Hollow cathode discharge vacuum ultraviolet light ionization source inside minitype mass spectrograph

Abstract

The invention discloses a hollow cathode discharge vacuum ultraviolet light ionization source inside a minitype mass spectrograph. Ions obtained through ionizing by taking a cylindrical electrode as a hollow discharge cathode and a circular metal electrode as a discharge electrode in an ionization chamber are directly introduced into the minitype mass spectrograph through an ion funnel; an inert gas is filled into a discharge area, the discharge area is kept between 50 Pa and 200 Pa, and the tail end of the discharge area of a hollow cathode and the tail end of the hollow cathode effectively transmit vacuum ultraviolet light by using magnesium fluoride glass; an ion funnel area is directly connected with a discharge luminous area, a sample enters from the rear end of the discharge area and is ionized in the ion funnel area, and ions obtained though ionization are directly compressed into the minitype mass spectrograph through the ion funnel. Ultraviolet light beams with large light spots, which are generated through hollow cathode discharge, can ionize the sample within a large range, the ion funnel can realize the beam contraction and the focusing of the ions in a space, and the ultraviolet light beams and the ion funnel are combined so as to effectively enhance photon utilization ratio and instrumental sensitivity.

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 technology is expected to further improve the sensitivity of mass spectrometry on-line analysis. Background technique [0002] Traditional organic mass spectrometry analysis generally uses an electron bombardment ionization source, which produces a large number of fragment ions, and the spectrum is complex and difficult to distinguish. It is a laboratory analysis method. The amount of environmental samples is large, and fast online detection technology is required. Vacuum ultraviolet light is a very effective soft ionization method, and its photon energy is 8-11eV. More than 99.99% of components (N 2 , O 2 、H 2 O.CO 2 etc.) to generate signal interference. The energy of the photon just exceeds the critical ionization energy of the sample molecule, there is no excess energy ...

AI Technical Summary

Problems solved by technology

The research group of Professor Zimmermann of the German National Center for Environmental and Health Research has developed a pulsed electron bombardment vacuum ultraviolet photoionization source, which uses electron resonance to excite multiple photons to enhance the density of photons, and the number of photons can reach 2.6×10 18 photons / s, the detection limit reaches 20ppb without enrichment, but this method is complicated and costly

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