Fourier transform infrared high-temperature applications

NMR) [24], and Fourier transform-infrared (FT-IR) spectroscopy [25] are commonly applied methods. Analysis using mass spectrometric (MS) techniques has been achieved with gas chromatography-mass spectrometry (GC-MS), with chemical ionisation (Cl) often more informative than conventional electron impact (El) ionisation [26]. For the qualitative and quantitative characterisation of silicone polyether copolymers in particular, SEC, NMR, and FT-IR have also been demonstrated as useful and informative methods [22] and the application of high-temperature GC and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) is also described [5]. 

An interface between gel permeation chromatography (GPC) and Fourier transform infrared (FTIR) spectrometry has been developed. With this system it is possible to collect solvent free polymer deposition and to measure their infrared spectra as a function of molecular weight. The mobile phase from the GPC effluent is converted into an aerosol and removed using a pneumatic nozzle. The sample is collected on a Ge disc that rotates below the nozzle. After the sample is collected, the disc is transferred to an FTIR spectrometer where the infrared spectrum of the sample is collected. Normal GPC sample concentrations (0.1-0.25 wtJvol%) give sufficient sample for useable FTIR signals. All normal GPC solvents can be effectively removed, and the interface works with both low temperature and high temperature GPC applications. 

This paper presents examples of the application of diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy to the study of acid site chemistry and catalysis by product-selective molecular sieve materials. The most attractive features of the DRIFT method are that (i) uncompacted, high-surface-area powders can be studied in controlled chemical environments and over a wide range of temperatures (ii) reactants can be passed through a bed of the powdered sample and infrared spectra recorded simultaneously at temperatures in excess of 500 C with high species detection sensitivity and (iii) the sample can be repeatedly regenerated and exposed to reactants without being removed from the diffuse reflectance (DR) cell assembly. 

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