The performance of a miniature mass spectrometer in atmospheric analysis is closely related to the design of its sampling system. In this study, a simplified vacuum electrospray ionization (VESI) source was developed based on a combination of several techniques, including the discontinuous atmospheric pressure interface, direct capillary sampling, and pneumatic-assisted electrospray. Pulsed air was used as a vital factor to facilitate the operation of electrospray ionization in the vacuum chamber. This VESI device can be used as an efficient atmospheric sampling interface when coupled with a miniature rectilinear ion trap (RIT) mass spectrometer. The developed VESI-RIT instrument enables regular ESI analysis of liquid, and its qualitative and quantitative capabilities have been characterized by using various solution samples. A limit of detection of 8 ppb could be attained for arginine in a methanol solution. In addition, extractive electrospray ionization of organic compounds can be implemented by using the same VESI device, as long as the gas analytes are injected with the pulsed auxiliary air. This methodology can extend the use of the proposed VESI technique to rapid and online analysis of gaseous and volatile samples.

中文翻译：

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开发真空电喷雾源以实现微型离子阱质谱仪的有效大气采样

微型质谱仪在大气分析中的性能与其采样系统的设计紧密相关。在这项研究中，基于多种技术的组合，开发了一种简化的真空电喷雾电离（VESI）源，包括不连续的大气压界面，直接毛细管采样和气动辅助电喷雾。脉冲空气被用作促进真空室内电喷雾电离操作的重要因素。当与微型直线离子阱（RIT）质谱仪结合使用时，此VESI设备可用作有效的大气采样接口。发达的VESI-RIT仪器可对液体进行常规ESI分析，并且通过使用各种溶液样品来表征其定性和定量功能。精氨酸在甲醇溶液中的检出限可以达到8 ppb。此外，只要使用脉冲辅助空气注入气体分析物，就可以使用相同的VESI装置实现有机化合物的萃取电喷雾电离。这种方法可以将拟议的VESI技术的使用扩展到对气态和挥发性样品的快速在线分析。