Vacuumeultraviolet lamp ionization device in time-of-flight mass spectrometer

Abstract

This invention relates to one fly time mass spectrum vacuum ultraviolet isolation device, which comprises the following parts: one ionization chamber fixed with vacuum ultraviolet lamp as ion source; one ion repel electrode in one to four mm to the lamp window and earth electrode at ten to fifteen mm to the dispel electrode; ion repel electrode and earth connection electrode weak field acceleration ion electron for isolation; light exit hole with diameter as two to 8mm down the electrodes; one capillary to lead vacuum ultraviolet lamp front end with light axis vertical to gas sample in direction.

Description

technical field [0001] The invention belongs to a mass spectrometer, in particular to a miniature time-of-flight mass spectrometer for analyzing volatile organic pollutants in the air. The ionization range of VUV photoionization is further improved by using the ionization technology. Background technique [0002] Volatile organic compounds and semi-volatile organic pollutants are very low in the atmosphere, but most of them have pathogenic and carcinogenic effects. Therefore, the monitoring of organic pollutants has been widely concerned by people. Due to the time-consuming and high cost of traditional off-line analysis methods, they cannot meet the current needs of continuous monitoring of air, water and other pollution sources. Some shortcomings and limitations of off-line monitoring and analysis techniques have promoted the development of rapid, on-line and high-resolution on-site instrument detection and corresponding analysis methods in environmental monitoring. Mass s...

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Problems solved by technology

[0004] An important factor that hinders the wider application of VUV is the relatively small number of photons generated by the vacuum ultraviolet lamp per unit time (10 10 photon / s), so the use of vacuum ultraviolet lamp ionization to achieve high-sensitivity detection must be combined with separation or enrichment techniques, such as chromatographic pre-separation, membrane sample enrichment, ion trap ion enrichment, etc. For this, Mulhlberger et al. used electronic resonance excitation Multi-photon, enhanced photon density, the number of photons can reach 2.6×10 18 photon / s, the detection limit reaches 10ppm without enrichment, but this method is complicated and costly

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