Graphical Representation of Scores and Loadings

Hence the PC plot suggests that die region between 6 and 10 s (approximately) is one of co-elution. The reason why diis method works is that die spectrum over the chromatogram changes widi elution time. During co-elution the spectral appearance changes most, and PCA uses this information. 

Scores of PC2 (vertical axis) versus PCI (horizontal axis) for case study 1 

Scores plots can be used to answer many different questions about the relationship between objects and more examples are given in the problems at the end of this chapter. 

Scores of the first two PCs of case study 1 versus sample number 

Further interpretation is possible, but it can easily be seen that the loadings plots provide detailed information about which wavelengths are most associated with which compound. For complex multicomponent clusters or spectral of mixtures, this information can be very valuable, especially if the pure components are not available. 

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