Abstract
It was found possible to distinguish between four kinds of crude drugs containing anethole, fennel, sweet fennel, anise, and star anise from their essential oils, using infrared absorption spectra. For this purpose, anethole content and difference in coexisting components were spectrally analyzed. For the determination of anethole, characteristic absorption of a propenyl group at 961cm-1 was used. In fennel, characteristic absorption of fenchone at 1743cm-1 was used. For discrimination of anise and star anise oils, differential method was used and a good result was obtained by the use of absorption at 1371cm-1, appearing stronger in star anise oil. This absorption was considered to be due to the concerted effect of isopropyl group in cineol, terpineol, and phellandrene.
