Tri-state ion gate and Hadamard transform ion mobility spectrometer

Abstract

The invention belongs to the technical field of component detection, and relates to a three-state ion gate and a Hadamard transform ion mobility spectrometer. The three-state ion gate is arranged in the Hadamard transform ion mobility spectrometer and comprises a first grid mesh, a second grid mesh and a third grid mesh which are sequentially and separately arranged in the direction from a reaction region to a drift region; the grid voltage regulation and control module is used for controlling the voltage of the second grid to be larger than the voltage of the third grid and smaller than the voltage of the first grid within a first preset time when the modulation signal output by the spectral modulation Hadamard transform gating unit is a first level signal; when the modulation signal is converted from the first level signal to the second level signal, controlling the voltage of the second grid mesh to be greater than the voltage of the first grid mesh and the voltage of the third grid mesh within a second preset time; and when the modulation signal is a continuous second level signal, controlling the voltage of the second grid mesh to be smaller than the voltage of the first grid mesh and the third grid mesh. According to the scheme, the resolution and the signal-to-noise ratio of the ion mobility spectrometry obtained by the Hadamard transform example mobility spectrometer can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of component detection, and in particular to a three-state ion gate and a Hadamard transform ion mobility spectrometer. Background Art

[0002] A Hadamard transform ion mobility spectrometer is an instrument for analyzing ion characteristics, including an ionization source, a reaction region, an ion gate, a spectral modulation Hadamard transform gating unit, a drift region, an ion signal detection unit, and a spectral modulation Hadamard transform signal processing unit; wherein, the ion gate includes a grid and a grid voltage regulation module. During use, the ionization source converts neutral sample molecules into reaction ions, and these reaction ions enter the reaction region under the action of an electric field and react with the detected substance to obtain product ions. The spectral modulation Hadamard transform gating unit generates a pulse sequence to the grid voltage control module, and the grid voltage regulation module changes the grid voltage to control the opening and closing of the ion gate, so that the product ions pass through the ion gate in the form of pulses and enter the drift region. Under the action of the electric field in the drift region, product ions with different mobilities migrate to the ion signal detection unit at different speeds. The ion signal detection unit detects the product ions arriving at different times and outputs an ion mobility superposition spectrum. Finally, the spectral modulation Hadamard transform signal processing unit processes the ion mobility superposition spectrum to obtain an ion mobility spectrum. A peak in the ion mobility spectrum represents an ion with a certain mobility. Therefore, based on this ion mobility spectrum, rapid separation and identification of different ion components in a complex sample can be achieved.

[0003] The ion gate in the existing Hadamard transform ion mobility spectrometer is usually a Tyndall-Powell (TP) ion gate. The TP ion gate is composed of a grid G1 close to the reaction region and a grid G2 close to the drift region. When the pulse sequence output by the spectral modulation Hadamard transform gating unit is at a high level, the grid voltage regulation module makes the voltage VG1 of G1 greater than the voltage VG2 of G2, so that the electric field force generated between G1 and G2 pushes the product ions to move from the reaction region to the drift region, thereby realizing the opening of the TP ion gate and allowing the product ions to pass through; when the pulse sequence output by the spectral modulation Hadamard transform gating unit is at a low level, the grid voltage regulation module makes the voltage VG1 of G1 less than the voltage VG2 of G2, so that the electric field force generated between G1 and G2 prevents the product ions from moving from the reaction region to the drift region, thereby realizing the closing of the TP ion gate.

[0004] Since ions with a large mobility move fast under the action of an electric field, while ions with a small mobility move slowly. When the opening time of the TP ion gate is short, although product ions with a large mobility have more opportunities to quickly enter the drift region, due to the opening time limit, the number of ions entering the migration region is small, resulting in a small peak intensity corresponding to them in the migration spectrum, which is easily submerged in background noise or other strong peaks, thus affecting the detection result of the sample composition; when the opening time of the TP ion gate is long, the number of product ions with a small mobility entering the migration region increases, but since the moving speed of this part of the product ions in the migration region is slow, and the time to reach the ion signal detection unit is similar, the peaks generated by product ions with slightly different mobilities may merge, resulting in a low resolution for small-mobility ions and affecting the detection result. In addition, when the TP ion gate switches between the on and off states, the sudden change in the internal electric field direction will cause the aggregation of product ions and the enhancement of the Coulomb force between ions, thereby generating ion clusters. Since the ion cluster signal is different from the normal single-ion signal, additional peaks, i.e., false peaks, will appear in the ion mobility spectrum, further affecting the accuracy of the sample composition detection result.

[0005] In summary, the ion gate in the existing Hadamard transform ion mobility spectrometer cuts the product ions unsatisfactorily, resulting in a low resolution of the generated ion mobility spectrum and the existence of false peaks, affecting the accuracy of the sample composition detection result. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the problem that the ion gate in the existing Hadamard transform ion mobility spectrometer cuts the product ions unsatisfactorily, resulting in a low resolution of the generated ion mobility spectrum and the existence of false peaks, affecting the accuracy of the sample composition detection result.

[0007] To solve the above technical problem, the present invention provides a three-state ion gate, which is arranged in a Hadamard transform ion mobility spectrometer and includes: A first grid, a second grid, and a third grid that are sequentially and separately arranged along the direction from the reaction region to the drift region; A grid voltage regulation module, which is connected to the spectral modulation Hadamard transform gating unit, the first grid, the second grid, and the third grid, and is used to regulate the voltages of the first grid, the second grid, and the third grid based on the modulation signal output by the spectral modulation Hadamard transform gating unit, so as to control the on and off states of the three-state ion gate; Wherein, when the modulation signal is a first level signal, the voltage of the second grid is greater than the voltage of the third grid and less than the voltage of the first grid within a first preset time; When the modulation signal is converted from the first level signal to a second level signal, the voltage of the second grid is greater than the voltages of the first grid and the third grid within a second preset time; When the modulation signal is a continuous second-level signal, the voltage of the second grid is less than the voltages of the first grid and the third grid within a third preset time.

[0008] Preferably, when the first-level signal is a high-level signal, the second-level signal is a low-level signal; when the first-level signal is a low-level signal, the second-level signal is a high-level signal.

[0009] Preferably, the voltages of the first grid and the third grid are constant values, and the voltage of the first grid is greater than the voltage of the third grid.

[0010] Preferably, when the modulation signal is a first-level signal, the voltage value of the second grid is one-half of the sum of the voltage values of the first grid and the third grid.

[0011] Preferably, the value range of the first preset time is [2 μs, 600 μs]; and / or the value range of the second preset time is [1 μs, 300 μs].

[0012] Preferably, the distances between the first grid and the second grid, and between the second grid and the third grid have a value range of [0.5 mm, 5 mm].

[0013] Preferably, when the sample to be detected is dimethyl methylphosphonate, the voltage of the first grid is 2100 V, and the voltage of the third grid is 2000 V; when the modulation signal is a first-level signal, the voltage of the second grid is 2050 V; when the modulation signal is converted from a first-level signal to a second-level signal, the voltage of the second grid is 2150 V; when the modulation signal is a continuous second-level signal, the voltage of the second grid is 1950 V.

[0014] Preferably, the first preset time is 150 μs; the second preset time is 75 μs.

[0015] Preferably, the distances between the first grid and the second grid, and between the second grid and the third grid are 0.5 mm.

[0016] The present invention also provides a Hadamard transform ion mobility spectrometer, including the above-mentioned three-state ion gate.

[0017] The three-state ion gate provided by the present application has the following beneficial effects: When the modulation signal is the first-level signal, the grid voltage regulation module makes the voltage of the second grid greater than that of the third grid and less than that of the first grid within the first preset time, forming a forward electric field between the first grid, the second grid, and the third grid, and controlling the three-state ion gate to be in the open state within the first preset time, so that the product ions can migrate through the three-state ion gate to the drift region; when the modulation signal is converted from the first-level signal to the second-level signal, the grid voltage regulation module makes the second grid greater than the voltages of the first grid and the third grid within the second preset time. Although the three-state ion gate is in the closed state at this time, due to the large forward electric field between the second grid and the third grid, the high-mobility product ions remaining between the second grid and the third grid can still enter the drift region, solving the problem of low resolution of high-mobility product ions caused by a short gate opening time. At the same time, due to the reverse electric field between the first grid and the second grid, the low-mobility product ions remaining between the first grid and the second grid move towards the reaction region, thus avoiding the problem of low resolution caused by a large number of low-mobility product ions concentrating and moving towards the drift region when the gate opening time is long; when the modulation signal is a continuous second-level signal, the grid voltage regulation module makes the voltage of the second grid less than the voltages of the first grid and the third grid, forming a forward electric field between the first grid and the second grid and a reverse electric field between the second grid and the third grid, so that the product ions in the reaction region and between the second grid and the third grid all move towards the second grid, thereby replenishing the product ions to the three-state ion gate again. The three-state ion gate provided in this application divides the electric field inside the ion gate into two parts by using three grids, and controls the direction of the electric field in each part by changing the grid voltage, so as to control the bidirectional movement of the product ions between the three grids, shorten the width of the ion packet entering the drift region, and enable product ions with different mobilities to have higher resolution; at the same time, it avoids the problem of false peaks caused by the sudden change of the overall electric field direction inside the ion gate, resulting in the aggregation of product ions and the enhancement of the Coulomb force between ions to generate ion clusters, making the generated ion mobility spectrum more accurate, and thus improving the reliability of the sample component detection results. Description of the Drawings

[0018] In order to make the content of the present invention easier to be clearly understood, the following further describes the present invention in detail according to the specific embodiments of the present invention in combination with the drawings, where: Figure 1 is a schematic structural diagram of a three-state ion gate for a Hadamard transform ion mobility spectrometer provided by this application; Figure 2 is a schematic diagram of the voltage waveform of the three-state ion gate provided by this application; Figure 3 is a schematic diagram of the waveform of the three-state ion gate corresponding to the modulation signal provided by this application; where, Figure 3Among them, (a) is a schematic diagram of the three-state ion gate waveform corresponding to the modulation signal in the positive mode, Figure 3 and (b) is a schematic diagram of the three-state ion gate waveform corresponding to the modulation signal in the negative mode; Figure 4 This is a schematic diagram comparing the Hadamard transform ion mobility spectrometer provided by this application with the ion mobility spectrum obtained by the prior art. Specific embodiments

[0019] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the specific embodiments cited do not limit the present invention.

[0020] This application provides a three-state ion gate, which is arranged in a Hadamard transform ion mobility spectrometer, as Figure 1 shown. Specifically, the three-state ion gate includes: A first grid G1, a second grid G2, and a third grid G3 that are sequentially and discretely arranged along the direction from the reaction region to the drift region.

[0021] A grid voltage regulation module connected to the spectral modulation Hadamard transform gating unit, the first grid G1, the second grid G2, and the third grid G3.

[0022] Among them, the grid voltage regulation module is used to control the voltage VG2 of the second grid G2 to be greater than the voltage VG3 of the third grid G3 and less than the voltage VG1 of the first grid G1 within a first preset time when the modulation signal output by the spectral modulation Hadamard transform gating unit is a first level signal. When the modulation signal is converted from the first level signal to a second level signal, control the voltage VG2 of the second grid G2 to be greater than the voltage VG1 of the first grid G1 and the voltage VG3 of the third grid G3 within a second preset time. When the modulation signal is a continuous second level signal, control the voltage VG2 of the second grid G2 to be less than the voltage VG1 of the first grid G1 and the voltage VG3 of the third grid G3.

[0023] Specifically, in a Hadamard transform ion mobility spectrometer, the spectral modulation Hadamard transform gating unit generates an m-sequence (i.e., modulation signal) through a linear feedback shift register, constructs an S-circulant matrix from the m-sequence, and uses the m-sequence to control the opening and closing of the ion gate. Its control mode is divided into two types: if "1" in the sequence represents the opening of the ion gate, then "0" in the sequence represents the closing of the ion gate; if "0" in the sequence represents the opening of the ion gate, then "1" in the sequence represents the closing of the ion gate. The grid voltage regulation module regulates the grid voltage based on the preset control mode and the signal values in the modulation signal to control the ion gate switch, so that the product ions move from the reaction zone to the migration zone and reach the Faraday disk. Therefore, the signal detected by the Faraday disk is the superimposed signal modulated by the modulation signal, and the original ion mobility spectrum can be obtained by performing an inverse transform on this superimposed signal. Its principle is shown in the following formula: , , where, represents the circulant matrix constructed based on the m-sequence; represents the original ion mobility spectrum; represents the superimposed signal; is the inverse matrix of.

[0024] Based on the above Hadamard transform principle, the modulation signal generated by the spectral modulation Hadamard transform gating unit is in the form of a binary sequence. Therefore, when the first level signal in this application is a high-level signal (i.e., "1" in the binary sequence), the second level signal in this application is a low-level signal (i.e., "0" in the binary sequence). When the first level signal in this application is a low-level signal (i.e., "0" in the binary sequence), the second level signal in this application is a high-level signal (i.e., "1" in the binary sequence).

[0025] Furthermore, when the second level signal is a high-level signal 1, the modulation signal is a continuous second level signal indicating that the binary sequence contains consecutive 1s; when the second level signal is a low-level signal 0, the modulation signal is a continuous second level signal indicating that the binary sequence contains consecutive 0s.

[0026] Furthermore, in some embodiments, the voltages of the first grid G1 and the third grid G3 can be made constant values, and the voltage of the first grid G1 is greater than the voltage of the third grid G3. At this time, only by adjusting the voltage VG2 of the second grid G2 can the on-off state of the ion gate be controlled.

[0027] Further, when the voltage value VG2 of the second grid G2 is greater than the voltage of the third grid G3 and less than the voltage of the first grid G1, the voltage value VG2 can take one-half of the sum of the voltage values of the first grid G1 and the third grid G3, that is, VG2 = (VG1 + VG3) / 2.

[0028] Specifically, as Figure 2 shown in the voltage waveform schematic diagram of the three-state ion gate provided by the present application, when the modulation signal is the first level signal, the voltage VG2 of the second grid G2 is equal to V2, greater than the voltage VG3 of the third grid G3, and less than the voltage VG1 of the first grid G1. The voltages of the first grid G1, the second grid G2, and the third grid G3 gradually decrease. Therefore, a forward electric field exists between the first grid G1 and the second grid G2, and between the second grid G2 and the third grid G3. At this time, the three-state ion gate is in the open state, and the product ions in the reaction region can migrate to the drift region through the first grid G1, the second grid G2, and the third grid G3.

[0029] Since the product ions with a larger mobility move faster, while the product ions with a smaller mobility move slower, when the three-state ion gate is closed, there are small-mobility product ions that have not passed through the three-state ion gate between the first grid G1 and the second grid G2, and there are large-mobility product ions that have not passed through the three-state ion gate between the second grid G2 and the third grid G3.

[0030] When the modulation signal is converted from the first level signal to the second level signal, the present application does not directly adjust the electric field inside the ion gate to a reverse electric field, but makes the voltage VG2 of the second grid G2 equal to V3, greater than the voltage VG1 of the first grid G1 and the voltage VG3 of the third grid G3. At this time, a reverse electric field exists between the first grid G1 and the second grid G2, and a forward electric field exists between the second grid G2 and the third grid G3. The three-state ion gate is in the closed state, but the small-mobility product ions located between the first grid G1 and the second grid G2 can return to the reaction region under the action of the reverse electric field, avoiding the peak fusion caused by a large number of small-mobility product ions entering the drift region simultaneously, thereby affecting the resolution of small-mobility ions; the large-mobility product ions located between the second grid G2 and the third grid G3 can continue to migrate to the drift region under the action of the forward electric field, avoiding the problem of weak peak intensity caused by too few large-mobility product ions entering the drift region and improving the resolution of large-mobility ions.

[0031] When the modulation signal is a continuous second-level signal, the voltage VG2 of the second grid G2 is reduced to V1 until it is less than the voltages of the first grid G1 and the third grid G3. At this time, a forward electric field exists between the first grid G1 and the second grid G2, and the product ions in the reaction region move towards the second grid G2, so that the product ions can be replenished between the grids again to enter the drift region when the three-state ion gate is opened again.

[0032] It can be seen that when receiving the modulation signal for closing the three-state ion gate, the present application does not directly make the voltage VG2 of the second grid G2 less than the voltages of the first grid G1 and the third grid G3. Instead, it first continues to rise to V3 and remains for a period of time to compress the ion packet, and then drops to V1. By using this buffer state, the moving directions of product ions with different mobilities are changed, avoiding the problem that the number of product ions with large mobility entering the drift region is small due to the short opening time, and also solving the problem that a large number of product ions with small mobility enter the drift region due to the long opening time, thereby improving the resolution of product ions with different mobilities. At the same time, since in this state, product ions with different mobilities do not aggregate excessively, the generation of ion clusters is avoided, and thus the appearance of false peaks in the ion mobility spectrum affecting the detection results is avoided.

[0033] Furthermore, since the switching times of the ion gate will affect the resolution of the generated ion mobility spectrum, in some embodiments of the present application, the opening time of the three-state ion gate, that is, the value range of the first preset time is [2 μs, 600 μs]. For example, the first preset time can be 2 μs, 48 μs, 100 μs, 148 μs, 200 μs, 248 μs, 300 μs, 348 μs, 400 μs, 448 μs, 500 μs, 548 μs, 600 μs.

[0034] Furthermore, in order to make the product ions located between the grids migrate towards the reaction region or the drift region as soon as possible when the three-state ion gate is just closed and avoid ion aggregation, in some embodiments of the present application, the value range of the second preset time is [1 μs, 300 μs]. For example, the second preset time can be 1 μs, 50 μs, 100 μs, 150 μs, 200 μs, 250 μs, 300 μs.

[0035] Furthermore, if the distance between the grid meshes is too small, the electric field between the grid meshes is more likely to be affected by the edge effect, increasing the non-uniformity of the electric field and causing the movement trajectories of the product ions to be chaotic. If the distance is too large, the diffusion phenomenon of the product ions during migration is more obvious, resulting in the broadening of the ion packet during movement, thereby affecting the resolution of the ion mobility spectrometry. Therefore, in some embodiments of the present application, the distance between the first grid G1 and the second grid G2 and the distance between the second grid G2 and the third grid G3 are limited to [0.5 mm, 5 mm]. For example, the distance between each pair of grid meshes can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, or 5 mm. This can not only balance the uniformity of the electric field between the grid meshes but also balance the diffusion effect of the electric field on the product ions, improving the resolution of the ion mobility spectrometry and thus enhancing the accuracy of the sample detection results.

[0036] The ion mobility spectrometry distinguishes different working modes according to the positive or negative charge carried by the ions during migration. The three-state ion gate provided in the present application is applicable in both positive and negative modes, as Figure 3 shown in the schematic diagram of the waveform of the three-state ion gate corresponding to the modulation signal provided in the present application; where Figure 3 (a) in it is the schematic diagram of the waveform of the three-state ion gate corresponding to the modulation signal in the positive mode, Figure 3 (b) in it is the schematic diagram of the waveform of the three-state ion gate corresponding to the modulation signal in the negative mode.

[0037] It can be seen from the figure that when the working mode is the positive mode, since the product ions are positive ions and their movement direction is the same as the electric field direction, when the modulation signal is converted from the first level signal to the second level signal, the grid voltage control module controls the voltage VG2 of the second grid G2 to be greater than the voltages of the first grid G1 and the third grid G3 within the second preset time. When the modulation signal is a continuous second level signal, the grid voltage control module controls the voltage VG2 of the second grid G2 to be less than the voltages of the first grid G1 and the third grid G3. When the working mode is the negative mode, since the product ions are negative ions and their movement direction is opposite to the electric field direction, when the modulation signal is converted from the first level signal to the second level signal, the grid voltage control module controls the voltage VG2 of the second grid G2 to be less than the voltages of the first grid G1 and the third grid G3 within the second preset time. When the modulation signal is a continuous second level signal, the grid voltage control module controls the voltage VG2 of the second grid G2 to be greater than the voltages of the first grid G1 and the third grid G3.

[0038] Furthermore, since the compositions of different samples to be detected are different and their ion distributions are also different, the voltage values of the grid meshes and the switching times of the three-state ion gate are also different when detecting different samples to be detected.

[0039] In an example of the present application, when the sample to be detected is dimethyl methylphosphonate, the voltage VG1 of the first grid G1 is 2100 V, and the voltage VG3 of the third grid G3 is 2000 V; When the modulation signal is the first level signal, the voltage VG2 of the second grid G2 is 2050 V; When the modulation signal is converted from the first level signal to the second level signal, the voltage VG2 of the second grid G2 is 2150 V; When the modulation signal is a continuous second level signal, the voltage VG2 of the second grid G2 is 1950 V.

[0040] Further, when the sample to be detected is dimethyl methylphosphonate, the first preset time is 150 μs, and the second preset time is 75 μs.

[0041] Further, when the sample to be detected is dimethyl methylphosphonate, the distance between the first grid G1 and the second grid G2 and the distance between the second grid G2 and the third grid G3 are 0.5 mm.

[0042] Based on the three-state ion gate provided in the above embodiments, the embodiment of the present application further provides a Hadamard transform ion mobility spectrometer, and the Hadamard transform ion mobility spectrometer includes the above three-state ion gate.

[0043] This embodiment also uses the Hadamard transform ion mobility spectrometer provided in the above embodiment and the prior art to detect dimethyl methylphosphonate respectively. When detecting, the order of the Hadamard matrix is 511, and the opening time of the ion gate is 150 μs. As Figure 4 Shown is a comparison schematic diagram of ion mobility spectra obtained when using the Hadamard transform ion mobility spectrometer provided in the present application and the prior art to detect dimethyl methylphosphonate; among them, the ion mobility spectra obtained by the prior art include the ion mobility spectra obtained by using the signal averaging method and the ion mobility spectra obtained by using the Hadamard transform ion mobility spectrometer with a TP ion gate. In the figure, "*" represents the false peaks in the ion mobility spectra.

[0044] It can be seen from the figure that the signal-to-noise ratio of the ion mobility spectrum obtained by using the signal averaging method is 34.7, and the resolution is 26.5; the signal-to-noise ratio of the ion mobility spectrum obtained by using the Hadamard transform ion mobility spectrometer with a TP ion gate is 128.1, and the resolution is 26.3; the signal-to-noise ratio of the ion mobility spectrum obtained by using the Hadamard transform ion mobility spectrometer of the present application is 269.3, and the resolution is 31.2. Therefore, the Hadamard transform ion mobility spectrometer with the three-state ion gate provided in the present application can not only obtain ion mobility spectra with high signal-to-noise ratio and high resolution, but also effectively improve the problem of false peaks in the ion mobility spectra, thereby improving the accuracy and reliability of sample detection.

[0045] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A three-state ion gate, characterized in that: The setup in a Hadamard transform ion mobility spectrometer includes: A first grid, a second grid and a third grid are sequentially and discretely arranged along the direction from the reaction zone to the drift zone; A grid voltage control module is connected to the spectrum modulation Hadamard transform gating unit, the first grid, the second grid and the third grid; when the modulation signal output by the spectrum modulation Hadamard transform gating unit is a first level signal, the voltage of the second grid is controlled to be greater than the voltage of the third grid and less than the voltage of the first grid within a first preset time; when the modulation signal is converted from a first level signal to a second level signal, the voltage of the second grid is controlled to be greater than the voltages of the first grid and the third grid within a second preset time; when the modulation signal is a continuous second level signal, the voltage of the second grid is controlled to be less than the voltages of the first grid and the third grid.

2. The three-state ion gate according to claim 1, characterized in that: When the first level signal is a high level signal, the second level signal is a low level signal; when the first level signal is a low level signal, the second level signal is a high level signal.

3. The three-state ion gate according to claim 1, characterized in that: The voltages of the first grid and the third grid are constant, and the voltage of the first grid is greater than the voltage of the third grid.

4. The three-state ion gate according to claim 1, characterized in that: When the modulation signal is a first level signal, the voltage value of the second grid is half of the sum of the voltage values ​​of the first grid and the third grid.

5. The three-state ion gate according to claim 1, characterized in that: The value range of the first preset time is [2 μs, 600 μs]; and / or The value range of the second preset time is [1 μs, 300 μs].

6. The three-state ion gate according to claim 1, characterized in that: The distance between the first grid and the second grid, and the distance between the second grid and the third grid are in the range of [0.5 mm, 5 mm].

7. The three-state ion gate according to claim 1, characterized in that: When the sample to be detected is dimethyl methyl phosphate, the voltage of the first grid is 2100V, and the voltage of the third grid is 2000V; When the modulation signal is a first level signal, the voltage of the second grid is 2050V; When the modulation signal is converted from a first level signal to a second level signal, the voltage of the second grid is 2150V; When the modulation signal is a continuous second level signal, the voltage of the second grid is 1950V.

8. The three-state ion gate according to claim 7, characterized in that: The first preset time is 150 μs; the second preset time is 75 μs.

9. The three-state ion gate according to claim 7, characterized in that: The distance between the first grid and the second grid, and the distance between the second grid and the third grid are 0.5 mm.

10. A Hadamard transform ion mobility spectrometer, characterized in that: The invention comprises a three-state ion gate as described in any one of claims 1 to 9.

Images