Department of Chemistry, National Tsing Hua University 101, Section 2, Kuang-Fu Rd, Hsinchu 300044, Taiwan.
Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University 101, Section 2, Kuang-Fu Rd, Hsinchu 300044, Taiwan.
J Am Soc Mass Spectrom. 2022 Oct 5;33(10):1883-1890. doi: 10.1021/jasms.2c00179. Epub 2022 Aug 30.
Electrospray ionization (ESI) mass spectrometry (MS) is one of the key techniques used in biomolecular analysis nowadays. It relies on formation of polydisperse microdroplets, which undergo desolvation and liberate ions to the gas phase. Here we demonstrate low-frequency-sound-modulated ESI for analysis of biomolecules. By using a low-frequency (50-350 Hz) sound, it is possible to deflect electrospray microdroplets toward the mass spectrometer's orifice. Microdroplets of different sizes are deflected to a different extent leading to a partial size segregation. This effect leads to either an increase or decrease of MS signal intensity as well as signal-to-noise ratio. It also affects the selectivity of the ESI-MS analysis. The observations are rationalized by taking into account different pathways of ion formation and the likelihood of deflecting microdroplets of certain size. The online ESI-MS observations are supported with offline shadowgraphs obtained at varied sound frequencies, signal amplitudes, and phase shifts.
电喷雾电离（ESI）质谱（MS）是当今生物分子分析中使用的关键技术之一。它依赖于多分散微液滴的形成，这些微液滴经历去溶剂化并将离子释放到气相中。在这里，我们展示了低频声波调制的 ESI 用于生物分子分析。通过使用低频（50-350 Hz）声波，可以将电喷雾微液滴引导到质谱仪的喷口。不同大小的微液滴被引导到不同的程度，导致部分尺寸分离。这种效应导致 MS 信号强度和信噪比的增加或减少。它还影响 ESI-MS 分析的选择性。通过考虑不同的离子形成途径以及一定尺寸的微液滴的偏转可能性，可以对观察结果进行合理化解释。在线 ESI-MS 观察结果得到了离线阴影图的支持，这些阴影图是在不同的声频、信号幅度和相移下获得的。
