Mass spectrum detection system and electrostatic field reflector device thereof

Abstract

The utility model discloses a mass spectrum detection system and electrostatic field reflector device thereof, the electrostatic field reflector device comprises a reflector body, the reflector body comprises a plurality of electrode lenses which are coaxially arranged, and a gap is arranged between two adjacent electrode lenses; the electrode lens comprises a cylindrical electrode arranged in the axial direction and an annular electrode arranged in the radial direction, and the cylindrical electrode and the annular electrode are arranged into a whole; a voltage dividing unit is arranged between every two adjacent electrode lenses, and each voltage dividing unit is in conductive connection with the corresponding two adjacent electrode lenses. According to the utility model, the electrostatic field reflector device is provided with the plurality of electrode lenses which are coaxially arranged, the electrode lenses are provided with the cylindrical electrodes located in the axial direction and the annular electrodes located in the radial direction, and the cylindrical electrodes and the annular electrodes are arranged into a whole. The electrostatic field generated by each electrode lens can extend in the axial direction and the radial direction, and after the electrostatic fields of the plurality of electrode lenses are combined, an electrostatic field with stable and uniform electric potential can be formed in the electrostatic field reflector device.

Description

Technical Field

[0001] This utility model belongs to the field of mass spectrometry measurement technology, specifically a mass spectrometry detection system and its electrostatic field reflector device. Background Technology

[0002] Time-of-flight mass spectrometry (TOF-MS) is a commonly used mass spectrometer. Its mass analyzer is an ion drift tube. Ions generated by the ion source are accelerated and enter a field-free tube, traveling at a constant velocity towards the ion receiver. The larger the ion mass, the longer it takes to reach the receiver; conversely, the smaller the ion mass, the shorter the time. Based on this principle, ions of different masses can be separated according to their m / z values. TOF-MS has a wide detectable molecular weight range, fast scanning speed, and a simple instrument structure.

[0003] The main drawback of time-of-flight mass spectrometers is their low resolution. This is because ions leave the ion source with varying initial energies, resulting in a distribution in the time it takes for ions with the same mass-to-charge ratio to reach the detector, thus reducing resolution. One improvement method is to add a set of electrostatic field mirrors. These mirrors push the freely flying ions back towards the ion detector. Ions with higher initial energies travel a longer distance into the electrostatic field mirrors due to their faster initial velocity, resulting in a longer return journey. Ions with lower initial energies travel a shorter return journey, thus focusing them at a certain point along their return path and improving the instrument's resolution.

[0004] In the prior art, the electrostatic field reflector consists of multiple coaxially arranged annular electrode plates, with adjacent annular electrode plates separated by support columns. Although an electrostatic field can be formed, the distribution of the electrostatic field is uneven and the potential is unstable, which causes the ions to be subjected to unstable forces within the electrostatic field reflector, resulting in a decrease in resolution. Utility Model Content

[0005] In view of this, in order to overcome the shortcomings of the existing technology, the purpose of this utility model is to provide a mass spectrometry detection system and its electrostatic field reflector device.

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

[0007] This invention first proposes an electrostatic field reflector device, including a reflector body, the reflector body including a plurality of electrode lenses arranged coaxially, with a gap between two adjacent electrode lenses; each electrode lens includes a cylindrical electrode arranged in the axial direction and an annular electrode arranged in the radial direction; a voltage dividing unit for voltage division to make the electric field uniformly distributed is provided between two adjacent electrode lenses, and the voltage dividing unit is electrically connected to the two adjacent electrode lenses.

[0008] Furthermore, the cylindrical electrode and the annular electrode are integrated; the inner diameter of the annular electrode is smaller than the inner diameter of the cylindrical electrode, and the outer diameter of the annular electrode is larger than the outer diameter of the cylindrical electrode.

[0009] The annular electrode is located at one end of the cylindrical electrode, or the annular electrode is located in the middle of the cylindrical electrode.

[0010] Furthermore, a lens shielding mesh assembly is provided at one end of the reflector body; the lens shielding mesh assembly includes a lens shielding mesh and a shielding mesh cover plate for fixing the lens shielding mesh to the reflector body.

[0011] Furthermore, the voltage divider unit includes a resistor; and / or, the reflector body further includes at least two positioning rods for positioning the electrode lens, and the annular electrode is provided with positioning holes corresponding to the positioning rods, and the annular electrode is sleeved on the positioning rods through the positioning holes.

[0012] Furthermore, the positioning rod is fitted with an isolation sleeve located between two adjacent annular electrodes and at one end of the reflector body.

[0013] Furthermore, each end of the isolation sleeve is provided with a positioning slot and a positioning plug. In two adjacent isolation sleeves, the positioning plug of one isolation sleeve passes through the positioning hole and is inserted into the positioning slot of the other isolation sleeve.

[0014] Furthermore, the reflector body also includes a connector, on which a resistor plate is mounted, and the resistor is mounted on the resistor plate.

[0015] Furthermore, there are two connectors, which are respectively mounted on the two electrode lenses located at both ends, and the resistor plate is mounted between the two connectors.

[0016] Furthermore, the annular electrode is provided with a connecting portion, and the resistor is connected to the corresponding annular electrode through the resistor plate.

[0017] This invention also proposes a mass spectrometry detection system, including a flight tube, wherein an electrostatic field reflector device as described above is installed inside the flight tube.

[0018] The beneficial effects of this utility model are as follows:

[0019] The electrostatic field reflector device of this invention is configured as a plurality of coaxially arranged electrode lenses, with the electrode lenses being cylindrical electrodes in the axial direction and annular electrodes in the radial direction. In this way, the electrostatic field generated by each electrode lens can extend in both the axial and radial directions. After the electrostatic fields of multiple electrode lenses are combined, a stable and uniform electrostatic field can be formed inside the electrostatic field reflector device. Attached Figure Description

[0020] To make the objectives, technical solutions, and beneficial effects of this utility model clearer, the following drawings are provided for illustration:

[0021] Figure 1 This is a schematic diagram of the structure of an embodiment of the electrostatic field reflector device of this utility model;

[0022] Figure 2 This is an axonometric view of the electrostatic field reflector device;

[0023] Figure 3 This is a structural diagram of a cross-shaped electrode lens;

[0024] Figure 4 A schematic diagram of the electric field of an electrostatic field reflector device using a cross-shaped electrode lens;

[0025] Figure 5 A simulation diagram of ion trajectories using an electrostatic field reflector device with a cross-shaped electrode lens;

[0026] Figure 6 This is a structural diagram of a T-shaped electrode lens;

[0027] Figure 7 A schematic diagram of the electric field of an electrostatic field reflector device using a T-shaped electrode lens;

[0028] Figure 8 A simulation diagram of ion trajectories using an electrostatic field reflector device with a T-shaped electrode lens;

[0029] Figure 9 This is a schematic diagram of the mass spectrometry detection system using the electrostatic field reflector device of this embodiment;

[0030] Figure 10 This is a cross-sectional view of a mass spectrometry detection system;

[0031] Figure 11 for Figure 10 Exploded view;

[0032] Figure 12 This is a schematic diagram of the reflection detector module;

[0033] Figure 13 This is an exploded view of the reflection detector module;

[0034] Figure 14 for Figure 13 Axonometric view.

[0035] 10-Flight tube; 11-Transfer pipe; 12-First shielding mesh; 13-Mounting base;

[0036] 20-Linear detector module;

[0037] 30-Reflection detector module; 31-Housing; 32-Second shielding mesh; 33-Shielding mesh cover; 331-Through hole; 34-Detector base; 35-Microchannel plate; 36-Conductive sheet; 37-Limiting sheet; 38-First voltage divider plate; 39-Signal board; 40-Flexible board; 41-Second voltage divider plate; 42-Signal connector; 43-Conductive screw; 44-Insulating sleeve; 45-Step screw; 46-Compression spring; 47-Screw; 48-Screw;

[0038] 50-Reflector body; 51-Electrode lens; 511-Cylindrical electrode; 512-Annular electrode; 513-Connector; 52-Gap; 53-Resistor; 54-Positioning rod; 55-Isolation sleeve; 551-Positioning slot; 552-Positioning plug; 56-Lens shielding mesh; 57-Shielding mesh cover; 58-Connector base; 59-Resistor plate;

[0039] 60 - Shielding tube; 61 - Repulsion module. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0041] like Figure 1-2 As shown, the electrostatic field reflector device includes a reflector body 50, which includes a plurality of electrode lenses 51 coaxially arranged, with a gap 52 between adjacent electrode lenses 51. Each electrode lens 51 includes a cylindrical electrode 511 arranged along the axial direction and an annular electrode 512 arranged along the radial direction. A voltage dividing unit is provided between adjacent electrode lenses 51 for voltage division to achieve a uniform electric field distribution (for example, this voltage dividing unit may include, but is not limited to, a resistor 53; for ease of understanding and description, a resistor 53 is used as an example for the following description). The resistor 53 is electrically connected to the two adjacent electrode lenses 51. In this embodiment, the annular electrode 512 is provided with a connection portion 513 for connecting to the resistor 53.

[0042] The reflector body 50 of this embodiment also includes at least two positioning rods 54 for positioning the electrode lens 51. The annular electrode 512 has positioning holes corresponding to the positioning rods 54, and the annular electrode 512 is sleeved on the positioning rod 54 through the positioning holes. In this embodiment, three positioning rods 54 are evenly distributed in a ring. Isolation sleeves 55 are sleeved on the positioning rods 54, located between two adjacent annular electrodes 512 and at one end of the reflector body 50. In this embodiment, the two ends of the isolation sleeve 55 are respectively provided with positioning slots 551 and positioning plugs 552. In two adjacent isolation sleeves 55, the positioning plug 552 of one isolation sleeve 55 passes through the positioning hole and engages with the positioning slot 551 of the other isolation sleeve 55.

[0043] In one embodiment of this invention, a lens shielding mesh assembly is provided at one end of the reflector body 50. The lens shielding mesh assembly of this embodiment includes a lens shielding mesh 56 and a shielding mesh cover plate 57 for fixing the lens shielding mesh 56 to the electrostatic field reflector device.

[0044] In one embodiment of this invention, the reflector body 50 further includes a connecting base 58, on which a resistor plate 59 is mounted. A resistor 53 is mounted on the resistor plate 59 and connected to a corresponding annular electrode 512 via the resistor plate 59. The resistor 53 is locked to the corresponding annular electrode 512 via the resistor plate 59. Compared to the existing method of welding the resistor 53 to the annular electrode 512, not only is the installation of the resistor 53 more convenient, but the voltage division effect is also more reliable. In this embodiment, two connecting bases 58 are provided and respectively mounted on two electrode lenses 511 located at both ends, and the resistor plate 59 is mounted between the two connecting bases 58.

[0045] In this embodiment, the cylindrical electrode 511 and the annular electrode 512 are integrated. The inner diameter d1 of the annular electrode 512 is smaller than the inner diameter D1 of the cylindrical electrode 511, and the outer diameter d2 of the annular electrode 512 is larger than the outer diameter D2 of the cylindrical electrode 511. Specifically, in some embodiments, the annular electrode 512 may be located in the middle of the cylindrical electrode 511 (hereinafter referred to as the "cross-shaped electrode lens"), such as... Figure 3 As shown. In other embodiments, the annular electrode 512 can be located at one end of the cylindrical electrode 511 (hereinafter referred to as the "T-shaped electrode lens"), such as... Figure 6 As shown.

[0046] The function of an electrostatic field reflector is to deflect freely flying ions back. When ions reach the reflector, those with higher initial energy travel a longer distance into the electrostatic field due to their higher initial velocity, resulting in a longer return journey. Ions with lower initial energy travel a shorter return journey, thus focusing at a certain point along their return path, thereby improving the instrument's resolving power. COMSOL simulations reveal that under the same conditions (20000V for the first-stage lens, with voltage decreasing progressively), the electric field lines of an electrostatic field reflector using a T-shaped electrode lens (e.g., ...) Figure 4 (as shown) and the electric field lines of the electrostatic field reflector device using a cross-shaped electrode lens (as shown) Figure 7 Compared to the T-shaped reflector device shown below, the electric field lines at the edge of the channel near the center are more curved. A comparison of the potentials at six points (three at the center and three at the edges) is shown in Table 1.

[0047] Table 1 Comparison of potentials for T-shaped and cross-shaped reflector devices

[0048]

[0049] like Figure 5 The diagram shown is a simulation of the ion trajectory of an electrostatic field reflector device using a cross-shaped electrode lens. Figure 8 The diagram shown is a simulation of the ion trajectory of an electrostatic field reflector device using a T-shaped electrode lens. The cross-shaped lens assembly has a more stable potential and a more uniform electric field at the same height than the T-shaped lens assembly, and thus has a relatively smaller impact on the ion flight path and energy. Therefore, in this embodiment, the annular electrode 512 is preferably located in the middle of the cylindrical electrode 511 (hereinafter referred to as the "cross-shaped electrode lens").

[0050] This embodiment also proposes a coaxial analyzer for a mass spectrometer, including a flight tube 10, within which an electrostatic field reflector device as described above is installed. Specifically, as shown... Figure 9-11 As shown, the coaxial analyzer of the mass spectrometer in this embodiment includes a flight tube 10, a reflection detector module 30, and an electrostatic field mirror device, wherein the reflector body 50 of the electrostatic field mirror device is disposed inside the flight tube 10. Specifically, the flight tube 10 is used to provide a vacuum and field-free environment for ion flight; the reflection detector module 30 is used to convert the received ions into electrical signals after multiplication in reflection mode; the electrostatic field mirror device is used to form a reverse electric field and reverse the ions to the reflection detector module. In this embodiment, the reflection detector module 30 is disposed at the first end of the flight tube 10, and the electrostatic field mirror device is disposed inside the flight tube 10. Both the reflection detector module 30 and the electrostatic field mirror device are coaxially arranged with the flight tube 10, and the reflection detector module 30 is provided with a shielding tube 60 for allowing ions to enter the flight tube 10.

[0051] By setting a reflection detector module 30 at the first end of the flight tube 10 and an electrostatic field reflector device inside the flight tube 10, the coaxial analyzer of the mass spectrometer in this embodiment can perform reflection mode measurements. Specifically, when performing reflection mode measurements, the electrostatic field reflector device is energized. Ions are excited by the ion source and enter the flight tube 10 from the shielding tube 60. After entering the electrostatic field reflector device, the electromagnetic force exerted by the electrostatic field on the ions causes them to deflect, pushing them back to the reflection detector module 30. The ions received by the reflection detector module 30 are multiplied and converted into an electrical signal.

[0052] In a preferred embodiment of this example, the coaxial analyzer of the mass spectrometer further includes a linear detector module 20. The linear detector module 20 is used to multiply the received ions and convert them into an electrical signal in linear mode. Specifically, the linear detector module 20 is disposed at the second end of the flight tube 10, and is coaxially arranged with the flight tube 10. By disposing of the linear detector module 20 at the second end of the flight tube 10, linear mode measurements can be performed. Specifically, when performing linear mode measurements, the power supply to the electrostatic field reflector is cut off. After ions are excited by the ion source, they enter the flight tube 10 from the shielding tube 60 and directly reach the linear detector module 20, which multiplies the received ions and converts them into an electrical signal.

[0053] In one embodiment of this invention, a transfer tube 11 is installed at the first end of the flight tube 10, and a reflection detector module 30 is installed on the transfer tube 11. A first shielding mesh 12 is installed on the transfer tube 11, and the first shielding mesh 12 is used to shield external electromagnetic fields. The reflection detector module 30 is located between the first shielding mesh 12 and the flight tube 10.

[0054] In one embodiment of this invention, a repulsion module 61 is provided at the entrance of the shielding tube 60. The repulsion module 61 is used to generate an electric field perpendicular to the ion flight direction to achieve ion screening. Specifically, before and / or after the desired ions arrive, the repulsion module 61 is energized, causing unwanted ions to deflect under the electric field applied by the repulsion module 61, preventing these ions from entering the reflection detector module 30 or the linear detector module 20. In this embodiment, by providing the repulsion module 61 at the entrance of the shielding tube, the coaxial analyzer of the mass spectrometer in this embodiment can be applied to microbial identification. Specifically, in microbial identification, interference arises from the matrix generating a large number of small molecule interfering ions, which the repulsion module can exclude. When using the reflection mode, it may be necessary to detect small molecule ions; if the repulsion module 61 is used, the desired ions will also be excluded, affecting the identification results. In this embodiment, the repulsion module 61 is positioned upstream of the reflection detector module 30 to avoid interfering with the ions that complete the reflection process. It forms a single module with the reflection detector module 30 and is coaxially arranged. This avoids the problem of repelled ions impacting the reflection detector module 30 and affecting its lifespan or causing contamination when the modules are separated or not aligned. In this process, the repulsion module 61 is located upstream of the reflection detector module 30, and the reflection detector module 30, linear detector module 20, and flight tube 10 are coaxial. The reflection detector module 30 and the repulsion module 61 are modularly designed as a whole; all three are indispensable and provide the basic conditions for their arrangement (for example, if they are not aligned, the reflection detector module 30 and the repulsion module 61 cannot form a single module). For the repulsion module 61 itself, this structure also avoids the influence of high-voltage electric fields and prevents the electric field of the repulsion module 61 from affecting the field-free flight region.

[0055] Specifically, due to the presence of the reflection detector module 30 and / or the repulsion module 61, there may be electrode interference with ion flight. By setting the first shielding mesh 12 and the shielding tube 60, the interference of the reflection detector module 30 and / or the repulsion module 61 on ion flight can be avoided.

[0056] In one embodiment of this invention, the second end of the flight tube 10 is provided with a mounting base 13. The electrostatic field reflector device and the linear detector module 20 are respectively mounted on the mounting base 13, and the electrostatic field reflector device is located between the reflection detector module 30 and the linear detector module 20. Similarly, the mounting base 13 is mainly used for mounting and fixing the reflection detector module 30 and the linear detector module 20. At the same time, the mounting base 13 is detachable to facilitate the inspection and maintenance of the reflection detector module 30 and the linear detector module 20.

[0057] like Figure 12-14As shown, the reflection detector module 30 of this embodiment includes a housing 31 and a detector assembly disposed in the housing, the detector assembly being sleeved on the shielding tube 60. The detector assembly in this embodiment has a shielding mesh assembly mounted on the housing 31 at one end facing the flight tube; the outlet of the shielding tube 60 is located close to the shielding mesh assembly, or the outlet of the shielding tube 60 abuts against the shielding mesh assembly.

[0058] In one embodiment of this invention, the shielding mesh assembly includes a second shielding mesh 32 covering the outer shell 31 and a shielding mesh cover 33 for fixing the second shielding mesh 32 to the outer shell 31. The second shielding mesh 32 is electrically grounded to the outer shell 31. The shielding mesh cover 33 is provided with a through hole 331 for ion entry and exit. The outlet of the shielding tube 60 is positioned opposite the through hole 331.

[0059] In one embodiment of this invention, the detector assembly includes a detector base 34 for providing an insulating environment, and a microchannel plate 35 for ion multiplication is installed within the detector base 34. In this embodiment, a conductive sheet 36 is provided on the side of the microchannel plate 35 facing the shielding mesh assembly to provide power to the microchannel plate 35. A limiting sheet 37 for limiting the installation of the microchannel plate 35 is provided between the conductive sheet 36 and the microchannel plate 35. A first voltage divider plate 38 for providing voltage division to the microchannel plate 35 is provided between the limiting sheet 37 and the microchannel plate 35. In this embodiment, a signal plate 39 for transmitting electrical signals is provided on the side of the microchannel plate 35 facing away from the shielding mesh assembly. A flexible plate 40 for converting multiplied ions into electrical signals is provided between the signal plate 39 and the microchannel plate 35. A second voltage divider plate 41 for dividing the voltage of the microchannel plate 35 is provided between the flexible plate 40 and the microchannel plate 35. Specifically, a signal connector 42 connected to the signal plate 39 is installed on the detector base 34. The detector base 34 is equipped with conductive screws 43 for providing power to the microchannel plate 35. Insulating sleeves 44 are fitted onto the conductive screws 43 to prevent short circuits due to insufficient insulation between the conductive screws 43 and the housing 31. In a preferred embodiment, stepped screws 45 are evenly distributed in a ring between the housing 31 and the detector base 34. Compression springs 46 are fitted onto the stepped screws 45 to provide pre-tightening force for the detector assembly. The signal board 39 in this embodiment is equipped with screws 47 for connecting and fixing the microchannel plate 35, and the housing 31 in this embodiment is equipped with screws 48 for connecting to the detector base 34.

[0060] This embodiment also proposes a mass spectrometer, which includes an ion source and a coaxial analyzer as described above. The ion source is used to excite the sample to be tested into charged particles, and the ion source is located at the first end of the flight tube 10.

[0061] This embodiment also proposes a MALDI-TOF mass spectrometer, including a laser, an acceleration module, a sample carrier module, and a coaxial analyzer. The sample carrier module is used to carry the sample and matrix, the laser is used to excite the sample to be tested into charged particles, and the acceleration module is used to accelerate the charged particles before they enter the coaxial analyzer for analysis.

[0062] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. An electrostatic field mirror device, characterized by: The device includes a reflector body, which includes a plurality of electrode lenses arranged coaxially, with a gap between adjacent electrode lenses; each electrode lens includes a cylindrical electrode arranged in the axial direction and an annular electrode arranged in the radial direction; a voltage dividing unit is provided between adjacent electrode lenses for voltage division to make the electric field uniformly distributed, and the voltage dividing unit is electrically connected to the two adjacent electrode lenses.

2. The electrostatic field mirror apparatus of claim 1, wherein: The cylindrical electrode and the annular electrode are integrated; the inner diameter of the annular electrode is smaller than the inner diameter of the cylindrical electrode, and the outer diameter of the annular electrode is larger than the outer diameter of the cylindrical electrode; the annular electrode is located at one end of the cylindrical electrode, or the annular electrode is located in the middle of the cylindrical electrode.

3. The electrostatic field mirror apparatus of claim 1, wherein: One end of the reflector body is provided with a lens shielding mesh assembly; the lens shielding mesh assembly includes a lens shielding mesh and a shielding mesh cover plate for fixing the lens shielding mesh to the reflector body.

4. The electrostatic field mirror apparatus of any of claims 1-3, wherein: The voltage divider unit includes a resistor; and / or, the reflector body further includes at least two positioning rods for positioning the electrode lens, and the annular electrode is provided with positioning holes corresponding to the positioning rods, and the annular electrode is sleeved on the positioning rods through the positioning holes.

5. The electrostatic field mirror apparatus of claim 4, wherein: The positioning rod is fitted with an isolation sleeve located between two adjacent annular electrodes and at one end of the reflector body.

6. The electrostatic field mirror apparatus of claim 5, wherein: The isolation sleeve is provided with a positioning slot and a positioning plug at both ends. In two adjacent isolation sleeves, the positioning plug of one isolation sleeve passes through the positioning hole and is inserted into the positioning slot of the other isolation sleeve.

7. The electrostatic field mirror apparatus of any of claims 1-3, wherein: The reflector body also includes a connector, on which a resistor plate is mounted, and the resistor is mounted on the resistor plate.

8. The electrostatic field mirror apparatus of claim 7, wherein: The connector is provided as two and is respectively installed on the two electrode lenses located at both ends, and the resistor plate is installed between the two connectors.

9. The electrostatic field mirror apparatus of claim 7, wherein: The annular electrode is provided with a connection part, and the resistor is connected to the corresponding annular electrode through the resistor plate.

10. A mass spectrometry detection system characterized by: It includes a flight tube, wherein an electrostatic field reflector device as described in any one of claims 1-9 is installed inside the flight tube.

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