scholarly journals Gas Chromatography Electron Ionization Mass Spectral Analysis of Thio Analogues of Pyrimidine Bases: 5-Bromo-2,4-di-o-(m- and p-) chloro- (bromo-)benzylthiouracils and 6-methyluracils

2012 ◽  
Vol 2012 ◽  
pp. 1-8
Author(s):  
G. Bartkowiak ◽  
E. Wyrzykiewicz ◽  
G. Schroeder
Keyword(s):  
Gas Chromatography ◽  
Electron Ionization ◽  
Gas Chromatography Mass Spectrometry ◽  
Ionization Mass ◽  
Structural Isomers ◽  
Mass Spectral Fragmentation ◽  
Mass Spectral ◽  
Fragment Ions ◽  
Accurate Mass Measurements ◽  
Pyrimidine Bases

Electron ionization (EI) mass spectral fragmentation routes of twelve 5-bromo-2,4-di-o-(m- and p-) chloro- (bromo-)benzyl-thiouracils and 6-methyluracils are investigated. The compounds studied are analyzed using gas chromatography/mass spectrometry (GC/MS). Fragmentation pathways, whose elucidation is assisted by accurate mass measurements and metastable transitions, are discussed. Correlation between the abundances of the selected fragment ions of the compounds investigated is discussed. The data obtained make grounds for distinction of structural isomers.

Gas Chromatographic and Mass Spectrometric Determination of Ametryn and Its N-Dealkylated Products

1984 ◽  
Vol 67 (5) ◽  
pp. 904-909
Author(s):  
Promode C Bardalaye ◽  
Willis B Wheeler ◽  
James L Templeton
Keyword(s):  
Gas Chromatography ◽  
Mass Spectra ◽  
Mass Spectrometric ◽  
Gas Chromatography Mass Spectrometry ◽  
Ionization Mass ◽  
Mass Spectral ◽  
Methane Chemical Ionization ◽  
Electron Impact Mass ◽  
Impact Mass

Abstract Gas chromatographic and mass spectrometric properties of ametryn and its N-dealkylated products were studied to establish the potential use in a recently reported method describing the residue analyses of these compounds by gas chromatography with N-P detection. Electron impact mass spectra show base peaks at the molecular ion (M+), and methane chemical ionization mass spectra give base peaks at (M + 1) ion for all the compounds studied. Characteristic mass spectral fragmentations of ametryn, GS-11354, GS-11355, and GS-26831 are presented. Combined gas chromatography-mass spectrometry rather than gas chromatography alone provides unambiguous residue characterization. The technique also allows quantitation of ametryn and its N-dealkylated products that cochromatograph with interfering materials present in a complex substrate.

Confirmatory Method for Sulfamethazine Residues in Cattle and Swine Tissues, Using Gas Chromatography-Chemical Ionization Mass Spectrometry

1984 ◽  
Vol 67 (1) ◽  
pp. 142-144
Author(s):  
Steven J Stout ◽  
William A Steller ◽  
Arthur J Manuel ◽  
Manfred O Poeppel ◽  
Andrian R Dacunha
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Chemical Ionization ◽  
Negative Ion ◽  
Ionization Mass Spectrometry ◽  
Chemical Ionization Mass Spectrometry ◽  
Gas Chromatography Mass Spectrometry ◽  
Ionization Mass ◽  
Fragment Ions ◽  
Positive Ion

Abstract A gas chromatographic (GC) method has been reported for the determination of sulfamethazine residues in cattle and swine tissues. The extracts from this procedure were found to be directly amenable to examination by gas chromatography–mass spectrometry (GC-MS), allowing positive confirmation of an apparent residue of sulfamethazine. Chemical ionization mass spectrometry (CIMS) was chosen as the MS technique because it generated an ion indicative of intact sulfamethazine and fragment ions indicative of the amine functionality and sulfanil moiety. Positive ion (PI) chemical ionization mass spectrometry was adequate by itself for a confirmatory technique. Negative ion (NI) chemical ionization mass spectrometry alone could not be used for the confirmatory analysis of sulfamethazine, but it did offer a means to check the quantitative data from the positive ion analyses and provided complementary confirmatory data. Satisfactory recoveries were obtained for sulfamethazine in swine and cattle tissues at the tolerance level of 0.1 ppm. Apparent sulfamethazine residues in control tissues were less than 0.01 ppm.

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