A miniature liquid chromatography-mass spectrometer based on high-precision voltage measurement

Abstract

This invention relates to the field of liquid chromatography-mass spectrometry (LC-MS), specifically a small LC-MS based on high-precision voltage measurement. It includes a housing with a shell bolted to the top. Inside the shell are a primary chamber, a secondary chamber, and a mounting area, arranged vertically. An ion funnel is located inside the primary chamber, and a conical plate is bolted to the top of the inner wall of the secondary chamber. The linear ion trap of this invention is a dual-potential-well plane, capable of separately collecting incoming ions and controlling the cooling and ejection of confined ions. Compared to a single-potential-well plane ion trap, it provides more thorough ion collection and focusing. Furthermore, the working cycle, ion flux, and ejected ions of the dual-potential-well plane ion trap meet the requirements of a multiple reflection time-of-flight mass spectrometer (MRFMS), and it can be coupled to provide high-flux, state-concentrated introduced ions, significantly improving the detection accuracy and precision of the LC-MS.

Description

Technical Field

[0001] This invention relates to the field of liquid chromatography-mass spectrometry (LC-MS), specifically to a small LC-MS based on high-precision voltage measurement. Background Technology

[0002] Liquid chromatography-mass spectrometry (LC-MS) is an instrument that combines liquid chromatography with mass spectrometry. It combines the ability of liquid chromatography to effectively separate thermally unstable and high-boiling-point compounds with the strong component identification capabilities of mass spectrometry. It is an effective method for separating and analyzing complex organic mixtures.

[0003] Chinese Patent Publication No. CN112420479B discloses a miniature mass spectrometer, comprising: an ionization source for converting sample molecules into gaseous ions in a region substantially at atmospheric pressure; a capture device for capturing and storing ions; and a discontinuous atmospheric pressure interface device for transferring ions from the substantially atmospheric pressure region to at least one other region with reduced pressure, wherein the atmospheric pressure interface device includes a valve for controlling the entry or cessation of ion entry into the capture device, and ions are transferred to the capture device in a discontinuous manner by repeatedly opening the valve, thereby capturing and enriching ions; it also includes a mass analyzer, a detector, circuitry, a vacuum chamber, a vacuum pump, a barometer, and a computer; this invention provides a miniature mass spectrometer capable of improving sensitivity and ion detection limits, and enhancing ion intensity stability.

[0004] From the above patents and existing liquid chromatography-mass spectrometers, it can be found that existing liquid chromatography-mass spectrometers have the following shortcomings: the linear ion trap in traditional liquid chromatography-mass spectrometers is a single potential trap plane, which is insufficient for the collection and focusing of ions, resulting in the liquid chromatography-mass spectrometer being unable to accurately detect the composition of the substance to be detected, thus affecting the detection accuracy of the liquid chromatography-mass spectrometer. Therefore, there is an urgent need to develop a small liquid chromatography-mass spectrometer based on high-precision voltage measurement. Summary of the Invention

[0005] In view of the problems existing in a small liquid chromatography-mass spectrometer based on high-precision voltage measurement, the present invention is proposed.

[0006] Therefore, the purpose of this invention is to provide a small liquid chromatography-mass spectrometer based on high-precision voltage measurement, which solves the problem that the linear ion trap in traditional liquid chromatography-mass spectrometers is a single potential trap plane, which is insufficient for ion collection and focusing, resulting in the liquid chromatography-mass spectrometer being unable to accurately detect the composition of the substance to be detected, thus affecting the detection accuracy of the liquid chromatography-mass spectrometer. Therefore, there is an urgent need to develop a small liquid chromatography-mass spectrometer based on high-precision voltage measurement.

[0007] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:

[0008] A small liquid chromatography-mass spectrometer based on high-precision voltage measurement is disclosed. The spectrometer includes a housing, with a shell bolted to the top. The shell contains a primary chamber, a secondary chamber, and a mounting area, arranged vertically. An ion funnel is located inside the primary chamber. A conical plate is bolted to the top of the inner wall of the secondary chamber, with the top of the conical plate extending into the primary chamber. An electron multiplier and a linear ion trap are located inside the secondary chamber. There are two DC lenses located at both ends of the linear ion trap. A molecular pump and a mechanical pump are respectively installed on the bottom sides of the inner wall of the placement area by bolts. The molecular pump is connected to the mechanical pump through a pipe. One end of the molecular pump is provided with a second connecting pipe, and the other end of the second connecting pipe extends into the interior of the secondary cavity. One end of the mechanical pump is provided with a first connecting pipe, and one end of the first connecting pipe extends into the interior of the primary cavity. An ultraviolet lamp is installed on one side of the outer wall of the box by bolts, and the ultraviolet lamp extends into the interior of the primary cavity. The linear ion trap is composed of two parallel planar electrode groups, and the linear ion trap is a double potential trap plane.

[0009] As a preferred embodiment of the small liquid chromatography-mass spectrometer based on high-precision voltage measurement described in this invention, wherein: a breathable grid is embedded in one side of the outer wall of the housing by bolts, and grooves are provided on both sides of the outer wall of the housing.

[0010] As a preferred embodiment of the small liquid chromatography-mass spectrometer based on high-precision voltage measurement described in this invention, wherein: one end of the mechanical pump is threadedly connected to a threaded cap, and a filter element is provided inside the threaded cap.

[0011] As a preferred embodiment of the small liquid chromatography-mass spectrometer based on high-precision voltage measurement described in this invention, a microcomputer module is installed on one side of the inner wall of the housing by bolts, and the microcomputer module is electrically connected to the mechanical pump and the molecular pump by wires respectively.

[0012] As a preferred embodiment of the small liquid chromatography-mass spectrometer based on high-precision voltage measurement described in this invention, the outer wall of the top side of the housing is fitted with a cover via a hinge, and a handle groove is provided on the outer wall of the top side of the cover.

[0013] As a preferred embodiment of the small liquid chromatography-mass spectrometer based on high-precision voltage measurement described in this invention, a feeding assembly is provided on one outer wall of the top side of the housing, and the feeding assembly is located inside the housing.

[0014] As a preferred embodiment of the small liquid chromatography-mass spectrometer based on high-precision voltage measurement described in this invention, the feeding assembly includes a liquid storage cylinder, and the liquid storage cylinder is provided with a liquid storage chamber and a water storage chamber respectively.

[0015] As a preferred embodiment of the small liquid chromatography-mass spectrometer based on high-precision voltage measurement described in this invention, the outer walls on both sides of the top of the liquid storage cylinder are threaded with threaded plugs, and the two threaded plugs extend into the liquid storage chamber and the water storage chamber, respectively.

[0016] As a preferred embodiment of the small liquid chromatography-mass spectrometer based on high-precision voltage measurement described in this invention, wherein: a pump body is threadedly connected to the outer wall of one side of the bottom of the storage cylinder, and the top of the pump body extends into the storage chamber; an inlet tube is threadedly connected to the discharge end of the pump body, and the inlet tube extends into the interior of the primary chamber.

[0017] As a preferred embodiment of the small liquid chromatography-mass spectrometer based on high-precision voltage measurement described in this invention, wherein: a solenoid valve is threadedly connected to the outer wall of one side of the bottom of the liquid storage cylinder, and the top of the solenoid valve extends into the water storage chamber; one end of the solenoid valve is provided with a water supply pipe, and the other end of the water supply pipe is connected to the pump body.

[0018] Compared with existing technologies:

[0019] The linear ion trap designed in this invention is a dual-potential-well plane, which can separately realize the collection of incoming ions and the controllable cooling and ejection of confined ions. Compared with a single-potential-well plane ion trap, the linear ion trap can collect and focus ions more effectively. At the same time, the working cycle, ion flux, and ejected ions of the dual-potential-well plane ion trap meet the working requirements of a multiple reflection time-of-flight mass spectrometer, and can be coupled with it to provide it with high-flux, state-concentrated introduced ions, which greatly improves the detection accuracy and precision of the liquid chromatography-mass spectrometer.

[0020] The feeding component designed in this invention can start the solenoid valve after the liquid chromatography-mass spectrometry analysis is completed, so that the pump body draws the clean water inside the water storage chamber into the sample inlet tube, and then the clean water repeats the flow path of the material to be detected, thereby cleaning the internal structure of the primary and secondary chambers and achieving the purpose of automatic cleaning of the liquid chromatography-mass spectrometer.

[0021] The threaded cap and filter element designed in this invention allow the extracted gas to be filtered and discharged when the mechanical pump starts to balance the pressure inside the primary and secondary chambers, thus achieving the filtration of the extracted gas and preventing the discharged gas from polluting the surrounding air environment. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 This is a schematic diagram of the back structure of the box body and box shell provided by the present invention;

[0024] Figure 3 This is a schematic diagram of the planar structure of the box body and box shell provided by the present invention;

[0025] Figure 4 This is a schematic diagram of the feeding assembly structure provided by the present invention.

[0026] Explanation of reference numerals in the attached drawings: 1. Box body; 2. Box shell; 3. Vent grille; 4. Box cover; 5. Handle groove; 6. Microcomputer module; 7. Placement area; 8. Molecular pump; 9. Mechanical pump; 10. Threaded cap; 11. Filter element; 12. Connecting pipe one; 13. Secondary chamber; 14. Linear ion trap; 15. Electron multiplier; 16. Connecting pipe two; 17. DC lens; 18. Conical plate; 19. Primary chamber; 20. Ion funnel; 21. Ultraviolet lamp; 22. Feeding assembly; 23. Liquid storage cylinder; 24. Threaded plug; 25. Liquid storage chamber; 26. Water storage chamber; 27. Solenoid valve; 28. Water supply pipe; 29. ​​Pump body; 30. Sample inlet pipe; 31. Groove. Detailed Implementation

[0027] The following will be combined with the appendix Figure 1-4 This invention will be described in detail, and the technical solutions in the embodiments of this invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] This invention provides, through improvements, a small liquid chromatography-mass spectrometer based on high-precision voltage measurement, such as... Figures 1-4As shown, the device includes a housing 1, with a shell 2 bolted to the top of the housing 1. The shell 2 contains a primary cavity 19, a secondary cavity 13, and a placement area 7, arranged vertically. The primary cavity 19, secondary cavity 13, and placement area 7 are arranged vertically. The primary cavity 19 contains an ion funnel 20, which consists of 27 annular metal electrode plates with a total length of approximately 35 mm and an electrode thickness of 0.3 mm. The electrode plate aperture gradually decreases from 8.8 mm to 1 mm. A conical plate 18 is bolted to the top of the inner wall of the secondary cavity 13, with the top of the conical plate 18 extending into the primary cavity 19. The secondary cavity 13 contains an electron multiplier 15 and a linear ion trap 14. The secondary cavity 13 also contains two... DC lenses 17 are located at both ends of the linear ion trap 14. The DC lenses 17 are planar metal electrodes, 1 mm thick, with a central aperture of 0.3 mm. The distance between them and the conical aperture and the front plate of the ion trap is 3 mm. A -30V voltage is applied in positive ion mode. Molecular pumps 8 and 9 are bolted to the bottom sides of the inner wall of the placement area 7. The preferred model for molecular pump 8 is an AGILENTTwisTorr704FS magnetic levitation molecular pump, and the preferred model for mechanical pump 9 is an AD5KEEDB12 / 24SV. During normal operation, the pressure in the primary chamber 19 is maintained within the range of 130-1300 Pa, and the pressure in the secondary chamber 13 is maintained at approximately 0.27 Pa. Molecular pumps 8 and 9 are interconnected via pipes. Pump 8 has a connecting pipe 2 16 at one end, and the other end of connecting pipe 2 16 extends into the secondary chamber 13. Mechanical pump 9 has a connecting pipe 1 12 at one end, and the other end of connecting pipe 12 extends into the primary chamber 19. An ultraviolet lamp 21 is bolted to the outer wall of one side of the housing 1. The ultraviolet lamp 21 is preferably of the LUYOR-2130L model and extends into the primary chamber 19. The linear ion trap 14 consists of two parallel planar electrode groups with a spacing of 4.2 mm, a field radius of 4 mm, and a length of 40 mm. The trap is driven by a sinusoidal frequency scanning and uses quadrupole enhanced dipole resonance excitation ion technology. The microcomputer module 6 operates the ion funnels inside the primary chamber 19 and the secondary chamber 13. 20. The ultraviolet lamp 21, electron multiplier 15, and linear ion trap 14 are started, followed by the activation of the pump 29. This allows the material to be tested inside the storage chamber 25 to flow into the ion funnel 20 through the sample inlet tube 30, and then into the DC lens 17 and linear ion trap 14 inside the secondary chamber 13 through the conical plate 18. This, combined with the activated electron multiplier 15, enables the detection of the material to be tested. During the detection process, since the linear ion trap 14 is a double potential trap plane, it can separately realize the collection of incoming ions and the controllable cooling and ejection of confined ions, meeting the working requirements of the multiple reflection time-of-flight mass spectrometer. It can also be coupled with it to provide it with high-throughput, state-concentrated introduced ions, greatly improving the detection accuracy and precision of the liquid chromatography-mass spectrometer.

[0030] Furthermore, a vent grille 3 is embedded in one side of the outer wall of the housing 1 by bolts, and grooves 31 are provided on both sides of the outer wall of the housing 1. One end of the mechanical pump 9 is threadedly connected to a threaded cover 10, and a filter element 11 is provided inside the threaded cover 10. The filter element 11 is activated carbon. When the mechanical pump 9 starts to balance the pressure inside the primary chamber 19 and the secondary chamber 13, the gas it extracts will be filtered and discharged through the filter element 11, and then discharged into the air through the vent grille 3, thereby achieving the filtration of the extracted gas and preventing the discharged gas from polluting the surrounding air environment.

[0031] Furthermore, a microcomputer module 6 is bolted to one side of the inner wall of the housing 2. The microcomputer module 6 is an industrial tablet computer. Operating the microcomputer module 6 can control the start of the electronic equipment on the device. The microcomputer module 6 is electrically connected to the mechanical pump 9 and the molecular pump 8 through wires. A cover 4 is installed on one side of the top outer wall of the housing 2 via a hinge. A handle groove 5 is opened on one side of the top outer wall of the cover 4. The cover 4 can be opened by pulling it open through the handle groove 5.

[0032] Furthermore, a feeding assembly 22 is provided on one outer wall of the top of the housing 1, and the feeding assembly 22 is located inside the housing 2. The feeding assembly 22 includes a liquid storage cylinder 23, which has a liquid storage chamber 25 and a water storage chamber 26. Threaded plugs 24 are threadedly connected to the outer walls on both sides of the top of the liquid storage cylinder 23. After unscrewing the two threaded plugs 24, the prepared material to be tested and clean water are fed into the liquid storage chamber 25 and the water storage chamber 26 for subsequent testing. The two threaded plugs 24 extend into the liquid storage chamber 25 and the water storage chamber 26, respectively. A pump body 29 is threadedly connected to one outer wall of the bottom of the liquid storage cylinder 23. The preferred model of the pump body 29 is a Kamoer 2L high-flow, high-pressure, small-volume diaphragm liquid pump KLLP1000, and the top of the pump body 29 extends into the liquid storage chamber 25. The discharge end is threadedly connected to the sample inlet tube 30, which is a capillary metal tube, 10cm long and 0.38mm inner diameter. The sample inlet tube 30 extends into the first-stage chamber 19. The bottom side of the liquid storage cylinder 23 is threadedly connected to the outer wall of the cylinder, and the top of the solenoid valve 27 extends into the water storage chamber 26. One end of the solenoid valve 27 is equipped with a water supply pipe 28. After the detection is completed, the solenoid valve 27 can be operated to start, so that the pump body 29 draws the clean water in the water storage chamber 26 into the sample inlet tube 30 through the water supply pipe 28. Then the clean water repeats the flow path of the material to be detected, thereby cleaning the internal structure of the first-stage chamber 19 and the second-stage chamber 13, avoiding cross-contamination in subsequent detections, and achieving the purpose of automatic cleaning of the liquid chromatography-mass spectrometer. The other end of the water supply pipe 28 is connected to the pump body 29.

[0033] Working Principle: When using this liquid chromatography-mass spectrometer to detect the material to be tested, the operator can open the cover 4 by pulling open the handle groove 5, and then unscrew the two threaded plugs 24. The prepared material to be tested and water are then introduced into the liquid storage chamber 25 and the water storage chamber 26, respectively. The cover 4 is then closed. The microcomputer module 6 is then activated, starting the ion funnel 20, ultraviolet lamp 21, electron multiplier 15, and linear ion trap 14 inside the primary chamber 19 and secondary chamber 13. The pump 29 is then activated, causing the material to be tested in the liquid storage chamber 25 to flow into the ion funnel 20 through the sample inlet tube 30, and then into the DC lens 17 and linear ion trap 14 inside the secondary chamber 13 through the conical plate 18. This, combined with the activated electron multiplier 15, enables the detection of the material. During the detection process, because the linear ion trap 14 is a double potential well plane, it can separately achieve the collection of incoming ions and the controlled cooling and ejection of confined ions. The system meets the operational requirements of a multiple reflection time-of-flight mass spectrometer (CFFEX) and can be coupled with it to provide high-throughput, state-concentrated introduced ions, significantly improving the detection accuracy and precision of the liquid chromatography-mass spectrometer. Simultaneously, the molecular pump 8 and mechanical pump 9 are activated during this process to regulate the internal pressure of the primary chamber 19 and secondary chamber 13. When the mechanical pump 9 starts and balances the pressure inside the primary and secondary chambers 19 and 13, the extracted gas is filtered and discharged through filter element 11, thus filtering the extracted gas and preventing pollution of the surrounding air environment. After subsequent detection, the solenoid valve 27 can be activated, causing the pump 29 to draw clean water from the water storage chamber 26 into the sample inlet tube 30. The clean water then repeats the flow path of the material to be detected, cleaning the internal structure of the primary chamber 19 and secondary chamber 13, preventing cross-contamination in subsequent detections, and achieving the automatic cleaning purpose of the liquid chromatography-mass spectrometer.

[0034] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A miniature liquid chromatography-mass spectrometer based on high-precision voltage measurement, comprising a housing (1), characterized in that: The top of the box (1) is bolted to a box shell (2). The box shell (2) contains a primary cavity (19), a secondary cavity (13), and a placement area (7). The primary cavity (19), the secondary cavity (13), and the placement area (7) are arranged in an upper and lower structure. The primary cavity (19) contains an ion funnel (20). The top of the inner wall of the secondary cavity (13) is bolted to a conical plate (18), and the top of the conical plate (18) extends into the primary cavity (19). The secondary cavity (13) contains an electron multiplier (15). The secondary cavity (13) contains a linear ion trap (14). The secondary cavity (13) contains two DC lenses (14) located at both ends of the linear ion trap (14). 7) Molecular pump (8) and mechanical pump (9) are installed on the bottom sides of the inner wall of the placement area (7) by bolts, and the molecular pump (8) is connected to the mechanical pump (9) through a pipe. One end of the molecular pump (8) is provided with a connecting pipe II (16), and the other end of the connecting pipe II (16) extends into the secondary cavity (13). One end of the mechanical pump (9) is provided with a connecting pipe I (12), and one end of the connecting pipe I (12) extends into the primary cavity (19). An ultraviolet lamp (21) is installed on one side of the outer wall of the box (1) by bolts, and the ultraviolet lamp (21) extends into the primary cavity (19). The linear ion trap (14) is composed of two parallel planar electrode groups, and the linear ion trap (14) is a double potential trap plane.

2. A miniature liquid chromatography-mass spectrometer based on high-precision voltage measurement according to claim 1, characterized in that, The outer wall of one side of the box (1) is fitted with a ventilation grille (3) by bolts, and the outer walls of both sides of the box (1) are provided with grooves (31).

3. A miniature liquid chromatography-mass spectrometer based on high-precision voltage measurement according to claim 1, characterized in that, The mechanical pump (9) is threadedly connected to a threaded cover (10) at one end, and a filter element (11) is provided inside the threaded cover (10).

4. A miniature liquid chromatography-mass spectrometer based on high-precision voltage measurement according to claim 1, characterized in that, A microcomputer module (6) is bolted to one side of the inner wall of the housing (2), and the microcomputer module (6) is electrically connected to the mechanical pump (9) and the molecular pump (8) respectively through wires.

5. A miniature liquid chromatography-mass spectrometer based on high-precision voltage measurement according to claim 1, characterized in that, The top side of the box shell (2) is fitted with a box cover (4) via a hinge, and a handle groove (5) is provided on the top side of the box cover (4).

6. A miniature liquid chromatography-mass spectrometer based on high-precision voltage measurement according to claim 1, characterized in that, The top side of the box (1) is provided with a feeding assembly (22), and the feeding assembly (22) is located inside the box shell (2).

7. A miniature liquid chromatography-mass spectrometer based on high-precision voltage measurement according to claim 6, characterized in that, The feeding assembly (22) includes a liquid storage cylinder (23), and the liquid storage cylinder (23) is provided with a liquid storage chamber (25) and a water storage chamber (26) respectively.

8. A miniature liquid chromatography-mass spectrometer based on high-precision voltage measurement according to claim 7, characterized in that, The top two outer walls of the liquid storage cylinder (23) are threaded with threaded plugs (24), and the two threaded plugs (24) extend into the liquid storage chamber (25) and the water storage chamber (26) respectively.

9. A miniature liquid chromatography-mass spectrometer based on high-precision voltage measurement according to claim 7, characterized in that, The bottom side of the liquid storage cylinder (23) is threaded with a pump body (29), and the top of the pump body (29) extends into the liquid storage chamber (25). The discharge end of the pump body (29) is threaded with an inlet tube (30), and the inlet tube (30) extends into the first-level chamber (19).

10. A miniature liquid chromatography-mass spectrometer based on high-precision voltage measurement according to claim 7, characterized in that, The bottom side of the liquid storage cylinder (23) is threaded with a solenoid valve (27), and the top of the solenoid valve (27) extends into the water storage chamber (26). One end of the solenoid valve (27) is provided with a water supply pipe (28), and the other end of the water supply pipe (28) is connected to the pump body (29).

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