In this project, “selected ion flow tube mass spectrometry” (SIFT-MS), a sensitive analytical technique, reveals potential for the development of applications in the environment and petroleum areas. Many prior applications have shown their potential for analyzing samples in widely disparate areas. Its fast analysis process and high sensitivity gives it a significant advantage over more conventional methods. This project is directed at expanding this technology to more applications in the petroleum and air quality areas. The application to the petroleum industry has shown that SIFT-MS can quantify H2S and CH3SH in natural gas to 11.8 and 1.2 ppbv, respectively. The SIFT-MS results showed a good linear response with increasing sulfide concentrations by using the H3O+ reagent ion to quantify H2S, CH3SH, and the total combined concentration of DMS and C2H5SH. The ability to use the SIFT-MS instrument to trace chemical tracers, such as bromobenzene and chlorobenzene in hydrocarbon mediums, was also investigated. SIFT-MS showed also the capacity to trace these compounds in natural gas and LPG. The limits of detection (LOD) were also obtained. This study furthermore, found the utility of the NO+ reagent ion to analyse qualitatively some of the large hydrocarbons. Unfortunately, however, the SIFT-MS reactions could not distinguish between the structural isomers of these aromatic and aliphatic hydrocarbons and there was probable conflict between the fragmentation product ions with smaller hydrocarbons. From the air quality perspective, the SIFT-MS also proved its potential for use in air monitoring, using passive techniques and particularly for BTEX (benzene, toluene, ethyl benzene, and xylene) compounds. The study illustrated SIFT-MS’s ability to deal with thermal desorption and passive methodology in general. Ecan (Environmental Canterbury) routinely examines environmental pollutants in Christchurch air by passive sampling methodologies. In this study, we compared and achieved agreement by comparing the result of thermal desorption-SIFT-MS (TD-SIFT-MS) of Christchurch air with the more conventional methodologies of TD-GC-MS and the Ecan agency measurements.

Bibliography: leaves 134-148.

Thesis (Ph. D.)--University of Adelaide, 1989. / Includes bibliographical references (leaves 134-148).

Much important work has been done to understand reaction pathways and identify products, yields, and reaction rates for atmospheric oxidation processes. Non-methane hydrocarbons (NMHCs) are the most significant of the organic compounds present in the atmosphere from a chemical perspective and are released into the atmosphere from both natural and anthropogenic sources. The oxidation of these hydrocarbons by hydroxyl radical HO generates products that may themselves be toxic, that play a major role in the formation of photochemical smog, and that to a lesser extent contribute to the formation of acid precipitation. NMHCs have chemical reactivities many times that of methane, the most abundant HC in the atmosphere. However, the atmospheric oxidation processes of less than 50% of atmospheric NMHCs are known. A new experimental technique is needed that can provide insight into atmospheric oxidation products, reaction intermediates, and the relative importance of secondary reaction pathways that follow the initial attack of HO upon a hydrocarbon. The technique should operate at atmospheric pressure to better represent natural reaction processes and conditions, and provide a rapid and direct measure of product identities and yields. In this study we will describe the development and application of a technique that we believe meets these requirements, a technique we call High Resolution Kinetic Atmospheric Pressure Ionization Mass Spectrometry (HRKAPIMS). We begin with the use of atmospheric pressure ionization mass spectrometry in studies of atmospheric oxidation processes. We first describe a potential pitfall in the use of APIMS for the analysis of smog chamber experiments, a common APIMS application, discussing methods to eliminate interference reactions that would otherwise make interpretation difficult. A new experimental approach to the use of APIMS for the analysis of oxidation processes is next described and its use demonstrated. The oxidation of toluene by API source-generated HO produces oxidation products that are protonated and detected by the mass spectrometer. With this approach, we observe all the products found in a variety of previous studies employing a large array of experimental setups and analytical instrumentation. This is significant because our experiments are carried out in a far simpler experimental environment. Toluene is chosen for these experiments because it is an important constituent in polluted urban atmospheres with a complex oxidation mechanism that remains poorly understood. We describe the development of HRKAPIMS, a powerful new approach that allows the simultaneous detection of stable products along with free radical intermediates. The use of nitric oxide to affect product yields is demonstrated, giving valuable insights into reaction kinetics and mechanisms. We also address the theoretical aspects of HRKAPIMS, describing semiempirical calculations to estimate gas-phase basicities for a wide variety of compounds and discuss the errors implicit in this approach. The use of gas-phase basicities is discussed in terms of mass spectrometric analysis and analyte response. Kinetic and thermodynamic modeling is used to address the issues of APIMS and HRKAPIMS sensitivity and response and gain insights into the conditions necessary for linear response and quantitative detection of analytes.

Thesis (Ph. D.)--School of Earth and Atmospheric Sciences, Georgia Institute of Technology, 2004. Directed by L. Gregory Huey. / Includes bibliographical references (leaves 74-89).

No description available.

Thesis (Ph.D.)--York University, 2007. Graduate Programme in Chemistry. / Typescript. Includes bibliographical references. Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR39012

Thesis (Ph. D.)--University of Canterbury, 2009. / Typescript (photocopy). "16 September 2009." Includes bibliographical references (p. [217]-222). Also available via the World Wide Web.

Thesis (Ph.D.)--York University, 2007. Graduate Programme in Physics and Astronomy. / Typescript. Includes bibliographical references (leaves 120-124). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR32065

(EN) The first part of the thesis describes the ionization reactions in the APCI source in the presence (enclosed configuration) and absence (open configuration) of the ion source housing. Commercial APCI source was modified and used in enclosed, as well as open configuration. All other parameters were kept the same (including the source geometry). In the positive mode, the biggest differences were observed for non-polar analytes dissolved in aprotic solvents like toluene, chloroform and carbon disulfide. Protonated species were dominant in the open configuration, while radical cations were mostly present in the enclosed configuration. The excessive protonation in open ion source was caused by the diffusion of water vapor molecules into the ionization region from the atmosphere. Water vapor molecules were also responsible for the formation of an ion [M + 19]+ from alkynes in the open configuration. The fragmentation study confirmed that the ion [M + 19]+ was a 2-methylketone formed by the addition reaction. The formation of such artifacts can pose problems in qualitative analysis. On the other hand, the ion [M + 55]+ was observed in the enclosed ion source as a reaction product of unsaturated compounds with acetonitrile solvent molecules. Its fragmentation can be used for the double bond...