Differentiation of ten pine species from central Portugal by monoterpene enantiomer-selective composition analysis using multidimensional gas chromatography

The composition of the volatile terpenes emitted by different trees has bee n successfully used as markers in a wide variety of studies such as chemota xonomy. In this work discrimination among ten pine species, P. pinea, P. pi naster, P. brutia, P. elliottii, P. halepensis, P. kesiya, P. rodiata, P. p atula, P. sylvestris, and P. taeda was achieved by analyzing the relative c omposition of their volatile emissions. The analysis was performed after si multaneous distillation extraction; 16 monoterpenes were identified. My mea ns of principal component analysis it was shown that discrimination among s pecies could be maximized by taking into account three monoterpenes only -a lpha -pinene, beta -pinene,and limonene. In a second stage of the work the extracts were submitted to enantiomer-selective multidimensional gas chroma tography (MDGC). The enantiomer ratio was determined after separation on a tailor-made 2,3-dimethyl-6-Cr-tert-butyldimethylsilyl-beta -cyclodextrin an alytical column. Application of principal component analysis to the samples enabled their comparative characterization.