Composite ionization source based on vacuum ultraviolet light ionization and atmospheric pressure ionization

Abstract

The invention relates to mass spectrometry instrument, and particularly to a composite ionization source based on vacuum ultraviolet light ionization and atmospheric pressure ionization. The composite ionization source based on vacuum ultraviolet light ionization and atmospheric pressure ionization comprises a vacuum ultraviolet light source, an ionization chamber cavity, an ion funnel and an atmospheric pressure ionization source; a sample gas capillary tube connector, a vacuum gauge connector and a mechanical vacuum pump extraction opening are formed in the wall of the ionization chamber cavity. A direct voltage and a radio-frequency voltage are applied to the ion funnel, so that ions which are not in the axis can be focused on the axis, and the ions are transferred into a mass analyzer below the ion funnel to be analyzed. According to the composite ionization source based on vacuum ultraviolet light ionization and atmospheric pressure ionization, the vacuum ultraviolet light source can ionize polar molecules and nonpolar molecules, the atmospheric pressure ionization source can ionize compounds with the ionization energy higher than the photon energy of vacuum ultraviolet light, and the range of ionizable compounds is widened; in addition, after sample molecules which are not ionized in the atmospheric pressure ionization source enter the ionization chamber cavity, secondary ionization can be conducted on the sample molecules through the vacuum ultraviolet light, and the ionization efficiency and the detection sensitivity are improved.

Description

technical field [0001] The invention relates to a mass spectrometer, in particular to a composite ionization source based on vacuum ultraviolet photoionization and atmospheric pressure ionization. In the composite ionization source designed by the present invention, the vacuum ultraviolet photoionization can ionize polar and non-polar molecules, and the atmospheric pressure ionization source can ionize compounds whose ionization energy is higher than the vacuum ultraviolet photon energy, which broadens the scope of ionizable compounds; and, The sample molecules that have not been ionized in the atmospheric pressure ionization source can be ionized twice by vacuum ultraviolet light after entering the cavity of the ionization chamber, which improves the ionization efficiency and detection sensitivity. Background technique [0002] In recent years, a variety of atmospheric pressure ionization sources have been developed, such as low temperature plasma ionization source (LTP), e...

AI Technical Summary

Problems solved by technology

However, the light window material used in the vacuum ultraviolet light source limits the photon energy of the transmitted light

At present, LiF optical window materials have the highest photon energy of 11.8eV, which can effectively ionize compounds with ionization energy lower than 11.8eV, but can't do anything for compounds with ionization energy higher than 11.8eV.

Moreover, the optical density of commercial vacuum ultraviolet lamps is limited, which limits the ionization efficiency of vacuum ultraviolet photoionization to a certain extent.

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