The Analysis of the Bitter and Other Flavour Compounds in Beer and Wort by Stir Bar Sorptive Extraction (SBSE) Followed by HPLC


App Note 5/2001

A new sample preparation technique – Stir Bar Sorptive Extraction (SBSE) was evaluated for the enrichment of hop-derived solutes in wort and beer. SBSE offers an effective, easy-handling and low cost opportunity for the isolation of organic solutes from aqueous matrices. A small stir bar, coated with polydimethylsiloxane is placed directly in the sample and stirred for about an hour. After sampling, the stir bar is placed in a thermal desorption unit for subsequent GC separation under mild conditions. Several hop-derived solutes can be elucidated and identified in this way. Alternatively, the stir bar can be desorbed by a liquid followed by HPLC analysis. This allows analysis of some of the thermally stable hop derived solutes. Both approaches are complementary in nature and give a quite complete profile of the hoppy flavor in beer. The SBSE approach has also been compared to the classical SPE-HPLC technique.