ATR-FTIR attenuated total

ATR FTIR attenuated total reflectance Fourier CSEi small-scale fluctuations... 

ATR-FTIR attenuated total reflectance-Foiu-ier transform infrared spectroscopy G guanine... 

ATR-FTIR Attenuated total-reflection Fourier-transform infrared spectroscopy... 

ATR-FTIR Attenuated Total Reflection Fourier Transform Infrared Spectroscopy... 

ATR-FTIR Attenuated total reflectance-Fourier transform infrared... 

ATR-FTIR attenuated total reflectance-I ouiicr transform infrared spectroscopy BET Brunauer-Emmett-Teller surface area measurement CA chronoamperometry... 

Several reviewers of this chapter have stressed that the model proposed in Figure 18 is speculative. It is, in the sense that there are so many variables in a coating formulation that no mechanism will be universal (i.e., this mechanism is not being proposed for vinyl-acrylic HEC-stabilized latices). The carboxylate cation ion-dipole interaction with the oxygen atoms of the oxyethylene units is not speculative. Numerous publications other than the one ATR-FTIR (attenuated total reflectance-Fourier transform infrared)... 

ATR-FTIR (attenuated total reflection infrared) Olefin polymerization (ethene/1-hexene) [70] Polycondensation of diols and carbamic acid, equilibrium of isocianates with alcohols [71] Non-invasive, well suited for polycondensation/Poor fiber-optic transmission, not well suited for waterborne polymerization All polymerization techniques... 

ATR-FTIR Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy Infrared hght Detailed chemical information. Nonvacuum method. Specimens must be flat and capable of intimate contact with the necessary crystal. 

Fourier transform infrared (FTIR)-attenuated total reflection (ATR) spectra have been measured for LB films of stearic acid deposited on a germanium plate with... 

Important to quality control are the comparison and confirmation of drug substance identity, excipients, and packaging components. Techniques such as Fourier transform IR (FTIR), attenuated total reflectance (ATR), NIR, Raman spectroscopy are used with increased regularity. The detection of foreign metal contaminants is essential with inductively coupled plasma spectroscopy (ICP), atomic absorption (AA), and X-ray fluorescence. Also notable is the increased attention to analysis of chiral compounds, as in the synthesis of drug substances. Optical rotation, ORD, and CD are currently the preferred instruments for this practice. The analytical techniques commonly used in the preformulation study are discussed in the following. 

The polymer properties in thin films are then compared with the bulk as measured by FTIR attenuated total reflection spectroscopy (ATR). A modest refractive index of the internal reflection element (IRE made of ZnSe, n=2.43 at 2000 cm ) and an incident angle of 65° - still low but well above the critical angle of total reflection - are chosen for the p-polarized light in order to obtain an information depth of several microns. Hence, the ATR spectra provide the bulk properties of the polymer sample. 

The surface structure of melt-mixed blends of bisphenol A polycarbonate and PETP was investigated by FTIR attenuated total reflectance spectroscopy. Based on the peak intensity of the aromatic carbonate band for polycarbonate and the aliphatic ester band for PETP by using germanium and KRS-5 ATR crystals, the enrichment of the PETP component in the surface layer of the polycarbonate/PETP blend films was observed. 27 refs. 

In the case of linear spectroscopic methods such as FTIR, attenuated total internal reflection (ATR) has been used to enhance the sensitivity of these methods [38-40]. In a similar fashion, a total internal reflection geometry has been used here to enhance the otherwise weak sum-frequency (SF) response from the liquid/liquid interface. In addition to a strong resonant contribution from the C-H stretching vibrations within the molecules, the intensity is also dependent upon the Fresnel factors for the input fields, /i, and the outgoing SF, fsp, as shown in Eq. (1). When the incident beams are directed on the interface at their respective critical angles, an enhancement of several orders of magnitude in the SF response is achievable over that of an external reflection geometry [25,35,36,41-43]. 

FTIR-Attenuated Total Reflectance (FTIR-ATR) spectroscopy was used to analyze networking of the geopolymer structure. Ground samples were placed onto the ATR silicon crystal and clamped to obtain good contact. The IR spectra were recorded using an Nexus 670 FT-IR Thermo Nicolet spectrometer with DTGS detector and Smart 7 MIRacle ATR (Thermo Nicolet) adapter with Si plate.. 

Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy. Attenuated total redectance (atr) ftir spectroscopy is based on the principle of total internal redection (40). Methods based on internal redection in the uv and visible regions of the spectmm are also common in addition to those in the ir region. The implementation of internal redection in the ir region of the spectmm provides a means of obtaining ir spectra of surfaces or interfaces, thus providing moleculady-specific vibrational information. 

Attenuated total reflection, on which atr—ftir is based, occurs when the rarer medium is absorbing and is characterized by a complex refractive index (40). The absorbing characteristics of this medium allow coupling to the evanescent field such that this field is attenuated to an extent dependent on k. The critical angle in the case of attenuated total reflection loses its meaning, but internal reflection still occurs. Thus, if the internally reflected beam is monitored, its intensity will reflect the loss associated with the internal reflection process at the interface with an absorbing medium. 

Adsorption phenomena from solutions onto sohd surfaces have been one of the important subjects in colloid and surface chemistry. Sophisticated application of adsorption has been demonstrated recently in the formation of self-assembhng monolayers and multilayers on various substrates [4,7], However, only a limited number of researchers have been devoted to the study of adsorption in binary hquid systems. The adsorption isotherm and colloidal stabihty measmement have been the main tools for these studies. The molecular level of characterization is needed to elucidate the phenomenon. We have employed the combination of smface forces measmement and Fomier transform infrared spectroscopy in attenuated total reflection (FTIR-ATR) to study the preferential (selective) adsorption of alcohol (methanol, ethanol, and propanol) onto glass surfaces from their binary mixtures with cyclohexane. Om studies have demonstrated the cluster formation of alcohol adsorbed on the surfaces and the long-range attraction associated with such adsorption. We may call these clusters macroclusters, because the thickness of the adsorbed alcohol layer is about 15 mn, which is quite large compared to the size of the alcohol. The following describes the results for the ethanol-cycohexane mixtures [10],... 

FTIR instrumentation is mature. A typical routine mid-IR spectrometer has KBr optics, best resolution of around 1cm-1, and a room temperature DTGS detector. Noise levels below 0.1 % T peak-to-peak can be achieved in a few seconds. The sample compartment will accommodate a variety of sampling accessories such as those for ATR (attenuated total reflection) and diffuse reflection. At present, IR spectra can be obtained with fast and very fast FTIR interferometers with microscopes, in reflection and microreflection, in diffusion, at very low or very high temperatures, in dilute solutions, etc. Hyphenated IR techniques such as PyFTIR, TG-FTIR, GC-FTIR, HPLC-FTIR and SEC-FTIR (Chapter 7) can simplify many problems and streamline the selection process by doing multiple analyses with one sampling. Solvent absorbance limits flow-through IR spectroscopy cells so as to make them impractical for polymer analysis. Advanced FTIR... 

FTIR spectroscopy was conducted on the white residue using an attenuated total reflection (ATR) attachment [l].1 After the blister was opened, the ATR... 

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. 

Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), 24 111-114 Attenuation, 77 132-133 Attenuation length (AL), 24 87-89 Attrition, catalyst deactivation mechanism, 5 256t... 

The infrared technique has been described in numerous publications and recent reviews were published by Davies and Giangiacomo (2000), Ismail et al. (1997) and Wetzel (1998). Very few applications have been described for analysis of additives in food products. One interesting application is for controlling vitamin concentrations in vitamin premixes used for fortification of food products by attenuated total reflectance (ATR) accessory with Fourier transform infrared (FTIR) (Wojciechowski et al., 1998). Four vitamins were analysed - Bi (thiamin), B2 (riboflavin), B6 (vitamin B6 compounds) and Niacin (nicotinic acid) - in about 10 minutes. The partial least squares technique was used for calibration of the equipment. The precision of measurements was in the range 4-8%, similar to those obtained for the four vitamins by the reference HPLC method. 

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