Scanning compounded pellet

Characterization thus involves analytical electron microscopy, ordinary microprobe analysis or other techniques for localizing elements or chemical compounds (Scanning Auger Spectroscopy, Raman Microprobe, Laser Microprobe Mass Spectrometry). It also requires, in most cases, some physical separation of the catalyst for separate analysis (e.g., near surface parts and center of pellets, by peeling or progressive abrasion pellets present at various heights in the catalyst bed, etc.). 

Kinetic processes can be monitored by a technique known as time-resolved spectroscopy which involves FTIR. This method has been applied to analysis of complex materials such as polymer film stretching which can be carried out in milliseconds and chemical transformations involving, for example, coal pyrolysis it also permits on line analysis of products subject to chromatographic separation methods such as GC and LC. During the past five years GC-IR and GC-FTIR involved separating of mixtures and analysis of the individual compounds by IR spectroscopy. The sensitivity limitation of IR detectors with respect to GC and the time difference between the elution of a GC peak (measured in seconds) and the time scan were two of the problems encountered. GC-FTIR allows an IR spectrum taken from a 5-/u,g GC peak of isobutylmethacrylate by repeatedly scanning with spectral accumulation and enhancement (Fig. 8). FTIR measurements may be carried out by one of the following techniques (a) KBr pellets, (b) photoacoustic, and (c) diffuse reflectance methods. 

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