Flexing the electrified meniscus: The birth of a jet in electrosprays
Flexing the electrified meniscus: The birth of a jet in electrosprays
复制标题
DOI：
10.1021/ac049817r
复制
发表时间：
2004-07-15
影响因子：
7.4
通讯作者：
Vertes, A
中科院分区：
文献类型：
--
作者：
Marginean, I;Parvin, L;Vertes, A
通过带电弯月面喷射液体已成为从大生物分子产生离子的首选方法。使用质谱法，可以分析产生的离子，以提供有关其组成和结构的详细信息。该技术实现了高通量蛋白质分析，这是回答蛋白质组学提出的问题的先决条件。在这份报告中，泰勒锥变形的静电喷涂的机制中发挥了核心作用。已知自发喷雾电流振荡存在于大多数电喷雾状态中，并且影响引入质谱仪的离子流。泰勒锥在其整个演化过程中的快速延时成像表明其表面上存在节线和驻波。建立了锥脉动循环的四个阶段（液体积聚、锥形成、射流喷射、松弛）。基于图像分析，确定顶点速度、曲率和张开角。在射流喷射过程中，顶点速度和曲率都表现出奇异性。此外，泰勒锥变形的脉动频率确定使用光折射测量的傅立叶分析。由反电极收集的电喷雾电流的振荡频率显示出与锥体变形的密切相关性，提供了将喷雾电流振荡与泰勒锥脉动联系起来的第一个直接证据。因此，在整个喷涂过程中监测振荡频率并调节喷涂参数可用于稳定喷涂。此外，使飞行时间系统中的离子注入与自发喷雾振荡同步可以提高收集的质谱中的信噪比。
Spraying of liquids through an electrified meniscus has become a method of choice to produce ions from large biomolecules. Using mass spectrometry, the generated ions can be analyzed to provide detailed information on their composition and structure. This technique enables high-throughput protein analysis that is a prerequisite for answering the questions presented by proteomics. In this report, Taylor cone deformations are shown to play a central role in the mechanism of electrostatic spraying. Spontaneous spray current oscillations are known to exist in most electrospray regimes and affect the stream of ions introduced into the mass spectrometer. Fast time-lapse imaging of the Taylor cone throughout its evolution indicates the presence of a nodal line and standing waves on its surface. Four phases of the cone pulsation cycle (liquid accumulation, cone formation, ejection of a jet, relaxation) are established. Based on image analysis, apex velocities, curvatures, and opening angles are determined. During jet ejection, the apex velocity and the curvature exhibit singularities. Furthermore, the pulsation frequencies of the Taylor cone deformations are determined using Fourier analysis of light refraction measurements. The oscillation frequency of the electrospray current collected by the counter electrode shows close correlation to the cone deformations, providing the first direct evidence that links spray current oscillations to Taylor cone pulsation. Thus, monitoring the oscillation frequency throughout the spraying process and adjusting the spray parameters can be used to stabilize the spray. Furthermore, synchronizing the injection of ions in time-of-flight systems with the spontaneous spray oscillations may improve the signal-to-noise ratio in the collected mass spectra.