Potential well ion mobility tube and control method

Abstract

The application discloses a potential well ion migration tube and a control method. Adjacent conductive electrodes in a migration zone of the ion migration tube are connected in series with a photocoupler, and the photocoupler is in a normally open state, so that an initial migration electric field with uniform distribution of electric field intensity is formed in the migration zone; the photocoupler is controlled to be temporarily closed in sequence from an ion receiving electrode to an ionization source and then opened again, so that a moving potential well with fast migration from the ion receiving electrode to the ionization source and lower electric field intensity than the initial migration electric field intensity is formed in the migration zone, axial size compression correction of ion groups meeting the moving potential well is caused, ion number density is increased, and finally an ion spectrum peak with basically unchanged migration time, narrowed time domain width and enhanced response current intensity is formed in an ion migration spectrum diagram, so that the IMS resolution capability and detection sensitivity are simultaneously improved. The control method of the potential well ion migration tube is simple in operation, can correct the dispersion and broadening of ions with a full mobility K range in the migration zone of the ion migration tube, and is high in universality.

Description

Technical Field

[0001] This invention relates to the ion migration tube, a core component of an ion mobility spectrometer. Specifically, it relates to a potential trap ion migration tube and a control method for correcting the divergence broadening of ions within the full mobility range K of the ion migration region. Background Technology

[0002] Ion mobility spectrometry (IMS) is a pulsed ion cluster separation and detection technique similar to time-of-flight mass spectrometry. It requires periodically opening ion gates to inject ion clusters into the IMS migration region to achieve the separation and detection of target ions. The temporal width and ion number density of ion clusters in the IMS migration region determine the resolution (R) and detection sensitivity of the IMS.

[0003] For the migration region length L and the total voltage of the migration region U d For IMS with a fixed drift gas temperature T, the resolution R is determined by the initial time width w of the ion cluster. inj And the peak broadening of ion cluster migration and diffusion (16k) B Tln2 / eU d ) 1 / 2 (L 2 / KU d The initial time width w of the ion cluster is determined as shown in formula (1). inj When the value is sufficiently small, R is primarily determined by the diffusion broadening term. Therefore, correcting the temporal width of ion clusters in the IMS migration region is an important approach to achieving ultra-high resolution.

[0004]

[0005] Among them, t d w represents the ion migration time. 0.5 w is the full width at half maximum (FWHM) of the ion peak. inj For the ion gate opening time, 16k B Tln2 / eU d is the ion diffusion broadening coefficient.

[0006] Chen et al. (Anal. Chim. Acta, 2019, 1052:96) found that a gradually decreasing non-uniform DC electric field in the spatial domain can reduce the spatial width of ion clusters and increase their ion number density, while an electric field with enhanced temporal jumps can reduce the temporal width of ion clusters and increase their ion current density. Based on these findings, Chen et al. have developed various methods (CN110491765B, CN110828281B, CN112490108B, etc.) to modulate the temporal width and ion number density of initially implanted ion clusters in the IMS migration region, thereby improving IMS resolution and detection sensitivity. However, research on how to correct for the diffusion broadening that occurs during the migration of ion clusters in the IMS migration region is still relatively limited. Summary of the Invention

[0007] This invention discloses a method for controlling a potential trap ion migration tube. A potential trap with an electric field strength lower than the initial migration electric field strength is formed in the migration region of the ion migration tube. The tube is then controlled to migrate rapidly along the direction from the ion receiver to the ion source, causing axial size compression correction of the encountered ion clusters, increasing the ion number density. Ultimately, this results in ion peaks in the ion migration spectrum with a substantially constant migration time, a narrowed time-domain width, and an enhanced response current intensity, achieving a simultaneous improvement in IMS resolution and detection sensitivity.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] An ion migration tube with a potential trap is provided. The ion migration tube is composed of an ion source, an ionization region, an ion gate, a migration region, and an ion receiving electrode arranged coaxially from left to right. The ionization region and the migration region are both cylindrical cavities formed by alternating coaxial stacking of annular insulators and annular electrodes from left to right. The ionization region is circumferentially sealed to the ion source on its left and the ion gate on its right, respectively, through the annular insulator. The migration region is circumferentially sealed to the ion gate on its left and the ion receiving electrode on its right, respectively, through the annular insulator.

[0010] The ion gate is a Bradbury-Neilson ion gate; the ionization region contains N ring insulators and N+1 ring electrodes, where N is a positive integer greater than or equal to 2; the migration region contains M ring insulators and M+1 ring electrodes, where M is a positive integer greater than or equal to 2. The M+1 ring electrodes are connected in series via the two electrodes of M optocoupler outputs, i.e., along the direction from left to right from the ion source to the ion receiver, the first and second ring electrodes of the migration region are connected to the two electrodes of the first optocoupler output, the second and third ring electrodes are connected to the two electrodes of the second optocoupler output, and so on, with the (M-1)th and Mth ring electrodes connected to the two electrodes of the (M-1)th optocoupler output, and the Mth and (M+1)th ring electrodes connected to the two electrodes of the Mth optocoupler output. All M optocouplers are initially disconnected. The two electrodes of the input terminals of the optocouplers are connected to the two electrodes of a pulsed current source.

[0011] The voltage divider resistor chain consists of six or more voltage divider resistors connected in series from left to right. The two ends of the voltage divider resistor chain and the connection points between adjacent resistors are electrical connection points. Along the direction from left to right from the ion source to the ion receiving electrode, the ion source, the ring electrode of the ionization region, the ion gate, the ring electrode of the migration region, and the ion receiving electrode are sequentially connected to the electrical connection points of the voltage divider resistor chain. The end of the voltage divider resistor chain closest to the ion source is connected to the high voltage output terminal of the DC high voltage power supply, and the end of the voltage divider resistor chain closest to the ion receiving electrode is connected to the ground voltage output terminal of the DC high voltage power supply and to ground.

[0012] A drift gas inlet is provided on the circumferential sidewall of the migration region adjacent to the ion receiving electrode, a sample gas inlet is provided on the circumferential sidewall of the ionization region adjacent to the ion gate, and a tail gas outlet is provided on the circumferential sidewall of the ionization region adjacent to the ion source.

[0013] The ion source is any ion source that can ionize sample gas molecules under atmospheric pressure conditions;

[0014] M is preferably greater than or equal to 6;

[0015] The end of the voltage divider resistor chain near the ion source is connected to the high voltage output terminal of the DC high voltage power supply, and the end of the voltage divider resistor chain near the ion receiving electrode is connected to the ground voltage output terminal of the DC high voltage power supply and the earth.

[0016] An initial migration electric field with uniformly distributed electric field intensity along the axial direction of the ion migration tube is formed within the migration region;

[0017] At the start of a complete working cycle of the ion gate, i.e., at time t = 0, the first, second, third, ..., M-2, M-1, and Mth optocouplers remain disconnected. An initial migration electric field with a uniform electric field distribution along the ion migration tube axis is maintained within the migration region. The ion gate is briefly opened for t seconds.g After a certain period of time, the ion gate region adjacent to the ionization region is closed. Ions enter the migration region to form initial ion clusters. Ions with different mobility K in the initial ion clusters migrate towards the ion receiving electrode under the drive of the initial migration electric field in the migration region, and form multiple discretely distributed sub-ion clusters.

[0018] At the time of t = t1, t1 > t g The first optocoupler, the second optocoupler, the third optocoupler, ..., the (M-2)th optocoupler and the (M-1)th optocoupler remain open, while the Mth optocoupler is briefly closed. opt During the duration, an Mth potential well is formed at the axial position of the ion migration tube corresponding to the Mth optocoupler within the migration region. The electric field strength along the axial direction of the ion migration tube is lower than the initial migration electric field strength. Sub-ion clusters within the potential well undergo dimensional compression correction along the axial direction of the ion migration tube, resulting in an increase in ion number density. opt After the duration ends, the Mth optocoupler returns to the disconnected state, and the initial migration electric field with uniform electric field intensity along the ion migration tube axis is restored in the migration region, driving the ions in the migration region to migrate towards the ion receiving electrode;

[0019] At the time of t = t2, t2 > t1 + t opt The first optocoupler, the second optocoupler, the third optocoupler, ..., the (M-2)th optocoupler and the Mth optocoupler remain in the open state, while the (M-1)th optocoupler is briefly closed. opt During the duration, at the axial position of the ion migration tube corresponding to the (M-1)th optocoupler within the migration region, an (M-1)th ion enrichment trap is formed with an electric field strength along the axial direction of the ion migration tube lower than the initial migration electric field strength. Sub-ion clusters within the ion enrichment trap undergo dimensional compression correction along the axial direction of the ion migration tube, resulting in an increase in ion number density. opt After the duration ends, the M-1 optocoupler returns to the disconnected state, and the initial migration electric field with uniform electric field intensity along the ion migration tube axis is restored in the migration region, driving the ions in the migration region to migrate towards the ion receiving electrode.

[0020] ...;

[0021] At the time of timing t=t M-1 , t M-1 >t M-2 +t opt The first optocoupler, the third optocoupler, ..., the (M-2)th optocoupler, the (M-1)th optocoupler, and the Mth optocoupler remain open, while the second optocoupler is briefly closed. opt During the duration, a second ion enrichment trap is formed at the axial position of the ion migration tube corresponding to the second optocoupler within the migration region. The electric field strength along the axial direction of the ion migration tube is lower than the initial migration electric field strength. Sub-ion clusters within the ion enrichment trap undergo dimensional compression correction along the axial direction of the ion migration tube, resulting in an increase in ion number density. optAfter the duration ends, the second optocoupler returns to the disconnected state, and the initial migration electric field with uniform electric field intensity along the ion migration tube axis is restored in the migration region, driving the ions in the migration region to migrate towards the ion receiving electrode.

[0022] At the time of timing t=t M , t M >t M-1 +t opt The second, third, ..., M-2, M-1, and M-th optocouplers remain open, while the first optocoupler is briefly closed. opt During the duration, a first ion enrichment trap is formed at the axial position of the ion migration tube corresponding to the first optocoupler within the migration region. The electric field strength along the axial direction of the ion migration tube is lower than the initial migration electric field strength. Sub-ion clusters within the ion enrichment trap undergo dimensional compression correction along the axial direction of the ion migration tube, resulting in an increase in ion number density. opt After the duration ends, the first optocoupler returns to the disconnected state, and the initial migration electric field with uniform electric field intensity along the ion migration tube axis is restored in the migration region, driving the ions in the migration region to migrate towards the ion receiving electrode.

[0023] At the time of timing t=t M+1 , t M+1 >t M +t opt The first, second, third, ..., M-2, M-1 and M optocouplers remain disconnected, and the initial migration electric field with uniform electric field intensity along the ion migration tube axis is maintained in the migration region. This drives all sub-ion clusters in the migration region to migrate toward the ion receiving electrode and be detected, forming multiple ion spectral peaks with narrow time-domain width and strong response current intensity in the same ion migration spectrum.

[0024] t opt The optocoupler closing time is defined as the potential trap application time; the timing interval is from t=0 to t=t. F The duration between them is one complete spectrum sampling period of the ion migration tube; M optocouplers are timed according to the timing times t=0, t=t1, t=t2, ..., t=t M-1 , t = t M , t = t M+1 It operates in a time-series periodic cycle.

[0025] The potential trap ion migration tube control method disclosed in this invention involves connecting adjacent conductive electrodes in series with an optocoupler within the migration region of the ion migration tube. The optocoupler is normally open, and an initial migration electric field with uniformly distributed electric field intensity is formed within the migration region. By controlling the optocoupler to briefly close sequentially along the direction from the ion acceptor to the ion source and then reopen it, a potential trap with a rapidly migrating electric field intensity lower than the initial migration electric field intensity can be formed within the migration region. This causes ion clusters that encounter the trap to undergo axial size compression correction, increasing the ion number density. Ultimately, this results in an ion spectral peak in the ion migration spectrum with a migration time that remains essentially constant, a narrower time domain width, and an enhanced response current intensity, achieving a simultaneous improvement in IMS resolution and detection sensitivity.

[0026] The advantages of this invention are:

[0027] The potential trap ion migration tube control method disclosed in this invention utilizes a potential trap that migrates rapidly along the direction from the ion acceptor to the ionization source. This method can correct the divergence and broadening of ions in the full mobility range K within the migration region of the ion migration tube. It is simple to operate and has strong universality.

[0028] The present invention will now be described in further detail with reference to the accompanying drawings: Attached Figure Description

[0029] Figure 1 A cross-sectional view of the ion migration tube in the potential trap ion migration tube control method disclosed in this invention. Wherein: 1, ion source; 2, ionization region; 3, ion gate; 4, migration region; 5, ion receiving electrode; 6, drift gas inlet; 7, sample gas inlet; 8, gas outlet; 9, optocoupler; 10, voltage divider resistor chain.

[0030] Figure 2 (a) Characteristics of the distribution of isopotential lines in the migration region under the initial condition that all optocouplers are disconnected; (b)-(d) Characteristics of the change in the distribution of isopotential lines in the migration region when the optocouplers are briefly closed sequentially along the direction from the ion receiver electrode 5 to the ion source 1.

[0031] Figure 3 (a) Initial migration electric field distribution characteristics in the migration region under the initial condition that all optocouplers are disconnected; (b)-(d) Change characteristics of migration electric field distribution in the migration region when optocouplers are briefly closed sequentially along the direction from ion receiver 5 to ion source 1.

[0032] Figure 4 (a) An ion migration spectrum of 10 ppb dimethyl methyl phosphate was obtained under the initial condition that all optical couplers were disconnected; (b) An ion migration spectrum of 10 ppb dimethyl methyl phosphate was obtained when the optical couplers were briefly closed sequentially along the direction from ion receiver 5 to ion source 1. Detailed Implementation

[0033] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way. The invention will now be described in further detail with reference to the accompanying drawings.

[0034] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0035] An ion migration tube with a potential trap is provided. The ion migration tube is composed of an ion source 1, an ionization region 2, an ion gate 3, a migration region 4 and an ion receiving electrode 5 arranged coaxially from left to right. The ionization region 2 and the migration region 4 are both cylindrical cavities formed by alternating coaxial stacking of annular insulators and annular electrodes from left to right. The ionization region 2 is circumferentially sealed to the ion source 1 located on its left and the ion gate 3 located on its right, respectively, through the annular insulator. The migration region 3 is circumferentially sealed to the ion gate 3 located on its left and the ion receiving electrode 5 located on its right, respectively, through the annular insulator.

[0036] Ion gate 3 is a Bradbury-Neilson ion gate; ionization region 2 contains 4 ring insulators and 5 ring electrodes; migration region 4 contains 11 ring insulators and 12 ring electrodes. The 12 ring electrodes are connected in series via the two electrodes of the output terminals of 11 optocouplers 9. That is, along the direction from left to right from ion source 1 to ion receiver 5, the first and second ring electrodes of migration region 4 are connected to the two electrodes of the output terminal of the first optocoupler, the second and third ring electrodes are connected to the two electrodes of the output terminal of the second optocoupler, and so on. The 10th and 11th ring electrodes are connected to the two electrodes of the output terminal of the 10th optocoupler, and the 11th and 12th ring electrodes are connected to the two electrodes of the output terminal of the 11th optocoupler. All 11 optocouplers 9 are initially disconnected. The two electrodes of the input terminal of optocoupler 9 are connected to the two electrodes of a pulse current source.

[0037] The voltage divider resistor chain 10 is composed of 19 equal voltage divider resistors connected in series from left to right. The two ends of the voltage divider resistor chain 10 and the connection points between adjacent resistors are electrical connection points. Along the direction from left to right from ion source 1 to ion receiving electrode 5, the ion source 1, the annular electrode of ionization region 2, ion gate 3, the annular electrode of migration region 4 and ion receiving electrode 5 are connected to the electrical connection points of the voltage divider resistor chain 10 in sequence. The end of the voltage divider resistor chain 10 near ion source 1 is connected to the high voltage output terminal of the DC high voltage power supply, and the end of the voltage divider resistor chain 10 near ion receiving electrode 5 is connected to the ground voltage output terminal of the DC high voltage power supply and the earth.

[0038] A drift gas inlet 6 is provided on the circumferential sidewall of the migration region 4 adjacent to the ion receiving electrode 5, a sample gas inlet 7 is provided on the circumferential sidewall of the ionization region 2 adjacent to the ion gate 3, and a tail gas outlet 8 is provided on the circumferential sidewall of the ionization region 2 adjacent to the ion source 1; the ion source 1 is a photoionization source based on a 10.6eV VUV Kr lamp.

[0039] The voltage divider resistor chain 10 is connected to the high voltage output terminal of the DC high voltage power supply at one end near the ion source 1, and to the ground voltage output terminal of the DC high voltage power supply and the ground at the other end near the ion receiving electrode 5; thus forming an initial migration electric field with a uniform electric field intensity along the axial direction of the ion migration tube in the migration region 4.

[0040] t opt =50μs is the closing time of optocoupler 9, defined as the potential trap action time; the timing interval is from t=0 to t=t. M+1 The duration between 12ms is 12ms, which is one complete spectrum sampling period of the ion migration tube; the 11 optocouplers are timed according to the timing times t=0, t=t1=1ms, t=t2=2ms, ..., t=t M-1 =10ms, t=t M =11ms, t=t M+1 =12ms timing cycle operation.

[0041] Example 1

[0042] This invention discloses a cross-sectional view of the ion migration tube in the potential trap ion migration tube control method. The ion source 1 of the ion migration tube is a 10.6 eV VUV photoionization source; the ion gate 3 is a Bradbury-Neilsen type ion gate with an opening time of 50 μs and a working cycle of 20 ms; the ion receiving electrode 5 is a Faraday disk with a diameter of 6 mm, fixed on a metal shielding cylinder with an outer diameter of 30 mm; both the ionization region 2 and the migration region 4 are composed of alternating stacked annular conductive electrode sheets with a thickness of 1 mm, an inner diameter of 20 mm, and an outer diameter of 30 mm, and annular insulating electrode sheets with a thickness of 4 mm, an inner diameter of 20 mm, and an outer diameter of 30 mm. The ionization region 2 contains 5 annular conductive electrode sheets, and the migration region 4 contains 12 annular conductive electrode sheets; along the direction from the ion source 1 to the ion receiving electrode 5, the first and second annular conductive electrode sheets of the migration region 4 are connected to the first optocoupler 9 (…). The first optocoupler, the second optocoupler, the third optocoupler, the tenth optocoupler, the eleventh optocoupler, and the eleventh optocoupler are connected to the eleventh optocoupler. Initially, the first optocoupler, the second optocoupler, the tenth optocoupler, and the eleventh optocoupler are all disconnected. The shielding cylinders of the ion source 1, the annular optocoupler 6, the ion gate 3, and the ion receiving electrode 5 are electrically connected to the high-voltage output terminal of the high-voltage power supply and the ground through a voltage divider resistor chain 10 composed of 19 2MΩ resistors connected end to end. The output value of the high-voltage power supply is 7600V, forming an initial migration electric field of 800V / cm in the migration region 4.

[0043] The temperature of the ion migration tube is set to 100℃. The bleaching gas is purified air at a flow rate of 100 mL / min, which enters the ion migration tube through the bleaching gas inlet 6. The dopant gas used in the ion source 1 is acetone at 1 ppm prepared with purified air, with a flow rate of 50 mL / min. The sample gas is a target analyte gas at a specific concentration prepared with purified air, with a flow rate of 50 mL / min. When a sample is being detected, the dopant gas and the sample gas enter the ionization zone 2 of the ion migration tube together through the sample gas inlet 7, and then flow out of the ion migration tube through the tail gas outlet 8 together with the bleaching gas that flows out of the migration zone 4 through the ion gate 3. When no sample is being detected, only the dopant gas enters the ionization zone 2 of the ion migration tube through the sample gas inlet 7, and then flows out of the ion migration tube through the tail gas outlet 8 together with the bleaching gas that flows out of the migration zone 4 through the ion gate 3.

[0044] Figure 2 A illustrates the equipotential line distribution characteristics within the migration region under the initial condition that all optocouplers are disconnected. Clearly, a uniform equipotential line distribution forms within the migration region, corresponding to an initial migration electric field with a uniform distribution and an axial electric field strength of 800 V / cm, as shown in Figure 1. Figure 3 As shown in a; under these conditions, the ion migration spectrum of 10 ppb dimethyl methyl phosphate was obtained as shown in Figure a. Figure 4 As shown in figure a, the signal intensity of the acetone ion peak is ~200 pA, and the full width at half maximum (WWHM) is w. 1 / 2 The migration time is ~100 μs, t d The resolution is 5.67 ms, corresponding to a resolution of R = t d / w 1 / 2 = ~57; the signal intensity of the dimethyl methyl phosphate ion peak is ~80 pA, and the full width at half maximum (WWHM) is w. 1 / 2 The migration time is ~90 μs, t d The resolution is 7.53 ms, corresponding to a resolution of R = t d / w 1 / 2 =~83;

[0045] Figure 2 The diagram illustrates the changing characteristics of the isopotential line distribution within the migration region when the optocoupler is briefly closed sequentially along the direction from the ion receiver 5 to the ion source 1. Clearly, the region with decreasing isopotential line density gradually migrates along the direction from the ion receiver 5 to the ion source 1. Correspondingly, potential wells with local migration electric field strength lower than the initial migration electric field strength gradually migrate along the same direction, as shown in the diagram. Figure 3 As shown in bd. To demonstrate the effect of this fast potential trap, using the opening time of ion gate 3 as a reference time, the optocoupler was briefly closed for 10us along the direction from ion receiver 5 to ion source 1 with a 1ms delay interval, and then reopened. The ion migration spectrum of the doped reagent acetone was obtained as shown in the figure. Figure 4 As shown in b, the signal intensity of the acetone ion peak is ~600 pA, and the full width at half maximum (WWHM) is w. 1 / 2 The migration time is ~50 μs, t d The resolution is 5.67 ms, corresponding to a resolution of R = t d / w 1 / 2 = ~114; the signal intensity of the dimethyl methyl phosphate ion peak is ~140 pA, and the full width at half maximum (WWHM) is w. 1 / 2 The migration time is ~65 μs, t d The resolution is 7.53 ms, corresponding to a resolution of R = t d / w 1 / 2 =~115.

[0046] Figure 4 a and Figure 4 The comparison of results in b clearly demonstrates that the potential trap ion migration tube control method disclosed in this invention has the function of correcting the divergence broadening of ions in the full mobility range K within the migration region.

Claims

1. A potential trap ion migration tube, the ion migration tube comprising an ion source (1), an ionization region (2), an ion gate (3), a migration region (4), and an ion receiving electrode (5) arranged coaxially from left to right, wherein the ionization region (2) and the migration region (4) are both cylindrical cavities formed by alternating coaxial stacking of annular insulators and annular electrodes from left to right, the ionization region (2) being circumferentially sealed to the ion source (1) on its left and the ion gate (3) on its right, respectively, and the migration region (4) being circumferentially sealed to the ion gate (3) on its left and the ion receiving electrode (5) on its right, respectively, characterized in that: Ion gate (3) is a Bradbury-Neilson ion gate; ionization region (2) contains N ring insulators and N+1 ring electrodes, where N is a positive integer greater than or equal to 2; migration region (4) contains M ring insulators and M+1 ring electrodes, where M is a positive integer greater than or equal to 2. Among them, the M+1 ring electrodes are connected in series through the two electrodes of the output terminals of M optocouplers (9), that is, along the direction from left to right from ion source (1) to ion receiver (5), the first ring of migration region (4) The first and second ring electrodes are connected to the two electrodes of the first optocoupler output terminal, the second and third ring electrodes are connected to the two electrodes of the second optocoupler output terminal, ..., the (M-1)th and Mth ring electrodes are connected to the two electrodes of the (M-1)th optocoupler output terminal, the Mth and (M+1)th ring electrodes are connected to the two electrodes of the Mth optocoupler output terminal, and all M optocouplers (9) are initially disconnected; the two electrodes of the input terminal of the optocoupler (9) are connected to the two electrodes of a pulse current source. The voltage divider resistor chain (10) is composed of more than 6 voltage divider resistors connected in series from left to right. The two ends of the voltage divider resistor chain (10) and the connection points between adjacent resistors are electrical connection points. Along the direction from left to right from the ion source (1) to the ion receiving electrode (5), the ion source (1), the ring electrode of the ionization region (2), the ion gate (3), the ring electrode of the migration region (4) and the ion receiving electrode (5) are connected to the voltage divider resistor chain (10) in sequence. The end of the voltage divider resistor chain (10) near the ion source (1) is connected to the high voltage output terminal of the DC high voltage power supply, and the end of the voltage divider resistor chain (10) near the ion receiving electrode (5) is connected to the ground voltage output terminal of the DC high voltage power supply and the earth.

2. The potential trap ion migration tube according to claim 1, characterized in that: A drift gas inlet (6) is provided on the circumferential sidewall of the migration region (4) adjacent to the ion receiving electrode (5), a sample gas inlet (7) is provided on the circumferential sidewall of the ionization region (2) adjacent to the ion gate (3), and a tail gas outlet (8) is provided on the circumferential sidewall of the ionization region (2) adjacent to the ion source (1).

3. The potential trap ion migration tube according to claim 1, characterized in that: Ion source (1) is any ion source that can ionize sample gas molecules under atmospheric pressure.

4. The potential trap ion migration tube according to claim 1, characterized in that: M is greater than or equal to 6.

5. The potential trap ion migration tube according to claim 1, characterized in that: The voltage divider resistor chain (10) is connected to the high voltage output terminal of the DC high voltage power supply at one end near the ion source (1), and the voltage divider resistor chain (10) is connected to the ground voltage output terminal of the DC high voltage power supply and the ground at the other end near the ion receiving electrode (5). An initial migration electric field with uniformly distributed electric field intensity along the axial direction of the ion migration tube is formed in the migration region (4).

6. A method for controlling the potential trap ion migration tube according to any one of claims 1-5, At the beginning of a complete working cycle of the ion gate (3), i.e., the timing moment t = 0, the first optocoupler, the second optocoupler, the third optocoupler, ..., the M-2nd optocoupler, the M-1st optocoupler and the Mth optocoupler remain disconnected, and the initial migration electric field with a uniform electric field intensity distribution along the ion migration tube axis is maintained in the migration region (4), and the ion gate (3) is briefly opened. t g After a certain period of time, the ionization region (2) is closed, and the ions in the region adjacent to the ion gate (3) enter the migration region (4) to form the initial ion cluster. The mobility within the initial ion cluster is... K Different ions migrate toward the ion receiving electrode (5) under the drive of the initial migration electric field in the migration region (4), and form multiple discretely distributed sub-ion clusters; At the time of the countdown t = t 1, t 1> t g The first optocoupler, the second optocoupler, the third optocoupler, ..., the (M-2)th optocoupler and the (M-1)th optocoupler remain open, while the Mth optocoupler is briefly closed. t opt During the duration, an Mth potential well is formed at the axial position of the ion migration tube corresponding to the Mth optocoupler within the migration region (4). The electric field strength along the axial direction of the ion migration tube is lower than the initial migration electric field strength. Sub-ion clusters in the potential well undergo dimensional compression correction along the axial direction of the ion migration tube, resulting in an increase in ion number density. t opt After the duration ends, the Mth optocoupler returns to the disconnected state, and the initial migration electric field with uniform electric field intensity along the ion migration tube axis is restored in the migration region (4), driving the ions in the migration region (4) to migrate towards the ion receiving electrode (5). At the time of the countdown t = t 2, t 2> t 1+ t opt The first optocoupler, the second optocoupler, the third optocoupler, ..., the (M-2)th optocoupler and the Mth optocoupler remain disconnected, while the (M-1)th optocoupler is briefly closed. t opt During the duration, an M-1 ion enrichment trap is formed at the axial position of the ion migration tube corresponding to the M-1th optocoupler within the migration region (4). The electric field strength along the axial direction of the ion migration tube is lower than the initial migration electric field strength. Sub-ion clusters in the ion enrichment trap undergo dimensional compression correction along the axial direction of the ion migration tube, resulting in an increase in ion number density. t opt After the duration ends, the M-1 optocoupler is disconnected again, and the initial migration electric field with uniform electric field intensity along the ion migration tube axis is restored in the migration region (4), driving the ions in the migration region (4) to migrate towards the ion receiving electrode (5). At the time of the countdown t = t M-1 , t M-1 > t M-2 + t opt The first optocoupler, the third optocoupler, ..., the (M-2)th optocoupler, the (M-1)th optocoupler, and the Mth optocoupler remain disconnected, while the second optocoupler is briefly closed. t opt During the duration, a second ion enrichment trap is formed at the axial position of the ion migration tube corresponding to the second optocoupler within the migration region (4). The electric field strength along the axial direction of the ion migration tube is lower than that of the initial migration electric field strength. Sub-ion clusters in the ion enrichment trap undergo dimensional compression correction along the axial direction of the ion migration tube, and the ion number density increases. t opt After the duration ends, the second optocoupler returns to the disconnected state, and the initial migration electric field with uniform electric field intensity along the ion migration tube axis is restored in the migration region (4), driving the ions in the migration region (4) to migrate towards the ion receiving electrode (5). At the time of the countdown t = t M , t M > t M-1 + t opt The second, third, ..., M-2, M-1, and Mth optocouplers remain open, while the first optocoupler is briefly closed. t opt During the duration, a first ion enrichment trap is formed at the axial position of the ion migration tube corresponding to the first optocoupler within the migration region (4). The electric field strength along the axial direction of the ion migration tube is lower than the initial migration electric field strength. Sub-ion clusters in the ion enrichment trap undergo dimensional compression correction along the axial direction of the ion migration tube, and the ion number density increases. t opt After the duration ends, the first optocoupler returns to the disconnected state, and the initial migration electric field with uniform electric field intensity along the ion migration tube axis is restored in the migration region (4), driving the ions in the migration region (4) to migrate towards the ion receiving electrode (5). At the time of the countdown t = t M+1 , t M+1 > t M + t opt The first optical coupler, the second optical coupler, the third optical coupler, ..., the M-2 optical coupler, the M-1 optical coupler and the M optical coupler remain disconnected. The initial migration electric field with uniform electric field intensity along the axial direction of the ion migration tube is maintained in the migration region (4), driving all sub-ion clusters in the migration region (4) to migrate toward the ion receiving electrode (5) and be detected, forming multiple ion spectral peaks with narrow time domain width and strong response current intensity in the same ion migration spectrum.

7. The control method for the potential trap ion migration tube according to claim 6, characterized in that: t opt The closing time of the optocoupler (9) is defined as the time of action of the potential trap; Countdown t = 0 to t = t M+1 The duration between them is one complete spectrum sampling period of the ion migration tube; M optocouplers (9) are timed according to the timing time. t = 0、 t = t 1. t = t 2、......、 t = t M-1 , t = t M , t = t M+1 It operates in a time-series periodic cycle.

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