Electrospray Generated from the Tip-Sealed Fine Glass Capillary Inserted with an Acupuncture Needle Electrode
Electrospray Generated from the Tip-Sealed Fine Glass Capillary Inserted with an Acupuncture Needle Electrode
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DOI：
10.1007/s13361-018-2062-3
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发表时间：
2018-09
影响因子：
3.2
通讯作者：
D. Usmanov;S. Ninomiya;K. Hiraoka;H. Wada;H. Nakano;M. Matsumura;S. Sanada‐Morimura;H. Nonami
中科院分区：
文献类型：
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作者：
D. Usmanov;S. Ninomiya;K. Hiraoka;H. Wada;H. Nakano;M. Matsumura;S. Sanada‐Morimura;H. Nonami
在电喷雾中，由于发生电化学反应，多余的电荷被提供给样品溶液。最近报道了不同形式的电喷雾，如介质阻挡电喷雾电离、感应解吸电喷雾电离和介质极化驱动静电喷雾电离，其中样品溶液不直接与金属电极接触，而是被介质材料分开。本工作的目的是阐明介质阻挡电喷雾的机理。用密封的硼硅酸盐玻璃毛细管插入针灸细针作为探头。在玻璃毛细管尖端捕获样品溶液(约400nL)，并向内金属电极施加正高压(HV)脉冲(+ 4.5nV)。从μS到S，测量了随着高压脉冲宽度的变化而变化的质谱图。开始检测到的离子的脉冲宽度为~0.5ms。离子强度随时间缓慢增加，并在几秒钟内达到平台期。细胞色素c[M + NH]n+的电荷分布从几毫秒到几秒向较高的n值移动。除了锥形喷射模式的普通电喷雾，直到所有液体样品从玻璃尖端耗尽，在高压应用的早期阶段，还观察到了极化诱导电喷雾电离。
In electrospray, excess charges are supplied to a sample solution by the occurrence of electrochemical reactions. Recently, different versions of electrospray, e.g., dielectric barrier electrospray ionization, inductive desorption electrospray ionization, and electrostatic-ionization driven by dielectric polarization, have been reported in which the sample solution was not in direct contact with the metal electrode but separated by dielectric materials. The objective of the current work is to elucidate the mechanism of dielectric barrier electrospray. A sealed borosilicate glass capillary inserted with a fine acupuncture needle was used as a probe. A sample solution (~ 400 nL) was captured on the glass capillary tip and a positive high voltage (HV) pulse (+ 4.5 kV) was applied to the internal metal electrode. Mass spectra were measured as a function of the HV pulse width from μs to 10 s. Ions started to be detected with the pulse width of ~ 5 ms. The ion intensities increased slowly with time and reached a plateau in a few seconds. The charge distribution of cytochrome c [M + nH]n+shifted to higher n values from a few ms to seconds. In addition to cone-jet mode normal electrospray that lasted until all the liquid sample was depleted from the glass tip, the polarization-induced electrospray ionization was observed at the early stage of the HV application.