Determination of flavour compounds in beer using stir-bar sorptive extraction and solid-phase microextraction

The analysis of volatile compounds in beer is important for quality control in the brewing industry. In this study, stir-bar sorptive extraction (SBSE) and solid-phase microextraction (SPME), two solvent-less enrichment techniques, were applied in combination with gas chromatography flame ionization detection (GC/FID) for the determination of four flavour compounds (isoamyl acetate, ethyl hexanoate, benzaldehyde, myrcene) in beer. Limits of detection, linearity and repeatability of both methods were determined using standard ethanol solutions, while accuracy was determined by conducting recovery tests on commercial beer samples. Both methods were characterized by high linearity (r > 0.996) and repeatability (RSD = 1.76-10.66%). When both methods were compared, higher recoveries were obtained by SBSE, with limits of detection 1.8-2.8 times lower compared with SPME. In the analysis of commercial beer samples using both methods, SBSE analysis resulted in higher recoveries, therefore demonstrating promise for the analysis of beer volatiles. Copyright (c) 2015 The Institute of Brewing & Distilling