Merenbloom Samuel I, Bohrer Brian C, Koeniger Stormy L, Clemmer David E
Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA.
Anal Chem. 2007 Jan 15;79(2):515-22. doi: 10.1021/ac061567m.
Two-dimensional ion mobility spectrometry (IMS-IMS) coupled with mass spectrometry is examined as a means of separating mixtures of tryptic peptides (from myoglobin and hemoglobin). In this study, we utilize two distinct drift regions that are identical in that each contains He buffer gas at 300 K. The two-dimensional advantage is realized by changing the structures of the ions. As ions arrive at the end of the first drift region, those of a specified mobility are selected, exposed to energizing collisions, and then introduced into a second drift region. Upon collisional activation, some ions undergo structural transitions, leading to substantial changes in their mobilities; others undergo only slight (or no) mobility changes. Examination of peak positions and shapes for peptides that are separated in the first IMS dimension indicates experimental peak capacities ranging from approximately 60 to 80; the peak shapes and range of changes in mobility that are observed in the second drift region (after activation) indicate a capacity enhancement ranging from a factor of approximately 7 to 17. Thus, experimental (and theoretical) evaluation of the peak capacity of IMS-IMS operated in this fashion indicates that capacities of approximately 480 to 1360 are accessible for peptides. Molecular modeling techniques are used to simulate the range of structural changes that would be expected for tryptic peptide ions and are consistent with the experimental shifts that are observed.
二维离子迁移谱（IMS-IMS）与质谱联用被作为一种分离胰蛋白酶解肽混合物（来自肌红蛋白和血红蛋白）的方法进行了研究。在本研究中，我们使用了两个不同的漂移区，它们的相同之处在于每个漂移区都含有300K的氦缓冲气体。二维优势是通过改变离子结构来实现的。当离子到达第一个漂移区末端时，选择具有特定迁移率的离子，使其经历激发碰撞，然后引入第二个漂移区。经过碰撞激活后，一些离子会发生结构转变，导致其迁移率发生显著变化；其他离子仅发生轻微（或无）迁移率变化。对在第一维离子迁移谱中分离的肽段的峰位置和峰形状进行检查，结果表明实验峰容量范围约为60至80；在第二个漂移区（激活后）观察到的峰形状和迁移率变化范围表明容量增强了约7至17倍。因此，以这种方式操作的IMS-IMS峰容量的实验（和理论）评估表明，肽段的峰容量可达约480至1360。分子建模技术用于模拟胰蛋白酶解肽离子预期的结构变化范围，并与观察到的实验位移一致。
