FTIR spectroscopy, application

Brooks A.L., Afanasyeva N.I., Makhine V., Bruch R.F., McGregor B., FEW-FTIR Spectroscopy Applications and Computer Data Processing for Noninvasive Skin Tissue Diagnostics In Vivo, SPIE, 1999 3596 140-151. 

Previous mid-IR spectroscopic studies of polymer transitions, with the exception of Enns et al. (42), have used conventional dispersive instruments. One narrow range of the IR spectrum was observed by slowly scanning the frequency as the temperature was varied. Until recently this has been the optimal experimental instrumentation. However, with the advent of the fast Fourier transform algorithm, a new dimension has been added in the form of Fourier transform infrared (FTIR) spectroscopy. Application of this instrumentation to polymer systems has been the subject of recent reviews (58,59). Two texts offer a more in-depth survey of this technique in relation to conventional dispersive spectroscopy (60,61). 

Bikiahis et al (1999) Bikiaris, D. Daniilia, Sister Sotiropoulou, S. Katsimbiri, O. Pavlidou, E. Moutsatsou, A.P Chryssoulakis, Y. Ochre-differentiation through micro-Raman and micro-FTIR spectroscopies application on wall paintings at Meteora and Mount Athos, Greece SpectrochimicaActa. Part A 56 1 (1999) 3-18... 

Another illustrative example of the application of FTIR spectroscopy to problems of interest in adhesion science is provided by the work of Taylor and Boerio on plasma polymerized silica-like films as primers for structural adhesive bonding [15]. Mostly these films have been deposited in a microwave reactor using hexamethyldisiloxane (HMDSO) as monomer and oxygen as the carrier gas. Transmission FTIR spectra of HMDSO monomer were characterized by strong... 

In the following, some examples of applications of Fourier transform infrared (FTIR) Spectroscopy and of solid-state nuclear magnetic resonance (NMR) to the study of polymorphism in polymers are described. 

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. 

Chen Y-X, Ye S, Heinen M, Jusys Z, Osawa M, Behm RJ. 2006c. Application of in-situ ATR-FTIR spectroscopy for the understanding of complex reaction mechanism and kinetics Formic acid oxidation on a Pt electrode at elevated temperatures. J Phys Chem B 110 9534-9544. 

Several modem analytical instruments are powerful tools for the characterisation of end groups. Molecular spectroscopic techniques are commonly employed for this purpose. Nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy and mass spectrometry (MS), often in combination, can be used to elucidate the end group structures for many polymer systems more traditional chemical methods, such as titration, are still in wide use, but employed more for specific applications, for example, determining acid end group levels. Nowadays, NMR spectroscopy is usually the first technique employed, providing the polymer system is soluble in organic solvents, as quantification of the levels of... 

Titration calorimetry and cylindrical internal reflection-Fourier transform infrared (CIR-FTIR) spectroscopy are two techniques which have seldom been applied to study reactions at the solid-liquid interface. In this paper, we describe these two techniques and their application to the investigation of salicylate ion adsorption in aqueous goethite (a-FeOOH) suspensions from pH 4 to 7. Evidence suggests that salicylate adsorbs on goethite by forming a chelate structure in which each salicylate ion replaces two hydroxyls attached to a single iron atom at the surface. 

With the recent progress in Fourier transform infrared (FTIR) spectroscopy, quantitative estimates of the various functional groups can also be made. This is particularly important for application to the higher-molecular-weight solid constituents of petroleum (i.e., the asphaltene fraction). 

Analytically, IR (FTIR) spectroscopy is unquestionably one of the most versatile techniques available for the measurement of molecular species in the laboratory today, and also for applications beyond the laboratory. A major benefit of the technique is that it may be used to study materials in almost any form, and usually without any modification all three physical states are addressed solids, liquids and gases. Also, it is a fundamental molecular property, and as such the information content can be considered to be absolute in terms of information content, and as such can be very diagnostic in terms of material purity and composition. Traces of impurities can be both uniquely detected and in most cases characterized. This is a very important attribute in a process analytical enviromnent. 

Fourier transform infrared (FTIR) spectroscopy of coal low-temperature ashes was applied to the determination of coal mineralogy and the prediction of ash properties during coal combustion. Analytical methods commonly applied to the mineralogy of coal are critically surveyed. Conventional least-squares analysis of spectra was used to determine coal mineralogy on the basis of forty-two reference mineral spectra. The method described showed several limitations. However, partial least-squares and principal component regression calibrations with the FTIR data permitted prediction of all eight ASTM ash fusion temperatures to within 50 to 78 F and four major elemental oxide concentrations to within 0.74 to 1.79 wt % of the ASTM ash (standard errors of prediction). Factor analysis based methods offer considerable potential in mineral-ogical and ash property applications. 

Herres, W. (1987). HRGC-FTIR, Capillary GC, and FTIR Spectroscopy Theory and Applications. New York Huthig. 

Fourier transform methods have revolutionized many fields in physics and chemistry, and applications of the technique are to be found in such diverse areas as radio astronomy [52], nuclear magnetic resonance spectroscopy [53], mass spectroscopy [54], and optical absorption/emission spectroscopy from the far-infrared to the ultraviolet [55-57]. These applications are reviewed in several excellent sources [1, 54,58], and this section simply aims to describe the fundamental principles of FTIR spectroscopy. A more theoretical development of Fourier transform techniques is given in several texts [59-61], and the interested reader is referred to these for details. 

Identification of Intermediates Comparison with EPR Results. The most straightforward application of FTIR spectroscopy in studying the decomposition of UP is to identify reaction intermediates and track their intercon-... 

Studies of the adsorbed odCB phase by C NMR MAS and FTIR spectroscopies were carried out (ref.4). They evidence the occurence of protonated odCB species at the surface and their interaction with Bronsted sites of the catalyst. These features are confirmed by the very good application of the Hammett equation to the isomerisation of p-substituted bromobenzenes (Fig. la). This equation takes the form, log (rate) = constant + trp, in which charge transfer between the initial and the transition states is occuring, the use of cr+is prefered (ref. 16). 

To assess the applicability of FTIR spectroscopy for determining ee values for a given substrate, especially with regard to accuracy, the best position at which isotopes are introduced needs to be determined. For illustration, the lipase- or esterase-catalyzed kinetic resolution of esters is considered here, although the method is not restricted to this type of reaction.13C labeling of carbonyl groups is ideal for several reasons ... 

Chemical and instrumental (e.g., chromatography and mass spectrometry) methods have provided valuable information that lead to the advancement of cheese science. However, these techniques suffer from one or more of the following problems (1) the extensive use of solvents and gases that are expensive and hazardous, (2) high costs, (3) the requirement of specific accessories for different analytes, (4) the requirement of extensive sample preparation to obtain pure and clean samples, and (5) labor-intensive operation. These disadvantages have prompted for the evaluation and adoption of new, rapid, and simple methods such as Fourier-transform infrared (FTIR) spectroscopy. Many books are available on the basics of FTIR spectroscopy and its applications (Burns and Ciurczak, 2001 Sun, 2009). FTIR spectroscopy monitors the vibrations... 

Several new methods and instruments based on infrared spectroscopy are being developed for food applications. Advances in spectroscopic instruments and data analysis have enabled the rapid and nondestructive analysis of cheese parameters in just a few seconds (e.g., Nicolet Antaris FT-NIR by Thermo Electron Corp.). Another recent development is the miniaturization of FTIR instrumentation, which would enable onsite analysis, while the cheese is being produced. The TruDefender FT handheld FTIR by Ahura Scientific, Inc. (Fig. 5.7) is a portable handheld spectrometer that could be applied to food analysis. With numerous developments in FTIR spectroscopy and several potential food analysis applications still unexplored, there is great research potential in this technique that could benefit the industry and research institutions. 

Koca, N., Rodriguez-Saona, L. E., Harper, W. J., and Alvarez, V. B. (2007). Application of Fourier transform infrared (FTIR) spectroscopy for monitoring short-chain free fatty acids in Swiss cheese. J. Dairy Sci. 90, 3596-3603. 

Terahertz pulse spectroscopy was used to observe the polymorphs of ranitidine hydrochloride.91 Sample preparation for this technique is the same as for Raman and FTIR spectroscopy and the data generated is complementary to Raman. Terahertz pulse spectroscopy provides information on the low-frequency intermolecular modes that are difficult to study with Raman due to the proximity of the laser excitation line. The authors concluded that this technique has many applications in pharmaceutical science including formulation, screening and stability studies. 

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