VIEW ARTICLE    DOI: 10.1094/ASBCJ-45-0070

Simultaneous Analysis of Hop Bittering Components by High-Performance Liquid Chromatography. III. Development of On-Line Sample Enrichment by Precolumn Switching. M. Ono, Y. Kakudo, K. Nagami, and J. Kumada, Research Institute of Alcoholic Beverages and Fermentation Technology, Suntory Ltd., Osaka 618 Japan; and Suehiro Ueda, Analytical Applications Department, Shimadzu Corporation, Kyoto, 604 Japan. J. Am. Soc. Brew. Chem. 45:0070, 1987.

A fully automated method based on on-line sample enrichment by precolumn switching was developed for determination of the nine main hop bittering components in wort and beer. A combination of two columns was used: a tetramethylolmethanetriacrylate type for trapping and an octadecylated silica type for final separation. The on-line method was compared with the conventional method based on off-line sample enrichment (liquid-liquid extraction and concentration). Both methods showed nearly the same product recoveries for iso-α-acids, α-acids, and β-acids. This sample enrichment method-an automated high-performance liquid chromatography system-is distinguished by simple, rapid operation and by good reproducibility, and it is eminently suited for automated routine analysis in the brewery. This method was semiautomatically applied to the determination of hop bittering components in hops and hop products.

Keywords: α-Acids, Automated high-performance liquid chromatography, β-Acids, Beer, Iso-α-acids, Wort