Gas-phase pollutant full-species high-sensitivity online mass spectrometer and detection method

Abstract

The application discloses a kind of gas-phase pollutant full-species high-sensitivity online mass spectrometer and detection method, it is related to mass spectrometry technical development technical field.Mass spectrometer includes high-energy photoionization ion source structure, ion transmission structure and mass spectrum detection structure.High-energy photoionization ion source structure includes high-energy photon generation structure, sample introduction tube and ionization chamber, high-energy photon generation structure utilizes neon discharge to generate high-energy photon, high-energy photon is mixed with the gas to be measured that enters through sample introduction tube in ionization chamber, and the gas to be measured is ionized;Ion transmission structure is equipped with radio frequency quadrupole rod, for filtering the large amount of N2 + And O2 + Non-target background ions generated when measuring air;Mass spectrum detection structure is equipped with pulse-compensation double-electrode ion removal device, for further removing non-target background ions, relieving the measurement saturation and loss of ion detector.The application can realize the full coverage high-sensitivity detection of all gas-phase organic and inorganic pollutants in atmosphere.

Description

Technical Field

[0001] The present invention relates to the technical field of mass spectrometry technology development, and in particular to a high-sensitivity mass spectrometer and a detection method capable of detecting all organic and inorganic pollutant gases in the atmosphere. Background Art

[0002] Mass spectrometry is a method for analyzing the chemical composition of substances. It determines the molecular structure information of substances through the mass-to-charge ratio and ion abundance of ions. It can ionize and detect various substances with different ionization sources. The mass spectrometry techniques commonly used to detect gaseous substances mainly include electron ionization mass spectrometry, proton transfer reaction mass spectrometry, and single photon ionization mass spectrometry. Electron ionization usually uses an electron beam with an energy of 70eV to bombard neutral molecules to ionize them. In theory, it can ionize all organic and inorganic gases, but the high vacuum environment applicable to electron ionization technology leads to low detection sensitivity of electron ionization mass spectrometry for direct detection of gaseous species, which cannot meet the detection requirements of most low-concentration volatile organic compounds in ambient air. Proton transfer reaction mass spectrometry with higher detection sensitivity uses hydronium ions (H3O + ) undergoes a proton transfer reaction with the analyte, protonating the analyte. This ionization method can only protonate substances with a proton affinity greater than that of water and cannot detect some small hydrocarbon molecules and inorganic substances with a proton affinity less than that of water. Single-photon ionization (SPI) is a threshold ionization method. When the photon energy is equal to or greater than the ionization energy of the molecule, the molecule is directly ionized by absorbing a single photon. SPI mass spectrometry typically uses a vacuum ultraviolet lamp as a light source. The luminescence principle is to use a DC or RF electric field to excite a noble gas to produce excited atoms or excimers. The excited atoms or excimers radiate the absorbed energy as photons during a spontaneous transition to the ground state. The main luminescent gases are helium (58.4 nm), neon (74.4 nm), argon (106.7 nm), krypton (123.6 nm), and xenon (147.6 nm). To transmit the VUV light and maintain the pressure of the noble gas within the discharge chamber, the VUV lamp typically uses a magnesium fluoride window as the light outlet. After years of technological innovation, the development of high-throughput vacuum ultraviolet lamps and high-pressure ion sources has significantly improved the detection sensitivity of single-photon ionization mass spectrometry (SPIS), and it has been successfully used for online monitoring of volatile organic compounds in ambient air. However, due to the crystal structure of the window, which can only transmit light above 110 nm, traditional single-photon ionization sources generally use krypton gas discharge, generating photon energies of 10.0 eV and 10.6 eV. This cannot effectively ionize and detect organic or inorganic compounds with ionization energies exceeding 10.6 eV. Therefore, due to the limitations of the ionization method, existing mass spectrometry technologies for direct detection of gaseous substances cannot achieve full coverage and high-sensitivity detection of organic and inorganic pollutants in ambient air. Summary of the Invention

[0003] The purpose of the present invention is to provide a high-sensitivity online mass spectrometer and detection method for all species of gaseous pollutants. By combining a high-energy photoionization ion source structure, a radio frequency quadrupole and a pulse-compensated dual-electrode ion removal device, it can achieve full coverage and high-sensitivity detection of all volatile organic pollutants in the atmosphere and inorganic pollutants such as carbon dioxide, sulfur dioxide, and nitrogen oxides, broaden the applicable scope of mass spectrometry detection, and overcome the problem that existing mass spectrometry cannot take into account both full coverage and high-sensitivity detection of gaseous pollutants.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a high-sensitivity online mass spectrometer for all species of gaseous pollutants, comprising a high-energy photoionization ion source structure, an ion transmission structure and a mass spectrometry detection structure connected in sequence; the high-energy photoionization ion source structure comprises a high-energy photon generating structure, an injection tube and an ionization chamber, the high-energy photon generating structure uses neon as a discharge gas to generate high-energy photons, the high-energy photons are mixed with the gas to be measured entering through the injection tube in the ionization chamber, and the gas to be measured is ionized; the ion transmission structure comprises a radio frequency quadrupole and an electrostatic lens, one end of the radio frequency quadrupole corresponds to the outlet of the high-energy photoionization ion source structure, and the other end of the radio frequency quadrupole corresponds to the electrostatic lens, the radio frequency quadrupole is used to filter non-target background ions, and the electrostatic lens is used to focus ions; the mass spectrometry detection structure comprises a pulse extraction electrode, an acceleration electrode, a field-free flight zone, a reflection electrode, a pulse-compensation double electrode ion Removal device, microchannel plate detector and signal acquisition system, the ions entering the mass spectrometry detection structure are extracted by the pulse extraction electrode and enter the accelerating electrode for acceleration, the accelerating electrode is located at the entrance on one side of the field-free flight zone, the reflecting electrode is provided on the other side of the field-free flight zone, and an exit is also provided on one side of the field-free flight zone, the pulse-compensated dual-electrode ion removal device is arranged at the exit, the ions entering the field-free flight zone from the entrance move in the field-free flight zone, and when they move to the reflecting electrode, they are reflected and move in the opposite direction under the action of the reflecting electrode, and leave the field-free flight zone from the exit, the pulse-compensated dual-electrode ion removal device is used to further remove non-target background ions, the microchannel plate detector is used to receive ions within the specified mass range controlled by the pulse-compensated dual-electrode ion removal device, and output them to the signal acquisition system.

[0006] Preferably, the high-energy photon generating structure includes a discharge structure, a radio frequency coil, a neon gas inlet pipe and a neon gas outlet pipe, the radio frequency coil is wound around the discharge structure, the discharge structure is provided with a discharge cavity, and the neon gas inlet pipe and the neon gas outlet pipe are both connected to the discharge cavity.

[0007] Preferably, the discharge structure is made of quartz, and the gas pressure in the discharge chamber is 50-1000 Pa.

[0008] Preferably, the high-energy photoionization ion source structure further includes an arrayed microporous channel plate, which is disposed between the discharge cavity and the ionization chamber and is used to transmit high-energy photons.

[0009] Preferably, the discharge chamber, the ionization chamber, the radio frequency quadrupole and the electrostatic lens are coaxially arranged in sequence.

[0010] Preferably, the pulse-compensation dual-electrode ion removal device includes a pulse electrode and a compensation electrode, with a gap provided between the pulse electrode and the compensation electrode. The pulse electrode provides a forward electric field to allow ions to pass through within a specified pulse width time, and provides a reverse strong electric field to prevent ions from passing through during the rest of the time. The compensation electrode has a reverse stable voltage for suppressing the penetration and baseline drift of non-target background ions and secondary ions.

[0011] Preferably, the interiors of the high-energy photoionization ion source structure, the ion transport structure and the mass spectrometry detection structure are all vacuum environments.

[0012] The present invention also provides a method for detecting gaseous pollutants using the all-species high-sensitivity online mass spectrometer, comprising the following steps:

[0013] Step 1: Providing a vacuum environment for the high-energy photoionization ion source, ion transmission structure, and mass spectrometry detection structure;

[0014] Step 2: Neon gas enters the discharge chamber through the neon gas inlet pipe and flows out through the neon gas outlet pipe, maintaining a certain pressure in the discharge chamber. The radio frequency coil excites the neon gas in the discharge chamber to produce high-energy photons.

[0015] Step 3: High-energy photons pass through the arrayed microporous channel plate into the ionization chamber, mix with the gas to be tested introduced by the inlet tube, and ionize the gas to be tested;

[0016] Step 4: The ions generated by ionization enter the ion transmission structure from the outlet of the ionization chamber. Some non-target background ions are filtered by the radio frequency quadrupole and then focused by the electrostatic lens into the mass spectrometer detection structure;

[0017] Step 5: Ions entering the mass spectrometer detection structure are extracted by the positive electric field provided by the pulse extraction electrode. Then, under the action of the accelerating electrode, the ions enter the field-free flight region. After a period of uniform flight, they are repelled by the reverse electric field provided by the reflecting electrode, and the ions move in the opposite direction.

[0018] Step 6: The ions reach the pulse-compensated dual-electrode ion removal device to further remove the remaining non-target background ions;

[0019] Step 7: Ions within the specified mass range are received by the microchannel plate detector and output to the signal acquisition system.

[0020] Compared with the prior art, the present invention has achieved the following technical effects:

[0021] The high-sensitivity online mass spectrometer for all species of gaseous pollutants of the present invention can realize online detection by directly injecting samples through the sampling tube without pre-treatment; the ionization technology adopted by the present invention is a high-sensitivity photoionization technology combining a high-throughput light source with a high-pressure ion source, which can realize high-sensitivity detection; the present invention ionizes all organic and inorganic pollutant gases in the atmosphere through a high-energy photoionization ion source structure; and utilizes a radio frequency quadrupole and a pulse-compensated dual-electrode ion removal technology to remove the high-intensity N2 generated by the mass spectrometer when measuring air. + and O2 + Background ions such as ions can be removed to avoid saturation or damage of ion detector measurements, thereby solving the problem of inability to utilize high-energy photons and the technical application difficulty of excessively high background ion intensity when high-energy photoionization mass spectrometry is used to measure air. The present invention provides a new high-sensitivity online mass spectrometer and detection method for all species of gas-phase pollutants through the combination of high-energy photoionization ion source structure, radio frequency quadrupole and pulse-compensated dual-electrode ion removal technology, achieving high-sensitivity detection of all species of gas-phase pollutants, solving the problem that existing mass spectrometry technology cannot achieve both full coverage and high-sensitivity detection of organic and inorganic pollutant gases in the environment, and expanding the applicable scope of mass spectrometry. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 Schematic diagram of the high-sensitivity online mass spectrometer for all species of gaseous pollutants of the present invention;

[0024] Among them: 1. High-energy photoionization ion source structure, 2. Ion transport structure, 3. Mass spectrometry detection structure, 4. Molecular pump, 5. Discharge chamber, 6. Radio frequency coil, 7. Neon gas inlet tube, 8. Neon gas outlet tube, 9. Arrayed microporous channel plate, 10. Ionization chamber, 11. Injection tube, 12. Radio frequency quadrupole, 13. Electrostatic lens, 14. Pulse extraction electrode, 15. Accelerating electrode, 16. Field-free flight zone, 17. Reflecting electrode, 18. Pulse-compensated dual-electrode ion removal device, 19. Microchannel plate detector, 20. Signal acquisition system, 21. Discharge structure, 22. High-energy photon generation structure. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The purpose of the present invention is to provide a high-sensitivity online mass spectrometer and detection method for all species of gaseous pollutants. By combining a high-energy photoionization ion source structure, a radio frequency quadrupole and a pulse-compensated dual-electrode ion removal device, it can achieve full coverage and high-sensitivity detection of all volatile organic pollutants in the atmosphere and inorganic pollutants such as carbon dioxide, sulfur dioxide, and nitrogen oxides, broaden the applicable scope of mass spectrometry detection, and overcome the problem that existing mass spectrometry cannot take into account both full coverage and high-sensitivity detection of gaseous pollutants.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Example 1

[0029] like Figure 1As shown: This embodiment provides a high-sensitivity online mass spectrometer for all species of gaseous pollutants, including a high-energy photoionization ion source structure 1, an ion transmission structure 2 and a mass spectrometry detection structure 3 connected in sequence. The interiors of the high-energy photoionization ion source structure 1, the ion transmission structure 2 and the mass spectrometry detection structure 3 are all vacuum environments, and the vacuum environments of each structure are provided by a molecular pump 4 respectively; the high-energy photoionization ion source structure 1 includes a high-energy photon generating structure 22, an injection tube 11 and an ionization chamber 10, and the injection tube 11 and the ionization chamber 10 are arranged vertically. The generating structure 22 uses neon as the discharge gas to generate high-energy photons. The high-energy photons are mixed with the gas to be measured that enters through the sampling tube 11 in the ionization chamber 10, and the gas to be measured is ionized. The ion transmission structure 2 includes a radio frequency quadrupole 12 and an electrostatic lens 13. One end of the radio frequency quadrupole 12 corresponds to the outlet of the high-energy photoionization ion source structure 1, and the other end of the radio frequency quadrupole 12 corresponds to the electrostatic lens 13. The radio frequency quadrupole 12 is used to filter non-target background ions and reduce background noise. The electrostatic lens 13 is used to focus the ions. The mass spectrometry detection structure 3 includes a pulse extraction electrode 14, an accelerating electrode 15, a field-free flight zone 16, a reflecting electrode 17, a pulse-compensated dual-electrode ion removal device 18, a microchannel plate detector 19 and a signal acquisition system 20. The ions entering the mass spectrometry detection structure 3 are extracted by the pulse extraction electrode 14 and enter the accelerating electrode 15 for acceleration. The accelerating electrode 15 is located at the entrance on one side of the field-free flight zone 16. The reflecting electrode 17 is provided on the other side of the field-free flight zone 16. An exit is also provided on one side of the field-free flight zone 16. The pulse-compensated dual-electrode ion removal device 18 is provided at the exit. The ions entering the field-free flight zone 16 from the entrance move in the field-free flight zone 16. When they move to the reflecting electrode 17, they are reflected and move in the opposite direction under the action of the reflecting electrode 17 and leave the field-free flight zone 16 from the exit. The pulse-compensated dual-electrode ion removal device 18 is used to further remove non-target background ions. The microchannel plate detector 19 is used to receive ions within a specified mass range controlled by the pulse-compensated dual-electrode ion removal device 18 and output them to the signal acquisition system 20. In this embodiment, the movement direction of ions in the ion transport structure 2 is perpendicular to the movement direction in the mass spectrometry detection structure 3 .

[0030] Specifically, in this embodiment, the high-energy photon generating structure 22 includes a discharge structure 21, a radio frequency coil 6, a neon gas inlet tube 7, and a neon gas outlet tube 8. The radio frequency coil 6 is wound around the discharge structure 21. The discharge structure 21 is cylindrical and includes a discharge chamber 5. The neon gas inlet tube 7 and the neon gas outlet tube 8 are both connected to the discharge chamber 5. The discharge structure 21 is made of quartz. Neon gas enters the discharge chamber 5 through the neon gas inlet tube 7 and flows out through the neon gas outlet tube 8. The pressure within the discharge chamber 5 is 50-1000 Pa.

[0031] In this embodiment, the high-energy photoionization ion source structure 1 further includes an arrayed microporous channel plate 9, disposed between the discharge chamber 5 and the ionization chamber 10. This arrayed microporous channel plate 9 is used to transmit high-energy photons. Using this arrayed microporous channel plate 9, in place of a magnesium fluoride crystal window, allows light to pass through while simultaneously utilizing gas resistance to reduce leakage of discharge gas into the ionization chamber 10 and backflow of the test gas into the discharge chamber 5, thereby maintaining the noble gas pressure within the discharge chamber 5 and maintaining normal luminescence.

[0032] In this embodiment, the discharge chamber 5, the ionization chamber 10, the radio frequency quadrupole 12 and the electrostatic lens 13 are coaxially arranged in sequence.

[0033] In this embodiment, the pulse-compensation dual-electrode ion removal device 18 includes a pulse electrode and a compensation electrode, with a gap of 1-3 mm set between the pulse electrode and the compensation electrode. The pulse electrode provides a forward electric field to allow ions to pass through within a specified pulse width time, and provides a reverse strong electric field to prevent ions from passing through during the rest of the time. The compensation electrode has a reverse stable voltage, which is used to suppress the penetration and baseline drift of non-target background ions and secondary ions.

[0034] In this embodiment, neon is used as the discharge gas. The high-energy photoionization ion source uses neon as the discharge gas. The discharge generates high-energy photons with an energy of 16.67 eV. The high-energy photons pass through the array microporous channel plate 9 and enter the ionization chamber 10. The gas phase substance to be measured enters the ionization chamber 10 through the sampling tube 11 and is ionized by the high-energy photons. Since the ionization energy of most organic and inorganic gases is less than 16.67 eV, the high-energy photons that pass through can ionize all organic and inorganic pollutant gases in the atmosphere. The ions generated by the ionization enter the ion transmission structure 2 from the outlet of the ionization chamber 10, and a large amount of N2 + and O2 + After the non-target background ions are filtered by the radio frequency quadrupole 12, they are focused by the electrostatic lens 13 and enter the mass spectrometry detection structure 3; the ions to be measured are pulsed out, accelerated and reflected before arriving at the pulse-compensated dual-electrode ion removal device 18; the pulse electrode of the pulse-compensated dual-electrode ion removal device 18 provides a positive electric field within a specified pulse width to allow ions to pass through, and ions whose flight time is outside the pulse width time period cannot pass through. The compensation electrode of the pulse-compensated dual-electrode ion removal device 18 has a reverse constant voltage, which is used to suppress the penetration of non-target background ions and secondary ions, thereby further removing the remaining background ions; finally, the ions to be measured obtain mass spectrometry signals through the microchannel plate detector 19 and the signal acquisition system 20.

[0035] In this embodiment, neon is used as the discharge gas to generate high-energy photons with an energy of up to 16.7 eV; an array-type microporous channel plate is used instead of a magnesium fluoride crystal window, and while allowing light to pass, the gas resistance is used to weaken the leakage of the discharge gas into the ionization chamber and the backflow of the gas to be measured into the discharge cavity, thereby maintaining the pressure of the rare gas in the discharge cavity and causing it to emit light normally; since the ionization energy of most organic and inorganic gases is less than 16.67 eV, the high-energy photons that pass through can ionize all organic and inorganic pollutant gases in the atmosphere; the low mass discrimination effect of the radio frequency quadrupole 12 at the ion source outlet is utilized in conjunction with the pulse-compensated dual-electrode ion removal device 18 at the entrance of the ion detector (microchannel plate detector 19) to remove the high-intensity N2 generated by the mass spectrometer when measuring air + and O2 + Background ions can be detected to avoid saturation or damage of the ion detector (microchannel plate detector 19), thereby solving the problem of high-energy photons being unable to be used and the technical application difficulty of excessively high background ion intensity when high-energy photoionization mass spectrometry is used to measure air, thereby achieving high-sensitivity online detection of all species of gaseous pollutants.

[0036] Example 2

[0037] This embodiment provides a method for detecting gaseous pollutants using the all-species high-sensitivity online mass spectrometer of embodiment 1, comprising the following steps:

[0038] Step 1: Use a molecular pump 4 to provide the required vacuum environment for the high-energy photoionization ion source, the ion transport structure 2, and the mass spectrometry detection structure 3;

[0039] Step 2: Neon gas enters the discharge chamber 5 through the neon gas inlet pipe 7 and flows out through the neon gas outlet pipe 8, maintaining a certain pressure in the discharge chamber 5; the radio frequency coil 6 excites the neon gas in the discharge chamber 5 to produce high-energy photons;

[0040] Step 3: High-energy photons pass through the arrayed microporous channel plate 9 and enter the ionization chamber 10, where they mix with the gas to be measured introduced by the sample inlet tube 11 and ionize the gas to be measured.

[0041] Step 4: The ions generated by ionization enter the ion transmission structure 2 from the outlet of the ionization chamber 10, and a large amount of N2 + and O2 + After the non-target background ions are filtered by the radio frequency quadrupole 12, they are focused by the electrostatic lens 13 and enter the mass spectrometer detection structure 3;

[0042] Step 5: The ions entering the mass spectrometer detection structure 3 are extracted by the forward electric field provided by the pulse extraction electrode 14; then, under the action of the acceleration electrode 15, the ions enter the field-free flight region 16 at a high speed. After flying at a constant speed for a period of time, they are repelled by the reverse electric field provided by the reflection electrode 17, and the ions move in the opposite direction;

[0043] Step 6: The ions reach the pulse-compensated dual-electrode ion removal device 18 to further remove the remaining non-target background ions;

[0044] Step 7: Ions within the specified mass range are received by the microchannel plate detector 19 and output to the signal acquisition system 20 .

[0045] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A highly sensitive online mass spectrometer for all species of gaseous pollutants, characterized by: It comprises a high-energy photoionization ion source structure, an ion transmission structure and a mass spectrometry detection structure which are connected in sequence; the high-energy photoionization ion source structure comprises a high-energy photon generating structure, an injection tube and an ionization chamber, the high-energy photon generating structure uses neon as a discharge gas to generate high-energy photons, the high-energy photons are mixed with the gas to be measured which enters through the injection tube in the ionization chamber, and the gas to be measured is ionized; the ion transmission structure comprises a radio frequency quadrupole and an electrostatic lens, one end of the radio frequency quadrupole corresponds to the outlet of the high-energy photoionization ion source structure, the other end of the radio frequency quadrupole corresponds to the electrostatic lens, the radio frequency quadrupole is used to filter non-target background ions, and the electrostatic lens is used to focus ions; the mass spectrometry detection structure comprises a pulse extraction electrode, an acceleration electrode, a field-free flight zone, a reflection electrode, a pulse-compensation dual-electrode ion removal device, a microchannel plate detector and A signal acquisition system, wherein ions entering the mass spectrometry detection structure are extracted by the pulse extraction electrode and enter the accelerating electrode for acceleration, the accelerating electrode is located at an entrance on one side of the field-free flight zone, the reflecting electrode is provided on the other side of the field-free flight zone, and an exit is also provided on one side of the field-free flight zone, the pulse-compensating dual-electrode ion removal device is provided at the exit, ions entering the field-free flight zone from the entrance move in the field-free flight zone, and when they move to the reflecting electrode, they are reflected and move in the opposite direction under the action of the reflecting electrode, and leave the field-free flight zone from the exit, the pulse-compensating dual-electrode ion removal device is used to further remove non-target background ions, and the microchannel plate detector is used to receive ions within a specified mass range controlled by the pulse-compensating dual-electrode ion removal device, and output them to the signal acquisition system; The high-energy photon generating structure includes a discharge structure, and the discharge structure is provided with a discharge cavity; The high-energy photoionization ion source structure further includes an arrayed microporous channel plate, which is disposed between the discharge cavity and the ionization chamber and is used to transmit high-energy photons. The pulse-compensation dual-electrode ion removal device includes a pulse electrode and a compensation electrode, with a gap set between the pulse electrode and the compensation electrode. The pulse electrode provides a forward electric field to allow ions to pass through during a specified pulse width time, and provides a reverse strong electric field to prevent ions from passing through during the rest of the time. The compensation electrode has a reverse stable voltage for suppressing the penetration and baseline drift of non-target background ions and secondary ions.

2. The high-sensitivity online mass spectrometer for all species of gaseous pollutants according to claim 1, characterized in that: The high-energy photon generating structure includes a radio frequency coil, a neon gas inlet pipe and a neon gas outlet pipe. The radio frequency coil is wound on the discharge structure. Both the neon gas inlet pipe and the neon gas outlet pipe are connected to the discharge cavity.

3. The high-sensitivity online mass spectrometer for all species of gaseous pollutants according to claim 2, characterized in that: The discharge structure is made of quartz, and the gas pressure in the discharge chamber is 50-1000 Pa.

4. The high-sensitivity online mass spectrometer for all species of gaseous pollutants according to claim 1, characterized in that: The discharge chamber, the ionization chamber, the radio frequency quadrupole and the electrostatic lens are coaxially arranged in sequence.

5. The high-sensitivity online mass spectrometer for all species of gaseous pollutants according to claim 1, characterized in that: The interiors of the high-energy photoionization ion source structure, the ion transmission structure, and the mass spectrometry detection structure are all vacuum environments.

6. A method for detecting gaseous pollutants using the high-sensitivity online mass spectrometer according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: Providing a vacuum environment for the high-energy photoionization ion source, ion transmission structure, and mass spectrometry detection structure; Step 2: Neon gas enters the discharge chamber through the neon gas inlet pipe and flows out through the neon gas outlet pipe, maintaining a certain pressure in the discharge chamber. The radio frequency coil excites the neon gas in the discharge chamber to produce high-energy photons. Step 3: High-energy photons pass through the arrayed microporous channel plate into the ionization chamber, mix with the gas to be tested introduced by the inlet tube, and ionize the gas to be tested; Step 4: The ions generated by ionization enter the ion transmission structure from the outlet of the ionization chamber. Some non-target background ions are filtered by the radio frequency quadrupole and then focused by the electrostatic lens into the mass spectrometer detection structure; Step 5: Ions entering the mass spectrometer detection structure are extracted by the positive electric field provided by the pulse extraction electrode. Then, under the action of the accelerating electrode, the ions enter the field-free flight region. After a period of uniform flight, they are repelled by the reverse electric field provided by the reflecting electrode, and the ions move in the opposite direction. Step 6: The ions reach the pulse-compensated dual-electrode ion removal device to further remove the remaining non-target background ions; Step 7: Ions within the specified mass range are received by the microchannel plate detector and output to the signal acquisition system.

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