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Thorsten Reemtsma - One of the best experts on this subject based on the ideXlab platform.
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differences in the molecular composition of Fulvic acid size fractions detected by size exclusion chromatography on line fourier transform ion cyclotron resonance fticr mass spectrometry
Water Research, 2008Co-Authors: Thorsten Reemtsma, Anja These, Andreas Springer, Michael W LinscheidAbstract:Size-exclusion chromatography was coupled to electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (SEC-FTICR-MS) to separate a Fulvic acid isolate into three size fractions and to determine the elemental composition of Fulvic Acids in these fractions. Molecular formulas of about 3000 ions in the mass range of 200-700 Da were derived, many of which occur in all three fractions and follow the same system of elemental composition. Product ion spectra generated by SEC coupled to quadrupol-time-of-flight-MS (Q-TOF-MS) confirmed that the ions of all three fractions are basically polycarboxylates with hardly any other functional moiety. However, SEC-FTICR-MS revealed that the ions generated from the high molecular weight (HMW) fraction are enriched in carboxyl groups and are more aromatic as compared with the low molecular weight (LMW) fraction. These findings support the idea that the HMW Fulvic Acids are formed from LMW Fulvic Acids. The shift in the relative frequency of ions from the LMW to the HMW fraction is in line with different interaction mechanisms: HMW Fulvic Acids may be aggregates held together by electrostatic interaction of the carboxylate groups via hydrogen bonds or with polyvalent cations or by hydrophobic interaction of their carbon backbone, or consist of LMW Fulvic Acids covalently bound to each other or to (aliphatic) alcohols.
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identification of Fulvic Acids and sulfated and nitrated analogues in atmospheric aerosol by electrospray ionization fourier transform ion cyclotron resonance mass spectrometry
Analytical Chemistry, 2006Co-Authors: Thorsten Reemtsma, Anja These, And Andreas Springer, Prasanna Venkatachari, Xiaoyan Xia, Phillip K Hopke, Michael W LinscheidAbstract:The water-soluble organic fractions of aerosol samples collected in Riverside, CA, in summer 2005 were analyzed by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). Elemental compositions of about 1000 molecular species were determined in the range m/z 220-420, and four series of organic compounds were identified, Fulvic Acids, and S-containing, N-containing, and S- and N-containing molecules. Low-resolution product ion spectra proved the presence of organosulfates, organonitrates, and mixed organosulfates and -nitrates that appear to be structurally closely related to each other and to the Fulvic Acids. This is the first unambiguous detection of Fulvic acid molecules and sulfated components in atmospheric aerosol and the first detection even of nitrated analogues. These species provide new clues to the nature of particulate organic matter in atmospheric aerosol.
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Fulvic Acids as transition state of organic matter indications from high resolution mass spectrometry
Environmental Science & Technology, 2006Co-Authors: Thorsten Reemtsma, Anja These, And Andreas Springer, Michael W LinscheidAbstract:Fulvic Acids are one of the largest classes of dissolved organic matter, but they are poorly defined and of unclear origin. Three Fulvic acid isolates of different origin were analyzed by size-exclusion chromatography coupled to electrospray ionization-Fourier-transform ion cyclotron resonance (FTICR)-mass spectrometry, and molecular formulas for 700-1900 species in these isolates were derived. All three isolates show the same pattern in the elemental composition of their molecules and a large congruence in the molecular sets. It is proposed that the elemental and structural regularity of Fulvic acid molecules does not indicate one common precursor material and formation process, but that this regularity is due to both the strong reworking of source materials in the environment and the valency of the three elements (C, H, O) from which most Fulvic acid molecules are formed. Potential molecular formulas of Fulvic Acids were predicted for a mass range of 60 amu based on a few presumptions. A good agreement was found between the predicted and the detected molecular formulas, and it is concluded that (poly-)carboxylic Acids with very limited number of hydroxy groups are the major compound class in Fulvic acid isolates. It appears that Fulvic Acids are metastable molecules that characterize a state of transition of diverse precursor compounds during their oxidation.
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comparative investigation of low molecular weight Fulvic Acids of different origin by sec q tof ms new insights into structure and formation
Environmental Science & Technology, 2005Co-Authors: Thorsten Reemtsma, Anja TheseAbstract:Size exclusion chromatography (SEC) coupled to electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS) was used to analyze the elemental composition and structure of low-molecular-weight Fulvic acid molecules. It is shown that the set of hundreds of individual molecules form a homogeneous and structurally unique class of compounds that can be clearly differentiated from any other class of biogenic matter investigated to date. The molecular composition of low-molecular-weight Fulvic Acids in isolates of very different origin (surface water, groundwater, peat) is virtually indistinguishable. Significant and characteristic differences are, however, recognized when qualitative information and quantitative information provided by ESI-Q-TOF-MS are linked to each other. The relative frequency of the various molecules in each mixture can differ significantly, with the peat showing higher intensity of the aromatic and less carboxylated molecules of this set, whereas the aquatic Fulvic ac...
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determination of molecular formulas and structural regularities of low molecular weight Fulvic Acids by size exclusion chromatography with electrospray ionization quadrupole time of flight mass spectrometry
Rapid Communications in Mass Spectrometry, 2004Co-Authors: Anja These, Marcus Winkler, Christoph Thomas, Thorsten ReemtsmaAbstract:Size-exclusion chromatography was coupled to a quadrupole time-of-flight mass spectrometer using electrospray ionization in the negative ion mode to analyze Suwannee River Fulvic acid. About 220 exact masses of low molecular weight Fulvic Acids (FAs) were measured in the range from m/z 190 to 350, and molecular formulas could be deduced for all these molecular masses. All molecular formulas can be described by the superimposition of three homologous series in the FA mixture: (a) a series of hydrogen homologs constituted of five to six members for a given number of carbons and oxygens; (b) a series of alkyl chain homologs with stepwise addition of one methylene group; and (c) isobaric compounds that differ by the formal replacement of an oxygen atom by a methane group. Product ion spectra of the FA species reflect the repeated parallel losses of carbon dioxide and water. The minimum number of carboxylate groups and the maximum number of hydroxy moieties could be determined from the product ion spectra. Furthermore, it was obvious that the structural differences between homologs in the three series are located in the carbon backbone of the FA rather than in its extremities that are expelled as neutral fragments. These structural regularities reduce the complexity of FA mixtures to a certain set of yet unknown basic structures.
Anja These - One of the best experts on this subject based on the ideXlab platform.
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differences in the molecular composition of Fulvic acid size fractions detected by size exclusion chromatography on line fourier transform ion cyclotron resonance fticr mass spectrometry
Water Research, 2008Co-Authors: Thorsten Reemtsma, Anja These, Andreas Springer, Michael W LinscheidAbstract:Size-exclusion chromatography was coupled to electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (SEC-FTICR-MS) to separate a Fulvic acid isolate into three size fractions and to determine the elemental composition of Fulvic Acids in these fractions. Molecular formulas of about 3000 ions in the mass range of 200-700 Da were derived, many of which occur in all three fractions and follow the same system of elemental composition. Product ion spectra generated by SEC coupled to quadrupol-time-of-flight-MS (Q-TOF-MS) confirmed that the ions of all three fractions are basically polycarboxylates with hardly any other functional moiety. However, SEC-FTICR-MS revealed that the ions generated from the high molecular weight (HMW) fraction are enriched in carboxyl groups and are more aromatic as compared with the low molecular weight (LMW) fraction. These findings support the idea that the HMW Fulvic Acids are formed from LMW Fulvic Acids. The shift in the relative frequency of ions from the LMW to the HMW fraction is in line with different interaction mechanisms: HMW Fulvic Acids may be aggregates held together by electrostatic interaction of the carboxylate groups via hydrogen bonds or with polyvalent cations or by hydrophobic interaction of their carbon backbone, or consist of LMW Fulvic Acids covalently bound to each other or to (aliphatic) alcohols.
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identification of Fulvic Acids and sulfated and nitrated analogues in atmospheric aerosol by electrospray ionization fourier transform ion cyclotron resonance mass spectrometry
Analytical Chemistry, 2006Co-Authors: Thorsten Reemtsma, Anja These, And Andreas Springer, Prasanna Venkatachari, Xiaoyan Xia, Phillip K Hopke, Michael W LinscheidAbstract:The water-soluble organic fractions of aerosol samples collected in Riverside, CA, in summer 2005 were analyzed by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). Elemental compositions of about 1000 molecular species were determined in the range m/z 220-420, and four series of organic compounds were identified, Fulvic Acids, and S-containing, N-containing, and S- and N-containing molecules. Low-resolution product ion spectra proved the presence of organosulfates, organonitrates, and mixed organosulfates and -nitrates that appear to be structurally closely related to each other and to the Fulvic Acids. This is the first unambiguous detection of Fulvic acid molecules and sulfated components in atmospheric aerosol and the first detection even of nitrated analogues. These species provide new clues to the nature of particulate organic matter in atmospheric aerosol.
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Fulvic Acids as transition state of organic matter indications from high resolution mass spectrometry
Environmental Science & Technology, 2006Co-Authors: Thorsten Reemtsma, Anja These, And Andreas Springer, Michael W LinscheidAbstract:Fulvic Acids are one of the largest classes of dissolved organic matter, but they are poorly defined and of unclear origin. Three Fulvic acid isolates of different origin were analyzed by size-exclusion chromatography coupled to electrospray ionization-Fourier-transform ion cyclotron resonance (FTICR)-mass spectrometry, and molecular formulas for 700-1900 species in these isolates were derived. All three isolates show the same pattern in the elemental composition of their molecules and a large congruence in the molecular sets. It is proposed that the elemental and structural regularity of Fulvic acid molecules does not indicate one common precursor material and formation process, but that this regularity is due to both the strong reworking of source materials in the environment and the valency of the three elements (C, H, O) from which most Fulvic acid molecules are formed. Potential molecular formulas of Fulvic Acids were predicted for a mass range of 60 amu based on a few presumptions. A good agreement was found between the predicted and the detected molecular formulas, and it is concluded that (poly-)carboxylic Acids with very limited number of hydroxy groups are the major compound class in Fulvic acid isolates. It appears that Fulvic Acids are metastable molecules that characterize a state of transition of diverse precursor compounds during their oxidation.
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comparative investigation of low molecular weight Fulvic Acids of different origin by sec q tof ms new insights into structure and formation
Environmental Science & Technology, 2005Co-Authors: Thorsten Reemtsma, Anja TheseAbstract:Size exclusion chromatography (SEC) coupled to electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS) was used to analyze the elemental composition and structure of low-molecular-weight Fulvic acid molecules. It is shown that the set of hundreds of individual molecules form a homogeneous and structurally unique class of compounds that can be clearly differentiated from any other class of biogenic matter investigated to date. The molecular composition of low-molecular-weight Fulvic Acids in isolates of very different origin (surface water, groundwater, peat) is virtually indistinguishable. Significant and characteristic differences are, however, recognized when qualitative information and quantitative information provided by ESI-Q-TOF-MS are linked to each other. The relative frequency of the various molecules in each mixture can differ significantly, with the peat showing higher intensity of the aromatic and less carboxylated molecules of this set, whereas the aquatic Fulvic ac...
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determination of molecular formulas and structural regularities of low molecular weight Fulvic Acids by size exclusion chromatography with electrospray ionization quadrupole time of flight mass spectrometry
Rapid Communications in Mass Spectrometry, 2004Co-Authors: Anja These, Marcus Winkler, Christoph Thomas, Thorsten ReemtsmaAbstract:Size-exclusion chromatography was coupled to a quadrupole time-of-flight mass spectrometer using electrospray ionization in the negative ion mode to analyze Suwannee River Fulvic acid. About 220 exact masses of low molecular weight Fulvic Acids (FAs) were measured in the range from m/z 190 to 350, and molecular formulas could be deduced for all these molecular masses. All molecular formulas can be described by the superimposition of three homologous series in the FA mixture: (a) a series of hydrogen homologs constituted of five to six members for a given number of carbons and oxygens; (b) a series of alkyl chain homologs with stepwise addition of one methylene group; and (c) isobaric compounds that differ by the formal replacement of an oxygen atom by a methane group. Product ion spectra of the FA species reflect the repeated parallel losses of carbon dioxide and water. The minimum number of carboxylate groups and the maximum number of hydroxy moieties could be determined from the product ion spectra. Furthermore, it was obvious that the structural differences between homologs in the three series are located in the carbon backbone of the FA rather than in its extremities that are expelled as neutral fragments. These structural regularities reduce the complexity of FA mixtures to a certain set of yet unknown basic structures.
Michael W Linscheid - One of the best experts on this subject based on the ideXlab platform.
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differences in the molecular composition of Fulvic acid size fractions detected by size exclusion chromatography on line fourier transform ion cyclotron resonance fticr mass spectrometry
Water Research, 2008Co-Authors: Thorsten Reemtsma, Anja These, Andreas Springer, Michael W LinscheidAbstract:Size-exclusion chromatography was coupled to electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (SEC-FTICR-MS) to separate a Fulvic acid isolate into three size fractions and to determine the elemental composition of Fulvic Acids in these fractions. Molecular formulas of about 3000 ions in the mass range of 200-700 Da were derived, many of which occur in all three fractions and follow the same system of elemental composition. Product ion spectra generated by SEC coupled to quadrupol-time-of-flight-MS (Q-TOF-MS) confirmed that the ions of all three fractions are basically polycarboxylates with hardly any other functional moiety. However, SEC-FTICR-MS revealed that the ions generated from the high molecular weight (HMW) fraction are enriched in carboxyl groups and are more aromatic as compared with the low molecular weight (LMW) fraction. These findings support the idea that the HMW Fulvic Acids are formed from LMW Fulvic Acids. The shift in the relative frequency of ions from the LMW to the HMW fraction is in line with different interaction mechanisms: HMW Fulvic Acids may be aggregates held together by electrostatic interaction of the carboxylate groups via hydrogen bonds or with polyvalent cations or by hydrophobic interaction of their carbon backbone, or consist of LMW Fulvic Acids covalently bound to each other or to (aliphatic) alcohols.
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identification of Fulvic Acids and sulfated and nitrated analogues in atmospheric aerosol by electrospray ionization fourier transform ion cyclotron resonance mass spectrometry
Analytical Chemistry, 2006Co-Authors: Thorsten Reemtsma, Anja These, And Andreas Springer, Prasanna Venkatachari, Xiaoyan Xia, Phillip K Hopke, Michael W LinscheidAbstract:The water-soluble organic fractions of aerosol samples collected in Riverside, CA, in summer 2005 were analyzed by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). Elemental compositions of about 1000 molecular species were determined in the range m/z 220-420, and four series of organic compounds were identified, Fulvic Acids, and S-containing, N-containing, and S- and N-containing molecules. Low-resolution product ion spectra proved the presence of organosulfates, organonitrates, and mixed organosulfates and -nitrates that appear to be structurally closely related to each other and to the Fulvic Acids. This is the first unambiguous detection of Fulvic acid molecules and sulfated components in atmospheric aerosol and the first detection even of nitrated analogues. These species provide new clues to the nature of particulate organic matter in atmospheric aerosol.
-
Fulvic Acids as transition state of organic matter indications from high resolution mass spectrometry
Environmental Science & Technology, 2006Co-Authors: Thorsten Reemtsma, Anja These, And Andreas Springer, Michael W LinscheidAbstract:Fulvic Acids are one of the largest classes of dissolved organic matter, but they are poorly defined and of unclear origin. Three Fulvic acid isolates of different origin were analyzed by size-exclusion chromatography coupled to electrospray ionization-Fourier-transform ion cyclotron resonance (FTICR)-mass spectrometry, and molecular formulas for 700-1900 species in these isolates were derived. All three isolates show the same pattern in the elemental composition of their molecules and a large congruence in the molecular sets. It is proposed that the elemental and structural regularity of Fulvic acid molecules does not indicate one common precursor material and formation process, but that this regularity is due to both the strong reworking of source materials in the environment and the valency of the three elements (C, H, O) from which most Fulvic acid molecules are formed. Potential molecular formulas of Fulvic Acids were predicted for a mass range of 60 amu based on a few presumptions. A good agreement was found between the predicted and the detected molecular formulas, and it is concluded that (poly-)carboxylic Acids with very limited number of hydroxy groups are the major compound class in Fulvic acid isolates. It appears that Fulvic Acids are metastable molecules that characterize a state of transition of diverse precursor compounds during their oxidation.
William T Cooper - One of the best experts on this subject based on the ideXlab platform.
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exact masses and chemical formulas of individual suwannee river Fulvic Acids from ultrahigh resolution electrospray ionization fourier transform ion cyclotron resonance mass spectra
Analytical Chemistry, 2003Co-Authors: Alexandra C Stenson, Alan G Marshall, William T CooperAbstract:Molecular formulas have been assigned for 4626 individual Suwannee River Fulvic Acids based on accurate mass measurements from ions generated by electrospray ionization and observed by ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS). Formula assignments were possible because of the mass accuracy of FTICR MS at high field (9.4 T) and the regular mass spacing patterns found in Fulvic acid mixtures. Sorting the 4626 individually observed ions according to Kendrick mass defect and nominal mass series (z* score) revealed that all could be assigned to 1 of 266 distinct homologous series that differ in oxygen content and double bond equivalence. Tandem mass spectrometry based on infrared multiphoton dissociation identified labile fragments of Fulvic acid molecules, whose chemical formulas led to plausible structures consistent with degraded lignin as a source of Suwannee River Fulvic Acids.
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high resolution fourier transform ion cyclotron resonance mass spectrometry of humic and Fulvic Acids by laser desorption ionization and electrospray ionization
Energy & Fuels, 1997Co-Authors: Anne Fievre, Touradj Solouki, Alan G Marshall, William T CooperAbstract:High-field (9.4 T) Fourier transform ion cyclotron resonance (FT-ICR) mass spectra of standard Suwannee River humic and Fulvic Acids have been obtained by use of laser desorption (LDI) and electrospray (ESI) ionization. The LDI FT-ICR mass spectrum was similar to those observed previously, with ions at essentially every nominal value, 200 ≤ m/z ≤ 800. In contrast, the ESI FT-ICR mass spectrum, although still containing ions at most values in the 200 ≤ m/z ≤ 800 range, was dominated by a relatively few prominent species. ESI FT-ICR mass spectra of standard humic and Fulvic acid isolates were similar. Although many ionic species appeared in both Fulvic acid and humic acid ESI FT-ICR mass spectra, the Fulvic acid mass spectrum contained more highly charged species. Subfractions of the Fulvic acid mixture isolated by an HPLC procedure yielded similar mass spectra. The stability of high-mass ions produced by ESI combined with the high-mass resolution capability of FT-ICR MS allow for precise determination of m...
Michael A Freitas - One of the best experts on this subject based on the ideXlab platform.
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high resolution fourier transform ion cyclotron resonance mass spectrometry of humic and Fulvic Acids improvements and comparisons
Analytical Chemistry, 2002Co-Authors: Elizabeth B Kujawinski, Patrick G Hatcher, Michael A FreitasAbstract:Full structural characterization of complex mixtures such as humic acid extracts has been elusive because of insufficient compound resolution with conventional techniques. Using electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry, we were able to resolve individual compounds within humic and Fulvic acid mixtures (mass resolving power ∼80 000 at 300 m/z). We examined two samples in detail: (1) dissolved organic matter (primarily Fulvic Acids) from Suwannee River, GA, and (2) a humic acid extract from a degraded wood collected on Mt. Rainier, WA. Sample conditions (such as solvent, pH, and concentration) and instrument parameters (such as source voltages, trapping potentials, and excitation parameters) were optimized to yield the highest mass resolving power with the least mass discrimination in positive ion mode. High resolving power was achieved with low ion densities combined with coadding numerous scans. The increased resolution allowed molecular-level compa...
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high resolution fourier transform ion cyclotron resonance mass spectrometry of humic and Fulvic Acids improvements and comparisons
Analytical Chemistry, 2002Co-Authors: Elizabeth B Kujawinski, Patrick G Hatcher, Michael A FreitasAbstract:Full structural characterization of complex mixtures such as humic acid extracts has been elusive because of insufficient compound resolution with conventional techniques. Using electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry, we were able to resolve individual compounds within humic and Fulvic acid mixtures (mass resolving power approximately 80000 at 300 m/z). We examined two samples in detail: (1) dissolved organic matter (primarily Fulvic Acids) from Suwannee River, GA, and (2) a humic acid extract from a degraded wood collected on Mt. Rainier, WA. Sample conditions (such as solvent, pH, and concentration) and instrument parameters (such as source voltages, trapping potentials, and excitation parameters) were optimized to yield the highest mass resolving power with the least mass discrimination in positive ion mode. High resolving power was achieved with low ion densities combined with coadding numerous scans. The increased resolution allowed molecular-level comparisons of the two samples which in turn could be used to estimate the relative similarity of individual compound distribution as well as an indication of the dominant diagenetic processes in the two source environments.
