Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic.
J Chromatogr A. 2009 Oct 23;1216(43):7249-57. doi: 10.1016/j.chroma.2009.09.022. Epub 2009 Sep 12.
Hops contain a wide range of polyphenolic compounds with antioxidant properties divided in various chemical classes. These compounds are detected in hop extracts and also in beer as its main product. Based on the careful optimization of column type, column packing, mobile phase composition and gradient steepness, two high-performance liquid chromatography-mass spectrometry (HPLC/MS) methods have been developed. The first method using Purospher Star RP-8e column and the gradient of aqueous acetonitrile containing 0.3% formic acid is optimized for the separation of low polar polyphenolic compounds, while the second one with Zorbax SB-CN column is used for more polar hops and beer components. In this work, more compounds are detected in comparison to previous reports. In total, 49 low polar and 37 polar compounds are detected in studied samples and their molecular weights are determined based on atmospheric pressure chemical ionization (APCI) mass spectra. Some compounds are identified based on the interpretation of their full scan and tandem APCI mass spectra, retention behavior and UV spectra, while the full structure elucidation of other species still requires further research. The quantitation of xanthohumol related prenylflavonoids and bitter acids is done with two detection techniques (APCI-MS and UV detection) providing comparable results. Both compound classes (i.e., prenylflavonoids and bitter acids) are separated and quantitated in a single HPLC run, where numerous other polyphenolics are detected as well.
啤酒花含有多种具有抗氧化特性的多酚类化合物，可分为不同的化学类别。这些化合物存在于啤酒花提取物中，也是啤酒的主要产品。本研究基于对柱类型、柱填充剂、流动相组成和梯度斜率的仔细优化，开发了两种高效液相色谱-质谱（HPLC/MS）方法。第一种方法使用 Purospher Star RP-8e 柱和含有 0.3%甲酸的水-乙腈梯度来优化分离低极性多酚化合物，而第二种方法则使用 Zorbax SB-CN 柱来分离更具极性的啤酒花和啤酒成分。与之前的报道相比，本研究中检测到了更多的化合物。在研究样品中总共检测到 49 种低极性和 37 种极性化合物，并根据大气压化学电离（APCI）质谱确定其分子量。一些化合物是根据其全扫描和串联 APCI 质谱、保留行为和紫外光谱的解释来鉴定的，而其他物质的全结构解析仍需要进一步研究。利用两种检测技术（APCI-MS 和 UV 检测）对黄腐酚相关的类黄酮和苦味酸进行定量分析，结果相当。这两种化合物类别（即类黄酮和苦味酸）在单个 HPLC 运行中进行分离和定量，同时还检测到许多其他多酚类化合物。
