Physics Department, Brown University, Providence, RI, USA.
School of Engineering, Brown University, Providence, RI, USA.
Nat Commun. 2024 Sep 4;15(1):7709. doi: 10.1038/s41467-024-51455-x.
Electrospray ionization is widely used to generate vapor phase ions for analysis by mass spectrometry in proteomics research. However, only a small fraction of the analyte enters the mass spectrometer due to losses that are fundamentally linked to the use of a background gas to stimulate the generation of ions from electrosprayed droplets. Here we report a nanopore ion source that delivers ions directly into high vacuum from aqueous solutions. The ion source comprises a pulled quartz pipette with a sub-100 nm opening. Ions escape an electrified meniscus by ion evaporation and travel along collisionless trajectories to the ion detector. We measure mass spectra of 16 different amino acid ions, post-translationally modified variants of glutathione, and the peptide angiotensin II, showing that these analytes can be emitted as desolvated ions. The emitted current is composed of ions rather than charged droplets, and more than 90% of the current can be recovered in a distant collector.
电喷雾电离广泛应用于蛋白质组学研究中，通过质谱分析生成气相离子。然而，由于与使用背景气体从电喷雾液滴中激发离子基本相关的损失，只有一小部分分析物进入质谱仪。在这里，我们报告了一种纳米孔离子源，它可以将离子直接从水溶液输送到高真空环境中。该离子源由一个带有亚 100nm 开口的拉制石英管组成。离子通过离子蒸发逃离带电的弯月面，并沿着无碰撞轨迹行进到离子探测器。我们测量了 16 种不同的氨基酸离子、谷胱甘肽的翻译后修饰变体和肽血管紧张素 II 的质谱，表明这些分析物可以作为去溶剂化离子发射。发射电流由离子而不是带电液滴组成，并且在远处的收集器中可以回收超过 90%的电流。
