Control limit using discriminant analysis

In contrast to Raman and IR spectroscopy, only few chemical functionalities (CH, OH, and NH) have a signature in the NIR spectra. Thus, the use of NIR spectra as stmctural interpretation tool is strongly limited. For raw material control or discrimination purposes, however, such as the sorting of polymer waste into a selected numher of commodities (e.g., polyethylene, polypropylene, polystyrene, poly(ethylene ter-ephthalate) (PET), and poly(vinyl chloride) (Figure 51), qualitative chemometric evaluation techniques (such as principal component analysis (PCA)) can he applied. ... 

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