Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States.
Bruker Daltonics GmbH & Co. KG, Bremen 28359, Germany.
J Am Soc Mass Spectrom. 2023 Aug 2;34(8):1798-1804. doi: 10.1021/jasms.3c00199. Epub 2023 Jul 18.
Untargeted separation of isomeric and isobaric species in mass spectrometry imaging (MSI) is challenging. The combination of ion mobility spectrometry (IMS) with MSI has emerged as an effective strategy for differentiating isomeric and isobaric species, which substantially enhances the molecular coverage and specificity of MSI experiments. In this study, we have implemented nanospray desorption electrospray ionization (nano-DESI) MSI on a trapped ion mobility spectrometry (TIMS) mass spectrometer. A new nano-DESI source was constructed, and a specially designed inlet extension was fabricated to accommodate the new source. The nano-DESI-TIMS-MSI platform was evaluated by imaging mouse brain tissue sections. We achieved high ion mobility resolution by utilizing three narrow mobility scan windows that covered the majority of the lipid molecules. Notably, the mobility resolution reaching up to 300 in this study is much higher than the resolution obtained in our previous study using drift tube IMS. High-resolution TIMS successfully separated lipid isomers and isobars, revealing their distinct localizations in tissue samples. Our results further demonstrate the power of high-mobility-resolution IMS for unraveling the complexity of biomolecular mixtures analyzed in MSI experiments.
在质谱成像（MSI）中，非靶向分离异构体和等质异位体具有挑战性。将离子淌度谱（IMS）与 MSI 相结合已成为区分异构体和等质异位体的有效策略，这极大地提高了 MSI 实验的分子覆盖度和特异性。在这项研究中，我们在俘获离子淌度谱（TIMS）质谱仪上实施了纳喷雾解吸电喷雾电离（nano-DESI）MSI。构建了一个新的 nano-DESI 源，并制造了一个特殊设计的入口延伸部分，以适应新的源。通过对小鼠脑组织切片进行成像，评估了 nano-DESI-TIMS-MSI 平台。我们利用三个覆盖大多数脂质分子的狭窄淌度扫描窗口实现了高离子淌度分辨率。值得注意的是，本研究中达到的高达 300 的淌度分辨率远高于我们之前使用漂移管 IMS 获得的分辨率。高分辨率 TIMS 成功分离了脂质异构体和等质异位体，揭示了它们在组织样本中的不同定位。我们的结果进一步证明了高淌度分辨率 IMS 用于揭示 MSI 实验中分析的生物分子混合物复杂性的强大功能。
