Collision-induced dissociation mass spectra of cocaine, and its metabolites and pyrolysis products

1998 ◽  
Vol 33 (10) ◽  
pp. 961-967 ◽  
Author(s):  
PingPing Wang ◽  
Michael G. Bartlett
Keyword(s):  
Mass Spectra ◽  
Collision Induced Dissociation ◽  
Pyrolysis Products

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.

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

scholarly journals An Organic Chemist’s Guide to Electrospray Mass Spectrometric Structure Elucidation

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 611 ◽  
Author(s):  
Arnold Steckel ◽  
Gitta Schlosser
Keyword(s):  
Atmospheric Pressure ◽  
Structure Elucidation ◽  
Mass Spectra ◽  
Chemical Ionization ◽  
Atmospheric Pressure Chemical Ionization ◽  
Collision Induced Dissociation ◽  
Tandem Mass ◽  
Tandem Mass Spectra ◽  
Pressure Chemical Ionization ◽  
Pressure Chemical

Tandem mass spectrometry is an important tool for structure elucidation of natural and synthetic organic products. Fragmentation of odd electron ions (OE+) generated by electron ionization (EI) was extensively studied in the last few decades, however there are only a few systematic reviews available concerning the fragmentation of even-electron ions (EE+/EE−) produced by the currently most common ionization techniques, electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). This review summarizes the most important features of tandem mass spectra generated by collision-induced dissociation fragmentation and presents didactic examples for the unexperienced users.

The Mass Spectrometry of the Pyrolysis Products of Some Tetraalkylammonium and Bistetraalkylammonium Bromides

1974 ◽  
Vol 52 (19) ◽  
pp. 3438-3443 ◽  
Author(s):  
Ronald E. Verrall ◽  
John A. Burns
Keyword(s):  
Mass Spectra ◽  
Inductive Effect ◽  
Alkyl Halide ◽  
Substitution Reactions ◽  
Pyrolysis Products ◽  
Quaternary Nitrogen ◽  
Tetraalkylammonium Bromide ◽  
Pyrolytic Decomposition ◽  
Major Process ◽  
Positively Charged

The mass spectra of three tetraalkylammonium bromide salts and two series of bistetraalkylammonium bromide salts, one saturated and the other unsaturated, have been studied. Substitution is the major process which occurs in the pyrolytic decomposition of these quaternary ammonium bromides when placed in the probe of the mass spectrometer. This leads to the production of a tertiary amine and an alkyl halide. The substitution reactions which occur are influenced by the proximity of the bromide anion(s) to the positively charged quaternary nitrogen centers in the crystal lattice. As well, a shorter distance between the positive nitrogen centers favors substitution reaction by means of an electron inductive effect.

Structure and fragmentation of C5H11O+ ions formed by chemical ionization

1985 ◽  
Vol 63 (3) ◽  
pp. 609-618 ◽  
Author(s):  
John V. Headley ◽  
Alex. G. Harrison
Keyword(s):  
Proton Transfer ◽  
Mass Spectra ◽  
Chemical Ionization ◽  
Collision Induced Dissociation ◽  
Ionization Mass ◽  
Fragmentation Reaction ◽  
Isotopic Labelling ◽  
Precursor Structure ◽  
Reaction Channels

The proton transfer chemical ionization mass spectra of eleven C5H10O isomers have been obtained using H3+, N2H+, HCO+, and D3+ as reagent ions. The chemical ionization mass spectra in combination with isotopic labelling and metastable ion studies have made it possible to elucidate the major fragmentation reaction channels of the C5H11O+ ions formed and their dependence on precursor structure. From collision induced dissociation studies nine stable distinct C5H11O+ ion structures have been identified; protonated 3-methylbutanone and protonated 2,2-dimethylpropanal readily interconvert by a pinacolic – retro-pinacolic rearrangement.

Formation of C6H7+ ions in ion–molecule reactions in vinyl chloride

1991 ◽  
Vol 69 (12) ◽  
pp. 2038-2043 ◽  
Author(s):  
Jan A. Herman ◽  
Kazimiera Herman ◽  
Terry B. McMahon
Keyword(s):  
High Pressure ◽  
Fourier Transform ◽  
Vinyl Chloride ◽  
Cyclotron Resonance ◽  
Mass Spectra ◽  
Collision Induced Dissociation ◽  
Ion Cyclotron Resonance ◽  
Ion Molecule Reactions ◽  
Step Mechanism ◽  
Ft Icr

The formation of C6H7+ species in ion/molecule reactions in gaseous vinyl chloride was studied in a high pressure photoionization mass spectrometer and in a Fourier transform ion cyclotron resonance (FT-ICR) spectrometer. Collision-induced dissociation (CID) mass spectra of C4H5Cl+, C4H6Cl+, and C6H7+ species suggest a "butadiene-like" structure for the two former ions, and a non-benzenium structure for the last species. The C6H7+ ions are formed in a two-step mechanism involving C4H5+ as intermediate ions. These processes are in competition with condensation reactions leading to the formation of C6H7–9Cl+ species. Key words: ion–molecule reactions, gaseous vinyl chloride, collision-induced dissociation.

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