Fourier transform infrared matrices

The basic methods of the identification and study of matrix-isolated intermediates are infrared (IR), ultraviolet-visible (UV-vis), Raman and electron spin resonance (esr) spectroscopy. The most widely used is IR spectroscopy, which has some significant advantages. One of them is its high information content, and the other lies in the absence of overlapping bands in matrix IR spectra because the peaks are very narrow (about 1 cm ), due to the low temperature and the absence of rotation and interaction between molecules in the matrix. This fact allows the identification of practically all the compounds present, even in multicomponent reaetion mixtures, and the determination of vibrational frequencies of molecules with high accuracy (up to 0.01 cm when Fourier transform infrared spectrometers are used). 

Ishida, H., Koenig, J.L. (1979). An investigation of the coupling agent/matrix interface of fiberglass reinforced plastic by fourier transform infrared spectroscopy. J. Polym. Sci. Part B. Polym. Phys. Edition 17, 615-626. 

Griffith, D. W. T., and G. Schuster, Atmospheric Trace Gas Analysis Using Matrix Isolation-Fourier Transform Infrared Spectroscopy, J. Atmos. Chem., 5, 59-81 (1987). 

Antoon, M. K., Starkey, K. M., Koenig, J. L. Applications of Fourier Transform Infrared Spectroscopy to Quality Control of the Epoxy Matrix, Composite Materials, Fifth Conference, ASTM, p. 541, 1979... 

One other in situ technique can be used to determine fractional acidity in atmospheric aerosols by means of Fourier transform infrared (FTIR) spectroscopy (46). Originally, impactor samples were collected and were pressed into a KBr matrix, and then the IR spectrum was taken by attenuated total reflectance (ATR) FTIR spectroscopy to determine relative acidity, based on differences in absorption bands for sulfate and bisulfate species. Aerosols with [H+]/[S042 ] ratios greater than 1 could also be qualitatively identified. More recent innovations in the FTIR technique (47, 48) have made possible... 

Several analytical techniques have been used to characterize the polymer/ silane coupling agent interphase. Culler et aL [2] used Fourier transform infrared (FT-IR) spectroscopy to characterize the chemical reactions at the matrix/silane interphase of composite materials. They correlated the extent of reaction of the resin with the coupling agent (as determined by FT-IR) with the extent of interpenetration. Culler et al. [2] have also used observations of improved resistance of the interphase region to solvent attack as indirect evidence to support the interpenetrating network theory. 

SOM, soil organic matter HS, humic substances DH, degree of humification HAC, humic acid C FAC, fulvic acid C TEC, total extractable C HR, humification rate HI, humification index NHC, nonhumified C TOC, total organic C HA, humic acid FA, fulvic acids UV-Vis, ultraviolet-visible FT-IR, Fourier transform infrared NMR, nuclear magnetic resonance ESR, electron spin resonance EEM, excitation-emission matrix. 

Wurrey CJ, Bourne S, Kloepfer RD. 1986. Application of gas chromatography/ matrix isolation/Fourier transformer infrared spectrometry to dioxin determinations. Anal Chem 58 482-483. 

Irradiation (A>295nm, Ar, 10 K) of matrix-isolated (trimethoxysilyl)carbene produced l,l-dimethoxy-l,2-siloxe-tane which was identified by IR spectroscopy in comparison with ab initio calculations at the RHF/6-31G(d,p) level of theory. The most intense IR absorption was observed at 1104 cm-1 <19960M736>. Similarly, vacuum pyrolysis-matrix isolation Fourier transform infrared (FTIR) and DFT studies of 3,3-dimethyl-3-germa-6-oxabicyclo[3.1.0]-hexane indicated the transient formation of dimethylgermoxetane <1998OM5041>. 

K.E. Goeringer and M.W. Ellzy, Analysis of alkylphosphonic acids in environmental waters by gas chromatography/ion trap mass spectrometry and gas chromatography/matrix isolated Fourier transform infrared spectroscopy, in Proc. 1994 ERDEC Sci. Conf. Chem. Biol. Def. Res., D.A. Berg (Ed.), National Technical Information Service, Springfield, 149-155 1996. 

Vibrational spectroscopy is an important tool for the characterization of various chemical species. Valuable information regarding molecular structures as well as intra- and intermolecular forces can be extracted from vibrational spectral data. Recent advances, such as the introduction of laser sources to Raman spectroscopy, the commercial availability of Fourier transform infrared spectrometers, and the continuing development and application of the matrix-isolation technique to a variety of chemical systems, have greatly enhanced the utility of vibrational spectroscopy to chemists. 

Green DW, Reedy GT (1978) Matrix-isolation studies with Fourier transform infrared In Ferraro JR, Basile LJ (eds) Fourier transform infrared spectroscopy - applications to chemical systems, Vol 1 Academic Press, New York, 1-59 Griffiths PR (1975) Chemical infrared Fourier transform spectroscopy Wiley, New York, 340 pp... 

Gurka DF, Brasch JW, Barnes RH, Riggle CJ, Bourne S (1986), Appl. Spectrosc. 40 978-991.. .Micro-diffuse reflectance and matrix isolation Fourier transform infrared techniques for the identification of tetrachlorodibenzodioxins"... 

Following successful recovery of peptide/protein molecule from the microspheres, a simple spectrophotometric method does not always allow discrimination between the monomeric protein form and its aggregates. However, HPLC might separate these species and thus provides more accurate qualitative data [96], But HPLC cannot quantify exclusively the amount of active protein antigen, as is the case with ELISA techniques [97], Nowadays, Fourier transform infrared (FTIR) spectroscopy has become a popular, noninvasive method, as it is able to characterize the secondary structure of entrapped proteins [26, 95, 98-101], Only recently, the integrity of their primary structure was evaluated, thanks to a new matrix-assisted laser... 

Apart from innovative ideas in chemistry, progress in the field of matrix i.solation is closely coupled with the development of new instruments and devices. Fourier-transform infrared instruments have enormously increased the amount of information which is obtained from matrix-isolation experiments. With new helium-cooled infrared detectors and faster Fourier-transform processors, less time is required to obtain high-quality spectra over a large spectral range. Unusual species at low concentrations and isotopic molecules with a low natural abundance can therefore now be detected. Additionally, hidden data are easily accessible by spectra subtraction (e.g., of the spectra before and after photolysis). 

Comparison of several techniques (namely Fourier transform infrared spectroscopy (FTIR), simultaneous thermogravimetric analysis-differential scanning calorimetry (TGA-DSC) and ultrasonic spectroscopy) for assessing the residual physical and mechanical characteristics of polymer matrix composites (PMCs) exposed to excessive thermal loads showed the measured power spectra of ultrasonic energy to correlate with performance of graphite fibre epoxy matrix composites exposed to thermal degradation, and also that analyses with the three techniques all pointed to the same critical temperature at which thermally induced damage increased sharply [58],... 

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