Pyrolysis gas chromatography/mass spectrometry used to simultaneously determine essential oil and phenolic compounds in the monks' pepper Vitex agnus-castus L.

Pyrolysis/gas chromatography/mass spectrometry (PY/GC/MS) was used as a microtechnique for the simultaneous analysis of various classes of compounds in leaves and berries of Vitex agnus-castus L. (Verbenaceae) plants growing wild in Calabria. Terpene and sesquiterpene hydrocarbons from the essential-oil fraction, simple phenolics, tentatively ascribed to moieties of flavonoids and glucosides, and free and esterified fatty acids were determined. Aliquots in the milligram range of plant material were assayed as such with no extraction or use of different analytical techniques for the different chemical classes under investigation. White the terpene and sesquiterpene yields remained practically constant over the entire range of pyrolysis temperatures examined, i.e. 200–900 °C, phenolics appeared at a pyrolysis temperature of 300 °C and reached a maximum at 700–900 °C. Pyrolysis in the presence of tetramethylammonium hydroxide was carried out in order to perform the so-called thermally assisted hydrolysis methylation/gas chromatography/mass spectrometry (THM/GC/MS) and analyse more polar compounds, such as fatty acids, as their methylated derivatives.