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首页> 外文学位 >Part I. Isocratic and gradient elution reversed-phase liquid chromatography for the estimation of the hydrophobicity parameter log k(',w): Applications to newer generation stationary phases. Part II. Planar electrochromatographic instrumental design and results.
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Part I. Isocratic and gradient elution reversed-phase liquid chromatography for the estimation of the hydrophobicity parameter log k(',w): Applications to newer generation stationary phases. Part II. Planar electrochromatographic instrumental design and results.

机译：第一部分。等度和梯度洗脱反相液相色谱法，用于估计疏水性参数log k（'，w）：在新一代固定相中的应用。第二部分平面电色谱仪器的设计和结果。

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摘要

The first half of this dissertation (Chapters 1--3) will discuss reversed-phase liquid chromatographic (RPLC) estimations of hydrophobicity. The RPLC retention values in purely aqueous mobile phases are used as measures of hydrophobicity. Unfortunately the accepted way of deriving these estimations is inaccurate. These values are normally obtained by performing isocratic chromatography through a limited range of mobile phase modifier concentrations (somewhere between 30%--70% modifier) and using the linear relationship between the logarithm of retention and modifier concentration to extrapolate a retention value for a purely aqueous mobile phase (log k' w). This linear relationship breaks down at low concentrations of modifier resulting in extrapolated values not representative of the actual chromatographic values. We have investigated newer types of RPLC columns using polar-embedded and polar-endcapped stationary phases for their ability to produce a more linear relationship throughout the range of modifier concentrations, therefore reducing error from extrapolation procedures. This work includes comparisons to other chromatographic retention modeling equations, as well as using gradient RPLC to obtain these estimations of hydrophobicity.; The second half of this dissertation (Chapters 4--7) describes the development of instrumentation for planar electrochromatography (PEC). PEC is a new methodology for thin layer chromatography (TLC) where the solvent is pushed through a TLC plate by electroosmotic flow (EOF) rather than capillary action. This allows faster flow rates and better-predicted chromatographic figures of merit. Initial instrument design had major problems due to joule heating, solvent evaporation and a vertical format. Instrumentation has evolved with horizontal formats, closed systems to eliminate solvent evaporation, and external pressurization for correct voltage profiles across a TLC plate. We now understand the reasons for early instrumental hindrances and have continually redesigned the instrument to combat each obstacle. The latest design has achieved the predicted linear voltage drop of the applied field and hence, consistent EOF. Further proving the efficacy of this technique, initial studies with a fluorescent marker visually prove the correct solvent flow profiles determined with our voltage readers.
机译：本论文的前半部分（第1--3章）将讨论疏水性的反相液相色谱（RPLC）估计。纯水性流动相中的RPLC保留值用作疏水性的量度。不幸的是，得出这些估计的公认方法是不准确的。这些值通常是通过在有限范围的流动相改性剂浓度（介于30％-70％的改性剂之间）进行等度色谱法并使用保留对数和改性剂浓度之间的线性关系来推断纯的保留值而获得的水性流动相（log k'w）。这种线性关系在低浓度的改性剂下会分解，导致推断出的值不代表实际的色谱值。我们已经研究了使用极性嵌入和极性封端的固定相的新型RPLC色谱柱，因为它们能够在整个改性剂浓度范围内产生更线性的关系，从而减少了外推程序的误差。这项工作包括与其他色谱保留模型方程的比较，以及使用梯度RPLC获得疏水性的这些估计。本论文的第二部分（第4--7章）描述了平面电色谱（PEC）仪器的发展。 PEC是用于薄层色谱（TLC）的新方法，其中通过电渗流（EOF）而不是毛细管作用将溶剂推过TLC板。这样可以实现更快的流速和更好的色谱品质因数预测。由于焦耳加热，溶剂蒸发和垂直格式，最初的仪器设计存在主要问题。仪器已经发展成水平格式，封闭系统以消除溶剂蒸发，并通过外部加压来确保TLC板上的电压分布正确。现在，我们了解了早期乐器障碍的原因，并不断重新设计该乐器以克服每个障碍。最新的设计已实现了所施加磁场的预计线性电压降，因此实现了一致的EOF。为了进一步证明该技术的有效性，使用荧光标记的初步研究从视觉上证明了使用我们的电压读取器确定的正确的溶剂流量曲线。

著录项

  • 作者

    Tate, Peter Anthony.;

  • 作者单位

    The Florida State University.;

  • 授予单位 The Florida State University.;
  • 学科 Chemistry Analytical.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 126 p.
  • 总页数 126
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化学;
  • 关键词

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