Ion gate control method for automatically enriching ions

Abstract

The invention discloses an ion gate control method for automatically enriching ions. The ion gate control method is used for improving the detection sensitivity of an ion mobility spectrometry. Duringthe opening period of the ion gate, the two groups of gate electrodes keep the same potential, and a uniform initial electric field is formed in the ion migration tube; when the ion gate is closed, the potential of one group of gate electrodes is increased, so that the potential is kept the same as that of the annular electrode adjacent to the ion gate in the ionization region, and an ion enrichment electric field which is gradually reduced in the direction from the ion source to the ion gate is formed in the ionization region; the intensity of the ion enrichment electric field is lower thanthat of the initial electric field, and the ion number density is increased in the process that ions generated by the ionization source move towards the ion gate; and when the ion gate is opened again, the initial electric field is recovered in the ionization region, and the ion current density of the enriched ions in front of the ion gate is enhanced, so that a stronger ion spectrum peak signal is obtained at the effective opening time of the same ion gate. According to the method, the ion migration tube does not need to be specially modified, and the method is simple and high in universality.

Description

technical field [0001] The invention relates to a control method of a Bradbury-Nielsen type ion gate in an ion mobility spectrometer, in particular to an ion gate control method for automatically enriching ions in an ionization region. Background technique [0002] Ion Mobility Spectrometry (IMS) is a pulsed ion cluster separation and detection technique similar to time-of-flight mass spectrometry. The ion number density and ion current density of ion clusters injected into the ion mobility region directly determine the sensitivity of ion mobility spectrometry detection. [0003] In order to achieve ion enrichment under atmospheric pressure, Li Haiyang et al. (CN1544931A) in 2004 and Li Yuanjing et al. (CN101470100B) in 2007 respectively proposed methods for ion trapping enrichment using field-free regions. However, according to the electric field tendency of ions under atmospheric pressure, ions cannot stay and be enriched in the field-free region, and the above method is ...

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Problems solved by technology

However, the structure of the ion transfer tube is relatively complex, and its universality is poor.

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