Mass spectroscopy, field-ionization

Field ionization mass spectroscopy of chemically reactive molecular gases found often dissociated species and associated species of these... [Pg.295]

Fig. 8. Field ionization mass spectroscopy envelopes of compound classes in petroleum (Boduszynski et al., 1980).

Boduszynski et al. (70,71), using field ionization mass spectroscopy (FIMS), obtained average molecular weights from 873 to 1231 for the Corbett fractions, with asphaltenes actually the smallest molecules. The VPO value for asphaltenes was over 4000. The values obtained for polar aromatics was 1020 by FIMS and over 1400 by VPO. Results for naphthene aromatics and saturates were quite close by the two methods. It should be realized that the designation of asphaltenes is arbitrary, depending on the precipitating solvent (72,73). Propane precipitates most of the polar aromatics, and pentane asphaltenes can be nearly twice the heptane asphaltenes. [Pg.217]

Various ionization methods were used to bombard phenol-formaldehyde oligomers in mass spectroscopic analysis. The molecular weights of resole resins were calculated using field desorption mass spectroscopy of acetyl-derivatized samples.74 Phenol acetylation was used to enable quantitative characterization of all molecular fractions by increasing the molecular weights in increments of 42. [Pg.408]

F. H. Field, Chemical Ionization Mass Spectroscopy, Accts. Chem. Res. 1,42 (1968). Ion-Cyclotron Resonance Spectroscopy... [Pg.1370]

The pyrolysis of (NSR)4 (R = H, Me) at temperatures above 750°C produces the corresponding sulfur diimides RNSNR according to analysis of the vapors by field ionization mass and photoelectron spectroscopies. ... [Pg.280]

In atomic laser spectroscopy, the laser radiation, which is tuned to a strong dipole transition of the atoms under investigation, penetrates the volume of species evaporated from the sample. The presence of analyte atoms can be measmed by means of the specific interaction between atoms and laser photons, such as by absorption techniques (laser atomic absorption spectrometry, LAAS), by fluorescence detection (laser-induced fluorescence spectroscopy, LIFS), or by means of ionization products (electrons or ions) of the selectively excited analyte atoms after an appropriate ionization process (Figures lA and IB). Ionization can be achieved in different ways (1) by interaction with an additional photon of the exciting laser or of a second laser (resonance ionization spectroscopy, RIS, or resonance ionization mass spectrometry, RIMS, respectively, if combined with a mass detection system) (2) by an electric field applied to the atomization volume (field-ionization laser spectroscopy, FILS) or (3) by collisional ionization by surrounding atoms (laser-enhanced ionization spectroscopy, LEIS). [Pg.2452]

LEIS laser-enhanced ionization spectroscopy FILS field ionization laser spectroscopy RIS resonance ionization spectroscopy RIMS resonance ionization mass spectrometry... [Pg.2454]

H-D. Beckey, Principles of Field Ionization and Field Desorption Mass Spectroscopy, Pergamon Press, New York, NY, USA, 1977. [Pg.302]

Anbar, Determination of Subprogram Amounts of Chemical Agents in the Atmosphere , Edge-woodArs Contract Rept EC-CR-74028, SRI Proj 3122 (1974) ( A method of mass spectroscopy, employing a silicone membrane and field ionization, which involves other new techniques, is presented which is sensitive to picogram amts of chemical agents in the atm)... [Pg.141]