Comprehensive theoretical analysis and experimental exploration of ultrafast microchip-based high-field asymmetric ion mobility spectrometry (FAIMS) technique.

High-field asymmetric ion mobility spectrometry (FAIMS) has become an efficient technique for separation and characterization of gas-phase ions at ambient pressure, which utilizes the mobility differences of ions at high and low fields. Micro FAIMS devices made by micro-electromechanical system technology have small gaps of the channels, high electric field and good installation precision, as thus they have received great attentions. However, the disadvantage of relatively low resolution limits their applications in some areas. In this study, theoretical analysis and experimental exploration were carried out to overcome the disadvantage. Multiple scans, characteristic decline curves of ion transmission and pattern recognitions were proposed to improve the performance of the microchip-based FAIMS. The results showed that although micro FAIMS instruments as a standalone chemical analyzer suffer from low resolution, by using one or more of the methods proposed, they can identify chemicals precisely and provide quantitative analysis with low detection limit in some applications.