Heuristic evolving latent projections HELP

The method also provides what is called a data-scope, which zooms in on a particular part of the data set. The functioning of the data-scope is illustrated with a simulated three-component system given in Figs. 34.33a and b. The scores plot (Fig. 34.33c) obtained by a global PCA in wavelength space shows the usual line structures. In this case the data-scope technique is applied to evaluate the purity of the up-slope and down-slope elution zones of the peak. Therefore, data-scope performs a local PCA on the up-slope and down-slope regions of the data. 

In Fig. 34.34 the first three local PCs with the associated eigenvalues are given for four retention time regions (a) a zero component region (Fig. 34.34a), (b) selective chromatographic regions at the up-slope side (Fig. 34.34b), (c) and at the 

Local rank analysis of suspected selective regions in a LC-DAD data set (see Fig. 34.34) 

PC Zero-compound region Suspected selective region (up-slope) Suspected selective region (down-slope) 

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Other Techniques Subwindow Factor Analysis (SFA) and Heuristic Evolving Latent Projections (HELP)... 

Other recently developed chemometric approaches include Heuristic evolving latent projections (HELP) [162] which is primarily used for the analysis of qualitative and quantitative data from 2-dimensional data (e.g. HPLC DAD) used for complex mixtures, and HELP lessens the demand on developing complicated separation methods mixed level orthogonal array design (ML-OAD) has been used to optimise the parameters involved in HPLC detection [163]. The LC methods for determining the purity of tetracycline HCl and resolution... 

GC—gas chromatography HCA—hierarchical cluster analysis HELP—heuristic evolving latent projections HHM—horse heart myoglobin HPLC—high performance liquid chromatography HPLC-DAD—high performance liquid chromatography-diode array detector... 

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