Chromatographic analysis of volatile sulphur compounds in wines using the static headspace technique with flame photometric detection

This study describes the development of a method for determining eleven sulphur compounds in wine, which takes into account that thiols are easily oxidizable. The equilibria of the analytes between air and aqueous ethanol were studied and optimised using static headspace gas chromatography in order to obtain the best sensitivities. The influences of parameters such as temperature, time, ionic strength, headspace volume and the volume of headspace injected were determined. A cryogenic trap was used to concentrate the headspace analytes and they were chromatographically analysed using GC temperature programming on a poly(ethylene glycol) capillary column with FPD detection at 394 nm. The power relationship was observed between the chromatographic response and a concentration of sulphur compounds in the range 2-150 mu g l(-1) in the sample. Recoveries were determined by the standard addition technique and were higher than 90% for sulphides and disulphides and close to 80% for thiols. The overall method was successfully used to determine the sulphur compounds in white and red wines.