Infrared spectrophotometry attenuated total reflectance

Products were characterized by Fourier transform infrared spectrophotometry-attenuated total reflectance (FTIR-ATR), ultraviolet visible (UV-Vis) spectrophotometry, scanning electron microscopy (SEM), and broadband dielectric/impedance spectroscopy (BDS). New absorption bands were observed corresponding to the conjugated pol5mieric units by FTIR-ATR and UV-Vis spectrophotometric analysis. The influence of concentration of PEDOT-PSS and PEDOT on the composite electrospun nanofibers was studied by EIS. Morphologies of electrospun nanofibers were also investigated by SEM. 

The chemical polymerization of Py by CAN in PU solutions leads to the formation of PU/PPy composites. The composites were characterized by Fourier transform infrared spectrophotometry-attenuated total reflectance (FTIR-ATR], dynamic mechanical analysis (DMA], thermal gravimetric analysis (TGA], differential scanning calorimetry (DSC], X-ray photoelectron spectroscopy (XPS], and SEM measurements. The absorbances of the disordered H-bonded urethane carbonyl decrease with increasing Py concentration. The fraction of the hydrogen-bonded carbonyls is increased and the melting point increases with the increase of PPy content. These indicate the incorporation of PPy into PU may cause the complex due to the intermolecular interaction between the PPy and PU. SEM images of composite nanofibers show good distribution of the second component and the composite solution is proper to form conductive composite nanofibers. 

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. 

Infrared spectroscopy underwent tremendous advances after the second world war and after 1950 with improvements in instrumentation and electronics, which put the technique at the center of chemical research and later in the 80 s in the biosciences in general with new sample handling techniques, the attenuated total reflection method (ATR) and of course the interferometer [13]. The Fourier TransformIR spectrophotometry is now widely used in both research and industry as a routine method and as a reliable technique for quality control. 

While infrared spectrophotometry is most useful for the qualitative analysis of surfactants, various quantitative methods have been developed for well-characterized systems. For example, an attenuated total reflectance cell with a ZnSe crystal is useful for direct analysis of aqueous anionic surfactant solutions by FTIR, while avoiding the deleterious effects of water on the usual transmission cells. In this case, the sulfonate absorbance at 1175 cm" , or the sulfate absorbance at 1206-1215 cm , is used for quantification (10,26). In another application, the weak absorption bands in the 1429-1333 cm" region are used to measure the relative amounts of linear and branched chain alkylbenzene sulfonates extracted from environmental waters (27). This is the one advantage of the infrared technique over those that have supplanted it for wastewater analysis its ability to differentiate the straight and branched chain compounds (28). No procedure will be given here, since the cleanup prior to IR analysis can be handled adequately by the method for LAS analysis by desulfona-tion/gas chromatography, described in Chapter 8. 

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