CN111243935A

CN111243935A - Ion mobility spectrometer of dielectric barrier discharge ionization source

Info

Publication number: CN111243935A
Application number: CN202010113230.4A
Authority: CN
Inventors: 张信华; 徐康; 黄炜; 李柏锦; 曹文彬
Original assignee: Changzhou Institute of Technology
Current assignee: Changzhou Institute of Technology
Priority date: 2020-02-24
Filing date: 2020-02-24
Publication date: 2020-06-05

Abstract

The invention relates to an ion mobility spectrometer, in particular to an ion mobility spectrometer of a dielectric barrier discharge ionization source, which has the advantages of reasonable structure, high detection sensitivity, stability and selectivity by taking dielectric barrier discharge as an ionization source device, and comprises an ionization source, a drift tube and a signal acquisition end, wherein the ionization source comprises a cylindrical shell, a glass tube, a radio frequency electrode, a lead, a radio frequency power supply and an accelerating electrode, the drift tube comprises a metal conducting ring and an insulating ring, the metal conducting ring and the insulating ring are alternately connected, the ionization source comprises a cylindrical shell, a radio frequency power supply, an accelerating electrode, a radio frequency electrode, a quartz glass tube and an accelerating electrode, the accelerating electrode is hermetically arranged at the front end of the cylindrical shell, the quartz glass tube is inserted into the cylindrical shell, the two radio frequency electrodes are inserted into the cylindrical shell and are sleeved on the outer wall of the quartz glass tube, the radio-frequency electrode is also connected with a radio-frequency power supply through a lead.

Description

Ion mobility spectrometer of dielectric barrier discharge ionization source

Technical Field

The invention relates to an ion mobility spectrometer, in particular to an ion mobility spectrometer of a dielectric barrier discharge ionization source.

Background

Ion Mobility Spectrometry (IMS) was developed in the 70 th 20 th century as a detection technology, and the separation principle thereof is to characterize various chemical substances by the Mobility of gaseous ions so as to analyze and detect various substances. The ion mobility spectrometer has the advantages of high detection sensitivity, quick measurement response, small instrument volume, low manufacturing cost and the like, and is widely applied to detection of volatile organic pollutants in chemical toxicants, drugs, dangerous goods and atmospheric environment at present.

The conventional ion mobility spectrometer mainly comprises a sampling device, an ionization source, a drift tube, an electric control part, a gas path circulating system, a signal acquisition and data processing system and the like. The drift tube mainly comprises an ion reaction region, an ion gate and a drift region. Ionization sources are an important component of ion mobility spectrometry. The most commonly used ionization sources of the existing ion mobility spectrometer are mainly a Ni63 ionization source, a corona discharge ionization source, a photoionization (including VUV lamp and laser) ionization source, an electrospray ionization source and the like.

The ionization source based on Ni63 has the advantages of high ionization rate, good stability and high detection sensitivity, but the application of the ion mobility spectrometer is greatly limited due to the radioactivity of Ni 63; corona discharge and photoionization ionization sources are suitable for ionizing gas-phase samples, and the types of ionized samples have certain limits; the electrospray ionization source is suitable for analyzing liquid samples, but the samples need to be subjected to complex pretreatment, and the device structure of the ionization source is also complex and is not suitable for field detection. Therefore, how to design an ion mobility spectrometer with high detection sensitivity and stable detection is a technical problem to be solved.

Disclosure of Invention

The invention aims to overcome the technical problems in the prior art, and provides an ion mobility spectrometer of a dielectric barrier discharge ionization source, which has the advantages of reasonable structure, high detection sensitivity, stability and selectivity by taking dielectric barrier discharge as an ionization source device.

In order to solve the technical problems, the invention provides the following technical scheme: an ion mobility spectrometer of a dielectric barrier discharge ionization source comprises an ionization source, a drift tube and a signal acquisition end, the ionization source comprises a cylindrical shell, a glass tube, a radio-frequency electrode, a lead, a radio-frequency power supply and an accelerating electrode, the drift tube comprises metal conductive rings and insulating rings, the metal conductive rings and the insulating rings are alternately connected, the ionization source comprises a cylindrical shell, a radio frequency power supply, an accelerating electrode, a radio frequency electrode, a quartz glass tube and an accelerating electrode, the accelerating electrode is hermetically arranged at the front end of the cylindrical shell, the quartz glass tube extends into the cylindrical shell, the two radio frequency electrodes are extended into the cylindrical shell and sleeved on the outer wall of the quartz glass tube, the radio frequency electrodes are also connected with a radio frequency power supply through leads, the quartz glass tube contains working gas and also comprises a sampling mechanism, and the sampling mechanism is arranged in the cylindrical shell.

Preferably, the front end of the drift tube is provided with an exhaust port, the tail end of the drift tube is provided with a drift gas inlet, and the tail end of the drift tube is also provided with a signal acquisition end.

Preferably, the sampling mechanism is a sampling tube.

Preferably, the sampling mechanism is a sample sampling table.

Preferably, the distance between the two radio frequency electrodes is 2-3 cm, and the distance between the radio frequency electrode at the lower part and the bottom end of the quartz glass tube is less than 5 mm.

Preferably, the glass tube is a quartz glass tube or a ceramic tube.

Preferably, the inner diameter of the glass tube is 1-2 mm, and the wall thickness is 0.5-2 mm. .

The invention has the beneficial effects that: the ion mobility spectrometer of the dielectric barrier discharge ionization source is used as an ionization source, the dielectric barrier discharge ionization source has the advantages of small volume, low electric energy consumption, stable discharge and the like, and a gas sample can be ionized at normal temperature and normal pressure to generate a large amount of stable and high-energy ions. Not only can the radioactive ionization source be avoided, but also the gas, liquid or solid sample can be directly ionized. Meanwhile, the sensitivity, stability and selectivity of the ion mobility spectrometry technology can be further improved, and the application field of the ion mobility spectrometry is widened.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.

Fig. 1 is a schematic structural diagram of an ion mobility spectrometer of a dielectric barrier discharge ionization source of the present invention.

Fig. 2 is another structural schematic diagram of the ion mobility spectrometer of the dielectric barrier discharge ionization source of the present invention.

Reference numbers in the figures: 1. a wire; 2. a radio frequency power supply; 3. a glass tube; 4. a radio frequency electrode; 5. a cylindrical housing; 6. an exhaust port; 7. an insulating ring; 8. conducting rings; 9. an ion gate; 10. a drift gas inlet; 11. a signal acquisition end; 12. an accelerating electrode; 13. a sampling mechanism; 14. an ion reaction zone; 15. a drift region; 16. a drift tube.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

In the implementation of the ion mobility spectrometer of the dielectric barrier discharge ionization source shown in fig. 1 and 2, the drift tube 16 is a hollow cavity tube formed by alternately arranging a plurality of metal conductive rings 8 and insulating rings 7, and comprises an ion reaction region 14, an ion gate 9 and a drift region 15. The sampling device is arranged in an ionization source, the ionization source is tightly connected with the front end of the drift tube, and the rear end of the drift tube is connected with the signal acquisition end 11; the carrier gas and the drift gas form gas path circulation in the drift tube; the invention relates to an ion mobility spectrometer, in particular to a drift tube, carrier gas and drift gas path circulation, electric control signal acquisition and data processing, which belong to the prior art and are not described in detail.

The invention is characterized in that: the ionization source comprises a cylindrical shell 5, a radio frequency power supply 2, an accelerating electrode 12, a radio frequency electrode 4 and a glass tube 3, wherein the circular accelerating electrode 12 is hermetically arranged at the front end of the cylindrical shell 5, and a sampling mechanism 13 extends into the cylindrical shell 5 from the side wall; as shown in figure 1, the sampling mechanism 13 is a sampling tube, as shown in figure 2, the sampling mechanism 13 is a sampling table, two radio frequency electrodes 4 are sleeved outside a glass tube 3, the radio frequency electrodes 4 are connected with a radio frequency power supply 2 through leads 1, the glass tube 3 is a quartz glass tube or a ceramic glass tube, the inner diameter of the glass tube is 1-2 mm, the wall thickness of the glass tube is 0.5-2 mm, and working gas is introduced into the glass tube.

The radio frequency electrodes 4 are circular rings, the distance between the two radio frequency electrodes 4 is 2-3 cm, and the distance between the radio frequency electrode 4 at the lower part and the bottom end of the glass tube 3 is less than 5 mm.

The dielectric barrier discharge ionization source ion mobility spectrometer shown in fig. 1 is used for directly testing a gas sample. The sampling mechanism 13 employs a sampling tube and is mounted on the cavity side wall of the cylindrical housing 5 of the ionization source, with the sampling tube extending into the cylindrical housing from the side wall. When the ionization source is used, working gas with stable flow rate is introduced into the glass tube 3, after the power supply is switched on, the working gas generates stable plasma inside the glass tube 3 and near the tail end through dielectric barrier discharge action, the plasma further generates reactant ions under the atmospheric pressure condition, a sample to be detected is introduced into the cylindrical shell 5 of the ionization source through the sampling tube, and the reactant ions and the sample to be detected generate molecular ion reaction to generate product ions of the sample to be detected. The product ions enter the ion reaction region under the boosting action of the accelerating electrode 12, under the action of an electric field, the product ions enter the drift region through the periodically opened ion gate 9, under the uniform electric field formed by the annular conductive ring 8 and the insulating ring 7, the product ions obtain energy from the electric field for directional drift on one hand, and on the other hand, the product ions continuously collide with neutral drift gas molecules flowing reversely to lose energy, and because the mass, the charged charges, the collision cross sections and the spatial configurations of the product ions are different, the respective migration rates in the electric field are different, so that different ions reach the signal acquisition part at different times and are separated.

The dielectric barrier discharge ionization source ion mobility spectrometer shown in fig. 2 is used for directly testing solid or liquid samples. The sampling mechanism is designed as a sample sampling platform and is used for bearing a solid or liquid sample. When the ion source device is used, a sample to be detected is placed into the ionization source device through the sampling platform, the sample is ionized by the ionization source to generate product ions, the product ions enter the ion reaction region through the boosting action of the accelerating electrode, under the action of an electric field, the product ions enter the drift region through the periodically opened ion gate, and finally reach the signal acquisition and data processing part under the uniform electric field formed by the insulating ring and the conducting ring. Because the mass, the charge, the collision cross section and the spatial configuration of the product ions are different, the respective migration rates in the electric field are different, so that different ions are separated by different arrival times at the signal acquisition part.

The above embodiments are preferred embodiments of the present invention, and those skilled in the art can make variations and modifications to the above embodiments, therefore, the present invention is not limited to the above embodiments, and any obvious improvements, substitutions or modifications made by those skilled in the art based on the present invention are within the protection scope of the present invention.

Claims

1. An ion mobility spectrometer of a dielectric barrier discharge ionization source, characterized in that: the ionization source comprises a cylindrical shell (5), a glass tube (3), a radio frequency electrode (4), a lead (1), a radio frequency power supply (2) and an accelerating electrode (12), wherein the ionization source comprises an ionization source, a drift tube (16) and a signal acquisition end (11), the drift tube (16) comprises a metal conducting ring (8) and an insulating ring (7), the metal conducting ring (8) and the insulating ring (7) are alternately connected, the ionization source comprises the cylindrical shell (5), the radio frequency power supply (2), the accelerating electrode (12), the radio frequency electrode (4), a quartz glass tube (3) and the accelerating electrode (12), the accelerating electrode (12) is hermetically arranged at the front end of the cylindrical shell (5), the quartz glass tube (3) is inserted into the cylindrical shell (5), the radio frequency electrodes (4) are two and are inserted into the cylindrical shell (5) and are sleeved on the outer wall of the quartz glass tube (3), the radio frequency electrode (4) is connected with a radio frequency power supply (2) through a wire (1), the quartz glass tube (3) contains working gas and further comprises a sampling mechanism (13), and the sampling mechanism (13) is arranged in the cylindrical shell (5).

2. The ion mobility spectrometer of the dielectric barrier discharge ionization source of claim 1, characterized in that: the front end of drift tube (16) is equipped with gas vent (6), the tail end of drift tube (16) is equipped with drift gas entry (10), the tail end of drift tube (16) still is equipped with signal acquisition end (11).

3. The ion mobility spectrometer of the dielectric barrier discharge ionization source of claim 1, characterized in that: the sampling mechanism (13) is a sampling tube.

4. The ion mobility spectrometer of the dielectric barrier discharge ionization source of claim 1, characterized in that: the sampling mechanism (13) is a sample sampling platform.

5. The ion mobility spectrometer of the dielectric barrier discharge ionization source of claim 1, characterized in that: the distance between the two radio frequency electrodes (4) is 2-3 cm, and the distance between the radio frequency electrode (4) at the lower part and the bottom end of the quartz glass tube (3) is less than 5 mm.

6. The ion mobility spectrometer of the dielectric barrier discharge ionization source of claim 1, characterized in that: the glass tube (3) is a quartz glass tube or a ceramic tube.

7. The ion mobility spectrometer of the dielectric barrier discharge ionization source of claim 1, characterized in that: the inner diameter of the glass tube (3) is 1-2 mm, and the wall thickness is 0.5-2 mm.