Infrared Spectroscopy, Fonrier transform

S. J. Choqnette, J.C. Travis, L.E. O Neal, C. Zhn, and D.L. Dnewer, SRM 2035 a rare earth oxide glass for the wavelength calibration of near infrared dispersive and Fonrier transform spectrometers. Spectroscopy, 16(4), 14—19... 

Andms, P. G., and Strickland, R. D. 1998. Cancer grading by Fonrier transform infrared spectroscopy. Biospectroscopy 4 37M6. 

The introduction of in-situ infrared spectroscopy to electrochemistry has revolutionised the study of metal/electrolyte interfaces. Modnlation or sampling techniques are applied in order to enhance sensitivity and to separate snrface species from volume species. Methods such as EMIRS (electrochemicaUy modulated IR spectroscopy) and SNIFTIRS (subtractively normalised interfacial Fonrier Transform infrared spectroscopy) have been employed to study electrocatalytic electrodes, for example. There have been surprisingly few studies of the semiconductor/electrolyte interface by infrared spectroscopy. This because up to now little emphasis has been placed on the molecnlar electrochemistry of electrode reactions at semiconductors because the description of charge transfer at semiconductor/electrolyte interfaces is derived from solid-state physics. However, the evident need to identify the chemical identity of snrface species should lead to an increase in the application of in-situ FTIR. 

FIGURE 27.2 Comparison of conversion versns time for the reaction of Scheme 27.1 using high-performance liqnid chromatography (HPLC) sampling of prodnct concentration to in situ monitoring by Fonrier transform infrared (FTIR) spectroscopy and reaction calorimetry. 

The final step in the synthesis of 9 is the saponification of the ester in 16, followed by precipitation by acidification, and filtration (Scheme 4.3). Although HCl was used for this purpose when 9 was made in-honse, the vendor utilized acetic acid. The by-product of this transformation is potassinm acetate and conld be a potential contaminant in 9. Further support for this hypothesis was garnered by analysis of the filtrate obtained after washing the implicated batch of 9 with water and methanol, which revealed the presence of potassinm (by qualitative elemental x-ray microanalysis) and acetate (by Fonrier transform infrared [FT-IR] spectroscopy). ICP (inductively coupled plasma) tests did not show the presence of any other ioific impurities at significant levels. 

Urban and co-workers [82] stndied the strncture of styrene-acrylic acid copolymers using attenuated total reflection Fonrier transform infrared spectroscopy. Kandu and El Gamel [83] correlated the relative intensities of the carbonyl frequencies of the methyl acrylate units in styrene methyl acrylate copolymers with copolymer composition. The positions and shapes of the carhonyl hands in the infrared absorption spectra of the copolymers dissolved in chloroform, were shown to depend on the composition of the copolymers and upon the presence of different proportions of methyl acrylate centred triads. The results obtained by infrared spectroscopy were compared with those obtained by C-NMR. Infrared spectra may be used to yield information about both the copolymer composition and the triad sequence distribution. 

Fourier transform near-infrared spectroscopy had been used to determine traces of hydroxy and carboxy fnnctional groups and water in polyesters. Bowden and co-workers [106] monitored the degradation of PVC using Raman microline focus spectrometry. They demonstrated that PVC decomposition is accompanied by the formation of modal polyene chains containing 11-12 or 13-19 double bonds. Bloor [107] has discnssed the Fonrier transform Raman spectroscopy of polydiacetylenes. Koenig [108] discnsses resnlts obtained by the application of infrared and Raman spectroscopy to polymers. 

Wessel E, Vogel C, Siesler HW. Fonrier transform infrared imaging spectroscopy of the diffnsion process of DjO into polyamide 11. Appl Spectrosc 2009 63 1-5. 

Various workers have studied the application of Fonrier-transform infrared spectroscopy (FTIR) to determine diffusion coefficients of mostly water vapour, in various polymers [17-20]. In particnlar, the work of Lagaron [16] is discnssed next. 

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