Quantitative analysis of terpenoids in the gas phase using headspace solid-phase microextraction (HS-SPME)

A relationship between the fibre coating/gas phase partition coefficient (Kfg) of terpenoids and their linear temperature programmed retention index (LTPRI) was derived using a group of selected monoterpenoids (with LTPRI's ≤ 1124). The accuracy of this relationship was tested by comparing calculated and experimentally measured Kfg values for the same group of 13 compounds, including monoterpene hydrocarbons, alcohols and ethers. A good agreement between the two values (RSD ≤ 11%) was found for most compounds, even when a BPX‐5 GC column was used for the determination of the LTPRI values. The derived model was then applied to the prediction of Kfg values for 37 other terpenoids found in aromatic plants. The similarity between calculated and experimentally measured Kfg values was found to be acceptable, even when the model was extrapolated for compounds with LTPRIs as high as 1481. Some of the predicted values were then applied to the quantitative determination of damage‐induced changes in the headspace concentration above Salvia officinalis L. (common sage) leaves. The relationship established in this paper enables the simple and accurate determination of terpenoids in the gas phase, using polydimethylsiloxane–solid‐phase microextraction (PDMS–SPME) at 25 °C. Copyright © 2001 John Wiley & Sons, Ltd.