Huntley Adam P, Hollerbach Adam L, Norheim Randolph V, Hamid Ahmed M, Anderson Gordon A, Garimella Sandilya V B, Ibrahim Yehia M
Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, United States.
Gordon A. Anderson Custom Electronics (GAACE), Kennewick, Washington 99338, United States.
Anal Chem. 2024 Feb 9. doi: 10.1021/acs.analchem.3c05594.
Ion mobility-mass spectrometry (IMS-MS) is used to analyze complex samples and provide structural information on unknown compounds. As the complexity of samples increases, there is a need to improve the resolution of IMS-MS instruments to increase the rate of molecular identification. This work evaluated a cyclable and variable path length (and hence resolving power) multilevel Structures for Lossless Ion Manipulations (SLIM) platform to achieve a higher resolving power than what was previously possible. This new multilevel SLIM platform has eight separation levels connected by ion escalators, yielding a total path length of ∼88 m (∼11 m per level). Our new multilevel SLIM can also be operated in an "ion cycling" mode by utilizing a set of return ion escalators that transport ions from the eighth level back to the first, allowing even extendable path lengths (and higher IMS resolution). The platform has been improved to enhance ion transmission and IMS separation quality by reducing the spacing between SLIM boards. The board thickness was reduced to minimize the ions' escalator residence time. Compared to the previous generation, the new multilevel SLIM demonstrated better transmission for a set of phosphazene ions, especially for the low-mobility ions. For example, the transmission of / 2834 ions was improved by a factor of ∼3 in the new multilevel SLIM. The new multilevel SLIM achieved 49% better resolving powers for GRGDS ions in 4 levels than our previous 4-level SLIM. The collision cross-section-based resolving power of the SLIM platform was tested using a pair of reverse sequence peptides (SDGRG, GRGDS). We achieved 1100 resolving power using 88 m of path length (i.e., 8 levels) and 1400 following an additional pass through the eight levels. Further evaluation of the multilevel SLIM demonstrated enhanced separation for positively and negatively charged brain total lipid extract samples. The new multilevel SLIM enables a tunable high resolving power for a wide range of ion mobilities and improved transmission for low-mobility ions.
离子淌度-质谱联用（IMS-MS）用于分析复杂样品，并提供未知化合物的结构信息。随着样品复杂性的增加，需要提高IMS-MS仪器的分辨率以提高分子鉴定的速率。这项工作评估了一种可循环且可变路径长度（从而具有分辨能力）的无损离子操纵多级结构（SLIM）平台，以实现比以往更高的分辨能力。这种新的多级SLIM平台有八个通过离子梯连接的分离级，总路径长度约为88米（每级约11米）。我们新的多级SLIM还可以通过一组返回离子梯以“离子循环”模式运行，这些离子梯将离子从第八级传输回第一级，从而实现甚至可扩展的路径长度（以及更高的IMS分辨率）。该平台已通过减小SLIM板之间的间距得到改进，以提高离子传输和IMS分离质量。板的厚度已减小，以尽量减少离子在离子梯中的停留时间。与上一代相比，新的多级SLIM对一组磷腈离子表现出更好的传输性能，特别是对于低迁移率离子。例如，在新的多级SLIM中，/ 2834离子的传输提高了约3倍。新的多级SLIM在4级时对GRGDS离子的分辨能力比我们之前的4级SLIM提高了49%。使用一对反向序列肽（SDGRG，GRGDS）测试了基于碰撞截面的SLIM平台分辨能力。我们使用88米的路径长度（即8级）实现了1100的分辨能力，在额外通过八级后达到1400。对多级SLIM的进一步评估表明，对带正电和带负电的脑总脂质提取物样品的分离得到了增强。新的多级SLIM能够为广泛的离子迁移率提供可调谐的高分辨能力，并改善低迁移率离子的传输。
