阅读说明：本技术 一种离子过滤装置及方法 (Ion filtering device and method ) 是由 袁震 赵西官 于 2021-02-26 设计创作，主要内容包括：本发明涉及一种离子过滤装置及方法,其特征在于,包括外壳、脉冲高压电源和数字延时脉冲发生器,所述外壳内设置有飞行时间质谱加速装置、减速装置、探测器和静电聚焦透镜；位于待选质离子的初始飞行轴线上,所述外壳的顶部固定设置用于对待选质离子进行加速的所述飞行时间质谱加速装置；所述外壳的底部固定设置所述减速装置、探测器和静电聚焦透镜；所述飞行时间质谱加速装置和减速装置分别连接所述脉冲高压电源；所述脉冲高压电源还连接所述数字延时脉冲发生器,本发明可以广泛应用于质谱分析领域中。(The invention relates to an ion filtering device and a method, which are characterized by comprising a shell, a pulse high-voltage power supply and a digital delay pulse generator, wherein a flight time mass spectrum accelerating device, a decelerating device, a detector and an electrostatic focusing lens are arranged in the shell; the time-of-flight mass spectrum accelerating device is fixedly arranged at the top of the shell and is used for accelerating the ions of the to-be-selected substance; the speed reducer, the detector and the electrostatic focusing lens are fixedly arranged at the bottom of the shell; the flight time mass spectrum accelerating device and the decelerating device are respectively connected with the pulse high-voltage power supply; the pulse high-voltage power supply is also connected with the digital delay pulse generator, and the invention can be widely applied to the field of mass spectrometry.)

1. An ion filtering device is characterized by comprising a shell, a pulse high-voltage power supply and a digital delay pulse generator, wherein a flight time mass spectrum accelerating device, a decelerating device, a detector and an electrostatic focusing lens are arranged in the shell;

the time-of-flight mass spectrum accelerating device is fixedly arranged at the top of the shell and is used for accelerating the ions of the to-be-selected substance; the bottom of the shell is fixedly provided with the speed reduction device, the detector and the electrostatic focusing lens, the speed reduction device is used for reducing the speed of ions of a substance to be selected, the detector is used for acquiring the information of the ions of the substance to be selected, and the electrostatic focusing lens is used for focusing and collecting target ions with selected mass;

the flight time mass spectrum accelerating device and the decelerating device are respectively connected with the pulse high-voltage power supply, and the pulse high-voltage power supply is used for applying pulse high-voltage electricity to the flight time mass spectrum accelerating device and the decelerating device;

the digital delay pulse generator is used for adjusting the pulse width of the pulse high-voltage electricity applied by the pulse high-voltage power supply, so that the deceleration field of the deceleration device can counteract the kinetic energy of the selected mass target ions obtained in the time-of-flight mass spectrum acceleration device.

2. An ion filtering device is characterized by comprising a shell, a pulse high-voltage power supply and a digital delay pulse generator, wherein a flight time mass spectrum accelerating device, a decelerating device, an ion reflector, a detector and an electrostatic focusing lens are arranged in the shell;

the top of the shell is sequentially provided with the time-of-flight mass spectrum accelerating device, the decelerating device, the detector and the electrostatic focusing lens; the ion reflector is fixedly arranged at the bottom of the shell, the flight time mass spectrum accelerating device is used for accelerating ions of a substance to be selected, the ion reflector is used for reflecting the accelerated ions of the substance to be selected, the decelerating device is used for decelerating the reflected ions of the substance to be selected, the detector is used for acquiring information of the ions of the substance to be selected, and the electrostatic focusing lens is used for focusing and collecting target ions of the selected mass;

the flight time mass spectrum accelerating device and the decelerating device are respectively connected with the pulse high-voltage power supply, and the pulse high-voltage power supply is used for applying pulse high-voltage electricity to the flight time mass spectrum accelerating device and the decelerating device;

the digital delay pulse generator is used for adjusting the pulse width of the pulse high-voltage electricity applied by the pulse high-voltage electricity, so that the deceleration field of the deceleration device can counteract the kinetic energy obtained by the deceleration field flight time mass spectrum acceleration device of the target ions with the selected mass.

3. The ion filtering device according to claim 1 or 2, wherein the time-of-flight mass spectrometer accelerating device and the decelerating device respectively comprise at least three first grid electrode plates, the at least three first grid electrode plates are all arranged in the housing in parallel at intervals, and a rectangular through hole for passing ions to be selected to accelerate or decelerate the ions to be selected is formed in the center of each first grid electrode plate.

4. The ion filtering device according to claim 2, wherein the time-of-flight mass spectrometer acceleration device and the deceleration device are integrated, and comprise at least three second grid electrode plates, the at least three second grid electrode plates are arranged in the housing at intervals in parallel, and each second grid electrode plate is provided with two rectangular through holes in parallel, which are respectively used for accelerating and decelerating the ions to be selected by the ions to be selected.

5. An ion filter arrangement as claimed in claim 1 or 2, wherein the ion filter arrangement comprises at least two of said pulsed high voltage power supplies and one of said digital time delay pulse generators;

each pulse high-voltage power supply is correspondingly connected with one grid electrode plate of the time-of-flight mass spectrum accelerating device and the last grid electrode plate of the decelerating device respectively, and the last grid electrode plates of the time-of-flight mass spectrum accelerating device and the last grid electrode plates of the decelerating device are grounded; each pulse high-voltage power supply is respectively connected with the digital delay pulse generator.

6. An ion filter arrangement as claimed in claim 1 or 2, wherein the ion filter arrangement comprises at least four of said pulsed high voltage power supplies and one of said digital time delay pulse generators;

at least two pulse high-voltage power supplies are respectively and correspondingly connected with a grid electrode plate of the flight time mass spectrum accelerating device, at least two pulse high-voltage power supplies are respectively and correspondingly connected with a grid electrode plate of the decelerating device, and the last grid electrode plates of the flight time mass spectrum accelerating device and the decelerating device are grounded; each pulse high-voltage power supply is respectively connected with the digital delay pulse generator.

7. An ion filter arrangement as claimed in claim 2, wherein the ion mirror comprises 33 oxygen-free copper electrode plates and 3 third grid electrode plates;

the two third grid electrode plates are arranged in parallel at intervals; the 33 oxygen-free copper electrode plates are arranged between the two third grid electrode plates at intervals in parallel; and the other third grid electrode plate is arranged among 33 oxygen-free copper electrode plates, and the ion reflector is divided into two-stage uniform electric field areas by the three third grid electrode plates.

8. An ion filtering device according to claim 1 or 2, wherein said electrostatic focusing lens is spaced 10mm from the decelerating field of said decelerating device.

9. An ion filtration method according to any one of claims 1 or 2, comprising:

1) setting an ion filtering device, applying pulse high-voltage electricity to a flight time mass spectrum accelerating device and a decelerating device through a pulse high-voltage power supply, and adjusting the pulse width of the pulse high-voltage electricity applied by the pulse high-voltage power supply through a digital delay pulse generator;

2) introducing ions of a substance to be selected into a set ion filtering device, and accelerating the ions of the substance to be selected by a flight time mass spectrum accelerating device;

3) the accelerated ions of the selected substance pass through a speed reducer without pulse high voltage electricity and are directly or after being reflected by an ion reflector and then impact on a detector, and the detector obtains the information of the ions of the selected substance;

4) the pulse high-voltage electricity applied by the pulse high-voltage power supply is adjusted to be the pulse width under the quality selection mode through the digital time-delay pulse generator, and the pulse width of the applied high-voltage pulse electricity is gradually increased through the digital time-delay pulse generator;

5) introducing ions of a substance to be selected into a set ion filtering device, and accelerating the ions of the substance to be selected by a flight time mass spectrum accelerating device;

6) the accelerated ions of the selected mass directly or after being reflected by an ion reflector enter a pulse high-voltage applied speed reducer for speed reduction, so that the upward kinetic energy of the target ions of the selected mass is reduced to zero, and only the speed in the initial direction is remained;

7) and focusing and collecting target ions of the selected mass only with the residual initial directional speed through an electrostatic focusing lens to realize the mass selection of the target ions of the selected mass.

10. The ion filtering method according to claim 9, wherein in the conventional mass spectrometry mode in step 1), the duration of the pulse width adjusted by the digital delay pulse generator is from the acceleration of the candidate ions to the time when all the candidate ions fly out of the acceleration field;

in the mass selection mode, the duration of the pulse width adjusted by the digital delay pulse generator is completely offset by the deceleration field from the acceleration of the ions to be selected to the kinetic energy of the target ions with the selected mass; or when one group of at least two pulse high-voltage power supplies are connected with the flight time mass spectrum accelerating device and the other group of at least two pulse high-voltage power supplies are connected with the decelerating device, the digital delay pulse generator adjusts the pulse width of the pulse high-voltage power supply connected with the decelerating device, counteracts the initial accelerating speed, only keeps the initial axial speed, and realizes quality selection.

Technical Field

The invention relates to an ion filtering device and method, and belongs to the field of mass spectrometry.

Background

Ion filtering (mass filtering, mass selection or mass selection) is an important means in the field of mass spectrometry, which is to purposefully select ions of a specific charge-to-mass ratio (ions of other charge-to-mass ratios are filtered) from ion packets containing a series of different charge-to-mass ratios generated by an ion source by means of an electric field, a magnetic field or an electromagnetic field for targeted characterization, such as collision-induced dissociation, ion molecular reactions.

Quadrupole rods are the most commonly used ion filters and are widely used in mass spectrometry instruments such as multiple quadrupole rods, quadrupole rod-time of flight, and the like. However, quadrupole rods suffer from the following significant disadvantages: 1) the mass selection passing rate of the quadrupole (i.e. the number of ions with a specific charge-to-mass ratio after mass selection/the number of corresponding ions before mass selection x 100%) is related to the mass of the ions, and as the mass of the ions becomes larger, the mass selection passing rate is significantly reduced, for example, 1000amu ions, and the mass selection passing rate of the quadrupole is less than 1%, so that the quadrupole is limited to be mainly used for ion filtration or analysis within 2000 amu; 2) the machining and assembling precision of the quadrupole rods is extremely high, for example, the parallelism of the four electrode rods is required to be about 2 mu m, and only a few companies with a few refractive indexes can produce the quadrupole rods; 3) quadrupole rod selection requires a high voltage radio frequency power supply (the radio frequency voltage is proportional to the mass of ions), and impedance matching of a radio frequency circuit also has a certain barrier.

Disclosure of Invention

In view of the above problems, it is an object of the present invention to provide an ion filtering apparatus and method having a high mass selection throughput, low requirements for machining and assembly accuracy, and a throughput that is independent of ion mass.

In order to achieve the purpose, the invention adopts the following technical scheme: an ion filtering device comprises a shell, a pulse high-voltage power supply and a digital delay pulse generator, wherein a flight time mass spectrum accelerating device, a decelerating device, a detector and an electrostatic focusing lens are arranged in the shell;

the time-of-flight mass spectrum accelerating device is fixedly arranged at the top of the shell and is used for accelerating the ions of the to-be-selected substance; the bottom of the shell is fixedly provided with the speed reduction device, the detector and the electrostatic focusing lens, the speed reduction device is used for reducing the speed of ions of a substance to be selected, the detector is used for acquiring the information of the ions of the substance to be selected, and the electrostatic focusing lens is used for focusing and collecting target ions with selected mass;

the flight time mass spectrum accelerating device and the decelerating device are respectively connected with the pulse high-voltage power supply, and the pulse high-voltage power supply is used for applying pulse high-voltage electricity to the flight time mass spectrum accelerating device and the decelerating device;

the digital delay pulse generator is used for adjusting the pulse width of the pulse high-voltage electricity applied by the pulse high-voltage power supply, so that the deceleration field of the deceleration device can counteract the kinetic energy of the selected mass target ions obtained in the time-of-flight mass spectrum acceleration device.

An ion filtering device comprises a shell, a pulse high-voltage power supply and a digital delay pulse generator, wherein a flight time mass spectrum accelerating device, a decelerating device, an ion reflector, a detector and an electrostatic focusing lens are arranged in the shell;

the top of the shell is sequentially provided with the time-of-flight mass spectrum accelerating device, the decelerating device, the detector and the electrostatic focusing lens; the ion reflector is fixedly arranged at the bottom of the shell, the flight time mass spectrum accelerating device is used for accelerating ions of a substance to be selected, the ion reflector is used for reflecting the accelerated ions of the substance to be selected, the decelerating device is used for decelerating the reflected ions of the substance to be selected, the detector is used for acquiring information of the ions of the substance to be selected, and the electrostatic focusing lens is used for focusing and collecting target ions of the selected mass;

the flight time mass spectrum accelerating device and the decelerating device are respectively connected with the pulse high-voltage power supply, and the pulse high-voltage power supply is used for applying pulse high-voltage electricity to the flight time mass spectrum accelerating device and the decelerating device;

the digital delay pulse generator is used for adjusting the pulse width of the pulse high-voltage electricity applied by the pulse high-voltage electricity, so that the deceleration field of the deceleration device can counteract the kinetic energy obtained by the deceleration field flight time mass spectrum acceleration device of the target ions with the selected mass.

Furthermore, the time-of-flight mass spectrum accelerating device and the decelerating device respectively comprise at least three first grid electrode plates, the at least three first grid electrode plates are arranged in the shell in parallel at intervals, and a rectangular through hole for accelerating or decelerating the ions to be selected through the ions to be selected is formed in the center of each first grid electrode plate.

Furthermore, the time-of-flight mass spectrum accelerating device and the decelerating device are integrated and comprise at least three second grid electrode plates which are arranged in the shell in parallel at intervals, and each second grid electrode plate is provided with two rectangular through holes in parallel and used for accelerating and decelerating the ions of the to-be-selected substances respectively.

Furthermore, the ion filtering device comprises at least two pulse high-voltage power supplies and one digital time delay pulse generator;

each pulse high-voltage power supply is correspondingly connected with one grid electrode plate of the time-of-flight mass spectrum accelerating device and the last grid electrode plate of the decelerating device respectively, and the last grid electrode plates of the time-of-flight mass spectrum accelerating device and the last grid electrode plates of the decelerating device are grounded; each pulse high-voltage power supply is respectively connected with the digital delay pulse generator.

Furthermore, the ion filtering device comprises at least four pulse high-voltage power supplies and one digital time delay pulse generator;

at least two pulse high-voltage power supplies are respectively and correspondingly connected with a grid electrode plate of the flight time mass spectrum accelerating device, at least two pulse high-voltage power supplies are respectively and correspondingly connected with a grid electrode plate of the decelerating device, and the last grid electrode plates of the flight time mass spectrum accelerating device and the decelerating device are grounded; each pulse high-voltage power supply is respectively connected with the digital delay pulse generator.

Further, the ion reflector comprises 33 oxygen-free copper electrode plates and 3 third grid electrode plates;

the two third grid electrode plates are arranged in parallel at intervals; the 33 oxygen-free copper electrode plates are arranged between the two third grid electrode plates at intervals in parallel; and the other third grid electrode plate is arranged among 33 oxygen-free copper electrode plates, and the ion reflector is divided into two-stage uniform electric field areas by the three third grid electrode plates.

Further, the electrostatic focusing lens is 10mm away from the decelerating field of the decelerating device.

A method of ion filtration comprising:

1) setting an ion filtering device, applying pulse high-voltage electricity to a flight time mass spectrum accelerating device and a decelerating device through a pulse high-voltage power supply, and adjusting the pulse width of the pulse high-voltage electricity applied by the pulse high-voltage power supply through a digital delay pulse generator;

2) introducing ions of a substance to be selected into a set ion filtering device, and accelerating the ions of the substance to be selected by a flight time mass spectrum accelerating device;

3) the accelerated ions of the selected substance pass through a speed reducer without pulse high voltage electricity and are directly or after being reflected by an ion reflector and then impact on a detector, and the detector obtains the information of the ions of the selected substance;

4) the pulse high-voltage electricity applied by the pulse high-voltage power supply is adjusted to be the pulse width under the quality selection mode through the digital time-delay pulse generator, and the pulse width of the applied high-voltage pulse electricity is gradually increased through the digital time-delay pulse generator;

5) introducing ions of a substance to be selected into a set ion filtering device, and accelerating the ions of the substance to be selected by a flight time mass spectrum accelerating device;

6) the accelerated ions of the selected mass directly or after being reflected by an ion reflector enter a pulse high-voltage applied speed reducer for speed reduction, so that the upward kinetic energy of the target ions of the selected mass is reduced to zero, and only the speed in the initial direction is remained;

7) and focusing and collecting target ions of the selected mass only with the residual initial directional speed through an electrostatic focusing lens to realize the mass selection of the target ions of the selected mass.

Further, in the step 1), in a conventional mass spectrum mode, the duration of the pulse width adjusted by the digital delay pulse generator starts from the acceleration of the ions of the to-be-selected substance to the time when all the ions of the to-be-selected substance fly out of the acceleration field;

in the mass selection mode, the duration of the pulse width adjusted by the digital delay pulse generator is completely offset by the deceleration field from the acceleration of the ions to be selected to the kinetic energy of the target ions with the selected mass; or when one group of at least two pulse high-voltage power supplies are connected with the flight time mass spectrum accelerating device and the other group of at least two pulse high-voltage power supplies are connected with the decelerating device, the digital delay pulse generator adjusts the pulse width of the pulse high-voltage power supply connected with the decelerating device, counteracts the initial accelerating speed, only keeps the initial axial speed, and realizes quality selection.

Due to the adoption of the technical scheme, the invention has the following advantages:

1. the ion filtering device is based on the flight time mass spectrum, and is innovatively coupled with the speed reducer and the focusing device of ions at the tail end of the mass spectrum, so that the purpose of mass filtering can be realized, the advantage of large mass detection range of the flight time mass spectrum is fully inherited, and the ion filtering device is suitable for mass filtering of large-mass ions.

2. Under the condition of single mass resolution, the mass selection throughput rate of the invention is obviously superior to that of a quadrupole rod when the mass selection throughput rate is more than 300amu, the invention shows better throughput rate and quality-independent property, and the assembly precision requirement of the speed reducing device and the flight time mass spectrum of the invention is far lower than that of the quadrupole rod, thereby being beneficial to popularization.

3. According to specific needs, the flight time mass spectrum can adopt linearity, reflection and multiple reflection, and electrode plates of mass spectrum accelerating, reflecting and decelerating devices can all adopt various forms such as net and non-net, so that the mass filtering effects of different resolutions and permeability are realized, for example: the mass spectrum coupling speed reduction and focusing device using the multi-reflection non-grid electrode plate can realize the ultra-large quality (10)⁴～10⁵amu) high resolution, high transmission mass filtration; the mass spectrum coupling speed reduction and focusing device using the single-reflection meshed electrode plate can realize a mass filtering device with slightly low mass filtering performance and small volume, and has a very flexible structure.

4. The power supply system of the invention is very simple, the deceleration device can use an independent power supply or share part of the power supply with the mass spectrum, for example, when sharing with the pulse acceleration power supply of the mass spectrum, only the duration (pulse width) of the pulse needs to be adjusted, and the invention can be widely applied to the field of mass spectrum analysis.

Drawings

FIG. 1 is a schematic structural diagram of an apparatus provided in embodiment 1 of the present invention;

FIG. 2 is a schematic structural diagram of an apparatus provided in embodiment 2 of the present invention;

FIG. 3 is a schematic diagram of a background spectrum and a selection signal measured by the device of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. In the description of the present invention, it is to be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Time of flight (TOF) Mass Spectrometry is the mass detection Range in all Mass Spectrometry types (10)⁰～10⁹amu) and low machining and assembling precision (machining and assembling precision of parts such as acceleration, reflection, detection and the like is 10¹～10²Mum) while the power supply system is relatively simple requiring only several pulsed high voltages (for ion acceleration) and dc high voltages (for mirrors and detectors). The flight time mass spectrum can be divided into a linear type (no reflector), a reflective type (ReTOF) and a multi-reflection type flight time (MRTOF) according to the types of a reflector (the space and the energy focusing capacity of ions can be greatly improved, and the resolution ratio is improved by one to several orders of magnitude compared with the linear type flight time mass spectrum), and can be divided into a grid type (an electric field is uniform, the ion flight track is simple to calculate, the electric field is uniform, but the ion passing rate is lower due to the influence of the grid), a grid type (an electric field is non-uniform, the ion flight track is difficult to control, but the ion passing rate is higher due to the influence of the grid, and the ion passing rate is suitable for multi-reflection) flight time mass spectrum according to the existence of the. The following description takes a meshed and reflective time-of-flight mass spectrum as an example, and the basic principle is as follows:

ions generated by an ion source (e.g., laser sputtering source, MALDI, electrospray, glow discharge, etc.) have a certain initial velocity (e.g., laser sputtering ultrasonic expansion source ion initial velocity is 10)²～10³m/s) are sprayed in a cone or plume shape, ions under the initial condition are not beneficial to obtaining high resolution by a time-of-flight mass spectrum, so that an ion beam with small radial divergence is formed through two collimation cone-shaped holes, and the ion beam after the specification of the cone-shaped holes enters an acceleration region of the time-of-flight.

The acceleration region of the time-of-flight mass spectrum comprises a plurality of grid electrodes (comprising an electrode frame, wherein the electrode frame comprises a first winding part and a second winding part which are oppositely arranged, grid mesh holes are defined by the electrode frame, and the grid meshes are arranged in the grid mesh holes and are formed by a plurality of metal wires which are arranged in parallel, two ends of the plurality of metal wires are respectively fixed on the first winding part and the second winding part to form grid mesh electrodes), and after the acceleration region is electrified, the grid mesh electrodes form a double-field acceleration region (namely, two regions with different electric field strengths can realize ion space focusing); at pulsed high voltage (duration typically 10)¹Mus), ions obtain kinetic energy in the direction perpendicular to the initial velocity, the kinetic energy obtained by the ions with different charge-to-mass ratios and different spatial positions is basically the same (the ion beam passing through the tapered hole still has certain spatial distribution, for example, the ion beam is distributed in a cylinder with the diameter of 2mm and the length of 30mm, so the kinetic energy obtained by the ions with different positions is slightly different), but the ion obtaining velocities with different charge-to-mass ratios are obviously different due to different masses; after a period of free flight, the free flight enters the ion mirror.

The ion reflector comprises a plurality of grid electrodes (the grid electrodes divide regions with different electric field intensities) and grid-free electrodes (the electric field is more uniform), the electrode plates are connected in series through a precise resistor for voltage division, and direct-current voltage is introduced to the grid electrodes to realize independent adjustment of the electric field intensities of different regions; ions enter the mirror and then are decelerated to zero, and then accelerated until the initial kinetic energy is recovered, but the speed direction of the initial acceleration is reversed. After being reflected by an ion reflector, ion packets with the same charge-mass ratio are gradually gathered and gathered in space and time, ion packets with different charge-mass ratios are gradually dispersed, space and flight time focus points of ions with different charge-mass ratios can be adjusted to a receiving surface of a detector (namely the front surface of a first piece of a microchannel plate) by adjusting accelerating voltage and reflecting voltage, the detector detects the flight time of the ions with different charge-mass ratios, and the flight time and the ion mass are converted to obtain a complete mass spectrum. The ion filter device of the present invention is not intended to obtain a mass spectrum, and therefore a deceleration device is provided in front of the detector to substantially cancel out the kinetic energy of ions of a particular charge-to-mass ratio to zero.

Example 1

As shown in fig. 1, the present embodiment provides an ion filtering apparatus, which includes a housing, a pulse high voltage power supply, and a digital delay pulse generator, wherein the housing is provided with a time-of-flight mass spectrometer acceleration device 1, a deceleration device 2, a detector 3, and an electrostatic focusing lens 4.

The time-of-flight mass spectrum accelerating device 1 is fixedly arranged at the top of the shell and is used for accelerating the ions of the substances to be selected.

The bottom of the shell is fixedly provided with a speed reduction device 2, a detector 3 and an electrostatic focusing lens 4, and the speed reduction device 2 is used for reducing the speed of ions of a substance to be selected; the detector 3 is used for acquiring information such as mass distribution, flight time and space focusing of the to-be-selected ions; the electrostatic focusing lens 4 is used to focus and collect target ions of a selected mass, enabling the selection of target ions of a selected mass.

The flight time mass spectrum accelerating device 1 and the decelerating device 2 are respectively connected with a pulse high-voltage power supply, the pulse high-voltage power supply is also connected with a digital delay pulse generator, and the pulse high-voltage power supply is used for applying pulse high-voltage electricity to the flight time mass spectrum accelerating device 1 and the decelerating device 2 (if electrostatic voltage is applied, the effect is the same as that of the ion reflector 6, and ions can be totally reflected); the digital time delay pulse generator is used for adjusting the pulse width of the pulse high-voltage electricity applied by the pulse high-voltage power supply, so that the deceleration field of the deceleration device 2 can basically counteract the kinetic energy of the selected mass target ions obtained in the time-of-flight mass spectrum acceleration device 1.

In a preferred embodiment, the time-of-flight mass spectrometer acceleration device 1 and deceleration device 2 each comprise at least three first grid electrode plates 5. In this embodiment, five first grid electrode plates 5 shown in fig. 1 are taken as a specific example for explanation, the five first grid electrode plates 5 are all arranged in the housing in parallel at intervals, a rectangular through hole is formed in the center of each first grid electrode plate 5, and is respectively used for accelerating or decelerating ions of the to-be-selected ions, the aperture of each rectangular through hole is 46cm × 30cm, and the ion passage rate of the first grid electrode plate 5 is 95%.

Example 2

The principle of this embodiment is the same as that of embodiment 1, and the present embodiment includes a housing, a pulse high voltage power supply, and a digital delay pulse generator, where the housing is provided with a flight time mass spectrometer acceleration device 1, a deceleration device 2, a detector 3, and an electrostatic focusing lens 4, and the difference is that the present embodiment further includes an ion mirror 6, and the arrangement positions of the flight time mass spectrometer acceleration device 1 and the deceleration device 2. As shown in fig. 2, the present embodiment provides an ion filtering apparatus, which includes a housing, a pulse high voltage power supply, and a digital delay pulse generator, wherein the housing is provided with a flight time mass spectrum accelerating device 1, a decelerating device 2, a detector 3, an electrostatic focusing lens 4, and an ion mirror 6.

The top of the shell is sequentially provided with a time-of-flight mass spectrum accelerating device 1, a decelerating device 2, a detector 3 and an electrostatic focusing lens 4 on the initial flight axis of the ions to be selected; the bottom of the shell is fixedly provided with an ion reflector 6, and the flight time mass spectrum accelerating device 1 is used for accelerating ions to be selected; the ion reflector 6 is used for reflecting accelerated ions of the selected substances; the speed reduction device 2 is used for reducing the speed of the reflected ions of the substances to be selected; the detector 3 is used for acquiring information such as mass distribution, flight time and space focusing of the to-be-selected ions; the electrostatic focusing lens 4 is used for focusing and collecting target ions with selected mass, and realizes the mass selection of ions of the to-be-selected mass.

The flight time mass spectrum accelerating device 1 and the decelerating device 2 are respectively connected with a pulse high-voltage power supply, the pulse high-voltage power supply is also connected with a digital delay pulse generator, and the pulse high-voltage power supply is used for applying pulse high-voltage electricity to the flight time mass spectrum accelerating device 1 and the decelerating device 2; the digital time delay pulse generator is used for adjusting the pulse width of the pulse high-voltage electricity applied by the pulse high-voltage power supply, so that the deceleration field of the deceleration device 2 can basically counteract the kinetic energy of the target ions with the selected mass in the time-of-flight mass spectrum acceleration device 1.

In a preferred embodiment, the time-of-flight mass spectrometer acceleration device 1 and deceleration device 2 each comprise at least three first grid electrode plates 5. In the embodiment, five first grid electrode plates 5 are taken as a specific example for explanation, the five first grid electrode plates 5 are all arranged in the housing at intervals in parallel, a rectangular through hole is formed in the center of each first grid electrode plate 5 and is used for accelerating or decelerating ions to be selected respectively, the aperture of each rectangular through hole is 46cm × 30cm, and the ion passing rate of the first grid electrode plate 5 is 95%. In this way, the time-of-flight mass spectrometer acceleration device 1 and deceleration device 2 are electrically separated, and an acceleration field and a deceleration field can be applied at different times, and the strength and duration of the acceleration field and the deceleration field can also be different (different voltages and pulse widths can be used).

In a preferred embodiment, the time-of-flight mass spectrometer acceleration device 1 and the deceleration device 2 are integrated and comprise at least three second grid electrode plates 7. In this embodiment, five second grid electrode plates 7 shown in fig. 2 are taken as a specific example for explanation, the five second grid electrode plates 7 are arranged in the housing at intervals in parallel, each second grid electrode plate 7 is provided with two rectangular through holes in parallel, and the two rectangular through holes are respectively used for accelerating and decelerating ions of the to-be-selected ions, the aperture of each rectangular through hole is 46cm × 30cm, and the ion passage rate of the second grid electrode plate 7 is 95%. The time-of-flight mass spectrometer acceleration device 1 and deceleration device 2 are electrically connected (because the electrode plates are made of metal), that is, when a pulse high voltage is applied, an acceleration electric field and an acceleration electric field exist at the same time, and the strength and duration of the fields are the same (the voltage is the same).

In a preferred embodiment, the ion mirror 6 comprises 33 oxygen-free copper electrode plates 61 and 3 third grid electrode plates 62, which are divided by a 200K high precision resistor (ten thousandth precision). The two third grid electrode plates 62 are arranged in parallel at intervals and are positioned between the two third grid electrode plates 62, and the 33 oxygen-free copper electrode plates 61 are arranged in parallel at intervals. The other third grid electrode plate 62 is arranged between the 33 oxygen-free copper electrode plates 61, and the three third grid electrode plates 62 divide the ion reflector 6 into two-stage uniform electric field areas so as to conveniently adjust the second-order spatial focusing point of ions to be selected.

In the above embodiments, the ion filtering device uses a group of pulse high voltage power supplies, that is, includes at least two pulse high voltage power supplies and a digital delay pulse generator, and the number of the pulse high voltage power supplies is related to the number of grid electrode plates of the acceleration device 1 and the deceleration device 2 of the time-of-flight mass spectrometry. Each pulse high-voltage power supply is correspondingly connected with a first grid electrode plate 5 or a second grid electrode plate 7 of the time-of-flight mass spectrum accelerating device 1 and the decelerating device 2 respectively, and the last first grid electrode plate 5 or the second grid electrode plate 7 of the time-of-flight mass spectrum accelerating device 1 and the decelerating device 2 are grounded. Each pulse high-voltage power supply is respectively connected with the digital delay pulse generator, and each pulse high-voltage power supply receives the trigger of one path of pulse on the digital delay pulse generator and works simultaneously.

In the above embodiments, the ion filtering apparatus includes at least four pulsed high voltage power supplies and one digital delay pulse generator, and the number of the pulsed high voltage power supplies is related to the number of grid electrode plates of the time-of-flight mass spectrometry accelerating device 1 and the decelerating device 2. At least two pulse high-voltage power supplies are respectively and correspondingly connected with a first grid electrode plate 5 or a second grid electrode plate 7 of the flight time mass spectrum accelerating device 1, at least two pulse high-voltage power supplies are respectively and correspondingly connected with a first grid electrode plate 5 or a second grid electrode plate 7 of the decelerating device 2, and the last first grid electrode plate 5 or the second grid electrode plate 7 of the flight time mass spectrum accelerating device 1 and the decelerating device 2 are grounded. Each pulse high-voltage power supply is respectively connected with the digital delay pulse generator, and each pulse high-voltage power supply receives the trigger of one path of pulse on the digital delay pulse generator and works simultaneously.

In the above embodiments, the detector 3 may be a compact detector.

In the above embodiments, the electrostatic focusing lens 4 is 10mm away from the decelerating field of the decelerating device 2.

Example 3

The embodiment provides an ion filtering method, which comprises the following steps:

1) the ion filtering device in embodiment 1 or embodiment 2 of the present invention is configured to apply a pulse high voltage power to the time-of-flight mass spectrometer acceleration device 1 and the deceleration device 2 by a pulse high voltage power supply, and adjust the pulse width of the pulse high voltage power applied by the pulse high voltage power supply by a digital delay pulse generator.

In a conventional mass spectrum mode, the duration of the pulse width regulated by the digital delay pulse generator starts from the acceleration of the ions of the substance to be selected to the time when all the ions of the substance to be selected fly out of the acceleration field.

In the mass selection mode, the duration of the pulse width adjusted by the digital delay pulse generator is completely offset by the deceleration field from the acceleration of the ions of the to-be-selected mass to the kinetic energy of the target ions of the selected mass, wherein for the time-of-flight mass spectrum accelerating device 1 and the decelerating device 2 for electric separation, the acceleration can be carried out according to the conventional mass spectrum mode, the duration of the acceleration field is until all the ions of the to-be-selected mass fly out of the acceleration field, and the deceleration field is completely offset by the deceleration field from the ions entering the deceleration field to the kinetic energy of the target ions of the selected mass. When the flight time mass spectrum accelerating device 1 and the decelerating device 2 are respectively connected with different pulse high-voltage power supplies, namely two groups of pulse high-voltage power supplies are adopted, one group of pulse high-voltage power supplies are used for accelerating, and the other group of pulse high-voltage power supplies are used for decelerating, so that the decelerated pulse high-voltage power supplies are unrelated to the accelerated pulse high-voltage power supplies, finally, the pulse width of the pulse high-voltage power supply connected with the decelerating device 2 can be adjusted by a digital delay pulse generator to offset the initial accelerating speed, only the initial axial speed is reserved, and quality selection is realized.

2) And (3) introducing ions of the to-be-selected substance into a set ion filtering device, accelerating the ions of the to-be-selected substance by the time-of-flight mass spectrum accelerating device 1, and performing the step 3) or 4).

3) The ion reflector 6 reflects the accelerated ions of the selected substance.

4) The accelerated ions of the selected substance pass through the decelerating device 2 without pulse high voltage and impact on the detector 3, and the detector 3 acquires information of mass distribution (namely a background map), flight time, space focusing and the like of the ions of the selected substance.

5) The pulse high-voltage electricity applied by the pulse high-voltage power supply is adjusted to be the pulse width under the quality selection mode through the digital time delay pulse generator, and the pulse width of the applied high-voltage pulse electricity is gradually increased through the digital time delay pulse generator, and the method specifically comprises the following steps:

and 5.1) regulating the pulse high-voltage electricity applied by the pulse high-voltage power supply to be the pulse width under the selection mode through a digital delay pulse generator.

And 5.2) setting a pulse width searching starting point of the high-voltage pulse electricity as the flight time of the selected mass target ions in the ions to be selected, and gradually increasing the pulse width of the applied high-voltage pulse electricity by using a digital delay pulse generator by taking 10ns as a stepping unit.

6) And (3) introducing ions of the to-be-selected substance into a set ion filtering device, accelerating the ions of the to-be-selected substance by the time-of-flight mass spectrum accelerating device 1, and performing the step 7) or 8).

7) The ion reflector 6 reflects the accelerated ions of the selected substance.

8) The accelerated ions of the to-be-selected mass are decelerated through the deceleration device 2, so that the upward kinetic energy of the target ions of the selected mass is reduced to zero, and only the velocity in the initial direction is remained, specifically:

ions with small mass and large speed in the ions to be selected enter a pulse deceleration field of the deceleration device 2, the pulse width of the pulse deceleration field is continued until the ions with small mass and large speed can be completely decelerated, and the ions begin to accelerate reversely and fly downwards after being synthesized with an initial speed vector;

on the contrary, the ions with large mass and small speed in the ions to be selected enter the pulse deceleration field of the deceleration device 2, at this time, the ions with large mass cannot be completely decelerated by the pulse width duration of the pulse deceleration field, and part of kinetic energy flying upwards is still synthesized with the initial speed vector and flies upwards;

by properly adjusting the pulse width of the high-voltage pulse electricity, the upward kinetic energy of ions with moderate mass in the ions to be selected can be reduced to zero while the pulse deceleration field of the deceleration device 2 is removed, and only the speed in the initial direction remains, so that the ions can smoothly pass through the electrostatic focusing lens 4 at the rear part, and the mass selection of the ions with different charge-mass ratios is realized.

9) And focusing and collecting target ions of the selected mass only with the residual initial directional speed through the electrostatic focusing lens 4 to realize the mass selection of the target ions of the selected mass.

The signal peak area of the ion after mass selection is divided by the signal peak area of the corresponding mass ion in the background map, and the mass selection transmittance is calculated, and the specific test result is shown in fig. 3, wherein each peak in the coordinate axis below the fig. 3 is a signal selected independently, and the result shows that the ion filtering device is feasible, the mass selection transmittance of the ion with larger mass is greater than 3% (superior to the mass selection transmittance of a quadrupole under the same condition), and the ion filtering device shows good property that the transmittance is independent of the mass.

The above embodiments are only used for illustrating the present invention, and the structure, connection mode, manufacturing process, etc. of the components may be changed, and all equivalent changes and modifications performed on the basis of the technical solution of the present invention should not be excluded from the protection scope of the present invention.