Near normal pressure photo ionization mass spectrometry device for volatile and semi-volatile compounds

Abstract

The invention provides a near normal pressure photoionization mass spectrometry device for volatile and semi-volatile compounds, which comprises a photoionization chamber, a light source and a mass spectrometer are respectively arranged at two axial ends of the photoionization chamber, and a sampling capillary tube and a dopant introduction tube are respectively arranged at one end of the photoionization chamber close to the light source along the radial direction. The dopant introduction tube is connected with a dopant introduction mechanism; and the connection position of the dopant introduction tube and the photoionization chamber is positioned on one side close to the light source relative to the connection position of the sampling capillary tube and the photoionization chamber. A sample needs to be transmitted to the high-vacuum ionization chamber, the semi-volatile sample can be directly volatilized for analysis in a near-normal-pressure state, and the problem that a capillary tube is blocked does not exist; under the near-normal-pressure condition, the sensitivity of an object to be detected can be remarkably improved through higher molecular density and ion molecule collision reaction frequency, ionization is promoted through the dopant, and the signal strength is improved.

Description

technical field [0001] The invention relates to the technical field of mass spectrometry, in particular to a near-atmospheric photoionization mass spectrometer device for volatile and semi-volatile compounds. Background technique [0002] Mass spectrometry ionizes the molecules or atoms of the sample to be tested, and then analyzes and detects the ions according to the mass-to-charge ratio (m / z). Electron impact ionization (EI) is one of the earliest and most widely used ionization sources in mass spectrometry. EI bombards the analyte molecules with hot electrons generated by an electrically heated wire (tungsten, rhenium, thorium-iridium alloy, or thorium-rhenium alloy). Since the electron energy is usually 70eV, which is much higher than the ionization energy of organic molecules, a large number of fragments will be generated in the analyte. [0003] Photoionization (PI) is a soft ionization source. Low-voltage photoionization usually uses a vacuum ultraviolet lamp (suc...

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Problems solved by technology

[0008] The technical problem to be solved by the present invention is to provide a photoionization mass spectrometry device for direct and rapid analysis of volatile and semi-volatile compounds. , and the sensitivity of the analyte can be increased by increasing the molecular density of the gas phase component to be analysed and the collision reaction of molecular ions in a near-atmospheric pressure environment

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