A combined linear ion trap time-of-flight system with improved performance and MSn capabilities
A combined linear ion trap time-of-flight system with improved performance and MSn capabilities
复制标题
DOI：
10.1002/rcm.440
复制
发表时间：
2001-01-01
影响因子：
2
通讯作者：
Douglas, DJ
中科院分区：
文献类型：
--
作者：
Collings, BA;Campbell, JM;Douglas, DJ
详细描述了能够进行连续质谱 (MS') 的线性离子阱飞行时间 (TOF) 质谱仪系统。自从最初描述该系统以来，已经进行了许多改进（Rapid Commun. Mass Spectrom. 1998；12:1463-1474）。阱中的压力已从 7.0 mTorr 降低至 1.8 mTorr，导致离子激发的质量分辨率从 75 增加至 240。演示了 MS3 系统的使用。 n = I 谐波的偶极子激发（而不是离子运动的 n = 0 基频）显示出具有较高的频率分辨率 f/Deltaf，但具有较低的质量分辨率 m/Deltam。实验和建模都表明，在较低压力下，离子在阱的轴向和径向方向上的碰撞冷却较少。在长达 5 秒的时间内，捕获效率接近 100%。质量分析的演示质量范围已扩展至大于 m/z 16 250。为了避免在长时间捕获蛋白质离子时形成加合物离子，需要超高真空清洁度条件，即使陷阱在 mTorr 压力范围内运行。将 TOF 升级为具有更高质量离子光学器件的反射器可将 TOF 质谱仪的质量分辨率提高到 m/z 750 时的约 5000。版权所有 (C) 2001 John Wiley & Sons, Ltd.。
A detailed description of a linear ion trap time-of-flight (TOF) mass spectrometer system, capable of sequential mass spectrometry (MS'), is given. Many improvements have been incorporated since the initial description of this system (Rapid Commun. Mass Spectrom. 1998; 12:1463-1474). The pressure in the trap has been lowered from 7.0 to 1.8 mTorr, resulting in an increase in the mass resolution of ion excitation from 75 to 240. Use of the system for MS3 is demonstrated. Dipole excitation of the n = I harmonic, instead of the n = 0 fundamental frequency of ion motion, is shown to have a higher frequency resolution, f/Deltaf, but lower mass resolution, m/Deltam. Both experiments and modeling demonstrate that at the lower pressure there is less collisional cooling of ions in the axial and radial directions of the trap. The efficiency of trapping is shown to be nearly 100% for periods up to 5 s. The demonstrated mass range for mass analysis has been extended to greater than m/z 16 250. To avoid the formation of adduct ions when trapping protein ions for extended times requires ultra-high vacuum cleanliness conditions, even though the trap operates in the mTorr-pressure range. Upgrading the TOF to a reflectron with higher quality ion optics results in an increase in the mass resolution of the TOF mass spectrometer to about 5000 at m/z 750. Copyright (C) 2001 John Wiley & Sons, Ltd.