CHROMATOGRAPHIC ANALYSIS OF VOLATILE SULFUR-COMPOUNDS IN WINES USING THE STATIC HEADSPACE TECHNIQUE WITH FLAME PHOTOMETRIC DETECTION

This study describes the development of a method for determining eleve n sulphur compounds in wine, which takes into account that thiols are easily oxidizable. The equilibria of the analytes between air and aque ous ethanol were studied and optimised using static headspace gas chro matography in order to obtain the best sensitivities. The influences o f parameters such as temperature, time, ionic strength, headspace volu me and the volume of headspace injected were determined. A cryogenic t rap was used to concentrate the headspace analytes and they were chrom atographically analysed using GC temperature programming on a poly(eth ylene 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 th e sample. Recoveries were determined by the standard addition techniqu e 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.