Low-vacuum heating photo ionization source device

Abstract

The invention relates to the technical field of mass spectrum analyzers, in particular to a low-vacuum heating photo ionization source device which comprises a cavity, a sample introduction pipeline, a sample introduction pipeline fixing piece, a transmission electrode, an extraction electrode, a vacuum ultraviolet light source and a mass spectrometer and further comprises a sample introduction fixing piece provided with a heating rod, a transmission electrode and an extraction electrode. And a ceramic heating pipe and a thermal insulation sleeve are also arranged on the sample injection pipeline. According to the invention, the heating rod is adopted to heat the sample introduction fixing sheet, the transmission electrode and the extraction electrode respectively, and the ceramic heating pipe is adopted to heat the sample introduction pipeline, so that the heating of the photoionization source under a low vacuum condition is realized, the heating temperature can reach 500 DEG C, and the problem of adsorption residues in the sample introduction pipeline and the ionization source during detection of a high-boiling-point compound can be solved; and the problem that a light window of a vacuum ultraviolet light source is polluted when high-boiling-point substances are detected is solved.

Description

Technical Field

[0001] The invention relates to the technical field of mass spectrometers, in particular to a low vacuum heating photoionization source device. Background Art

[0002] The following issues should be paid attention to when heating the ionization source of a low vacuum photoionization mass spectrometer: (1) Thermal insulation design between the ionization source and the rear-end cavity: The heat conduction of the ionization source causes the rear-end mass spectrometer cavity connected to the ionization source to overheat. Due to excessive heat loss, the heating power is insufficient and the ionization source cannot reach the preset heating temperature. (2) Insulation design: When using heating rods and temperature sensors, short circuits need to be avoided when these components are connected to the ionization source cavity and electrodes. (3) Thermal insulation design: Excessive heat loss needs to be prevented.

[0003] When a low vacuum photoionization mass spectrometer is used to detect high-boiling-point compounds, adsorption residues may occur in the injection line and the ionization source, and the optical window of the vacuum ultraviolet light source may be contaminated. Summary of the invention

[0004] In view of the above problems, an object of the present invention is to provide a low vacuum heating photoionization source device.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A low vacuum heating photoionization source device comprises a cavity, a sample injection pipeline, a sample injection pipeline fixing plate, a transmission electrode, an extraction electrode, a vacuum ultraviolet light source and a mass spectrometer;

[0007] One end of the cavity has an opening, and a heat-insulating ceramic plate A for closing the opening is provided on the opening of the cavity, and a side of the heat-insulating ceramic plate A away from the cavity is connected to the mass spectrometer;

[0008] The sample injection pipeline fixing plate is arranged inside the cavity and located on a side away from the heat insulating ceramic plate A, one end of the sample injection pipeline is fixed on the sample injection pipeline fixing plate, and the other end of the sample injection pipeline passes through the other end of the cavity;

[0009] The transmission electrode and the extraction electrode are respectively arranged inside the cavity between the thermal insulation ceramic plate A and the sample injection pipeline fixing plate, the extraction electrode is located on the side close to the thermal insulation ceramic plate A, a conical channel is provided on the extraction electrode, the opening of the end with a larger diameter of the conical channel is opposite to the sample input end of the mass spectrometer, and the opening of the end with a smaller diameter of the conical channel is toward one end of the sample injection pipeline, the transmission electrode is located on the side away from the thermal insulation ceramic plate A, the transmission electrode has a cavity inside, and a through hole A and a through hole B connected to the cavity are provided on the transmission electrode, and the axial center line of the through hole A, the axial center line of the conical channel and the axial center line of one end of the sample injection pipeline are collinear;

[0010] A heating rod and a temperature sensor are respectively embedded in the interior of the sample injection pipeline fixing plate, the interior of the transmission electrode and the interior of the extraction electrode;

[0011] The vacuum ultraviolet light source is installed on the cavity, and the light emitted by the vacuum ultraviolet light source passes through the through hole B and irradiates into the cavity of the transmission electrode.

[0012] The through hole B is opened on the side surface of the transmission electrode, and the axial center line of the through hole B is perpendicular to the axial center line of the through hole A.

[0013] The projection of the length direction of each heating rod in the horizontal plane and the projection of the length direction of each temperature sensor in the horizontal plane are both perpendicular to the projection of the axial center line of the through hole A in the horizontal plane.

[0014] A heat insulating material is provided on the inner side of the cavity.

[0015] The outer circumference of the sample inlet pipeline is also sheathed with a ceramic heating tube.

[0016] A heat-insulating sleeve is also arranged on the outer side of the ceramic heating tube, the interior of the heat-insulating sleeve is filled with heat-insulating material, and the outer side surface of the heat-insulating sleeve is sealed and connected to the cavity.

[0017] The insulating ceramic plate A is provided with a plurality of mounting columns, the axial center line of each mounting column is parallel to the axial center line of the through hole A, one end of each mounting column is respectively connected to the mass spectrometer, and the other end of each mounting column is respectively connected to the sample injection pipeline fixing plate.

[0018] A heat-insulating ceramic plate B is provided between the sample injection pipeline fixing plate and the transmission electrode, and a heat-insulating ceramic plate C is provided between the transmission electrode and the extraction electrode.

[0019] A sealing ring is also provided between the insulating ceramic plate B and the transmission electrode, a sealing ring is also provided between the transmission electrode and the insulating ceramic plate C, a sealing ring is also provided between the insulating ceramic plate C and the extraction electrode, a sealing ring is also provided between the extraction electrode and the insulating ceramic plate A, and a sealing ring is also provided between the insulating ceramic plate A and the outer casing of the mass spectrometer.

[0020] The voltages applied to the transmission electrode and the extraction electrode are successively reduced, and an axial electric field of 1-50 V / cm is formed along the injection direction of the injection pipeline.

[0021] The advantages and positive effects of the present invention are:

[0022] The present invention is based on vacuum ultraviolet photoionization technology and proposes a low vacuum heating photoionization source device, which can not only adjust the temperature of the photoionization source within the range of room temperature to 500°C, but also avoid the overheating of the rear-end cavity affecting the performance, and can effectively solve the adsorption residue problem during the detection of high-boiling point compounds and the light window pollution problem of the vacuum ultraviolet lamp. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention;

[0024] Figure 2 It is a schematic diagram of the installation position of the heating rod and the temperature sensor of the present invention.

[0025] In the figure: 1 is a cavity, 2 is a sample injection pipeline, 3 is a sample injection pipeline fixing plate, 4 is a transmission electrode, 5 is an extraction electrode, 6 is a vacuum ultraviolet light source, 7 is a heat-insulating ceramic plate A, 8 is a heating rod, 9 is a temperature sensor, 10 is a ceramic heating tube, 11 is a heat-insulating sleeve, 12 is a mounting column, 13 is a heat-insulating ceramic plate B, 14 is a heat-insulating ceramic plate C, and 15 is a sealing ring. DETAILED DESCRIPTION

[0026] The following is combined with Figure 1-2 The present invention is further described in detail.

[0027] A low vacuum heating photoionization source device, such as Figure 1-2 As shown, the present embodiment includes a cavity 1, a sample injection pipeline 2, a sample injection pipeline fixing plate 3, a transmission electrode 4, an extraction electrode 5, a vacuum ultraviolet light source 6 and a mass spectrometer. In the present embodiment, the vacuum ultraviolet light source 6 and the mass spectrometer are both commercially available products or self-developed products, the mass spectrometer can be a time-of-flight mass spectrometer, a quadrupole mass spectrometer or an ion trap mass spectrometer, and the vacuum ultraviolet light source 6 is a gas discharge lamp light source with a light window.

[0028] One end of the cavity 1 has an opening, and a heat-insulating ceramic plate A 7 for sealing the opening is provided on the opening of the cavity 1 , and a side of the heat-insulating ceramic plate A 7 away from the cavity 1 is connected to the mass spectrometer.

[0029] The sampling pipeline fixing plate 3 is arranged inside the cavity 1 and located on a side away from the insulating ceramic plate A 7. One end of the sampling pipeline 2 is sealed and fixed on the sampling pipeline fixing plate 3, and the other end of the sampling pipeline 2 passes through the other end of the cavity 1.

[0030] The transmission electrode 4 and the extraction electrode 5 are respectively arranged inside the cavity 1 between the heat-insulating ceramic plate A7 and the sample injection pipeline fixing plate 3. The extraction electrode 5 is located on the side close to the heat-insulating ceramic plate A7. A conical channel is opened on the extraction electrode 5. The end with a larger diameter of the conical channel is opposite to the sample input end of the mass spectrometer, and the end with a smaller diameter of the conical channel is opened toward one end of the sample injection pipeline 2. The transmission electrode 4 is located on the side away from the heat-insulating ceramic plate A7. The transmission electrode 4 has a cavity inside. The transmission electrode 4 is provided with a through hole A and a through hole B connected to the cavity. The axial center line of the through hole A, the axial center line of the conical channel and the axial center line of one end of the sample injection pipeline 2 are collinear. In this embodiment, the sample injection pipeline fixing plate 3, the transmission electrode 4 and the extraction electrode 5 are all circular metal plates with central openings, and the interval between them is 4 mm; the inner diameter of the transmission electrode 4 is 20 mm, the aperture of the through hole A is 4 mm, and the aperture of the through hole B is 6 mm.

[0031] A heating rod 8 and a temperature sensor 9 are respectively embedded inside the sample inlet pipe fixing plate 3, inside the transmission electrode 4 and inside the extraction electrode 5. The heating rod 8 is used to adjust the internal temperature of the ionization source, which can be adjusted from room temperature to 500°C. In this embodiment, the operating temperature of the ionization source is 200°C.

[0032] The vacuum ultraviolet light source 6 is installed on the cavity 1 , and the light emitted by the vacuum ultraviolet light source 6 passes through the through hole B and irradiates into the cavity of the transmission electrode 4 .

[0033] Specifically, in this embodiment, the through hole B is opened on the side of the transmission electrode 4, and the axial center line of the through hole B is perpendicular to the axial center line of the through hole A. Figure 2 As shown, the light irradiation direction (Y direction) of the vacuum ultraviolet light source 6 is perpendicular to the injection direction (X direction) of the injection pipeline 2.

[0034] Specifically, in this embodiment, the projection of the length direction of each heating rod 8 in the horizontal plane and the projection of the length direction of each temperature sensor 9 in the horizontal plane are both perpendicular to the projection of the axial center line of the through hole A in the horizontal plane. Figure 1 and Figure 2 As shown, the length direction of each heating rod 8 and the length direction of each temperature sensor 9 are parallel to the Y direction. In this embodiment, the heating rod 8 and the temperature sensor 9 are both commercially available products, and are respectively connected to an external controller.

[0035] Specifically, in this embodiment, a heat insulating material, such as a heat insulating polyethylene material, is provided on the inner side of the cavity 1 to keep the ionization source warm.

[0036] Specifically, in this embodiment, the outer periphery of the sample inlet pipeline 2 is also sleeved with a ceramic heating tube 10, and the outer side of the ceramic heating tube 10 is also provided with a heat preservation sleeve 11, the interior of the heat preservation sleeve 11 is filled with heat preservation material, and the outer side of the heat preservation sleeve 11 is sealed and connected to the cavity 1. In this embodiment, the ceramic heating tube 10 is a commercially available product, and its action is controlled by an external controller; the setting structure of the heat preservation sleeve 11 adopts the existing technology. Through the coordinated setting of the ceramic heating tube 10 and the heat preservation sleeve 11, the sample inlet pipeline 2 can be fully heated and insulated.

[0037] Specifically, in this embodiment, a plurality of metal mounting columns 12 are provided on the insulating ceramic plate A 7, and the axial center line of each mounting column 12 is parallel to the axial center line of the through hole A. One end of each mounting column 12 is respectively connected to the mass spectrometer, and the other end of each mounting column 12 is respectively connected to the sample injection pipeline fixing plate 3, so the installation is convenient and reliable.

[0038] Specifically, in this embodiment, a heat-insulating ceramic plate B13 is provided between the sample injection pipeline fixing plate 3 and the transmission electrode 4, a heat-insulating ceramic plate C14 is provided between the transmission electrode 4 and the extraction electrode 5, a sealing ring 15 is also provided between the heat-insulating ceramic plate B13 and the transmission electrode 4, a sealing ring 15 is also provided between the transmission electrode 4 and the heat-insulating ceramic plate C14, a sealing ring 15 is also provided between the heat-insulating ceramic plate C14 and the extraction electrode 5, a sealing ring 15 is also provided between the extraction electrode 5 and the heat-insulating ceramic plate A7, and a sealing ring 15 is also provided between the heat-insulating ceramic plate A7 and the housing of the mass spectrometer. In this embodiment, the sealing rings 15 are all commercially available high-temperature resistant O-rings. Through the coordinated arrangement of the heat-insulating ceramic plate A7, the heat-insulating ceramic plate B13, the heat-insulating ceramic plate C14 and the sealing rings 15, the heat-insulating sealing effect between the sample injection pipeline fixing plate 3, the transmission electrode 4, and the extraction electrode 5 is effectively guaranteed, and the mass spectrometer is insulated, so as to ensure the stability of the internal air pressure of the ionization source cavity 1. The internal air pressure of the ionization source cavity 1, that is, the internal air pressure of the transmission electrode 4, needs to be maintained between 0.01-1000 Pa, and is controlled at about 30 Pa in this embodiment.

[0039] Specifically, in this embodiment, the voltages applied to the transmission electrode 4 and the extraction electrode 5 are successively reduced, and an axial electric field of 20 V / cm is formed along the injection direction (X direction) of the injection pipeline 2 .

[0040] Working principle:

[0041] After the ionization source is heated to the set temperature by the heating rod 8 and the ceramic heating tube 10, the high boiling point compound to be ionized enters the interior of the ionization source through the sampling pipeline 2, enters the cavity of the transmission electrode 4 through the through hole A of the transmission electrode 4, and is immediately ionized by the ultraviolet light emitted by the vacuum ultraviolet light source 6. The ions generated by the ionization move forward under the action of the electric field and enter the mass spectrometer for detection; the heating rod 8 is used to heat the sampling fixing plate 3, the transmission electrode 4, and the extraction electrode 5 respectively, and the ceramic heating tube 10 is also used to heat the sampling pipeline 2, so that the heating of the photoionization source under low vacuum conditions is realized, and the heating temperature can reach 500°C, which can solve the problem of adsorption residue in the sampling pipeline and the ionization source when detecting high boiling point compounds, and solve the problem of light window pollution of the vacuum ultraviolet light source 6 when detecting high boiling point substances.

Claims

1. A low vacuum heating photoionization source device, characterized in that: It comprises a cavity (1), a sample injection pipeline (2), a sample injection pipeline fixing plate (3), a transmission electrode (4), an extraction electrode (5), a vacuum ultraviolet light source (6) and a mass spectrometer; One end of the cavity (1) has an opening, and a heat-insulating ceramic plate A (7) for sealing the opening is provided on the opening of the cavity (1), and a side of the heat-insulating ceramic plate A (7) away from the cavity (1) is connected to the mass spectrometer; The sample injection pipeline fixing plate (3) is arranged inside the cavity (1) and located on a side away from the heat-insulating ceramic plate A (7); one end of the sample injection pipeline (2) is fixed on the sample injection pipeline fixing plate (3), and the other end of the sample injection pipeline (2) passes through the other end of the cavity (1); The transmission electrode (4) and the extraction electrode (5) are respectively arranged inside the cavity (1) between the heat-insulating ceramic plate A (7) and the sample injection pipeline fixing plate (3); the extraction electrode (5) is located on a side close to the heat-insulating ceramic plate A (7); a conical channel is provided on the extraction electrode (5); the end with a larger diameter of the conical channel is opened opposite to the sample input end of the mass spectrometer; the end with a smaller diameter of the conical channel is opened toward one end of the sample injection pipeline (2); the transmission electrode (4) is located on a side away from the heat-insulating ceramic plate A (7); the transmission electrode (4) has a cavity inside; a through hole A and a through hole B connected to the cavity are provided on the transmission electrode (4); the axial center line of the through hole A, the axial center line of the conical channel and the axial center line of one end of the sample injection pipeline (2) are collinear; A heating rod (8) and a temperature sensor (9) are respectively embedded in the interior of the sample injection pipeline fixing plate (3), the interior of the transmission electrode (4), and the interior of the extraction electrode (5); The vacuum ultraviolet light source (6) is mounted on the cavity (1), and the light emitted by the vacuum ultraviolet light source (6) passes through the through hole B and irradiates the cavity of the transmission electrode (4).

2. A low vacuum heating photoionization source device according to claim 1, characterized in that: The through hole B is opened on the side surface of the transmission electrode (4), and the axial center line of the through hole B is perpendicular to the axial center line of the through hole A.

3. A low vacuum heating photoionization source device according to claim 1, characterized in that: The projection of the length direction of each heating rod (8) in the horizontal plane and the projection of the length direction of each temperature sensor (9) in the horizontal plane are both perpendicular to the projection of the axial center line of the through hole A in the horizontal plane.

4. A low vacuum heating photoionization source device according to claim 1, characterized in that: A heat insulating material is provided on the inner side surface of the cavity (1).

5. A low vacuum heating photoionization source device according to claim 1, characterized in that: The outer circumference of the sample inlet pipeline (2) is also sheathed with a ceramic heating tube (10).

6. A low vacuum heating photoionization source device according to claim 5, characterized in that: A heat-insulating sleeve (11) is also provided on the outside of the ceramic heating tube (10), the interior of the heat-insulating sleeve (11) is filled with heat-insulating material, and the outer side surface of the heat-insulating sleeve (11) is sealed and connected to the cavity (1).

7. A low vacuum heating photoionization source device according to claim 1, characterized in that: A plurality of mounting columns (12) are provided on the thermal insulation ceramic plate A (7), and the axial center line of each mounting column (12) is parallel to the axial center line of the through hole A. One end of each mounting column (12) is respectively connected to the mass spectrometer, and the other end of each mounting column (12) is respectively connected to the sample injection pipeline fixing plate (3).

8. A low vacuum heating photoionization source device according to claim 1, characterized in that: A heat-insulating ceramic plate B (13) is provided between the sample injection pipeline fixing plate (3) and the transmission electrode (4), and a heat-insulating ceramic plate C (14) is provided between the transmission electrode (4) and the extraction electrode (5).

9. A low vacuum heating photoionization source device according to claim 8, characterized in that: A sealing ring (15) is also provided between the thermal insulation ceramic plate B (13) and the transmission electrode (4), a sealing ring (15) is also provided between the transmission electrode (4) and the thermal insulation ceramic plate C (14), a sealing ring (15) is also provided between the thermal insulation ceramic plate C (14) and the extraction electrode (5), a sealing ring (15) is also provided between the extraction electrode (5) and the thermal insulation ceramic plate A (7), and a sealing ring (15) is also provided between the thermal insulation ceramic plate A (7) and the outer shell of the mass spectrometer.

10. A low vacuum heating photoionization source device according to claim 1, characterized in that: The voltages applied to the transmission electrode (4) and the extraction electrode (5) are successively reduced, and an axial electric field of 1-50 V / cm is formed along the injection direction of the injection pipeline (2).

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