The Effect of Metal Atoms on Electron Ionization and Ammonia Chemical Ionization Mass Spectra of Metalloporphyrins: Implications for Geoporphyrin Analysis

2008 ◽  
pp. 84-84-10 ◽  
Author(s):  
BD Beato ◽  
RA Yost ◽  
JME Quirke
Keyword(s):  
Mass Spectra ◽  
Chemical Ionization ◽  
Electron Ionization ◽  
Ionization Mass ◽  
Metal Atoms

Electron ionization and chemical ionization mass spectra of pyridinium and isoquinolinium ylides

1984 ◽  
Vol 19 (6) ◽  
pp. 285-290 ◽  
Author(s):  
D. V. Bowen ◽  
P. W. Skett ◽  
J. Thorpe ◽  
A. O. Plunkett
Keyword(s):  
Mass Spectra ◽  
Chemical Ionization ◽  
Electron Ionization ◽  
Ionization Mass

Electron Ionization and Chemical Ionization Mass Spectra of Some Nα-(t-Butoxycarbonyl)-O-(diorganylphosphono)-L-serines

1992 ◽  
Vol 45 (10) ◽  
pp. 1759 ◽  
Author(s):  
JW Perich ◽  
RB Johns
Keyword(s):  
Thermal Decomposition ◽  
Mass Spectra ◽  
Chemical Ionization ◽  
Electron Ionization ◽  
Ionization Mass ◽  
Major Pathway ◽  
Ethyl Methyl ◽  
The Poor ◽  
Ionization Spectrum ◽  
Chemical Ionization Spectrum

N α -(t- Butoxycarbonyl )-O-( diorganylphosphono )L- serines underwent a complex fragmentation under both electron ionization and chemical ionization ( isobutane ) with the dominant pathway being a function of the phosphono organyl group (phenyl, ethyl, methyl, benzyl, t-butyl). In the case of the phenyl-, ethyl- and methyl-substituted derivatives, both electron ionization (15 eV) and chemical ionization mass spectra showed that β-eliminative loss of the seryl residue was the major pathway, and that the two-step loss of the t- butoxycarbonyl group from the [MH]+ ion was a inor pathway. In the case of the benzyl- and t-butyl-substituted derivatives, the poor mass spectra obtained under electron ionization conditions indicated that extensive thermal decomposition of the sensitive dibenzyl or di-t-butyl phosphate functionality occurred on the heated probe. Under the softer chemical ionization conditions, the mass spectrum of the benzyl-substituted derivative showed that loss of the phosphono benzyl group as the tropylium ion was the major fragmentation, and that both loss of the seryl residue by β-elimination and the cleavage of the t- butoxycarbonyl group were minor events. However, the poor chemical ionization spectrum obtained for the t-butyl derivative indicated that the di-t-butyl phosphate functionality was still sensitive to these milder conditions, with the compound undergoing decomposition on the heated probe.

scholarly journals Discrimination of structural isomers of amphetamine using carbon dioxide negative-ion chemical ionization mass spectrometry

1997 ◽  
Vol 13 (2) ◽  
pp. 151-161 ◽  
Author(s):  
Kevin B. Thurbide ◽  
C. M. Elson ◽  
P. G. Sim
Keyword(s):  
Carbon Dioxide ◽  
Mass Spectra ◽  
Chemical Ionization ◽  
Negative Ion ◽  
Ionization Mass ◽  
Structural Isomers ◽  
Mass Spectral ◽  
Negative Ion Chemical Ionization ◽  
Spectral Behaviour ◽  
Carbon Dioxide Plasma

The negative‒ion chemical ionization mass spectra of a group of structural isomers of amphetamine have been studied using carbon dioxide as the reagent gas. Characteristic and reproducible differences are observed for each member of the set implying that this technique offers a means of distinguishing among groups of amphetamine isomers. Characteristic adducts to the molecular ion are observed in the form (M–[H]+[O]) and (M–[H]+[CO2]). Descriptions of some fragments are given based on the mass spectral behaviour of a set of analogue compounds and the results of oxygen-18 labelled carbon dioxide reagent gas experiments. Contents of the carbon dioxide plasma and their impact on various analytes is also discussed.

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