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12 M. Sajewicz et al.

From this comparison it is apparent that for three of the five sagę species investigated head-space extraction at 70°C yielded the largest numbers of volatile compounds (fourteen for S. lauandulifolia and eleven for S. hians and S. nemorosa). Head-space extraction at 70°C was also the most quantitatively efficient. Head-space extraction at 80°C was somewhat less efficient (yield-ing thirteen volatile compounds for S. lauandulifolia, five for S. nemorosa, and four for S. hians). Head-space extraction at 80°C also resulted in worse peak resolution than that at 70°C, which negatively affected both Identification and quantitative comparison of the compounds. Vapour distillation in the Deryng apparatus yielded thirteen identified compounds for S. staminea, eleven for S. lauandulifolia, ten for S. tńloba, seven for S. hians, and only two for S. nemorosa. Accelerated solvent extraction (ASE) with petroleum ether as extractant proved the least efficient, yielding six volatile compounds for S. lauandulifolia and S. tńloba, two for S. staminea, one for S. nemorosa, and nonę for S. hians. These results led to three observations:

•    A temperaturę of 70°C was usually better suited to head space ex-traction than 80°C. Elevation of the temperaturę resulted in deterio-ration of the separation of the compounds, which negatively affected identification and quantitative comparison.

•    Ali the extraction techniques except ASE with petroleum ether en-abled efficient isolation of most of the volatile compounds from S. lauandulifolia.

•    There is no doubt that ASE with petroleum ether can be applied only to plant materiał containing large amounts of volatile compounds.

Visual inspection of the chromatograms shown in Figs 1-5 also confirmed these observations.

Seasonal differences between the qualitative and quantitative composi-tion of the volarile compounds from the five different sagę species are apparent from the results given in Tables ll-Vl and Figs 1-5. The compounds identified in the volatile fractions obtained from the five species collected in 2007 and 2008 isolated from the crude plant materiał by means of the four different extraction techniques are listed in Tables II-VI, which also contain the percentage contributions of the respective peak heights for the identified volatile compounds to the sum of the peak heights for all the volatile compounds recorded. In these tables emboldening is used to indicate chemotaxonomic markers and chemotaxonomic advice compounds estab-lished for four of the sagę species investigated in previous work [14].