Infrared techniques FTIR, DRIFTS

The introduction of Fourier Transform Infrared Spectroscopy (FTIR) brought along a number of typical solid sample techniques. DRIFTS (Diffuse Reflectance Fourier Transform Infrared Spectroscopy) is probably most commonly known. Another technique, developed specifically for measuring solid, opaque samples is PAS (Photo Acoustic Spectroscopy). This accessory is less known, probably due to its high cost and its rather difficult modus operandi. 

Identification of the specific species of the adsorbed oxyanion as well as mode of bonding to the oxide surface is often possible using a combination of Fourier Transform Infrared (FTIR) spectroscopy, electrophoretic mobility (EM) and sorption-proton balance data. This information is required for selection of realistic surface species when using surface complexation models and prediction of oxyanion transport. Earlier, limited IR research on surface speciation was conducted under dry conditions, thus results may not correspond to those for natural systems where surface species may be hydrated. In this study we review adsorbed phosphate, carbonate, borate, selenate, selenite, and molybdate species on aluminum and iron oxides using FTIR spectroscopy in both Attenuated Total Reflectance (ATR) and Diffuse Reflectance Infrared Fourier Transform (DRIFT) modes. We present new FTIR, EM, and titration information on adsorbed arsenate and arsenite. Using these techniques we... 

The primary components and the chemical structure of the raw peat and the solid product were further analyzed by Fourier transform infrared spectroscopy (FTIR) 0ASCO 670 Plus) using the Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) technique and the JASCO IR Mentor Pro 6.5 software for spectral analysis. The cross polarization/magic angle spinning (CP/MAS) NMR spectrum of raw peat and the solid... 

Infrared spectroscopy IR and Fourier transform infrared (FTIR) spectra of humic substances show bands at 3400 cm (H bonding OFI), 2990 cm (aliphatic C-FI), 1725 cm(C = 0 of CO2H, C = 0 of ketone), 1630 cm (aromatic C = C, C = 0 of carbonyl, COO or quinone), 1450 cm (aliphatic C-H), 1400 cm - (COO ) and 1200 cm (C-O or OH of CO2H). The bands are usually broad due to overlapping of individual absorbances. While IR and FTIR provide worthwhile information about functional groups, they reveal little about the chemical structure of humic substances. FTIR and diffuse reflectance infrared Fourier transform (DRIFT) are the techniques most widely used. 

Fourier transform infrared spectroscopy (FTIR) is a useful way to confirm the presence of a desired functional transformation in a solid phase reaction. A high throughput diffuse reflectance infrared FT (DRIFT) technique allows spectra of beads to be collected without the need for KBr pelleting [9] and is reported to yield better data in the OH spectral region [10]. But a similar improvement in quality of spectra for... 

One of the major sample-handling problems in FTIR analysis of carbonaceous materials is that many of them are effective blackbody absorbers and thus are too opaque for direct transmission analysis in the midinfrared spectral region. Addition of KBr intensifies the signal to obtain transmission infrared spectra. It is time consuming, and grinding conditions and moisture are known to affect the spectrum of the sample [238]. Alternative techniques such as specular reflectance, diffuse reflectance (DRIFT), photoacustic spectroscopy (FTIR-PAS), and total... 

IR spectroscopy is one of the few analytical techniques that can be used for the characterization of solid, liquid, and gas samples. The choice of sampling technique depends upon the goal of the analysis, qualitative identification or quantitative measurement of specific analytes, upon the sample size available, and upon sample composition. Water content of the sample is a major concern, since the most common IR-transparent materials are soluble in water. Samples in different phases must be treated differently. Sampling techniques are available for transmission (absorption) measurements and, since the advent of FTIR, for several types of reflectance (reflection) measurements. The common reflectance measurements are attenuated total reflectance (ATR), diffuse reflectance or diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and specular reflectance. The term reflection may be used in place of reflectance and may be more accurate specular reflection is actually what occurs in that measurement, for example. However, the term reflectance is widely used in the literature and will be used here. 

Lignocellulosic material can also be analyzed by IR spectrometry. This analytical method was used for characterization of modified lignin and cellulose in various ways <>. Quantification by infrared spectrometry has been reported, for example, in analysis of the three basic constituents in sweet gum and white oak chips pretreated at temperatures ranging from 140 to 280 C. > using the diffuse reflectance FTIR spectrometry (DRIFT). The technique is simple and applicable to powdered solids and dark samples and... 

Spectroscopic data of CO2 metal complexes have been obtained and an attempt has been made to use them as an auxiliary technique for structure work-out in case XRD characterization of metal complexes was not available. Two spectroscopic techniques have mostly been used to this end, namely Infrared (IR, or FTIR, or DRIFT) and C-Nuclear Magnetic Resonance ( C-NMR), the former being most informative. Theoretical calculations have also been coupled with spectroscopic studies to get a better insight into the structural properties of the CO2 complexes. Good quality information can be gathered by carrying out a detailed analysis of multiple data, although individual pieces of information may be quite deceptive. 

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