Fast GC-FID method for the analysis of primary hop essential oils

Analytical Session
Cheryl G Ermey, John I. Haas, Inc., Yakima, WA USA
Co-author(s): Joyce Carr, John I. Haas, Inc., Yakima, WA, USA

ABSTRACT: A modified rapid method has been developed for the analysis of hop essential oils by GC-FID based on rapid characterization of hop essential oils using gas chromatography–time-of-flight mass spectrometry. This method, which was published in the Journal of the American Society of Brewing Chemists (60(3):116, 2002), is able to successfully identify 40 key common essential oils. The author’s modification, which utilizes GC-FID, provides a rapid method for the identification of the four primary hop essential oils: myrcene, humulene, caryophyllene, and farnesene. The current ASBC method for GC analysis of hop oils results in a run time of 86 min. The fast GC method utilizes a smaller and more efficient DB-5 column with a run time of less than 9 min, resulting in a decreased GC analysis time of nearly 10-fold. This modified method works very well for the primary hops oils myrcene, humulene, caryophyllene, and farnesene. However, because of the dilute nature of the sample in the fast GC method, essential oils that occur at less than 1% (e.g., geraniol, linalool) may not be reliably quantitated. An adjustment in the sample dilution protocol may make it possible to include these lesser compounds.

Cheryl Ermey has a bachelor’s degree in biology, with a minor in chemistry, from Central Washington University in Ellensburg, WA. She has been employed by John I. Haas, Inc. in the Quality Assurance laboratory since 2008. Prior to working at Haas, Cheryl worked as a microbiology technician for Ag Health Labs in Sunnyside, WA, and as a chemistry technician for Battelle Toxicology Northwest in Richland, WA. She has several years of experience working with gas chromatography, both at Haas and at Battelle. Cheryl also spent five years as a volunteer firefighter with the West Valley Fire Department in Yakima County.