Fourier transform infrared 100% line

Co concentration was determined by spectrophotometer (Varian Cary 500) at 692 nm wave length, with the sample diluted with a 9 mol/L concentrated HCl solution. NO content in gas phase was obtained by an on-line Fourier transform infrared spectrometer (Nicolet E.S.P. 460 FT-IR) equipped with a gas cell and a quantitative package, Quant Pad. 

Fourier-transform infrared (IR) spectra (resolution 2 cm- ) were recorded with a Perkin Elmer 1750 instrument in a quartz cell connected to grease-free evacuation and gas manipulation lines. The self-supporting disk technique was used. Before recording the spectra, the samples were treated with O2 at 450°C (Ih), then cooled down to r.t. before evacuating the O2. The sample was then evacuated at 400°C. Evacuation at higher temperatures lead to a drastic cut off of IR trasparency. All reactants were purified prior to the adsorption experiments. Due to the better resolution of the spectra, only results for Sb V=1.0 are reported here, however the IR data for Sb V=3.0 were not significantly different. 

At present, most workers hold a more realistic view of the promises and difficulties of work in electrocatalysis. Starting in the 1980s, new lines of research into the state of catalyst surfaces and into the adsorption of reactants and foreign species on these surfaces have been developed. Techniques have been developed that can be used for studies at the atomic and molecular level. These techniques include the tunneling microscope, versions of Fourier transform infrared spectroscopy and of photoelectron spectroscopy, differential electrochemical mass spectroscopy, and others. The broad application of these techniques has considerably improved our understanding of the mechanism of catalytic effects in electrochemical reactions. 

Ludlow, M., Louden, D., Handley, A., Taylor, S., Wright, B., and Wilson, I.D., Size-exclusion chromatography with on-line ultraviolet, proton nuclear magnetic resonance, and mass spectrometric detection and on-line collection for off-line Fourier transform infrared spectroscopy, /. Chromatogr. A, 857,89,1999. 

The infrared spectra of the different samples were taken with a Fourier Transform infrared spectrometer (Digilab FTS-14) using the double beam mode vs. air as reference. 150 scans per sample and 100 scans per reference, at a resolution of 4 cm-l, were taken for every sample. All spectra were stored on tape, and a digital substraction of the after- and- before UV exposure (or any other sample treatment) spectra was performed, whenever needed, by an on-line computer, thus permitting a better visualization of the spectral changes in the polymer by UV- photooxidation. 

Always based on the use of IR spectrophotometry, a novel attenuated total reflection-Fourier-transform infrared (ATR-FTIR) sensor [42] was proposed for the on-line monitoring of a dechlorination process. Organohalogenated compounds such as trichloroethylene (TCE), tetrachloroethylene (PCE) and carbon tetrachloride (CT) were detected with a limit of a few milligrams per litre, after extraction on the ATR internal-reflection element coated with a hydro-phobic polymer. As for all IR techniques, partial least squares (PLS) calibration models are needed. As previously, this system is promising for bioprocess control and optimization. 

Another similar study of crystallization was performed where on-line ATR-FTIR spectroscopy was used to provide concentration information, however on-line diffuse reflectance Fourier-transform infrared... 

Fourier-transform infrared (FT-IR) spectra (resolution 2 cm" ) were recorded with a Perkin-Elmer 1750 instrument in a cell connected to grease-free evacuation and gas manipulation lines. The self-supporting disk technique was used. The usual pretreatment of the samples was evacuation at 500 C. 

Figure 23-3 Infrared absorbance spectra of the amide regions of proteins. (A) Spectra of insulin fibrils illustrating dichroism. Solid line, electric vector parallel to fibril axis broken line, electric vector perpendicular to fibril axis. From Burke and Rougvie.24 Courtesy of Malcolm Rougvie. See also Box 29-E. (B) Fourier transform infrared (FTIR) spectra of two soluble proteins in aqueous solution obtained after subtraction of the background H20 absorption. The spectrum of myoglobin, a predominantly a-helical protein, is shown as a continuous line. That of concanavalin A, a predominantly (3-sheet containing protein, is shown as a broken line. From Haris and Chapman.14 Courtesy of Dennis Chapman.

Combination of static subcritical water extraction and solid-phase microextraction Comparison of CHC1F2, N2O and CO2 extractants. CHC1 F2 gave highest recovery, methanol-modified CO2 gave 90% recovery Combination of supercritical fluid extraction with off-line Fourier transform infrared spectroscopy... 

Variations in organic structure of vitrinite concentrates were determined with Fourier transform infrared spectroscopy (FTIR). FTIR is a relatively new method for obtaining quantitative data from the organic constituents of coal and provides spectra of greater quality than conventional infrared spectrometers. The system employs an on-line minicomputer which enables the user to analyze data and perform a variety of mathematical manipulations. 

Filipelli, M., F. Baldi, and J.H. Weber. 1992. Methylmercury determination as volatile methylmercury hydride by purge and trap gas chromatography in line with Fourier transform infrared spectroscopy. Environ. Sci. Technol. 26 1457-1460. 

The use of an on-line Fourier transform infrared (FTIR) detector with GC has allowed for the identification of unknowns and the distinction between structurally similar compounds. Many compounds with structural similarities cannot be identified by electron impact mass spectrometry because the fragmentation patterns are (or are nearly) identical. An example is the identification of positional isomers of substituted chlorobenzenes, whose mass spectra are identical. In these cases, chemical ionization can be used to highlight structural differences. The infrared detector (IRD) gives quite different spectra for positional isomers, and when compared to library spectra of authentic compounds, it gives unequivocal identification. 

Fig. 1. (a) THz absorption spectra from Kemp et al. [38]. (b) Comparison study of transmission spectra of RDX using THz-TDS and Fourier Transform Infrared (FTIR) spectroscopy with data from Kemp et al. and Huang et al [39]. The dashed line is RDX from Kemp et al. The other curves are from Huang et al., where the bottom curve is RDX measured by THz-TDS, the solid curve is RDX measured by FTIR, and the top curve... 

In the author s opinion, the better approach to experimentally study the morphology of the silica surface is with the help of physical adsorption (see Chapter 6). Then, with the obtained, adsorption data, some well-defined parameters can be calculated, such as surface area, pore volume, and pore size distribution. This line of attack (see Chapter 4) should be complemented with a study of the morphology of these materials by scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning probe microscopy (SPM), or atomic force microscopy (AFM), and the characterization of their molecular and supramolecular structure by Fourier transform infrared (FTIR) spectrometry, nuclear magnetic resonance (NMR) spectrometry, thermal methods, and possibly with other methodologies. 

Modern NIR equipment is generally robust and precise and can be operated easily by unskilled personnel [51]. Commercial instruments which have been used for bioprocess analyses include the Nicolet 740 Fourier transform infrared spectrometer [52, 53] and NIRSystems, Inc. Biotech System [54, 55]. Off-line bioprocess analysis most often involves manually placing the sample in a cuvette with optical pathlengths of 0.5 mm to 2.0 mm, although automatic sampling and transport to the spectrometer by means of tubing pump has been used (Yano and Harata, 1994). A number of different spectral acquisition methods have been successfully applied, including reflectance [55], absorbance [56], and diffuse transmittance [51]. 

Many other on-line detectors suitable for SEC columns as reviewed [154], including chemiluminescent nitrogen detection, dynamic surface tension detection, high frequency detection and Fourier transform infrared detection, can be applied to FFF the latter being capable of delivering polymer compositions online. 

Improvements in column technology, detector sensitivity and the development of new detection systems, have made possible the routine separation of picomole quantities of nucleic acid components in complex physiological matrices. The very sensitivity of most LC systems, however, which is invaluable in the analysis of biological samples, is often the limiting factor because of inadequate or ambiguous identification methods. Although tremendous advances have been made in the on-line combination of HPLC with spectroscopic techniques [e.g., mass spectrometry, Fourier transform infrared (FT/IR), nuclear magnetic resonance], their application has not become routine in most biochemical and biomedical laboratories. 

The apparatus used for IR microscopy is a Fourier-transform infrared (FTIR) spectrometer coupled on-line with an optical microscope. The microscope serves to observe the sample in white light at significant magnification for the purpose of determining its morphology, as well as to select the area for analysis. The spectrometer, on the other hand, enables study of the sample by transmission or reflection measurement for the purpose of determining the chemical composition. It also provides information about the microstructure and optical properties (orientation) of the sample. It is possible to apply polarised light both in the observation of the sample and in spectrometric measurements. 

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