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.

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

Comparison of Laser (LMS), Californium-252 Plasma Desorption (252Cf-PDMS), Fast Atom Bombardment (FAB), Secondary Ion (SIMS), and Field Desorption (FD) Mass Spectra of a Series of Internal Salts

1987 ◽  
Vol 41 (5) ◽  
pp. 821-829 ◽  
Author(s):  
Kesagapillai Balasanmugam ◽  
Somayajula Kasi Viswanadham ◽  
David M. Hercules ◽  
Robert J. Cotter ◽  
David Heller ◽  
...  
Keyword(s):  
Structure Elucidation ◽  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Negative Ion ◽  
Cluster Ions ◽  
Field Desorption ◽  
Ion Formation ◽  
Plasma Desorption ◽  
Cluster Ion ◽  
Secondary Ion

Comparison of the mass spectral techniques of Laser (LMS), Californium-252 Plasma Desorption (252Cf-PDMS), Secondary Ion (SIMS), Fast Atom Bombardment (FAB), and Field Desorption (FD) Mass Spectrometry is presented for the positive- and negative-ion spectra of a series of internal salts (zwitterions) known as the sultaines. The spectral characteristics compared are: quasimolecular ions, fragment ions and their implication for structure determination, and cluster-ion formation. Quasimolecular ions corresponding to (M + H)+ (all techniques); (M+CH3)+ (LMS, PDMS, SIMS); (M+R)+ (R = long alkyl chain up to C12, LMS); (M+Na)+ (SIMS, 252Cf–PD); (M+Ag)+ (SIMS), (M–H)− (FAB); (M–CH3)−; and (M–R) were observed (negative-ion FD mass spectra were not obtained). Extensive fragmentation is observed for PDMS and LMS, providing the highest level of structural information. Also, the possibilities for structure elucidation by SIMS are very good. Minimal fragmentation is observed for FAB; however, complete structure elucidation is possible by using both the positive- and negative-ion FAB spectra. FD is a less favored technique for the structural analysis of the sultaines. The negative-ion spectra of sultaines obtained by LMS, PDMS, SIMS, and FAB showed identical peaks in the lower mass ranges ( m/z < (M–CH3)−), although of varying intensities. Cluster ions and solvated (glycerol) cluster ions are observed in negative FAB in the higher mass ranges ( m/z > (M–CH3)−). FAB is unique with respect to cluster-ion formation; cluster ions of high order [( nM + H)+, n = 2–14; ( nM?CH3)−, ( nM–R)−, n = 2–9; ( lM+ mG–H)−, l = 1–4, m = 1–3] are observed. Other techniques show cluster ions such as ( nM+H)+, n = 2–3 (SIMS, PDMS, FD); ( nM+Na)+, n = 2 (SIMS and PDMS); and (2M+Ag)+ (SIMS). No cluster ions were observed in LMS.

Synthesis and fast atom bombardment mass spectrometry of the coordination complexes of the ligand 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane

1989 ◽  
Vol 67 (5) ◽  
pp. 797-803 ◽  
Author(s):  
Cindy Lee MacLaurin ◽  
Jack Martin Miller ◽  
Mary Frances Richardson
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Spectroscopic Properties ◽  
Coordination Complexes ◽  
Negative Ion ◽  
Successful Technique ◽  
Negative Ion Mode ◽  
Positive Ion ◽  
Fab Mass Spectra

Metal complexes containing the ligand 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazatetradecane were synthesized and characterized using electron impact (EI) and fast atom bombardment (FAB). The FAB mass spectra were obtained in positive and negative ion mode. FAB in the positive ion mode proved to be the most successful technique for the identification of these compounds. The majority of the FAB spectra obtained were structurally informative, although not all showed molecular (M+) or quasimolecular ([M + H]+) ions. The fragmentations observed were characteristic of the ligands and the metal, and were interpreted based on the chemical and spectroscopic properties of these compounds. Keywords: FAB mass spectroscopy, tetraazacyclotetradecane complexes.

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