Solid Phase Microextraction of Volatile Constituents from Individual Fresh Eucalyptus Leaves of Three Species

Abstract

Methyl polysiloxane solid-phase microextraction fibres were used for ten minutes to adsorb volatile constituents from headspace above all or part of a single cut up fresh eucalyptus leaf kept warm at 37 °C. The fibres were desorbed at 200 °C for programmed gas chromatography (40–187 °C) on a methyl polysiloxane capillary. Substances were identified by mass spectra and/or authentic sample retention. Results do not correspond to published values for steam distilled oils, being richer in sesquiterpenes, of which three are common to three different species; and also in esters in two species. Five Eucalyptus citriodora leaves from the same tree over different months gave very similar analyses to a fibre in 10min of 72.9–80.5 % citronellal, 3.5–5.4 % citronellol, 1.0–3.8 % citronellyl acetate, 9.2–11.8 % caryophyllene and 1.4–1.7 % bicyclogermacrene. Six E.nicholii leaves yielded 67.2–73.7 % cineole and 4.6–9.7 % limonene along with 10.5–16.5 % sesquiterpenes, mostly hydrocarbons, particularly bicyclogermacrene. E.globulus leaves gave only 54.0–61.3 % cineole, with 19.5–24.3 % α-pinene, 6.7–9.1 % limonene and 2.1–5.4 % α-terpinyl acetate; along with 3.6–7.7 % sesquiterpenes, particularly aromadendrene, but no bicyclogermacrene.

References

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