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Infrared multiple photon dissociation - mass spectrometry of monosaccharides, disaccharides, trisaccharides and their derivatives for isomeric differentiation

机译：红外多光子解离-质谱用于单糖，二糖，三糖及其衍生物的异构分化

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摘要

The structural study of carbohydrates and their derivatives remains challenging due to the large number of possible isomers. As they have identical masses, these isomers cannot be differentiated even by high-resolution mass spectrometry (MS). In order to gain more structural information, their dissociation patterns in MS are of great interest. The central goal of our research is to systematically study the infrared multiple photon dissociation - mass spectrometry (IRMPD-MS) of monosaccharides, disaccharides, trisaccharides and their derivatives.;Here, a tunable CO2 laser and a tunable optical oscillator parametric (OPO) were employed to induce IRMPD of mass-selected carbohydrates, taking advantage of their distinct tuning ranges (a CO2 laser: 925-1085 cm-1 and an OPO: 2500-4000 cm-1). The carbohydrate molecules were ionized by electrospray ionization (ESI) and subsequently fragmented by a focused IR beam in an ion trap. A commercial Fourier transform ion cyclotron resonance (FTICR) mass spectrometer was used in conjunction with the CO2 laser, and a quadrupole ion trap - time-of-flight (QIT-TOF) was coupled with the OPO.;In Chapter 3, monosaccharide isomers were probed by wavelength-dependent IRMPD with a tunable CO2 laser. It was shown that isomeric variants of lithiated monosaccharides could be distinguished with this approach, but deprotonated analytes had nearly identical dissociation spectra. Chapter 4 involved the study of hexoses, Nacetylhexosamines, hexosamine sulfates which were structurally elucidated by IRMPD spectroscopy with a tunable OPO. The IRMPD spectra of monosaccharide derivative isomers displayed remarkable differences in the O-H and N-H stretching IR region. The results also suggested that gas-phase conformation, affected by ionization state or chemical modifications, exhibited diagnostic IR absorbances and characteristic photodissociation behavior. In Chapter 5, a top-down approach was employed to characterize isomeric variants of glucose-based trisaccharides. The trisaccharides were fragmented and mass selected to the key disaccharide fragments. The linkage and anomericity of the disaccharide substructures were then differentiated by wavelengthdependent IRMPD using the CO2 laser. On the basis of these results, variablewavelength IRMPD provides a promising method to characterize carbohydrate structures and thus differentiate isomer variants by mass spectrometry.
机译：由于大量可能的异构体，碳水化合物及其衍生物的结构研究仍然具有挑战性。由于它们具有相同的质量，因此即使通过高分辨率质谱（MS）也无法区分这些异构体。为了获得更多的结构信息，它们在MS中的解离模式引起了人们的极大兴趣。我们研究的主要目标是系统地研究单糖，二糖，三糖及其衍生物的红外多光子离解质谱（IRMPD-MS）。在此，使用了可调式CO2激光器和可调式光学振荡器参数（OPO）。利用其独特的调节范围（CO2激光：925-1085 cm-1和OPO：2500-4000 cm-1）诱导大量选择的碳水化合物的IRMPD。碳水化合物分子通过电喷雾电离（ESI）电离，随后在离子阱中被聚焦的IR束破碎。商用傅里叶变换离子回旋共振（FTICR）质谱仪与CO2激光器结合使用，四极杆离子阱-飞行时间（QIT-TOF）与OPO耦合;在第3章中，单糖异构体通过波长可调的IRMPD和可调式CO2激光对它们进行探测。结果表明，锂化单糖的异构体变体可以通过这种方法加以区分，但是去质子化的分析物具有几乎相同的解离光谱。第4章研究了己糖，N-乙酰己糖胺，硫酸己糖硫酸盐，并通过IRMPD光谱和可调OPO对其结构进行了阐明。单糖衍生物异构体的IRMPD光谱在O-H和N-H拉伸IR区域显示出显着差异。结果还表明，气相构象受电离状态或化学修饰的影响，表现出诊断性IR吸光度和特征性的光解离行为。在第5章中，采用了自上而下的方法来表征葡萄糖基三糖的异构体变体。将三糖片段化，然后选择关键的二糖片段质量。然后，使用CO2激光通过波长依赖的IRMPD区分二糖亚结构的键合和异头性。基于这些结果，可变波长IRMPD提供了一种有前途的方法来表征碳水化合物结构，从而通过质谱法区分异构体变体。

著录项

  • 作者

    Tan, Yanglan.;

  • 作者单位

    University of Florida.;

  • 授予单位 University of Florida.;
  • 学科 Biochemistry.;Chemistry.
  • 学位 Ph.D.
  • 年度 2014
  • 页码 146 p.
  • 总页数 146
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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