A NOVEL HIGH-CAPACITY ION TRAP-QUADRUPOLE TANDEM MASS SPECTROMETER

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 中心，不一定是研究者的机构。 我们描述了一种原型串联质谱仪，其设计用于将链接扫描分析的效率提高>100倍于传统的链接扫描仪器。质谱仪的关键元件是一种新型的高离子容量离子阱，其与四极碰撞室和四极质量分析器（即TrapqQ配置）串联配置组合。该离子阱可以存储>106个离子，而不会显著降低其性能。阱的当前质量分辨率为100450对于范围800中的离子的半峰全宽4000 m/z，产生1020 m/z选择窗口，用于在任何给定时间喷射到碰撞室中的离子。质谱仪检测肽的灵敏度在低飞摩尔范围内。我们可以设想对仪器进行相对直接的修改，以提高其分辨率和灵敏度。我们测试了串联质谱仪用于收集存储在阱中的所有离子的前体离子光谱，并证明我们可以选择性地检测非磷酸化肽混合物中的磷酸化肽。基于这个原型仪器，我们计划构建一个功能齐全的模型的质谱仪检测蛋白质上的修饰位点，并分析其丰度与高速和灵敏度。 目前，我们正在测试第二代仪器耦合到一个正交的飞行时间分析仪的母离子和碎片离子的准确质量读数。为了实现这一目标，我们有： 我们已经优化了高容量的离子阱和相邻的碰撞池，通过合并一个圆柱形外壳来使用不同的气体。 这将使我们能够控制每个区域的压力，并允许我们在每个区域使用不同的气体以更好地冷却离子。 我们改变了我们原来的四极碰撞池线性加速（LINAC）碰撞池。在LINAC中，通过插入具有DC梯度的T电极向碰撞室施加小的轴向电场。这将最大限度地减少在LINAC中的停留时间并提高总体传输效率。 我们去掉了几个不必要的四极杆，从而缩短了整个仪器。这将提高整体传输效率。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We describe a prototype tandem mass spectrometer that is designed to increase the efficiency of linked-scan analyses by >100-fold over conventional linked-scan instruments. The key element of the mass spectrometer is a novel high ion capacity ion trap, combined in tandem configuration with a quadrupole collision cell and a quadrupole mass analyzer (i.e. a TrapqQ configuration). This ion trap can store >106 ions without significant degradation of its performance. The current mass resolution of the trap is 100450 full width at half maximum for ions in the range 8004000 m/z, yielding a 1020 m/z selection window for ions ejected at any given time into the collision cell. The sensitivity of the mass spectrometer for detecting peptides is in the low femtomole range. We can envisage relatively straightforward modifications to the instrument that should improve both its resolution and sensitivity. We tested the tandem mass spectrometer for collecting precursor ion spectra of all the ions stored in the trap and demonstrated that we can selectively detect a phosphopeptide in a mixture of non-phosphorylated peptides. Based on this prototype instrument, we plan to construct a fully functional model of the mass spectrometer for detecting modification sites on proteins and profiling their abundances with high speed and sensitivity. Currently we are testing a second generation instrument coupled to an orthogonal time-of-flight analyzer for accurate mass readout of both the parent and fragment ions. Towards this goal we have: We have optimized the high capacity ion trap and the adjacent collision cell by incorporating a cylinder housing to use different gases. This will give us control over pressure in each region and allow us to use different gases in each region for better ion cooling. We changed our original quadrupole collision cell to a linearly accelerating (LINAC) collision cell. In the LINAC a small axial electric field is applied to the collision cell by inserting a T electrode with a DC gradient. This will minimize the residence time in LINAC and increase overall transmission efficiency. We shortened the entire instrument by removing several unnecessary quadrupoles. This will increase the overall transmission efficiency.