A study of the positive and negative ion fast atom bombardment mass spectra of α-amino acids

1988 ◽  
Vol 15 (8) ◽  
pp. 419-427 ◽  
Author(s):  
Willem Kulik ◽  
Wigger Heerma
Keyword(s):  
Amino Acids ◽  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Negative Ion

scholarly journals Positive and negative ion mass spectra of flavonoid glycosides by fast atom bombardment.

1988 ◽  
Vol 36 (2) ◽  
pp. 71-80 ◽  
Author(s):  
Akiyo Sakushima ◽  
Sansei Nishibe ◽  
Tadahiro Takeda ◽  
Yukio Ogihara
Keyword(s):  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Negative Ion ◽  
Flavonoid Glycosides

Fast Atom Bombardment Mass Spectra of Some N-α-(t-Butoxycarbonyl)-O-(diorganylphosphono)-L-serines and O-(Diorganylphosphono)seryl-Containing Dipeptides and Tripeptides

1994 ◽  
Vol 47 (2) ◽  
pp. 229 ◽  
Author(s):  
JW Perich ◽  
I Liepa ◽  
AL Chaffee ◽  
RB Johns
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrum ◽  
High Intensity ◽  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Molecular Ions ◽  
Operating Conditions ◽  
Negative Ion ◽  
The Matrix ◽  
Positive Ion

Positive and negative ion fast atom bombardment ( f.a.b .) mass spectrometry were found to be useful methods for the analysis and structural characterization of five Nα-(t- butoxycarbonyl )-O-( diorganylphosphono )-L- serines ( organyl = Ph, Et, Me, Bzl , But), especially in the case of the sensitive benzyl and t-butyl phosphono derivatives. Under positive ion operating conditions, high intensity pseudo-molecular ions were obtained in the f.a.b . mass spectra, and the fragmentation pathway of the phenyl, ethyl and methyl derivatives was established by parent/daughter linked scanning studies to involve (a) the two-step loss of the t- butoxycarbonyl group, (b) loss of the amino acid as the neutral fragment from the [MH]+, [MH-56]+, [MH-100]+ and [MH-146]+ ions by a four- centred β-elimination rearrangement, and (c) cleavage of the phosphono phenyl and ethyl groups from only the [(RO)2P(OH)2]+ and [NH=CHCH2PO3R2+H]+ fragments. Parent/daughter linked scanning studies of the benzyl derivative showed that the prominent fragmentation involved loss of the benzyl group as the tropylium ion and that the 'apparent' [MH-90]+ peak observed in its f.a.b. mass spectrum resulted from cleavage of the phosphono benzyl group in the matrix during the bombardment process. In the case of the t-butyl derivative, parent/daughter linked scanning studies showed that the prominent fragmentation involved successive 'in-flight' loss of the phosphono t-butyl groups as isobutene. Negative ion f.a.b. mass spectrometry of the five derivatives gave f.a.b. mass spectra which displayed distinct [M-H]- anions along with high intensity [M-H-R]- and [(RO)2PO2]- fragment anions, the f.a.b . mass spectrum of the t-butyl derivative containing an additional [M-H-But-But]- fragment anion. Parent/daughter linked scanning studies established that the majority of the observed fragment anions resulted from extensive fragmentation of the Boc -Ser(PO3R2)-OH derivatives in the matrix phase followed by sputtering of the resultant fragments into the gas phase. In addition, positive ion f.a.b . mass spectrometry was found to be useful for the analysis of a series of protected O-( diorganylphosphono ) seryl-containing dipeptides and tripeptides ( organyl = Ph, Et, Me, Bzl ). The obtained spectra showed that β-elimination fragmentation of the Ser(PO3R2) residue was more pronounced with the tripeptide series and indicated that there was increased sensitivity of the O-( diorganylphosphono ) seryl residue with replacement of the Boc group by an amino acyl residue at its N-terminus.

A study of the negative ion FABMS of tris(perfluorophenyl)phosphine and related compounds: matrix effects

1995 ◽  
Vol 73 (8) ◽  
pp. 1321-1328
Author(s):  
Mandapati Saraswathi ◽  
Jack M. Miller ◽  
Tim R.B. Jones
Keyword(s):  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Matrix Effects ◽  
Negative Ion ◽  
The Matrix ◽  
Related Compounds

The mass spectra of tris(perfluorophenyl)phosphine obtained under negative ion Fast Atom Bombardment conditions showed formation of an unusual ion at m/z 397 attributed to ((C6F5)2PO2)−. The matrix effects involved in this reaction are discussed. Negative ion FAB spectra of tris(perfluorophenyl)arsine and tris(perfluorophenyl)stibine are also reported. Keywords: pentafluorophenylphosphine, -arsine, -stibine; negative ion FABMS; matrix effects.

The negative ion mass spectra of (M – H)– ions from phenylthiohydantoin derivatives of amino acids

1995 ◽  
Vol 1 (1) ◽  
pp. 381 ◽  
Author(s):  
Steven Ramsay ◽  
Russell Waugh ◽  
Thomas Blumenthal ◽  
John Bowie
Keyword(s):  
Amino Acids ◽  
Mass Spectra ◽  
Negative Ion ◽  
Derivatives Of

Negative-ion fast-atom bombardment mass spectra of pyrazolylborates with various matrices

1991 ◽  
Vol 5 (3) ◽  
pp. 113-116 ◽  
Author(s):  
Jean-Louis Aubagnac ◽  
Rosa-Maria Claramunt ◽  
Conception Lopez ◽  
José Elguero
Keyword(s):  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Negative Ion

Ligand Exchange in FAB Mass Spectrometry of Monomerie and Dimeric Corrinoids

1984 ◽  
Vol 39 (11) ◽  
pp. 1548-1552 ◽  
Author(s):  
Lutz Grotjahn ◽  
Ludger Ernst
Keyword(s):  
Mass Spectrometry ◽  
Ligand Exchange ◽  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Molecular Ions ◽  
Negative Ion ◽  
Fab Mass Spectrometry ◽  
Fab Mass Spectra

Abstract In the Fast Atom Bombardment (FAB) mass spectra of monomeric and dimeric corrinoids, exchange of metal-bound ligands against matrix particles is observed which leads to pseudo molecular ions. Negative ion FAB mass spectra in particular, give distinct information on the intact molecular units.

The fast atom bombardment mass spectra of some N-substituted pyrimidinium salts

1987 ◽  
Vol 65 (4) ◽  
pp. 718-721 ◽  
Author(s):  
Clement W. Kazakoff ◽  
Robin T. B. Rye ◽  
Oswald S. Tee
Keyword(s):  
Concentration Dependence ◽  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Negative Ion ◽  
Cluster Ions ◽  
Solution Equilibria ◽  
Mixed Cluster ◽  
Cluster Ion ◽  
Conventional Solution ◽  
Positive Ion

The fast atom bombardment mass spectra of selected 1,2-dihydro-1,3-disubstituted-2-oxo-pyrimidinium salts are presented. Loss of N-substituents from the solute cation is the principal fragmentation observed in the positive ion spectra. Several concentration dependent features of the spectra are identified; these are thought to result from the interaction of the solute cation with bombardment-induced matrix fragments. Cluster ions are observed in both positive and negative ion spectra. In a mixed solute system cluster ions resulting from extensive cation and anion mixing are observed; the concentration dependence of these mixed cluster ion peaks can be approximately described in terms of conventional solution equilibria.

scholarly journals Positive and negative ion fast atom bombardment mass spectra of some penicilloic acids.

1984 ◽  
Vol 37 (1) ◽  
pp. 33-43 ◽  
Author(s):  
JOHN LEVESON GOWER ◽  
GERALD D. RISBRIDGER ◽  
MICHAEL J. REDRUP
Keyword(s):  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Negative Ion

Biosynthesis of isochorismate in Klebsiella pneumoniae: origin of O-2

1991 ◽  
Vol 37 (4) ◽  
pp. 276-280 ◽  
Author(s):  
Lolita O. Zamir ◽  
Kenneth A. Devor ◽  
Roy A. Jensen ◽  
Robert Tiberio ◽  
Françoise Sauriol ◽  
...  
Keyword(s):  
Amino Acids ◽  
Natural Products ◽  
Mass Spectra ◽  
Biosynthetic Pathway ◽  
Fast Atom Bombardment ◽  
Claisen Rearrangement ◽  
Aromatic Amino Acids ◽  
Hydroxyl Group ◽  
Chorismic Acid ◽  
Important Branch

The shikimate metabolites are key precursors to a large number of natural products, including aromatic amino acids. Chorismic acid is an important branch point in the biosynthetic pathway to aromatic amino acids. Chorismic acid is also unique among natural products since it is the only compound known to undergo an enzymatic Claisen rearrangement. A metabolite of chorismic acid, isochorismic acid, first observed in Aerobacter aerogenes differs in its chemical structure by the location of the hydroxyl group and the double bonds. Isochorismic acid is a precursor to a growing number of shikimate-derived metabolites. Isochorismic acid has also been postulated to be an intermediate of m-carboxyaromatic amino acids, implying another enzymatic Claisen rearrangement. In this publication, we have isolated isochorismate synthase and found that on lyophilization the enzyme is stable for at least 6 months at −20 °C. Incubation of chorismate with this preparation in water enriched with 18O led to incorporation of one atom of 18O as proven from the fast atom bombardment mass spectra of the HPLC purified derived isochorismate. Key words: chorismate, isochorismate, rearrangement, H218O, isochorismate synthetase.

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