A Control System for a Four-Sector Tandem Mass Spectrometer

我们开发了一种新的采集处理器单元，可以同时控制四扇区串联质谱仪的MS1和MS2，从而可以在一次测量中从多个前体离子中获取MS/MS光谱。现有的四扇区串联质谱仪（MS1需要手动切换质量到每个前体离子的中心，导致时间和样品损失）的操作困难可以通过将其连接到上述控制系统来克服。在目前的系统中，为了将磁场精确地切换到MS1中前体离子的中心，可以通过使用适当的校准剂插值每个选定的质量来重新校准，从而正确地补偿磁场。在MS1中自动选择的每个前体离子都可以在碰撞池中通过氦轰击独立地分解，并且由每个前体离子产生的碎片离子可以很容易地在MS2中分析。在此过程中，系统工程工作站（蛋白质研究所JMS-HX221CP中的数据采集系统）可以同步控制MSI和MS2的磁场和电场的四组数字模拟转换器（DAC）。采用四扇形串联质谱仪（JMS-HX221CP）对多肽和蛋白质进行一级结构分析。多前体离子控制的质谱分析方法在多肽和蛋白质的测序中是有效和快速的。此外，结合使用稳定同位素标记、多肽方法和现有的串联质谱计，可以轻松可靠地确定多肽和蛋白质的氨基酸序列。

We have developed a new acquisition processor unit simultaneously to control MS1 and MS2 of a four-sector tandem mass spectrometer that makes it possible to acquire the MS/MS spectra from multi-precursor ions in a single measurement. The difficulty in operation of the present four-sector tandem mass spectrometer (MS1 needs to be manually switched mass to mass to the center of each precursor ion, resulting in time and sample loss) can be overcome by connecting it to the above control system.In the present system, to switch the magnetic field to the precise center of the precursor ions in a MS1, it can be correctly compensated by re-calibration using an appropriate calibrant interpolating each selected mass. Each precursor ion automatically selected in the MS1 can be decomposed independently by bombardment with helium in a collision cell, and resultant fragment ions derived from each precursor ion can be readily analyzed in a MS2. In this process, four sets of digital analo, converters (DAC) controlling magnetic and electric fields of both MSI and MS2 can be syiicliroiiized by system engineering work station (a data acquisition system in JMS-HX221CP, Institute for Protein Research).A four-sector tandem mass spectrometer (JMS-HX221CP) equipped with the above MS/MS control system was used for analyzing, primary structures of peptides and proteins. The CPUcontrolled MS/MS of multi-precursor ions was found to be effective and rapid in peptide and protein sequencing. F Urthermore, a combined use of a stable-isotope labeling, method of peptides and the present tandem mass spectrometer allowed easily and reliably to determine amino acid sequences of peptides and proteins.