Fourier transform infrared powders

The ability of the new precursors to decompose thermally to yield singlephase CIS was investigated by powder XRD analysis and EDS on the nonvolatile solids from the TGA experiments of selected compounds. Furthermore, using TGA-evolved gas analysis (EGA), the volatile components from the degradation of the SSPs could be analyzed via real-time fourier transform infrared (FTIR) and mass spectrometry (MS), thus providing information for the decomposition mechanism.3 The real-time FTIR spectrum for 7 and 8 shows absorptions at approximately 3000,1460,1390,1300, and 1250 cm-1 (see Fig. 6.7). 

Non-ionic surfactants of a commercial washing powder were separated by supercritical fluid chromatography (SFC) and determined by APCI-MS. The constituents were first extracted by supercritical fluid extraction (SFE) using C02 with or without methanol as a modifier. Variations of the conditions resulted in a selective extraction of the analytes, which could be determined without further purification. Six groups of surfactants were observed, four of which are alkyl-polyethoxylates. The presence of APEO could be excluded by identification recording SFC-FTIR (Fourier transform infrared) spectra [31]. 

Abstract—This study extends previous work on silanized kaolin clays to other substrates, such as aluminum hydroxide. It will also show that high precision quantitative Fourier Transform Infrared Spectroscopy (FT-IR) diffuse reflectance measurements can be performed on this vinyl silanized substrate and predict that other silanized finely divided powders can be analyzed using these techniques. 

The solid-state properties like crystallinity, polymorphism (crystal structure), shape (morphology), and particle size of drugs are important in the stability, dissolution, and processibility of drugs. Some commonly used methods in solid-state studies include microscopy, hot stage microscopy with polarized light, x-ray powder diffraction (XRPD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared FTIR/Raman, and solid-state NMR. 

Several methods have been used to characterize complexes in solid-state. Among the most commonly used methods are differential scanning calorimetry (DSC), x-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and x-ray crystallography. In recent years, the NMR method has showed many utilities (Ficarra et al., 2002 Rajendrakumaret al. 2005 Lantz et al., 2006). 

The physical state of the drug incorporated in a powder drug delivery system (e.g., degree of crystallinity and possible interactions with the polymer) is assessed by differential scanning calorimetry (DSC) or Fourier transform infrared (FTIR) spectroscopy. These observations can clarify the results of other parameter investigations, especially the results of in vitro drug release studies. 

Two other types are still in usage for special purposes. Hydraulically operated machines are used to produce tablets, for example, for Fourier transform infrared (FTIR) spectroscopy. In this case the upper punch moves hydraulically onto the powder bed and the tablet is formed in the die. The other possibility is an eccentric tableting machine, which will be described in the following. 

Conversion of the as-deposited film into the crystalline state has been carried out by a variety of methods. The most typical approach is a two-step heat treatment process involving separate low-temperature pyrolysis ( 300 to 350°C) and high-temperature ( 550 to 750°C) crystallization anneals. The times and temperatures utilized depend upon precursor chemistry, film composition, and layer thickness. At the laboratory scale, the pyrolysis step is most often carried out by simply placing the film on a hot plate that has been preset to the desired temperature. Nearly always, pyrolysis conditions are chosen based on the thermal decomposition behavior of powders derived from the same solution chemistry. Thermal gravimetric analysis (TGA) is normally employed for these studies, and while this approach seems less than ideal, it has proved reasonably effective. A few investigators have studied organic pyrolysis in thin films by Fourier transform infrared spectroscopy (FTIR) using reflectance techniques. - This approach allows for an in situ determination of film pyrolysis behavior. 

Due to their large surface area for adsorption, porous materials are useful excipients for solid dispersions. For example, 2-naphthoic acid (2-NPA) solid dispersion with porous crystalline cellulose (PCC) has been successfully prepared by heat treatment of 2-NPA and PCC mixture. " PCC is derived from MCC, but with a larger surface area. Different from 2-NPA mixed with PCC, 2-NPA mixed with MCC still maintained a crystalline form under the same mixing and heating conditions. Various experimental data such as X-ray powder diffraction, Fourier transform infrared (FT-IR) spectroscopy, and solid-state fluorescence measurements suggest that 2-NPA is adsorbed onto the surface of PCC and becomes molecularly dispersed into the system. 

Stahlmann, S. Kovar, K.-A. Analysis of impurities by high performance thin layer chromatography with fourier transform infrared spectroscopy and UV absorbance detection in situ measurement chlordiazepoxide in bulk powder and its tablets. J. Chromatogr. A 1998, 813, 145-152. 

The most useful spectral methods for the characterization of water in solids are Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and powder X-ray diffraction (XRD). A thorough treatment of these methods is not given here instead the example of ampicillin presented by Brittan, et sdP is summarized. 

Titanium sulfate supported on zirconia catalysts were prepared by drying of powdered Zr(OH)4 with titanium sulfate aqueous solution followed by calcining in air at high temperature. The characterization of prepared catalysts was performed using Fourier transform infrared (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and by the measurement of surface area. The addition of titanium sulfate to zirconia shifted the phase transition of ZrOa from amorphous to tetragonal to higher temperature because of the interaction between titanium sulfate and zirconia. The catalytic activities for both reactions, 2-propanol dehydration and cumene dealkylation were correlated with the acidity of catalysts measured by ammonia chemisorption method. 

A combination of techniques, such as powder X-ray diffraction (XRD) [56, 58], thermogravimetric analysis (TGA) [57], differential thermal analysis (DTA) [57], X-ray photoelectron spectroscopy (XPS) [56, 58], scanning electron microscopy (SEM) [26, 57], Fourier transform infrared (FT-IR) spectroscopy [57, 58] and BET N2 adsorption measurements [67], was used for structural characterization of the enzyme-clay conjugates. 

During the past decade, the main advances in the spectroscopic characterization of silica powders have come from 29Si NMR, Raman diffusion, and Fourier transform infrared (FTTR) studies. NMR studies have given two types of results. First, single and geminal silanols have been quantitatively differentiated as a function of dehydroxylation by thermal treatment and subsequent rehydroxylation by liquid water (7). The fraction of geminal silanols... 

J.G. Highfield, P. Bowen, Diffuse-Reflectance Fourier Transform Infrared Spectroscopic Studies of the Stability of Aluminum Nitride powder in an Aqueous Environment, Anal. Chem., 61 (1989) 2399. 

Highfield, J. G., and Bowen, P., Diffuse-reflectance Fourier transform infrared spectroscopic studies of the stability of aluminum nitride powder in an aqueous environment, Anal. Chem., 61, 2399 (1989). 

Mesoporous alumina samples have been synthesized using poly(ethylene oxide)-based nonionic surfactants. The effect that the addition of n-alkylamines to the synthesis gel has on the texture and thermal stability of mesoporous aluminas is studied. Textural and structural characterization using nitrogen adsorption, powder X-ray diffraction, a1 nuclear magnetic resonance and Fourier Transform infrared spectroscopy, as well as catalytic n-hexane hydroisomerization tests are performed. 

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