Some Applications of Mass Spectroscopy

Some applications of mass spectroscopy in inorganic and organometallic chemistry. J. M. Miller and G. L. Wilson, Adv. Inorg. Chem. Radiochem., 1976,18, 229-285 (301). 

Some Applications of Mass Spectroscopy in Inorganic and Organometallic... 

SOME APPLICATIONS OF MASS SPECTROSCOPY IN INORGANIC AND ORGANOMETALLIC CHEMISTRY... 

The application of laser spectroscopy in biology and medicine gained a remarkable importance and is still rapidly growing. Some future aspects of biomolecular laser spectroscopy are already mentioned in the respective chapters. New technologies which combine lasers with conventional instruments, an optical mass spectrometer and a laser ion microscope are discussed by Letokhov 79). 

Chapter 6 describes the concept of hybrid mass spectrometric system with ion attachment technique as ionization method. A combined (hypemated) MS represents time-of-flight (TOP), ion trap quadmpole, ion mobility spectroscopy, ion cyclotron resonance (ICR) or aerosol MS, while descriptions of specially designed inlet system include chromatographic introduction (inlets), and various pyrolysis probes for evolved gas analysis. Some applications of each technology are presented, together with representative and/or illustrative examples. In addition, development of portable lAMS is provided along with explanations and spectral applications. 

In this chapter, we discuss some applications of accurate three-body calculations to baryon spectroscopy. The selection is rather arbitrary we come back to the Gell-Mann-Okubo mass formula and compute the quadrupole moment of the for instance, but do not discuss the magnetic moments. Anyhow, it is interesting to test how far one can push the NRQM to describe the baryon properties. We shall use the handy notation... 

Mass spectroscopy, has, of course, been applied to polymer analysis problems either in conjunction with a prior chromatographic separation or not. In this chapter some non-chromatographic applications of various types of mass spectroscopy are reviewed. Complementary chromatography-mass spectroscopy applications are reviewed in Chapters 3 to 7. 

A number of analytical techniques such as FTIR spectroscopy,65-66 13C NMR,67,68 solid-state 13 C NMR,69 GPC or size exclusion chromatography (SEC),67-72 HPLC,73 mass spectrometric analysis,74 differential scanning calorimetry (DSC),67 75 76 and dynamic mechanical analysis (DMA)77 78 have been utilized to characterize resole syntheses and crosslinking reactions. Packed-column supercritical fluid chromatography with a negative-ion atmospheric pressure chemical ionization mass spectrometric detector has also been used to separate and characterize resoles resins.79 This section provides some examples of how these techniques are used in practical applications. 

An introductory manual that explains the basic concepts of chemistry behind scientific analytical techniques and that reviews their application to archaeology. It explains key terminology, outlines the procedures to be followed in order to produce good data, and describes the function of the basic instrumentation required to carry out those procedures. The manual contains chapters on the basic chemistry and physics necessary to understand the techniques used in analytical chemistry, with more detailed chapters on atomic absorption, inductively coupled plasma emission spectroscopy, neutron activation analysis, X-ray fluorescence, electron microscopy, infrared and Raman spectroscopy, and mass spectrometry. Each chapter describes the operation of the instruments, some hints on the practicalities, and a review of the application of the technique to archaeology, including some case studies. With guides to further reading on the topic, it is an essential tool for practitioners, researchers, and advanced students alike. 

A very common and useful approach to studying the plasma polymerization process is the careful characterization of the polymer films produced. A specific property of the films is then measured as a function of one or more of the plasma parameters and mechanistic explanations are then derived from such a study. Some of the properties of plasma-polymerized thin films which have been measured include electrical conductivity, tunneling phenomena and photoconductivity, capacitance, optical constants, structure (IR absorption and ESCA), surface tension, free radical density (ESR), surface topography and reverse osmosis characteristics. So far relatively few of these measurements were made with the objective of determining mechanisms of plasma polymerization. The motivation in most instances was a specific application of the thin films. Considerable emphasis on correlations between mass spectroscopy in polymerizing plasmas and ESCA on polymer films with plasma polymerization mechanisms will be given later in this chapter based on recent work done in this laboratory. 

Some aspects of the chemistry of helicenes require still more attention. Since the interpretation of the mass spectrum of hexahelicene by Dougherty 159) no further systematic work has been done on the mass spectroscopy of helicenes, to verify the concept of an intramolecular Diels-Alder reaction in the molecular ion. Though the optical rotation of a number of helicenes is known and the regular increase of the optical rotation with increasing number of benzene rings has been shown, the dependence of the rotation on the helicity is still unknown. The asymmetric induction in the synthesis of helicenes by chiral solvents, or in liquid crystals, though small, deserves still more attention because application to other organic compounds will be promoted when the explanation of observed effects is more improved. 

Tunable laser spectroscopic techniques such as laser-induced fluorescence (LIF) or resonantly enhanced multi-photon ionization (REMPI) are well-established mature fields in gas-phase spectroscopy and dynamics, and their application to gas-surface dynamics parallels their use elsewhere. The advantage of these techniques is that they can provide exceedingly sensitive detection, perhaps more so than mass spectrometers. In addition, they are detectors of individual quantum states and hence can measure nascent internal state population distributions produced via the gas-surface dynamics. The disadvantage of these techniques is that they are not completely general. Only some interesting molecules have spectroscopy amenable to be detected sensitively in this fashion, e.g., H2, N2, NO, CO, etc. Other interesting molecules, e.g. 02, CH4, etc., do not have suitable spectroscopy. However, when applicable, the laser spectroscopic techniques are very powerful. 

It may be concluded, from the analysis of the Raman results, that the information provided by Raman spectroscopy is, in essence, similar to that of infrared spectroscopy. The exploitation of the data, namely, the frequencies and intensities due to the molecular vibrations, is of a certain benefit in giving some insight as to the conformations of carbohydrates, and their interactions with the environment. As laser-Raman spectroscopy is applicable to solids, as well as to aqueous solutions, the linear relationship between Raman intensities and mass concentrations, and the specificity and high quality of the spectra experimentally obtained, make this technique particularly promising in investigations of the chemistry and biochemistry of carbohydrates. 

Ethyl acetate is used on the C18-adsorbed anthocyanins to remove polyphenolic compounds. More efficient polyphenolic recovery will be accomplished if residual water is removed from the cartridge with a nitrogen gas stream for 2 to 3 min before application of ethyl acetate. After washing the column with ethyl acetate, water should not be added because some anthocyanins could be eluted and lost. Ethyl acetate removal of polyphenolics is particularly recommended if the anthocyanin fraction is to be subsequently analyzed by electrospray mass spectroscopy. 

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