instruments

R spectra of polystyrene film with different x-axis units. (a) Linear in wavenumber (cm -1 ), (b) linear in wavelength (µm).(Reprinted from R. M. Silverstein, G. C. Bassler, and T. C. Morrill, Spectrometric Identification of Organic Compounds, 4th edition. New York: John Wiley & Sons, 1981, p. 166, by permission of John Wiley & Sons, Inc., copyright © 1981.)

R spectra of polystyrene film with different x-axis units. (a) Linear in wavenumber (cm -1 ), (b) linear in wavelength (µm).(Reprinted from R. M. Silverstein, G. C. Bassler, and T. C. Morrill, Spectrometric Identification of Organic Compounds, 4th edition. New York: John Wiley & Sons, 1981, p. 166, by permission of John Wiley & Sons, Inc., copyright © 1981.)

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Schematic diagram of a commercial dispersive IR instrument, the Perkin-Elmer Model 237B Infrared Spectrometer. (Reprinted by permission of the Perkin-Elmer Corporation.)
Simplified optical layout of a typical FTIR spectrometer. (Reprinted by permission of Nicolet Instrument Corporation.)
Schematic diagram of the Nicolet Magna-IR ® 750 FTIR Spectrometer. (Reprinted by permission of Nicolet Instrument Corporation.)
A single-beam IR spectrum of background, showing contribution from trace amount of ambient water and carbon dioxide.

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  • Jeff Hecht Jeff Hecht
  • Donald C. Peckham

In introductory chapters, the author discusses such topics as the evolution of the laser concept, laser theory and principles, methods to enhance laser operation, and accessories that improve laser performance. The heart of the book, however, is devoted to individual laser types. In these chapters, Hecht examines the major and minor kinds of lasers that are commercially available, such as helium-neon, ion, carbon dioxide, chemical, copper vapor, excimer, far-infrared, dye, nitrogen, gallium arsenide, semiconductor diode, and neodymium.

  • Tuan Vo-Dinh

This paper discusses the figures of merit associated with the synchronous luminescence (SL) technique in multicomponent analysis of complex samples. Spectral interferences and experimental factors that influence the choice of experimental conditions are investigated. The efficacy of SL is demonstrated in the direct determination of anthracene and 2-methylanthracene in a raw coal liquid. The application of the second-derivative technique to the SL measurement of organic samples is shown. Special emphasis is directed toward the applicability of the SL technique as a practical and cost-effective screening procedure in the routine analysis of complex organic samples.

  • Randall L. Plant
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Minimally invasive determination of oxygen concentration can be made by measuring phosphorescence lifetime. We describe a technique for depth-resolved measurements of oxygen concentration using confocal imaging of phosphorescence lifetime. A confocal imaging system is used to obtain depth-resolved measurements of phosphorescence decay. The spatial resolution of the system is characterized in terms of the Line Spread Function and shown to be similar in both lateral and depth directions. Lifetimes are calculated with the use of the Rapid Lifetime Determination technique. One- and two-dimensional quantitative images of oxygen concentration in a test specimen are rapidly generated from luminescence decay data. Measurements are made for oxygen concentrations ranging from 2 to 90 μM. A linear relationship between Pdmeso-tetra-(4-sulfonato-phenyl)-porphine phosphorescence inverse lifetime and oxygen concentration is determined. The presence of an intervening solution of different oxygen concentration does not significantly affect the concentration measurements made with the use of depth-resolved imaging techniques.

  • Jonathan P. Blitz

Silica gel surface structures resulting from silylation, thermal treatment and reaction with TiCl4 have been investigated by variable temperature diffuse reflectance FT-IR spectroscopy. The surface selectivity of the diffuse reflectance technique provides the capability of obtaining useful information in regions of strong silica absorptions by spectral subtraction. Singly and doubly bonded surface titanium groups are identified. With knowledge of silica gel surface structure after silylation and/or thermal treatments, it is possible to synthesize predominantly singly or doubly bonded titanium surface species. The approach described should be generally applicable for a variety of surface modification reactions.

  • J. Throck Watson
  • Klaus Biemann

A technique for the recording of complete high resolution mass spectra (resolving power: 1 part in 10 000 or better) of compounds emerging from a gas chromatograph is discussed. The pressure reduction system used for the connection of chromatographic column and mass spectrometer is short, simple in design, and made entirely of glass which make it suitable for the study of complex, polar, and high-boiling compounds. The quality and magnitude of mass spectral data obtainable by this technique demonstrate the value it will have in the identification or determination of the structure of compounds separated by gas chromatography. (C) 1965 American Chemical Society.