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Title Identification of Sulfur Compounds
Author Klukowska, Agata (Analytical Chemistry Group, Department of Chemistry, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark)
Institution Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark
Thesis level Master's thesis
Year 2009
Abstract This report describes the attempt to identify and quantify dimethyl sulfide (DMS) content in commercial beer and wort samples. Solid – phase microextraction together with gas chromatography-mass spectrometry (GC-MS) were applied for this purpose. DMS is one of the most abundant volatile sulfur compounds (VSC) with a strong sweet odor, often associated with cooked cabbage or sweet corn. The preferable DMS concentration in beer ranges from 30 μg/L to 100 μg/L, as within this boundaries it is detectable by human senses, but does not spoil the taste of a beer. The control of its level is required to assure that the appropriate concentration is maintained. Although the analysis seems straightforward, it can be challenging, as DMS is not added intentionally to the beer, but originates from different steps of beer production. Experimental part included instrument verification by measurements of solvents, qualitative analysis of sulfides and thiols and determination of DMS in beer and wort samples. The results from experiments indicated that good and reliable measurements can be done, however, in relatively high analytes concentrations. Evaluation of results revealed that DMS was quantified below the lower limit of analysis (LLA). Based on pooled calibration curves the LLA value was found to be approximately120 μg/L, whereas the typical DMS concentration in beer ranges from 14 to 144 μg/L. This means that obtained results are not reliable and can be significantly different from correct values. Additionally large variation of data on calibration curves was observed, what precluded the reliable determination of DMS concentration in wort samples
Imprint Technical University of Denmark (DTU) : Kgs. Lyngby, Denmark
Pages 143
Admin Creation date: 2011-01-06    Update date: 2011-01-06    Source: dtu    ID: 272305    Original MXD