Multi-stage vacuum system capable of respectively regulating pressure for mass spectrometer

Abstract

The utility model provides a multistage vacuum system capable of respectively regulating pressure for a mass spectrum, and belongs to the technical field of mass spectrometers. The device comprises a multi-stage vacuum cavity and a vacuum pump for vacuumizing the multi-stage vacuum cavity, the multi-stage vacuum cavity at least comprises a first-stage vacuum cavity body, a second-stage vacuum cavity body, a third-stage vacuum cavity body, a fourth-stage vacuum cavity body and a fifth-stage vacuum cavity body. The air pressure requirements of different structural units of the space tandem mass spectrometer can be met, and particularly, the requirements that the working air pressure range of the collision reaction tank is relatively high and the working air pressure of the mass analyzers on the two sides is relatively low are met, so that the sample testing requirement in the total mass range is met, the instrument sensitivity is improved, and the test cost is reduced. The interference in the test can be effectively removed, the test performance of an instrument is obviously improved, and trace or ultra-trace detection is realized.

Description

Technical Field

[0001] This utility model relates to the field of mass spectrometry technology, and in particular to a multi-stage vacuum system with individually adjustable pressure for mass spectrometers. Background Technology

[0002] A mass spectrometer is a chemical analysis instrument used to analyze and detect ions with different mass-to-charge ratios. Different mass spectrometers can be used to detect samples with different forms and characteristics, such as organic and inorganic ions. Ions are generally generated at the ion source at the very front of the mass spectrometer and are detected after reaching the detector through an ion transport system. Traditional mass spectrometers use vacuum systems (such as...) Figure 1 As shown in the image, while it can achieve high sensitivity, wide dynamic range, and simultaneous determination of multiple elements / ions, it suffers from severe mass spectrometry interference in samples with complex matrices for trace or ultra-trace element detection. One of the main methods to solve this problem is spatial tandem mass spectrometry. Spatial tandem mass spectrometry can use collisional reactions to remove impurity interference, enabling the detection of trace or ultra-trace elements in complex matrices. In addition, spatial tandem mass spectrometry can also realize various other testing modes to meet different testing needs.

[0003] There are many types of space tandem mass spectrometers, the most common being the triple quadrupole mass spectrometer, which consists of two quadrupole mass analyzers connected in series. Between them is a collision reaction cell containing multiple stages of ion guide rods. By pressurizing the collision or reaction gas, potential interfering ions can be selectively attenuated, or the target analyte can be fragmented under the influence of the collision gas. In MS / MS mode, both quadrupoles act as unit mass filters. This configuration can eliminate mass spectrometric interferences, including isotope interference, double charge interference, and polyatomic ion overlap, in inorganic mass spectrometry; and in organic mass spectrometry, it can eliminate mass spectrometric interferences from other target analytes and fragment the target analyte. However, adding a quadrupole stage and a collision / reaction cell also introduces reduced ion transmission efficiency and a higher operating pressure for the quadrupole mass analyzer and detector, which can lead to discharge risks. Ensuring a high pressure in the collision reaction cell and a low operating pressure for the mass analyzer and detector, while improving the transmission efficiency of target ions, is one of the design challenges of space tandem mass spectrometers.

[0004] Currently, there is a lot of research on the design of three-stage vacuum structures, but there is little existing technology on the design of adjustable-pressure multi-stage vacuum systems, which is an important direction for the improvement of vacuum systems in space tandem mass spectrometers. Utility Model Content

[0005] In view of this, in order to solve the technical problem that most existing space tandem mass spectrometer vacuum systems are three-stage vacuum structures and lack adjustable pressure multi-stage vacuum systems, this utility model provides a multi-stage vacuum system for mass spectrometry with individually adjustable pressure. It can meet the gas pressure requirements of different structural units of the space tandem mass spectrometer, especially the requirement that the working gas pressure range of the collision reaction cell is relatively high, while the working gas pressure of the mass analyzers on both sides is relatively low. This allows it to meet the sample testing requirements of the entire mass range, improve instrument sensitivity, effectively remove interference in the test, significantly improve the instrument's testing performance, and achieve trace or ultra-trace detection.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A multi-stage vacuum system with individually adjustable pressure for a mass spectrometer includes a multi-stage vacuum chamber and a vacuum pump for evacuating the multi-stage vacuum chamber.

[0008] The multi-stage vacuum cavity includes at least the following cavities:

[0009] The first-stage vacuum chamber is used to extract ionized samples from an atmospheric pressure ion source.

[0010] The second-stage vacuum chamber is equipped with an extraction and guiding device for extracting and guiding the ion beam transmitted from the first-stage vacuum chamber and transmitting it to the third-stage vacuum chamber.

[0011] The third-stage vacuum chamber contains a first-stage mass analyzer, which is used to separate the ion beam transmitted from the second-stage vacuum chamber and control the ion beam of a specific mass number to pass through the first-stage mass analyzer.

[0012] The fourth-stage vacuum chamber contains a collision reaction pool, which is used to introduce collision gas or reaction gas to reduce interference in the ion beam transmitted from the third-stage vacuum chamber, or to obtain fragment information after the target object is broken up.

[0013] The fifth-stage vacuum chamber contains a second-stage mass analyzer and a detector. The second-stage mass analyzer is used to separate the ion beam transmitted through the fourth-stage vacuum chamber. The ion beam with a specific mass number is controlled to pass through the second-stage mass analyzer and then enter the detector to obtain a mass spectrometry signal.

[0014] Preferably, the atmospheric pressure ion source includes one of an ICP source, an APCI source, and an ESI source.

[0015] Preferably, the working pressure inside the first-stage vacuum chamber is from 100 Pa to 1.013 × 10⁻⁶ Pa. 5 Pa.

[0016] Preferably, the working pressure inside the second-stage vacuum chamber is 0.01 Pa to 10 Pa.

[0017] Preferably, the working gas pressure inside the third-stage vacuum chamber is 1×10⁻⁶. -5 Pa to 1×10 -3 Pa.

[0018] Preferably, the working gas pressure inside the fourth-stage vacuum chamber is 1×10⁻⁶. -3 Pa to 1×10 -1 Pa.

[0019] Preferably, the working gas pressure inside the fifth-stage vacuum chamber is 1×10⁻⁶. -5 Pa to 1×10 -3 Pa.

[0020] Preferably, the extraction guiding device is one of an electrostatic lens group, an ion funnel, an ion drift tube, and a multipole guiding structure.

[0021] Preferably, the first-stage mass analyzer is a quadrupole mass analyzer or an ion trap mass analyzer.

[0022] Preferably, the collision reaction cell is used for inorganic mass spectrometry or organic mass spectrometry; it is equipped with either a multipole or an ion trap.

[0023] Preferably, the second-stage mass analyzer includes one of a quadrupole mass analyzer, an ion trap mass analyzer, and a time-of-flight analyzer.

[0024] Preferably, the detector comprises one of a Faraday cup, a split darad electron multiplier, a channel electron multiplier, a microchannel plate, and a scintillation photomultiplier.

[0025] Preferably, the vacuum pump is a multi-stage vacuum pump.

[0026] Preferably, the multi-stage vacuum pump includes at least a primary vacuum pump and a secondary vacuum pump that are connected in series.

[0027] The primary vacuum pump is a rotary oil-sealed pump, and the secondary vacuum pump is a molecular pump.

[0028] Preferably, the molecular pump is a single-port molecular pump and / or a multi-port molecular pump;

[0029] The single-port molecular pump is used to evacuate a single vacuum chamber, and the multi-port molecular pump is used to evacuate multiple vacuum chambers.

[0030] Preferably, the multi-stage vacuum pump further includes a three-stage vacuum pump, which is an ion pump.

[0031] Preferably, the diameter of the connecting hole between each vacuum chamber is between 0.5 and 10 mm. The working gas pressure inside the vacuum chamber can be adjusted by changing the pumping speed of the vacuum pump, the size of the connecting hole, and the inlet gas flow rate.

[0032] Preferably, the multi-stage vacuum chamber is manufactured using a one-time molding process or assembled in stages.

[0033] Compared with the prior art, this utility model has the following beneficial effects:

[0034] This invention provides a multi-stage vacuum system for mass spectrometers with individually adjustable pressure. Through the design of multi-stage vacuum chambers, it can meet the gas pressure requirements of different structural units in a space tandem mass spectrometer, satisfying the gas pressure requirements of both inorganic and organic space tandem mass spectrometers. It allows for flexible adjustment of the working gas pressure of specific chambers, particularly meeting the requirement of a higher working gas pressure range for the collision reaction cell in the MSn reaction while maintaining lower working gas pressures for the mass analyzers on both sides. This satisfies the sample testing needs across the entire mass range, improves instrument sensitivity, effectively removes interference during testing, reduces background interference, allows more target ions to enter the detector, effectively improves ion transmission efficiency, reduces background noise, significantly enhances instrument testing performance, and enables trace or ultra-trace detection, thereby improving the sensitivity of the mass spectrometer. Attached Figure Description

[0035] Figure 1 For traditional mass spectrometer vacuum systems, among which, Figure 1 P1, P2, and P3 in the diagram represent the first-stage vacuum chamber, the second-stage vacuum chamber, and the third-stage vacuum chamber, respectively, forming a three-stage vacuum system structure.

[0036] Figure 2 This is a schematic diagram of the independently adjustable multi-stage vacuum system for a mass spectrometer according to this invention, wherein P1, P2, P3, and P4 correspond to the first to fourth stage vacuum chambers, respectively. 5+N (N is an integer and ≥0) represents a vacuum cavity of level 5 and above;

[0037] Figure 3 This is a schematic diagram of the first space tandem mass spectrometer with a five-stage vacuum system;

[0038] Figure 4 This is a schematic diagram of a second type of space tandem mass spectrometer with a five-stage vacuum system;

[0039] Figure 5 Ion intensity graphs for different pore sizes;

[0040] In the diagram, 1. First-stage vacuum chamber; 2. Second-stage vacuum chamber; 3. Third-stage vacuum chamber; 4. Fourth-stage vacuum chamber; 5. Fifth-stage vacuum chamber; 6. Single-port molecular pump; 7. Two-port molecular pump; 8. Vacuum pump; 9. Extraction structure; 10. Extraction guiding device; 11. First-stage mass analyzer; 12. Collision reaction cell; 13. Second-stage mass analyzer; 14. Detector. Detailed Implementation

[0041] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0042] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0043] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0044] First, as Figure 2-5 As shown, a multi-stage vacuum system with individually adjustable pressure for a mass spectrometer includes a multi-stage vacuum chamber and a vacuum pump 8 for evacuating the multi-stage vacuum chamber.

[0045] The multi-stage vacuum cavity includes at least the following cavities:

[0046] The first-stage vacuum chamber 1 is used to extract ionized samples from an atmospheric pressure ion source;

[0047] The preferred working pressure of the first-stage vacuum chamber 1 is between 100 Pa and 1.013 × 10⁻⁶ Pa. 5Pa (standard atmosphere).

[0048] Atmospheric pressure ion source is preferably one of ICP source, APCI source and ESI source, which can be selected according to actual needs and no special requirements are made. The extraction structure 9 is preferably selected from the skimmer group in the mass spectrometer.

[0049] The second-stage vacuum chamber 2 is equipped with an extraction and guiding device 10, which is used to extract and guide the ion beam transmitted from the first-stage vacuum chamber and transmit it to the third-stage vacuum chamber.

[0050] The working pressure of the second-stage vacuum chamber 2 is preferably 0.01 Pa to 10 Pa;

[0051] The third-stage vacuum chamber 3 is equipped with a first-stage mass analyzer 11, which is used to separate the ion beam transmitted from the second-stage vacuum chamber and control the ion beam of a specific mass number to pass through the first-stage mass analyzer 11.

[0052] The preferred working pressure for the third-stage vacuum chamber 3 is 1×10⁻⁶. -5 Pa to 1×10 -3 Pa;

[0053] The fourth-stage vacuum chamber 4 is equipped with a collision reaction pool 12, which is used to introduce collision gas or reaction gas to reduce interference in the ion beam transmitted from the third-stage vacuum chamber, or to obtain fragment information after the target object is broken up. Preferably, the introduction of collision gas or reaction gas does not affect the optimal working gas pressure of the preceding and following vacuum chambers.

[0054] The working pressure inside the fourth-stage vacuum chamber 4 is 1×10⁻⁶. -3 Pa to 1×10 -1 Pa;

[0055] The fifth-stage vacuum chamber 5 is equipped with a second-stage mass analyzer 13 and a detector 14. The second-stage mass analyzer 13 is used to separate the ion beam transmitted through the fourth-stage vacuum chamber 4. The ion beam with a specific mass number is controlled to enter the detector 14 after passing through the second-stage mass analyzer 13, thereby obtaining a mass spectrometry signal.

[0056] The working gas pressure inside the fifth-stage vacuum chamber 5 is 1×10⁻⁶. -5 Pa to 1×10 -3 Pa.

[0057] In this invention, the extraction guiding device 10 includes, but is not limited to, one of an electrostatic lens group, an ion funnel, an ion drift tube, and a multipole guiding structure, which can be selected according to actual needs.

[0058] In this invention, the first-stage mass analyzer 11 includes, but is not limited to, a quadrupole mass analyzer or an ion trap mass analyzer, which can be selected according to actual needs.

[0059] In this invention, the collision reaction cell 12 is used for inorganic mass spectrometry analysis or organic mass spectrometry analysis; it is equipped with either a multi-stage bar or an ion trap, which can be selected according to actual needs, wherein the multi-stage bar is preferably a six-stage bar.

[0060] In this invention, the second-stage mass analyzer 13 includes, but is not limited to, one of a quadrupole mass analyzer, an ion trap mass analyzer, and a time-of-flight analyzer, which can be selected according to actual needs.

[0061] In this invention, the detector includes, but is not limited to, one of the following: Faraday cup, split darad electron multiplier, channel electron multiplier, microchannel plate, and scintillation photomultiplier.

[0062] This invention merely provides an exemplary vacuum system for the aforementioned five-stage vacuum chamber. Those skilled in the art can also select vacuum systems of five or more stages, such as seven-stage or nine-stage systems, according to actual needs.

[0063] Each vacuum chamber preferably has inlet and outlet ports. The working pressure inside the target vacuum chamber is adjusted by controlling the inlet airflow rate, adjusting the diameter of the connecting holes between chambers, and changing the pumping speed of the vacuum pump 8. When the system has more vacuum stages (five or more), the added intermediate vacuum stages generally contain the nth stage focusing guide device, the nth stage mass analyzer, or the nth stage collision reaction cell, but the detector 14 is always located in the last vacuum stage. The multi-stage vacuum chambers are connected by micropores, grids, or slits with sealing rings. Except for the first-stage vacuum chamber, all other vacuum chambers need to be connected to the vacuum pump 8 to control the vacuum level of each stage.

[0064] It should be noted that the optimal working gas pressure may vary for samples under different reaction gases and needs to be adjusted according to the actual situation.

[0065] In summary, this invention, through the design of a multi-stage vacuum chamber, can meet the gas pressure requirements of different structural units of a space tandem mass spectrometer. In particular, it can simultaneously meet the requirements of a high working gas pressure range in the collision / reaction cell of the MSn reaction, while the working gas pressure of the mass analyzers on both sides is relatively low. This allows it to meet the sample testing requirements across the entire mass range, improve instrument sensitivity, effectively remove interference during testing, significantly improve the instrument's testing performance, and achieve trace or ultra-trace detection.

[0066] In this invention, the vacuum pump 8 is a multi-stage vacuum pump, such as a two-stage or higher vacuum pump.

[0067] In this invention, the multi-stage vacuum pump includes at least a primary vacuum pump and a secondary vacuum pump that are connected in series.

[0068] The primary vacuum pump includes, but is not limited to, a rotary oil-sealed pump, and the secondary vacuum pump includes, but is not limited to, a molecular pump.

[0069] Preferably, the molecular pump is a single-port molecular pump 6 and / or a multi-port molecular pump;

[0070] The single-port molecular pump 6 is used to evacuate a single vacuum chamber, while the multi-port molecular pump is used to evacuate multiple vacuum chambers. It should be noted that the multi-port molecular pump has the ability to individually control the evacuation speed of each port. The single-port molecular pump 6 is preferably used to evacuate any stage of vacuum chamber; the first-stage vacuum chamber may not require direct evacuation by the single-port molecular pump 6, but only by a primary vacuum pump.

[0071] For example, the vacuum system uses a two-stage vacuum pump. The primary vacuum pump is a rotary oil-sealed pump, and the secondary vacuum pump includes two single-port molecular pumps 6. A double-port molecular pump 7 is used between the second-stage vacuum chamber and the third-stage vacuum chamber. The two single-port molecular pumps 6 evacuate the fourth-stage vacuum chamber and the fifth-stage vacuum chamber respectively, thereby achieving the purpose of saving costs.

[0072] In this invention, the multi-stage vacuum pump also includes a three-stage vacuum pump, which is an ion pump.

[0073] In this invention, the pumping speed of the molecular pump can be controlled independently in each vacuum chamber. Each vacuum chamber is connected by a connecting hole, and the diameter of the connecting hole between each vacuum chamber is between 0.5-10 mm. The working gas pressure in the vacuum chamber can be adjusted by changing the pumping speed of the vacuum pump, the size of the connecting hole, and the inlet gas flow rate.

[0074] In this invention, the multi-stage vacuum chamber is manufactured using a one-time molding process or assembled in stages.

[0075] The working principle of the adjustable multi-stage vacuum system for mass spectrometer provided by this utility model is as follows:

[0076] First, ions are extracted from an atmospheric pressure ion source using the extraction structure 9 (skimmer group in the mass spectrometer) inside the first-stage vacuum chamber; the extraction guiding device 10 inside the second-stage vacuum chamber transports and cools charged ions, removing neutral ions; the first mass analyzer inside the third-stage vacuum chamber further extracts and analyzes ions; the fourth-stage vacuum chamber uses a collision reaction cell 12 to remove interfering ions; and the second mass analyzer inside the fifth-stage vacuum chamber extracts ions and transports them into the detector 14, thus completing the entire analysis process.

[0077] Secondly, the cavity containing the collision reaction tank 12 requires a higher working gas pressure, while the mass analyzers on both sides require a lower working gas pressure. This invention can adjust the gas pressure of the target cavity by changing the pumping speed of the molecular pump, the size of the connecting orifice between the cavities, and controlling the inlet gas flow rate.

[0078] Finally, through practical verification on a triple-stage, four-level experimental platform, it was found that different air pressures in the collision cell do indeed affect the reaction efficiency, thereby affecting the noise intensity; the operating air pressure of the mass analyzer does indeed affect the signal strength and resolution. Adjusting the air pressure of different stages of the chamber to a suitable level can yield better test results without affecting the quality of the mass analyzer's operation.

[0079] Secondly, this utility model also provides the application of the above-mentioned adjustable multi-stage vacuum system for mass spectrometers in a space tandem mass spectrometer.

[0080] In this invention, the space tandem mass spectrometer is an inductively coupled plasma triple quadrupole mass spectrometer.

[0081] The technical solution of this utility model will be clearly and thoroughly described below with reference to specific embodiments.

[0082] Example 1

[0083] Embodiment 1 of this utility model utilizes... Figure 4 The vacuum system shown is used to construct a triple quadrupole experimental platform. The apertures of different connecting holes between the fourth and fifth vacuum chambers are adjusted to 1 mm and 5 mm, respectively. Each molecular pump is kept at full speed. Oxygen is introduced into the fourth vacuum chamber as the collision reaction gas at a constant flow rate of 5 ml / min. This is used to test target substances in complex matrices. 111 Cd (Cd in 100ppm Mo solution, 10ppb), interfering substances are 95 Mo 16 O. When the diameter of the connecting hole between the two vacuum chambers was changed from 1 mm to 5 mm, and oxygen was introduced for 10 minutes, the vacuum value of the fifth vacuum chamber increased from 1.6 × 10⁻⁶. -5 Pa rose to 1.6 × 10 -4 Pa, as the vacuum in the vacuum chamber containing the final stage mass analyzer rises, the target material 111 The Cd signal strength decreased from 6000 to 1000, indicating interference under both experimental conditions. 95 Mo 16 The intensity of O is basically 0~20 cps, which proves that the triple quadrupole vacuum system has the function of removing interference, and the gas pressure of the fifth-stage vacuum chamber significantly affects the signal intensity of the target analyte.

[0084] Example 2

[0085] use Figure 4 The vacuum system shown is a triple quadrupole experimental platform. Each molecular pump maintains a constant pumping speed. The aperture of the connecting hole between the third and fourth vacuum chambers is a fixed value between 1-5 mm, and the aperture of the connecting hole between the fourth and fifth vacuum chambers is also a fixed value between 1-5 mm. Oxygen is introduced into the fourth vacuum chamber as the collision reaction gas, and the oxygen flow rate is adjusted from 0 to 5 ml / min. The target substance in a complex matrix is ​​then tested. 111 Cd (Cd in 100ppm Mo solution, 10ppb), interfering substances are 95 Mo 16 O. As oxygen flow rate increases, interfering substances 95 Mo 16 The oxygen intensity gradually decreases, reaching 0-20 cps after a certain critical value. The vacuum value of the third-stage vacuum chamber is observed to be 1.6 × 10⁻⁶. -4 Pa, fifth-stage vacuum chamber pressure 2×10 -5 Pa, which meets the working pressure requirements of the quadrupole mass analyzer.

[0086] The diameters of the connecting orifices between the third and fourth vacuum chambers of the platform were adjusted to 1 mm and 4 mm, respectively, while maintaining a constant pumping speed for each molecular pump. Oxygen was introduced into the fourth vacuum chamber as the collision reaction gas at a constant flow rate of 2 ml / min. When the connecting orifice diameter between the two vacuum chambers was increased from 1 mm to 4 mm, and oxygen was introduced, the vacuum value of the third vacuum chamber increased from 1.2 × 10⁻⁶ mm. -4 Pa up to 1.7 × 10 -4 Pa, the change was not significant; the working pressure of the fourth-stage vacuum chamber increased from 1.7 × 10⁻⁶ Pa. -2 Pa decreased to 1.2 × 10 -3 Pa, the fifth-stage vacuum chamber is always 2 × 10 Pa. -5 Near Pa. At different apertures, the same interfering substances... 95 Mo 16 O and analytes 111 Cd is used for evaluation of interfering substances. 95 Mo 16 The intensity of O is between 0 and 20 cps, proving that the triple quadruped vacuum system has the function of removing interference.

[0087] like Figure 5 As shown, comparing the intensity values ​​of Be, In, and U at 1 ppb concentrations under four different pore sizes, the signal intensity tends to increase with increasing pore size, which may be related to the diameter of the ion transport channel. Without affecting the working pressure of the adjacent vacuum chamber, a design with a larger pore size should be selected to improve ion transport efficiency.

[0088] The above are merely preferred embodiments of this utility model; however, the scope of protection of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this utility model, based on the technical solution and its improved concept, should be included within the scope of protection of this utility model.

Claims

1. A multi-stage vacuum system with individually adjustable pressure for a mass spectrometer, characterized in that, It includes a multi-stage vacuum chamber and a vacuum pump for evacuating the multi-stage vacuum chamber; The multi-stage vacuum cavity includes at least the following cavities: The first-stage vacuum chamber is used to extract ionized samples from an atmospheric pressure ion source. The second-stage vacuum chamber is equipped with an extraction and guiding device for extracting and guiding the ion beam transmitted from the first-stage vacuum chamber and transmitting it to the third-stage vacuum chamber. The third-stage vacuum chamber contains a first-stage mass analyzer, which is used to separate the ion beam transmitted from the second-stage vacuum chamber and control the ion beam of a specific mass number to pass through the first-stage mass analyzer. The fourth-stage vacuum chamber contains a collision reaction pool, which is used to introduce collision gas or reaction gas to reduce interference in the ion beam transmitted from the third-stage vacuum chamber, or to obtain fragment information after the target object is broken up. The fifth-stage vacuum chamber contains a second-stage mass analyzer and a detector. The second-stage mass analyzer is used to separate the ion beam transmitted through the fourth-stage vacuum chamber. The ion beam with a specific mass number is controlled to pass through the second-stage mass analyzer and then enter the detector to obtain a mass spectrometry signal.

2. The adjustable-voltage multi-stage vacuum system for a mass spectrometer according to claim 1, characterized in that, The atmospheric pressure ion source includes one of the following: ICP source, APCI source, and ESI source.

3. The adjustable-pressure multi-stage vacuum system for a mass spectrometer according to claim 1, characterized in that, The working pressure within the first-stage vacuum chamber is 100 Pa to 1.013 × 10⁻⁶ Pa. 5 Pa.

4. A multi-stage vacuum system for a mass spectrometer with individually adjustable pressure according to claim 1, characterized in that, The working pressure inside the second-stage vacuum chamber is 0.01 Pa to 10 Pa.

5. A multi-stage vacuum system for a mass spectrometer with individually adjustable pressure according to claim 1, characterized in that, The working pressure inside the third-stage vacuum chamber is 1×10⁻⁶. -5 Pa to 1×10 -3 Pa.

6. A multi-stage vacuum system for a mass spectrometer with individually adjustable pressure according to claim 1, characterized in that, The working pressure inside the fourth-stage vacuum chamber is 1×10⁻⁶. -3 Pa to 1×10 -1 Pa.

7. A multi-stage vacuum system for a mass spectrometer with individually adjustable pressure according to claim 1, characterized in that, The working pressure inside the fifth-stage vacuum chamber is 1×10⁻⁶. -5 Pa to 1×10 -3 Pa.

8. A multi-stage vacuum system for a mass spectrometer with individually adjustable pressure according to claim 1, characterized in that, The extraction guiding device is one of the following: an electrostatic lens group, an ion funnel, an ion drift tube, and a multipole guiding structure.

9. A multi-stage vacuum system for a mass spectrometer with individually adjustable pressure according to claim 1, characterized in that, The first-stage mass analyzer is a quadrupole mass analyzer or an ion trap mass analyzer.

10. A multi-stage vacuum system for a mass spectrometer with individually adjustable pressure according to claim 1, characterized in that, The collision reaction cell is used for inorganic or organic mass spectrometry analysis; it is equipped with multipolar rods or ion traps.

11. A multi-stage vacuum system for a mass spectrometer with individually adjustable pressure according to claim 1, characterized in that, The second-stage mass analyzer includes one of a quadrupole mass analyzer, an ion trap mass analyzer, and a time-of-flight analyzer.

12. A multi-stage vacuum system for a mass spectrometer with individually adjustable pressure according to claim 1, characterized in that, The detector includes one of the following: Faraday cup, split darad electron multiplier, channel electron multiplier, microchannel plate, and scintillation photomultiplier.

13. A multi-stage vacuum system for a mass spectrometer with individually adjustable pressure according to claim 1, characterized in that, The vacuum pump is a multi-stage vacuum pump.

14. A multi-stage vacuum system for a mass spectrometer with individually adjustable pressure according to claim 13, characterized in that, The multistage vacuum pump includes at least a primary vacuum pump and a secondary vacuum pump that are connected in series. The primary vacuum pump is a rotary oil-sealed pump, and the secondary vacuum pump is a molecular pump.

15. A multi-stage vacuum system for a mass spectrometer with individually adjustable pressure according to claim 14, characterized in that, The molecular pump is a single-port molecular pump and / or a multi-port molecular pump. The single-port molecular pump is used to evacuate a single vacuum chamber, and the multi-port molecular pump is used to evacuate multiple vacuum chambers.

16. A multi-stage vacuum system for a mass spectrometer with individually adjustable pressure according to claim 14, characterized in that, The multi-stage vacuum pump also includes a three-stage vacuum pump, which is an ion pump.

17. A multi-stage vacuum system for a mass spectrometer with individually adjustable pressure according to claim 1, characterized in that, The diameter of the connecting hole between each vacuum chamber is between 0.5-10 mm. The working gas pressure inside the vacuum chamber can be adjusted by changing the pumping speed of the vacuum pump, the size of the connecting hole, and the inlet gas flow rate.

18. A multi-stage vacuum system for a mass spectrometer with individually adjustable pressure according to any one of claims 1-17, characterized in that, The multi-stage vacuum chamber is manufactured using a one-time molding process or assembled in stages.

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