Preliminary Theoretical Study On FAIMS Drift Tube

Many research institutions in some countries have been developing highsensitive detecting methods for drugs,explosives and environmentalpollutants during last several decades because of some factors, such aschemical and biological weapons developing rapidly,terroristic attack oncivilian construction and innocent people, dealing and smuggling drugsbecoming more and more rampant, environment pollution getting increasinglysevere, etc. FAIMS has been developed quickly and widely used in drug,explosive and environmental pollutants detecting for its simpleness,small volume, light weight, low power, high sensitivity,short analyzingtime and so on.In this thesis, the radical structure of FAIMS is described,especiallythe configuration and fabrication of core component, which is called drifttube, is depicted in detail. Also,the mathematical model of system isestablished, which gives much valuable information to the later researchers.At the same time, it is tersely described the ion molecule reactions inthe drift tube and the interactions between ion and neutral gas moleculesduring drift process. The change which of the ambient atmosphere pressureand temperature can result in the excursion of the spectrum in practicalapplication of the FAIMS is analyzed.The resolution of FAIMS is also discussed in this thesis.The mainfactors determining FAIMS resolution include gas velocity, dimension ofdrift tube and parameters of asymmetric waveform voltage. The relationbetween resolution and the factors is analyzed through theoretical study.It is in good agreement with experimental data.