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Boris P Koch - One of the best experts on this subject based on the ideXlab platform.
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fragmentation studies of fulvic acids using collision induced dissociation fourier transform ion cyclotron resonance mass spectrometry
Analytical Chemistry, 2009Co-Authors: Matthias Witt, Jens Fuchser, Boris P KochAbstract:The complex natural organic matter standard Suwannee river fulvic acid (SRFA) was analyzed by negative ion mode electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FTICR MS) using on-resonance collision induced dissociation (CID) of single ultrahigh resolved mass peaks in the ICR cell. Molecular Formula assignment of precursor masses resulted in exactly one Molecular Formula for each of the peaks. Analyses of the corresponding fragment spectra and comparison to different standard substances revealed specific neutral losses and fragmentation patterns which result in structures consisting of a high degree of carboxyl- and fewer hydroxyl groups. The comparison of fragmented mass peaks within different pseudohomologous series (CH2-series, and CH4 vs O exchange) suggested structurally based differences between these series. CID FTICR MS allowed isolating single mass peaks in a very complex natural organic matter spectrum. Subsequently, fragmentation gave structural insights...
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fundamentals of Molecular Formula assignment to ultrahigh resolution mass data of natural organic matter
Analytical Chemistry, 2007Co-Authors: Boris P Koch, Thorsten Dittmar, Matthias Witt, Gerhard KattnerAbstract:Ultrahigh-resolution mass spectrometry via the Fourier transform ion cyclotron resonance technique (FT-ICR-MS) allows the identification of thousands of different Molecular Formulas in natural organic matter and petroleum samples. Molecular Formula assignment from mass data is most critical and time-consuming for these samples, and in many cases, several Formulas can be determined for the same Molecular mass. Therefore, automated procedures are required for an efficient exploitation of the extensive data sets. Here, we revise statements in a recent publication,1 which might result in a misleading impression about our approach of Formula assignment in a previous work. We also summarize and categorize existing procedures for Formula assignment. In addition, we propose new techniques, which are suitable to be implemented in automated evaluation software. The homologous series approach is extended toward a building block approach that can be applied as a new exclusion criterion for incorrect Formula assignmen...
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fundamentals of Molecular Formula assignment to ultrahigh resolution mass data of natural organic matter
Analytical Chemistry, 2007Co-Authors: Boris P Koch, Thorsten Dittmar, Matthias Witt, Gerhard KattnerAbstract:Ultrahigh-resolution mass spectrometry via the Fourier transform ion cyclotron resonance technique (FT-ICR-MS) allows the identification of thousands of different Molecular Formulas in natural organic matter and petroleum samples. Molecular Formula assignment from mass data is most critical and time-consuming for these samples, and in many cases, several Formulas can be determined for the same Molecular mass. Therefore, automated procedures are required for an efficient exploitation of the extensive data sets. Here, we revise statements in a recent publication,1 which might result in a misleading impression about our approach of Formula assignment in a previous work. We also summarize and categorize existing procedures for Formula assignment. In addition, we propose new techniques, which are suitable to be implemented in automated evaluation software. The homologous series approach is extended toward a building block approach that can be applied as a new exclusion criterion for incorrect Formula assignments. The examination of stable isotope ratios of individual molecules in natural organic matter can be applied as an additional and intrinsic evaluation for calculated Molecular Formulas.
Matthias Witt - One of the best experts on this subject based on the ideXlab platform.
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fragmentation studies of fulvic acids using collision induced dissociation fourier transform ion cyclotron resonance mass spectrometry
Analytical Chemistry, 2009Co-Authors: Matthias Witt, Jens Fuchser, Boris P KochAbstract:The complex natural organic matter standard Suwannee river fulvic acid (SRFA) was analyzed by negative ion mode electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FTICR MS) using on-resonance collision induced dissociation (CID) of single ultrahigh resolved mass peaks in the ICR cell. Molecular Formula assignment of precursor masses resulted in exactly one Molecular Formula for each of the peaks. Analyses of the corresponding fragment spectra and comparison to different standard substances revealed specific neutral losses and fragmentation patterns which result in structures consisting of a high degree of carboxyl- and fewer hydroxyl groups. The comparison of fragmented mass peaks within different pseudohomologous series (CH2-series, and CH4 vs O exchange) suggested structurally based differences between these series. CID FTICR MS allowed isolating single mass peaks in a very complex natural organic matter spectrum. Subsequently, fragmentation gave structural insights...
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fundamentals of Molecular Formula assignment to ultrahigh resolution mass data of natural organic matter
Analytical Chemistry, 2007Co-Authors: Boris P Koch, Thorsten Dittmar, Matthias Witt, Gerhard KattnerAbstract:Ultrahigh-resolution mass spectrometry via the Fourier transform ion cyclotron resonance technique (FT-ICR-MS) allows the identification of thousands of different Molecular Formulas in natural organic matter and petroleum samples. Molecular Formula assignment from mass data is most critical and time-consuming for these samples, and in many cases, several Formulas can be determined for the same Molecular mass. Therefore, automated procedures are required for an efficient exploitation of the extensive data sets. Here, we revise statements in a recent publication,1 which might result in a misleading impression about our approach of Formula assignment in a previous work. We also summarize and categorize existing procedures for Formula assignment. In addition, we propose new techniques, which are suitable to be implemented in automated evaluation software. The homologous series approach is extended toward a building block approach that can be applied as a new exclusion criterion for incorrect Formula assignmen...
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fundamentals of Molecular Formula assignment to ultrahigh resolution mass data of natural organic matter
Analytical Chemistry, 2007Co-Authors: Boris P Koch, Thorsten Dittmar, Matthias Witt, Gerhard KattnerAbstract:Ultrahigh-resolution mass spectrometry via the Fourier transform ion cyclotron resonance technique (FT-ICR-MS) allows the identification of thousands of different Molecular Formulas in natural organic matter and petroleum samples. Molecular Formula assignment from mass data is most critical and time-consuming for these samples, and in many cases, several Formulas can be determined for the same Molecular mass. Therefore, automated procedures are required for an efficient exploitation of the extensive data sets. Here, we revise statements in a recent publication,1 which might result in a misleading impression about our approach of Formula assignment in a previous work. We also summarize and categorize existing procedures for Formula assignment. In addition, we propose new techniques, which are suitable to be implemented in automated evaluation software. The homologous series approach is extended toward a building block approach that can be applied as a new exclusion criterion for incorrect Formula assignments. The examination of stable isotope ratios of individual molecules in natural organic matter can be applied as an additional and intrinsic evaluation for calculated Molecular Formulas.
Gerhard Kattner - One of the best experts on this subject based on the ideXlab platform.
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fundamentals of Molecular Formula assignment to ultrahigh resolution mass data of natural organic matter
Analytical Chemistry, 2007Co-Authors: Boris P Koch, Thorsten Dittmar, Matthias Witt, Gerhard KattnerAbstract:Ultrahigh-resolution mass spectrometry via the Fourier transform ion cyclotron resonance technique (FT-ICR-MS) allows the identification of thousands of different Molecular Formulas in natural organic matter and petroleum samples. Molecular Formula assignment from mass data is most critical and time-consuming for these samples, and in many cases, several Formulas can be determined for the same Molecular mass. Therefore, automated procedures are required for an efficient exploitation of the extensive data sets. Here, we revise statements in a recent publication,1 which might result in a misleading impression about our approach of Formula assignment in a previous work. We also summarize and categorize existing procedures for Formula assignment. In addition, we propose new techniques, which are suitable to be implemented in automated evaluation software. The homologous series approach is extended toward a building block approach that can be applied as a new exclusion criterion for incorrect Formula assignmen...
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fundamentals of Molecular Formula assignment to ultrahigh resolution mass data of natural organic matter
Analytical Chemistry, 2007Co-Authors: Boris P Koch, Thorsten Dittmar, Matthias Witt, Gerhard KattnerAbstract:Ultrahigh-resolution mass spectrometry via the Fourier transform ion cyclotron resonance technique (FT-ICR-MS) allows the identification of thousands of different Molecular Formulas in natural organic matter and petroleum samples. Molecular Formula assignment from mass data is most critical and time-consuming for these samples, and in many cases, several Formulas can be determined for the same Molecular mass. Therefore, automated procedures are required for an efficient exploitation of the extensive data sets. Here, we revise statements in a recent publication,1 which might result in a misleading impression about our approach of Formula assignment in a previous work. We also summarize and categorize existing procedures for Formula assignment. In addition, we propose new techniques, which are suitable to be implemented in automated evaluation software. The homologous series approach is extended toward a building block approach that can be applied as a new exclusion criterion for incorrect Formula assignments. The examination of stable isotope ratios of individual molecules in natural organic matter can be applied as an additional and intrinsic evaluation for calculated Molecular Formulas.
Lynn Mazzoleni - One of the best experts on this subject based on the ideXlab platform.
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Molecular Formula composition of β caryophyllene ozonolysis soa formed in humid and dry conditions
Atmospheric Environment, 2017Co-Authors: Shuvashish Kundu, Rebeka Fisseha, Annie L Putman, Thom Rahn, Lynn MazzoleniAbstract:We studied the Molecular Formula composition of six β-caryophyllene SOA samples using ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry under various reaction conditions. The SOA samples were generated in dry or low relative humidity (RH) chamber conditions with or without cyclohexane. All of the studied SOA mass spectra have three distinct clusters of hundreds of negative ions referred to as Group I (100 < m/z < 400), Group II (400 < m/z < 700) and Group III (700 < m/z < 1 000) compounds. C14-16H22-28O2-11, C28-29H42-48O6-16 and C42-43H68-70O14-16 were observed as highly abundant organic compounds in the compound class of Group I, II and III, respectively. The relative intensities of most analytes were higher in humid conditions compared to those in dry conditions, indicating the importance of water-dependent reactions and the catalytic role of water both in the presence and absence of cyclohexane. In addition, Molecular Formulas with higher average carbon numbers were observed in humid SOA than in dry SOA in the absence of cyclohexane, suggesting a decrease of cleavage reactions in humid condition. This study characterizes β-caryophyllene ozonolysis SOA based on ultrahigh mass resolution and demonstrates the significance of humidity in terms of the Molecular distributions and relative abundances of the analytes. We also discuss the possible mechanism for the formation of Group I-III compounds based on the current understanding of SOA formation in the atmosphere.
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atmospheric organic matter in clouds exact masses and Molecular Formula identification using ultrahigh resolution ft icr mass spectrometry
Atmospheric Chemistry and Physics, 2013Co-Authors: Y Zhao, A G Hallar, Lynn MazzoleniAbstract:Abstract. Clouds alter the composition of atmospheric aerosol by acting as a medium for interactions between gas- and particulate-phase substances. To determine the cloud water atmospheric organic matter (AOM) composition and study the cloud processing of aerosols, two samples of supercooled clouds were collected at the Storm Peak Laboratory near Steamboat Springs, Colorado (3220 m a.s.l.). Approximately 3000 Molecular Formulas were assigned to ultrahigh-resolution mass spectra of the samples after using a reversed-phase extraction procedure to isolate the AOM components from the cloud water. Nitrogen-containing compounds (CHNO compounds), sulfur-containing compounds (CHOS and CHNOS compounds) and other oxygen-containing compounds (CHO compounds) with Molecular weights up to 700 Da were observed. Average oxygen-to-carbon ratios of ∼0.6 indicate a slightly more oxidized composition than most water-soluble organic carbon identified in aerosol studies, which may result from aqueous oxidation in the clouds. The AOM composition indicates significant influences from biogenic secondary organic aerosol (SOA) and residential wood combustion. We observed 60% of the cloud water CHO Molecular Formulas to be identical to SOA samples of α-pinene, β-pinene, d-limonene, and β-caryophyllene ozonolysis. CHNO compounds had the highest number frequency and relative abundances and are associated with residential wood combustion and NOx oxidation. Multiple nitrogen atoms in the assigned Molecular Formulas for the nighttime cloud sample composite were observed, indicating the significance of nitrate radical reactions on the AOM composition. Several CHOS and CHNOS compounds with reduced sulfur (in addition to the commonly observed oxidized sulfur-containing compounds) were also observed; however further investigation is needed to determine the origin of the reduced sulfur-containing compounds. Overall, the Molecular composition determined using ultrahigh-resolution Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry provides an unambiguous identification of the cloud water organic anion composition in the Rocky Mountain area that could help to improve the understanding of aqueous-phase processes.
Fei Han - One of the best experts on this subject based on the ideXlab platform.
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a simplified strategy for Molecular Formula determination of chemical constituents in traditional chinese medicines based on accurate mass a 1 and a 2 isotopic peaks using fourier transform ion cyclotron resonance mass spectrometry
Rapid Communications in Mass Spectrometry, 2020Co-Authors: Yu Zhang, Qingyu Zhang, Xue Wang, Xiaowen Chu, Wenwen Sui, Fei HanAbstract:RATIONALE Recently, isotopic fine structures derived from Fourier transform ion cyclotron resonance mass spectrometry have been used to determine the Molecular Formula for unknown compounds in many complex systems. However, a simplified strategy for Molecular Formula determination of chemical constituents in traditional Chinese medicines (TCMs) based on accurate mass, A + 1 and A + 2 isotopic peaks is necessary. METHODS Salviae miltiorrhizae was selected as a representative species. First, the chemical constituents were chromatographically separated and their accurate masses were obtained. The A + 1 and A + 2 isotopic peaks of all chemical constituents were then also acquired. Finally, the chemical Formulae of the chemical constituents were determined. RESULTS In the sample of Salviae miltiorrhizae, the Formulae of 38 CHO-containing chemical constituents were quickly determined, and all chemical constituents were identified using their tandem mass spectrometric data. Moreover, the method was validated by comparison of the A + 1 and A + 2 isotopic peaks, their fragmentation patterns and the retention times of six selected standard substances. CONCLUSIONS The results demonstrate that the described strategy performs well for Molecular Formula determination of chemical constituents in TCMs. This also indicates that this method will be meaningful for the structural identification of chemical constituents of TCMs.