Determination of Tyrosol, 2-Phenethyl Alcohol, and Tryptophol in Beer by High-Performance Liquid Chromatography

Tyrosol, 2-phenethyl alcohol, and tryptophol are three by-products of yeast fermentation. A reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed for their simultaneous determination. The separation was carried out on a C(18) column (250 x 4.6 min i.d., 5 mu m). using a gradient elution and ultraviolet detection at 210 nm. Satisfactory precision was obtained, with percent relative standard deviation <0.3% for peak areas (n = 6). Recovery rates were 98.2-100.9% due to the simple treatment and good resolution. The RP-HPLC method, which may be applied for quality control in the brewery, was simple, accurate, and reproducible. Nine types of beer and six fermenting wort samples were analyzed.