CHEMOMETRIC ANALYSIS OF GAS-CHROMATOGRAPHIC DATA OF OILS FROM EUCALYPTUS SPECIES

Gas chromatograms (GCs) of oil extracted from Eucalyptus species have been compared using principal components analysis (PCA), linear discri minant analysis (LDA), and the Tanimoto distance in which the number o f similar peaks between two species are determined. Two systems were s tudied, a number of examples of E. camaldulensis Dehnh. (River Red Gum ) and clones of that species, and samples from two trees E. woodwardii Maiden and E. torquata Luehm. and a number of their hybrids (E. torwo odii).The PCA revealed natural groupings of E. camaldulensis clones an d showed, via loading plots, that eight intensities of the 180 times s tudied were sufficient to explain most of the variance and characteris e each tree. The chemical species were identified by GC-mass spectrome try as alpha-pinene, 1,8-cineole, p-cymene, terpinen-4-ol/aromadendren e, cryptone, borneol, spathulenol, and torquatone. Each hybrid (E. tor wood) of the trees E. woodwardii and E. torquata has a distribution of oils that lies between those of the parents. LDA was able to define t wo distinct groups and performed better than the Tanimoto distance in classifying the trees.