Applications of FTIR

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... 

A problem in the application of FTIR to ambient air is that water vapor, C02, and CH4 are all present in significant concentrations and absorb strongly in certain regions of the spectrum. As a result, the spectral regions that are useful for ambient air measurements are 760- to 1300-cm-1, 2000- to 2230-cm-1, and 2390-to 3000-cm l. 

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-... 

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 ... 

Applications of FTIR imaging to complex polymer systems... 

Figure 6.1 Basic concept of the application of FTIR imaging as a high-throughput technique. Placing multiple samples in the field of view of the imaging spectrometer allows the collection of a single dataset that contains information from all samples. Reprinted with permission from ACS.

Applications of FTIR tissue imaging to cervical cancer... 

Loebbecke, C. S., Schweikert, W., Tuercke, T., Antes, J., Marioth, E., Krause, H., Applications of FTIR microscopy for process monitoring in silicon microreactors, in Proceedings of the VDE World Microtechnologies Congress, MICRO.tec 2000 (25-27 Sept. 2000),... 

D. Dolphin and A. Wick, Infrared Absorption Spectroscopy, John Wiley and Sons, 1977. J.R. Durig, Applications of FTIR spectroscopy, Elsevier, 1990. 

The remainder of this paper will describe specific applications of FTIR in support of one of Diamond Shamrock s pesticide programs. All the results described here were obtained from studies of a single compound, thiofanox (P), 3,3-dimethy1-1-methylthio-2-butanone 0-[(methylamino)carbonyl]oxime. Thiofanox is a potent systemic and contact carbamate insecticide. The infrared spectrum of thiofanox is shown in Figure 4. The major peaks in the spectrum are the N-H stretch at 3380 cm-1,... 

The final application of FTIR to be discussed is the analysis of microsamples. A major problem encountered in the infrared examination of microsamples is the reduction in energy reaching the detector (3). The sensitivity of FTIR proved beneficial in work performed in support of metabolite studies of thiofanox. Samples were prepared by dissolving the compound in a small amount of solvent (10-20 pi), followed by withdrawing the solution into a syringe. The tip of the syringe was coated with a small amount of KBr, and the solution was slowly released... 

The C02 assumed in this mechanism of the reduction ofC02on an Hg electrode was detected through an early application of FTIR (Chandresekaran and Bockris, 1987) to Pt in aqueous acetonitrile the mechanism was found to have apathway similar to that in aqueous solutions on Hg and Cu. 

The application of FTIR in chemistry, its unique features, and the relevant instrumentation are well documented [34,35], In brief, an FUR spectrometer is based on a Michelson interferometer that provides a spectrum in the time domain which is Fourier-transformed by a computer to a spectrum in the frequency domain. The sample can be scanned repeatedly, and the accumulated spectra can be averaged, thus producing a representative IR spectrum of a very high signal to noise ratio. This enables the measurement of samples containing a very low concentra-... 

A rather broad applicability of FTIR as a detector in liquid chromatography can be achieved when the mobile phase is removed from the sample prior to detection. In this case the sample fractions are measured in a pure state without interference from solvents. Experimental interfaces to eliminate volatile mobile phases fromHPLC effluents have been tried with some success [133-135] but the breakthrough towards a powerful FTIR detector has only been achieved by Gagel and Biemann, who formed an aerosol from the effluent and sprayed it on a rotating aluminum mirror. The mirror was then deposited in a FTIR spectrometer and spectra were recorded at each position in the reflexion mode [136-138]. 

Griffiths, P.R. (1980) In Analytical Applications of FTIR to Molecular and Biological Systems (Durig, J.R., ed.), Reidel, Holland, p. 11. 

Gazi E, Dwyer J, Lockyer N, Gardner P, Vickerman JC, Miyan J, Hart CA, Brown M, Shanks JH, Clarke N (2004) The combined application of FTIR microspectroscopy and ToF-SIMS imaging in the study of prostate cancer. Faraday Discuss 126 41-59... 

Some applications of FTIR are shown in Figure 7.7. The classic example of using in-line FTIR is the Merck investigation of [5-lactam formation [13]. The reaction was shown to proceed through the ketene intermediate 21. FTIR was also used to determine optimal conditions for the low-temperature alkynylation of the ketone 22 [14] and for the methylation of indole 23 [15]. The conversion of phenol 24 to carbamate 25 and isothiocyanate 26 was conveniendy monitored by FTIR [16] due to the hot temperature and reactive nature of the reaction components, special handling would have been required to withdraw reaction aliquots and prepare samples. 

FTIR spectroscopy exploits infrared (IR) absorption in the mid-IR (400-4000 cm ) region and provides information on the molecular chemistry of materials and interactions (17). IR spectra in this region arise from molecular motions within a chemical bond, and a comprehensive review of the pharmaceutical applications of FTIR can be found elsewhere (18). 

McNaughton, D. and Wood, B.R. (2007) Applications of FTIR imaging in cancer research. Chap. 2 in New Approaches in Biomedical Spectroscopy, Vol. 963 (eds K. Kneipp, R. Aroca, H. Kneipp and E. Wentrup-Byme), ACS Symposium Book Series, Oxford University Press, New York, pp. 14-29. 

Kazarian SG. Application of FTIR spectroscopy to supercritical fluid drying, extraction and impregnation. Appl Spectrosc Rev 1997 32 301-348. 

Rather important work began at Ford Motor Company where in the late 60-ties Weinstock (1969) promoted the importance of OH reactions in the troposphere. In this laboratory Niki used a rather small photoreactor to develop the application of FTIR spectroscopy for quantitative investigation of atmospheric reactions in the laboratory (Niki et al, 1972 Wu et al, 1976 Niki et al, 1981). IR absorption spectroscopy was applied quite early to study chemical reactions of atmospheric interest (Stephens, 1958 Hanst, 1971), based mainly on mirror systems which allowed long path light absorption (White, 1942 1976 Herriott et al, 1964, 1965). However, real progress and success came with the application of modem FTIR spectrometers by Niki et al (1981) and further work in the Pitts group to quantitatively measure rate constants and products in photoreactors by long path FTIR absorption. 

The application of FTIR extinction spectroscopy to study composition and phase changes during a typical AIDA ice nucleation experiment is shown in Figure 4. The left panel shows a series of FTIR extinction spectra recorded during an AIDA expansion experiment... 

The application of FTIR spectroscopy to the analysis of milk has been investigated, and its performance compared to that of conventional filter-based instrumentation [22]. Calibration of the FTIR spectrometer for the determination of fat, protein, lactose, and total solids was performed through the use of PLS. The FTIR method using modified Nicolet 510 research spectrometer was able to provide a four-component analysis of milk in 12 seconds per sample and met the AOAC specifications for milk analysis [22]. The results of this study demonstrated that the use of FTIR spectroscopy would allow payment laboratories to analyse for more components and with appropriate sample handling gain sample throughput speed. A commercial version of an FTIR milk analyser is presently on the market in Europe. An FTIR method for the direct determination of water in milk has also been reported [23]. 

Another potential area of application of FTIR spectroscopy is in the determination of the oxidative status or stability of an oil. Autoxidation is a major deteriorative reaction affecting edible fats and oils, and it is of major concern to processors and consumers from the standpoint of oil quality, as the oxidative breakdown products cause marked off flavours in an oil. A wide range of end products are associated with the autoxidative deterioration of fats and oils, the most important being hydroperoxides, alcohols, and aldehydes. Moisture, hydrocarbons, free fatty acids and esters, ketones, lactones, furans, and other minor products may also be produced, with the free fatty acids becoming more important in thermally stressed oils. In addition, there is significant cis to trans isomerisation and conjugation of double bonds in the hydroperoxides formed as an oil oxidises. 

Other applications of FTIR spectroscopy related to the assessment of the oxidative state of fats and oils are expected to be forthcoming shortly. The evaluation of total carbonyl content is an obvious candidate, and it may also prove possible, through the use of PLS, to estabhsh correlations between... 

At the higher current density, Reaction 1.26 was rate determining. The adsorbed C02 ion present in the mechanism was discovered in the electrode in an early application of FTIR spectroscopy applied to mechanism analysis. 

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