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首页> 外文学位 >Method development in mass spectrometry: Ionic liquid matrices for MALDI-MS and reverse derivatization for DAG analysis.
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Method development in mass spectrometry: Ionic liquid matrices for MALDI-MS and reverse derivatization for DAG analysis.

机译：质谱方法的发展：用于MALDI-MS的离子液体基质和用于DAG分析的反向衍生化。

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摘要

The matrix plays an essential role in matrix-assisted laser desorption/ionization (MALDI). The major goal of the research described in this thesis is to develop a new matrix system with improved sample homogeneity and signal reproducibility that could be a substitute for the widely used solid matrices. Room temperature ionic liquids have high solubilizing power, negligible vapor pressure, and broad liquid range. They form homogeneous solutions with most analytes and promote their ionization. Ionic liquid matrices (ILMs) produce much improved signal reproducibility, which minimizes the time required to search for "sweet spots" that permit acquisition of high quality mass spectra, and facilitates the quantitative studies in MALDI. In this thesis, we report the advantages and limitations of ILMs with respect to solid matrices.; We utilized ILMs in the quantitative analysis of a single oligonucleotide, polypeptide, and small protein, taking advantage of their much-improved sample homogeneity. Good calibrations with high linearity and reproducibility can be achieved over a dynamic range of two orders of magnitude even when the internal standard has a structure different from those of the analytes. We further quantified the peptides in simple and complex mixtures. The good linearity and reproducibility for the calibration curves were retained; however, the dynamic range for quantification was reduced to one order of magnitude for complex mixture analysis.; We then applied ILMs for analysis of phospholipids. Higher signal intensity, smaller spot size, improved spot homogeneity, better signal reproducibility and comparable or better detection limits, and a lower extent of prompt fragmentation were achieved with ILMs compared to the crystalline matrix 2,5-dihydroxybenzoic acid (2,5-DHB).; We also sought improvement in a specific analysis problem by developing a derivatization approach to improve quantification of diacyl glycerols (DAGs) using electrospray ionization mass spectrometry (ESI/MS). A quaternary ammonium cation was introduced to neutral DAG molecules by using N-chlorobetainyl chloride. The permanent charge introduced in the derivatized DAGs allowed us to achieve two orders of magnitude higher signal intensities than with their underivatized sodium adducts. We demonstrated that this reverse derivatization is suitable for the quantification of DAG molecular species in biological samples when using ESI/MS.
机译：基质在基质辅助的激光解吸/电离（MALDI）中起着至关重要的作用。本文所述研究的主要目标是开发一种具有改善的样品均一性和信号重现性的新型基质系统，以替代广泛使用的固体基质。室温离子液体具有较高的增溶能力，可忽略的蒸气压和宽广的液体范围。它们与大多数分析物形成均质溶液并促进其离子化。离子液体基质（ILM）可以大大提高信号的可再现性，从而最大程度地减少了搜索“甜点”所需的时间，这些“甜点”可以采集高质量的质谱图，并且有助于MALDI中的定量研究。在本文中，我们报告了ILM在固体基质方面的优势和局限性。我们利用ILM对单个寡核苷酸，多肽和小蛋白质进行定量分析，充分利用了它们的样品同质性。即使内标的结构与分析物的结构不同，也可以在两个数量级的动态范围内实现具有高线性和可重复性的良好校准。我们进一步定量了简单和复杂混合物中的肽。保留了校准曲线的良好线性和重现性；但是，复杂混合物分析的定量动态范围减小到一个数量级。然后，我们将ILM用于分析磷脂。与结晶基质2,5-二羟基苯甲酸（2,5-DHB）相比，使用ILM可获得更高的信号强度，更小的斑点尺寸，更佳的斑点均质性，更好的信号重现性和可比或更好的检测限以及更低的即时裂解程度）。我们还寻求通过开发一种衍生化方法来改进特定分析问题的方法，该方法可使用电喷雾电离质谱（ESI / MS）改进二酰基甘油（DAG）的定量。通过使用N-氯甜菜碱酰氯将季铵阳离子引入中性DAG分子。衍生化DAG中引入的永久电荷使我们获得的信号强度比未衍生化钠加合物高两个数量级。我们证明了这种反向衍生化方法适用于使用ESI / MS定量生物样品中的DAG分子种类。

著录项

  • 作者

    Li, Ying.;

  • 作者单位

    Washington University in St. Louis.;

  • 授予单位 Washington University in St. Louis.;
  • 学科 Chemistry Analytical.
  • 学位 Ph.D.
  • 年度 2006
  • 页码 200 p.
  • 总页数 200
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化学;
  • 关键词

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