Comparison of chemometric methods for classification of fungal extracts based on rapid fluorescence spectroscopy

Rapid fluorescence landscapes were recorded on 137 extracts of five species of Penicillium and seven extracts of pure growth medium. The ability of the following methods to show six classes was investigated: principal component analysis; parallel factor analysis; discriminant partial least squares regression and N-PLS with dummy Y matrix: correspondence analysis; soft independent modelling of class analogy; principal co-ordinate analysis; non-metric scaling; and cluster analysis on similarity matrices with different similarity measures. Cluster analysis was also performed on sets of score vectors. The best measure of similarity was the correlation coefficient. None of the methods was entirely successful, because two species had some highly fluorescent compounds in common. All the tested chemometric methods obtained a level of correct classification, which normally requires mycological experts, for three species. All methods were able to capture most of the same information, but cluster analysis gave the dearest result for both classes and outliers and was the easiest method to perform and evaluate. Copyright (C) 2000 John Wiley & Sons, Ltd.