MALDI/ION TRAP MASS SPECTROMETER FOR PEPTIDE SEQUENCING

介绍了一种在四极离子阱中捕获离子的新方法， 开发，利用程控射频电压振幅和静电 施加到端盖电极和/或样品探针的捕获场。 这种方法克服了与捕获的 通过基质辅助激光解吸产生的高动能离子，和 已经成功地实现了大规模的决议， 对于1000至1500 DL范围内的肽， 该方法避免了通常对高压缓冲气体的需要 用于延缓离子速度，因此，允许人们获得高 在正常扫描速率下的分辨率质谱。到目前为止，我们的工作已经 在改进的Finnigan离子阱检测器（ITD）上进行，其不 具有检测高质量离子或串联质量离子的能力 光谱法因此，我们建议进一步修订现行的资讯科技署 真空室，检测系统和电子设备，使我们能够扩展 这种方法可用于500至4000道尔顿范围内的肽， 进行串联实验以从所述氨基酸序列中获得氨基酸序列。 （主要）由基质辅助产生的单电荷分子离子 激光解吸我们的目的是评估这一工具， 在正在进行的项目中， 中大西洋质谱实验室，目标是 开发一种紧凑和用户友好的仪器，用于常规结构 肽的分析。因此，该仪器将用于 β-淀粉样肽的结构分析 阿尔茨海默病，以确定磷酸化位点上的大会 几种疱疹病毒的蛋白质，用于表征肽抗原 与主要组织相容性复合体（MHC）相关， 其他合作项目。

A novel method for trapping ions in a quadrupole ion trap has been developed, utilizing programmed RF-voltage amplitudes and electrostatic trapping fields applied to the end-cap electrodes and/or the sample probe. This method overcomes the difficulties associated with trapping of the high kinetic energy ions produced by matrix-assisted laser desorption, and has been successful in achieving mass resolutions greater than one part in 12,000 for peptides in the range of 1000 to 1500 DL In addition, the method obviates the need for high pressures of the buffer gas normally used to retard ion velocities and, therefore, permits one to obtain high resolution mass spectra at normal scan rates. Thus far, our work has been carried out on a modified Finnigan ion trap detector (ITD), which does not have the capabilities for detection of high mass ions or for tandem mass spectrometry. We propose, therefore, to further modify the existing ITD vacuum chamber, detection system, and electronics to enable us to extend this approach to peptides in the range of 500 to 4000 daltons, and to carry out tandem experiments to obtain amino acid sequence from the (primarily) singly-charged molecular ions produced by matrix-assisted laser desorption. It is our intention to evaluate this instrumental configuration promptly for the analysis of peptides in ongoing projects of the Middle Atlantic Mass Spectrometry laboratory, with the goal of developing a compact and user-friendly instrument for routine structural analysis of peptides. Thus, the instrument will be utilized for the structural analysis of the beta-amyloid peptides associated with Alzheimer's disease, to determine phosphorylation sites on the Assembly Protein of several herpesviruses, to characterize the peptide antigens associated with the Major Histocompatibility Complex (MHC), and for several other collaborative projects.