Department of Chemistry, Washington State University, Pullman, WA 99164, USA.
Proteomics. 2012 Oct;12(19-20):3020-9. doi: 10.1002/pmic.201270136. Epub 2012 Aug 29.
The proof of principle for high-resolution TOF mass analysis spanning the entire range of intact singly charged proteins has recently been demonstrated. The centers of the isotope distributions of individual proteins in a complex distribution can be defined to within 0.5 Da or better up to 200 kDa with internal calibration. This achievement will have an enormous effect on the process of routine protein analysis over the next few years as the technology mainstreams. The greatest obstacle to high-resolution in the ultra-high mass range (m/z > 20 000) is the expansion-induced kinetic energy (KE) and its spread. The solution to this problem is to trap the ions in a buffer gas so that the motion of the ions can be completely defined by the applied fields. If this can accomplished without mass dependence, then any ion, regardless of size, can be mass analyzed with high resolution. This article discusses the methodology that we used to capture atmosphere sampled singly charged proteins in vacuum at a point just before they enter the mass analyzer to completely eliminate the expansion-induced KE. We then used digitally created quadrupole waveforms to inject the ions into the mass analyzer in a well-collimated plug with a controlled amount of KE. Trapping the ions to remove the expansion-induced KE and then electrodynamically manipulating the ions are the key steps to high-resolution mass analysis at any value of m/z. The impact of this technology will be discussed.
最近已经证明了用于分析整个单电荷完整蛋白质范围的高分辨率飞行时间（TOF）质谱的原理。在内部校准的情况下，通过复杂分布中的单个蛋白质的同位素分布的中心可以定义为 0.5 Da 或更好，最高可达 200 kDa。随着这项技术的主流化，在接下来的几年中，该技术将对常规蛋白质分析过程产生巨大影响。在超高质量范围（m/z > 20,000）中实现高分辨率的最大障碍是扩展引起的动能（KE）及其扩展。解决此问题的方法是将离子困在缓冲气体中，以使离子的运动完全由施加的场定义。如果可以在不依赖质量的情况下完成此操作，则可以用高分辨率对任何大小的离子进行质量分析。本文讨论了我们在将大气采样的单电荷蛋白质在进入质量分析仪之前的点在真空中捕获的方法，以完全消除扩展引起的 KE。然后，我们使用数字创建的四极波形成像将离子注入质量分析仪中，形成具有受控 KE 的准直射流。将离子捕获以去除扩展引起的 KE，然后电动力学地操纵离子是在任何 m/z 值下进行高分辨率质量分析的关键步骤。将讨论这项技术的影响。
