Ion detection system and detection method

Abstract

The invention discloses an ion detection system and method, the detection system comprises a quadrupole rod emergent lens, a first deflection lens, a second deflection lens, a first dynode and a second dynode, the quadrupole rod emergent lens is configured to focus and output ions generated by a mass spectrometer; the first dynode is accommodated in the first insulating sleeve, the second dynode is accommodated in the second insulating sleeve, and both the first insulating sleeve and the second insulating sleeve are provided with openings; the first deflection lens and the second deflection lens are symmetrically arranged on the two sides of an exit port of the quadrupole rod exit lens, and the path of ions output by the quadrupole rod exit lens is changed by applying an electric field, so that positive ions deviate from the second deflection lens and reach the first dynode through the opening. And the negative ions deviate from the second deflection lens and reach the second dynode through the opening. According to the invention, simultaneous detection of positive and negative ions is realized, and the problems of low detection efficiency and poor detection precision caused by voltage switching delay are solved.

Description

Technical Field

[0001] The present invention relates to the field of mass spectrometry, and in particular to an ion detection system and a detection method. Background Art

[0002] Mass spectrometry is an analytical technique that infers the mass of ions by measuring their behavior in electric and / or magnetic fields. The core of mass spectrometry is to ionize the sample and then separate the ions according to their mass-to-charge ratio (m / z) through the action of an electric or magnetic field.

[0003] Traditional ion detection technology, such as Chinese patent publication number CN103745906A, discloses an ion measuring device that controls an isolated pulse power supply to connect a positive power interface or a negative power interface as needed, thereby realizing switching detection of positive and negative ions.

[0004] Considering that the number of ions separated by mass-to-charge ratio that reach the detector is very limited, a high energy conversion dynode 200 is usually used, such as Figure 1 As shown, when receiving ions passing through the quadrupole exit lens 100, the analyte ions from the mass spectrometer collide with the surface of the dynode 200, a charge exchange process occurs and the ions are converted into electrons, and then these electrons are input into the electron multiplier 300 for further amplification, thereby improving the sensitivity of the detection. Typically, when it is necessary to detect positive and negative ions, the dynode needs to switch the voltage, that is, switch between a positive high voltage and a negative high voltage. The volt value of the high voltage usually reaches more than 8000 volts, or even as high as 15000 volts. The high voltage electric energy converts the ions into stronger electrical signals, especially for ions with a small sample amount, so as to improve the sensitivity. However, for the high voltage module, the voltage switching generally takes 20 to 30 ms, and in order to stabilize the signal, a certain delay needs to be set. Therefore, the positive and negative ion switching process usually loses 50 to 100 ms of ions. The ions lost due to the positive and negative ion switching not only reduce the detection efficiency, but also significantly affect the detection accuracy of the system.

[0005] The disclosure of the above background technology content is only used to assist in understanding the concept and technical solution of the present application. It does not necessarily belong to the prior art of the present application, nor does it necessarily provide technical guidance. In the absence of clear evidence that the above content has been disclosed before the filing date of the present application, the above background technology should not be used to evaluate the novelty and creativity of the present application. Summary of the invention

[0006] The purpose of the present invention is to provide a system for simultaneously detecting positive and negative ions without switching the positive and negative high voltages of the dynode, thereby solving the problem of low detection efficiency and poor detection accuracy caused by voltage switching delay.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows: An ion detection system comprises a quadrupole exit lens, a first deflection lens, a second deflection lens, a first dynode and a second dynode, wherein the quadrupole exit lens is configured to focus and output ions generated by a mass spectrometer; The first dynode is accommodated in a first insulating sleeve, and a first opening is provided on the first insulating sleeve; the second dynode is accommodated in a second insulating sleeve, and a second opening is provided on the second insulating sleeve; The first deflection lens and the second deflection lens are symmetrically arranged on both sides of the exit port of the quadrupole exit lens, and the paths of ions output by the quadrupole exit lens are changed by applying an electric field, so that positive ions pass through the first opening along a first path deviating from the second deflection lens and reach the first dynode, and negative ions pass through the second opening along a second path deviating from the first deflection lens and reach the second dynode.

[0008] Further, based on any one of the technical solutions or a combination of multiple technical solutions described above, the first deflection lens and the second deflection lens are both strip-shaped, and their axes in the length direction are parallel to the exit surface of the quadrupole exit lens.

[0009] Further, based on any one of the above-mentioned technical solutions or a combination of multiple technical solutions, the width of the gap between the first deflection lens and the exit surface of the quadrupole exit lens ranges from 5 to 10 mm; The width of the gap between the second deflecting lens and the exit surface of the quadrupole exit lens ranges from 5 to 10 mm.

[0010] Further, based on any one of the technical solutions or a combination of multiple technical solutions mentioned above, the distance between the first deflection lens and the second deflection lens ranges from 10 to 15 mm.

[0011] Further, based on any one of the technical solutions or a combination of multiple technical solutions described above, the first dynode and the second dynode are symmetrically arranged on both sides of the exit port of the quadrupole exit lens, and the impacted surfaces of the first dynode and the second dynode are perpendicular to the exit surface of the quadrupole exit lens.

[0012] Further, based on any one of the above-mentioned technical solutions or a combination of multiple technical solutions, the distance between the impacted area of ​​the first dynode and the exit surface of the quadrupole exit lens ranges from 18 to 25 mm; The distance between the impacted area of ​​the second dynode and the exit surface of the quadrupole exit lens ranges from 18 to 25 mm.

[0013] Further, based on any one of the above-mentioned technical solutions or a combination of multiple technical solutions, the distance between the impacted area of ​​the first dynode and the impacted area of ​​the second dynode is in the range of 40 to 80 mm.

[0014] Further, based on any one of the technical solutions or a combination of multiple technical solutions mentioned above, the ion detection system provided by the present invention also includes an electron multiplier, which is configured to receive ions transmitted from the first dynode and the second dynode.

[0015] Further, based on any one of the above-mentioned technical solutions or a combination of multiple technical solutions, the ion detection system provided by the present invention also includes a first electron multiplier and a second electron multiplier, wherein the first electron multiplier is arranged in the first insulating sleeve and is configured to receive ions transmitted from the first dynode; The second electron multiplier is disposed in the second insulating sleeve and is configured to receive ions transferred from the second dynode.

[0016] According to another aspect of the present invention, there is provided an ion detection method, comprising the following steps: The ions generated by the mass spectrometer are focused and output using the quadrupole exit lens; Using two deflection lenses to apply an electric field to the ions output by the quadrupole output lens to separate positive ions from negative ions; The separated positive ions hit the first dynode, and the separated negative ions hit the second dynode, and the generated electrons are transferred to the electron multiplier; The signal board is used to collect and process the electrical signal output by the electron multiplier, and the signal is converted into the detection value of the ion according to the processing result of the signal board.

[0017] Further, based on any one of the above technical solutions or a combination of multiple technical solutions, the electric field is applied in the following manner: Applying a negative voltage -V to the first deflection lens and applying a positive voltage V to the second deflection lens; Determine a voltage amplitude range V∈[Vmin,Vmax], which satisfies that the region where the ions impact the dynode is within a preset region; The voltage applied to the first deflecting lens and the second deflecting lens is dynamically changed within the voltage amplitude range.

[0018] The beneficial effects brought by the technical solution provided by the present invention are as follows: a. By constructing a suitable electric field through the ion optical system, positive and negative ions are separated and transmitted to the corresponding dynodes, avoiding the switching of high voltage on the dynodes. Since the two dynodes are always maintained at their respective fixed high voltage states, theoretically no ion loss will occur, thus switching between positive and negative ion detection can be performed more quickly, reducing ion loss and improving the signal-to-noise ratio; b. The ion detection system can detect positive and negative ions at the same time, improving detection efficiency; c. The design of the insulating sleeve can reduce the impact of the electric field generated by the high voltage applied to the dynode on the movement trajectory of ions before impact, and accurately control the deflection angle of the ions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 This is a schematic diagram of a typical device structure for realizing ion detection by switching the positive and negative high voltages of the dynode; Figure 2 A schematic diagram of a system structure for simultaneous detection of positive and negative ions provided by an exemplary embodiment of the present invention; Figure 3 for Figure 2 Schematic diagram of ion trajectories in the middle insulating sleeve; Figure 4 A schematic diagram of an ion transmission path of an ion detection system provided for an exemplary embodiment of the present invention; Figure 5 A schematic diagram of a detection system having only one electron multiplier provided for an exemplary embodiment of the present invention; Figure 6 A side view of a detection system for eliminating a deflection lens structure provided for the first comparative example; Figure 7 A side view of the ion detection system after the distance parameter is changed for the second comparative example; Figure 8 A schematic flow chart of an ion detection method provided for an exemplary embodiment of the present invention.

[0021] Among them, the figure marks include: 100-quadrupole output lens, 200-dynode, 210-first dynode, 220-second dynode, 300-electron multiplier, 310-first electron multiplier, 320-second electron multiplier, 410-first deflection lens, 420-second deflection lens, 510-first insulating sleeve, 512-first opening, 520-second insulating sleeve, 522-second opening. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, device, product or equipment that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0024] In one embodiment of the present invention, an ion detection system is provided, such as Figure 2 and Figure 4 As shown, the detection system includes a quadrupole exit lens 100, a first deflection lens 410, a second deflection lens 420, a first dynode 210, and a second dynode 220, wherein the quadrupole exit lens 100 is configured to focus and output ions generated by the mass spectrometer, and specifically, the quadrupole exit lens 100 is located behind the quadrupole. By applying appropriate voltages, the quadrupole exit lens 100 focuses the ions into a beam, and introduces the ions output from the quadrupole (field) into the detection system.

[0025] like Figure 2As shown, the first dynode 210 is accommodated in the first insulating sleeve 510, and the first insulating sleeve 510 is provided with a first opening 512; the second dynode 220 is accommodated in the second insulating sleeve 520, and the second insulating sleeve 520 is provided with a second opening 522; the first dynode 210 and the second dynode 220 are high energy conversion dynodes, referred to as HECD. The first insulating sleeve 510 and the second insulating sleeve 520 are made of insulating materials, such as ceramics, polytetrafluoroethylene, etc. The first dynode 210 and the second dynode 220 are made of metal materials, such as stainless steel, copper, etc., and the impacted surface thereof can be a plane.

[0026] like Figure 2 As shown, the first deflection lens 410 and the second deflection lens 420 are both strip-shaped, and the first deflection lens 410 and the second deflection lens 420 are symmetrically arranged on both sides of the exit port of the quadrupole exit lens 100, and their longitudinal axes are parallel to the exit surface of the quadrupole exit lens 100.

[0027] The first deflection lens 410 and the second deflection lens 420 apply an electric field, so that the ions output from the quadrupole output lens 100 are affected by the electric field and the transmission path is changed, such as Figure 4 As shown; specifically, the force direction of positive ions in the electric field is the same as the direction of the electric field, that is, the first deflection lens 410 applied with a negative voltage will attract positive ions, and the second deflection lens 420 applied with a positive voltage will repel positive ions, so that the positive ions pass through the first opening 512 along a first path deviating from the second deflection lens 420 and reach the first dynode 210, and that is, the first deflection lens 410 applied with a negative voltage will repel negative ions, and the second deflection lens 420 applied with a positive voltage will attract positive ions, so that the negative ions pass through the second opening 522 along a second path deviating from the first deflection lens 410 and reach the second dynode 220, as shown Figure 3 shown.

[0028] The first dynode 210 and the second dynode 220 are symmetrically arranged on both sides of the exit port of the quadrupole exit lens 100. Figure 4As shown, the impacted surfaces of the first dynode 210 and the second dynode 220 are perpendicular to the exit surface of the quadrupole exit lens 100. The ion detection system also includes an electron multiplier, which is configured to receive ions transmitted from the first dynode 210 and / or the second dynode 220. The electrons generated by the ions impacting the dynode surface are further amplified by the electron multiplier to form a measurable electrical signal. In a specific embodiment, the electron multiplier includes a multi-stage dynode, and a certain voltage is applied between each stage of the dynode, so that the ions generate electrons when they impact the dynode, and these electrons impact the next stage of the dynode again to generate more electrons, thereby achieving signal amplification. The output end of the electron multiplier is connected to a signal board, and the signal board is used to collect and process the electrical signal output by the electron multiplier, and convert it into the detection value of the ion according to the processing result of the signal board.

[0029] by Figure 2 and Figure 4 Taking the direction shown as an example: the ions emitted from left to right enter the electric field between the first deflection lens 410 and the second deflection lens 420, and the positive and negative ions are offset and separated: the positive ions move upward and forward until they hit the rear surface of the first dynode 210. After the collision, the ions leave the first dynode 210 and then enter the electron multiplier backward. They collide in the path of moving upward and forward, and will not cause the ions before the collision with the first dynode 210 to interfere with the electrons leaving the first dynode 210 after the collision. Similarly, the negative ions move downward and forward until they hit the rear surface of the second dynode 220. After the collision, the electrons leave the second dynode 220 and then enter the electron multiplier backward. They collide in the path of moving downward and forward, and will not cause the ions before the collision with the second dynode 220 to interfere with the electrons leaving the second dynode 220 after the device.

[0030] like Figure 2 As shown, there are two electron multipliers, including a first electron multiplier 310 and a second electron multiplier 320, wherein the first electron multiplier 310 is disposed in the first insulating sleeve 510, and is configured to receive ions transmitted from the first dynode 210, the first electron multiplier 310 is connected to a signal board, and is processed to obtain a detection value of positive ions; the second electron multiplier 320 is disposed in the second insulating sleeve 520, and is configured to receive ions transmitted from the second dynode 220, the second electron multiplier 320 is connected to a signal board, and is processed to obtain a detection value of negative ions.

[0031] The present invention does not limit the number of electron multipliers to two. In one embodiment, there is only one electron multiplier 300. Figure 5As shown, the angles of the impacted surfaces of the first dynode 210 and the second dynode 220 relative to the horizontal plane are adjusted so that the electrons leaving the two dynodes after the impact are gathered to the same electron multiplier 300, and the electron multiplier 300 is connected to the signal board to process and obtain the detection values ​​of positive ions and negative ions.

[0032] In a specific embodiment, the positional relationship between the quadrupole exit lens 100, the deflection lens, and the dynodes is determined as follows: the distance between the impacted area of ​​the first dynode 210 and the exit surface of the quadrupole exit lens 100 is in the range of 18 to 25 mm, preferably 20 mm; the distance between the impacted area of ​​the second dynode 220 and the exit surface of the quadrupole exit lens 100 is in the range of 18 to 25 mm, preferably 20 mm; the distance between the impacted area of ​​the first dynode 210 and the impacted area of ​​the second dynode 220 is in the range of 40 to 80 mm, preferably 60 mm. The gap width range between the first deflection lens 410 and the exit surface of the quadrupole exit lens 100 is 5 to 10 mm, preferably 8 mm; the gap width range between the second deflection lens 420 and the exit surface of the quadrupole exit lens 100 is 5 to 10 mm, preferably 8 mm; the distance range between the first deflection lens 410 and the second deflection lens 420 is 10 to 15 mm, preferably 12 mm.

[0033] The working principle of the ion detection system of this embodiment is as follows: the ions generated by the mass spectrometer are focused and output through the quadrupole output lens 100, and the output ions include positive ions and negative ions; the first deflection lens 410 applies a negative voltage, and the second deflection lens 420 applies a positive voltage, based on the principle that the positive voltage deflection lens attracts negative ions and repels positive ions, and the negative voltage deflection lens attracts positive ions and repels negative ions, the positive ions and negative ions are separated. The positive ions move along the first path deviating from the second deflection lens 420, pass through the first opening 512 and reach the first dynode 210; the negative ions move along the second path deviating from the first deflection lens 410, pass through the second opening 522 and reach the second dynode 220; the positive ions hit the first dynode 210, and the negative ions hit the second dynode 220, and then the electrons after the collision are transmitted from the dynode to the electron multiplier, and the electron multiplier 300 converts the ions into electrons and outputs electrical signals. The signal board collects and processes the electrical signals, and converts them into ion detection values ​​according to the processing results.

[0034] The ion detection system of this embodiment can detect positive ions and negative ions at the same time, thereby improving the efficiency of ion detection. The electric field is applied to the ions through the first deflection lens 410 and the second deflection lens 420, so that the positive ions and negative ions are separated and collide with the first dynode 210 and the second dynode 220 respectively, thereby improving the detection sensitivity.

[0035] The first comparison The difference from the above embodiment is that the first deflection lens 410 and the second deflection lens 420 are not provided in this comparative example. Figure 6 As shown, the high voltage applied to the dynode generates an electric field, which achieves the separation of positive and negative ions, but the ion deflection angle is too small to reach the effective area of ​​the dynode.

[0036] The second comparison The difference from the above embodiment is that in this comparative example, the distance between the first deflection lens 410 / the second deflection lens 420 and the quadrupole exit lens 100 is increased to about 20 mm. Figure 7 As shown, the ions are deflected and move toward the dynode, but because the first deflection lens 410 / the second deflection lens 420 is too far away from the exit lens 100 , the ions cannot reach the effective area of ​​the dynode.

[0037] The present invention also provides an ion detection method, see Figure 8 , the detection method comprises the following steps: The ions generated by the mass spectrometer are focused and output using the quadrupole exit lens; Using two deflection lenses to apply an electric field to the ions output by the quadrupole output lens to separate positive ions from negative ions; The separated positive ions hit the first dynode, and the separated negative ions hit the second dynode, and the generated electrons are transferred to the electron multiplier; The signal board is used to collect and process the electrical signal output by the electron multiplier, and the signal is converted into the detection value of the ion according to the processing result of the signal board.

[0038] Specifically, the electric field is applied in the following manner: a negative voltage -V is applied to the first deflection lens, and a positive voltage V is applied to the second deflection lens; a voltage amplitude range V∈[Vmin, Vmax] is determined, and the range satisfies that the area where the ions impact the dynode is within a preset area range; the voltage applied to the first deflection lens and the second deflection lens is dynamically changed within the voltage amplitude range. In a specific embodiment, taking Vmin as 1000V and Vmax as 1200V as an example, the voltage amplitude V starts from 1000V, increases by 10V every 0.1 seconds until it reaches 1200V, and then decreases by 10V every 0.1 seconds until it returns to 1000V, and repeats in this way. In this way, the position where the ions impact on the dynode can be dynamically changed within a preset area range, avoiding fatigue of the impact position of the dynode or reducing the response efficiency.

[0039] It should be noted that the ion detection method provided in this embodiment and the ion detection system provided in the above embodiment belong to the same inventive concept, that is, the ion detection method of this embodiment can be applied to the ion detection system, and the entire content of the ion detection system embodiment is incorporated into the present ion detection method embodiment by reference.

[0040] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0041] The above is only a specific implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. An ion detection system, characterized in that: The invention comprises a quadrupole output lens (100), a first deflection lens (410), a second deflection lens (420), a first dynode (210) and a second dynode (220), wherein the quadrupole output lens (100) is configured to focus and output ions generated by a mass spectrometer; The first dynode (210) is accommodated in a first insulating sleeve (510), and the first insulating sleeve (510) is provided with a first opening (512); the second dynode (220) is accommodated in a second insulating sleeve (520), and the second insulating sleeve (520) is provided with a second opening (522); The first deflection lens (410) and the second deflection lens (420) are symmetrically arranged on both sides of the exit port of the quadrupole exit lens (100), and the paths of ions output by the quadrupole exit lens (100) are changed by applying an electric field, so that positive ions pass through the first opening (512) along a first path deviating from the second deflection lens (420) and reach the first dynode (210), and negative ions pass through the second opening (522) along a second path deviating from the first deflection lens (410) and reach the second dynode (220).

2. The ion detection system according to claim 1, characterized in that: The first deflection lens (410) and the second deflection lens (420) are both strip-shaped, and their axes in the length direction are both parallel to the exit surface of the quadrupole exit lens (100).

3. The ion detection system according to claim 2, characterized in that: The width of the gap between the first deflection lens (410) and the exit surface of the quadrupole exit lens (100) ranges from 5 to 10 mm; The width of the gap between the second deflecting lens (420) and the exit surface of the quadrupole exit lens (100) ranges from 5 to 10 mm.

4. The ion detection system according to claim 2, characterized in that: The distance between the first deflecting lens (410) and the second deflecting lens (420) ranges from 10 to 15 mm.

5. The ion detection system according to claim 1, characterized in that: The first dynode (210) and the second dynode (220) are symmetrically arranged on both sides of the exit port of the quadrupole exit lens (100), and the impacted surfaces of the first dynode (210) and the second dynode (220) are perpendicular to the exit surface of the quadrupole exit lens (100).

6. The ion detection system according to claim 1, characterized in that: The distance between the impacted area of ​​the first dynode (210) and the exit surface of the quadrupole exit lens (100) ranges from 18 to 25 mm; The distance between the impacted area of ​​the second dynode (220) and the exit surface of the quadrupole exit lens (100) ranges from 18 to 25 mm.

7. The ion detection system according to claim 1, characterized in that: The distance between the struck area of ​​the first dynode (210) and the struck area of ​​the second dynode (220) ranges from 40 to 80 mm.

8. The ion detection system according to any one of claims 1 to 7, characterized in that: Also included is an electron multiplier (300) configured to receive ions transferred from the first dynode (210) and the second dynode (220).

9. The ion detection system according to any one of claims 1 to 7, characterized in that: It also includes a first electron multiplier (310) and a second electron multiplier (320), wherein the first electron multiplier (310) is disposed in the first insulating sleeve (510) and is configured to receive ions transferred from the first dynode (210); The second electron multiplier (320) is disposed in the second insulating sleeve (520) and is configured to receive ions transferred from the second dynode (220).

10. An ion detection method, characterized in that: The following steps are involved: The ions generated by the mass spectrometer are focused and output using the quadrupole exit lens; Using two deflection lenses to apply an electric field to the ions output by the quadrupole output lens to separate positive ions from negative ions; The separated positive ions hit the first dynode, and the separated negative ions hit the second dynode, and the generated electrons are transferred to the electron multiplier; The signal board is used to collect and process the electrical signal output by the electron multiplier, and the signal is converted into the detection value of the ion according to the processing result of the signal board.

11. The ion detection method according to claim 10, characterized in that: The electric field is applied by: Applying a negative voltage -V to the first deflection lens and applying a positive voltage V to the second deflection lens; Determine a voltage amplitude range V∈[Vmin,Vmax], which satisfies that the region where the ions impact the dynode is within a preset region; The voltage applied to the first deflecting lens and the second deflecting lens is dynamically changed within the voltage amplitude range.

12. An ion detection method, characterized in that: Based on the ion detection system according to any one of claims 1 to 9, the following steps are performed: The ions generated by the mass spectrometer are focused and output using the quadrupole exit lens; Using two deflection lenses to apply an electric field to the ions output by the quadrupole output lens to separate positive ions from negative ions; The separated positive ions hit the first dynode, and the separated negative ions hit the second dynode, and the generated electrons are transferred to the electron multiplier; The signal board is used to collect and process the electrical signal output by the electron multiplier, and the signal is converted into the detection value of the ion according to the processing result of the signal board.

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