An Ion Gate Control Method for Automatically Enriching Ions

Abstract

The invention discloses an ion gate control method for automatically enriching ions, which realizes the improvement of the detection sensitivity of the ion mobility spectrum. During the opening of the ion gate, the two groups of gate electrodes maintain the same potential to form a uniform initial electric field in the ion transfer tube; during the closing period of the ion gate, the potential of one of the gate electrodes is raised to make it close to the ion gate in the ionization region. The ring electrode maintains the same potential, forming an ion-enriching electric field that gradually decreases along the direction from the ion source to the ion gate in the ionization region; the intensity of the ion-enriching electric field is lower than that of the initial electric field, and the ions generated by the ionization source move toward the ion gate. During the process, the ion number density increases; when the ion gate is opened again, the initial electric field is restored in the ionization region, and the ion current density of the enriched ions in front of the ion gate is enhanced, so that stronger ions can be obtained under the same effective opening time of the ion gate. peak signal. The invention does not require special modification of the ion transfer tube, and the method is simple and universal.

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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