Film sample introduction sample enriching apparatus in on-line gas analysis mass spectrogram

Abstract

The invention discloses a film sample introduction enriching device in an online gas analysis mass spectrometer, the film sample introduction enriching device comprises a film, a vacuum difference cavity body, a circulation pump, a fine tuning vacuum control valve, a tubule, a capillary, a sample inlet tube, a sample feeding valve, a sample feeding cavity, an end cover, a mechanical pump and a difference extraction opening. The film sample introduction enriching device has the advantages of good mobility, being capable of rapidly enriching samples of organic contaminants in air, realizing direct sample introduction and online enriching of samples, shortening sample responding time, dynamic balance status of the vacuum of the vacuum difference cavity body and constant degree of vacuum in the mass spectrometer during the analysis process, which is helpful to quantitative analysis, effectively reduces the adsorption and memory effect of the samples at the film surface and prolongs the service life of the film, and the enriching efficiency of the film sample introduction system can be controlled according to the test requirements.

Description

technical field [0001] The invention relates to a mass spectrometer, and in particular provides a novel membrane sample enrichment device for online gas analysis mass spectrometry. 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, online monitoring of organic pollutants has been widely concerned. The method for measuring organic matter recommended by the U.S. Environmental Protection Agency (method for measuring organic matter in water: EPA601~612, method for measuring toxic organic matter in ambient air: T0-1~T0-17) sample pretreatment process is time-consuming and costly, and cannot meet the current requirements. The need for continuous monitoring of the air, and the lengthy offline analysis process may change some components of the sample, affecting the accuracy of the analysis results. Therefore, the development of rapid and r...

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Problems solved by technology

[0004] However, the traditional membrane sampling system adopts the design method that the membrane is directly close to the ionization region. This design makes the vacuum gap on both sides of the membrane large, and the pressure on both sides of the membrane is large, so the gas permeates through the membrane quickly, so it is necessary to use a lot of Only a small-area membrane can ensure the vacuum requirements in the mass spectrometer. The membrane area is small and thin (in order to ensure the sample response time, a membrane with a thickness of less than 200 μm is required). On the one hand, it brings great inconvenience to the installation. The most important The problem is that the small area of ​​the membrane leads to a small contact area between the sample and the membrane, which reduces the enrichment efficiency of the membrane.

[0005] The response time and sample signal fall time of similar products on the market are too long, which still has certain shortcomings for demanding online experiments

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