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Main Fragmentation Pathways (main + fragmentation_pathway)
Selected AbstractsElectrospray tandem mass spectrometry of lexitropsinsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2001M. Rosário M. Domingues Several compounds, representative of the class of lexitropsins, were analyzed by electrospray tandem mass spectrometry. The study of the fragmentations of the protonated molecular species ([M,+,H]+) and of selected fragment ions allowed proposals for the main fragmentation pathways of compounds of this type. The interpretation of the fragmentation pathways of these compounds was complicated because of intramolecular hydrogen migration. In order to better understand the fragmentation pathways, the MS/MS/MS spectra of several compounds, and the MS/MS and MS/MS/MS spectra of the deuterated compounds, were obtained. Accurate mass measurements helped elucidate the structures of smaller fragment ions. Low-energy collision-induced decomposition (CID) tandem mass spectrometry of lexitropsins with electrospray ionization has proven to be a good method for the structural characterization and identification of this class of compounds. Main fragmentation pathways occur by cleavage of the peptide bond followed by the elimination of the substituted pyrrole ring, and their elucidation will facilitate structural characterization of new lexitropsins. Copyright © 2001 John Wiley & Sons, Ltd. [source] Photoionization studies on various quinones by an infrared laser desorption/tunable VUV photoionization TOF mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 12 2008Yang Pan Abstract Photoionization and dissociative photoionization characters of six quinones, including 1,2-naphthoquinone (1,2-NQ), 1,4-naphthoquinone (1,4-NQ), 9,10-phenanthroquinone (PQ), 9,10-anthraquinone (AQ), benz[a]- anthracene-7,12-dione (BAD) and 1,2-acenaphthylenedione (AND) have been studied with an infrared laser desorption/tunable synchrotron vacuum ultraviolet (VUV) photoionization mass spectrometry (IR LD/VUV PIMS) technique. Mass spectra of these compounds are obtained at different VUV photon energies. Consecutive losses of two carbon monoxide (CO) groups are found to be the main fragmentation pathways for all the quinones. Detailed dissociation processes are discussed with the help of ab initio B3LYP calculations. Ionization energies (IEs) of these quinones and appearance energies (AEs) of major fragments are obtained by measuring the photoionization efficiency (PIE) spectra. The experimental results are in good agreement with the theoretical data. Copyright © 2008 John Wiley & Sons, Ltd. [source] Electrospray ionization tandem mass spectrometric characteristics of d4T H-phosphonate and distamycin conjugatesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2009Jingjing Ding The study of the dissociation of the protonated molecular species [M+H]+ and selected fragment ions allowed proposals for the main fragmentation pathways of the title compounds. The main fragments are formed by expelling a molecule of thymine, thymidine (d4T) or isopropyl. The most striking feature of the tandem mass (MS/MS) spectra is the cleavage of CCO bonds between N -methylpyrrole and carbonyl groups in the presence of the amidine. Electrospray ionization is proven to be a good method for the structural characterization and identification of these kinds of compounds. Copyright © 2009 John Wiley & Sons, Ltd. [source] Electrospray tandem mass spectrometry of lexitropsinsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2001M. Rosário M. Domingues Several compounds, representative of the class of lexitropsins, were analyzed by electrospray tandem mass spectrometry. The study of the fragmentations of the protonated molecular species ([M,+,H]+) and of selected fragment ions allowed proposals for the main fragmentation pathways of compounds of this type. The interpretation of the fragmentation pathways of these compounds was complicated because of intramolecular hydrogen migration. In order to better understand the fragmentation pathways, the MS/MS/MS spectra of several compounds, and the MS/MS and MS/MS/MS spectra of the deuterated compounds, were obtained. Accurate mass measurements helped elucidate the structures of smaller fragment ions. Low-energy collision-induced decomposition (CID) tandem mass spectrometry of lexitropsins with electrospray ionization has proven to be a good method for the structural characterization and identification of this class of compounds. Main fragmentation pathways occur by cleavage of the peptide bond followed by the elimination of the substituted pyrrole ring, and their elucidation will facilitate structural characterization of new lexitropsins. Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||