Monolithic integration of tandem-FAIMS based on overlapping ion peak separation and weak ion peak discovery for gas detection

High-field asymmetric ion mobility spectroscopy (FAIMS) distinguishes and separates gas-phase ions according to the nonlinear change in ion mobility in a high electric field. However, since the electric field strength cannot be increased infinitely, multiple ion peaks may overlap in a complex sample detection, which can increase the difficulty of identifying ions. This paper designed a chip called tandem-FAIMS and proposed a method to separate ions in a complex sample. The tandem-FAIMS can separate overlapping ion peaks through two-stage dispersion electrodes and draw the corresponding spectrum, which we call the fingerprint. Combining fingerprint and multipeak fitting can lead to higher detection sensitivity. In this paper, benzene, styrene, and their mixture are used as samples to evaluate the effectiveness of the proposed method. The experimental results show that there are overlapping ion peaks in the spectrum under low dispersion voltage (DV=480V,550V), and the proposed method can accurately separate the overlapping ion peaks and obtain ion peak position information. The peak position error is within ±0.5V. •Designed and manufactured a new FAIMS analysis tube.•A new method is proposed for analyzing FAIMS spectra, which can separate overlapping ion peaks and find weak ion peaks.•The proposed method is suitable for gas detection in complex environments.