Fourier transform infrared analysis experimental methods

Even though these approaches are powerful methods for determining functional sites on proteins, they are limited if not coupled with some form of structural determination. As Figure 2 illustrates, molecular biology and synthetic peptide/antibody approaches are not only interdependent, they are tied in with structural determination. Structural determination methods can take many forms, from the classic x-ray crystallography and NMR for three-dimensional determination, to two-dimensional methods such as circular dichroism and Fourier Transformed Infrared Spectroscopy, to predictive methods and modeling. A structural analysis is crucial to the interpretation of experimental results obtained from mutational and synthetic peptide/antibody techniques. 

Surface analytical techniques. A variety of spectroscopic methods have been used to characterize the nature of adsorbed species at the solid-water interface in natural and experimental systems (Brown et al, 1999). Surface spectroscopy techniques such as extended X-ray absorption fine structure spectroscopy (EXAFS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) have been used to characterize complexes of fission products, thorium, uranium, plutonium, and uranium sorbed onto silicates, goethite, clays, and microbes (Chisholm-Brause et al, 1992, 1994 Dent et al, 1992 Combes et al, 1992 Bargar et al, 2000 Brown and Sturchio, 2002). A recent overview of the theory and applications of synchrotron radiation to the analysis of the surfaces of soils, amorphous materials, rocks, and organic matter in low-temperature geochemistry and environmental science can be found in Fenter et al (2002). 

Many experimental methods sueh as fluoreseenee, reflection Fourier transform infrared, NMR, quartz resonators, and acoustic wave admittance analysis, are used to study diffusion of solvents. " Special models have been developed to study process kinetics based on experimental data. 

Any technique for gas analysis can be applied to EGA. The most frequently used methods are mass spectroscopy (MS) and Fourier transform infrared spectroscopy (FTIR). Many instrument manufacturers provide the ability to interface their TGAs with MS or FTIR (see Section 3.7, on instrumentation). Temporal resolution between the TGA and the MS or FTIR detector is an important feature, for example, in distinguishing absorbed water from water as a reaction product and in assigning a decomposition product to a specific mass loss. Each method has its experimental requirements, limitations, and advantages. Mass spectroscopy is a very sensitive technique that identifies volatile species by their mass-to-charge ratio, referred to as m/z. The evolution of the sum of all mJz species can be plotted and compared with the derivative TGA plot to ensure temporal resolution between the TGA and the mass spectrometer. The evolution of a specific mJz, associated with species such as water or formaldehyde, can show the distinct evolution of these compounds. The most common ionization is by 70eV electron impact (El), which operates... 

There are also more recent developments of other dual physio-chemical experimental methods. For example Durand et al (2006) presented a laboratory-made system that allows the coupling of dielectric analysis and Fourier-transform near-infrared spectroscopy (FT-NIR) to follow the cure of polyepoxy reactive systems. Complementary data are provided by the simultaneous dielectric analysis (the vitrification phenomenon) and near-infrared spectroscopic analysis (the extent of the reaction). 

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