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

该子项目是利用 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来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 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，我们正在制作第二代仪器，其改进将允许其耦合到正交飞行时间分析仪，用于精确读出母离子和碎片离子的质量。

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 making a second generation instrument with improvements that will allow its coupling to an orthogonal time-of-flight analyzer for accurate mass readout of both the parent and fragment ions.