A VERY HIGH YIELD ELECTRON IMPACT ION SOURCE FOR QUADRUPOLE MASS SPECTROMETRY.
AuthorKOONTZ, STEVEN LOWELL
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractOperational characteristics and performance of two mass spectrometers incorporating improved versions of the Very High Yield Electron Impact (VHY-EI) ion source are described. The ionizers are designed around a large volume, low pressure, hot cathode Penning geometry and operate at source pressures of 10⁻⁵ torr and below. In combination with low spherical aberration focusing optics, mass analyzed ion currents 100 to 1000 times more intense than those produced by conventional ionizers operated under identical or comparable conditions of resolution, analyzer type, sample pressure, and electron impact energy are obtained. In addition, high ionization-mass analysis efficiencies have been demonstrated for a variety of organic compounds with sample mass flow rates approaching 1 mg/min. Typical electron impact spectra are obtained with no evidence of pyrolysis or ion molecule reactions. Unusually intense spectra can be produced with low energy electrons.