TY  - JOUR
AB  - In the past decade, extensive molecular-level research on asphaltenes, primarily based on mass spectrometric approaches, acknowledged the coexistence of two primary architecture motifs, "island"single-core- and "archipelago"(multi-core)-type structures. Nonetheless, analytical methods for a classification are still limited. In this study, the thermal desorption and pyrolysis behavior of a diverse set of asphaltenes covering island- and archipelago-enriched samples and their extrographic fractions has been investigated by a thermal-optical carbon analyzer (TOCA) hyphenated to high-resolution mass spectrometric evolved gas analysis. The capability of the TOCA for a temperature-resolved quantification of the released carbon is used together with the option of applying an inert or oxidative atmosphere. We found that the relative proportion of organic carbon emitted under an inert atmosphere and below 580 °C (OCdes/pyr) and the organic carbon released at elevated temperatures (>580 °C) and oxidative atmosphere (OCpyrogen) can be used as a classification approach for the prevalent architecture motif. This finding is likely caused by differences in the coking and charring behavior dependent on molecular structure. Hypothetically, single-core constituents will form more resistive shot-like coke due to their larger aromatic cores, whereas multi-core constituents seem to produce easier combustible sponge-like coke. Simultaneously, resonance-enhanced multiphoton ionization (REMPI), a soft ionization scheme particularly selective and sensitive for aromatic constituents, together with Orbitrap Fourier-transform mass spectrometry, allowed for time/temperature-resolved in-depth insights into the evolved chemistry. The alkylation pattern/length of the mass spectra received in OCdes/pyr (480/580 °C) fractions has been identified as a classification measure with lower and more narrow patterns for the asphaltenes dominated by single-core species. However, grouping based on the quantified TOCA results has been significantly more striking. Conclusively, TOCA of asphaltenes and their extrographic fractions can be used for structural classification as well as insights into coprecipitated maltenes, presumably also successfully applicable in future studies on residues from renewable oil sources.
AU  - Rueger, C.P.*
AU  - Neumann, A.*
AU  - Koesling, P.*
AU  - Martinez, S.J.V.*
AU  - Chacón-Patiño, M.L.*
AU  - Rodgers, R.P.*
AU  - Zimmermann, R.
C1  - 66097
C2  - 52647
SP  - 10177–10190
TI  - Addressing thermal behavior and molecular architecture of asphaltenes by a thermal-optical carbon analyzer coupled to high-resolution mass spectrometry.
JO  - Energy Fuels
VL  - 36
IS  - 17
PY  - 2022
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - In the last decades, the production and demand of plastics has drastically increased, with severe environmental impact. Concerning climate change and the idea of a circular economy, waste incineration is not favored and efficient recycling strategies are needed. As one of the most promising approaches, pyrolysis generates a certain amount of solid residue besides liquid and gaseous products. The chemical nature of this char is not fully understood but holds the potential to be used in material science or to generate further chemicals. To explore the value of this feedstock, thermal analysis with mass spectrometric detection of the evolved gas mixture is deployed. With the help of soft photoionization techniques, we were able to identify alkenes, dienes, and polycyclic aromatic hydrocarbons, which were emitted at four distinct mass loss events. Here, resonance-enhanced multiphoton ionization allows selectively addressing of the aromatic constituents, whereas single-photon ionization covered a comprehensive chemical range. Interestingly, we found an enrichment of ultraviolet stabilizers, such as benzophenone, within the macromolecular nature of the residue. The evolved gas mixture was found to be highly complex. Consequently, high-resolution mass spectrometry addressing the isobaric complexity and pyrolysis gas chromatography was used for structural elucidation. We hypothesize island- and archipelago-type structural motives comparable to asphaltenes but with almost no heteroatoms based on analyzing the complex mixture by carbon number versus double bond equivalent cartographies. A comprehensive set of thermal analysis mass spectrometric platforms enabled an in-depth chemical description of plastic pyrolysis char, providing valuable knowledge for reactor design and material science.
AU  - Friederici, L.*
AU  - Schneider, E.*
AU  - Burnens, G.*
AU  - Streibel, T.
AU  - Giusti, P.*
AU  - Rüger, C.P.*
AU  - Zimmermann, R.
C1  - 63017
C2  - 51213
CY  - 1155 16th St, Nw, Washington, Dc 20036 Usa
SP  - 18185-18193
TI  - Comprehensive chemical description of pyrolysis chars from low-density polyethylene by thermal analysis hyphenated to different mass spectrometric approaches.
JO  - Energy Fuels
VL  - 35
IS  - 22
PB  - Amer Chemical Soc
PY  - 2021
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - Coal continues to be a major source of energy for residential heating in some parts of the world due to its low price and good availability. However, only little information on emissions for coal combustion in small-scale appliances, in particular manually-operated stoves, is available. This study investigates the emissions of gases and volatile organic compounds (VOCs) from brown coal briquettes (BCBs) burned in a typical Central European wood stove and compares them to emissions from spruce wood logs. Special emphasis was placed on the evolution of emissions over consecutive batches. In comparison to wood, BCBs made from Lusatian lignite showed higher emissions of compounds that were attributed to the decomposition of lignin, while emissions that were attributed to having originated from pyrosynthesis did not show significant differences between both fuels. Furthermore, a 20-fold higher emission factor for SO2 was obtained from BCB combustion, which is known for its deleterious effect. In addition to a reduction in the carbon footprint, replacing BCBs with logwood as a fuel for residential heating might be beneficial for human health due to vast differences in SO2 emissions, whereas a potential effect from the reduction of organic emissions is questionable due to the rather small differences in organic emissions.
AU  - Martens, P.*
AU  - Czech, H.
AU  - Tissari, J.*
AU  - Ihalainen, M.*
AU  - Suhonen, H.*
AU  - Sklorz, M.
AU  - Jokiniemi, J.*
AU  - Sippula, O.*
AU  - Zimmermann, R.
C1  - 62972
C2  - 51094
CY  - 1155 16th St, Nw, Washington, Dc 20036 Usa
SP  - 14010-14022
TI  - Emissions of gases and volatile organic compounds from residential heating: A comparison of brown coal briquettes and logwood combustion.
JO  - Energy Fuels
VL  - 35
IS  - 17
PB  - Amer Chemical Soc
PY  - 2021
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - Despite extensive research, the molecular-level chemical characterization of asphaltenes, a highly aromatic solubility fraction of petroleum, remains an analytical challenge. This fraction is related to diverse problems in crude oil exploration, transportation, and refining. Two asphaltene architecture motifs are commonly discussed in the literature, “island” (single-core)- and “archipelago” (multicore)-type structures. The thermal desorption and pyrolysis behavior of island- and archipelago-enriched asphaltenes and their extrography fractions was investigated. For this purpose, the evolved chemical pattern was investigated by thermal analysis coupled with ultrahigh-resolution mass spectrometry (Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS)). Soft atmospheric pressure chemical ionization preserved the molecular information of the thermal emission profile. Time-/temperature-resolved analysis allowed the chemical characterization of the occluded material as well as of asphaltene building blocks during pyrolysis. Regarding the thermogravimetric information, the island-type enriched sample (Wyoming asphaltenes) revealed a significantly higher coke residue after the pyrolysis process compared to the archipelago-type enriched sample (Athabasca asphaltenes). In contrast to whole asphaltenes, extrographic fractions revealed that occluded material evolved during the desorption phase. For the acetone fraction, this effect was the most abundant and suggests cooperative aggregation, which persists at high temperatures. Pyrolysis revealed a bimodal behavior for most of the compound classes, suggesting the presence of both architecture motifs in each asphaltene. double-bond equivalent (DBE) vs #C diagrams of the pyrolysis molecular profile revealed specific compositional trends: compounds with high DBE values and short alkylation are likely to be originated from island-type asphaltenes, whereas species with low DBE values and high carbon numbers likely derive from archipelago-type asphaltenes. In the asphaltene structural debate, thermal analysis ultrahigh-resolution mass spectrometry serves as an additional technique and supplements results obtained by other techniques, such as direct infusion approaches. Consistent results on the structural motifs are indicated by the molecular fingerprint visualized by DBE vs #C diagrams and serve as a measure for the dominance of a structural motif.
AU  - Rüger, C.P.*
AU  - Neumann, A.*
AU  - Chacón-Patiño, M.L.*
AU  - Rodgers, R.P.*
AU  - Zimmermann, R.
C1  - 60995
C2  - 49628
CY  - 1155 16th St, Nw, Washington, Dc 20036 Usa
SP  - 3808-3824
TI  - Investigation of island/single-core- And archipelago/multicore-enriched asphaltenes and their solubility fractions by thermal analysis coupled with high-resolution Fourier transform ion cyclotron resonance mass spectrometry.
JO  - Energy Fuels
VL  - 35
IS  - 5
PB  - Amer Chemical Soc
PY  - 2021
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - Modern industry strongly relies on the molecular analysis of fossil petroleum and petroleum-derived materials. In the context of a circular economy and carbon neutrality, the chemical description of alternative feedstock materials, such as waste plastic and biomass pyrolysis oils, increases in importance. Moreover, online monitoring of the thermochemical and catalytic conversion processes has gained rising attention. In this framework, evolved gas analysis (EGA) concepts with soft photoionization mass spectrometry (PIMS) were successfully deployed for numerous challenges. On the one hand, photoionization is a highly versatile technique and allows for "soft"ionization of the analyte molecule, preserving the molecular information. On the other hand, multiple evolved gas analysis concepts exist with unique benefits, such as the mass loss information in thermogravimetry coupling, high-throughput in direct inlet probe concepts, or straightforward reactor monitoring, allowing for direct online insights into pyrolytic transformation processes. Hence, this review aims to summarize the recent work in the field of EGA-PIMS. After technical description of the multiple photoionization and thermal analysis concepts, applied studies are summarized, discussed, and evaluated. Besides fossil fuels, studies on alternatives from renewable materials, such as biomass pyrolysis, plastic pyrolysis oils, and recycling processes, are reviewed. Finally, future perspectives on this field are given, highlighting the importance of those soft ionization schemes together with state-of-the-art detection by high-resolution mass spectrometry in the field of energy and fuels research.
AU  - Rüger, C.P.*
AU  - Tiemann, O.*
AU  - Neumann, A.*
AU  - Streibel, T.
AU  - Zimmermann, R.
C1  - 63552
C2  - 51584
CY  - 1155 16th St, Nw, Washington, Dc 20036 Usa
SP  - 18308–18332
TI  - Review on evolved gas analysis mass spectrometry with soft photoionization for the chemical description of petroleum, petroleum-derived materials, and alternative feedstocks.
JO  - Energy Fuels
VL  - 35
IS  - 22
PB  - Amer Chemical Soc
PY  - 2021
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - Bitumen is a highly viscous and chemically complex petroleum-derived material, which is applied as a binder in road construction. However, the asphalt undergoes hardening, cracking, and embrittlement not only due to oxidative short-term aging during the mixing and paving process but also due to long-term aging during the service time of the pavement. In this study, chemical changes occurring during short-term aging, mimicked by a prolonged rotating flask procedure, are investigated for an artificial bitumen model at the molecular level. The model bitumen enables the application of two complementary analytical techniques for obtaining a comprehensive insight into the aging effects: high-resolution Fourier-transform ion cyclotron mass spectrometry (FT-ICR MS) coupled to thermogravimetry was applied to investigate the aging effects on polar to semipolar high-molecular-weight compounds ionized by atmospheric pressure chemical ionization. Aromatic core structures were analyzed by alternating collision-induced dissociation. In order to support structural assignments from FT-ICR MS data in the semivolatile region, comprehensive two-dimensional gas chromatography mass spectrometry (GC × GC-HRTOFMS) with electron ionization at 70 eV was applied for the group-type analysis and the investigation of particular chemical functionalities. Oxidation processes were revealed to be the prevalent reactions caused by short-term aging of the hydrocarbons (CH-class) and sulfur-containing classes. Aromatic species with low steric hindrance or activated carbon positions as well as high aromatic core structures are favorably oxidized, forming carbonyl functionalities. For molecules with one sulfur atom (S1-class), nonaromatic species such as tetrahydrothiophenes decrease, whereas aromatic S1-compounds remain constant. Nonaromatic S1O1-species tend to further oxidize, while higher aromatic species are formed with ongoing aging time. Moreover, this study highlights the aging behavior of nitrogen-containing compounds, such as carbazoles. A significant reduction of the N-classes was observed during aging, indicating thermal-induced condensation reactions as well as favored oxidation of highly aromatic core structures.
AU  - Neumann, A.*
AU  - Käfer, U.
AU  - Gröger, T.M.
AU  - Wilharm, T.*
AU  - Zimmermann, R.
AU  - Rueger, C.P.*
C1  - 60299
C2  - 49213
CY  - 1155 16th St, Nw, Washington, Dc 20036 Usa
SP  - 10641-10654
TI  - Investigation of aging processes in bitumen at the molecular level with high-resolution fourier-transform ion cyclotron mass spectrometry and two-dimensional gas chromatography mass spectrometry.
JO  - Energy Fuels
VL  - 34
IS  - 9
PB  - Amer Chemical Soc
PY  - 2020
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - Two organic fouling samples obtained from downstream the cracking oven (DS) and from upstream the hot zone (US) of a steam cracker facility were characterized. For this purpose, a simultaneous thermal analyzer coupled to a photoionization mass spectrometer (STA-PI-MS) and a thermal desorption/pyrolysis gas chromatograph (TD/Py-GC-EI-MS) were used. Mass loss and differential scanning calorimetry information revealed the degradation of the materials beginning at 130 degrees C with two distinct maxima for US and one for DS (230-330 degrees C) as well as broad signals (330-500 degrees C) for both. Structural motives of different polymeric-like structures were assigned based on PI-MS of the effluent and separately conducted TD/Py-GC-EI-MS. The advantage of soft photoionization over hard ionization techniques such as electron ionization is the considerable reduction of fragmentation, yielding higher abundancies of molecular ions. Thus, even though complex samples are studied, evolving constituents can often be easily tracked in a time-resolved manner (1 Hz). While single photon ionization (SPI, 118 nm = 10.5 eV) ionizes most organic molecules, resonance-enhanced multiphoton ionization (REMPI, 2 x 266 nm = 9.4 eV) selectively addresses aromatic species. Differentiation of polymeric-like structures was achieved by exploiting this selectivity (SPI vs REMPI) and comparison of molecular patterns with GC-EI-MS data, which supports the identification of compounds by providing fragmentation patterns and chemical information based on retention time. US shows high inorganic content (similar to 50%) and more diversity in its organic part, as indicated by four types of patterns: polyethylene-like, Diels-Alder-like polythioether/polysulfide-like, and polystyrene-like motives. In contrast, DS exhibits almost only signals of Diels-Alder-like and polystyrene-like structures and contains a less inorganic material (similar to 23%). Additionally, first attempts to quantify the Diels-Alder content by STA-SPI-MS were successfully conducted.
AU  - Grimmer, C.*
AU  - Rüger, C.P.*
AU  - Streibel, T.
AU  - Cuoq, F.*
AU  - Kwakkenbos, G.*
AU  - Cordova, M.*
AU  - Peñalver, R.*
AU  - Zimmermann, R.
C1  - 57312
C2  - 47703
CY  - 1155 16th St, Nw, Washington, Dc 20036 Usa
SP  - 11592-11602
TI  - Description of steam cracker fouling and coking residues by thermal analysis-photoionization mass spectrometry.
JO  - Energy Fuels
VL  - 33
IS  - 11
PB  - Amer Chemical Soc
PY  - 2019
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - On January 1, 2020, new International Maritime Organization (IMO) legislation will reduce the maximum sulfur content for marine fuels outside of sulfur emission control areas (SECA) from now 3.50% (m/m) to 0.50% (m/m) to lower the emission of SOx. In order to enable a smooth transition to the new-generation fuels and to cope with a widely diversified spectrum of heavy fuel oils, a comprehensive chemical description of such bunker fuels will become more important to investigate differences which may cause incompatibility with current engines or to avoid a negative impact for the storage stability. Comprehensive two-dimensional gas chromatography with mass-spectrometric detection (GC X GC-MS) has become one of the most potent analytical methods for detailed analysis of hydrocarbon composition in complex petroleum fractions. However, matrices that contain significant amounts of less- or nonvolatile constituents, such as marine fuels, cannot entirely be targeted by gas chromatography alone. In order to extend the application range of a GC X GC high-resolution time-of-flight mass spectrometry platform (GC X GC-HRTOFMS), we applied and compared thermogravimetric analysis (TGA-HRTOFMS) and direct inlet probe (DIP-HRTOFMS) as additional thermal sample introduction techniques. In this study, we investigated five different marine fuels with GC x GC-, DIP-, and TGA-HRTOFMS to analyze volatile as well as residual compounds. Since each of the deployed techniques showed unique advantages and possibilities, the complementarity of the combined approach is demonstrated. The combination of GC x GC-, DIP-, and TGA-HRTOFMS data enabled the generation of comprehensive chemical fingerprints for differentiation and chemical classification.
AU  - Käfer, U.
AU  - Gröger, T.M.
AU  - Rohbogner, C.J.*
AU  - Struckmeier, D.*
AU  - Saraji-Bozorgzad, M.R.*
AU  - Wilharm, T.*
AU  - Zimmermann, R.
C1  - 57142
C2  - 47554
CY  - 1155 16th St, Nw, Washington, Dc 20036 Usa
SP  - 10745-10755
TI  - Detailed chemical characterization of bunker fuels by high-resolution time-of-flight mass spectrometry hyphenated to GC×GC and thermal analysis.
JO  - Energy Fuels
VL  - 33
IS  - 11
PB  - Amer Chemical Soc
PY  - 2019
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - Bitumen is a widely used material, but its aging behavior is only understood at a macroscopic level as hardening and embrittlement over time. To assess bitumen aging behavior in the long run, the pressure aging vessel (PAV) testing procedure was developed. However, this procedure including high-pressure and high-temperature oxidation of the bitumen has not yet been understood on a molecular level. Here, a bitumen sample and its SARA fractions, i.e., saturates, aromatics, resins, and asphaltenes, were investigated in comparison with their aged samples to study changes of their chemical compositions. Negative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry [ESI(-)] FT-ICR-MS was used to analyze samples. The effect of aging was characterized using the aromaticity equivalent (X-c, double bond equivalent (DBE), and van Krevelen plots. It was found that aging induces reduction of condensed aromatic compounds to alicyclic and open chain aliphatic compounds, while small aromatic compounds have been found to be relatively stable (or altered only slightly). Abundant alterations were detected in unaged bitumen. These changes can be assigned to resins and asphaltenes as compared to saturates and aromatics. Overall, alterations of highly condensed compounds were found to be related to aging. Furthermore, molecular series of CHO, CHNO, and CHOS fragments were more susceptible to oxygenation in bitumen, aromatics, resins, and asphaltenes as compared to saturates. In addition, molecular changes in asphaltenes showed a significant difference from classical assessment with high content of condensed aromatic compounds. Rather, the most abundant compounds in asphaltenes appear to be more saturated and apolar.
AU  - Handle, F.*
AU  - Harir, M.
AU  - Fuessl, J.*
AU  - Kosyun, A.N.*
AU  - Grossegger, D.*
AU  - Hertkorn, N.
AU  - Eberhardsteiner, L.*
AU  - Hofko, B.*
AU  - Hospodka, M.*
AU  - Blab, R.*
AU  - Schmitt-Kopplin, P.
AU  - Grothe, H.*
C1  - 51309
C2  - 42953
CY  - Washington
SP  - 4771-4779
TI  - Tracking aging of bitumen and its saturate, aromatic, resin, and asphaltene fractions using high-field fourier transform ion cyclotron resonance mass spectrometry.
JO  - Energy Fuels
VL  - 31
IS  - 5
PB  - Amer Chemical Soc
PY  - 2017
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - In this work, a reversed-phase high-temperature comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOFMS) approach for the qualitative and quantitative analyses of crude oils will be presented. The proposed setup provides the best utilization of the two-dimensional separation space for carbon numbers between C 10 and C 60 . Visual Basic Script (VBS) was successfully applied for data processing to achieve comprehensive classification of the main compound classes. On this basis, crude oils from different origins could be compared by their composition. Real distillation cuts following ASTM D2892 and ASTM D5236 were applied for the development of area-based templates representing virtual boiling point cuts. By this approach, a quantification of an artificial crude oil sample with a defined initial boiling point was evaluated versus the quantitative result according to ASTM D7169 (one-dimensional simulated distillation for high boiling samples, hereinafter 1D-SimDist), and by this, a two-dimensional simulated distillation (2D-SimDist) was successfully developed.
AU  - Jennerwein, M.
AU  - Eschner, M.S.*
AU  - Wilharm, T.*
AU  - Zimmermann, R.
AU  - Gröger, T.M.
C1  - 52462
C2  - 43990
CY  - Washington
SP  - 11651-11659
TI  - Proof of concept of high-temperature comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry for two-dimensional simulated distillation of crude oils.
JO  - Energy Fuels
VL  - 31
IS  - 11
PB  - Amer Chemical Soc
PY  - 2017
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - Thermal desorption and pyrolysis of various heavy oils and asphaltenes (precipitated with different paraffinic solvents) were studied. For this purpose evolved gas analysis was realized by hyphenation of a thermobalance to ultrahigh-resolution mass spectrometry (FT-ICR MS). The chemical pattern was preserved by applying soft atmospheric pressure chemical ionization (APCI). Collision induced dissociation (CID) was performed for deeper structural insights. Viscous or solid petroleum samples and fractions can be easily measured by the setup. The SARA fractions (maltenes, C7-asphaltenes, aromatics, saturated, and resins), deployed for evaluation purposes, revealed a very complex molecular pattern, and fractionation drastically increased the number of assigned elemental compositions. Species from m/z 150 to m/z 700 and two main phases (desorption and pyrolysis), which transits at roughly 300-350 °C, are observed. Both phases overlap partially but can be separated by applying matrix factorization. The heavy oil and asphaltene mass spectra are dominated by CH-, CHS-, and CHN-class compounds, whereas for the CID spectra a lower abundance of oxygenated species was found. Furthermore, physicochemical properties and the molecular response were correlated for the heavy oils and asphaltene samples, finding a strong correlation between sulfur content and abundance of CHS x -class compounds as well as between double bond equivalent (DBE) and API gravity. As the CID leads mainly to dealkylation, the length of alkylated side chains of components evolved thermally or by pyrolytic processes can be traced during the temperature ramp. In general, an increase of dealkylation in the desorption phase, followed by a decrease during the transition to pyrolysis and an increase reaching a stable plateau for stable pyrolysis, was detected. This behavior was found to be similar for all asphaltenes and for the mean DBE progression. Deploying a lighter paraffinic solvent for asphaltene precipitation causes a higher abundance of species emitted in the desorption phase. They belong mainly to CHO x -class compounds from the maltene fraction occluded and coprecipitated with the asphaltenes. Besides this, no significant effect of the precipitation solvent on the asphaltenic core structures and molecular pattern in the pyrolysis phase was observed. The DBE distribution sug gests the presence of the archipelago asphaltene molecular architecture.
AU  - Rüger, C.P.*
AU  - Neumann, A.*
AU  - Sklorz, M.
AU  - Schwemer, T.*
AU  - Zimmermann, R.
C1  - 52659
C2  - 44090
CY  - Washington
SP  - 13144-13158
TI  - Thermal analysis coupled to ultrahigh resolution mass spectrometry with collision induced dissociation for complex petroleum samples: Heavy oil composition and asphaltene precipitation effects.
JO  - Energy Fuels
VL  - 31
IS  - 12
PB  - Amer Chemical Soc
PY  - 2017
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - In this study, the asphaltene and corresponding crude oil, distributed within the Asphaltene Characterization Interlaboratory Study for PetroPhase 2017, were characterized on the molecular level. For this purpose, three different thermal analysis mass spectrometry hyphenations with five diverse ionization techniques varying in selectivity were deployed: (1) thermal desorption/pyrolysis gas chromatography electron ionization (TD/Pyr-GC-EI-QMS), (2/3) thermogravimetry singlephoton/resonance-enhanced multiphoton ionization time-of-flight (TG SPI/REMPI TOF-MS), and (4/5) thermogravimetry atmospheric pressure photo-/chemical ionization ultrahigh-resolution mass spectrometry (TG APPI/APCI FT-ICR MS). For the investigated C-7 asphaltene, no mass loss was detected at <300 degrees C and the pyrolysis phase was dominant, whereas the parent crude oil exhibits a high abundant desorption phase. At roughly 330 degrees C, pyrolysis begins and mass loss as well as complex mass spectrometric patterns were recorded. The resulting information on the effluent gained by the different soft ionization mass spectrometric approaches was combined with the GC-EI-MS data for structural cross-evaluation. We showed that the combination of the applied techniques leads to a more comprehensive chemical characterization. For the asphaltene, TG SPI TOF-MS shows high abundances of alkanes, alkenes, and hydrogen sulfide during pyrolysis. TG REMPI TOF-MS is selective toward aromatics and reveals clear patterns of polyaromatic hydrocarbons (PAHs) and minor amounts of nitrogen-containing aromatics tentatively identified as acridine-or carbazol-like structures. GC-EI-MS provides information on the average chain length of alkanes, alkenes, and PA(S)H. Both atmospheric pressure ionization techniques (APPI and APCI) hyphenated to FT-MS showed CHS (in particular, benzothiophenes) and CH as dominant compound classes, with an average number of condensed aromatic rings of 2-4. Combining the information of all techniques, including the average asphaltene mass obtained by field desorption experiments and aromatic core size received by collision-induced dissociation, the archipelago-type molecular structure seems to be dominant for the investigated asphaltene.
AU  - Rüger, C.P.*
AU  - Grimmer, C.*
AU  - Sklorz, M.*
AU  - Neumann, A.*
AU  - Streibel, T.
AU  - Zimmermann, R.
C1  - 53023
C2  - 44275
CY  - Washington
SP  - 2699-2711
TI  - Combination of different thermal analysis methods coupled to mass spectrometry for the analysis of asphaltenes and their parent crude oils: Comprehensive characterization of the molecular pyrolysis pattern.
JO  - Energy Fuels
VL  - 32
IS  - 3
PB  - Amer Chemical Soc
PY  - 2017
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - Pyrolysis or liquefaction processes can be applied to lignocellulosic biomass to produce a bio-oil which allows the access of green chemicals or sustainable energy. Among the different existing resources, this raw material has the advantage to come from nonfood feedstocks such as agricultural wastes (wood, grass, ...) or dedicated plantations. Whatever the considered bio-oil, the development of high performance analytical techniques is needed to achieve an exhaustive characterization. The use of Fourier transform ion cyclotron resonance mass spectrometry coupled to electrospray ionization (ESI-FT-ICR-MS) has the potential to chemically identify the components of bio-oil at the level of the molecular formula. In this work, we investigated the influence of the sample preparation (use and nature of dopant and ion detection mode) on the development of a robust methodology for lignocellulosic based bio-oil characterization. Commonly used ESI dopants have been studied to increase the ionization yield and the measurement repeatability. We highlighted the dramatic effect of the sample preparation on the global chemical description of the bio-oil, especially the disproportional contribution of the CxHyN1–5Oz species. Moreover, we demonstrated the ability of well-controlled ESI ionization conditions to attain, on the one hand, specific chemical information on the origin (cellulose, hemicellulose, or lignin) of the bio-oil constituents and, on the other hand, the simultaneous description of both its oily and aqueous compounds without a fractionation step.
AU  - Hertzog, J.*
AU  - Carré, V.*
AU  - le Brech, Y.*
AU  - Dufour, A.*
AU  - Aubriet, F.*
C1  - 54678
C2  - 0
SP  - 5729-5739
TI  - Toward controlled ionization conditions for ESI-FT-ICR-MS analysis of bio-oils from lignocellulosic material.
JO  - Energy Fuels
VL  - 30
IS  - 7
PY  - 2016
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - The online analysis of volatiles from biomass pyrolysis (or gasification or combustion) is interesting because it has the ability to sample the volatiles directly from their reactive environment. The photon ionization (PI) is an efficient and soft ionization method for online analysis of biomass pyrolysis volatiles. Here, we review recent developments conducted in our groups on PI-mass spectrometry (MS) analysis of biomass pyrolysis volatiles by (1) synchrotron light PI MS and (2) various commercial PI-MS techniques combined with various pyrolysis reactors. The fundamentals of PI MS applied to biomass tar are briefly presented. The effect of photon energy on mass spectra from biomass volatiles is studied by synchrotron PI-MS. Different sources of PI-MS are then compared on vapors produced from fast pyrolysis in a microfluidized bed, namely, argon electron-beam-pumped excimer light (EBEL) vacuum ultraviolet (VUV) lamp single photon ionization (SPI)-MS (126 nm and 9.8 eV), laser Xe cell-SPI-MS (118 nm and 10.5 eV), laser resonance-enhanced multiphoton ionization (REMPI)-MS (266 nm). The suitability of these different ionization techniques for tar online analysis is discussed. The high potential of PI-MS to unravel the mechanisms of biomass pyrolysis is highlighted by some examples of applications. A VUV lamp SPI-MS has been combined to a fixed bed reactor to study the evolution of chemical markers from lignin, cellulose, and hemicelluloses as functions of biomass types and temperature of pyrolysis. It has also been combined to a microfluidized bed to study the fast pyrolysis of different sizes, shapes, and composition of biomass particles. Principal component analysis of the various MS "fingerprints" reveals interesting markers of some pyrolysis regimes.
AU  - Jia, L.*
AU  - le Brech, Y.*
AU  - Mauviel, G.*
AU  - Qi, F.*
AU  - Bente-von Frowein, M.*
AU  - Ehlert, S.
AU  - Zimmermann, R.
AU  - Dufour, A.*
C1  - 48403
C2  - 41069
CY  - Washington
SP  - 1555-1563
TI  - Online analysis of biomass pyrolysis tar by photoionization mass spectrometry.
JO  - Energy Fuels
VL  - 30
IS  - 3
PB  - Amer Chemical Soc
PY  - 2016
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - The real-time analysis of volatiles (primary tar) produced during the fast pyrolysis of biomass in a microfluidized bed reactor (MFBR) is achieved by online single photoionization mass spectrometry (SPI-MS). The effect of biomass composition (Douglas fir, oak, and miscanthus), particle shape and size (cylinder, lamella, or powder), bed temperature, and fluidizing gas flow-rate on primary tar composition is studied. Principle component analysis is conducted on the major ions analyzed by SPI-MS to evidence the significant differences between conditions. The variance in obtained SPI-MS spectra reveals the important effect of biomass composition and temperature on volatiles composition. The effect of particle size on volatiles composition is clearly evidenced. Typical pyrolysis regimes are defined according to specific markers which are key chemical compounds to characterize biomass fast pyrolysis. SPI-MS combined with a MFBR is an interesting tool to unravel the effects of biomass composition and of heat and mass transfers on biomass fast pyrolysis processes.
AU  - Jia, L.*
AU  - Le-Brech, Y.*
AU  - Shrestha, B.*
AU  - Bente-von Frowein, M.*
AU  - Ehlert, S.
AU  - Mauviel, G.*
AU  - Zimmermann, R.
AU  - Dufour, A.*
C1  - 49490
C2  - 31677
SP  - 7364-7374
TI  - Fast pyrolysis in a microfluidized bed reactor: Effect of biomass properties and operating conditions on volatiles composition as analyzed by online single photoionization mass spectrometry.
JO  - Energy Fuels
VL  - 29
IS  - 11
PY  - 2015
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - Increasing reports about malfunctions in common rail injector (CRI) systems lead to a more intensive research on diesel fuel injection systems, which are working under higher pressures and temperatures. Under these conditions, deposits were formed and deteriorated the injector performance. Therefore, it is necessary to investigate the formed deposits to avoid injector sticking. Previous studies have identified different substance classes, such as alkanes, carboxylic salts, and aromatic hydrocarbons in the deposits. In particular, aromatics and polycyclic aromatic hydrocarbons (PAHs) are suspected to produce insoluble solid precipitates. In this study, thermodesorption resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (REMPI-ToF-MS) as a novel analytical technique for direct measurements of aromatic-containing deposits on injector parts was performed. Experiments were carried out in a self-made test bench, where the CRI were installed. The influence of the temperature, injection pressure, injection amount of used fuel, and fuel composition on the tendency to form deposits on the metal surface of commercial CRI parts, especially its ring, was investigated. In most cases, the rings were directly analyzed by the aromatic-selective REMPI technique without any sample preparation. The temperature program of the used carbon analyzer (CA) helps to separate the desorbing material into volatile and non-volatile organic matter during the pyrolysis under a helium atmosphere within the oven of the CA. The results concentrate on the volatile organic matter desorbing step and indicate a strong influence of the temperature and fuel composition on the amount of analyzed aromatic compounds. They were not equal, with the results of thickness layer measurements in individual cases. Comprehensive analytical methods, such as single photon ionization (SPI), are needed for further information.
AU  - Lau, K.*
AU  - Junk, R.*
AU  - Klingbeil, S.*
AU  - Schümann, U.*
AU  - Streibel, T.
C1  - 46884
C2  - 39017
SP  - 5625-5632
TI  - Analysis of internal common rail injector deposits via thermodesorption photon ionization time of flight mass spectrometry.
JO  - Energy Fuels
VL  - 29
IS  - 9
PY  - 2015
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - Gas-phase emission samples of carbonyl compounds (CCs) were collected from two modern wood combustion appliances. Multiple repetitions were conducted on masonry heater operated with three logwood species (birch, beech, and spruce) and for a pellet boiler operated by softwood pellet with normal combustion and unoptimized combustion (in which the secondary combustion air flow rate was decreased). The sampling of CCs was performed from diluted exhaust using 2,4-dinitrophenylhydrazine (DNPH) cartridges. The CCs-hydrazone derivatives were analyzed by a gas chromatography–selective ion monitoring–mass spectrometry (GC-SIM-MS) method. Twelve (12) CCs were quantified in the masonry heater emissions and 8 in the pellet boiler emissions. The total carbonyl emission factors (EFs) for logwood were determined to be as follows: birch, 113 ± 18 mg kg–1; beech, 178 ± 31 mg kg–1; spruce, 171 ± 19 mg kg–1; and, for softwood pellet with normal combustion, 6 ± 0.9 mg kg–1 and for softwood pellet with unoptimized combustion, 6.5 ± 1 mg kg–1. In masonry heater operation, birch exhibits the lowest emission factors, compared to other wood types. No significant differences were noticed between the emission of normal and unoptimized combustion for the pellet boiler operation. The emission profile examination showed that formaldehyde and acetaldehyde were the predominated carbonyls in the emission, regardless of the wood type. Time-resolved results obtained via single-photon ionization time-of-flight mass spectrometry (SPI-TOFMS) depict that, in masonry heater emissions, most carbonyls are produced as a new batch of wood is introduced.
AU  - Reda, A.
AU  - Czech, H.*
AU  - Schnelle-Kreis, J.
AU  - Sippula, O.*
AU  - Orasche, J.
AU  - Weggler, B.A.
AU  - Abbaszade, G.
AU  - Arteaga-Salas, J.M.
AU  - Kortelainen, M.*
AU  - Tissari, J.*
AU  - Jokiniemi, J.*
AU  - Streibel, T.
AU  - Zimmermann, R.
C1  - 45247
C2  - 37267
CY  - Washington
SP  - 3897-3907
TI  - Analysis of gas-phase carbonyl compounds in emissions from modern wood combustion appliances: Influence of wood type and combustion appliance.
JO  - Energy Fuels
VL  - 29
IS  - 6
PB  - Amer Chemical Soc
PY  - 2015
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - The trace polar species present in diesel were investigated by combining selective ionization with high-resolution mass spectrometry. To eliminate matrix effects, the polar fraction was extracted using methanol and direct infusion with electrospray ionization and mass analysis were performed. The advantages and limitations of time-of-flight mass spectrometry and Fourier transform ion cyclotron resonance mass spectrometry for diesel analysis were discussed. Complementary information was obtained by considering both positive- and negative-ion mass spectra in terms of compounds that form part of the inherent fuel composition and compounds that represent fuel additives. In addition, diluted fuels were separated by gas chromatography prior to atmospheric pressure chemical ionization and mass analysis. Results showed that a large portion of unsaturated polycyclic hydrocarbons were not detected during direct infusion experiments, indicating that these species were not extracted efficiently with methanol and/or ionized efficiently with electrospray.
AU  - Smit, E.*
AU  - Rüger, C.P.*
AU  - Sklorz, M.
AU  - de Goede, S.*
AU  - Zimmermann, R.
AU  - Rohwer, E.R.*
C1  - 46885
C2  - 39016
SP  - 5554-5562
TI  - Investigating the trace polar species present in diesel using high-resolution mass spectrometry and selective ionization techniques.
JO  - Energy Fuels
VL  - 29
IS  - 9
PY  - 2015
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - The subject of the presented work was the development of a two-dimensional GCxGC time-of-flight mass spectrometric method (GCxGC-TOFMS) for the complete group-type quantification of petroleum middle distillates. The development of this method was possible due to the inherent features of GCxGC-TOFMS, namely the structured arrangement of compound groups and the mass fragmentation pattern, which provide the possibility of using Visual Basic Scripts as an analytical tool and thereby the classification of several thousand different compounds. The analysis method was focused on common petroleum based fuels from light to heavier middle distillation fractions. For the implementation of an absolute quantification method, a set of standard substances representing the main substance classes and carbon numbers within middle distillates and well-separated and recognizable internal standards were thoroughly chosen in order to obtain individual response factors and group specific response curves. The results of the qualitative and quantitative analysis were compared to well-established standard methods used in the petrochemical industry. The quantification of aromatic hydrocarbons was compared to EN 12916, a high performance liquid chromatography (HPLC) method that provides a rough separation between mono-, di-, and higher aromatics. Further, the quantification of the fatty acid methyl ester (FAME) content in diesel fuel was compared to EN 14078 and the distribution of single FAMEs was compared to EN 14103. It could be stated that an absolute quantification as the here presented method has not been reported before and the results were in good agreement with the reference methods. Furthermore, the here presented GCxGC-TOFMS quantification method is able to itemize according substance classes and carbon number. The detection limit of the method allows accurate and sensitive quantification for different limiting values of middle distillates with a single method.
AU  - Jennerwein, M.
AU  - Eschner, M.*
AU  - Gröger, T.M.
AU  - Wilharm, T.*
AU  - Zimmermann, R.
C1  - 32566
C2  - 35230
SP  - 5670-5681
TI  - Complete group-type quantification of petroleum middle distillates based on comprehensive two-dimensional Gas Chromatography Time-of-Flight Mass Spectrometry (GCxGC-TOFMS) and visual basic scripting.
JO  - Energy Fuels
VL  - 28
IS  - 9
PY  - 2014
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - The presented wood combustion emission study employing a logwood stove showed that four burning phases of different aerosol compositions and different amounts of emitted particulate matter (PM) occurred during a combustion batch. As a novel approach, in this study, the burning phases were defined by chemical changes in the aerosol gas phase during combustion, instead of being linked to predefined time periods or the amount of PM emissions. This deeper view into the aerosol chemistry of the different burning phases was possible by employing online mass spectrometry techniques with high time resolution. A special soft ionization technique enabled the selective detection of polyaromatic hydrocarbons (PAHs) in the gas phase, whereas changes in the particle phase were observed by aerosol mass spectrometer (AMS). The use of AMS allowed the description of changes in the particle phase and in the amounts of PM emitted during the burning phases, as well as verification of the observed burning phases. Finally, it was shown that the organic fraction and the amount of particles emitted during the ignition phase were main contributors to the emitted PM. The definition of these four burning phases was supported by a more detailed investigation of the chemistry of the organic matter using a Van Krevelen description (average H/C ratios of 1.32-1.64 and O/C ratios of 0.25-0.44, with individual values up to 1.4) along with our novel approach of employing positive matrix factorization (PMF) as a source apportionment tool for the separation of one emission source into different combustion-dominated processes. In addition, the highly dynamic and complex nature of wood combustion emissions was revealed by these analysis methods. It was shown that different combustion conditions have a strong impact on the amount of emitted PM. For instance, an experiment with an overloaded stove emitted a roughly 4-fold higher mass of PM compared to a stove run under the manufacturer's recommended (normal) combustion conditions. This experiment showed a much higher amount of PAHs, which are very harmful for human health.
AU  - Elsasser, M.
AU  - Busch, C.*
AU  - Orasche, J.
AU  - Schön, C.*
AU  - Hartmann, H.*
AU  - Schnelle-Kreis, J.
AU  - Zimmermann, R.
C1  - 27200
C2  - 32575
SP  - 4959-4968
TI  - Dynamic changes of the aerosol composition and concentration during different burning phases of wood combustion.
JO  - Energy Fuels
VL  - 27
IS  - 8
PB  - Amer. Chemical Soc.
PY  - 2013
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - The impact of combustion conditions on emission factors and characteristics of log wood combustion was investigated. Two different kinds of log woods (spruce and beech) and one kind of briquette (spruce sawdust) were used to study differences in emission behavior depending upon the wood type. Beech wood was used to examine additionally the impact of different moisture contents and maloperation on emissions of fine particulate matter (PM). Therefore, wood logs with three different levels of moisture content were used. Maloperation was simulated by an overload scenario and an air deficiency scenario. Toxicity equivalent (TEQ) values were calculated for the different combustion conditions. It was found that PM mass varies only by a factor of 8 at a maximum, whereas TEQ values can vary more than a factor of 80 (regular beech wood combustion, 6 μg MJ–1; beech wood combustion in an overloaded combustion chamber, 500 μg MJ–1). In particular, wood with a higher moisture content (19%) released high amounts of intermediate products from lignin and cellulose degradation. The PM emissions in this case were the highest among the tested operation conditions, especially during the initial (cold start) inflaming (660 μg MJ–1), but were not in correspondence with the toxicity potential. The TEQ (37 μg MJ–1) in that case was much lower than during maloperation.
AU  - Orasche, J.
AU  - Schnelle-Kreis, J.
AU  - Schön, C.*
AU  - Hartmann, H.*
AU  - Ruppert, H.*
AU  - Arteaga-Salas, J.M.
AU  - Zimmermann, R.
C1  - 23676
C2  - 31228
SP  - 1482-1491
TI  - Comparison of emissions from wood combustion. Part 2: Impact of combustion conditions on emission factors and characteristics of particle-bound organic species and Polycyclic Aromatic Hydrocarbon (PAH)-related toxicological potential.
JO  - Energy Fuels
VL  - 27
IS  - 3
PB  - American Chemical Society
PY  - 2013
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - In the current discussion about future energy and fuel supply based on regenerative energy sources, the so-called second-generation biofuels represent a vitally important contribution for the provision of carbon-based fuels. In this framework, at the Karlsruhe Institute of Technology (KIT), the bioliq process has been developed, by which biomass is flash-pyrolyzed at 500 degrees C for the production of so-called biosyncrude, a suspension of the pyrolysis liquids and the remaining biochar. However, little is known about the composition of the pyrolysis gases in this process with regard to different biomass feedstock and process conditions, and the influence on the subsequent steps, namely, the gasification and subsequent production of biofuels or base materials. Time-of-flight mass spectrometry (TOFMS) with two soft (i.e., fragmentation free) photoionization techniques was for the first time applied for on-line monitoring of the signature organic compounds in highly complex pyrolysis gases at a technical pyrolysis pilot plant at the KIT. Resonance-enhanced multiphoton ionization with TOFMS using UV laser pulses was used for selective and sensitive detection of aromatic species. Furthermore, single-photon ionization using VUV light supplied by an electron beam-pumped excimer light source was used to comprehensively ionize (nearly) all organic molecules. For the miscellaneous biomass feeds used, distinguishable mass spectra with specific patterns could be obtained, mainly exhibiting typical pyrolytic decomposition products of (hemi)cellulose and lignin (phenol derivatives), and nitrogen-containing compounds in some cases. Certain biomasses are differentiated by their ratios of specific groups of phenolic decomposition products. Therefore, principal component and cluster analysis describes the varied pyrolysis gas composition for temperature variations and particularly for different biomass species. The results can be integrated in the optimization of the bioliq process.
AU  - Fendt, A.
AU  - Streibel, T.
AU  - Sklorz, M.
AU  - Richter, D.*
AU  - Dahmen, N.*
AU  - Zimmermann, R.
C1  - 7193
C2  - 29538
SP  - 701-711
TI  - On-line process analysis of biomass flash pyrolysis gases enabled by soft photoionization mass spectrometry.
JO  - Energy Fuels
VL  - 26
IS  - 1
PB  - Amer. Chemical Soc.
PY  - 2012
SN  - 0887-0624
ER  - 

TY  - JOUR
AB  - An investigation was performed to study the emissions of state of the art Small-scale residential heating appliances. The different combustion systems Were compared at optimal combustion conditions. A comprehensive characterization of released organic species of all combustion systems was performed. An approach Was performed to estimate the toxicity of the emitted particulate matter by the content of polycyclic aromatic hydrocarbons (PAHs). It is based on the proposal of the German Research Foundation (DFG) that the health risk is proportionally summarized by different PAHs with different health risk potentials. This approach allows for a rough but fast comparison of different furnaces by the Calculation of the toxic equivalent (TEQ) value in addition to the emission of particulate matter (pm). Best results Were obtained by combusting wood as pellets in a modern pellet boiler (PM = 11-13 mg MJ(-1) and TEQ = 0:12-0.75 mu g MJ(-1)). On the opposite of the emission scale, the toxic potentials of the typical log wood stave were found to be about 2 orders of higher (pm = 67-119 mg MJ(-1) and TEQ = 14-28 mu g MJ(-1)) compared to the pellet boiler, despite optimized combustion conditions.
AU  - Orasche, J.
AU  - Seidel, T.*
AU  - Hartmann, H.*
AU  - Schnelle-Kreis, J.
AU  - Chow, J.C.*
AU  - Ruppert, H.*
AU  - Zimmermann, R.
C1  - 11493
C2  - 30744
SP  - 6695-6704
TI  - Comparison of emissions from wood combustion. Part 1: Emission factors and characteristics from different small-scale residential heating appliances considering particulate matter and Polycyclic Aromatic Hydrocarbon (PAH)-related toxicological potential of particle-bound organic species.
JO  - Energy Fuels
VL  - 26
IS  - 11
PB  - American Chemical Society
PY  - 2012
SN  - 0887-0624
ER  -