High Performance Liquid Chromatographic Analysis of Hop Bittering Components in Hops, Hop Extracts, Wort, and Beer. E. J. Knudson and K. J. Siebert, The Stroh Brewery Co., Detroit, MI 48226. J. Am. Soc. Brew. Chem. 41:0051, 1983.

Simplex optimization was used for selecting optimal mobile phases for the high performance liquid chromatographic (HPLC) separation of iso-α-, α-, and β-acids from beer, wort, hops, and hop extracts. Two different eluants proved necessary for optimal separation of iso-α- and α-acids from beer and wort samples and of α- and β-acids from hops and hop extracts. These were chosen to permit rapid column conditioning and changeover when necessary. Both are solutions of methanol, acetonitrile, tetrahydrofuran, and water and contain 0.03M tetramethylammonium hydroxide and sufficient phosphoric acid to make the pH of the solution 6.8. Benzophenone and 4-methylbenzophenone were found to be suitable internal standards, and their use was determined by the type of HPLC column used. Results of the technique agreed with those of accepted methods for quantitation of iso-α-, α-, and β-acids.

Keywords: α-Acids, β-Acids, High performance liquid chromatography, Hop acids, Iso-α-acids, Simplex optimization