ANALYSIS OF PINUS SPP ESSENTIAL OILS BYENANTIOSELECTIVE COMPREHENSIVE TWO-DIMENSIONALGAS CHROMATOGRAPHY/TIME-OF-FLIGHT MASSSPECTROMETRY (GCXGC/TOFMS)

The enantiomers of chiral terpenes present in the volatile blends emitted by Pinus spp. should analytically be considered as individual components, due to their inherent potential role in insect-host plant relationships, and in the chemical discrimination of pine species. The separation of enantiomeric monoterpenes by GC × GC analysis was performed with a taylor made fused silica capillary column with 30 m × 0.25 mm I.D., coated with 0.25 15% heptakis (2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)- SE52 (2,3-DiMe) on the first dimension. The column was coupled to a polar column (Supelco-Wax) composing an original set of columns for GC × GC. In order to collect information and evaluate the set performance in GC × GC, a solution with a mixture of 43 standards was analysed before the Pinus samples. The chemical composition of the needles of P. pinea, P. pinaster, P. halepensis, P. nigra, P. brutia, P. patula, P. radiata, P. taeda, P. elliotti, P. kesiya and P. sylvestris was investigated. Steam distillation extraction (SDE) was used to collect the volatile fractions. The use of GC × GC resulted in enhanced separation efficiency and increased signal to noise ratio (sensitivity) of the analytes, maximizing mass spectra quality and improving compound detection and identification. The mass spectra obtained by GC × GC showed a better quality than those obtained by 1D-GC/TOFMS, providing higher match library factors with the NIST/Wiley searchable libraries, and thus a stronger identification of the compounds present in the samples than by one-dimensionalμm film ofβ-cyclodextrin in GC analysis. The enantio-GC × GC analysis performed for all the Pinus spp. under study achieved the detection of 422 different compounds.