A major application of tandem mass spectrometry is the study of gas-phase ion chemistry. Gas-phase ion chemistry involving ion thermochemistry and ion dissociation characteristics, is one of the foundations of analytical chemistry. A signal (peak) in a mass spectrum is only identified by its mass-to-charge ratio (m/z) and may represent several isomeric ions. Isomeric species having the same element composition can be distinguished by tandem mass spectrometry. An investigation of isomeric (C,H$\sb3,$N,O) $\sp{+-}$ ions provides such an example, where four isomeric ions ( (H$\sb2$NC(H)O) $\sp{+-}$, (H$\sb2$NCOH) $\sp{+-}$, (H$\sb3$CNO) $\sp{+-}$ and (H$\sb2$CNOH) $\sp{+-}$) and their neutral counterparts were identified by a combination of experimental results and a recent high level ab initio molecular orbital theory calculation. Many elusive neutral species of great interest have been accessed by a tandem mass spectrometric technique, neutralization-reionization mass spectrometry (NRMS), which was developed in the last decade. In this thesis, three oxides of carbon, O=C=C=O, C=C=O and O=C=C=C=O, which have been the object of many studies by experimentalists and theoreticians for almost a century, were first observed as stable neutral species in the gas phase by NRMS. In the gas phase, structures of isomeric species having unique behaviours, such as the two cis and trans isomeric 2-buten-dicarboxylic acids, maleic and fumaric acids, can be defined by full investigations of their molecular ions and major fragment ions. The investigations which involved studies of ion thermochemistry and ion dissociation characteristics as well as the use of isotopically labelled compounds provide more information than an early work which used only conventional mass spectrometric techniques.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/7647 |
| Date | January 1992 |
| Creators | Chen, Hongwen. |
| Contributors | Holmes, J. L., |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Detected Language | English |
| Type | Thesis |
| Format | 190 p. |
Page generated in 0.0022 seconds