Comparison of the content of volatile sulphur-containing compounds in Slovak beers by the SPME method.

A comparison of volatile sulphur-containing compounds in Slovak beers was performed. These compounds, due to their low sensory threshold, and powerful and often unpleasant characteristics, can cause off-odours even in trace amounts. A wide variety of sulphur compounds were identified in the beers; the most important ones include dimethyl sulphide, dimethyl disulphide, dimethyl trisulphide, ethanethiol, ethyl thioacetate, methanethiol, methionol, methyl thioacetate, 3-methylthio propylacetate and carbon disulphide. In the first step, adsorption conditions, such as temperature, time, sample volume and addition of salts, were optimised. The content of volatile sulphur-containing compounds was measured using headspace solid-phase micro-extraction (SPME) coupled with gas chromatography and flame photometric detection (GC-FPD). Two internal standards were used - ethyl methyl sulphide and 1-propyl thioacetate. Differences in the profiles of individual compounds in different beer brands as well as differences in the amounts of sulphur-containing compounds in beers with different gravity were found.A comparison of volatile sulphur-containing compounds in Slovak beers was performed. These compounds, due to their low sensory threshold, and powerful and often unpleasant characteristics, can cause off-odours even in trace amounts. A wide variety of sulphur compounds were identified in the beers; the most important ones include dimethyl sulphide, dimethyl disulphide, dimethyl trisulphide, ethanethiol, ethyl thioacetate, methanethiol, methionol, methyl thioacetate, 3-methylthio propylacetate and carbon disulphide. In the first step, adsorption conditions, such as temperature, time, sample volume and addition of salts, were optimised. The content of volatile sulphur-containing compounds was measured using headspace solid-phase micro-extraction (SPME) coupled with gas chromatography and flame photometric detection (GC-FPD). Two internal standards were used - ethyl methyl sulphide and 1-propyl thioacetate. Differences in the profiles of individual compounds in different beer brands as well as differences in the amounts of sulphur-containing compounds in beers with different gravity were found.