Collision-induced dissociation mass spectra of protonated alkyl amines

1989 ◽  
Vol 67 (12) ◽  
pp. 2081-2088 ◽  
Author(s):  
Eric J. Reiner ◽  
Alex. G. Harrison ◽  
Richard D. Bowen
Keyword(s):  
Mass Spectra ◽  
Collision Energy ◽  
Low Energy ◽  
Collision Induced Dissociation ◽  
Fragmentation Energy ◽  
Alkyl Amines ◽  
Protonated Amine ◽  
Primary Fragmentation ◽  
Protonated Amines ◽  
Alkane Elimination

The collision-induced dissociation (CID) mass spectra of the [MH]+ ions of a variety of C4 to C6 mono-, di-, and tri-alkyl amines have been determined at 8 keV collision energy and also as a function of collision energy over the range 5–100 eV (laboratory scale). The two major primary fragmentation pathways observed following either mode of activation are (i) production of an alkyl cation by expulsion of ammonia or an alkyl amine, and (ii) formation of a smaller protonated amine by loss of an olefin. In addition, alkane elimination from [MH]+, by a variety of pathways, is a common reaction for protonated dialkyl and trialkyl amines, especially in the 8 keV spectra. However, these alkane elimination reactions are of considerably less importance in the low energy CID spectra because they have high onset energies. The differences observed in the spectra produced by the two methods of activation are discussed in terms of the distributions of internal energies deposited in [MH]+ by the collision process. Keywords: protonated amines, collision-induced fragmentation, energy-resolved mass spectrometry.

Unimolecular fragmentation of some gaseous protonated amines

1986 ◽  
Vol 64 (8) ◽  
pp. 1652-1660 ◽  
Author(s):  
Eric J. Reiner ◽  
Raymond A. Poirier ◽  
Michael R. Peterson ◽  
Imre G. Csizmadia ◽  
Alex G. Harrison
Keyword(s):  
Mass Spectra ◽  
Chemical Ionization ◽  
Ionization Mass ◽  
Potential Energy Profile ◽  
Alkyl Amines ◽  
Alkyl Groups ◽  
Protonated Amines ◽  
Additional Barrier ◽  
Immonium Ions ◽  
Alkane Elimination

The proton-transfer chemical ionization mass spectra of the C3 to C5 monoalkyl amines as well as a number of di- and tri-alkyl amines have been determined using H3+ and (in some cases) HCO+ as protonating agent. The RNH3+ ions fragment to form alkyl ions R+ and eliminate alkenes to form NH4+. In addition, abundant immonium ions are observed in the CI mass spectra corresponding to elimination of alkane from RNH3+ or to direct alkide ion abstraction from RNH2; these ions serve to characterize the alkyl groups attached to the α-carbon atom of the amine. Although alkane elimination from RNH3+ is the thermochemically favoured reaction, only R+ and NH4+ are formed in decomposition of metastable RNH3+ ions. The potential energy profile for fragmentation of i-C3H7NH3+ has been calculated by abinitio molecular orbital methods. These calculations show that CH4 elimination has a large energy barrier additional to the reaction endothermicity while formation of NH4+ has only a small additional barrier and formation of C3H7+ has no barrier additional to the endothermicity. It is concluded that the immonium ions probably arise primarily by direct alkide ion abstraction reactions.

Effect of method of ion preparation on low-energy collision-induced dissociation mass spectra

1986 ◽  
Vol 21 (6) ◽  
pp. 317-319 ◽  
Author(s):  
Sabatino Nacson ◽  
Alex. G. Harrison ◽  
William R. Davidson
Keyword(s):  
Mass Spectra ◽  
Low Energy ◽  
Collision Induced Dissociation ◽  
Energy Collision

ChemInform Abstract: Collision-Induced Dissociation Mass Spectra of Protonated Alkyl Amines

ChemInform ◽  
1990 ◽  
Vol 21 (31) ◽  
Author(s):  
E. J. REINER ◽  
A. G. HARRISON ◽  
R. D. BOWEN
Keyword(s):  
Mass Spectra ◽  
Collision Induced Dissociation ◽  
Alkyl Amines

Tautomerization and Dissociation of Dimethyl Phosphonate Ions(CH3O)2P(H)=O•+:Theory and Experiment in Concert

2001 ◽  
Vol 215 (2) ◽  
Author(s):  
L.N. Heydorn ◽  
Y. Ling ◽  
G. de Oliveira ◽  
J.M.L: Martin ◽  
C. Lifshitz ◽  
...  
Keyword(s):  
Gas Phase ◽  
Mass Spectra ◽  
Low Energy ◽  
Collision Induced Dissociation ◽  
Potential Energy Profile ◽  
Time Resolved ◽  
Gas Phase Chemistry ◽  
Dissociation Chemistry ◽  
Phase Chemistry ◽  
Theory And Experiment

The unimolecular gas phase chemistry of the title ion,(CHThe identity of the ions was probed by tandem mass spectrometry methods. These include MI (metastable ion) or CID (collision induced dissociation) spectra, consecutive MI/CID and CID/CID spectra, NRMS (neutralization-reionization mass spectra), NR/CID and CIDI (collision induced dissociative ionization) spectra, time-resolved CID spectra and deuterium labelling. The energetics of the CHTheory and experiment yield a consistent potential energy profile that describes the isomerization and low energy dissociation chemistry of ions

Distinction between the three disulfide isomers of guanylin 99-115 by low-energy collision-induced dissociation

1998 ◽  
Vol 12 (23) ◽  
pp. 1952-1956 ◽  
Author(s):  
Volker Badock ◽  
Manfred Raida ◽  
Knut Adermann ◽  
Wolf-Georg Forssmann ◽  
Michael Schrader
Keyword(s):  
Low Energy ◽  
Collision Induced Dissociation ◽  
Energy Collision

Differentiation of the Isomeric o-(m- and p-) Nitro-(Chloro- and Bromo-)Benzyl-2,4-(and 2,1-) Disubstituted 2-Thiocytosinium Halides by Electron Impact Ionisation and Fast Atom Bombardment Mass Spectrometry

2009 ◽  
Vol 15 (4) ◽  
pp. 497-506 ◽  
Author(s):  
Tomasz Pospieszny ◽  
Elżbieta Wyrzykiewicz
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Collision Induced Dissociation ◽  
Mass Measurements ◽  
Fragmentation Pathways ◽  
Mass Spectral ◽  
Fragment Ions ◽  
Accurate Mass Measurements ◽  
Impact Ionisation

Electron ionisation (EI) and fast atom bombardment (FAB) mass spectral fragmentations of nine 2,4-(and 2,1-) disubstituted o-( m- and p-)nitro-(chloro- and bromo-)-2-thiocytosinium halides are investigated. Fragmentation pathways, whose elucidation is assisted by accurate mass measurements and metastable transitions [EI-mass spectrometry (MS)], as well as FAB/collision-induced dissociation (CID) mass spectra measurements are discussed. The correlations between the abundances of the (C11H10N4SO2)+1–3; (C11H10N3SCl)+4–6 and (C11H10N3SBr)+7–9 ions and the selected fragment ions (EI-MS), as well as (C18H16N5SO4)+1–3; (C18H16N3SCl2)+4–6 and (C18H16N3SBr2) + 7–9 ions and the selected ions (C7H6NO2)+1–3; (C7H6Cl)+ 4–6; (C7H6Br)+ 7–9 (FAB-MS) are discussed. The data obtained can be used for distinguishing isomers.

Fragmentation of alkoxide ions following collisional activation. An energy-resolved study

1988 ◽  
Vol 66 (11) ◽  
pp. 2947-2953 ◽  
Author(s):  
Roger S. Mercer ◽  
Alex G. Harrison
Keyword(s):  
Kinetic Energy ◽  
Collisional Activation ◽  
Collision Energy ◽  
Relative Importance ◽  
Elimination Reaction ◽  
Proton Abstraction ◽  
Relative Stabilities ◽  
Collisionally Activated Dissociation ◽  
Reaction Channels ◽  
Alkane Elimination

The collisionally activated dissociation reactions of the C2 to C5 alkoxide ions have been studied for collisons occurring at 8 keV kinetic energy and also over the range 5 to 100 eV kinetic energy. The alkoxide ions fragment by 1,2-elimination of H2 and/or an alkane. Thus, primary alkoxide ions fragment by elimination of H2 only, secondary alkoxide ions show elimination of H2 and alkane molecules, while tertiary alkoxide ions show elimination of alkanes only. In alkane elimination, loss of CH4 is much more facilie than loss of larger alkanes. For secondary alkoxide ions, where more than one elimination reaction occurs, the energy dependence of fragmentation has been explored over the collision energy range 5 to 100 eV. The results are interpreted in terms of a step-wise mechanism involving formation of an anion-carbonyl compound ion-dipole complex, followed by proton abstraction by the H− or alkyl anion leading to the final products. The relative importance of the reaction channels is determined by the relative stabilities of these ion-dipole complexes.

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