Laboratory have highlighted the utility of the technique to investigate potential asphaltene structural motifs by tandem-MS, which demonstrated that single-core, “island” motifs coexist with those composed of multiple aromatic cores linked by covalent bonds (multicore or “archipelago”). , These findings were also supported by Wittrig, Rüger, − Nyadong, and Kenttämaa et al Moreover, gas-phase fragmentation studies of geologically diverse asphaltene samples have revealed that the dominance of a particular structural motif (island or archipelago) is sample-dependent and correlates with the chemistry/structure of products from thermal cracking processes. These reports, along with recent findings by Xu, ,, Harbottle, Clingenpeel, and Jarvis et al , challenge the idea of the uniform dominance of highly aromatic/single-core structures in petroleum asphaltene samples and strongly suggest the existence of abundant multi-core “archipelago” species as well as heptane-insoluble/toluene-soluble compounds with “atypical” low aromaticity but high heteroatom content ( i.e.…”

Molecular Characterization of Strongly and Weakly Interfacially Active Asphaltenes by High-Resolution Mass Spectrometry

“…In an attempt to determine the predominant structure (single-core or multi-core) of IAA and RA, precursor ions of relatively high molecular weight ( m / z 650), where multi-core structures are likely to be observed (if they are present), − were isolated via mass-resolving quadrupole and SWIFT multi-notch and fragmented by IRMPD (see Figure for the fragmentation spectra). Fragmentation data of lower molecular weight ( m / z 450) ions are shown in the Supporting Information to highlight the sensitivity of the single-core/multi-core predominance on molecular weight.…”

Distinguishing Isomeric Aromatic Radical Cations by Using Energy-Resolved Ion Trap and Medium Energy Collision-Activated Dissociation Mass Spectrometry

“…Direct comparison of ITCAD and MCAD was recently published for proteomics research. − Compared to ITCAD, the use of MCAD improved both protein quantitation precision and accuracy of peptide identification. , Application of MCAD in other fields is also likely to prove beneficial. While previous studies have demonstrated successful structural characterization of ions derived from petroleum by using ITCAD, , only limited information is available on the application of MCAD to petroleum-based samples or related model compounds …”

“…While previous studies have demonstrated successful structural characterization of ions derived from petroleum by using ITCAD, 13,14 only limited information is available on the application of MCAD to petroleum-based samples or related model compounds. 15 It is noteworthy that the fragmentation patterns of isomeric ions subjected to CAD can be highly sensitive to the collision energy in the low ion kinetic energy regime (1−100 eV). 7,16 Therefore, examination of ion fragmentation patterns at different collision energies, as opposed to a single energy, often provides invaluable structural information that enables the differentiation of ion internal energy effects from structural differences between isomeric ions.…”