Determination of Existing and Potential Dimethyl Sulphide in Red Wines by Gas Chromatography Atomic Emission Spectroscopy

✍ Scribed by H.B. Swan

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 180 KB
• Volume: 13
• Category: Article
• ISSN: 0889-1575
• DOI: 10.1006/jfca.2000.0888

✦ Synopsis

The activity of micro-organisms in food and beverages can produce dimethylsulphide (DMS), characteristic of composition and condition. DMS and potential DMS derived from precursor compounds in red wines have been analysed by gas chromatography with the atomic emission detector (GC-AED). The AED was found to be a speci"c and sensitive instrument for volatile sulphur compound analysis which allowed con"rmation of sulphur response by observation of its characteristic emission spectra. DMS present in wines was purged from diluted samples to an adsorbent composed of gold-coated glass wool. This was thermally desorbed to a valving and cryogenic trap system coupled to the GC-AED which also provided permeated methylethylsulphide as an internal standard. This con"guration was also suitable for the analysis of CS present in the wines. For DMS a coe$cient of variation of 3% was obtained from replicate analyses of wine samples between 30 and 200 g/L, with a limit of detection of 1 g/L using 1/1000 diluted samples. DMS precursor was assessed using 0.5, 1.0 and 2.0 M NaOH at 803C to liberate DMS. Di!erent amounts of DMS were released from the various samples using the three alkaline strengths, necessitating that a standard set of conditions be adhered to in order to gauge the potential for DMS release during storage.