Electrospray ionization (ESI) is often affected by corona discharge when spraying 100% aqueous solutions as the voltage that induces discharge can be well below the onset voltage of ESI. As a result, it is especially challenging to perform native mass spectrometry in negative ion mode where 100% aqueous solution is preferred. Here we report a simple instrumentation method to improve the performance of ESI in negative ion mode based on capillary vibrating sharp-edge spray ionization. By attaching a fused silica capillary emitter to a vibrating glass slide, improved signal quality is achieved for various analytes in aqueous solutions over applying ESI alone. Compared to commercial ESI sources using nebulization gas to reduce discharge, 10-100-fold enhancement in signal intensity and 3-10-fold improvement in S/N are achieved for various kinds of molecules including DNA, peptides, proteins, and oligosaccharides. Finally, the new method demonstrates utility for native mass spectrometry analysis of proteins and G-quadruplex DNA. The present method is expected to have great potential to be adopted by the scientific community because of its improved analytical performance, simplicity, and low cost.

中文翻译：

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使用毛细管振动锐边喷雾电离轻松改进负离子模式电喷雾电离。

喷雾 100% 水溶液时，电喷雾电离 (ESI) 通常会受到电晕放电的影响，因为引起放电的电压可能远低于 ESI 的起始电压。因此，在负离子模式下进行天然质谱分析尤其具有挑战性，其中优选 100% 水溶液。在这里，我们报告了一种基于毛细管振动锐边喷雾电离的简单仪器方法，用于提高负离子模式下 ESI 的性能。通过将熔融石英毛细管发射器连接到振动载玻片上，与单独应用 ESI 相比，水溶液中各种分析物的信号质量得到了改善。与使用雾化气体减少放电的商用 ESI 源相比，包括 DNA、肽、蛋白质和寡糖在内的各种分子的信号强度提高了 10-100 倍，信噪比提高了 3-10 倍。最后，新方法展示了蛋白质和 G-四链体 DNA 的天然质谱分析的实用性。本方法由于其分析性能提高、简单且成本低廉，预计将具有被科学界采用的巨大潜力。