CN107941897B - Bipolar controllable pulse corona discharge ionization source and ion mobility spectrometer thereof - Google Patents
Bipolar controllable pulse corona discharge ionization source and ion mobility spectrometer thereof Download PDFInfo
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- 238000001514 detection method Methods 0.000 claims description 49
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- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 6
- 239000007789 gas Substances 0.000 description 6
- 230000005012 migration Effects 0.000 description 6
- 238000001871 ion mobility spectroscopy Methods 0.000 description 5
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 4
- OSWPMRLSEDHDFF-UHFFFAOYSA-N methyl salicylate Chemical compound COC(=O)C1=CC=CC=C1O OSWPMRLSEDHDFF-UHFFFAOYSA-N 0.000 description 4
- 230000002285 radioactive effect Effects 0.000 description 4
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- 229960001047 methyl salicylate Drugs 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
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- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
- G01N27/622—Ion mobility spectrometry
- G01N27/624—Differential mobility spectrometry [DMS]; Field asymmetric-waveform ion mobility spectrometry [FAIMS]
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
- G01N27/68—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode using electric discharge to ionise a gas
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
- H01J49/02—Details
- H01J49/022—Circuit arrangements, e.g. for generating deviation currents or voltages ; Components associated with high voltage supply
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
- H01J49/26—Mass spectrometers or separator tubes
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Abstract
The invention discloses a bipolar controllable pulse corona discharge ionization source and an ion mobility spectrometer thereof, comprising a pulse high-voltage module, an electrode base and an electrode arranged on the electrode base, wherein the electrode is electrically connected with the pulse high-voltage module, the electrode comprises a first electrode and a second electrode, the first electrode comprises a first electrode I and a first electrode II which are arranged in parallel, the first electrode I and the first electrode II are vertically arranged on the electrode base, and the first electrode I and the first electrode II are separated by an insulating partition board and are respectively used for generating positive ions and negative ions; the second electrode is a mesh of metal with mesh that covers the open end of the electrode base over the first electrode. The bipolar controllable high-voltage pulse corona discharge ionization source has the advantages of simple structure, capability of generating positive/negative ions simultaneously under the atmospheric pressure condition, high signal intensity, stable discharge performance, excellent ionization efficiency and long overall service life.
Description
Technical Field
The invention relates to the technical field of gas phase detection, in particular to a bipolar controllable pulse corona discharge ionization source and an ion mobility spectrometer thereof.
Background
Ion mobility spectrometry (Ion Mobility Spectrometry, IMS) is a new gas phase analytical detection technology developed over the last several decades, and is mainly used for characterizing various chemical substances by the mobility of gaseous ions, so as to achieve the purpose of analyzing and detecting various substances. The ion mobility spectrometer can work under the conditions of atmospheric pressure and room temperature, has simple structure, high analysis speed and high sensitivity, and is particularly suitable for trace detection of some volatile organic compounds. Ion mobility spectrometry has shown its unlimited potential in many fields such as national security, environmental monitoring, biomedical science, food sanitation, etc.
The sample to be tested enters the reaction zone through the air inlet under the drive of the carrier gas, and relatively stable product ions are generated through the processes of proton abstraction reaction, electron attachment reaction, electron exchange reaction and the like under the action of the ionization source. Product ions enter the drift region at the same time through the control of the ion gate. The drift region is a section of uniform electric field in the atmosphere, the electric field strength is about 200-400V/cm, and the product ions are accelerated by the electric field and decelerated by collision of reverse neutral atmospheric molecules, so that the product ions macroscopically obtain a constant average speed. Because the charge-to-mass ratio, the space geometry, the collision cross section and the like of different product ions are different, the obtained average speeds are also different, so that different product ions are successfully separated in an electric field and successively reach a Faraday receiving electrode, thereby obtaining an ion mobility spectrometry signal, and the type and the concentration of a sample to be detected can be obtained through data processing and database retrieval.
The ionization source is mainly used for ionizing sample molecules into ions under the atmospheric pressure condition so as to perform separation detection in a drift region. It is generally desirable that the ionization source be capable of sufficiently ionizing the sample while also being less susceptible to the effects of air constituents. The usual ionization methods are as follows: radiation ionization, corona discharge ionization, ultraviolet lamp ionization, laser ionization, electrospray ionization, flame ionization, surface ionization and the like. At present, the most commonly used ionization source is a metal foil made of radioactive materials, an external power supply is not needed, the application is simple, the ionization source has radioactivity, the damage to human bodies is possibly caused, strict operation rules are provided in the aspects of use, transportation, processing, treatment and the like, and the problems of narrow linear range, poor selectivity, radioactive pollution and the like of the radioactive ionization source are solved, so that the development of an IMS detection technology is greatly limited. Corona discharge is one of the main discharge modes for generating plasma under normal pressure, and compared with a radioactive ionization source, the electron density generated by the corona discharge is large, so that the detection sensitivity of the whole instrument can be improved, and a larger dynamic range can be obtained. The corona discharge ion mobility spectrometer can detect non-volatile alkane and aromatic compounds which cannot be detected or have low sensitivity by some radioactive ionization source ion mobility spectrometers, and can directly analyze liquid samples.
The corona discharge mainly comprises two modes of direct current corona discharge and pulse corona discharge. Most of early research work is mainly direct-current corona discharge, but the advantages of pulse corona discharge are obvious, so that the loss of a discharge needle electrode can be reduced, and the service life of the electrode is prolonged; nitrogen oxides NOX and O generated during corona discharge 3 Can interfere gas phase molecule-ion reaction, greatly reduce detection sensitivity of negative ion substances, and reduce NO by pulse corona discharge X And O 3 Is beneficial to eliminate the adverse effect on normal product ions.
The scheme of the cooperative detection of positive and negative ions of an ion mobility spectrometer is discussed in the Chinese patent document CN101339160B, and the polarity switching direct-current high-voltage corona discharge is adopted; the Chinese patent document CN102479659A adopts direct-current high-voltage corona discharge, and the Chinese patent document CN104752148A mainly adopts a plurality of corona needles capable of independently controlling high-voltage on-off; chinese patent document CN203983231 is a positive ion detection pulse corona discharge ion mobility spectrometer. However, the above patents have a common problem of lack of structure and practical application of the positive and negative ion pulse corona discharge ionization source; in addition, the related ion mobility spectrometers are all operated in a single ion polarity mode, so that the simultaneous detection of positive ions and negative ions of a sample to be detected cannot be realized, and the application of the instrument is limited. No ion mobility spectrometer can use a single detector and a positive and negative ion pulse corona discharge ionization source to realize real rapid collaborative detection of positive and negative ions, and the requirements of on-line detection of the instrument cannot be met.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides the bipolar controllable pulse corona discharge ionization source and the ion mobility spectrometer thereof, which have the advantages of simple design structure, capability of simultaneously generating positive/negative ions under the atmospheric pressure condition, stable discharge performance, excellent ionization efficiency and overall service life.
In order to achieve the above purpose, the invention adopts the following technical scheme:
in one aspect, the invention provides a bipolar controllable pulse corona discharge ionization source, which comprises a pulse high-voltage module, an electrode base and an electrode arranged on the electrode base, wherein the electrode is electrically connected with the pulse high-voltage module, the electrode comprises a first electrode and a second electrode, the first electrode comprises a first electrode I and a first electrode II which are arranged in parallel, the first electrode I and the first electrode II are vertically arranged on the electrode base, and the first electrode I and the first electrode II are separated by an insulating partition board and are respectively used for generating positive ions and negative ions; the second electrode is a mesh of metal with mesh that covers the open end of the electrode base over the first electrode.
The first electrode I and the first electrode II are needle-shaped electrodes.
The diameters of the first electrode I and the first electrode II are 0.1-0.3mm, and the lengths thereof are 3-5mm.
The electrode base is of a cylindrical structure with one end open, the mesh diameter and the mesh interval on the metal mesh are 0.4-0.6mm, and the thickness of the metal mesh is 0.15-0.25mm.
The electrode base is a ceramic base.
On the other hand, the invention also provides an ion mobility spectrometer, which comprises a central processing unit, a pulse discharge ionization source, a mobility tube and a signal detection device, wherein a reaction area, an ion gate, a drift area, a grid mesh and a Faraday disc are sequentially arranged along the axial direction of the mobility tube, the signal detection device is respectively and electrically connected with the central processing unit and the Faraday disc, the pulse discharge ionization source is arranged close to the reaction area of the mobility tube, the pulse discharge ionization source is the bipolar controllable pulse corona discharge ionization source, the central processing unit is electrically connected with the pulse high-voltage module and is used for generating positive high voltage at the positive high-voltage end of the pulse high-voltage module, generating negative high voltage at the negative high-voltage end of the pulse high-voltage module and being electrically connected with the second electrode and the ion gate through a resistor R2, and the central processing unit is respectively and electrically connected with the first electrode II.
The reaction zone and the drift zone are hollow pipes formed by alternately arranging a plurality of metal electrode rings and insulating ceramic rings.
The central processing unit controls the high-voltage pulse generated by the pulse high-voltage module to be generated before the ion gate pulse.
The high voltage pulses generated in one detection period of the signal detection device are 1-3, and the duration of each high voltage pulse is 0.5-3ms.
The central processing unit comprises a polarity switching module which is used for automatically switching the mode detection of positive and negative ions in the pulse high-voltage module, and the polarity switching module switches the mode detection of the positive and negative ions once every 1-2 s.
The technical scheme of the invention has the following advantages:
A. the bipolar controllable high-voltage pulse corona discharge ionization source has the advantages of simple structure, capability of generating positive/negative ions simultaneously under the atmospheric pressure condition, high signal intensity, stable discharge performance, excellent ionization efficiency and long overall service life.
B. The ion mobility spectrometer provided by the invention can realize automatic switching of positive and negative mode detection through the polarity switching module in the central processing unit, only one signal detection device is used for carrying out polarity switching of a high-voltage electric field every 1-2s, and positive/negative ion cooperative detection of a substance to be detected is realized by means of migration and separation of positive/negative ions in the electric field, so that the resolution can reach more than 25, the detection sensitivity is high, the application range of the ion mobility spectrometer is expanded, and the detection performance of the ion mobility spectrometer is improved.
C. Compared with the traditional ion mobility spectrometry using a radioactive source, the ion mobility spectrometer has no radioactivity, is convenient to use, maintain and manage, and has high resolution, high detection sensitivity and high detection accuracy. The method can realize the cooperative work of positive and negative mode detection, and is suitable for the rapid on-line detection and alarm of toxic and harmful gases.
Drawings
In order to more clearly illustrate the embodiments of the present invention, the drawings that are required for the embodiments will be briefly described, and it will be apparent that the drawings in the following description are some embodiments of the present invention and that other drawings may be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic perspective view of a bipolar controlled pulse corona discharge ionization source component;
FIG. 2 is a cross-sectional view of the structure of FIG. 1;
FIG. 3 is a top view of the structure of FIG. 1;
FIG. 4 is a schematic diagram of an ion mobility spectrometer with bipolar controllable pulse corona discharge ionization source components;
FIG. 5 is a schematic representation of the relationship of the instrument controllable high voltage pulse corona discharge pulse waveform to the ion gate pulse waveform of the present invention;
FIG. 6 is an ion mobility spectrum of positive/negative ion air reaction ion peaks of an ion mobility spectrometer of the present invention;
FIG. 7 is an ion mobility spectrum of an ion mobility spectrometer of the present invention detecting an acetone sample;
FIG. 8 is an ion mobility spectrum of a sample of methylene chloride detected by an ion mobility spectrometer of the present invention;
FIG. 9 is an ion mobility spectrum of the invention for detecting methyl salicylate samples with an ion mobility spectrometer.
Reference numerals illustrate:
1-a pulse high voltage module; 2-electrode base; 3-electrode, 31-first electrode, 311-first electrode I, 312-first electrode II, 32-second electrode; 4-insulating spacers; 5-a central processing unit; 6-migration tube, 61-reaction zone, 62-ion gate, 63-drift zone, 64-grid, 65-Faraday disk; 7-a signal detection device; 8-a pulsed discharge ionization source; 9-power supply system.
Detailed Description
The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
As shown in fig. 1, 2, 3 and 4, the present invention provides a bipolar controllable pulse corona discharge ionization source, which comprises a pulse high voltage module 1, an electrode base 2 and an electrode 3 mounted on the electrode base 2, wherein the electrode base 2 is preferably a ceramic base. The electrode 3 is electrically connected with the pulse high-voltage module 1, the electrode 3 comprises a first electrode 31 and a second electrode 32, the first electrode 31 comprises a first electrode I311 and a first electrode II312 which are arranged in parallel, the first electrode I311 and the first electrode II312 are vertically arranged on the electrode base 2, and the first electrode I311 and the first electrode II312 are separated by an insulating partition board 4 and are respectively used for generating positive ions and negative ions; the second electrode 32 is a mesh-like metal mesh sheet that covers the open end of the electrode base 2 above the first electrode 31.
The first electrode I311 and the first electrode II312 have needle shapes, are a pair of needle electrodes which are arranged in parallel, have the diameter of 0.1-0.3mm, the length of 3-5mm, the preferred diameter of 0.2mm and the length of 4mm, the interval between the two needles is about 8mm, and the needle electrode material is 99.95 percent platinum, and the needle electrodes can be used interchangeably; the second electrode has a circular shape, is a stainless steel special mesh, and has a diameter of preferably 25mm, a mesh diameter and a spacing of preferably 0.5mm, and a thickness of preferably 0.2mm, and is fixed on the top end of the ceramic base. The pulse high-voltage module is arranged on a PCB and is used for providing pulse high voltage for the whole system.
As shown in fig. 4, the present invention further provides an ion mobility spectrometer, including a central processing unit 5, a pulse discharge ionization source 8, a mobility tube 6, a signal detection device 7 and a power supply system 9, where the power supply system 9 is used to supply power to the central processing unit and the pulse discharge ionization source 8, a reaction area 61, an ion gate 62, a drift area 63, a grid 64 and a faraday disk 65 are sequentially disposed along an axial direction of the mobility tube 6, the signal detection device 7 is electrically connected with the central processing unit 5 and the faraday disk 65, the pulse discharge ionization source is disposed near the reaction area 61 of the mobility tube 6, the pulse discharge ionization source is a bipolar controllable pulse corona discharge ionization source 8, the central processing unit 5 is electrically connected with the pulse high voltage module 1, and is used to generate a positive high voltage at a positive high voltage end of the pulse high voltage module 1, and is loaded onto the first electrode I311 through a resistor R1, a negative high voltage is generated at a negative high voltage end of the pulse high voltage module 1, and is loaded onto the first electrode II312 through a resistor R2, and the central processing unit 5 is electrically connected with the second electrode 32 and the ion gate 62, respectively. The reaction zone 61 and the drift zone 63 are hollow tubes formed by alternately arranging a plurality of metal electrode rings and insulating ceramic rings, direct-current high voltage is applied to two ends of the hollow tubes, and the metal electrode rings are divided by resistors so as to obtain a uniform axial electric field.
The on-off of the pulse high-voltage module (i.e. bipolar controllable pulse corona discharge) and the ion gate pulse keep a certain time sequence, as shown in fig. 5, the controllable high-voltage pulse corona discharge is generated before the ion gate pulse, the controllable high-voltage pulse is 1-3 in one detection period, and the duration of each high-voltage pulse is 0.5-3ms. The number of high voltage pulses in a detection period, the pulse duration length, is related to the number of ions generated. The controllable high-voltage pulse corona discharge can further reduce the loss of the electrode of the discharge needle, improve the service life of the discharge needle and possibly reduce NO X And O 3 The generation of ions is beneficial to eliminate the adverse effect of the ions on normal product ions.
When in actual use, the ion mobility spectrometer is connected with the upper computer through a data line, and the working state of the current ion mobility spectrometer can be monitored in real time by adopting independently developed upper computer software. In the non-sample state, the software displays positive/negative air ion peaks at the current moment, as shown in fig. 6. Fig. 6 is an ion mobility spectrum of positive/negative ion air reaction ion peaks of the ion mobility spectrometer of the present invention, calculated that the reduced mobility of the positive ion characteristic peak is 2.08, the peak height 618.4, and the reduced mobility of the negative ion characteristic peak is 2.30, and the peak height 501.1.
When the sample is detected, the software can display positive/negative characteristic ion peaks of the sample to be detected in real time, as shown in fig. 7-9, and further compare the positive/negative characteristic ion peaks with a database stored in an instrument, judge the type of the sample to be detected, display the type of the sample to be detected, and send an alarm if the concentration of the sample to be detected exceeds an alarm limit value.
The central processing unit generates pulse to act on 4 feet of the controllable pulse high-voltage module, then 1 foot (+end) of the module generates positive high voltage, the positive high voltage is loaded on the first electrode I through the resistor R1, at the moment, the potential on the electrode is +HV1, potential difference is formed between the positive high voltage and the potential HV3+ on the second electrode, +HV1 is higher than HV3 plus about 3000V, an uneven electrostatic field is formed in a space between the first electrode I and the second electrode, gas ionization is further generated under the atmospheric pressure condition, HV3+ is simultaneously loaded on a first electrode ring of a reaction area, positive ions generated by an ionization source can axially pass through an ion gate under the action of the electric field force, and different positive ion average speeds are different, so that the positive ions are successfully separated in the electric field and reach a Faraday plate in sequence, and positive ion migration spectrum signals of substances to be detected are obtained.
FIG. 7 is an ion mobility spectrum of an acetone sample detected by the ion mobility spectrometer of the present invention, and as can be seen from FIG. 7, there is almost no change in the negative ion peak compared with the air reaction ion peak, and a new characteristic peak is generated by positive ions, and the calculated reduced mobility of the characteristic peak is 1.80 and the peak height is 298.9.
The central processing unit generates pulse to act on 5 feet of the controllable pulse high-voltage module, then the 2 feet (-end) of the module generate negative high voltage, the negative high voltage is loaded on the first electrode II through the resistor R2, the potential on the electrode is-HV 2 at the moment and the potential on the second electrode HV 3-forms potential difference, -HV2 is lower than HV3 to about 3000V, a nonuniform electrostatic field is formed in the space between the first electrode II and the second electrode, then gas ionization is generated under the atmospheric pressure condition, HV 3-is loaded on the first electrode ring of the reaction zone at the same time, negative ions generated by the ionization source can pass through the ion gate along the axial direction under the action of the electric field force, and different negative ion average speeds are different, so that the negative ions are successfully separated in the electric field and sequentially reach the Faraday disk, and negative ion migration spectrum signals of substances to be detected are obtained. FIG. 8 is an ion mobility spectrum of a sample of methylene chloride detected by an ion mobility spectrometer of the present invention, and as can be seen from FIG. 8, there is hardly any change in the positive ion peak compared to the air reaction ion peak; the negative ions produced a new characteristic peak, which was calculated to have a reduced mobility of 2.65 and a peak height of 290.2.
The central processing unit is used for coordinating each module of the ion mobility spectrometer to complete the detection function, so that effective detection data are finally obtained and the result is presented to a user. The ARM chip, the FPGA chip and the peripheral circuit in the central processing unit jointly perform high-voltage switching on the pulse high-voltage module, and closed-loop feedback control on the ion gate and signal detection is a key for realizing positive/negative ion collaborative detection by the ion mobility spectrometer. When positive ion mode detection is carried out, the potential of the first electrode I is controlled to be +HV1 by pulse, meanwhile, the potential of the second electrode is switched to be kept at HV3+, an ion gate is opened later, and after a Faraday disc receives a signal, a positive ion migration spectrogram is obtained through a signal detection device and AD conversion; when negative ion mode detection is carried out, the potential of the first electrode II is controlled to be-HV 2 through pulses, meanwhile, the potential of the second electrode is switched to be kept at HV3-, an ion gate is opened later, and after a Faraday disc receives signals, a negative ion migration spectrogram is obtained through a signal detection device and AD conversion; the central processing unit preferably switches positive and negative ion modes every 1.5s, and realizes the cooperative detection of positive and negative ions of a substance to be detected by means of migration and separation of positive and negative ions in an electric field, the resolution can reach more than 25, the detection sensitivity is high, the application range of the ion mobility spectrometer is expanded, and the detection performance of the ion mobility spectrometer is improved. FIG. 9 is an ion mobility spectrum of a sample of methyl salicylate detected by an ion mobility spectrometer according to the present invention, and as can be seen from FIG. 9, each of positive and negative ions generates a new characteristic peak compared with the air reaction ion peak, and the calculated reduced mobility of the positive ion characteristic peak is 1.62 and the peak height is 237.2; the reduced mobility of the characteristic peak of the negative ion is 1.47, and the peak height is 108.5.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While obvious variations or modifications are contemplated as falling within the scope of the present invention.
Claims (10)
1. The bipolar controllable pulse corona discharge ionization source comprises a pulse high-voltage module (1), an electrode base (2) and an electrode (3) arranged on the electrode base (2), wherein the electrode (3) is electrically connected with the pulse high-voltage module (1), the bipolar controllable pulse corona discharge ionization source is characterized in that the electrode (3) comprises a first electrode (31) and a second electrode (32), the first electrode (31) comprises a first electrode I (311) and a first electrode II (312) which are arranged in parallel, the first electrode I (311) and the first electrode II (312) are vertically arranged on the electrode base (2), and the first electrode I (311) and the first electrode II (312) are separated through an insulating partition board (4) and are respectively used for generating positive ions and negative ions; the second electrode (32) is a metal mesh with meshes, which covers the open end of the electrode base (2) above the first electrode (31).
2. The bipolar controlled pulsed corona discharge ionization source of claim 1, wherein the first electrode I (311) and the first electrode II (312) are both needle electrodes.
3. The bipolar controlled pulsed corona discharge ionization source of claim 2, wherein the first electrode I (311) and the first electrode II (312) have a diameter of 0.1-0.3mm and a length of 3-5mm.
4. The bipolar controllable pulse corona discharge ionization source according to claim 1, wherein the electrode base (2) has a cylindrical structure with one end opened, the mesh diameter and the mesh interval on the metal mesh are 0.4-0.6mm, and the thickness of the metal mesh is 0.15-0.25mm.
5. The bipolar controlled pulsed corona discharge ionization source of claim 4, wherein said electrode base (2) is a ceramic base.
6. An ion mobility spectrometer comprises a central processing unit (5), a pulse discharge ionization source, a mobility tube (6) and a signal detection device (7), wherein a reaction area (61), an ion gate (62), a drift area (63), a grid (64) and a Faraday disc (65) are sequentially arranged along the axial direction of the mobility tube (6), the signal detection device (7) is respectively and electrically connected with the central processing unit (5) and the Faraday disc (65), the pulse discharge ionization source is close to the reaction area (61) of the mobility tube (6), and the ion mobility spectrometer is characterized in that the pulse discharge ionization source is a bipolar controllable pulse corona discharge ionization source according to any one of claims 1-5, the central processing unit (5) is electrically connected with a pulse high-voltage module (1) and is used for generating positive high voltage at a positive high voltage end of the pulse high-voltage module (1), and is loaded onto a first electrode I (311) through a resistor R1, generating negative high voltage at a negative high voltage end of the pulse high-voltage module (1), and is electrically connected with a second electrode (312) through the resistor R2 and a second electrode (32) respectively.
7. The ion mobility spectrometer according to claim 6, wherein the reaction zone (61) and the drift zone (63) are hollow tubes composed of a plurality of metal electrode rings and insulating ceramic rings alternately arranged, respectively.
8. The ion mobility spectrometer according to claim 6, characterized in that said central processing unit (5) controls the generation of high voltage pulses generated by said pulsed high voltage module (1) before the pulses of said ion gate (62).
9. Ion mobility spectrometer according to claim 6, characterized in that the number of high voltage pulses generated in one detection cycle of the signal detection means (7) is 1-3, each high voltage pulse having a duration of 0.5-3ms.
10. The ion mobility spectrometer of claim 6, wherein the central processing unit includes a polarity switching module for automatically switching the mode detection of positive and negative ions in the pulsed high voltage module, and the polarity switching module switches the positive and negative ion mode detection every 1-2 s.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201711244956.6A CN107941897B (en) | 2017-11-30 | 2017-11-30 | Bipolar controllable pulse corona discharge ionization source and ion mobility spectrometer thereof |
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| CN108899264B (en) * | 2018-06-07 | 2020-01-31 | 中国科学院合肥物质科学研究院 | high-sensitivity high-field asymmetric waveform ion mobility spectrometry detection device |
| CN111220696B (en) * | 2018-11-25 | 2021-11-09 | 中国科学院大连化学物理研究所 | Ion trap mass spectrometer with fast switching of positive and negative ion detection modes and detection method thereof |
| CN111077212A (en) * | 2019-12-17 | 2020-04-28 | 北京声迅电子股份有限公司 | Ion sensor based on FAIMS principle |
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