Comparative study of the aromas of Hypericum L-species from Portugal using olfactroscopy

The analysis of the aroma of Portuguese Hypericum L. species (Guttiferae) was performed using a sensor array detection device equipped with a multi-element array of 32 chemical sensors. Studies included the investigation of eight species (plant material and essential oils), sample preparation (drying, including lyophilization) and conservation procedures. A multivariate analysis (PCA and Sammon Mapping) of the data was carried out in order to summarize the sensor responses. Preliminary results suggest that the main differences occurring among groups of samples are due to sample preparation and to taxonomical identity. Although less powerful, results obtained by this method seem to be consistent with those of headspace and CC-MS. The importance of prior tests using this method of establishing gross patterns is emphasized. Classification of plant samples using sensor array detection prior to carrying out finer analytical methods (e.g. GC and GC-MS) was therefore found to be of advantage. Copyright (C) 1999 John Wiley & Sons, Ltd.