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 (K f,) 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 calculate d and experimentally measured K-fg values for the same group of 13 compound s, including monoterpene hydrocarbons, alcohols and ethers. A good agreemen t between the two values (RSD < 11%) was-found for most compounds, even whe n a BPX-5 GC column was used for the determination of the LTPRI values. The derived model was then applied to the prediction of K-fg values for 37 oth er terpenoids found in aromatic plants. The similarity between calculated a nd experimentally measured K-fg values was found to be acceptable, even whe n the model was extrapolated for compounds with LTPRIs as high as 1481. Som e of the predicted values were then applied to the quantitative determinati on of damage-induced changes in the headspace concentration above Salvia of ficinalis L. (common sage) leaves. The relationship established in this pap er enables the simple and accurate determination of terpenoids in the gas p hase, using polydimethylsiloxane-solid-phase microextraction (PDMS-SPME) at 25 degreesC. Copyright (C) 2001 John Wiley & Sons, Ltd.