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Publikasjoner (10 av 125) Visa alla publikasjoner
Sjövall, P., Zhang, Y., Ruiz-Morales, Y. & Mullins, O. (2023). Evaluation of Molecular Fragmentation in Polycyclic Aromatic Hydrocarbons by Time-of-Flight Secondary Ion Mass Spectrometry. Energy & Fuels, 37, 7071
Åpne denne publikasjonen i ny fane eller vindu >>Evaluation of Molecular Fragmentation in Polycyclic Aromatic Hydrocarbons by Time-of-Flight Secondary Ion Mass Spectrometry
2023 (engelsk)Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 37, s. 7071-Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

In time-of-flight secondary ion mass spectrometry (TOF-SIMS), ionized molecules and molecular fragments (secondary ions) are generated in collisions of high-energy ions (primary ions) with a solid sample surface. Mass spectra of the emitted secondary ions are typically used to identify molecular species and to determine their spatial distribution on the sample surface. Here, we extend this application in a TOF-SIMS study of a series of polycyclic aromatic hydrocarbons (PAHs) where we focus on the fragmentation of these molecules, with the purpose of better understanding the fragmentation patterns of heavy aromatic molecules in petroleum. For all PAHs, the collision process generated (i) a series of smaller cation fragments and (ii) cations close in size to the original PAH (molecular cations). Stark differences are measured for various PAHs regarding the abundance of smaller fragments versus molecular cations. Observation of hydrogen-deficient (H-deficient) cation fragments indicates the formation of polyynes and allenes. For PAHs producing higher fractions of small cation fragments, these ions are surprisingly hydrogen rich (H-rich). The H/C ratio of fragments does not scale with the fraction of Clar sextet carbon, nor with energies of low-lying electronic transitions. Free radical cation fragments tend to be suppressed. For sufficiently large fragments, aromatic cations appear to be formed and include some free radical aromatics. There is ample production of molecular ions with loss of a single carbon atom or a methine group, which corresponds to the reduction of a 6-membered aromatic ring to a 5-membered ring. There is some enhancement of free radical molecular cations due to the corresponding formation of neutral polyynes. Fragment anions are also produced with a strong preference for very H-deficient carbon clusters, in some cases being the same as carbon cluster anions observed in space. Comparisons of PAH TOF-SIMS spectra with those of asphaltenes are discussed in detail.

sted, utgiver, år, opplag, sider
American Chemical Society, 2023
Emneord
Aromatization, Free radicals, Hydrogen, Ion sources, Molecules, Organic polymers, Positive ions, Secondary emission, Secondary ion mass spectrometry, High-energy ions, Ionized molecules, Molecular cations, Molecular fragmentation, Molecular fragments, Polyynes, Primary ions, Sample surface, Secondary ions, Time of flight secondary ion mass spectrometry, Polycyclic aromatic hydrocarbons
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-64952 (URN)10.1021/acs.energyfuels.3c00098 (DOI)2-s2.0-85159623217 (Scopus ID)
Merknad

 Vetenskapsrådet, VR, 2019-03731; Funding text 1: Financial support for this work was provided by the Swedish Research Council, grant no 2019-03731 (PS).

Tilgjengelig fra: 2023-06-09 Laget: 2023-06-09 Sist oppdatert: 2023-06-09bibliografisk kontrollert
De La Garza, R., Sjövall, P., Hauff, R. & Lindgren, J. (2023). Preservational modes of some ichthyosaur soft tissues (Reptilia, Ichthyopterygia) from the Jurassic Posidonia Shale of Germany. Palaeontology, 66(4), Article ID e12668.
Åpne denne publikasjonen i ny fane eller vindu >>Preservational modes of some ichthyosaur soft tissues (Reptilia, Ichthyopterygia) from the Jurassic Posidonia Shale of Germany
2023 (engelsk)Inngår i: Palaeontology, ISSN 0031-0239, E-ISSN 1475-4983, Vol. 66, nr 4, artikkel-id e12668Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Konservat-Lagerstätten, such as the Toarcian (Early Jurassic) Posidonia Shale of southwestern Germany, are renowned for their spectacular fossils. Ichthyosaur skeletons recovered from this formation are frequently associated with soft tissues; however, the preserved material ranges from three-dimensional, predominantly phosphatized structures to dark films of mainly organic matter. We examined soft-tissue residues obtained from two ichthyosaur specimens using an integrated ultrastructural and geochemical approach. Our analyses revealed that the superficially-looking ‘films’ in fact comprise sections of densely aggregated melanosome (pigment) organelles sandwiched between phosphatized layers containing fibrous microstructures. We interpret this distinct layering as representing condensed and incompletely degraded integument from both sides of the animal. When compared against previously documented ichthyosaur fossils, it becomes readily apparent that a range of preservational modes exists between presumed ‘phosphatic’ and ‘carbonized’ soft-tissue remains. Some specimens show high structural fidelity (e.g. distinct integumentary layering), while others, including the fossils examined in this study, retain few original anatomical details. This diversity of soft-tissue preservational modes among Posidonia Shale ichthyosaurs offers a unique opportunity to examine different biostratinomic, taphonomic and diagenetic variables that potentially could affect the process of fossilization. It is likely that soft-tissue preservation in the Posidonia Shale was regulated by a multitude of factors, including decay efficiency and speed of phosphatic mineral nucleation; these in turn were governed by a seafloor with sustained microbial mat activity fuelled by high organic matter input and seasonally fluctuating oxygen levels. © 2023 The Authors. 

sted, utgiver, år, opplag, sider
John Wiley and Sons Inc, 2023
Emneord
Holzmaden, ichthyosaur, Jurassic, skin, soft tissue, taphonomy
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-65666 (URN)10.1111/pala.12668 (DOI)2-s2.0-85165924248 (Scopus ID)
Merknad

Grant for Distinguished Young Researchers (Swedish Research Council, No. 642-2014-3773) awarded to JL and a Project Grant (Swedish Research Council, No. 2019-03731) 

Tilgjengelig fra: 2023-08-07 Laget: 2023-08-07 Sist oppdatert: 2023-08-07bibliografisk kontrollert
Slater, T. S., Ito, S., Wakamatsu, K., Zhang, F., Sjövall, P., Jarenmark, M., . . . McNamara, M. E. (2023). Taphonomic experiments reveal authentic molecular signals for fossil melanins and verify preservation of phaeomelanin in fossils. Nature Communications, 14(1), Article ID 5651.
Åpne denne publikasjonen i ny fane eller vindu >>Taphonomic experiments reveal authentic molecular signals for fossil melanins and verify preservation of phaeomelanin in fossils
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2023 (engelsk)Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 14, nr 1, artikkel-id 5651Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Melanin pigments play a critical role in physiological processes and shaping animal behaviour. Fossil melanin is a unique resource for understanding the functional evolution of melanin but the impact of fossilisation on molecular signatures for eumelanin and, especially, phaeomelanin is not fully understood. Here we present a model for the chemical taphonomy of fossil eumelanin and phaeomelanin based on thermal maturation experiments using feathers from extant birds. Our results reveal which molecular signatures are authentic signals for thermally matured eumelanin and phaeomelanin, which signatures are artefacts derived from the maturation of non-melanin molecules, and how these chemical data are impacted by sample preparation. Our model correctly predicts the molecular composition of eumelanins in diverse vertebrate fossils from the Miocene and Cretaceous and, critically, identifies direct molecular evidence for phaeomelanin in these fossils. This taphonomic framework adds to the geochemical toolbox that underpins reconstructions of melanin evolution and of melanin-based coloration in fossil vertebrates. 

sted, utgiver, år, opplag, sider
Nature Research, 2023
Emneord
Cretaceous; fossil record; maturation; Miocene; signal processing; taphonomy; vertebrate
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-67682 (URN)10.1038/s41467-023-40570-w (DOI)2-s2.0-85173756792 (Scopus ID)
Merknad

Funding sponsors: European Research Council

Tilgjengelig fra: 2023-11-06 Laget: 2023-11-06 Sist oppdatert: 2023-11-06bibliografisk kontrollert
Sjövall, P., Gregoire, S., Wargniez, W., Skedung, L. & Luengo, G. (2022). 3D Molecular Imaging of Stratum Corneum by Mass Spectrometry Suggests Distinct Distribution of Cholesteryl Esters Compared to Other Skin Lipids. International Journal of Molecular Sciences, 23(22), Article ID 13799.
Åpne denne publikasjonen i ny fane eller vindu >>3D Molecular Imaging of Stratum Corneum by Mass Spectrometry Suggests Distinct Distribution of Cholesteryl Esters Compared to Other Skin Lipids
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2022 (engelsk)Inngår i: International Journal of Molecular Sciences, ISSN 1661-6596, E-ISSN 1422-0067, Vol. 23, nr 22, artikkel-id 13799Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The crucial barrier properties of the stratum corneum (SC) depend critically on the design and integrity of its layered molecular structure. However, analysis methods capable of spatially resolved molecular characterization of the SC are scarce and fraught with severe limitations, e.g., regarding molecular specificity or spatial resolution. Here, we used 3D time-of-flight secondary ion mass spectrometry to characterize the spatial distribution of skin lipids in corneocyte multilayer squams obtained by tape stripping. Depth profiles of specific skin lipids display an oscillatory behavior that is consistent with successive monitoring of individual lipid and corneocyte layers of the SC structure. Whereas the most common skin lipids, i.e., ceramides, C24:0 and C26:0 fatty acids and cholesteryl sulfate, are similarly organized, a distinct 3D distribution was observed for cholesteryl oleate, suggesting a different localization of cholesteryl esters compared to the lipid matrix separating the corneocyte layers. The possibility to monitor the composition and spatial distribution of endogenous lipids as well as active drug and cosmetic substances in individual lipid and corneocyte layers has the potential to provide important contributions to the basic understanding of barrier function and penetration in the SC. © 2022 by the authors.

sted, utgiver, år, opplag, sider
MDPI, 2022
Emneord
3D ToF-SIMS, cholesteryl esters, layer structure, lipid distribution, stratum corneum
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-61377 (URN)10.3390/ijms232213799 (DOI)2-s2.0-85142634501 (Scopus ID)
Merknad

Funding details: Vetenskapsrådet, VR, 2019-03731; Funding text 1: Financial support for this work was provided by the Swedish Research Council, grant No. 2019-03731 (P.S.).

Tilgjengelig fra: 2022-12-08 Laget: 2022-12-08 Sist oppdatert: 2023-06-05bibliografisk kontrollert
De La Garza, R. G., Madsen, H., Sjövall, P., Osbӕck, F., Zheng, W., Jarenmark, M., . . . Lindgren, J. (2022). An ancestral hard-shelled sea turtle with a mosaic of soft skin and scutes. Scientific Reports, 12(1), Article ID 22655.
Åpne denne publikasjonen i ny fane eller vindu >>An ancestral hard-shelled sea turtle with a mosaic of soft skin and scutes
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2022 (engelsk)Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 12, nr 1, artikkel-id 22655Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The transition from terrestrial to marine environments by secondarily aquatic tetrapods necessitates a suite of adaptive changes associated with life in the sea, e.g., the scaleless skin in adult individuals of the extant leatherback turtle. A partial, yet exceptionally preserved hard-shelled (Pan-Cheloniidae) sea turtle with extensive soft-tissue remains, including epidermal scutes and a virtually complete flipper outline, was recently recovered from the Eocene Fur Formation of Denmark. Examination of the fossilized limb tissue revealed an originally soft, wrinkly skin devoid of scales, together with organic residues that contain remnant eumelanin pigment and inferred epidermal transformation products. Notably, this stem cheloniid—unlike its scaly living descendants—combined scaleless limbs with a bony carapace covered in scutes. Our findings show that the adaptive transition to neritic waters by the ancestral pan-chelonioids was more complex than hitherto appreciated, and included at least one evolutionary lineage with a mosaic of integumental features not seen in any living turtle. © 2022, The Author(s).

sted, utgiver, år, opplag, sider
Nature Research, 2022
Emneord
animal, epidermis, evolution, reptile, skin, turtle, Animals, Biological Evolution, Reptiles, Turtles
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-62576 (URN)10.1038/s41598-022-26941-1 (DOI)2-s2.0-85145372322 (Scopus ID)
Merknad

Funding details: 642-2014-3773; Funding details: Lunds Universitet; Funding details: Vetenskapsrådet, VR; Funding text 1: Ola Gustafsson prepared samples for TEM and assisted during the analyses. Miriam Heingård assisted during the ToF-SIMS analyses, while Carl Alwmark helped out during the FEG-SEM investigation. Maria Mostadius gave us access to extant testudine material in the collections at the Biological Museum, Lund University. Daniel Johansson provided access to modern turtle skins in the herpetological collection at the Zoological Museum in Copenhagen, Denmark. Raffael Ernst and Markus Auer provided images of Carettochelys skin from the herpetological collection at the Senckenberg Museum in Dresden, Germany. Lars Skou Olsen provided information on resident testudines housed in the collections at the National Aquarium of Denmark. Financial support was provided by a Grant for Distinguished Young Researchers (642-2014-3773; Swedish Research Council) to J.L.; Funding text 2: Ola Gustafsson prepared samples for TEM and assisted during the analyses. Miriam Heingård assisted during the ToF-SIMS analyses, while Carl Alwmark helped out during the FEG-SEM investigation. Maria Mostadius gave us access to extant testudine material in the collections at the Biological Museum, Lund University. Daniel Johansson provided access to modern turtle skins in the herpetological collection at the Zoological Museum in Copenhagen, Denmark. Raffael Ernst and Markus Auer provided images of Carettochelys skin from the herpetological collection at the Senckenberg Museum in Dresden, Germany. Lars Skou Olsen provided information on resident testudines housed in the collections at the National Aquarium of Denmark. Financial support was provided by a Grant for Distinguished Young Researchers (642-2014-3773; Swedish Research Council) to J.L.

Tilgjengelig fra: 2023-01-20 Laget: 2023-01-20 Sist oppdatert: 2023-06-05bibliografisk kontrollert
Pipintakos, G., Ching, H. Y., Mühlich, U., Soenen, H., Van Doorslaer, S., Sjövall, P., . . . Lu, X. (2022). Experimental Validation of the Dual-Oxidation Routes in Bituminous Binders. In: RILEM Bookseries: . Paper presented at - (pp. 903-909). Paper presented at -. Springer Science and Business Media B.V., 27
Åpne denne publikasjonen i ny fane eller vindu >>Experimental Validation of the Dual-Oxidation Routes in Bituminous Binders
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2022 (engelsk)Inngår i: RILEM Bookseries, Springer Science and Business Media B.V. , 2022, Vol. 27, s. 903-909Kapittel i bok, del av antologi (Fagfellevurdert)
Abstract [en]

Oxidative ageing in bituminous materials is considered to be one of the most important factors for distress types in road applications. The increasing interest in oxidative ageing has highlighted the need for a thorough understanding of the oxidation mechanisms at molecular level. This paper offers some insight in the validity of the proposed hypotheses about the oxidation routes of bitumen, the fast- and the slow-rate route, reflecting on previous studies. Fourier-Transform Infrared (FTIR) and Electron Paramagnetic Resonance (EPR) spectroscopy were utilised for this verification. To elucidate the uncertain formation of sulfoxides, an additional surface investigation with Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) was performed. The findings of the aforementioned techniques reveal the existence of the oxidation products reported previously and contribute to the understanding of the oxidation mechanisms. Overall, this research strengthens experimentally the hypotheses of the dual-oxidation routes of bitumen. © 2022, The Author(s)

sted, utgiver, år, opplag, sider
Springer Science and Business Media B.V., 2022
Serie
RILEM Bookseries, ISSN 2211-0844 ; 27
Emneord
Bitumen, EPR, FTIR, Oxidative ageing, TOF-SIMS
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-59776 (URN)10.1007/978-3-030-46455-4_115 (DOI)2-s2.0-85116492017 (Scopus ID)
Konferanse
-
Tilgjengelig fra: 2022-07-04 Laget: 2022-07-04 Sist oppdatert: 2023-06-05bibliografisk kontrollert
Lu, X., Sjövall, P., Soenen, H., Blom, J. & Makowska, M. (2022). Oxidative aging of bitumen: a structural and chemical investigation. International Journal on Road Materials and Pavement Design, 23(5), 1091-1106
Åpne denne publikasjonen i ny fane eller vindu >>Oxidative aging of bitumen: a structural and chemical investigation
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2022 (engelsk)Inngår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 23, nr 5, s. 1091-1106Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The oxidative aging of bitumen was investigated chemically and structurally using SARA analysis, TOF-SIMS and AFM. Typical wax-containing and non-waxy bitumen samples were selected. Short- and long-term aging tests were conducted under standard conditions, and at prolonged aging times. For both the wax-containing and non-waxy bitumen, aging significantly decreases the aromatic fraction and at the same time increase the content of resins and asphaltenes. AFM shows bee-like structures on the wax-containing bitumen surface, and these structures change when the binder is aged. The bee structures are fewer but larger after a prolonged PAV. For the non-waxy bitumen, no structures were observed, even not after a severe PAV aging that increased the content of asphaltenes significantly. This implies that asphaltenes are most likely not responsible for the formation of bee structures. By TOF-SIMS, the non-waxy bitumen surface did not show structures, neither in the virgin state nor after the severe oxidative aging, further supporting that asphaltenes do not directly result in structure formation. For the wax-containing bitumen, TOF-SIMS shows aliphatics-enriched structures, which generally become larger after oxidative aging.

sted, utgiver, år, opplag, sider
Taylor and Francis Ltd., 2022
Emneord
AFM, Bitumen, oxidative aging, SARA, TOF-SIMS, Asphaltenes, Secondary ion mass spectrometry, Testing, Aromatic fraction, Long-term aging, Most likely, Non-waxy bitumen, Standard conditions, Structure formations, Virgin state, Bituminous materials
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-52023 (URN)10.1080/14680629.2021.1871936 (DOI)2-s2.0-85099411716 (Scopus ID)
Tilgjengelig fra: 2021-01-26 Laget: 2021-01-26 Sist oppdatert: 2023-06-05bibliografisk kontrollert
Heingård, M., Sjövall, P., Schultz, B., Sylvestersen, R. & Lindgren, J. (2022). Preservation and Taphonomy of Fossil Insects from the Earliest Eocene of Denmark. Biology, 11(3), Article ID 395.
Åpne denne publikasjonen i ny fane eller vindu >>Preservation and Taphonomy of Fossil Insects from the Earliest Eocene of Denmark
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2022 (engelsk)Inngår i: Biology, E-ISSN 2079-7737, Vol. 11, nr 3, artikkel-id 395Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Marine sediments of the lowermost Eocene Stolleklint Clay and Fur Formation of north-western Denmark have yielded abundant well-preserved insects. However, despite a long history of research, in-depth information pertaining to preservational modes and taphonomic pathways of these exceptional animal fossils remains scarce. In this paper, we use a combination of scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy (TEM) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) to assess the ultrastructural and molecular composition of three insect fossils: a wasp (Hymenoptera), a damselfly (Odonata) and a pair of beetle elytra (Coleoptera). Our analyses show that all specimens are preserved as organic remnants that originate from the exoskeleton, with the elytra displaying a greater level of morphological fidelity than the other fossils. TEM analysis of the elytra revealed minute features, including a multilayered epicuticle comparable to those nanostructures that generate metallic colors in modern insects. Additionally, ToF-SIMS analyses provided spectral evidence for chemical residues of the pigment eumelanin as part of the cuticular remains. To the best of our knowledge, this is the first occasion where both structural colors and chemical traces of an endogenous pigment have been documented in a single fossil specimen. Overall, our results provide novel insights into the nature of insect body fossils and additionally shed light on exceptionally preserved terrestrial insect faunas found in marine paleoenvironments. © 2022 by the authors.

sted, utgiver, år, opplag, sider
MDPI, 2022
Emneord
Cuticle, Eocene, Fur Formation, Insects, Melanin, Mo-clay, Pigment, Stolleklint Clay, Structural coloration, Ølst Formation
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-58966 (URN)10.3390/biology11030395 (DOI)2-s2.0-85126620965 (Scopus ID)
Merknad

Funding details: Vetenskapsrådet, VR, 2019-03731; Funding text 1: Funding: Financial support for this project was provided by a Distinguished Young Researcher Grant (Grant number 642-2014-3773; Swedish Research Council) to Johan Lindgren and a Project Grant (Grant number 2019-03731; Swedish Research Council) to Peter Sjövall.

Tilgjengelig fra: 2022-03-31 Laget: 2022-03-31 Sist oppdatert: 2023-06-05bibliografisk kontrollert
Lu, X., Soenen, H., Sjövall, P. & Pipintakos, G. (2021). Analysis of asphaltenes and maltenes before and after long-term aging of bitumen. Fuel, 304, Article ID 121426.
Åpne denne publikasjonen i ny fane eller vindu >>Analysis of asphaltenes and maltenes before and after long-term aging of bitumen
2021 (engelsk)Inngår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 304, artikkel-id 121426Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Asphaltenes and maltenes of bitumen before and after aging are investigated by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), time of flight - secondary ion mass spectrometry (TOF-SIMS), and gel permeation chromatography (GPC). It has been shown that bitumen differs in terms of wax. After fractionation, more wax is found in the maltenes compared to the bitumen, and this is even more evident when bitumen is aged. For one bitumen, asphaltenes from the virgin binder do not contain carbonyls, which all fall into the maltenes. After bitumen aging, a large part of the carbonyl and sulfoxide signals is shifted to the asphaltenes. Differences in aromaticity are also evidenced as asphaltenes > bitumen > maltenes. TOF-SIMS shows that maltenes are close to the bitumen, but asphaltenes are more different. Also, maltenes are relatively unaffected by aging while larger differences are found in the asphaltenes between the virgin and aged binders. By GPC, a large molecular weight fraction of bitumen is shown as main part of the asphaltenes. However, asphaltenes also contain low molecular weight molecules that overlap with maltenes. Upon bitumen aging, some low molecular weight compounds may become part of asphaltenes, making the average molecular weight of the asphaltenes lower.

sted, utgiver, år, opplag, sider
Elsevier Ltd, 2021
Emneord
Aging, Asphaltenes, Bitumen, Chemical analysis, Maltenes
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-55468 (URN)10.1016/j.fuel.2021.121426 (DOI)2-s2.0-85110378325 (Scopus ID)
Tilgjengelig fra: 2021-08-06 Laget: 2021-08-06 Sist oppdatert: 2023-06-05bibliografisk kontrollert
Sjövall, P., Bake, K., Pomerantz, A., Lu, X., Mitra-Kirtley, S. & Mullins, O. (2021). Analysis of kerogens and model compounds by time-of-flight secondary ion mass spectrometry (TOF-SIMS). Fuel, 286, Article ID 119373.
Åpne denne publikasjonen i ny fane eller vindu >>Analysis of kerogens and model compounds by time-of-flight secondary ion mass spectrometry (TOF-SIMS)
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2021 (engelsk)Inngår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 286, artikkel-id 119373Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Here, kerogens of differing heat treatments are subjected to extremely high dissociation energies by sample bombardment by 25 keV Bi3+ primary ions during analysis by time-of-flight secondary ion mass spectrometry (TOF-SIMS). Positive and negative secondary ions are produced from this decomposition and fragment ion distributions of model compounds and kerogens are compared and starkly different results are obtained for cations versus anions. Cations exhibit a large range of C/H ratios and include highly unsaturated linear chain ions and aromatic ions. Cations of kerogens possess predominantly no heteroatoms. Positive fragment ion distributions depend on the source material being bombarded. Mature, more aromatic kerogens produce higher yields of fragment ions of highly unsaturated carbon chains while immature, more aliphatic kerogens produce more aromatic fragment ions, particularly at the higher carbon numbers. This is consistent with the observation that aromatic model compounds produce a greater fraction of hydrogen-deficient, carbon chain fragment ions, as compared to a purely aliphatic model compound. There is substantial suppression of free radical fragment cations, except for large fragments. In contrast, there is little free radical suppression of the anions. The anions tend to be very hydrogen deficient, spanning a small range of C/H ratios. Highly unsaturated to pure carbon chain fragment anions dominate while aromatic anions are not found. In both positive and negative ion spectra, the yields of fragment ions corresponding to derivatives of the carbon chain molecules, polyynes and allenes, are substantial. Some heteroatom-containing fragment anions are produced, all of which are very hydrogen deficient. 

sted, utgiver, år, opplag, sider
Elsevier Ltd, 2021
Emneord
Allenes, Aromatic ions, Hydrogen deficient anions, Kerogen maturity, Kerogens, Linear carbon chains, Polyynes, TOF-SIMS
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-50419 (URN)10.1016/j.fuel.2020.119373 (DOI)2-s2.0-85093664613 (Scopus ID)
Tilgjengelig fra: 2020-12-02 Laget: 2020-12-02 Sist oppdatert: 2023-06-05bibliografisk kontrollert
Organisasjoner
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0002-2696-7215
v. 2.41.0