Mass spectrum ion source for ultra-high pressure sample introduction

Abstract

The invention provides a mass spectrum ion source for ultrahigh air pressure sample introduction, which is suitable for ultrahigh air pressure (the air pressure is hundred MPa level) scenes, and comprises a conduction optical fiber, a laser, a capillary tube, an ionization chamber and an ion lens, a conduction optical fiber is arranged in the capillary tube, and a filling layer is arranged in an annular space between the conduction optical fiber and the inner wall of the capillary tube; the tube wall of the capillary tube is made of a high-pressure permeable material; one end of the capillary tube extends into the ionization chamber and is communicated with a sample inlet of the ionization chamber; a nano-silver coating layer is arranged at the end part of the conductive optical fiber at the end; positive high voltage is provided for the nano-silver coating layer by a positive high-voltage electrode; the laser is used for emitting laser to the conduction optical fiber, and the conduction optical fiber is used for guiding the laser to reach the nano-silver coating layer; a magnet for providing a magnetic field is arranged outside the ionization chamber; and an ion lens is arranged at a sample outlet of the ionization chamber.

Description

Technical Field

[0001] The invention relates to a mass spectrometry ion source, in particular to a mass spectrometry ion source for sample injection in an ultra-high pressure environment, and belongs to the technical field of mass spectrometry. Background Art

[0002] Existing mass spectrometry technology is widely used for online measurement of gases in industrial pipelines; mass spectrometry requires an ion source based on the principles of EI, CI, PEI, etc. as an ionization method. The ion source is also the interface transition link between the injection pipeline and the high vacuum inside the mass spectrometer. If the interface is not designed properly, it may cause distortion or contamination of the ion spectrum peak, or even damage the vacuum or even burn the instrument. The gas pressure in industrial pipelines is MPa or even hundreds of MPa, which is difficult to measure using mass spectrometry injection.

[0003] At present, the conventional method for mass spectrometry measurement of industrial pressure pipelines is pressure relief measurement, which releases the ultra-high pressure to atmospheric pressure and then uses an auxiliary high vacuum pump to extract the vacuum to less than 0.1 Pa. This method will lose the original information, thereby reducing the credibility of the measurement results; and it has a large volume and power consumption, which is not conducive to the miniaturization and integration of instruments and equipment.

[0004] In addition, existing ion sources mostly use a gas chamber plus filament structure, which has high requirements for environmental vacuum and small sample volume, and cannot be used in ultra-high pressure (gas pressure is at the level of hundreds of MPa) scenarios. Summary of the invention

[0005] In view of this, the present invention provides a mass spectrometry ion source for ultra-high pressure injection, which is suitable for ultra-high pressure scenarios (pressure is at the level of hundreds of MPa). It can allow ultra-high pressure molecules to enter an ionization chamber through a capillary with a specially designed structure, generate charged ions in the ionization chamber, and provide a stable and high-intensity original signal for subsequent mass spectrometry detection, thereby improving the mass spectrometry detection limit and detection accuracy.

[0006] The technical solution of the present invention is: a mass spectrometer ion source for ultra-high pressure injection, comprising: a transmission optical fiber, a laser, a capillary, an ionization chamber and an ion lens;

[0007] A conducting optical fiber is arranged inside the capillary tube, and a filling layer is arranged in the annular space between the conducting optical fiber and the inner wall of the capillary tube; the tube wall of the capillary tube is a high-pressure permeable material;

[0008] One end of the capillary extends into the interior of the ionization chamber and is connected to the sample inlet of the ionization chamber; and a nano silver coating layer is provided at the end of the conductive optical fiber at this end; the nano silver coating layer is provided with a positive high voltage by a positive high voltage electrode;

[0009] The laser is used to emit laser light to the transmission optical fiber, and the transmission optical fiber is used to guide the laser light to the nano silver coating layer;

[0010] A magnet for providing a magnetic field is arranged outside the ionization chamber; an ion lens is arranged at the sample outlet of the ionization chamber.

[0011] As a preferred embodiment of the present invention, it also includes a fiber collimator for adjusting the light output angle of the laser.

[0012] As a preferred embodiment of the present invention: the outer wall of the conductive optical fiber has an optical fiber reflective coating.

[0013] As a preferred embodiment of the present invention: the filling layer is silicon dioxide.

[0014] As a preferred embodiment of the present invention, the conductive optical fiber, the nano silver coating and the ion focusing hole of the ion lens are coaxial.

[0015] Beneficial effects:

[0016] (1) The ion source of the present invention adopts the method of penetrating material + laser irradiation + high voltage discharge to allow ultra-high pressure molecules to enter the ionization chamber through a capillary with a specially designed structure, generate charged ions in the ionization chamber, and provide a stable and high-intensity original signal for subsequent mass spectrometry detection, thereby improving the mass spectrometry detection limit and detection accuracy; the ion source can work stably under an ultra-high pressure of 100MPa.

[0017] (2) In the present invention, the optical path is changed by changing the laser incident angle through the optical fiber collimator, which can reduce the number of reflections of the laser in the transmission optical fiber.

[0018] (3) In the present invention, the outer wall of the transmission optical fiber has an optical fiber reflective coating, which can prevent the laser from scattering out of the optical fiber and preserve the energy of the laser as much as possible.

[0019] (4) In the present invention, the laser, the nanosilver coating with positive high pressure and the ion focusing hole of the ion lens are in the same straight line, which can effectively accelerate the ions and guide the ion flow into an ultra-high vacuum environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the use of the mass spectrometry ion source of the present invention;

[0021] Figure 2 is a cross-sectional view of an ion source of the present invention;

[0022] Figure 3 It is a cross-sectional view of the capillary of the present invention.

[0023] Wherein: 1-fiber collimator, 2-conduction fiber, 3-fiber reflection coating, 4-filling layer, 5-nano silver coating, 6-capillary, 7-positive high-voltage electrode, 8-magnet, 9-ion lens, 10-ionization chamber. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

[0025] The present embodiment provides a mass spectrometry ion source for ultra-high pressure injection, which adopts the method of permeable material + laser irradiation + high voltage discharge to allow ultra-high pressure molecules to enter the ionization chamber through a capillary with a specially designed structure, and generate charged ions in the ionization chamber, thereby providing a stable and high-intensity original signal for subsequent mass spectrometry detection, thereby improving the mass spectrometry detection limit and detection accuracy.

[0026] like Figure 1-Figure 3 As shown, the mass spectrometry ion source includes: a fiber collimator 1, a transmission fiber 2, a laser, a capillary 6, an ionization chamber 10 and an ion lens 9; wherein one end of the capillary 6 extends into the interior of the ionization chamber 10 and is connected to the sample inlet of the ionization chamber 10.

[0027] The capillary 6 is made of high-pressure permeable material, that is, the wall of the capillary 6 is high-pressure permeable material, such as Teflon; a conductive optical fiber 2 is coaxially arranged inside the capillary 6 (the conductive optical fiber 2 is equal to the capillary 6 in length); a filling layer 4 is provided in the annular space between the conductive optical fiber 2 and the inner wall of the capillary 6; the capillary 6 of this structural form can block the air pressure inside and outside the capillary 6 through the high-pressure permeable material (that is, the pressure difference inside and outside the capillary 6 is blocked by the high-pressure permeable material to ensure that there is a lower air pressure in the ionization chamber 10 when the ion source is working; the outside is ultra-high air pressure, and only part of the gas can penetrate into the capillary 6, and the air pressure inside and outside the capillary 6 is different), and the external high-pressure gas penetrates the permeable material to reach the inside of the capillary 6, and passes through the filling layer 4 between the inner wall of the capillary 6 and the conductive optical fiber 2 to reach the ionization chamber 10.

[0028] The filling layer 4 is used to support the conducting optical fiber 2 inside the capillary 6 and increase the air resistance inside the tube; as an example, the filling layer 4 is made of high-purity silica.

[0029] Optical fiber collimator 1 and laser are arranged at the position opposite to the other open end of capillary 6. Fiber collimator 1 is used to adjust the light output angle of laser so that the laser emitted by the laser enters the transmission optical fiber 2 inside capillary 6. By changing the laser light input angle through fiber collimator 1, the optical path is changed to reduce the number of reflections of laser in transmission optical fiber 2. Figure 1 As shown, the laser light emitted by the laser is reflected by the fiber collimator 1 so as to be horizontally incident on the transmission fiber 2 inside the capillary 6. The outer wall of the transmission fiber 2 has a fiber reflection coating 3 to prevent the laser light from scattering out of the fiber and to save the laser energy as much as possible.

[0030] The end of the transmission optical fiber 2 located inside the ionization chamber 10 is provided with a nano silver coating layer 5, and the transmission optical fiber 2 is used to guide the laser to smoothly reach the nano silver coating layer 5. The nano silver coating 5 has good light transmittance and conductivity at the same time. The light transmittance ensures that the laser energy reaches the ionization chamber 10 without damage, and the conductivity ensures its high voltage discharge and ion guiding characteristics. When in use, the positive high voltage electrode 7 provides positive high voltage to the nano silver coating 5.

[0031] A magnet 8 for providing a magnetic field is disposed outside the ionization chamber 10. Under the action of the magnetic field, the ion beam inside the ionization chamber 10 performs a spiral motion in the ionization region, increasing the probability of collision with neutral gas molecules, thereby ensuring ionization efficiency.

[0032] The sample outlet of the ionization chamber 10 is provided with an ion lens 9, which is used for ion focusing, forming an ion flow, excluding neutral particles, and reducing background noise.

[0033] Preferably, the conducting optical fiber 2, the nanosilver coating 5 and the ion focusing hole of the ion lens 9 are coaxial, and the laser, the nanosilver coating 5 with positive high voltage and the ion focusing hole of the ion lens 9 are in the same straight line, which can effectively accelerate the ions and guide the ion flow into an ultra-high vacuum environment.

[0034] The ion source can work stably under an ultra-high gas pressure of 100 MPa. At the same time, the structure can effectively improve the ionization efficiency, thereby providing a higher original signal and improving the detection limit and detection accuracy of the mass spectrometer.

[0035] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A mass spectrometry ion source for ultra-high pressure injection, Features: include: A transmission optical fiber (2), a laser, a capillary (6), an ionization chamber (10) and an ion lens (9); A conducting optical fiber (2) is arranged inside the capillary tube (6), and a filling layer (4) is provided in the annular space between the conducting optical fiber (2) and the inner wall of the capillary tube (6); the tube wall of the capillary tube (6) is a high-pressure permeable material; One end of the capillary (6) extends into the interior of the ionization chamber (10) and is connected to the sample inlet of the ionization chamber (10); a nano silver coating layer (5) is provided at the end of the conductive optical fiber (2) at this end; the nano silver coating layer (5) is provided with a positive high voltage by a positive high voltage electrode (7); The laser is used to emit laser light to the transmission optical fiber (2), and the transmission optical fiber (2) is used to guide the laser light to reach the nano silver coating layer (5); A magnet (8) for providing a magnetic field is arranged outside the ionization chamber (10); and an ion lens (9) is arranged at the sample outlet of the ionization chamber (10).

2. The mass spectrometer ion source for ultra-high pressure injection as claimed in claim 1, Features: It also includes a fiber collimator (1) for adjusting the light output angle of the laser.

3. The mass spectrometer ion source for ultra-high pressure injection as claimed in claim 1, Features: The outer wall of the conducting optical fiber (2) is provided with an optical fiber reflection coating (3).

4. The mass spectrometry ion source for ultra-high pressure injection according to any one of claims 1 to 3, Features: The filling layer (4) is silicon dioxide.

5. The mass spectrometry ion source for ultra-high pressure injection according to any one of claims 1 to 3, Features: The conducting optical fiber (2), the nano silver coating (5) and the ion focusing hole of the ion lens (9) are coaxial.

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