Nanospray desorption electrospray ionization mass spectrometry, a powerful ambient sampling and imaging technique, is herein coupled as an isolated source with 21 Tesla (21T) Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS). Absorption-mode data, enabled by an external data acquisition system, is applied for improved mass resolution, accuracy, and dynamic range without compromising spectral acquisition rates. Isotopic fine structure (IFS) information is obtained from the ambient sampling of living Bacillus and Fusarium species, allowing for high confidence in molecular annotations with a resolution >830 k (at m/z 825). Tandem mass spectrometry experiments for biological samples are shown to retain the IFS in addition to gained fragmentation information, providing a further degree of annotation confidence from ambient analyses. Rat brain was imaged by nanospray desorption electrospray ionization (nano-DESI) 21T FTICR MS in ∼5 h using 768 ms transients, producing over 800 molecular annotations using the METASPACE platform and low-parts-per-billion mass accuracy at a spatial resolution of ∼25 × 180 μm. Finally, nano-DESI 21T FTICR MS imaging is demonstrated to reveal images corresponding to the IFS, as well as hundreds of additional molecular features (including demonstrated differences as low as 8.96 mDa) that are otherwise undetected by a more conventional imaging methodology.

中文翻译：

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吸收模式 21 特斯拉傅里叶变换离子回旋共振质谱法的纳喷雾解吸电喷雾电离成像和直接采样能力

纳米喷雾解吸电喷雾电离质谱是一种强大的环境采样和成像技术，在此作为隔离源与 21 特斯拉 (21T) 傅里叶变换离子回旋共振质谱 (FTICR MS) 耦合。由外部数据采集系统启用的吸收模式数据可用于提高质量分辨率、准确度和动态范围，而不会影响光谱采集速率。同位素精细结构 (IFS) 信息是从活的芽孢杆菌和镰刀菌物种的环境采样中获得的，从而以 > 830 k 的分辨率（在m/z825)。生物样品的串联质谱实验显示，除了获得的碎片信息外，还保留了 IFS，从环境分析中提供了更高程度的注释置信度。大鼠脑通过纳米喷雾解吸电喷雾电离 (nano-DESI) 21T FTICR MS 在约 5 小时内使用 768 ms 瞬变进行成像，使用 METASPACE 平台产生超过 800 个分子注释，空间分辨率为 10 亿分之几的低质量精度〜25×180微米。最后，nano-DESI 21T FTICR MS 成像被证明可以揭示与 IFS 相对应的图像，以及数百个其他分子特征（包括低至 8.96 mDa 的差异），这些特征是更传统的成像方法无法检测到的。