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Titolo:
Relationship between in-source and post-source fragment ions in the matrix-assisted laser desorption (ionization) mass spectra of carbohydrates recorded with reflectron time-of-flight mass spectrometers
Autore:
Harvey, DJ; Hunter, AP; Bateman, RH; Brown, J; Critchley, G;
Indirizzi:
Oxford Glycobiol Inst, Dept Biochem, Oxford OX1 3QU, England Oxford Glycobiol Inst Oxford England OX1 3QU em, Oxford OX1 3QU, England Micromass Ltd, Manchester M23 9LZ, Lancs, England Micromass Ltd Manchester Lancs England M23 9LZ er M23 9LZ, Lancs, England
Titolo Testata:
INTERNATIONAL JOURNAL OF MASS SPECTROMETRY
fascicolo: 1-2, volume: 188, anno: 1999,
pagine: 131 - 146
SICI:
1387-3806(19990517)188:1-2<131:RBIAPF>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
COMPLEX OLIGOSACCHARIDES; SOURCE DECAY; LINKED OLIGOSACCHARIDES; MS;
Keywords:
matrix-assisted laser desorption (ionization) [MALD(I)]; carbohydrates; fragment ions; post-source decay; metastable ions;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
21
Recensione:
Indirizzi per estratti:
Indirizzo: Harvey, DJ Oxford Glycobiol Inst, Dept Biochem, S Parks Rd, Oxford OX1 3QU, England Oxford Glycobiol Inst S Parks Rd Oxford England OX1 3QU ngland
Citazione:
D.J. Harvey et al., "Relationship between in-source and post-source fragment ions in the matrix-assisted laser desorption (ionization) mass spectra of carbohydrates recorded with reflectron time-of-flight mass spectrometers", INT J MASS, 188(1-2), 1999, pp. 131-146

Abstract

The reflectron matrix-assisted laser desorption (ionization) [MALD(I)] mass spectra of many complex carbohydrates (and other compounds) recorded withtime-of-flight (TOF) instruments fitted with time-lag focusing (delayed extraction) contain focused fragment ions resulting from fragmentation withinthe ion source, together with unfocused (metastable) fragments derived from post-source decay. The latter ions are particularly abundant from carbohydrates containing sialic acids as the result of loss of the sialic acid moieties. The relative abundance of these metastable ions was found to decrease with ion-source pulse delay whereas the mass difference between the focused and unfocused ions increased. The mass difference was also found to varywith the instrument used to record the spectra. An equation has been derived that links the masses of the precursor ion with the two fragment ions (focused and unfocused). It contains a term reflecting the geometry of the mass spectrometer and can, thus, be used with any TOF instrument. The formulacan be rearranged such that the mass of an absent molecular ion can be predicted from the masses of the two fragment ion peaks. The metastable ions can also be used to confirm fragmentation pathways in the manner similar to that used for spectra recorded with magnetic sector instruments. Metastableions were also found in spectra recorded with an orthogonal-TOF mass spectrometer using field ionization. The formulae relating the masses of the fragment and precursor ions were also found to apply in this case, further demonstrating their instrument independence. (Int J Mass Spectrom 188 (1999) 131-146) (C) 1999 Elsevier Science B.V.

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Documento generato il 28/11/20 alle ore 21:37:12