Use of principal components analysis for displaying variation between pyrograms of micro-organisms

Principal components analysis is used to display variations between batches of pyrograms of micro-organisms represented by sets of peak heights. Although it is not usually suitable for discriminating genus or species groups, it provides a means of detecting aberrant analyses, unsuspected trends in the data and of assessing reproducibility. It can also provide information relating specific peaks or sets of peaks to clusters of samples.These uses of principal components analysis are not confined to pyrolysis—gas—liquid chromatography; the technique can be applied widely to quantitative chromatographic and mass spectrometric data.