Ion mobility spectrometer and method of analysis based on lateral migration

Abstract

The present application belongs to the technical field of gas analyzer, and particularly relates to an ion mobility spectrometry analyzer based on lateral migration and an analysis method. In view of the problem that the effective migration distance of the existing gas absorption type ion mobility spectrometer is limited by the channel thickness, resulting in low resolution, the present application provides an analyzer comprising upper and lower plates and an analyzer channel, the upper and lower plates are provided with pairs of migration electrodes arranged along the width direction of the channel to form a lateral migration electric field; a local ionization region and a detection region are arranged in the channel. The ions to be measured move along the length direction of the analyzer along with the airflow, migrate along the width direction under the action of the lateral electric field, and are detected under the action of the deflection electric field after reaching the detection region. The present application changes the migration direction to the width direction, greatly increases the effective migration distance, improves the resolution, and is compatible with the planarization process, which is beneficial to miniaturization.

Description

Technical Field

[0001] This invention belongs to the field of gas analyzer technology, specifically relating to an ion mobility spectrometer based on lateral migration and its application method. Background Technology

[0002] Ion mobility spectrometry (IMP) is a technique for separating, identifying, and analyzing substances based on the differences in migration rates of gaseous ions in an electric field and a buffer gas under ambient or near-ambient pressure. After being ionized by photoionization, corona discharge, radioactive source ionization, chemical ionization, or other methods, the analyte migrates under the influence of an electric field. Because different ions have different mobilities, qualitative or quantitative analysis of the analyte can be achieved through drift time, spatial location, voltage response, or mobility spectra. An IMP analyzer typically consists of a sample introduction unit, ionization source, migration analysis region, electric field generation unit, detector, power supply, and signal processing unit. The migration analysis region, its electric field, gas flow, and detection structure constitute the core of the IMP analyzer. Ion mobility spectrometers offer advantages such as fast response, high sensitivity, operation at ambient pressure, and suitability for on-site detection, and are widely used in fields such as explosives and narcotics detection, environmental monitoring, industrial process control, food safety, breath analysis, chemical leak alarms, and volatile organic compound detection. With the development of on-site online detection, unmanned platform deployment, distributed sensor networks, and MEMS technology, ion mobility spectrometers and their core analyzers are evolving towards portability, low power consumption, low cost, and online integration.

[0003] Among various miniaturized ion mobility spectrometry (IMP) techniques, gas-driven IMP exhibits high miniaturization potential due to its simple structure, lack of traditional ion gates and long drift tubes, absence of high-frequency, high-voltage asymmetric waveform power supplies, ease of planarization, and low-power integration. Gas-driven IMP typically introduces sample gas into a flat channel via suction, pressure differential, micro-pumping, or carrier gas transport, achieving ion spatial separation under the combined influence of laminar gas flow and an electrostatic field. In a typical structure, the sample gas flows along the length of the flat channel, and ions migrate from one side of the channel surface to the other under the influence of an electric field perpendicular to the gas flow direction. Ions with different mobilities reach the detection surface at different times, forming different spatial positions along the flow direction, thus achieving separation and detection. However, the primary migration direction in existing gas-driven IMP is usually along the thickness of the flat channel. To maintain device flatness, flow field stability, electric field uniformity, and planar fabrication compatibility, the channel thickness is typically much smaller than the channel width and length, resulting in the effective migration distance of ions in the thickness direction being limited by the channel height. Because of the short effective migration distance, the spatial peak position difference formed by ions with different mobility rates is small. This is easily on the same order of magnitude as ion diffusion broadening, initial ion cloud width, uneven flow field distribution, detection electrode size, and electric field edge effect, resulting in spectral peak overlap, low resolution, and insufficient recognition ability. This limits the application of gas-breathing ion mobility spectroscopy in the identification of complex gas components and high-resolution online detection.

[0004] To address the aforementioned issues, existing technologies have attempted to improve ion collection efficiency and spatial separation by modifying electrode structures, optimizing sample introduction methods, incorporating getter condensers, altering channel geometry, adding ion aggregation structures, or adjusting gas flow and electric field distribution. For example, patent application CN101853771A discloses an improved getter condenser structure ion mobility spectrometer. By incorporating auxiliary integrated detector electrodes, counting electrodes, integrated detector electrodes, and auxiliary electrodes, it improves ion collection and detection sensitivity to some extent, but still fails to address the low resolution problem. Patent application US20070023647A1 discloses an ion mobility spectrometer with parallel drift gas flow and ion carrier gas flow. By confining the ion-containing carrier gas flow to a smaller area of ​​the separation zone cross-section and utilizing a nearly ion-free drift gas flowing in the same direction, ions enter the analysis zone from a narrower and relatively defined position, thereby reducing peak broadening caused by differences in initial position and flow rate, and improving spatial separation accuracy. However, this scheme requires precise control of multiple airflows, is susceptible to flow fluctuations and airflow diffusion, and its main function is to reduce the peak width. The migration direction and effective migration distance of ions have not changed and are still limited by the thickness of the flat channel, making it difficult to fundamentally increase the spatial peak position difference of ions with different mobilities.

[0005] Most of the aforementioned methods still primarily achieve migration and separation along the thickness direction of the flat channel, and their effective migration distance is essentially limited by the channel thickness. Directly increasing the channel thickness to increase the effective migration distance may lead to increased required voltage, decreased electric field uniformity, worsened flow field stability, increased device size, and increased difficulty in planar fabrication. Conversely, increasing the field strength by reducing the channel width or altering the local structure may result in enhanced edge electric field, increased ion wall loss, and decreased detection repeatability. Therefore, there is an urgent need to develop an ion mobility spectrometer that can address the problems of insufficient spatial separation capability and low resolution caused by the fact that ions mainly migrate along the thickness direction of the flat channel in existing gas-driven ion mobility spectrometry, and that the effective migration distance is limited by the channel height. Summary of the Invention

[0006] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides an ion mobility spectrometer based on lateral migration. This analyzer increases the effective migration separation distance by enabling ions to migrate laterally along a flat channel during gas flow transport, thereby improving the ion spatial separation capability of the gas-feeding ion mobility spectrometer structure and raising the upper limit of resolution.

[0007] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides an ion mobility spectrometry analyzer based on lateral migration, comprising: Analyzer channel, upper electrode, lower electrode, migration electrode, local ionization region, and detection region; The length direction of the analyzer channel, i.e. the flow direction of the gas and detected ions, is defined as the X-axis, the width direction as the Y-axis, and the thickness direction as the Z-axis. The upper and lower plates are provided with a plurality of migration electrodes, which are arranged at equal intervals along the Y-axis direction. A gradient voltage is applied between adjacent migration electrodes to form a lateral migration electric field along the Y-axis direction in the analyzer channel. The two ends of the local ionization region are ionization windows provided on the upper and lower electrodes, and the local ionization region extends through the analyzer channel along the Z-axis direction; further, an ionization source is provided or directly opposite the local ionization region for ionizing the analyte to generate ions; The detection area includes a deflection electrode disposed on the lower electrode plate and a detection electrode disposed on the upper electrode plate; the detection electrode is a single fixed detection electrode and detection auxiliary electrodes located on both sides of the single fixed detection electrode; or, the detection electrode is a multi-channel array detection electrode. The deflection electrode is used to apply a deflection voltage to form a deflection electric field along the Z-axis direction. The single fixed detection electrode has a potential of 0 and is used to detect the target ion signal. The detection auxiliary electrode is grounded and is used to collect and absorb ions other than the target ion to reduce interference with the target ion. The multi-channel array detection electrode includes multiple independent electrodes for detecting target ion signals at multiple different positions along the X-flow direction. Furthermore, the migration electrode is a rectangular electrode, placed parallel to and overlapping the channel surface, with its long side parallel to the X-axis and its short side parallel to the Y-axis; the migration electrodes on the upper and lower plates are parallel to each other and their projections on the XY plane completely overlap, forming a pair of vertically parallel migration electrodes.

[0008] Furthermore, the distance from the local ionization region to the single fixed detection electrode along the Y-axis direction is 10 to 30 times the thickness of the analyzer channel; Furthermore, the greater the distance from the local ionization region along the Y-axis to the single fixed detection electrode, the greater the increase in effective migration distance. However, due to the diffusion effect, the benefit of increasing migration distance on improving resolution tends to stabilize. At the same time, as the effective migration distance becomes too long, although the resolution is improved, the sensitivity also decreases. Therefore, the overall performance is optimal when the distance from the local ionization region along the Y-axis to the single fixed detection electrode is 10 to 30 times the thickness of the analyzer channel, but in actual use, it is not limited to this range.

[0009] Furthermore, each independent electrode included in the deflection electrode, detection auxiliary electrode, single fixed detection electrode, and multi-channel array detection electrode is a rectangular electrode with its long side parallel to the X-axis, its short side parallel to the Y-axis, and all parallel to and overlapping with the channel surface. Furthermore, the projection of the deflection electrode in the XY plane covers the projection of the detection electrode; Furthermore, the projection of the deflection electrode in the XY plane covers the projections of the detection auxiliary electrode and the single fixed detection electrode; or, the projection of the deflection electrode in the XY plane covers the projection of the multi-channel array detection electrode. Furthermore, the local ionization region is provided with a local ionization window, which is a circular hole or a slit, used to restrict the initial position of ions in the width direction.

[0010] Furthermore, the width of the analyzer channel is greater than its thickness; Furthermore, the analyzer channel is made of PCB, glass, silicon, quartz, ceramic or polymer materials; furthermore, the analyzer channel is integrally formed using a multilayer PCB.

[0011] Secondly, the present invention provides an ion mobility spectrometry analysis method based on lateral migration, applied to the ion mobility spectrometry analyzer based on lateral migration described in the first aspect, comprising the following steps: S1. Sample introduction and ionization: The analyte flows along the X-axis of the analyzer channel with the carrier gas. When it flows through the local ionization region, the analyte is ionized to generate ions. S2, Lateral migration separation: While the ions move along the X-axis with the airflow, they generate an electric field migration velocity along the Y-axis under the action of the lateral migration electric field formed by the upper and lower electrode migration electrodes, thereby realizing the spatial separation of ions with different mobility. S3. Deflection and Detection: The spatially separated ions move to the detection area and are deflected along the Z-axis under the action of the deflection electric field formed by the deflection electrode and the detection electrode. The ions are collected by the detection electrode and converted into a current signal.

[0012] Furthermore, when the spatial separation of ions with different mobilities is performed using a scanning voltage mode, the detection electrode consists of a single fixed detection electrode and detection auxiliary electrodes located on both sides of the single fixed detection electrode. The method includes the following steps: The position of the single fixed detection electrode is kept fixed, and the gradient voltage of the transverse migration electric field is scanned according to a preset sequence. Under the action of the deflection electric field in the Z-axis direction formed by the deflection electrode, the single fixed detection electrode, and the detection auxiliary electrode, the ions move towards the single fixed detection electrode or the detection auxiliary electrode. The target ions that reach the detection auxiliary electrode are annihilated, and the target ions that reach the single fixed detection electrode are detected and a current signal is generated. The current signals under different gradient voltages are recorded to form a current-voltage signal spectrum, thereby realizing the separation, detection, and identification of specific ions.

[0013] Furthermore, when the spatial separation of ions with different mobilities is detected using a fixed voltage mode, the detection electrode is a multi-channel array detection electrode, which includes multiple independent electrodes for detecting target ion signals at multiple different positions along the X-axis. The method includes the following steps: By keeping the gradient voltage of the transverse migration electric field fixed, the target ion moves towards the multi-channel array detection electrode under the action of the deflection electric field in the Z-axis direction formed by the deflection electrode and the multi-channel array detection electrode. The target ions that reach the multi-channel array detection electrode fall onto the independent electrodes at different spatial positions in the multi-channel array detection electrode, are detected, and generate current signals, thereby synchronously acquiring the spatial distribution spectrum of ions with different mobility rates, and realizing the separation, detection and identification of ions with different mobility rates.

[0014] Thirdly, the present invention provides an ion mobility spectrometer, including the lateral migration-based ion mobility spectrometer described in the first aspect, and a control unit and a signal processing unit for controlling the operation of the analyzer.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention changes the main migration direction of ions from the channel thickness direction to the channel width direction (lateral). While maintaining the channel flattening (small thickness), it significantly increases the effective migration and separation distance of ions, thereby effectively improving the spatial peak position difference of ions with different mobilities and significantly improving the spectral resolution; at the same time, it avoids the problems of increased driving voltage, decreased electric field uniformity and flow field instability caused by directly increasing the channel thickness.

[0016] 2. By using planar electrode arrays on the upper and lower plates to synthesize the lateral migration electric field, there is no need for traditional ion gates and long drift tubes. This structure is fully compatible with standard planar micromachining processes such as MEMS and PCB, making it easy to achieve miniaturization, on-chip integration, low power consumption, and mass production of the analyzer.

[0017] 3. By setting local ionization windows (such as circular holes or slits), the initial position of ions in the lateral migration direction is strictly limited, which effectively reduces the adverse effect of the initial ion cloud width on spatial resolution and further ensures high-resolution separation.

[0018] 4. Based on the lateral migration structure, this invention provides two spatiotemporally equivalent detection modes: (1) Scanning voltage mode: using a single fixed detection electrode in conjunction with voltage scanning, requiring only a single-channel signal processing circuit, with extremely low hardware complexity and cost, suitable for prototypes and low-cost portable instruments; (2) Fixed voltage mode: using a multi-channel array detection electrode, without voltage scanning, it can output spatial ion migration spectra in real time and in parallel, suitable for simultaneous detection of multiple components and rapid response scenarios. Both modes make full use of the long effective distance brought by lateral migration, achieving high-resolution detection.

[0019] 5. When the present invention employs scanning voltage mode, the detection area forms a deflection electric field through the deflection electrode and the grounded auxiliary detection electrode. This field guides the target ions to a single fixed detection electrode while simultaneously annihilating non-target ions that deviate from the trajectory on the auxiliary detection electrode. This structure achieves effective spatial filtering, eliminates stray ion interference, and significantly improves the signal-to-noise ratio of the detection signal. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overall structure of an analyzer that uses a single fixed detection electrode and a detection auxiliary electrode; Figure 2 This is a structural diagram of the upper and lower plates of an analyzer that uses a single fixed detection electrode and a detection auxiliary electrode. Figure 3 This is a structural diagram of the upper and lower plates of an analyzer employing a multi-channel array detection electrode. Figure 4 A top-view schematic diagram of ion lateral migration and separation within the analyzer; Figure 5 This is a side view of the lateral migration electric field inside the analyzer; Figure 6 This is a structural diagram of a PCB-based lateral migration ion mobility spectrometer. Figure 7 The analyzer scans the voltage detection signal spectrum.

[0022] Wherein, 1-Analyzer channel; 2-Upper electrode migration electrode; 3-Lower electrode migration electrode; 4-Local ionization region; 5-Deflection electrode; 6-First detection auxiliary electrode; 7-Second detection auxiliary electrode; 8-Single fixed detection electrode; 9-Analyzer upper electrode; 10-Analyzer lower electrode; 11-Multi-channel array detection electrode; 12-Gas path inlet; 13-Gas path outlet; 14-Local ionization window; 15-Top electrode region; 16-Bottom electrode region; 17-Upper electrode; 18-Lower electrode; 19-Support layer. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0024] This invention provides an ion mobility spectrometer based on lateral migration, such as... Figure 1 , Figure 2 As shown, it includes an analyzer channel 1, an upper electrode migration electrode 2, a lower electrode migration electrode 3, a local ionization region 4, a deflection electrode 5, a first detection auxiliary electrode 6, a second detection auxiliary electrode 7, a single fixed detection electrode 8, an upper analyzer plate 9, and a lower analyzer plate 10, wherein, as... Figure 3As shown, the first detection auxiliary electrode 6, the second detection auxiliary electrode 7, and the single fixed detection electrode 8 can be replaced by a multi-channel array detection electrode 11.

[0025] Its core working principle is based on the coupled motion of ions in an electric field and a flow field. If the mobility of an ion is K and the electric field strength of its region is E, then the electric field migration velocity of the ion satisfies the formula V=K. E, the direction is the same as the direction of the electric field.

[0026] Combination Figure 4 As shown, the gas moves at a constant velocity along the X-axis within the analyzer channel, with a flow velocity of u. The analyte is ionized into ions in the local ionization region 4. Taking positive ions as an example... Figure 5 As shown, under the action of a transverse migration electric field E1 along the negative Y-axis, positive ions generate an electric field migration velocity V along the negative Y-axis. y If the analyte ionizes to generate negative ions, the polarity of the migration electric field gradient voltage is reversed by the control unit (making the electric field along the positive Y-axis), and the negative ions will generate an electric field migration velocity V along the negative Y-axis. y This enables the detection of positive and negative ions migrating in the same direction.

[0027] Ions simultaneously participate in motion in two directions within the channel: uniform motion along the X-axis with the airflow (velocity u) and migration along the Y-axis under the influence of a transverse electric field (velocity V). y When ions, starting from the local ionization region 4, have just reached the set value W along the Y direction (i.e., above the detection region) and reached L along the X direction, the ions move between the detection electrode and the deflection electrode. At this time, under the action of the deflection electric field E2 in the Z-axis direction (thickness direction), the ions generate an electric field deflection velocity V. z Moving downwards, it eventually reaches the surface of the detection electrode, where it is collected and generates a current signal.

[0028] Example 1: Lateral migration channel structure based on top / bottom planar electrodes This embodiment employs a flat rectangular gas channel. The gas channel length can be 5-100mm, preferably 10-50mm; the width can be 2-50mm, preferably 5-30mm; and the thickness can be 0.1-3mm, preferably 0.5-1mm. The channel width is greater than the channel thickness, allowing for an effective migration distance in the width direction greater than in the thickness direction. The channel material can be a PCB dielectric layer, glass, silicon, quartz, ceramic, LTCC, polymer, or a composite structure thereof.

[0029] Multiple metal electrode strips are arranged at the top and bottom layers of the channel. These strips extend along the channel's length (X-axis) and are arranged along its width (Y-axis). Each electrode strip is connected to a voltage divider resistor network, a multi-channel DAC, a high-voltage switching matrix, or an adjustable DC power supply, creating a predetermined potential difference between adjacent electrodes. This generates a uniform lateral migration electric field along the width of the channel. To reduce interference from the electric field on the detection electrode signal, protective and shielding electrodes can be placed near the detection electrodes.

[0030] Example 2: Localized Ionization Structure In this embodiment, as Figure 2 , 3 As shown, a local ionization window is provided at the top of the gas channel, through which an ultraviolet light source can be directed to irradiate the interior of the channel. The sample gas mixes with the carrier gas and flows along the length of the channel. Sample molecules are ionized only when they pass through the local ionization region 4, thus strictly constraining the initial position of ions in the width direction (Y-axis) and reducing the impact of the initial ion cloud width on spatial resolution. The ionization window can be a circular aperture or a slit. The diameter of the circular aperture can be 10 μm-2 mm, preferably 50 μm-500 μm; the slit width can be 10 μm-1 mm.

[0031] Example 3: Integrated Analyzer Structure Based on Multilayer PCB This embodiment uses a multilayer PCB integrated fabrication to form the gas path, flat migration channel, and electrode structure of the ion mobility spectrometer. For example... Figure 6As shown, the multilayer PCB includes a top cover plate, a top electrode layer, top and bottom layers of the channel layer, a bottom electrode layer, and a bottom cover plate. The top cover plate and the top electrode layer constitute the upper electrode plate 17, the top and bottom layers of the channel layer constitute the support layer 19, and a rectangular groove is cut out in 19 as an air passage. The bottom cover plate and the bottom electrode layer constitute the lower electrode plate 18. 12 is the air passage inlet, and 13 is the air passage outlet, which is welded to the top cover plate of the channel layer via a metal pipe, and is vented or evacuated by a pump. 15 is the top electrode area, including the top migration electrode, detection electrode, and detection auxiliary electrode; 16 is the bottom electrode area, including the bottom migration electrode and deflection electrode. 14 is a local ionization window (such as a circular hole, slit, or light-transmitting window penetrating the top cover plate) set at a predetermined position, through which the ion source generates ions in a local area of ​​the migration channel. In this multilayer PCB structure, the height of the flat migration channel is limited by the thickness of the intermediate insulating layer, prepreg, or solder mask layer. The top and / or bottom copper foils are patterned as a strip-shaped planar electrode array arranged along the channel width direction, and a gradient voltage is applied through embedded traces, vias, and a voltage divider resistor network to synthesize a transversely migrating electric field. The top electrode area 15 and the bottom electrode area 16 can be connected to a low-current amplifier, shielding box, or coaxial interface via in-board traces to reduce leakage current and external noise. This integrated structure reduces assembly errors, improves channel sealing and prototype repeatability, and facilitates the development of low-cost, mass-producible portable instruments.

[0032] Example 4: Scanning Voltage Detection Mode This embodiment employs a single-point detection structure, meaning the detection area includes a deflection electrode 5, a first auxiliary detection electrode 6, a second auxiliary detection electrode 7, and a single fixed detection electrode 8 located between them. The single fixed detection electrode 8 is positioned at a predetermined detection location L. In this mode, the displacement W of the ion along the Y direction is fixed. The control unit scans the transverse migration voltage, causing the transverse electric field to change according to a predetermined sequence. Because ions with the same mobility have different electric field migration speeds along the Y direction under different gradient voltages, the migration time required for their displacement W along the Y direction differs, thus causing their displacement along the X direction to change under the same airflow velocity. The specific physical process is as follows: Figure 4As shown, when the applied transverse gradient electric field is large, the ions migrate laterally quickly, requiring a short time to reach the Y-direction displacement W, and have a smaller displacement along the X-direction. The ion trajectory hits the first detection auxiliary electrode 6 (i.e., trajectory A) near the local ionization region, and the ions are annihilated. When the applied transverse gradient electric field is moderate (reaching the peak voltage), the ion trajectory hits the single fixed detection electrode 8 in the middle (i.e., trajectory B), and is detected to form a current signal. When the applied transverse gradient electric field is small, the ions migrate laterally slowly, have a larger displacement along the X-direction, and the ion trajectory hits the second detection auxiliary electrode 7 (i.e., trajectory C) far from the local ionization region, and the ions are annihilated. By scanning the gradient voltage from low to high, the single fixed detection electrode 8 records and forms a current-voltage signal spectrum (e.g., ...). Figure 7 (As shown). In the spectrum, substances with higher ion mobility (such as substance a) and substances with lower ion mobility (such as substance b) correspond to different peak position voltages, thereby achieving separation, detection, and identification. This mode has a small number of individual fixed detection electrodes 8 and weak current amplification channels, making it suitable for prototypes and low-cost instruments.

[0033] Example 5: Fixed Voltage Array Detection Mode This embodiment employs an array detection structure, replacing the single fixed detection electrode 8 and the first and second auxiliary detection electrodes 6 and 7 with a multi-channel array detection electrode 11 arranged along the channel length, width, or a two-dimensional plane. Each independent detection unit of the multi-channel array detection electrode 11 corresponds to the current signal of one channel. In this mode, the transverse gradient voltage remains fixed. Because ions with different mobilities migrate at different electric field speeds along the Y direction under the same fixed gradient voltage, the migration time required for them to move a fixed value W along the Y direction varies. Therefore, ions with different mobilities move differently along the X direction with the airflow under the fixed gradient voltage. Ions with high mobility move less along the X direction and strike the detection unit on the side of the multi-channel array detection electrode 11 closer to the ionization region; ions with low mobility move more along the X direction and strike the detection unit on the side of the multi-channel array detection electrode 11 farther from the ionization region. Ions with different mobilities fall into detection units at different spatial positions in the array, forming current signals for different channels. By synchronously reading the signals of each channel, the spatial distribution spectrum can be directly reconstructed. This mode requires no voltage scanning and can output spatial ion mobility spectra in real time, making it suitable for simultaneous detection of multiple components, rapid response, and spectral imaging.

[0034] Example 6: System Integration and Combined Use Based on the aforementioned lateral migration ion mobility spectrometer, a peripheral gas path control circuit, a high-voltage power supply module, and a weak current amplification and signal processing unit can be integrated to form a complete ion mobility spectrometer system. The complete system, according to Embodiment 4 or Embodiment 5 above, uses a DC power supply scanning voltage or a fixed voltage array detector for detection.

[0035] Furthermore, this analyzer, as a core separation and detection module, can also be used in conjunction with other analytical instruments such as mass spectrometers, other types of ion mobility spectrometers, gas chromatographs, or liquid chromatographs as a front-end pre-separation or orthogonal detection module to enhance the analytical capabilities for complex matrix samples. This analyzer can flexibly achieve scanning voltage detection in both positive and negative ion modes by controlling the magnitude and direction of the gradient voltage.

Claims

1. An ion mobility spectrometry analyzer based on lateral migration, characterized in that, include: Analyzer channel, upper electrode, lower electrode, migration electrode, local ionization region, and detection region; The length direction of the analyzer channel, i.e. the flow direction of the gas and detected ions, is defined as the X-axis, the width direction as the Y-axis, and the thickness direction as the Z-axis. The upper and lower plates are provided with a plurality of migration electrodes, which are arranged at equal intervals along the Y-axis. A gradient voltage is applied between adjacent migration electrodes to form a lateral migration electric field along the Y-axis in the analyzer channel. The two ends of the local ionization region are ionization windows located on the upper and lower electrodes, and the local ionization region extends through the analyzer channel along the Z-axis direction; The detection area includes a deflection electrode disposed on the lower electrode plate and a detection electrode disposed on the upper electrode plate. The deflection electrode is used to apply a deflection voltage to form a deflection electric field along the Z-axis direction.

2. The ion mobility spectrometer based on lateral migration according to claim 1, characterized in that, The detection electrode consists of a single fixed detection electrode and detection auxiliary electrodes located on both sides of the single fixed detection electrode; The single fixed detection electrode has a potential of 0 and is used to detect target ion signals; The detection auxiliary electrode is grounded and used to collect and absorb ions other than the target ions, thereby reducing interference with the target ions.

3. The ion mobility spectrometer based on lateral migration according to claim 1, characterized in that, The detection electrode is a multi-channel array detection electrode; The multi-channel array detection electrode contains multiple independent electrodes for detecting target ion signals at multiple different locations along the X-axis.

4. The lateral migration ion mobility spectrometer according to any one of claims 1 to 3, characterized in that, The migration electrode is a rectangular electrode, placed parallel to and overlapping the analyzer channel surface, with its long side parallel to the X-axis and its short side parallel to the Y-axis; the migration electrodes on the upper and lower plates are parallel to each other and their projections on the XY plane completely overlap, forming a pair of vertically parallel migration electrodes.

5. The lateral migration ion mobility spectrometer according to claim 2, characterized in that, The distance from the local ionization region along the Y-axis to the single fixed detection electrode is 10 to 30 times the thickness of the analyzer channel.

6. The lateral migration ion mobility spectrometer according to any one of claims 1 to 3, characterized in that, The projection of the deflection electrode in the XY plane covers the projection of the detection electrode.

7. A lateral migration-based ion mobility spectrometry analysis method, applied to the lateral migration-based ion mobility spectrometry analyzer according to any one of claims 1 to 6, characterized in that, Including the following steps: The analyte flows along the X-axis of the analyzer channel with the carrier gas, and when it flows through the local ionization region, the analyte is ionized to generate ions; While the ions move along the X-axis with the airflow, they generate an electric field migration velocity along the Y-axis under the action of the transverse migration electric field formed by the upper and lower electrode migration electrodes, thereby achieving spatial separation of ions with different mobility rates. The ions, after spatial separation, move to the detection area and are deflected along the Z-axis under the action of the deflection electric field formed by the deflection electrode and the detection electrode. The ions are collected by the detection electrode and converted into a current signal.

8. The method according to claim 7, characterized in that, When the spatial separation of ions with different mobilities is performed using a scanning voltage mode, the detection electrode consists of a single fixed detection electrode and detection auxiliary electrodes located on both sides of the single fixed detection electrode. The method includes the following steps: The position of the single fixed detection electrode is kept fixed, and the gradient voltage of the transverse migration electric field is scanned according to a preset sequence. Under the action of the deflection electric field in the Z-axis direction formed by the deflection electrode, the single fixed detection electrode and the detection auxiliary electrode, the ions move towards the single fixed detection electrode or the detection auxiliary electrode. The target ions that reach the detection auxiliary electrode are annihilated, and the target ions that reach the single fixed detection electrode are detected to form a current signal. Record the current signals under different gradient voltages to form a current-voltage signal spectrum, and realize the separation, detection and identification of specific ions.

9. The method according to claim 7, characterized in that, When the spatial separation of ions with different mobilities is performed using a fixed voltage mode, the detection electrode is a multi-channel array detection electrode, which includes multiple independent electrodes for detecting target ion signals at multiple different positions along the X-axis. The method includes the following steps: By keeping the gradient voltage of the transverse migration electric field fixed, the target ion moves towards the multi-channel array detection electrode under the action of the deflection electric field in the Z-axis direction formed by the deflection electrode and the multi-channel array detection electrode. The target ions that reach the multi-channel array detection electrode fall onto the independent electrodes at different spatial positions in the multi-channel array detection electrode, are detected, and generate current signals, thereby synchronously acquiring the spatial distribution spectrum of ions with different mobility rates, and realizing the separation, detection and identification of ions with different mobility rates.

10. An ion mobility spectrometer, characterized in that, It includes the lateral migration-based ion mobility spectrometer as described in any one of claims 1 to 6, and a control unit and a signal processing unit for controlling the operation of the analyzer.

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