Identification of desulfoglucosinolates using positive-ion fast atom bombardment mass spectrometry

1988 ◽  
Vol 36 (6) ◽  
pp. 1184-1187 ◽  
Author(s):  
Daniel G. Burke ◽  
Xenophon Cominos
Keyword(s):  
Mass Spectrometry ◽  
Fast Atom Bombardment ◽  
Positive Ion

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.

scholarly journals Analysis of the Core Oligosaccharide ofAeromonas hydrophila(Chemotype III) Lipopolysaccharide Using Fast Atom Bombardment, Electrospray and Low Energy Tandem Mass Spectrometry

1994 ◽  
Vol 12 (2) ◽  
pp. 55-68 ◽  
Author(s):  
Joseph Banoub ◽  
Emmanuel Gentip ◽  
Derek H. Shaw
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Fast Atom Bombardment ◽  
Low Energy ◽  
Tandem Mass ◽  
Core Oligosaccharide ◽  
Molecular Ion ◽  
The Core ◽  
Fragment Ions ◽  
Positive Ion

Fast-atom bombardment mass spectrometry (FAB-MS) was employed for the structural analysis of the core oligosaccharide ofAeromonas hydrophila(Chemotype III) lipopolysaccharide. Positive ion FAB-MS of the underivatized core oligosaccharide gave the protonated molecular ion, confrrming the correct composition in terms of hexoses, heptoses and Kdo which was present as a bicyclic furanosidic lactone. Negative ion FAB-MS gave the deprotonated molecular ion and fragment ions which were derived from more than two cleavage events with charge retention at the reducing and non-reducing terminals. Positive ion F AB-MS of the permethylated core oligosaccharide afforded fragment ions consistent with the defined sequence and branching patterns of the sugar constituents. The electrospray mass spectrum (ESMS) in the positive ion mode of the underivatized core oligosaccharide afforded the protonated molecular ion in the singly and doubly charged forms. Low energy collision-activated dissociation tandem mass spectrometry (CAD MS/MS) analysis of the protonated molecular ion [M+2H]+2provided additional structural data. ESMS of the permethylated and N-acetylated permethylated core oligosaccharides provided useful structural indices and afforded a characteristic pattern for fragmentions resulting from the opening of the methylated bicyclic Kdo furanosidic 1,7- lactone, which was similar to that obtained in the corresponding FAB-MS.

Characterization of metal complexes of 1,10-phenanthroline, 2,2′-bipyridine, and their derivatives by fast atom bombardment mass spectrometry

1989 ◽  
Vol 67 (9) ◽  
pp. 1496-1500 ◽  
Author(s):  
Jack M. Miller ◽  
Kesagapillai Balasanmugam
Keyword(s):  
Mass Spectrometry ◽  
Metal Complexes ◽  
Metal Ion ◽  
Fast Atom Bombardment ◽  
Laser Mass Spectrometry ◽  
Laser Desorption Mass Spectrometry ◽  
Fragment Ions ◽  
Intact Cation ◽  
Singly Charged ◽  
Positive Ion

A series of 1,10-phenanthroline (phen), 5-nitro-1,10-phenanthroline (5-NO2-phen), 2,9-dimethyl- 1,10-phenanthroline (dmp), 2,2′-bipyridine (bpy), and 4,4′-dimethy-2,2′-bipyridine (dmb) metal complexes has been characterized using fast atom bombardment mass spectrometry (FAB MS). Intact cations are observed in the positive ion FAB mass spectra of all tetracoordinated complexes, [Ag(L)2]NO3, [Cu(L)2]2 SO4•5H2O, [Cu(L)2]SO4, and [Tl(L)2](ClO4), where L=bpy, phen, or dmp. Structurally significant fragment ions (ML2+, ML+, M+, and (L+H)+, where M+=metal ion) are also observed. Species such as Ag[Ag(L)2]NO3+, where L=bpy or phen, and Tl[Tl(phen)2](ClO4)+ are also seen. The hexacoordinate complexes, [Co(phen)3]Cl2, [Ru(bpy)Cl2], [Fe(phen)2(CN)2], [Fe(L)3](ClO4), where L=5-NO2-phen, dmb, or bpy, and [Fe(L)3]SO4, where L=bpy or phen, show intact cations in the positive ion spectra; [Ni(bpy)3]X2, where X=Cl−,Br−, NO3−, ClO4−, SCN−, and tartrate2−, and [Co(bpy)3](ClO4) do not. Generally, fragment ions such as ML3+, ML2X+, ML2+, MLX+, and (L+H)+ are observed, where X=singly charged intact anion or HSO4−. Comparison of FAB results with those of laser mass spectrometry (LMS) show that they are comparable, through reduction processes are more important for FAB. LMS always gave the intact cation while FAB was not consistent. Keywords: FAB mass spectrometry, phenanthroline complexes, bipyridine complexes, laser desorption mass spectrometry.

Identification of butyryl derivatives of cyclic nucleotides by positive ion fast atom bombardment mass spectrometry and mass-analysed ion kinetic energy spectrometry

1989 ◽  
Vol 24 (8) ◽  
pp. 679-688 ◽  
Author(s):  
Russell P. Newton ◽  
Terence J. Walton ◽  
Salem A. Basaif ◽  
Andrea M. Jenkins ◽  
A. Gareth Brenton ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Kinetic Energy ◽  
Cyclic Nucleotides ◽  
Fast Atom Bombardment ◽  
Ion Kinetic Energy ◽  
Derivatives Of ◽  
Positive Ion
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