Research On High-Field Asymmetric Waveform Ion Mobility Spectroscopy (FAIMS) Technology

In recent years,high-field asymmetric waveform ion mobility spectrometry(FAIMS)has been widely developed for its high sensitivity,high stability,small volume,short analyzing time and so on.It has gradually become one of the most promising analytical detection technologies in the fields of proteomics,metabolomics and environmental safety monitoring.FAIMS was invented by the former Soviets union and published in English for the first time in 1993.It separates ions based the nonlinear bahavior of ion mobility under relatively high electric field to realize the analysis of species and concentration.The research on FAIMS started late in China and is not mature yet.Therefore,The systematic research on the key technologies of FAIMS provides a theoretical basis for understanding and optimizing the performance parameters and principle characteristics of the ion mobility spectrometry.In the view of the above problems,The main work of this paper focuses on the following four aspects.Firstly,By comparing various ionization methods,The electrospray ionization(ESI)was selected as the ionization method,and the working principle and system construction of the ESI were elaborated.By comparing the performance characteristics of flat-plate FAIMS and cylindrical geometry FAIMS,the flat-plate migration tube was selected as the separation electrode,and the structure principle and the process of system design of flat-plate FAIMS were elaborated,The subsequent experiments were carried out based on the ESI and flat-plate FAIMS.Secondly,In order to study the host computer control of FAIMS system,the display interface of control system is designed by QT software to achieve the control of FAIMS power supply and EFC flow valve.which reduces the uncertainty of manual control and improves the control accuracy of the system.Thirdly,In order to Study the ion detection of FAIMS system,The Faraday cup was selected as the ion detection device.The ionic signal of ESI,flat-plate FAIMS,and detection stage plate were detected by experiments,which verify the working status of various parts of the FAIMS system.Finally,In order to Study the feasibility of the working principle of FAIMS,a mixture of acetonitrile,sucrose,deionized water and formic acid was used to be tested,and the self-made FAIMS system was used as the experimental platform to separate the ions in the mixed solution,and systematically studies the control factors of the FAIMS system,such as separation voltage,compensation voltage,carrier gas flow rate,ion concentration and so on.