| Abstract: | A procedure for direct gas chromatographic analysis of volatile constituents present in the headspace above wines has been developed. Samples of wine (100 ml) and its headspace were conditioned for specified times and temperatures so as to reach air-liquid equilibrium in a special large syringe (2000 ml) designed in our laboratory. The headspace volatiles were collected directly, freed from water and ethanol in a short trap packed with Porapak Q connected to the syringe. The vapour passed from the syringe to the precolumn through a container holding the internal standard under strictly defined conditions of temperature, pressure and flow rate. The elution of volatiles from the traps was accomplished directly into the oven of the gas chromatograph. The operating parameters of the system are discussed. This procedure allows the qualitative (and quantitative) determination of different volatile compounds present in the headspace above wines. The factors which influence the air-liquid partition of volatile compounds present in wine are also examined. |
