The performance of a compact high‐pressure electrospray ionization (HP‐ESI) source that can be readily used for commercial atmospheric pressure ionization (API) mass spectrometers is reported. The ion source employs a converging–diverging outlet nozzle, and ions/droplets generated inside the high‐pressure compartment are carried by the high‐velocity air jet toward the mass spectrometry (MS) ion inlet placed under the atmospheric pressure. With the use of a shielding electrode, the HP‐ESI can also be operated with its emitter held at ground potential. This feature prevents the flow of current from the emitter to other electrically grounded components and facilitates the connection of ion source to liquid chromatography (LC) columns or capillary electrophoresis. Sensitive detection of proteins from highly conductive aqueous solutions such as 0.1% trifluoroacetic acid (TFA) solution and the prevention of electrochemical artifacts by the grounded emitter operation are demonstrated.

中文翻译：

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使用即插即用离子源可轻松实现高压ESI-MS及其在高导电性水溶液中的应用

据报道，紧凑型高压电喷雾电离（HP-ESI）源的性能可轻松用于商业大气压电离（API）质谱仪。离子源使用一个会聚-发散的出口喷嘴，高压室内产生的离子/液滴被高速空气射流带到置于大气压下的质谱（MS）离子入口。通过使用屏蔽电极，HP-ESI的发射极也可以保持在接地电位。此功能可防止电流从发射极流向其他接地元件，并有助于将离子源连接到液相色谱（LC）色谱柱或毛细管电泳。灵敏地检测高导电性水溶液（例如0）中的蛋白质。