Abstract This is the first study to employ a reaction flow (RF) HPLC column of a short 5 cm length to identify antioxidants in a variety of complex samples represented by tea, utilising simultaneous multiplexed detection techniques. The detection responses included: underivatised UV at 280 nm, underivatised fluorescence detection (FLD) and a post column derivatisation (PCD) colorimetric response for antioxidants via the ferric reducing antioxidant power (FRAP) assay. Both similarities and differences in the chromatograms obtained using the three detection modes highlight the power of multiplexed detection. The main findings from the bioactive profiling include: the Fruit of the Forest tea contains the lowest level of antioxidants and is clearly distinct from the other three teas which are based on Camellia sinensis. The antioxidants detected in the green tea and the two black teas are similar. The green tea contains a higher concentration of the two main antioxidants that eluted at 4.0 and 5.7 min. The simplicity of sample analysis and chemical profiling using RF columns and selective detection was the focus of this study via the analysis of antioxidants in tea using the FRAP reagent. The main advantage of RF-PCD is the ability to split flows for simultaneous detection with minimal post column dead volume contributions, making peak matching between detectors much easier. To date, few studies exploit the power of RF-PCD multiplexed detection to differentiate and identify bioactive compounds in various complex samples. Applications of the approach developed in this study may include antioxidant screening and profiling of natural products, foods and beverages.

中文翻译：

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使用结合反应流 HPLC 柱的铁还原抗氧化能力测定法对复杂茶样品进行生物活性筛选，用于柱后衍生

摘要 这是第一项使用 5 cm 短反应流 (RF) HPLC 色谱柱，利用同步多重检测技术鉴定以茶为代表的各种复杂样品中的抗氧化剂的研究。检测响应包括：280 nm 处未衍生化的 UV、未衍生化的荧光检测 (FLD) 和通过铁还原抗氧化能力 (FRAP) 测定对抗氧化剂的柱后衍生化 (PCD) 比色响应。使用三种检测模式获得的色谱图的异同突出了多重检测的能力。生物活性分析的主要发现包括：森林之果茶含有最低水平的抗氧化剂，与其他三种基于山茶花的茶明显不同。绿茶和两种红茶中检测到的抗氧化剂相似。绿茶含有较高浓度的两种主要抗氧化剂，在 4.0 和 5.7 分钟时洗脱。通过使用 FRAP 试剂分析茶叶中的抗氧化剂，使用 RF 色谱柱和选择性检测简化样品分析和化学分析是本研究的重点。RF-PCD 的主要优点是能够以最小的柱后死体积贡献分流进行同时检测，从而使检测器之间的峰匹配更加容易。迄今为止，很少有研究利用 RF-PCD 多重检测的能力来区分和识别各种复杂样品中的生物活性化合物。本研究中开发的方法的应用可能包括天然产品、食品和饮料的抗氧化剂筛选和分析。