MALDI/ION TRAP MASS SPECTROMETER FOR PEPTIDE SEQUENCING

提出了一种在四极离子陷阱中捕获离子的新方法。 开发，利用编程的射频电压幅度和静电 施加到端盖电极和/或样品探头的捕获场。 此方法克服了与捕获 基质辅助激光脱附产生的高动能离子，以及 已经成功地实现了质量分辨率超过 对于1000至1500 dL的多肽，为12,000。此外， 该方法消除了通常需要高压缓冲气体的情况 用来减缓离子速度，因此，允许获得高 正常扫描速率下的分辨率质谱图。到目前为止，我们的工作是 在改进的芬尼根离子陷阱探测器(ITD)上进行，该探测器不 具有探测高质量离子或串联质量的能力 光谱分析。因此，我们建议进一步修改现行的创新及科技发展署 真空室，探测系统和电子设备，使我们能够扩展 这种方法适用于500到4000道尔顿范围内的多肽，以及 进行串联实验，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 用于正在进行的项目中的多肽分析的及时配置 中大西洋质谱学实验室，目标是 一种结构紧凑、使用方便的常规结构测试仪的研制 多肽的分析。因此，该仪器将用于 β-淀粉样多肽的结构分析 阿尔茨海默病，以确定组件上的磷酸化位点 几种疱疹病毒的蛋白，以鉴定多肽抗原 与主要组织相容性复合体(MHC)相关，并用于 其他几个合作项目。

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.