Gas-phase proton affinity of deoxyribonucleosides and related nucleobases by fast atom bombardment tandem mass spectrometry

1990 ◽  
Vol 112 (25) ◽  
pp. 9092-9096 ◽  
Author(s):  
Francesco Greco ◽  
Angelo Liguori ◽  
Giovanni Sindona ◽  
Nicola Uccella
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Gas Phase ◽  
Proton Affinity ◽  
Fast Atom Bombardment ◽  
Tandem Mass

Gas-Phase Reactivity of Glycosides and Methyl Glycosides with Cu+, Ag+ and Pb2+ Ions by Fast-Atom Bombardment and Tandem Mass Spectrometry

2001 ◽  
Vol 7 (4-5) ◽  
pp. 321-330 ◽  
Author(s):  
Jean-Yves Salpin ◽  
Laurence Boutreau ◽  
Violette Haldys ◽  
Jeanine Tortajada
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Gas Phase ◽  
Fast Atom Bombardment ◽  
The Other ◽  
Tandem Mass ◽  
Pyranose Ring ◽  
Analytical Potential ◽  
Anomeric Center

The analytical potential of the complexation of three isomeric monosaccharides (D-glucose, D-galactose, D-fructose)and two methyl glycosides ( O-methyl-α-D-glucose and O-methyl-β-D-glucose)by three metal ions, Ag+, Cu+ and Pb2+, has been investigated by fast-atom bombardment (FAB)ionization and tandem mass spectrometry. Our results have shown that the unimolecular reactivity of Ag+ complexes allows the characterization of the C(4)stereochemistry of the pyranose ring, whereas a distinction between D-glucose and D-fructose is not achieved. On the other hand, each of the three [Cu + monosaccharide]+ complexes exhibits specific dissociation patterns. We have also observed that Pb2+ ions induce the richest reactivity and are of particular interest for the identification of the three isomers. Finally, this study has demonstrated that the stereochemistry of the anomeric center of O-methyl-D-glucose is easily determined by reaction with Ag+ or Pb2+ ions. Several mechanisms are proposed to account for the main fragmentations of cationized glucose.

Effects of Internal Hydrogen Bonds between Amide Groups: Gas-Phase Basicity and Proton Affinity of Linear Aliphatic Dicarboxamides

2000 ◽  
Vol 6 (2) ◽  
pp. 97-107 ◽  
Author(s):  
Matthias Witt ◽  
Hans-Friedrich Grützmacher
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Gas Phase ◽  
Proton Affinity ◽  
Conformational Changes ◽  
Maleic Acid ◽  
Kinetic Method ◽  
Tandem Mass ◽  
A Value ◽  
Entropic Effects

The apparent gas-phase basicity GBapp and the proton affinity PA of aliphatic dicarboxamides has been determined by tandem mass spectrometry using the kinetic method. The diamides analyzed are primary maleic acid diamide (1a), fumaric acid diamide (2a) and trans, trans-muconic acid diamide (3a) and the tertiary N,N,N‘,N’-tetramethyl derivatives 2b and 3b, which have an almost fixed relative orientation of the terminal amide groups because of the C–C double bond(s) in the carbon skeleton, and the 1,n-dicarboxamides of succinic acid (4a) and (4b), of glutaric acid (5a) and (5b), of adipinic acid (6a) and (6b) and of sebacinic acid (7a) and (7b) containing a flexible –(CH2) n chain with n = 2, 3, 4 and 8. Very large differences are observed for GBapp derived from the dissociation of proton-bound heterodimers either as metastable ions or by CID for all diamides which are expected to form an internal proton bridge between the carbonyl-O atoms of the terminal amide groups in the protonated species. These effects indicate considerable conformational changes of the diamides by protonation and entropic effects accompanying the dissociation of their proton-bound heterodimers. To study the effect of collisional activation, which is believed to alter the effective temperature, Teff, of the proton-bound dimer ions, on their dissociation, separate experiments have been performed with thermalized proton bound heterodimers of 5a using Fourier transform ion cyclotron resonance (FT-ICR) spectrometry to control the collision energy. The evaluation of Teff from these experiments and the use of Teff in Van't Hoff plots to determine the PA of 5a shows a surprisingly good agreement with the results from tandem mass spectrometry, which supports the view that the kinetic method using different Teff can be used to determine the PA and the difference of the “apparent entropy” of protonation, Δ(Δ SH+) app, of the compound under study and the reference base of the proton bound heterodimer from GBapp even in the case of large entropy effects. The PA of maleic acid diamide 1a and its trans isomer 2a, not building an internal proton bridge by protonation, differ by 80 kJ mol−1. A value of −19 J mol−1 K is obtained for (Δ SH+) app (1a) while entropic effects are essentially absent in the case of 2a. The PA of linear dicarboxamides 4a–7a increases with the length of the –(CH2) n chain and exceeds that of monoamides of a comparable size by 60–100 kJ mol−1. This is attributed to the formation of an internal proton bridge and a release of constraints for the internal proton bridge for the longer chains. Δ(Δ SH+) app is practically constant for 5a–7a at a value of −41 ± 2 J mol−1 K, but only −19 J mol−1 K for 4a. This can be understood if the entropy loss during protonation of the diamides is mostly due to loss of internal rotations of the amide groups. In contrast to the primary amides, the tertiary dicarboxamides 4b–7b display identical PA independent of the length of the –(CH2) n chain, and the effect of formation of the internal proton bridge on the PA is distinctly less than for primary dicarboxamides. In addition, a constant value of only −16 ± 3 J mol−1 K is obtained for Δ(Δ SH+) app of 4b–7b. These results are interpreted by different types of the proton bridges of primary and tertiary diamides. Primary linear dicarboxamides generate a true proton bridge between the carbonyl-O atoms of the terminal amide groups as corroborated by ab initio calculations of their structures. In contrast, protonated tertiary dicarboxamides display properties of (internal) ion/dipole complexes in which the protonated amide group is “solvated” by the second one.

Coaxial continuous flow fast atom bombardment in conjunction with tandem mass spectrometry for the analysis of biomolecules

1989 ◽  
Vol 61 (22) ◽  
pp. 2504-2511 ◽  
Author(s):  
Leesa J. Deterding ◽  
M. Arthur. Moseley ◽  
Kenneth B. Tomer ◽  
James W. Jorgenson
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Continuous Flow ◽  
Fast Atom Bombardment ◽  
Tandem Mass

scholarly journals Fast atom bombardment mass spectra of the .BETA.-blocker nipradilol with nitrate ester group-tandem mass spectrometry (MS/MS) and B/E constant linked scanning.

1990 ◽  
Vol 38 (12) ◽  
pp. 3389-3394 ◽  
Author(s):  
Michiaki YONEDA ◽  
Kazuo TSUJIMOTO ◽  
Mamoru OHASHI ◽  
Masami SHIRATSUCHI ◽  
Yasushi OHKAWA ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Beta Blocker ◽  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Ester Group ◽  
Tandem Mass ◽  
Nitrate Ester
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