Analysis of xanthohumol and isoxanthohumol in different hop products by liquid chromatography-diode array detection-electrospray ionization tandem mass spectrometry

An analytical methodology based on the sample extraction with methanol/formic acid by ultra-sonication and subsequent analysis by highperformance liquid chromatography with diode array detection is proposed for the determination of xanthohumol (XN) and isoxanthohumol (IXN) in different hop products. The identity of the compounds was confirmed by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry in positive ion mode. The performance of the method was assessed by the evaluation of parameters such as absolute recovery, repeatability, linearity and limits of detection and quantitation. This methodology was applied to investigate the impact of the extraction process of the hop products on the amount of xanthohumol and isoxanthohumol. The ethanolic extract revealed to be the hop product richest in xanthohumol (3.75 +/- 0.05 g1100 g) relatively to the pellets (0.62 0.01 g1100 g) and supercritical CO2 extract (0.089 +/- 0.001 g/100 g). (C) 2006 Elsevier B.V. All rights reserved.