Absorption spectroscopy, application organic compounds

J. R. Dyer, Application of Absorption Spectroscopy of Organic Compounds, Prentice-Hall, Inc., NJ, 1965. 

FIGURE 2.28 (a) The C—H out-of-plane bending vibrations for substituted benzenoid compounds, (b) The 2000- to 1667-cm region for substituted benzenoid compounds (from Dyer, John R., Applications of Absorption Spectroscopy of Organic Compounds, Prentice-Hall, Englewood Cliffs, N.J., 1965). 

FIGURE 19-17 Absorption positions of protons In various stnjctural environments. (Table taken from J. R. Dyer, Applications of Absorption Spectroscopy by Organic Compounds, p. 85, Englewood Cliffs, NJ Prentice-Hall, 1965. With permission.)... 

Crowley, J. I., Harvey III, B., and Rapoport, H. (1973). 7. Macromol. Sci. Chem. 7, 1118. Dyer, J. R. (1965). Applications of absorption spectroscopy of organic compounds. Prentice-Hall, Englewood Cliffs, New Jersey. 

Cells are typically concentrated by filtration and extracted into an organic solvent (usually acetone) after which, pigments are detected by fluorescence or absorption spectroscopy, sometimes after chromatographic separation (Bidigare and Trees, 2000). The application of HPLC to phytoplankton pigment analysis has lowered the uncertainty in the measurement of Chi a and accessory carotenoids, since compounds are physically separated and individually quantified. 

This paper will discuss the use of Near-Edge X-ray Absorption Fine Structure (NEXAFS) Spectroscopy to study the unoccupied n molecular orbital (MO) structures of polymers and polymer-metal interfaces. A collection of systematic NEXAFS and EELS studies of simple organic compounds by J. Stohr and others (1-10) has led to recent advances in the understanding and interpretation of this technique. It s application to complicated polymers and polymer-metal interactions has only begun, but NEXAFS spectroscopy promises to be an important complement to other photoelectron spectroscopies. 

All these theories are now only of historical interest because developments in spectroscopic techniques and the application of the quantum theory and wave mechanics are throwing an entirely new light upon our understanding of the causes of colour. In the first place, spectroscopy has shown that all organic compounds, whether they contain chromophores or not, absorb radiation. The fact that some are coloured is purely fortuitous because it so happens that their strong absorption bands lie within the narrow range of radiation to which the human eye is sensitive. Colour, therefore, is only a special aspect of a general phenomenon. 

Identification of organic compounds by their absorption spectra has become a routine procedure for the past several years. It is a standard practice now , to record either the infra-red or the ultra-violet spectrum while proposing a structure for a new compound or while reporting its physical properties. Electronic absorption spectroscopy has been used as confirmatory evidence for the identity of a previously known substance, just as any other physical property (e.g., melting point, refractive index). Many examples may be cited where a particular structure of a compound was selected from several possibilities on the basis of its ultra-violet or visible spectrum. The high intensity of many of the absorption bands in the near ultra-violet and visible regions not only permits the identification with minute quantities of material, but also serves as an aid in the control of purification of substances. In this book, an attempt has been made to present the basic concepts of electronic spectroscopy and to survey its analytical and structural applications in the different branches of chemistry. 

The two most important analytical applications of IR spectroscopy are the qualitative and quantitative analyses of organic compounds and mixmres. We pointed out at the beginning of this chapter that the frequencies of radiation absorbed by a given molecule are characteristic of the molecule. Since different molecules have different IR spectra that depend on the structure and mass of the component atoms, it is possible, by matching the absorption spectra of unknown samples with the IR spectra of known compounds, to identify the unknown molecule. Moreover, functional groups, such as —CH3, —C=0, —NH2, and... 

The application of stripping voltammetry includes the measurements of metal ions and organic compounds in a variety of chemical, environmental, metallurgical, geological, biological, biochemical, pharmaceutical, and clinical materials [2, 121-123]. They are used in routine trace metal analysis of waters [124] and can serve as reliable, sensitive, and precise methods for the verification of results obtained by atomic absorption spectroscopy, or some chromatographic techniques [125]. 

Overview. Nuclear Magnetic Resonance Spectroscopy Overview Principles. Nuclear Magnetic Resonance Spectroscopy-Applicable Elements Phosphorus-31. Nuclear Magnetic Resonance Spectroscopy Techniques Nuclear Overhauser Effect Multidimensional Proton Solid-State Surface Coil In Vivo Spectroscopy Using Localization Techniques Proteins Overview. Spectrophotometry Organic Compounds. Structural Elucidation. X-Ray Absorption and Diffraction X-Ray Diffraction - Single Crystal. 

See also Atomic Absorption Spectrometry Flame Electrothermal. Atomic Emission Spectrometry Inductively Coupled Plasma. Color Measurement. Forensic Sciences Paints, Varnishes, and Lacquers. Gas Chromatography Pyrolysis. Infrared Spectroscopy Industrial Applications. Liquid Chromatography Size-Exclusion. Paints Water-Based. Spectrophotometry Organic Compounds. X-Ray Absorption and Diffraction X-Ray Diffraction - Powder. X-Ray Fluorescence and Emission Wavelength Dispersive X-Ray Fluorescence Energy Dispersive X-Ray Fluorescence. 

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