The Qualitative and Quantitative Determinations of Volatile Constituents in Some Herbal Medicines by Gas Chromatography

Many herbal medicines pertain characteristic odour which indicates the volatility of some compositions. Most of the volatiles constituents have low molecular weight, typically, monoterpenes, sesquiterpenes and phenylpropanes and their oxygenated derivatives (Harnone, 1998). Some herbs contain high content of volatile oils from which the oil themseleves are used as drugs, for example eucalyptus oil, eugenol etc., but some are very low. Volatile oils are some times called essential oils due to the believed that it is the essence of the herb. At present, qualitative or identification by gas chromatography (GC) is well established due to the availability of mass spectrometer (MS) detector. When constituents are identified, the interested components can be quantitatively determined by the flame ionization detector (FID).