Quantitation of 8-prenylnaringenin, a novel phytoestrogen in hops (Humuluslupulus L.), hop products, and beers, by benchtop HPLC-MS using electrospray ionization

8-Prenylnaringenin (8-PN), a potent phytoestrogen, present in hops (Humulus lupulus L.), hop products, and most beers, exhibits an estrogenic activity greater than that of any of the known phytoestrogens. A sensitive, selecti ve, and robust analytical method, based on HPLC-MS (High performance Liquid Chromatography - Mass Spectrometry) using atmospheric pressure electrospra y ionization, has been developed for systematic investigation of the develo pment and the localization of this estrogenic trait in the hop plant, as we ll as for quantitative determination of 8-PN in hop varieties, hop products , and beers. Excellent linearity was obtained in the range of 3.7-2,200 mu g L-1 (gamma = 0.9999, n = 7) and the limit of detection was ca, 1 mu g L-1 Recoveries were between 93.8 % (110 mu g L-1) and 96.5 % (370 mu g L-1) fo r hop products, and between 63.4 % (18.5 mu g L-1) and 72.8 % (37 mu g L-1) for beers. Good precision was achieved with relative standard deviations o f less than 5 % within-day (n = 6) and less than 10 % from-day-to-day (n = 18).