Chemical characterisation of the different types of volatile oil constituents by various solute retention ratios with the use of conventional and novel commercial gas chromatographic stationary phases

Retention ratios of an unknown solute peak from a volatile oil can help to identify its chemical type. Relative retentions on conventional stationary phases can be used to calculate a polar/non-polar ratio which may suggest i t is an aromatic solute or a sesquiterpene hydrocarbon. With dipentyl (DA) cyclodextrin phases, gamma -DA/alpha -DA ratios can indicate a bicyclic or monocyclic monoterpenoid. Temperature change on ct-DA can pick out a non-al coholic saturated cyclic monoterpenoid, using 150/125 degreesC. Twenty rete ntion ratios are reviewed involving various phases, including other modifie d cyclodextrins, liquid crystals, "Chirasil-Val" and crown ethers. Applicat ions to six volatile oils are made using a variety of phases. (C) 2001 Else vier Science B.V. All rights reserved.