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Dean Guo - One of the best experts on this subject based on the ideXlab platform.
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low energy induced homolytic Fragmentation of flavonol 3 o glycosides by negative electrospray ionization tandem mass spectrometry
Rapid Communications in Mass Spectrometry, 2014Co-Authors: Wenzhi Yang, Xue Qiao, Qing Wang, Dean GuoAbstract:RATIONALE Negative ESI-QIT-MS of several subtypes of flavonoid O-glycosides is known to produce deprotonated molecular ions which undergo homolytic Fragmentation at the glycosidic bond upon collision-induced dissociation (CID). However, these subtypes have never been simultaneously compared under unified MS conditions. METHODS The (−)-ESI-MSn Fragmentations of 69 flavonoid O-glycosides, involving eight subtypes, were analyzed using a quadrupole ion-trap mass spectrometer with collision energies varying from 18–44%. Factors influencing the homolytic glycosidic bond Fragmentation, such as collision energy, hydroxylation of aglycone, and glycosylation pattern, were comprehensively studied. RESULTS Under the unified CID-QIT-MS2 conditions, the precursor deprotonated molecular ions [M–H]– for 3-O-glycosyl, 3,7-di-O-glycosyl and 3,6,7-tri-O-glycosyl flavonols experienced homolytic Fragmentation at the glycosidic bond and generated the radical aglycone ion [Y0–H]–•. This gas-phase CID Fragmentation behavior was not observed for the other subtypes. A general trend was found that hydroxyl substitution at C-6, glycosylation at C-6/C-7, and acetylation of the saccharide moiety remarkably suppressed this Fragmentation. In addition, flavonol 3-O-diglycosides (disaccharides) possessing a 1 → 2 glycosidic bond generated more abundant [Y0–H]–• product ions than those with a 1 → 3 or 1 → 6 bond. The terminal sugar triggered the homolytic Fragmentation in the order Rha > Xyl > Glc. Moreover, new counterexamples were found for previously reported Fragmentation rules. CONCLUSIONS The low-energy CID homolytic Fragmentation was diagnostic for structural identification of flavonol 3-O-glycosides. We have summarized key factors affecting this Fragmentation. The results could be useful for rapid characterization of flavonoid O-glycosides in complicated herbal extracts. Copyright © 2014 John Wiley & Sons, Ltd.
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characterization of phenolic compounds in the fruits of forsythia suspensa by high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry
Rapid Communications in Mass Spectrometry, 2007Co-Authors: Hui Guo, Aihua Liu, Min Yang, Dean GuoAbstract:Phenolic compounds are the major bioactive constituents of Forsythia suspensa, an important Chinese herbal medicine used for the treatment of various infectious diseases. Fragmentation behaviors of the phenolic compounds in F. suspensa were investigated by using a high-performance liquid chromatography/tandem mass spectrometry (HPLC/MSn) method. For common phenylethanoid glycosides, the loss of the caffeoyl moiety was the first Fragmentation step, then sequential losses of rhamnose, hexose and water were observed in further Fragmentations. If a substituent group presented in the β position, the Fragmentation was triggered by initial loss of a substituent group to form structures such as suspensaside A. Then it underwent the common Fragmentation pathways as mentioned above, or eliminated characteristic residues of masses 134 or 152 Da, respectively. The latter pathway is reported here for the first time. The Fragmentation behaviors of furofuran lignans displayed a typical cleavage of the tetrahydrofuran ring. However, the presence of a hydroxyl group at C-1 led to the successive loss of 30 Da. Neutral loss of CO2 and benzyl cleavage were characteristic for lignans with a 2,3-dibenzylbutyrolactone skeleton. A neutral loss of 30 Da was also observed in the Fragmentation pattern of flavonols. These Fragmentation rules were implemented to analyze phenolic compounds in the fruits of F. suspensa. A total of 51 compounds, including 24 phenylethanoid glycosides, 21 lignans and 6 flavonols, were identified or tentatively characterized based on their retention times, UV spectra and MS Fragmentation patterns. Copyright © 2007 John Wiley & Sons, Ltd.
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Characterization of phenolic compounds in the fruits of Forsythia suspensa by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry
质谱学快讯, 2007Co-Authors: Guo Hui, Liu Ai-hua, Ye Min, Yang Min, Dean GuoAbstract:Phenolic compounds are the major bioactive constituents of Forsythia suspensa, an important Chinese herbal medicine used for the treatment of various infectious diseases. Fragmentation behaviors of the phenolic compounds in F. suspensa were investigated by using a high-performance liquid chromatography/tandem mass spectrometry (HPLC/MSn) method. For common phenylethanoid glycosides, the loss of the caffeoyl moiety was the first Fragmentation step, then sequential losses of rhamnose, hexose and water were observed in further Fragmentations. If a substituent group presented in the P position, the Fragmentation was triggered by initial loss of a substituent group to form structures such as suspensaside A. Then it underwent the common Fragmentation pathways as mentioned above, or eliminated characteristic residues of masses 134 or 152 Da, respectively. The latter pathway is reported here for the first time. The Fragmentation behaviors of furofuran lignans displayed a typical cleavage of the tetrahydrofuran ring. However, the presence of a hydroxyl group at C-1 led to the successive loss of 30 Da. Neutral loss Of CO2 and benzyl cleavage were characteristic for lignans with a 2,3-dibenzylbutyrolactone skeleton. A neutral loss of 30 Da was also observed in the Fragmentation pattern of flavonols. These Fragmentation rules were implemented to analyze phenolic compounds in the fruits of F. suspensa. A total of 51 compounds, including 24 phenylethanoid glycosides, 21 lignans and 6 flavonols, were identified or tentatively characterized based on their retention times, UV spectra and MS Fragmentation patterns. Copyright (c) 2007 John Wiley & Sons, Ltd.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000244618400013&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Chemistry, AnalyticalSpectroscopySCI(E)PubMed64ARTICLE5715-7292
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liquid chromatography electrospray ionization mass spectrometry for the characterization of twenty three flavonoids in the extract of dalbergia odorifera
Rapid Communications in Mass Spectrometry, 2005Co-Authors: Rongxia Liu, Hongzhu Guo, Dean GuoAbstract:A method incorporating high-performance liquid chromatography (HPLC) with electrospray ionization and tandem mass spectrometry, with parallel analysis by HPLC with UV detection using a diode-array detector, was developed for the qualitative characterization of flavonoids in D. odorifera. Twenty-three flavonoids, including six isoflavones, six neoflavones, four isoflavanones, three flavanones, two chalcones, one isoflavanonol and one pterocarpan, were unambiguously identified by comparing their retention times, UV and MS spectra with those of authentic compounds. Furthermore, the collision-induced dissociations of the [M-H]- ions were studied to clarify the MS behavior of the different types of flavonoids. In negative ion ESI-MS all the flavonoids yielded prominent [M-H]- ions in the first order mass spectra. Fragments involving losses of CH3*, H2O, CO, C2H2O, and CO2 were observed in the MS/MS spectra. Each of the seven types of flavonoid showed characteristic MS/MS Fragmentation patterns. The isoflavanones, flavanones and chalcones were observed to undergo retro-Diels-Alder Fragmentations. The spectra of almost all the neoflavonoids unexpectedly exhibited only [M-H-CH3]-* radical anions as base peaks without any further Fragmentation. Substitution positions also remarkably influenced the Fragmentation behavior, which could assist in distinction among the flavonoid isomers. The Fragmentation rules deduced here could aid in the characterization of other flavonoids of these types.
Rongxia Liu - One of the best experts on this subject based on the ideXlab platform.
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liquid chromatography electrospray ionization mass spectrometry for the characterization of twenty three flavonoids in the extract of dalbergia odorifera
Rapid Communications in Mass Spectrometry, 2005Co-Authors: Rongxia Liu, Hongzhu Guo, Dean GuoAbstract:A method incorporating high-performance liquid chromatography (HPLC) with electrospray ionization and tandem mass spectrometry, with parallel analysis by HPLC with UV detection using a diode-array detector, was developed for the qualitative characterization of flavonoids in D. odorifera. Twenty-three flavonoids, including six isoflavones, six neoflavones, four isoflavanones, three flavanones, two chalcones, one isoflavanonol and one pterocarpan, were unambiguously identified by comparing their retention times, UV and MS spectra with those of authentic compounds. Furthermore, the collision-induced dissociations of the [M-H]- ions were studied to clarify the MS behavior of the different types of flavonoids. In negative ion ESI-MS all the flavonoids yielded prominent [M-H]- ions in the first order mass spectra. Fragments involving losses of CH3*, H2O, CO, C2H2O, and CO2 were observed in the MS/MS spectra. Each of the seven types of flavonoid showed characteristic MS/MS Fragmentation patterns. The isoflavanones, flavanones and chalcones were observed to undergo retro-Diels-Alder Fragmentations. The spectra of almost all the neoflavonoids unexpectedly exhibited only [M-H-CH3]-* radical anions as base peaks without any further Fragmentation. Substitution positions also remarkably influenced the Fragmentation behavior, which could assist in distinction among the flavonoid isomers. The Fragmentation rules deduced here could aid in the characterization of other flavonoids of these types.
Joseph Banoub - One of the best experts on this subject based on the ideXlab platform.
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gas phase Fragmentation study of a novel series of synthetic 2 oxo 2h benzopyrano 2 3 d pyrimidine derivatives using electrospray ionization tandem mass spectroscopy measured with a quadrupole orthogonal time of flight hybrid instrument
Rapid Communications in Mass Spectrometry, 2009Co-Authors: H Turki, Benoit Genestie, Rachid El Gharbi, Sameh El Boussiry, Joseph BanoubAbstract:The Fragmentation patterns of a series of six novel synthesized benzopyranopyrimidine derivatives 1–6, possessing the same 2-oxo-2H-benzopyrano[2,3-d]pyrimidine backbone structure, were investigated by electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (MS/MS) techniques using a quadrupole orthogonal time-of-flight (QqToF)-hybrid instrument. The series of six pure benzopyranopyrimidine compounds contained three constitutional isobaric isomers (compounds 4–6). A simple methodology, based on the use of ESI (positive ion mode) and increasing the declustering potential in the atmospheric pressure/vacuum interface resulting in collision-induced dissociation (CID), was used to enhance the formation of the product ions. In general, the novel synthetic benzopyranopyrimidine derivatives 1–6 afforded exact accurate masses for the protonated molecules. This led to the confirmation of both molecular masses and chemical structures of the studied compounds. The breakdown routes of the protonated molecules were rationalized by conducting low-energy CID-MS/MS analyses. It was shown that the MS/MS Fragmentation routes for the protonated molecules 1 and 2 were similar, and that the MS/MS Fragmentations of the constitutional isobaric protonated molecules 5 and 6 were identical. It was also shown that the gas-phase CID Fragmentations of 5 and 6 were different from that of their constitutional isomer 4. Finally, the ESI-MS and CID-MS/MS analyses of the protonated molecules that were obtained from the monodeuterated benzopyranopyrimidine derivatives 1–6 confirmed the values obtained for the exact masses, the precise structural assignments of all product ions and all the pathways described in the proposed CID Fragmentations. Copyright © 2008 John Wiley & Sons, Ltd.
Olivier Grovel - One of the best experts on this subject based on the ideXlab platform.
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structural investigation and elucidation of new communesins from a marine derived penicillium expansum link by liquid chromatography electrospray ionization mass spectrometry
Rapid Communications in Mass Spectrometry, 2009Co-Authors: Isabelle Kerzaon, Yves Francois Pouchus, Fabrice Monteau, Bruno Le Bizec, Marierenee Nourrisson, Jeanfrancois Biard, Olivier GrovelAbstract:Penicillium expansum is a ubiquitous species for which there are only few reports for chemical investigation in marine environments. Among thenumerous secondary metabolites produced by this species, communesins represent a new class of cytotoxic and insecticidal indole alkaloids. In this study, we investigated a marine P. expansum strain exhibiting neuroactivity on a Diptera larvae bioassay. Bio-guided purification led to the isolation and the identification of communesin B as the main active compound by HRMS and 1 H and 13 C NMR. Liquid chromatography analyses with detection by electrospray ionization coupled with tandem mass spectrometry (LC/ESI-MS/MS) and high-resolution tandem mass spectrometry (LC/HRMS/MS) allowed the identification and characterization of four other known communesins (A, D, E and F) in the crude extract. A Fragmentation modelfor dimethyl epoxide communesins was proposed after detailed interpretation oftheir MS/MS spectra. Further analyses of the extract using the modelled Fragmentations led to the detection of seven new communesins found as minor compounds. Chemical structural elucidation of these new derivatives is discussed based on their Fragmentation characteristics. Copyright #2009 John Wiley & Sons, Ltd.
James Staunton - One of the best experts on this subject based on the ideXlab platform.
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Fragmentation studies on monensin a by sequential electrospray mass spectrometry
Analyst, 2002Co-Authors: Norberto Peporine Lopes, Christian B W Stark, Paul J Gates, James StauntonAbstract:Monensin A was studied by electrospray ionisation sequential mass spectrometry (ESI-MSn) and all fragments were confirmed by accurate-mass measurements. Analyses were performed on both a quadrupole time-of-flight (Q-tof) and a Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometer. MSn analysis shows that depending on sample preparation the ion at m/z 671 consists of two different ions with the same accurate-mass. It is either the monensin protonated parent ion or a different ion structure derived from the loss of water from the water adduct of monensin. Both ions show different Fragmentation patterns. Major fragment ions from the protonated parent ion were produced by Grob-Wharton type Fragmentations in addition to various simple neutral losses. The Fragmentation pathways of the two different m/z 671 ions are proposed.
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Fragmentation studies on monensin a and b by accurate mass electrospray tandem mass spectrometry
Rapid Communications in Mass Spectrometry, 2002Co-Authors: Norberto Peporine Lopes, Christian B W Stark, Hui Hong, Paul J Gates, James StauntonAbstract:Monensin A and B were studied by electrospray ionisation tandem mass spectrometry (ESI-MS/MS) and the fragment ions were confirmed by accurate-mass measurements. Analyses were performed on both a quadrupole time-of-flight (QTOF) and a Fourier-transform ion cyclotron resonance (FTICR) mass spectrometer. The analysis revealed that fragment ions were produced by Grob-Wharton Fragmentations and pericyclic rearrangements in addition to various simple neutral losses. A study of the protonated and sodiated sodium salt revealed different Fragmentation pathways for these species, thus complementary structural information could be gained. A complete Fragmentation pathway of monensin A and B protonated sodium salt [(M − H + Na) + H]+ and sodiated sodium salt [(M − H + Na) + Na]+ is proposed. MS3 analysis confirmed the separate Fragmentation pathways. Copyright © 2002 John Wiley & Sons, Ltd.
