CN108091537B - Step field ion migration tube - Google Patents
Step field ion migration tube Download PDFInfo
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- CN108091537B CN108091537B CN201611040326.2A CN201611040326A CN108091537B CN 108091537 B CN108091537 B CN 108091537B CN 201611040326 A CN201611040326 A CN 201611040326A CN 108091537 B CN108091537 B CN 108091537B
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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
- H01J49/34—Dynamic spectrometers
- H01J49/40—Time-of-flight spectrometers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
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Abstract
The invention relates to an ion migration tube in an ion mobility spectrometry instrument, in particular to an ion migration tube with an internal electric field of an ion migration area weakened in a step shape. The ion migration region electric field is characterized by being composed of direct current electric fields which are identical in direction and weakened in sequence according to the same difference value. The DC electric field forming mode can fully utilize the space-time focusing effect of electric field difference on ion clusters, and improve the sensitivity and resolution of ion mobility spectrometry.
Description
Technical Field
The invention relates to an ion migration tube in an ion mobility spectrometry instrument, in particular to an ion migration tube with an internal electric field in an ion migration area gradually reduced in a step shape. The ion migration region electric field is characterized by being composed of direct current electric fields which are identical in direction and weakened in sequence according to the same difference value. The DC electric field forming mode can fully utilize the space-time focusing effect of electric field difference on ion clusters, and improve the sensitivity and resolution of ion mobility spectrometry.
Background
Ion Mobility Spectrometry (IMS) resolution (Resolving Power, R) is one of the most interesting technical indicators in Ion Mobility Spectrometry. In general, R is defined as the migration time (t) of the ion peakd) And full width at half maximum (w) of ion peak0.5) Ratio of (i) to (ii)
According to w0.5R can be further expressed as
As can be seen from equation 2, the door opening time t is determined by the fixed ionsgWhen t isdIs an important factor affecting the fraction. Within a certain range, t is reduceddThe R of the IMS can be increased.
According to equation 3, for ions with a particular mobility K, t is reduceddThe most effective way is to increase the electric field strength E inside the ion transport tube.
In addition, Du et al (anal. chem.,2012,84,1725) proposed a Compression-diffusion Model (Compression-Dispersion Model for Ambient ion transport) in 2012 to explain the effect of changes in electric field on the time and space dimensions of ion packets. The model indicates that if the ion packets move along a dc electric field with decreasing electric field strength, the ion packets are compressed in both spatial and temporal widths.
The above cognition provides a new idea for improving the sensitivity and the separation capability of the ion mobility spectrometry: constructing a direct current electric field with the same direction and gradually reduced intensity in a migration region of the ion migration tube, and reducing the migration time t of ion clustersdMeanwhile, the sensitivity and the resolution capability of the ion migration tube are improved by fully utilizing the space-time compression effect of the electric field gradient change on the ion clusters.
The invention content is as follows:
the invention aims to improve the resolution capability and sensitivity of an ion mobility spectrum to different ions by constructing a direct current electric field with gradient decreasing in an ion migration region and utilizing the space compression effect of a non-uniform electric field to ion clusters.
In order to achieve the purpose, the invention adopts the technical scheme that:
an electric field in an ion migration region is composed of direct current electric fields which are identical in direction and are weakened sequentially according to the same difference, and a cylindrical ion migration region of which the electric field is a stepped electric field is formed in the ion migration tube.
The ion migration tube is internally provided with a hollow cylinder structure formed by sequentially and coaxially overlapping more than M annular conductive pole pieces and more than M-1 annular insulating pole pieces in an alternating and overlapping manner, the hollow part in the cylinder is a columnar ion migration area, and the ion migration area is positioned between the ion source and the ion receiving pole; m is a positive integer greater than or equal to 4;
the electric field in the ion migration zone is formed by direct current electric fields which have the same direction and are sequentially weakened by the same difference value, and the direct current electric fields refer to that: along the direction from an ionization source to an ion receiving electrode, applying a first direct current electric field between the first conducting pole piece and the second conducting pole piece, applying a second direct current electric field between the second conducting pole piece and the third conducting pole piece, applying a third direct current electric field between the third conducting pole piece and the fourth conducting pole piece, and applying an M-1 direct current electric field between the M-1 conducting pole piece and the M conducting pole piece at … …;
the difference value of the first direct current electric field and the second direct current electric field is equal to the difference value of the second direct current electric field and the third direct current electric field, and … … is equal to the difference value of the M-2 direct current electric field and the M-1 direct current electric field;
the directions of the first, second and third DC electric fields … … are the same as the M-1 DC electric field.
The direct current electric field satisfies the condition that E/N is more than 0 and less than or equal to 4Td, wherein E represents the electric field intensity, N represents the number density of gas molecules, and the difference is between 0.01 and 1 Td.
Along the axial direction of the ion migration zone, an ion gate is arranged on one side of the ion migration zone, and an ion receiving electrode and an air inlet are arranged on the other side of the ion migration zone; an ion source with a gas inlet and a gas outlet is disposed on a side of the ion gate remote from the ion transfer region.
The ion gate is any one of Bradbury-Neilson type and Tyndall-Powell type;
the ion source is any ion source capable of ionizing sample molecules under the atmospheric pressure condition.
Gas carrying a sample to be detected enters the ion source through a gas inlet arranged on the ion source, and sample molecules are ionized into sample ions in the ion source;
sample ions enter an ion migration area through an ion gate which is opened periodically, sequentially arrive at an ion detection electrode under the drive of a non-uniform direct current electric field, and are converted into spectrogram information of current intensity to time to be output;
when the process is carried out, the other path of gas enters the ion migration area from the gas inlet arranged on the ion migration area, flows out of the ion migration area along the direction opposite to the flight direction of the ions, and finally flows out of the ion migration pipe from the gas outlet arranged on the ion source together with the gas carrying the sample to be detected.
The gas is O2、N2、CO2、H2And Ar, or a mixture of two or more gases.
The invention has the advantages that:
the invention fully utilizes the space compression effect of the non-uniform electric field on the ion cluster to improve the resolution capability and the sensitivity of the ion mobility spectrometry on different ions.
The invention is described in further detail below with reference to the accompanying drawings:
description of the drawings:
FIG. 1 shows a stepped electric field ion mobility tube. Wherein: 1-ionization region; 2-ion gate; 3-migration zone; 4-a Faraday disk; 5-floating gas inlet; 6-sample gas inlet; 7-air outlet; 8-ionization source.
Fig. 2 shows signal spectra of 50ppb of acetone in a conventional constant-uniform field ion mobility tube and a stepped-field ion mobility tube, respectively.
The specific implementation mode is as follows:
example 1
The present invention utilizes a hollow ring-shaped electrode and a hollow ring-shaped insulator to construct a cylindrical ion transport region, as shown in fig. 1. The length of the entire ion transfer region 3 was kept at 7.2 cm. The electric field in the ion migration zone is composed of direct current electric fields which have the same direction and are weakened according to the same difference value in sequence, and a cylindrical ion migration zone with a stepped electric field is formed in the ion migration zone.
The ion migration tube is internally provided with a hollow cylinder structure which is formed by sequentially and coaxially overlapping ten annular conductive pole pieces with the thickness of 1mm and the inner diameter of 22mm and nine annular insulating pole pieces with the thickness of 7mm and the inner diameter of 22mm, wherein the hollow part in the cylinder is a columnar ion migration area 3 which is positioned between an ion source 8 and an ion receiving pole 4;
the electric field inside the ion transfer region 3 is composed of nine direct current electric fields which have the same direction and are sequentially weakened by the same difference. Along the direction from the ionization source to the ion receiving electrode, a first direct current electric field is applied between the first conducting pole piece and the second conducting pole piece, a second direct current electric field is applied between the second conducting pole piece and the third conducting pole piece, a third direct current electric field is applied between the third conducting pole piece and the fourth conducting pole piece, … … a ninth direct current electric field is applied between the ninth conducting pole piece and the tenth conducting pole piece,
the difference value between the first direct current electric field and the second direct current electric field is equal to the difference value between the second direct current electric field and the third direct current electric field, and … … is equal to the difference value between the eighth direct current electric field and the ninth direct current electric field; the difference was kept at 50-150V/cm.
The first, second, and third dc fields … … and … … are in the same direction.
Along the axial direction of the ion migration zone 3, an ion gate 2 is arranged on one side of the ion migration zone 3, and an ion receiving electrode 4 and an air inlet 5 are arranged on the other side; an ion source 8 with a gas inlet 6 and a gas outlet 7 is disposed on the side of the ion gate 2 remote from the ion transfer region 3.
The ion gate may be of the Bradbury-Neilson type; the ion source 8 is63A Ni ionization source.
Gas carrying a sample to be detected enters an ion source through a gas inlet 6 arranged on the ion source 8, and sample molecules are ionized into sample ions in the ion source;
sample ions enter an ion migration region 3 through an ion gate 2 which is opened periodically, are compressed and focused in other spaces under the drive of a stepped electric field, sequentially reach an ion detection electrode 4 and are converted into spectrogram information of current intensity to time and output;
while the process is carried out, the drift gas enters the ion migration area 3 from the gas inlet 5 arranged on the ion migration area 3, flows out of the ion migration area 3 along the direction opposite to the flight direction of the ions, and finally flows out of the ion migration tube from the gas outlet 7 arranged on the ion source 8 together with the gas carrying the sample to be detected.
The gas is clean air filtered by molecular sieve and active carbon.
Comparative application
A step field ion mobility tube. The length of the migration zone is 7.2 cm; the migration area has 9 electric fields which are gradually decreased according to the step with the electric field intensity difference of 50V/cm, wherein the intensity of the last electric field is 338V/cm, and the electric field intensity of the ionization area is 738V/cm; the temperature of the ion transfer tube is 100 ℃; the air flow rate of the sample is 5mL/min, and the air flow rate of the floating air is 100 mL/min; the ion source being 15mCi (milliCurie)63A source of Ni; the ion gate uses a Bradbury Nielsen type ion gate with a wire spacing of 1mm, the ion gate closing voltage is 1500V/cm, and the ion gate opening time interval is 50 mus; in FIG. 2, an ion signal peak was observed at a signal intensity of 750pA and a resolution of 50 for 50ppb of acetone.
To compare the advantages of the above-described step-field ion mobility tube, the signal of 50ppb of acetone in a conventional constant-uniform-field ion mobility tube was also obtained. The conditions were as follows: the length of the migration zone is 7.2 cm; the electric field intensity in the migration area is constant at 338V/cm, and the electric field intensity in the ionization area is constant at 338V/cm; the temperature of the ion transfer tube is 100 ℃; the air flow rate of the sample is 5mL/min, and the air flow rate of the floating air is 100 mL/min; the ion source being 15mCi (milliCurie)63A source of Ni; the ion gate uses a BradbryNielsen type ion gate with a wire spacing of 1mm, the opening time interval of the ion gate is 50 mus, and the closing voltage of the ion gate is 1500V/cm; the ion signal peak formed by 50ppb of acetone is also shown in FIG. 2, with a signal intensity of 180pA and a resolution of 25. Comparing the two spectra, the ion peak with stronger signal intensity and higher resolution ratio formed by 50ppb acetone in the step field ion migration tube can be seen.
Claims (6)
1. A step-field ion mobility tube, comprising:
the electric field in the ion migration area is composed of direct current electric fields which have the same direction and are weakened according to the same difference value in sequence, and a cylindrical ion migration area with a stepped electric field is formed in the ion migration area;
the ion migration tube is internally provided with a hollow cylinder structure formed by sequentially and coaxially overlapping more than M annular conductive pole pieces and more than M-1 annular insulating pole pieces in an alternating and overlapping manner, the hollow part in the cylinder is a columnar ion migration area, and the ion migration area is positioned between the ion source and the ion receiving pole; m is a positive integer greater than or equal to 4;
the electric field in the ion migration zone is formed by direct current electric fields which have the same direction and are sequentially weakened by the same difference value, and the direct current electric fields refer to that: along the direction from an ionization source to an ion receiving electrode, applying a first direct current electric field between the first conducting pole piece and the second conducting pole piece, applying a second direct current electric field between the second conducting pole piece and the third conducting pole piece, applying a third direct current electric field between the third conducting pole piece and the fourth conducting pole piece, and applying an M-1 direct current electric field between the M-1 conducting pole piece and the M conducting pole piece at … …;
the difference value of the first direct current electric field and the second direct current electric field is equal to the difference value of the second direct current electric field and the third direct current electric field, and … … is equal to the difference value of the M-2 direct current electric field and the M-1 direct current electric field;
the directions of the first, second and third DC electric fields … … are the same as the M-1 DC electric field.
2. The ion transfer tube of claim 1, wherein: the direct current electric field satisfies the condition that E/N is more than 0 and less than or equal to 4Td, wherein E represents the electric field intensity, N represents the number density of gas molecules, and the difference is between 0.01 and 1 Td.
3. The ion transfer tube of claim 1, wherein: along the axial direction of the ion migration zone, an ion gate is arranged on one side of the ion migration zone, and an ion receiving electrode and an air inlet are arranged on the other side of the ion migration zone; an ion source with a gas inlet and a gas outlet is disposed on a side of the ion gate remote from the ion transfer region.
4. The ion transfer tube of claim 3, wherein: the ion gate is any one of Bradbury-Neilson type and Tyndall-Powell type;
the ion source is any ion source capable of ionizing sample molecules under the atmospheric pressure condition.
5. An ion transfer tube according to any of claims 1 to 4, wherein: gas carrying a sample to be detected enters the ion source through a gas inlet arranged on the ion source, and sample molecules are ionized into sample ions in the ion source;
sample ions enter an ion migration area through an ion gate which is opened periodically, sequentially arrive at an ion detection electrode under the drive of a non-uniform direct current electric field, and are converted into spectrogram information of current intensity to time to be output;
when the process is carried out, the other path of gas enters the ion migration area from the gas inlet arranged on the ion migration area, flows out of the ion migration area along the direction opposite to the flight direction of the ions, and finally flows out of the ion migration pipe from the gas outlet arranged on the ion source together with the gas carrying the sample to be detected.
6. The ion transfer tube of claim 5, wherein: the gas is O2、N2、CO2、H2And Ar, or a mixture of two or more gases.
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| CN201611040326.2A CN108091537B (en) | 2016-11-21 | 2016-11-21 | Step field ion migration tube |
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| CN201611040326.2A CN108091537B (en) | 2016-11-21 | 2016-11-21 | Step field ion migration tube |
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| CN108091537B true CN108091537B (en) | 2020-04-07 |
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| CN110487885B (en) * | 2018-11-25 | 2021-06-01 | 中国科学院大连化学物理研究所 | Device and method for high-flux measurement of ammonia in atmosphere |
| CN110491766A (en) * | 2018-11-25 | 2019-11-22 | 中国科学院大连化学物理研究所 | A kind of direct current inhomogeneous field transference tube |
| CN110487884B (en) * | 2018-11-25 | 2022-01-04 | 中国科学院大连化学物理研究所 | Use method of ion migration tube for complex sample separation and analysis |
| CN110828281B (en) * | 2019-11-15 | 2020-10-09 | 中国科学院大连化学物理研究所 | Ion enrichment ion migration tube |
| CN112490109B (en) * | 2020-11-24 | 2024-04-16 | 中国科学院大连化学物理研究所 | Time domain enhanced ion migration tube |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102954995A (en) * | 2011-08-19 | 2013-03-06 | 中国科学院大连化学物理研究所 | Non-uniform electric field based ion mobility spectrometer |
| CN105632874A (en) * | 2014-11-07 | 2016-06-01 | 中国科学院大连化学物理研究所 | DC non-uniform electric field ion migration tube |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7164122B2 (en) * | 2000-02-29 | 2007-01-16 | Ionwerks, Inc. | Ion mobility spectrometer |
| JP2007524964A (en) * | 2003-06-20 | 2007-08-30 | ブリガム・ヤング・ユニバーシティ | Single instrument for ion mobility analysis and ion trap mass spectrometry |
| CN2886569Y (en) * | 2005-05-30 | 2007-04-04 | 张秀庭 | Portable ion migration mass spectrograph for detecting explosive and drug |
| US7675031B2 (en) * | 2008-05-29 | 2010-03-09 | Thermo Finnigan Llc | Auxiliary drag field electrodes |
| CN102221576B (en) * | 2010-04-15 | 2015-09-16 | 岛津分析技术研发（上海）有限公司 | The method and apparatus of a kind of generation, analysis ion |
| US8581177B2 (en) * | 2011-04-11 | 2013-11-12 | Thermo Finnigan Llc | High duty cycle ion storage/ion mobility separation mass spectrometer |
| CN102856153A (en) * | 2012-10-08 | 2013-01-02 | 复旦大学 | Ion optical off-axis transmission system |
| CN103871820B (en) * | 2012-12-10 | 2017-05-17 | 株式会社岛津制作所 | Ion mobility analyzer and combination unit thereof and ion mobility analysis method |
| CN104282525A (en) * | 2013-07-01 | 2015-01-14 | 中国科学院大连化学物理研究所 | Ion focusing transmission lens under atmosphere pressure |
| CN104538278B (en) * | 2014-12-16 | 2017-01-04 | 中国科学院长春光学精密机械与物理研究所 | A kind of ion migration generating means and control method thereof |
| US9683964B2 (en) * | 2015-02-05 | 2017-06-20 | Bruker Daltonik Gmbh | Trapping ion mobility spectrometer with parallel accumulation |
| CN105428201A (en) * | 2015-12-25 | 2016-03-23 | 复旦大学 | Stepped electrode ion trap mass analyzer |
-
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- 2016-11-21 CN CN201611040326.2A patent/CN108091537B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102954995A (en) * | 2011-08-19 | 2013-03-06 | 中国科学院大连化学物理研究所 | Non-uniform electric field based ion mobility spectrometer |
| CN105632874A (en) * | 2014-11-07 | 2016-06-01 | 中国科学院大连化学物理研究所 | DC non-uniform electric field ion migration tube |
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