Characterization of Fast Dissociation Pathways of Polyatomic Ions

亚利桑那大学的Vicki Wysocki教授得到了分析和表面化学项目的支持，研究多肽的快速断裂。这项工作的基本问题是，为什么我们能够在典型的质谱实验的时间尺度上看到显著的碎片，而现有的最佳理论表明，碎片应该只在更长的时间尺度的质谱实验中观察到。总体假设是，存在快速裂解途径（通过先前未描述的反应中间体），导致产品在时间尺度上的出现，允许质谱仪在微秒或更短的实验时间框架内观察。PI使用表面碰撞结合基质辅助激光解吸电离（以及后来的电喷雾电离）和飞行时间质谱来探测这些过程。这个问题是通过改变表面的性质和弹丸的性质来研究的。与PNNL的Futrell小组和德克萨斯理工学院的理论家Hase建立了良好的合作关系。学生在物理分析化学和质谱方面接受了良好的培训。肽片段是蛋白质组学中常用的方法，质谱法在蛋白质组学中起着至关重要的作用。从基本层面理解碎片化可以带来更有效的分析工具和用于数据库目的的预测模型。

Professor Vicki Wysocki of the University of Arizona is supported by the Analytical and Surface Chemistry Program to study the fast fragmentation of peptides. The fundamental question in this work is one that asks why we are able to see significant fragmentation on the timescale of the typical mass spectrometry experiment, while the best theory available suggests that fragments should only be observed with longer timescale MS experiments. The overall hypothesis is that there are fast fragmentation pathways (via previously undescribed reactive intermediates) that lead to the appearance of products on timescales that allow observation by mass spectrometers with microsecond or shorter experimental timeframes. The PI uses surface collisions in combination with matrix-assisted laser desorption ionization (and later electrospray ionization) and time-of-flight mass spectrometry to probe these processes. The question is studied by varying both the nature of the surface and the nature of the projectiles. There is a well-established collaboration with the Futrell group at PNNL and the theorist Hase at Texas Tech. Students are well-trained in physical-analytical chemistry and mass spectrometry.Fragmentation of peptides is commonly used in proteomics, in which mass spectrometry plays a critical role. Understanding fragmentation at a fundamental level can lead to more efficient analytical instruments, and predictive models for database purposes.