The importance of hops (the flowers of Humulus lupulus) as food and an herbal remedy is reflected by a large number of analytical methods published. However, supercritical fluid chromatography, a highly efficient, rapid, and "green" separation technique, has not been considered for hops samples so far. This prompted us to establish the first supercritical fluid chromatography-based protocol for the separation, identification, and quantitation of five prenylated constituents of hops. Hulupinic acid (1: ), a prominent oxidation product of hop acids, three flavanones, i.e., 8-prenylnaringenin (2: ), 6-prenylnaringenin (3: ), and isoxanthohumol (4: ), as well as the chalcone xanthohumol (5: ) could be baseline separated in less than 5 minutes using a Viridis BEH 2-EP column (3.0 × 100 mm; 1.7 µm particle size) and a mobile phase consisting of CO2 and isopropanol. Good results regarding selectivity, accuracy (recovery rates: 85.0 - 113.1%), precision (intra-day ≤ 2.1%, inter-day ≤ 3.5%), and linearity (R2 ≥ 0.99) were obtained for both photodiode array and mass detection. The lowest detection limit at 220 nm was at 0.1 µg/mL (1, 3: , and 4: ), with mass detection even at 0.001 µg/mL (4: ). As an application example of the validated method, the five hops constituents were quantified in three dietary supplements, one herbal medicinal product, and two batches of hop flowers (Lupuli flos). In most samples analyzed, the major component was 5: (0.01 - 1.02%), whereas the major component in Lupuli flos samples was compound 1: (0.12 - 0.21%). This protocol offers a fast and environmentally friendly alternative to liquid chromatography for the quality control of hops.

中文翻译：

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使用超高效超临界流体色谱法定量分析商业啤酒花样品中的异戊二烯化成分

啤酒花（Humulus lupulus 的花）作为食物和草药的重要性体现在大量发表的分析方法中。然而，超临界流体色谱是一种高效、快速、“绿色”的分离技术，目前尚未考虑用于啤酒花样品。这促使我们建立了第一个基于超临界流体色谱的方案，用于啤酒花的五种异戊二烯化成分的分离、鉴定和定量。Hulupinic acid (1: )，啤酒花酸、三种黄烷酮，即 8-异戊二烯基柚皮素 (2: )、6-异戊二烯基柚皮素 (3: ) 和异黄腐酚 (4: ) 以及查耳酮黄腐酚 ( 5: ) 可以使用 Viridis BEH 2-EP 色谱柱（3.0 × 100 mm；1. 7 µm 粒径）和由 CO2 和异丙醇组成的流动相。光电二极管阵列和质量检测在选择性、准确度（回收率：85.0 - 113.1%）、精密度（日内≤ 2.1%，日间≤ 3.5%）和线性（R2 ≥ 0.99）方面均取得了良好的结果。220 nm 处的最低检测限为 0.1 µg/mL（1、3: 和 4: ），质量检测甚至在 0.001 µg/mL (4: )。作为验证方法的应用示例，对三种膳食补充剂、一种草药产品和两批啤酒花 (Lupuli flos) 中的五种啤酒花成分进行了定量分析。在分析的大多数样品中，主要成分为 5: (0.01 - 1.02%)，而 Lupuli flos 样品中的主要成分是化合物 1: (0.12 - 0.21%)。