Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, United States.
J Am Soc Mass Spectrom. 2023 Dec 6;34(12):2849-2856. doi: 10.1021/jasms.3c00348. Epub 2023 Nov 20.
Structures for lossless ion manipulations (SLIM) technology has demonstrated high resolving power ion mobility separation and flexibility to integrate complex ion manipulations into a single experimental platform. To enable IMS separations, trapping/accumulating ions inside SLIM (or in-SLIM) prior to injection of a packet for separations provides ease of operation and reduces the need for dedicated ion traps external to SLIM. To fully characterize the ion accumulation process, we have evaluated the effect of TW amplitudes, ion collection times, and storage times on the "in-SLIM" accumulation process. The study utilized a SLIM module comprising 5 distinct tracks, each with a specific ion accumulation configuration. The effect of the TW conditions on the accumulation process was investigated for a 3-peptide mixture: kemptide, angiotensin II, and neurotensin at a TW speed of 106 m/s. The effect of ion accumulation time/collection time and storage time was investigated, in addition to TW amplitude. Overall, the signal of the analyte ions increased when the ion collection time increased from 49 to 163 ms but decreased when the ion collection time increased further to 652 ms due to the space charge effects. Ion losses were observed at high TW amplitudes (e.g., 15 V and 20 V). In addition, under space charge conditions (e.g., collection times of 163 and 652 ms), the signal of the analyte ions decreased with an increase in storage times for all TW amplitudes applied to the trapping region. For ion accumulation, the data indicate that gentler TW conditions must be utilized to minimize ion losses and fragments to benefit from the "in-SLIM" accumulation process. Wider SLIM tracks provided better performance than those with narrower tracks.
用于无损离子操控（SLIM）技术的结构已经展示了高分辨率的离子迁移率分离能力，并且具有将复杂的离子操控集成到单个实验平台中的灵活性。为了实现 IMS 分离，在注入分离用的包络之前，在 SLIM 内部（或在 SLIM 中）对离子进行捕获/积累，这提供了易于操作的优势，并减少了对 SLIM 外部专用离子阱的需求。为了充分表征离子积累过程，我们评估了 TW 幅度、离子收集时间和存储时间对“在 SLIM 内”积累过程的影响。该研究利用了由 5 个不同轨道组成的 SLIM 模块，每个轨道都具有特定的离子积累配置。在 TW 速度为 106 m/s 的情况下，研究了 TW 条件对包含 3 种肽混合物（kemptide、血管紧张素 II 和神经降压素）的积累过程的影响。除了 TW 幅度之外，还研究了离子积累时间/收集时间和存储时间的影响。总体而言，随着离子收集时间从 49 增加到 163 ms，分析物离子的信号增加，但当离子收集时间进一步增加到 652 ms 时，由于空间电荷效应，信号减小。在高 TW 幅度（例如 15 V 和 20 V）下观察到离子损失。此外，在空间电荷条件下（例如，收集时间为 163 和 652 ms），随着施加到捕获区域的所有 TW 幅度的存储时间的增加，分析物离子的信号减小。对于离子积累，数据表明，必须使用更温和的 TW 条件来最小化离子损失和碎片，以受益于“在 SLIM 内”积累过程。较宽的 SLIM 轨道比较窄的轨道提供更好的性能。
