Study And Development Of High Performance Atmospheric Pressure Interface For Simplified Mass Spectrometry Instrumentation

Mass spectrometry is a highly sensitive and selective analytical technology for both qualitative and quantitative chemical analysis. It is used widely in analytical laboratories for academic research, industrial product development, and regulatory compliance with particular importance in proteomics, drug discovery, environmental monitoring,food regulation. Atmospheric pressure interface(API) is one of the key components in a mass spectrometry(MS) system. Instrument sensitivity, power consumption and size highly depend on the ion transfer and gas flow limiting capabilities of its API, especially for miniature MS systems. In this work, the theory of the key technologies of discontinuous atmospheric pressure interface will be explored and a pulsed pinhole discontinuous atmospheric pressure interface for simplified mass spectrometry instrument with enhanced sensitivity will be developed. This work specifically includes the following:First, an ion trap mass spectrometry prototype with a discontinuous atmospheric pressure interface(DAPI) will be developed for basis and support for the follow-up study.Second, the aerodynamic characteristics of discontinuous atmospheric pressure interface will be discussed, including the theoretical research and model building, the relationship between the geometry size and the flow conductance of the atmospheric pressure interface, etc.Third, a proof-of-concept discontinuous pinhole atmospheric pressure interface, namely PP-API, was developed and characterized for mass spectrometry instrumentation. The PP-API was analyzed and optimized theoretically with respect to gas flow rate, opening force and dimensions. A PP-API interfaced mass spectrometry system was then constructed and tested. As a discontinuous pressure interface, the PP-API allows efficient ion transfer from atmosphere pressure ionization sources to ion traps directly. Both nano-ESI and APCI ionization sources have been successfully integrated with the PP-API interface for the detection of volatile, organic, peptide and polymer samples. The use of multiple ionization sources has also been demonstrated to enhance signal intensity, as well as avoid charge competitions in ionization sources. With simplified geometry and high ion transfer efficiency, this PP-API would enable miniaturized mass spectrometry systems with high sensitivity.Forth, a miniature MS system with a pulsed pinhole discontinuous atmospheric pressure interface will be developed.In summary, this work has investigated the aerodynamic characteristics of discontinuous atmospheric pressure interface from the theory, developed a new kind of atmospheric pressure interface to improve the ion transfer efficiency and durability of the interface, expand the application range of the mass spectrometer, Improve the ion transfer efficiency and durability of the interface, expand the application range of the mass spectrometer.