Quantitative Aspects of Flavour Analysis by Equilibrium and Dynamic Head-Space Gas Chromatography with Capillary Columns

Abstract

Equilibrium (E-HSGC) and dynamic (D-HSGC) headspace sampling procedures with capillary columns are compared. Split injection is widely used in headspace gas chromatography (HSGC) since a homogeneous gas mixture is injected and non linear split behaviour is unknown here. Splitless injection is recommended if headspace sampling is combined with cold trapping in order not to disturb the equilibrium, since a large sample is withdrawn over a longer period. In this case the well established methods for quantitave analyses with E-HSGC can be applied. These methods, including sample identification by pattern recognition, calibration by the technique of standard addition and the procedure of multiple headspace extraction (MHE) are discussed. Problems with D-HSGC techniques, particularly concerning an exhaustive stripping of all the volatile constituents from the sample without loss of the highly volatile ones by breakthrough in the adsorption tube are discussed also. In cases of mixtures with a wide range of volatilities, where the sample transfer can hardly be quantitative, the application of the MHE principle is suggested as a possible solution.