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首页> 外文学位 >Supercritical fluid extraction directly coupled with reversed phase liquid chromatography for quantitative analysis of analytes in complex matrices.
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Supercritical fluid extraction directly coupled with reversed phase liquid chromatography for quantitative analysis of analytes in complex matrices.

机译：超临界流体萃取直接与反相液相色谱结合用于定量分析复杂基质中的分析物。

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摘要

The purpose of this research was to design a simple, novel interface for on-line coupling of Supercritical Fluid Extraction (SFE) with High Performance Reversed Phase Liquid Chromatography (HP-RPLC), and to explore its ability for quantitative analysis of analytes in different matrices.; Based on this hyphenated technique, a method for the extraction and analysis of hyperforin in St. John's Wort was developed under air/light free conditions. Hyperforin is a major active constituent in the antidepression herbal medicine--- Hypericum perforatum (St. John's Wort). Mass spectral data on the extract confirmed the presence of the major degradation compounds of hyperforin (i.e. furohyperforin and two of its analogues). Thus, the degradation process must have occurred during plant drying or storage.; We then extended the interface's application to an aqueous sample by using a liquid-fluid extraction vessel. Quantitative extraction and transfer were achieved for the target analytes (progesterone, phenanthrene, and pyrene) spiked in water, as well as in real samples (urine and environmental water).; The last phase of our work explored the disadvantages/limitations of this hyphenated technique through the analysis of more highly polar phenolic compounds in grape seeds. Five types of SFE trapping adsorbent materials were evaluated in an effort to enhance the collection efficiency for the polar components. Pure supercritical CO2 was used first to remove the less polar oil in the seeds. Then methanol-modified CO2 was used to remove the polar components (e.g. phenolic compounds). Catechin and epicatechin (90%) were exhaustively extracted out of the de-oiled seed after 240 minutes with 40% methanol as modifier. Both singly linked (B-type) and doubly linked (A-type) procyanidins were identified by LC-ESI-MS, as well as their galloylated derivatives. (Abstract shortened by UMI.)
机译：这项研究的目的是设计一个简单，新颖的界面，用于超临界流体萃取（SFE）与高性能反相液相色谱（HP-RPLC）的在线耦合，并探索其对不同分析物进行定量分析的能力矩阵。基于这种联用技术，开发了一种在无空气/无光条件下提取和分析圣约翰草中超forin的方法。 Hyperforin是抗抑郁草药Perforatum（St. John's Wort）的主要活性成分。提取物上的质谱数据证实了金丝桃素主要降解化合物的存在（即呋喃妥因及其两个类似物）。因此，降解过程必须在植物干燥或储存过程中发生。然后，我们使用液-液萃取容器将界面的应用范围扩展至水性样品。对加标在水中以及实际样品（尿液和环境水）中的目标分析物（孕酮，菲和pyr）进行了定量萃取和转移。我们工作的最后阶段是通过分析葡萄种子中更高极性的酚类化合物来探索这种联用技术的缺点/局限性。为了提高极性组分的收集效率，对五种类型的SFE捕集吸附材料进行了评估。首先使用纯超临界CO2去除种子中极性较小的油。然后使用甲醇改性的CO2去除极性组分（例如酚类化合物）。 240分钟后，以40％甲醇为改性剂，从脱油的种子中彻底提取儿茶素和表儿茶素（90％）。通过LC-ESI-MS鉴定了单链（B型）和双链（A型）原花青素，以及它们的没食子酸酯化衍生物。 （摘要由UMI缩短。）

著录项

  • 作者

    Wang, Zhenyu.;

  • 作者单位

    Virginia Polytechnic Institute and State University.;

  • 授予单位 Virginia Polytechnic Institute and State University.;
  • 学科 Chemistry Analytical.
  • 学位 Ph.D.
  • 年度 2004
  • 页码 139 p.
  • 总页数 139
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化学;
  • 关键词

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