Date of Award
Master of Science
The main objectives of this investigation were three fold: (1) to design and fabricate a heated inlet system for the mass spectrometer; (2) to obtain the mass spectra of the major tobacco alkaloids under normal operating conditions; and ( 3) to determine the ionization potentials of the alkaloids as well as the appearance potentials of some of the major fragment ions derived from the alkaloids.
The mass spectrometer is designed to analyze only materials in the vapor state . Since some materials do not exert sufficient vapor pressure at room temperature under reduced pressure to be analyzed directly, it is necessary to heat these materials before the analysis is possible. The tobacco alkaloids are among the many organic compounds which cannot be analyzed maaa spectrometrically at room temperature and at a pressure of l X 10 -6 mm. of Hg. or higher. Since this is the case, a suitable heated inlet must be improvised in order to vaporize the alkaloids. From the mass spectrum of the alkaloid, it is then possible to arrive at a positive identification of the material if it is present in a sample of unknown composition.
The ionization potential of a molecule is simply an additional physical constant similar to a boiling point, melting point, etc. Generally speaking, it cannot be used as a direct method of identification, but it can serve as an additional parameter for substantiating the proposed structure of a compound. The appearance potential of a fragment ion may lend itself useful in determining such entities as bond energy and heat of formation.
Kuhn, William Frederick, "Mass spectra correlations and the appearance potentials of the major tobacco alkaloids" (1962). Master's Theses. 185.