Field ionization mass spectrometry

Abstract

Field ionization and field desorption are described and distinguished. Field ion and field desorption emitters of various types are available, and activation processes for these emitters have been devised. Ion sources and mass spectrometers for field ionization, and the mass spectra produced, are discussed. The investigation of surfaces and surface processes by field ionization mass spectrometry is considered, and the importance of chemical reactions on the emitter surface is emphasized. Field ionization can be used to investigate the kinetics and mechanisms of ionic dissociation reactions. The uses of field ionization mass spectra for analytical and structural investigations are briefly summarized.

Anisotropic Molecular Ionization at 1 V from Tellurium Nanowires (Te NWs)

“…Creation of molecular ions using the high electric fields associated with the application of electrical potentials to small objects is embodied in the methods of field ionization (FI) and field desorption (FD) mass spectrometry. , These ionization methods, although still in use, inconveniently involve unit operations in a vacuum. The development of ambient ionization methods which employ unmodified samples in the open air − has led to ionization from solutions on paper substrates − by application of voltages in the low kV range.…”

Field ionization-field desorption source for nonfragmenting mass spectrometry

“…This report describes the use of stable isotopes and direct sample insertion chemical ionization mass spectrometry (CIMS) to study these aspects of the metabolism of the psychotomimetic amine l-(2,5,-dimethoxy-4-methylphenyl)-2-aminopropane (1) (2) by the 10000 X g supernatant and microsomal fractions obtained from rabbit liver. This compound, first described in 1969 (3), has been reported to be one of the most potent of a known series of l-phenyl-2aminopropanes. Racemic 1 is 80 times more active than mescaline in man (3).…”

“…In view of the stereoselective biological activity demonstrated for amine 1, we have investigated the extent to which the metabolism of 1 is influenced by the configuration about the asymmetric center of the 2-aminopropyl side chain through the use of isotopically labeled resolved substrates and CIMS analysis. Additionally, we have characterized and quantified mass spectrometrically several in vitro metabolites of 1 as part of an effort to evaluate the possible role (3,8) of these substances in the overall pharmacological activity of the parent drug. Information on deuterium isotope effects associated with the formation of some of these metabolites has also been gained.…”

“…Field ionization has drawn considerable interest in recent years because of its ability to produce primarily unfragmented mass spectra (1)(2)(3). The analytical applications of this technique have been described before (1-3).…”