Device for enrichment of minitype flight time mass spectrum sample on-line

Abstract

The invention discloses a membrane sampling device for direct sampling and online enrichment of sample in micro mass spectrum. The device, which adopts nonporous compact dimethyl silicone polymer lamellar membrane, can effectively limit the quantity of gas entering into mass spectrum and can also be used as the intermediate interface between the mass spectrum and the atmosphere. The inside of the device adopts a single-layer ultrathin membrane to complete quick enrichment of sample; moreover, a vacuum difference cavity is arranged behind the membrane and is used to carry out the buffering and storage of enrichment sample; because the cavity is under low vacuum condition, the area of the membrane can be enlarged to enlarge the contact area between the sample and the membrane, thereby increasing enrichment efficiency; a difference port is provided with an electromagnetic valve, therefore, a gas extraction port can be closed off before gas enrichment and gas can enter into a buffering cavity through the membrane for enrichment; after sample analysis is finished, the electromagnetic valve is opened to carry out difference gas extraction, thereby enriched sample is extracted quickly to prevent memory effect.

Description

technical field [0001] The invention belongs to a mass spectrometer, and in particular relates to a sample enrichment device for a miniature time-of-flight mass spectrometer for on-line analysis of volatile organic pollutants in the air. Background technique [0002] The content of volatile organic compounds and semi-volatile organic pollutants in the atmosphere is very low, but most of them have pathogenic and carcinogenic effects, so the monitoring of organic pollutants has been widely concerned. The main steps in the method for measuring organic matter recommended by the U.S. Environmental Protection Agency (measurement method for organic matter in water: EPA601~612, method for measuring toxic organic matter in ambient air: TO-1~TO-17) are: sample collection → pretreatment and enrichment → GC / HPLC → mass spectrometry. Although this method is very accurate, the chromatographic analysis process (a few minutes to more than 10 minutes) is time-consuming and costly, and canno...

AI Technical Summary

Problems solved by technology

However, none of these sampling methods can achieve the enrichment of the sample, which often cannot detect the mass spectrometry signal of the organic pollutant molecules with a concentration of ppb in the air.

The membrane sampling used in the literature realizes the function of direct sampling and enrichment of the sample, but the membrane sampling system adopts a design method in which the membrane is directly close to the ionization region. This

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