Double-repulsion-pole real-time electric field switching ion source

Abstract

The invention discloses a double-repulsion-pole real-time electric field switching ion source which can solve the problem that in the prior art, a gas chromatography mass spectrometer is low in detection efficiency. The ion source is located in the mass spectrometer body, a first separation mechanism and a second separation mechanism are arranged in an inner cavity of the gas chromatograph body, and the first separation mechanism and the second separation mechanism are used for separating two samples entering the gas chromatograph body respectively; a leading-in mechanism, an ionization mechanism and a mass analyzer are arranged in an inner cavity of the mass spectrometer body; the lead-in mechanism comprises a first lead-in port and a second lead-in port, the first lead-in port is connected with the first separation mechanism, the second lead-in port is connected with the second separation mechanism, and the first lead-in port and the second lead-in port are sequentially arranged on a passage of an electron beam emitted by the ionization mechanism; the ionization mechanism is used for emitting electron beams and utilizing the electron beams to bombard the sample introduced by the introduction mechanism to generate ion beams; and the mass analyzer is arranged on the path of the ion beam generated by the ionization mechanism.

Description

Technical Field

[0001] The present invention relates to the technical field of gas chromatography - mass spectrometry instruments, and particularly relates to a dual - repeller real - time electric - field switching ion source. Background Art

[0002] A gas chromatography - mass spectrometer is a combined instrument that combines the separation ability of a gas chromatograph and the selectivity, sensitivity, molecular mass, and molecular - structure identification ability of a mass spectrometer. When measuring a sample, a multi - component mixed gas is separated by a quartz capillary column of the gas chromatograph and then enters the ion source of the mass spectrometer. Under the bombardment of an electron beam, sample molecules are ionized to generate characteristic ions. The characteristic ions enter the mass analyzer under the action of the ion - lens electric field in the ion source and are separated according to the mass - to - charge ratio. Finally, a detector detects the signal intensities of different ions for qualitative and quantitative analysis.

[0003] However, the existing gas chromatography - mass spectrometry method has a long operation cycle, about 30 - 60 minutes, and only one sample can be analyzed in one run of an instrument. Therefore, at most 20 - 40 samples can be analyzed by one instrument in a day, and the sample - analysis efficiency is low. Summary of the Invention

[0004] In view of this, an embodiment of the present invention provides a dual - repeller real - time electric - field switching ion source, which can solve the problems in the prior art that the gas chromatography - mass spectrometer has a long operation cycle, only one sample can be analyzed in one run of an instrument, and the detection efficiency is low.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A dual - repeller real - time electric - field switching ion source is located inside the mass - spectrometer body, and further includes a gas - chromatograph body. It is characterized in that a first separation mechanism and a second separation mechanism are provided in the inner cavity of the gas - chromatograph body. The first separation mechanism and the second separation mechanism are used to separately separate two samples entering the gas - chromatograph body;

[0007] An introduction mechanism, an ionization mechanism, and a mass analyzer are provided in the inner cavity of the mass - spectrometer body;

[0008] The introduction mechanism includes a first introduction port and a second introduction port. The first introduction port is connected to the first separation mechanism, and the second introduction port is connected to the second separation mechanism. The first introduction port and the second introduction port are sequentially arranged on the path of the electron beam emitted by the ionization mechanism, and are used to separately introduce the samples separated by the first separation mechanism and the second separation mechanism;

[0009] The ionization mechanism is used to emit an electron beam and generate an ion beam by bombarding the sample introduced by the introduction mechanism with the electron beam;

[0010] The mass analyzer is arranged on the path of the ion beam generated by the ionization mechanism and is used for separating and detecting the ion beam.

[0011] As a further aspect of the present invention: The ionization mechanism includes an electron beam generating device, an ionization chamber, a transmission control device, and an ion beam transmission device;

[0012] The electron beam generating device is arranged on opposite sides of the introduction mechanism and is used for emitting the electron beam;

[0013] The ionization chamber includes a first ionization chamber and a second ionization chamber. The first ionization chamber is arranged in the space where the first introduction port is located, and the second ionization chamber is arranged in the space where the second introduction port is located, and is used for generating positive ions according to the electron beam bombarding the sample introduced by the introduction mechanism;

[0014] The transmission control device is arranged on the side of the ionization chamber far from the mass analyzer and is used for controlling the transmission of the positive ions generated by bombarding the sample in the ionization chamber;

[0015] The ion beam transmission device is connected to the mass analyzer and is used for forming an ion beam from the positive ions transmitted by the transmission control device and transmitting them.

[0016] As a further aspect of the present invention: The transmission control device includes a first repelling electrode, a second repelling electrode, and a single-pole double-throw switch;

[0017] The first repelling electrode is arranged on the side of the first ionization chamber far from the mass analyzer and is used for pushing the positive ions generated in the first ionization chamber towards the ion beam transmission device;

[0018] The second repelling electrode is arranged on the side of the second ionization chamber far from the mass analyzer and is used for pushing the positive ions generated in the second ionization chamber towards the ion beam transmission device;

[0019] The single-pole double-throw switch is respectively connected to the first repelling electrode and the second repelling electrode and is used for respectively controlling the connection of the first repelling electrode and the second repelling electrode.

[0020] As a further aspect of the present invention: The electron beam generating device includes a filament and a collector respectively arranged on both sides of the ionization chamber;

[0021] The filament is used for emitting electrons and forms an electron beam circuit with the collector.

[0022] As a further aspect of the present invention: The ion beam transmission device includes two first lenses and a second lens;

[0023] The two first lenses are respectively arranged on a side far from the transmission control device opposite to the first ionization chamber and the second ionization chamber. Each first lens is provided with a hole, and the positive ions generated by the first ionization chamber and the second ionization chamber are transmitted to the second lens through the holes of the first lens;

[0024] The second lens is arranged on the path between the first lens and the mass analyzer and is used for focusing the positive ions to form an ion beam.

[0025] As a further scheme of the present invention: an exhaust port is further arranged between the first ionization chamber and the second ionization chamber for discharging the un-ionized gas sample.

[0026] As a further scheme of the present invention: the first separation mechanism includes a first sample inlet, a first chromatographic column and a first transmission line;

[0027] The inlet of the first chromatographic column is connected to the first sample inlet through a pipeline and is used for chromatographically separating the sample entering from the first sample inlet;

[0028] The first transmission line is respectively connected to the outlet of the first chromatographic column and the first introduction port and is used for transmitting the sample separated by the first chromatographic column into the first introduction port;

[0029] The second separation mechanism includes a second sample inlet, a second chromatographic column and a second transmission line;

[0030] The inlet of the second chromatographic column is connected to the second sample inlet through a pipeline and is used for chromatographically separating the sample entering from the second sample inlet;

[0031] The second transmission line is respectively connected to the outlet of the second chromatographic column and the second introduction port and is used for transmitting the sample separated by the second chromatographic column into the second introduction port.

[0032] The beneficial effects of the present invention include but are not limited to:

[0033] (1) The novel dual-repeller real-time electric field switching ion source provided by the present invention can be configured with two sample analysis channels (dual sample inlets, dual chromatographic columns). The system includes a gas chromatograph and a mass spectrometer and can simultaneously analyze two samples (the column temperature programs in the method are the same). When sampling simultaneously through the dual sample inlets, the operating efficiency of the gas chromatography-mass spectrometry can be doubled, and the sample analysis cost per unit sample can be significantly reduced.

[0034] (2) In the dual-repeller real-time electric field switching ion source of the mass spectrometer of the present invention, the switching time between the two ion source chambers can be set according to requirements, which can ensure that there are sufficient mass spectrometry spectra and the number of sample collection points in the total ion current diagram on each sample channel for qualitative and quantitative calculations.

[0035] (3) The present invention only needs to upgrade the structure of the ion source in the gas chromatography - mass spectrometer, while the main structure of the gas chromatography - mass spectrometer remains unchanged. The upgrade is convenient and fast. After the upgrade, the sample analysis efficiency is equivalent to that of two gas chromatography - mass spectrometers, and the upgrade cost is much lower than that of purchasing another set of gas chromatography - mass spectrometers.

[0036] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings herein are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present invention and, together with the specification, are used to explain the principles of the present invention.

[0038] Figure 1 It is a schematic structural diagram of a double - repeller real - time electric - field switching ion source provided by an embodiment of the present invention;

[0039] In the figure: 1 - mass analyzer; 2 - first inlet; 3 - second inlet; 4 - first injection port; 5 - first chromatographic column; 6 - first transmission line; 7 - second injection port; 8 - second chromatographic column; 9 - second transmission line; 10 - first ionization chamber; 11 - second ionization chamber; 12 - first repeller; 13 - second repeller; 14 - single - pole double - throw switch; 15 - filament; 16 - collector; 17 - first lens; 18 - second lens; 19 - discharge port; 20 - carrier gas cylinder; 21 - pressure reducing valve; 22 - electronic pressure and flow controller. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The present invention will be further elaborated below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the protection scope of the present invention.

[0041] An embodiment of the present invention provides a double - repeller real - time electric - field switching ion source, as Figure 1 shown, located inside the mass spectrometer body, and further includes a gas chromatography instrument body. The inner cavity of the gas chromatography instrument body is provided with a first separation mechanism and a second separation mechanism. The first separation mechanism and the second separation mechanism are used to separately separate two samples entering the gas chromatography instrument body;

[0042] The inner cavity of the mass spectrometer body is provided with an introduction mechanism, an ionization mechanism, and a mass analyzer 1;

[0043] The introduction mechanism includes a first inlet 2 and a second inlet 3. The first inlet 2 is connected to the first separation mechanism, and the second inlet 3 is connected to the second separation mechanism. The first inlet 2 and the second inlet 3 are sequentially arranged on the path of the electron beam emitted by the ionization mechanism, and are used to separately introduce the samples separated by the first separation mechanism and the second separation mechanism;

[0044] An ionization mechanism for emitting an electron beam and bombarding a sample introduced by an introduction mechanism with the electron beam to generate an ion beam;

[0045] A mass analyzer 1 is arranged on the path of the ion beam generated by the ionization mechanism for separating and detecting the ion beam.

[0046] Further, the first separation mechanism includes a first sample inlet 4, a first chromatographic column 5, and a first transmission line 6;

[0047] The inlet of the first chromatographic column 5 is connected to the first sample inlet 4 through a pipeline for chromatographically separating the sample entering from the first sample inlet 4;

[0048] The first transmission line 6 is respectively connected to the outlet of the first chromatographic column 5 and the first introduction port 2 for transmitting the sample separated by the first chromatographic column 5 into the first introduction port 2;

[0049] The second separation mechanism includes a second sample inlet 7, a second chromatographic column 8, and a second transmission line 9;

[0050] The inlet of the second chromatographic column 8 is connected to the second sample inlet 7 through a pipeline for chromatographically separating the sample entering from the second sample inlet 7;

[0051] The second transmission line 9 is respectively connected to the outlet of the second chromatographic column 8 and the second introduction port 3 for transmitting the sample separated by the second chromatographic column 8 into the second introduction port 3.

[0052] In this embodiment, the first chromatographic column 5 and the second chromatographic column 8 may be the same or different. In actual use, when used as a standard method, the first chromatographic column 5 and the second chromatographic column 8 must be the same. In addition, in the present invention, when running two samples, since both the first chromatographic column 5 and the second chromatographic column 8 are in the gas chromatograph body, the column temperature program in the separation method needs to be the same.

[0053] Specifically, the sample can be injected simultaneously from the first sample inlet 4 and the second sample inlet 7. The compound is separated by the first chromatographic column 5 and the second chromatographic column 8 and enters the mass spectrometer through the first introduction port 2 and the second introduction port 3 for detection.

[0054] Further, the ionization mechanism includes an electron beam generating device, an ionization chamber, a transmission control device, and an ion beam transmission device;

[0055] The electron beam generating device is arranged on both sides opposite to the introduction mechanism for emitting an electron beam;

[0056] Ionization chamber, including a first ionization chamber 10 and a second ionization chamber 11. The first ionization chamber 10 is arranged in the space where the first inlet 2 is located, and the second ionization chamber 11 is arranged in the space where the second inlet 3 is located, and is used to generate positive ions according to the sample introduced by the electron beam bombardment introduction mechanism;

[0057] Transmission control device, arranged on the side of the ionization chamber away from the mass analyzer 1, and is used to control the transmission of the positive ions generated by the sample bombardment of the ionization chamber;

[0058] Ion beam transmission device, connected to the mass analyzer 1, and is used to form an ion beam from the positive ions transmitted by the transmission control device and perform transmission.

[0059] Furthermore, the electron beam generating device includes a filament 15 and a collector 16 respectively arranged on both sides of the ionization chamber;

[0060] The filament 15 is used to emit electrons and forms an electron beam circuit with the collector 16.

[0061] Specifically, after the filament 15 is energized and heated, electrons are emitted. The electrons generate an electron beam under the action of the electromagnetic field, and the electron beam reaches the collector 16 downward to form a circuit.

[0062] Furthermore, the transmission control device includes a first repelling electrode 12, a second repelling electrode 13 and a single-pole double-throw switch 14;

[0063] The first repelling electrode 12 is arranged on the side of the first ionization chamber 10 away from the mass analyzer 1, and is used to push the positive ions generated by the first ionization chamber 10 towards the ion beam transmission device;

[0064] The second repelling electrode 13 is arranged on the side of the second ionization chamber 11 away from the mass analyzer 1, and is used to push the positive ions generated by the second ionization chamber 11 towards the ion beam transmission device;

[0065] The single-pole double-throw switch 14 is respectively connected to the first repelling electrode 12 and the second repelling electrode 13, and is used to respectively control the connection of the first repelling electrode 12 and the second repelling electrode 13.

[0066] In this embodiment, the single-pole double-throw switch 14 is a single-pole double-throw voltage control switch. Specifically, the residence time t1 of the first repelling electrode 12, the switching time t2 from the first repelling electrode 12 to the second repelling electrode 13, the residence time t3 of the second repelling electrode 13, and the switching time t4 from the second repelling electrode 13 to the first repelling electrode 12 can be set. For example, t1 can be set to 150 ms, t2 to 10 ms, t3 to 150 ms, and t4 to 10 ms. During the time period t1, the single-pole double-throw switch 14 is connected to the first repelling electrode 12. There is a repelling voltage on the first repelling electrode 12 and no repelling voltage on the second repelling electrode 13. Only the compound positive ions in the first ionization chamber 10 will be pushed by the electric field towards the ion beam transmission device. The data collected on the mass analyzer 1 during this time period is the data of the sample in the first inlet 2. During the time period t3, the single-pole double-throw switch 14 is connected to the second repelling electrode 13. There is a repelling voltage on the second repelling electrode 13 and no repelling voltage on the first repelling electrode 12. Only the compound positive ions in the second ionization chamber 11 will be pushed by the electric field towards the ion beam transmission device. The data collected on the mass analyzer 1 during this time period is the data of the sample in the second inlet 3. The data collected during the switching time periods t2 and t4 is not used for calculation.

[0067] Further, the ion beam transmission device includes two first lenses 17 and a second lens 18;

[0068] The two first lenses 17 are respectively arranged on the side away from the transmission control device opposite to the first ionization chamber 10 and the second ionization chamber 11. Each first lens 17 is provided with a hole. The positive ions generated by the first ionization chamber 10 and the second ionization chamber 11 are transmitted through the holes of the first lenses 17 to the second lens 18;

[0069] The second lens 18 is arranged on the path between the first lens 17 and the mass analyzer 1 and is used for focusing the positive ions to form an ion beam.

[0070] In this embodiment, when the electron beam passes through the first ionization chamber 10 and the second ionization chamber 11 of the ion source, it bombards the compound molecules to generate positive ion fragments or molecular ions. Under the action of the positive electric field of the first repelling electrode 12 and the second repelling electrode 13, it moves towards the two first lenses 17. Under the action of the first lenses 17, it passes through the round holes on the first lenses 17. Under the action of the second lens 18, it is focused into an ion beam and enters the mass analyzer 1 to be separated according to the mass-to-charge ratio and detect the relative intensity of the corresponding ions.

[0071] Further, a discharge port 19 is also arranged between the first ionization chamber 10 and the second ionization chamber 11 for discharging the un-ionized gas sample.

[0072] Specifically, the round holes of the electron channels between the first ionization chamber 10 and the second ionization chamber 11 are opposite to each other. Under the action of external high vacuum, the un-ionized sample gas overflows from the round holes and is discharged through the discharge port 19, and then is pumped out by the mass spectrometer vacuum system.

[0073] For the dual-repeller real-time electric field switching ion source provided by the present invention, carrier gas is provided by a carrier gas cylinder 20. After the carrier gas passes through a pressure reducing valve 21 and an electronic pressure and flow controller 22 to further adjust the pressure and flow rate, a part of the carrier gas and the sample entering through the first sampling port 4 enter the first chromatographic column 5 for separation, and are transmitted to the first introduction port 2 in the mass spectrometer through the first transmission line 6. Another part of the carrier gas and the sample entering through the second sampling port 7 enter the second chromatographic column 8 for separation, and are transmitted to the second introduction port 3 in the mass spectrometer through the second transmission line 9.

[0074] After the filament 15 is energized and heated, electrons are emitted. Under the action of the electromagnetic field, an electron beam is generated. The electron beam reaches the collector 16 downward to form a loop. When the electron beam passes through the first ionization chamber 10 and the second ionization chamber 11 of the ion source, it bombards the compound molecules to generate positive ion fragments or molecular ions. When the single-pole double-throw switch 14 is connected to the first repeller 12 and the first repeller 12 stays for a time period t1, there is a repelling voltage on the first repeller 12 and no repelling voltage on the second repeller 13. The positive ions of the compounds in the first ionization chamber 10 will be pushed by the electric field towards the corresponding first lens 17. Under the action of the first lens 17, they pass through the round hole on the first lens 17 and are focused into an ion beam under the action of the second lens 18, and enter the mass analyzer 1 to be separated according to the mass-to-charge ratio and detect the relative intensity of the corresponding ions. The data collected on the mass analyzer 1 during this time period is the data of the sample in the first sampling port 4. When the single-pole double-throw switch 14 is connected to the second repeller 13 and the second repeller 13 stays for a time period t3, there is a repelling voltage on the second repeller 13 and no repelling voltage on the first repeller 12. The positive ions of the compounds in the second ionization chamber 11 will be pushed by the electric field towards the corresponding first lens 17. Under the action of the first lens 17, they pass through the round hole on the first lens 17 and are focused into an ion beam under the action of the second lens 18, and enter the mass analyzer 1 to be separated according to the mass-to-charge ratio and detect the relative intensity of the corresponding ions. The data collected on the mass analyzer 1 during this time period is the data of the sample in the second sampling port 7. The data collected during the switching time periods t2 and t4 is not used for calculation. The data of the time period t1 extracted from the original data and integrated is the mass spectrometry data of the sample in the first sampling port 4, and the data of the time period t3 extracted from the original data and integrated is the mass spectrometry data of the sample in the second sampling port 7. And the round holes are opposite to each other. Under the action of external high vacuum, the un-ionized sample gas overflows from the electron channel between the first ionization chamber 10 and the second ionization chamber 11, is discharged through the discharge port 19, and then is pumped out by the mass spectrometer vacuum system.

[0075] Other embodiments of the present invention will be readily apparent to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of the invention following the general principles of the invention and including known common general knowledge or conventional technical means in the technical field not disclosed herein. The specification and examples are to be considered as illustrative only, and the true scope and spirit of the invention are pointed out by the following claims.

[0076] It should be understood that the present invention is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A dual-repulsion-pole real-time electric field switching ion source, located inside the mass spectrometer body, and further including a gas chromatograph body, characterized in that, The inner cavity of the gas chromatograph body is provided with a first separation mechanism and a second separation mechanism, and the first separation mechanism and the second separation mechanism are used to separately separate two samples entering the gas chromatograph body; The inner cavity of the mass spectrometer body is provided with an introduction mechanism, an ionization mechanism, and a mass analyzer; The introduction mechanism includes a first introduction port and a second introduction port. The first introduction port is connected to the first separation mechanism, the second introduction port is connected to the second separation mechanism, and the first introduction port and the second introduction port are sequentially arranged on the path of the electron beam emitted by the ionization mechanism; The ionization mechanism is used to emit an electron beam and generate an ion beam by bombarding the sample introduced by the introduction mechanism with the electron beam; The mass analyzer is arranged on the path of the ion beam generated by the ionization mechanism.

2. The dual-repulsion-pole real-time electric field switching ion source according to claim 1, characterized in that, The ionization mechanism includes an electron beam generating device, an ionization chamber, a transmission control device, and an ion beam transmission device; The electron beam generating device is arranged on both sides opposite to the introduction mechanism and is used to emit the electron beam; The ionization chamber includes a first ionization chamber and a second ionization chamber. The first ionization chamber is arranged in the space where the first introduction port is located, and the second ionization chamber is arranged in the space where the second introduction port is located and is used to generate positive ions by bombarding the sample introduced by the introduction mechanism with the electron beam; The transmission control device is arranged on the side of the ionization chamber away from the mass analyzer and is used to control the transmission of the positive ions generated by bombarding the sample in the ionization chamber; The ion beam transmission device is connected to the mass analyzer and is used to form an ion beam from the positive ions transmitted by the transmission control device and transmit them.

3. The dual-repulsion-pole real-time electric field switching ion source according to claim 2, characterized in that, The transmission control device includes a first repelling electrode, a second repelling electrode, and a single-pole double-throw switch; The first repelling electrode is arranged on the side of the first ionization chamber away from the mass analyzer and is used to push the positive ions generated by the first ionization chamber towards the ion beam transmission device; The second repelling electrode is arranged on the side of the second ionization chamber away from the mass analyzer and is used to push the positive ions generated by the second ionization chamber towards the ion beam transmission device; The single-pole double-throw switch is respectively connected to the first repelling electrode and the second repelling electrode and is used to respectively control the connection of the first repelling electrode and the second repelling electrode.

4. The dual-repulsion-pole real-time electric field switching ion source according to claim 2, characterized in that, The electron beam generating device includes a filament and a collector respectively arranged on both sides of the ionization chamber; The filament is used to emit electrons and forms an electron beam circuit with the collector.

5. The dual-repulsion-pole real-time electric field switching ion source according to claim 2, characterized in that, The ion beam transmission device includes two first lenses and a second lens; The two first lenses are respectively arranged on the side away from the transmission control device opposite to the first ionization chamber and the second ionization chamber. Each first lens is provided with a hole, and the positive ions generated by the first ionization chamber and the second ionization chamber are transmitted to the second lens through the hole of the first lens; The second lens is arranged on the path between the first lens and the mass analyzer and is used to focus the positive ions to form an ion beam.

6. The dual-repulsion-pole real-time electric field switching ion source according to claim 2, characterized in that, A discharge port is also provided between the first ionization chamber and the second ionization chamber for discharging the un-ionized gas sample.

7. The dual-repulsion-pole real-time electric field switching ion source according to claim 1, characterized in that, The first separation mechanism includes a first sample inlet, a first chromatographic column, and a first transmission line; The inlet of the first chromatographic column is connected to the first sample inlet through a pipeline; The first transmission line is respectively connected to the outlet of the first chromatographic column and the first introduction port; The second separation mechanism includes a second sample inlet, a second chromatographic column, and a second transmission line; The inlet of the second chromatographic column is connected to the second sample inlet through a pipeline; The second transmission line is respectively connected to the outlet of the second chromatographic column and the second introduction port.

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