Fourier-transform infrared transmittance FTIR

The hydrogen content Ch greatly influences structure and consequently electronic and optoelectronic properties. An accurate measurement of Ch can be made with several ion-beam-based methods see e.g. Arnold Bik et al. [54]. A much easier accessible method is Fourier-transform infrared transmittance (FTIR) spectroscopy. The absorption of IR radiation is different for different silicon-hydrogen bonding configurations. The observed absorption peaks have been indentified [55-57] (for an overview, see Luft and Tsuo [6]). The hydrogen content can be determined from the absorption peak at 630 cm , which includes... 

The chemical modification of the clay can be studied with the help of Fourier transform infrared spectroscopy (FTIR). In FTIR spectra of co-treated and mono-treated clays, the transmittance bands at 2922 cm and 2854 cm correspond to asymmetric and symmetric stretching vibration of methylene groups (Figure 9.5). Carbonyl stretching shows a band at 1715 cm. Both the mono-treated and co-treated montmorillonites have the absorbance bands of methylene, which is due to the successful tethering of octodecylammonium and aminoimdecanoic acid to the clay platelets [24]. 

A Fourier transform infrared spectrophotometer (FTIR, model-IR Prestige-21, Schimadzu Corporation, Japan) was used for the structural determination of functional groups and compounds. The FTIR spectra of modified and unmodified clay in the solid state using potassium bromide (KBr) as a reference material were recorded by diffuse reflectance spectroscopy (DRS technique). This technique consists of preparation of sample by mixing about 0.5 mg of powder sample with 50 mg of high-purity infrared-grade KBr powder (Aldrich). The KBr was previously oven dried to reduce the interference of water. The spectra were recorded in the wave number range of 4000—400 cm with a resolution of 4 cm and 20 scans were carried for each sample in transmittance mode. 

A Fourier transform infrared spectroscopy (FTIR) study was obtained by using Perkin-Elmer spectrometer 100, USA. Prior to this analysis, kenaf whiskers were mixed with KBr to prepare homogeneous suspensions and afterwards pressed into transparent pellets and analyzed in transmittance mode within the range of 4000-500 cm. In the case of thin nanocomposite film (Cellulose Acetate Butyrate [CAB] and kenaf whiskers) the analysis was done within the range of 4000-500 cm transmittance mode. 

Fourier transform infrared microscopy is the primary infrared technique for structural identification of materials at microquantities. The method is non-destructive and non-invasive. When using a proper transmittance sampling technique and a proper detector, the limit of detection can be as low as the picogram level. In the pharmaceutical industry, FTIR microscopy is used to analyze bulk drugs, excipients, and particulate contaminants. " Recent studies have shown that by coupling FTIR microscopy with GC, HPLC, SFC, or GPC systems, the detection limit of the method is substantially improved. ... 

Fourier transform infrared (FTIR) analysis works on the fact that chemical bonds and groups of chemical bonds vibrate at characteristic frequencies. During FTIR analysis, a modulated infrared (IR) beam is spotted on the specimen. The transmittance and reflectance of the infrared rays at different frequencies is then translated into an IR absorption plot consisting of reverse peaks, which after matching and identification provides information about the chemical bonding or molecular structure of materials, whether organic or inorganic. 

UV-Vis absorbance spectroscopy measurements were performed on a Spectra Max 190 plate reader (Molecular devices, Sunnyvale, USA) operated at a resolution of 1 nm. Fourier transform infrared (FTIR) analysis of the samples dried in KBr pellet was performed on a Nicolet Model 6700 spectrophotometer in a difiuse transmittance mode at 4 cm resolution. XRD of dried silver nanoparticle samples drop-coated on glass substrate was performed on a PANalytical X pert PRO X-ray diffractometer (Netherlands), operated at 40 kV and at a current of 40 mA. TEM measurements for the samples prepared on carbon-coated copper grids were performed on a HR-TEM (JEOL-Model 3010) operated at an accelerating voltage of 200 keV. 

Siuface functional groups of the membrane were characterized by Fourier transform infrared (FTIR, Varian 1000, Varian Inc., Palo Alto, CA) spectroscopy in attenuated total reflection (ATR) mode. Membrane surface samples were mounted on face of the crystal surface. Spectra were measured in transmittance mode over a wave length of 600-4000 cm at a resolution of 4 cm. ... 

An infrared spectrum is a plot of percent radiation absorbed versus the frequency of the incident radiation given in wavenumbers (cm ) or in wave length ( xm). A variation of this method, diffuse reflectance spectroscopy, is used for samples with poor transmittance, e.g. cubic hematite crystals. Increased resolution and sensitivity as well as more rapid collection of data is provided by Fourier-transform-IR (FTIR), which averages a large number of spectra. Another IR technique makes use of attenuated total reflectance FTIR (ATR-FTIR) often using a cylindrical internal reflectance cell (CIR) (e.g. Tejedor-Tejedor Anderson, 1986). ATR enables wet systems and adsorbing species to be studied in situ. 

Infrared spectra are represented in terms of a plot of percentage transmittance versus wavenumber (cm-1). In its most common form, infrared spectroscopy makes use of Fourier transformation, a procedure for interconverting frequency functions and time or distance functions. Fourier-transform IR (FTIR) spectroscopy allows the rapid scanning of spectra, with great sensitivity, coupled with... 

The method of diffuse transmittance (DT) is based on measurement of the radiation component 7dt (Fig. 1.22) that passes diffusely through an inhomogeneous layer. This method was first applied to the IR spectroscopic analysis of thin films on samples in powder form by Tolstoy in 1985 [116, 117], who obtained DT spectra of water adsorbed onto silica gel. When used in conjunction with a FTIR spectrometer, the method is called diffiise-transmittance infrared Fourier transform spectroscopy (DTIFTS). DTIFTS is the most recently developed IR spectroscopic methods for studying powder surfaces and has already found application in high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC) [118, 119]. Of increasing popularity are DTIFTS measurements of powders that use an IR microscope to collect radiation [112, 119] (Section 4.3). 

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