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Jürgen H. Gross - One of the best experts on this subject based on the ideXlab platform.
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Basic poly(propylene glycols) as reference compounds for internal mass calibratIon in Positive-Ion matrix-assisted laser desorptIon/IonizatIon mass spectrometry.
European journal of mass spectrometry (Chichester England), 2017Co-Authors: Jürgen H. GrossAbstract:Basic poly(propylene glycols), commercially available under the trade name Jeffamine, are evaluated for their potential use as internal mass calibrants in matrix-assisted laser desorptIon/IonizatIon-time-of-flight-mass spectrometry. Due to their basic amino endgroups Jeffamines are expected to deliver [M+H]+ Ions in higher yields than neutral poly(propylene glycols) or poly(ethylene glycols). Aiming at accurate mass measurements and molecular formula determinatIons by matrix-assisted laser desorptIon/IonizatIon-time-of-flight-mass spectrometry, four Jeffamines (M-600, M-2005, D-400, D-230) were thus compared. As a result, Jeffamine M-2005 is introduced as a new mass calibrant for Positive-Ion matrix-assisted laser desorptIon/IonizatIon-time-of-flight-mass spectrometry in the range of m/z 200-1200 and the reference mass list is provided. While Jeffamine M-2005 is compatible with α-cyano-4-hydroxycinnamic acid, 2,5-dihydroxybenzoic acid, and 2-[(2 E)-3-(4- tert-butylphenyl)-2-methylprop-2-enylidene]malonitrile matrix, its use in combinatIon with 2-[(2 E)-3-(4- tert-butylphenyl)-2-methylprop-2-enylidene]malonitrile provides best results due to low laser fluence requirements. ApplicatIons to PEG 300, PEG 600, the Ionic liquid trihexyl(tetradecyl)-phosphonium tris(pentafluoroethyl)-trifluorophosphate, and [60]fullerene demonstrate mass accuracies of 2-5 ppm.
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High-mass cluster Ions of Ionic liquids in Positive-Ion and negative-Ion DART-MS and their applicatIon for wide-range mass calibratIons
Analytical and Bioanalytical Chemistry, 2014Co-Authors: Jürgen H. GrossAbstract:Eight Ionic liquids (ILs) are subjected to both Positive-Ion and negative-Ion direct analyses in real time (DART) Fourier transform Ion cyclotron resonance (FT-ICR) mass spectrometry (MS). First, their ability to deliver evenly distributed cluster Ion series covering a wide m / z range is explored. Then, one of the ILs exhibiting particularly useful cluster Ion series in either Ion polarity is applied for mass calibratIon. Using 1-butyl-3-methylimidazolium tricyanomethide delivers Positive cluster Ions suitable for mass calibratIon in the m / z 100–4,000 range and covers the m / z 100–2,000 range in negative-Ion DART-MS. The corresponding mass reference lists are provided for either polarity. Furthermore, based on 1-butyl-3-methylimidazolium tricyanomethide, a high-mass record of m / z > 5,000 for Positive-Ion DART-MS is presented. The mass calibratIon procedure is finally validated by applicatIon to established standard compounds such as polydimethylsiloxanes, perfluorononanoic acid, and Ultramark 1621, a mixture of hexakis (fluoroalkoxy) phosphazenes. Further proof is presented by consistent exact mass differences between adjacent cluster Ions. Figure Direct analysis in real time mass spectrometry (DART-MS) can deliver Ionic liquid cluster Ions reaching well beyond m/z 5,000. These Positive and negative cluster Ions may well serve for wide-range mass calibratIon in DART-MS
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high mass cluster Ions of Ionic liquids in Positive Ion and negative Ion dart ms and their applicatIon for wide range mass calibratIons
Analytical and Bioanalytical Chemistry, 2014Co-Authors: Jürgen H. GrossAbstract:Eight Ionic liquids (ILs) are subjected to both Positive-Ion and negative-Ion direct analyses in real time (DART) Fourier transform Ion cyclotron resonance (FT-ICR) mass spectrometry (MS). First, their ability to deliver evenly distributed cluster Ion series covering a wide m/z range is explored. Then, one of the ILs exhibiting particularly useful cluster Ion series in either Ion polarity is applied for mass calibratIon. Using 1-butyl-3-methylimidazolium tricyanomethide delivers Positive cluster Ions suitable for mass calibratIon in the m/z 100–4,000 range and covers the m/z 100–2,000 range in negative-Ion DART-MS. The corresponding mass reference lists are provided for either polarity. Furthermore, based on 1-butyl-3-methylimidazolium tricyanomethide, a high-mass record of m/z > 5,000 for Positive-Ion DART-MS is presented. The mass calibratIon procedure is finally validated by applicatIon to established standard compounds such as polydimethylsiloxanes, perfluorononanoic acid, and Ultramark 1621, a mixture of hexakis (fluoroalkoxy) phosphazenes. Further proof is presented by consistent exact mass differences between adjacent cluster Ions.
Keng H Chung - One of the best experts on this subject based on the ideXlab platform.
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characterizatIon of sulfide compounds in petroleum selective oxidatIon followed by Positive Ion electrospray fourier transform Ion cyclotron resonance mass spectrometry
Analytical Chemistry, 2010Co-Authors: Chunming Xu, Yahe Zhang, Suoqi Zhao, Keng H ChungAbstract:A novel analytical method for identifying sulfides in petroleum and its fractIons was developed. Sulfides in petroleum were selectively oxidized into sulfoxides using tetrabutylammonium periodate (TBAPI) and identified by Positive-Ion electrospray IonizatIon (ESI) Fourier transform-Ion cyclotron resonance mass spectrometry (FT-ICR MS). A variety of model sulfur compounds were examined to evaluate the selective oxidizatIon and IonizatIon efficiencies for sulfur compounds in petroleum. Two fractIons, straight-run diesel and saturates of Athabasca oilsands bitumen were investigated using this approach. The oxidizatIon process was highly selective for sulfides from thiophenes and aromatic hydrocarbons. OxidatIon generated sulfoxides were Ionized by Positive-Ion ESI and analyzed by FT-ICR MS. Mass spectra revealed the compositIon characteristics of sulfides in the diesel by contrasting the double bond equivalence (DBE) and carbon number distributIon of sulfur compounds before and after oxidatIon. The abundant ...
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characterizatIon of basic nitrogen species in coker gas oils by Positive Ion electrospray IonizatIon fourier transform Ion cyclotron resonance mass spectrometry
Energy & Fuels, 2010Co-Authors: Chunming Xu, Suoqi Zhao, Keng H Chung, Yahe ZhangAbstract:Six coker gas oils (CGOs) and three basic fractIons extracted from one of the CGOs by 0.1, 0.4, and 1 M HCl hydrochloric acid were characterized by Positive-Ion electrospray IonizatIon Fourier transform Ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and compared to those analyzed by gas chromatography mass spectrometry (GC-MS). The ultra high mass resolving power and high mass accuracy of FT-ICR MS allow the assignment of a unique elemental compositIon to each peak in the mass spectrum. Basic nitrogen species were characterized by class, type, and carbon number. The mass spectra of the CGOs at the 200−500 Da mass range were similar, but the distributIon of double bond equivalence (DBE) versus carbon number were different. Among the N, N2, NO, and NS that were identified in CGOs, the N class nitrogen species were dominant. The results showed that hydrotreating reduced the relative abundance of all class species, except for the N class species. This suggests that some N class species are refracto...
Yahe Zhang - One of the best experts on this subject based on the ideXlab platform.
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characterizatIon of sulfide compounds in petroleum selective oxidatIon followed by Positive Ion electrospray fourier transform Ion cyclotron resonance mass spectrometry
Analytical Chemistry, 2010Co-Authors: Chunming Xu, Yahe Zhang, Suoqi Zhao, Keng H ChungAbstract:A novel analytical method for identifying sulfides in petroleum and its fractIons was developed. Sulfides in petroleum were selectively oxidized into sulfoxides using tetrabutylammonium periodate (TBAPI) and identified by Positive-Ion electrospray IonizatIon (ESI) Fourier transform-Ion cyclotron resonance mass spectrometry (FT-ICR MS). A variety of model sulfur compounds were examined to evaluate the selective oxidizatIon and IonizatIon efficiencies for sulfur compounds in petroleum. Two fractIons, straight-run diesel and saturates of Athabasca oilsands bitumen were investigated using this approach. The oxidizatIon process was highly selective for sulfides from thiophenes and aromatic hydrocarbons. OxidatIon generated sulfoxides were Ionized by Positive-Ion ESI and analyzed by FT-ICR MS. Mass spectra revealed the compositIon characteristics of sulfides in the diesel by contrasting the double bond equivalence (DBE) and carbon number distributIon of sulfur compounds before and after oxidatIon. The abundant ...
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characterizatIon of basic nitrogen species in coker gas oils by Positive Ion electrospray IonizatIon fourier transform Ion cyclotron resonance mass spectrometry
Energy & Fuels, 2010Co-Authors: Chunming Xu, Suoqi Zhao, Keng H Chung, Yahe ZhangAbstract:Six coker gas oils (CGOs) and three basic fractIons extracted from one of the CGOs by 0.1, 0.4, and 1 M HCl hydrochloric acid were characterized by Positive-Ion electrospray IonizatIon Fourier transform Ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and compared to those analyzed by gas chromatography mass spectrometry (GC-MS). The ultra high mass resolving power and high mass accuracy of FT-ICR MS allow the assignment of a unique elemental compositIon to each peak in the mass spectrum. Basic nitrogen species were characterized by class, type, and carbon number. The mass spectra of the CGOs at the 200−500 Da mass range were similar, but the distributIon of double bond equivalence (DBE) versus carbon number were different. Among the N, N2, NO, and NS that were identified in CGOs, the N class nitrogen species were dominant. The results showed that hydrotreating reduced the relative abundance of all class species, except for the N class species. This suggests that some N class species are refracto...
Chunming Xu - One of the best experts on this subject based on the ideXlab platform.
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characterizatIon of sulfide compounds in petroleum selective oxidatIon followed by Positive Ion electrospray fourier transform Ion cyclotron resonance mass spectrometry
Analytical Chemistry, 2010Co-Authors: Chunming Xu, Yahe Zhang, Suoqi Zhao, Keng H ChungAbstract:A novel analytical method for identifying sulfides in petroleum and its fractIons was developed. Sulfides in petroleum were selectively oxidized into sulfoxides using tetrabutylammonium periodate (TBAPI) and identified by Positive-Ion electrospray IonizatIon (ESI) Fourier transform-Ion cyclotron resonance mass spectrometry (FT-ICR MS). A variety of model sulfur compounds were examined to evaluate the selective oxidizatIon and IonizatIon efficiencies for sulfur compounds in petroleum. Two fractIons, straight-run diesel and saturates of Athabasca oilsands bitumen were investigated using this approach. The oxidizatIon process was highly selective for sulfides from thiophenes and aromatic hydrocarbons. OxidatIon generated sulfoxides were Ionized by Positive-Ion ESI and analyzed by FT-ICR MS. Mass spectra revealed the compositIon characteristics of sulfides in the diesel by contrasting the double bond equivalence (DBE) and carbon number distributIon of sulfur compounds before and after oxidatIon. The abundant ...
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characterizatIon of basic nitrogen species in coker gas oils by Positive Ion electrospray IonizatIon fourier transform Ion cyclotron resonance mass spectrometry
Energy & Fuels, 2010Co-Authors: Chunming Xu, Suoqi Zhao, Keng H Chung, Yahe ZhangAbstract:Six coker gas oils (CGOs) and three basic fractIons extracted from one of the CGOs by 0.1, 0.4, and 1 M HCl hydrochloric acid were characterized by Positive-Ion electrospray IonizatIon Fourier transform Ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and compared to those analyzed by gas chromatography mass spectrometry (GC-MS). The ultra high mass resolving power and high mass accuracy of FT-ICR MS allow the assignment of a unique elemental compositIon to each peak in the mass spectrum. Basic nitrogen species were characterized by class, type, and carbon number. The mass spectra of the CGOs at the 200−500 Da mass range were similar, but the distributIon of double bond equivalence (DBE) versus carbon number were different. Among the N, N2, NO, and NS that were identified in CGOs, the N class nitrogen species were dominant. The results showed that hydrotreating reduced the relative abundance of all class species, except for the N class species. This suggests that some N class species are refracto...
Su Chen - One of the best experts on this subject based on the ideXlab platform.
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Analysis of glycoalkaloids from potato shoots and tomatoes by four-sector tandem mass spectrometry with scanning-array detectIon: comparison of Positive Ion and negative Ion methods.
Analytical Biochemistry, 1994Co-Authors: Su Chen, Fred A. Mellon, Peter J. Derrick, Keith R PriceAbstract:A wide range of glycoalkaloids from potato shoots and tomatoes, including trisaccharide-containing glycoalkaloids (alpha-chaconine, alpha-solanine, and alpha-solasonine), tetrasaccharide-containing glycoalkaloids (alpha-tomatine and demissine), and disaccharide-containing glycoalkaloids (beta 1-chaconine, beta 2-chaconine, and beta-solamargine), have been studied by both Positive and negative Ion liquid secondary Ion and four-sector tandem mass spectrometry with scanning-array detectIon. In Positive Ion mode, collisIonally induced dissociatIon tandem mass spectra of the [M + H]+ Ions induce three major fragmentatIon processes, Z cleavage, Y cleavage, and 1,5X cleavage, which are structurally informative. Signals resulting from Z0, Y0, and 1,5X0 cleavages provide informatIon on the nature of various aglycone moieties in all glycoalkaloids. Linkages and positIons of the sugars in trisaccharide- and tetrasaccharide-containing glycoalkaloids are indicated by the presence or absence of the Ions corresponding to Z alpha/beta and Y alpha/beta cleavages and intensity differences of the peaks due to 1,5X alpha and 1,5X beta cleavages, respectively. In negative Ion mode, collisIonally induced dissociatIon tandem mass spectra of the [M - H]- Ions induce Y cleavage as the major fragmentatIon process. The locatIon of the terminal sugars in branched trisaccharide and tetrasaccharide glycoalkaloids is indicated by the difference in intensity of the Ions due to Y alpha cleavage and Y beta cleavage. Isomeric structures cannot, however, be differentiated unambiguously; complete structural assignment is only possible by NMR of purified components. Both Positive and negative Ion tandem mass spectrometry are considered to be suitable for the characterisatIon of glycoalkaloids in mixtures. The Positive Ion method has the advantage of (i) a lower detectIon limit than in conventIonal mass spectrometry; (ii) numerous and intense fragment Ions which are structurally informative; and (iii) the capability of analyzing minor components in crude extracts. Comparable analysis by other analytical means would not have provided the amount of structural informatIon on the components in the glycoalkaloid mixtures.
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Structural analysis of underivatized and derivatized aminophospholipids and phosphatidic acid by Positive Ion liquid secondary Ion and collisIonally induced dissociatIon tandem mass spectrometry
Journal of biochemistry, 1994Co-Authors: Su ChenAbstract:This paper describes an approach for structurally analyzing aminophospholipids, including glycerophosphatidylethanolamine, glycerophosphatidylserine and their lyso analogues, and glycerophosphatidic acid by Positive-Ion liquid secondary-Ion and four-sector tandem mass spectrometry. Polar head groups and the compositIon and positIon of the fatty acid chains in aminophospholipid species as well as diacyl and monoacyl phosphatidylethanolamine and their plasmalogen species can be characterized by collisIonally induced dissociatIon of [M+H]+ Ions of underivatized molecular species. Tandem mass spectrometry of [M+Na]+ and [M + 2Na-H]+ Ions of 9-fluorenylmethyloxycarbonyl-derivatized glycerophosphatidylethanolamine and glycerophosphatidylserine induces fragmentatIon processes, but product Ions are generally less structurally informative. CollisIonally induced dissociatIon of [M + 2Na-H]+ Ions of the molecular species of glycerophosphatidic acid not only yields informatIon on the compositIon and positIon of fatty acid chains, but also allows the double bond locatIon to be identified. This common Positive-Ion method is particularly effective in characterizing the molecular species of natural ethanolamine glycerophospholipids because of the advantage of a low detectIon limit. This approach also represents a useful alternative for the analysis of the molecular species from natural aminophospholipids by tandem mass spectrometry.
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IdentificatIon of Aminophospholipid Stereomers by Positive-Ion Fast Atom Bombardment Combined with CollisIonal ActivatIon Mass-analysed Ion Kinetic Energy Analysis and High-Performance Liquid Chromatography
Organic Mass Spectrometry, 1992Co-Authors: Su Chen, Giampaolo Menon, Pietro TraldiAbstract:Two methods for the identificatIon of aminophospholipid stereomers are described. After a chemical derivatizatIon, 9-fluorenylmethoxycarbonyl derivatives of diacyl-sn-2- and diacyl-sn-3-phosphoserine and diacyl-sn-2- and diacyl-sn-3-phosphoethanolamine can be characterized by Positive-Ion fast atom bombardment combined with collisIonal activatIon mass-analysed Ion kinetic energy analysis based on the differentiatIon of relative abundances [M + H + diethanolamine − 89]+ and [M + H]+ fragments derived from [M + H + diethanolamine]+ Ions, the protonated solvated molecules, and normal phase high-performance liquid chromatography on the basis of different elutIon times of the derivatives of the aminophospholipid stereomers on an aminopropyl-bonded column.
