Mechanism and structure in chemical ionization mass spectrometry: tricyclic flavanoid compounds

1973 ◽  
Vol 26 (7) ◽  
pp. 1577 ◽  
Author(s):  
JW Clark-Lewis ◽  
CN Harwood ◽  
MJ Lacey ◽  
JS Shannon
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Chemical Ionization ◽  
Ionization Mass Spectrometry ◽  
Chemical Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Fragmentation Pathways ◽  
Fragment Ions ◽  
Metastable Ions ◽  
Fragmentation Patterns

The chemical ionization mass spectra of a series of tricyclic flavanoid compounds have been examined using isobutane and hydrogen as reagent gases and the fragmen- tation modes have been correlated systematically in terms of structure. The technique produces simple fragmentation patterns and abundant metastable ions. The use of deuterium as reagent gas reveals the influence of extraneous water on the spectra and facilitates the interpretation of the fragmentation pathways. The fragment ions appear to arise from isomeric progenitors protonated at different sites in the molecules.

Chemical Ionization Mass Spectrometry of Organophosphorus Insecticides

1974 ◽  
Vol 57 (5) ◽  
pp. 1050-1055 ◽  
Author(s):  
Roy L Holmstead ◽  
John E Casida
Keyword(s):  
Mass Spectrometry ◽  
Electron Impact ◽  
Mass Spectra ◽  
Chemical Structure ◽  
Chemical Ionization ◽  
Ionization Mass Spectrometry ◽  
Chemical Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Organophosphorus Insecticides ◽  
Fragmentation Patterns

Abstract The chemical ionization (CI) mass spectra of 15 important organophosphorus insecticides and 14 of their major metabolites are discussed in relation to the effect of chemical structure on fragmentation patterns. The fragments obtained with CI are sometimes quite different from those formed on electron impact and, in general, simpler spectra are obtained with CI.

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.

Water Chemical Ionization Mass Spectrometry of Aldehydes, Ketones, Esters, and Carboxylic Acids

1986 ◽  
Vol 40 (8) ◽  
pp. 1200-1211 ◽  
Author(s):  
Steven B. Hawthorne ◽  
David J. Miller
Keyword(s):  
Mass Spectrometry ◽  
Carboxylic Acids ◽  
Carbonyl Compounds ◽  
Chemical Ionization ◽  
Ionization Mass Spectrometry ◽  
Chemical Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Deuterated Water ◽  
Alkyl Groups ◽  
Fragmentation Patterns

Chemical ionization mass spectrometry (CI) of aliphatic and aromatic carbonyl compounds using water as the reagent gas provides intense pseudomolecular ions and class-specific fragmentation patterns that can be used to identify aliphatic aldehydes, ketones, carboxylic acids, and esters. The length of ester acyl and alkyl groups can easily be determined on the basis of loss of alcohols from the protonated parent. Water CI provides for an approximately 200:1 selectivity of carbonyl species over alkanes. No reagent ions are detected above 55 amu, allowing species as small as acetone, propanal, acetic acid, and methyl formate to be identified. When deuterated water was used as the reagent, only the carboxylic acids and β-diketones showed significant H/D exchange. The use of water CI to identify carbonyl compounds in a wastewater from the supercritical water extraction of lignite coal, in lemon oil, and in whiskey volatiles is discussed.

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