Secondary electrospray ionization source based on 3D printing and processing method

Abstract

The invention provides a secondary electrospray ion source based on 3D printing and a processing method thereof, and relates to the technical field of mass spectrum ion sources, the secondary electrospray ion source comprises a sample introduction device, an electrospray device, a gas circuit module and a mass spectrometer; the sampling device comprises a plurality of aerodynamic lenses with different apertures; the electrospray device comprises a conductive wire and a high-voltage static electricity supply device, and the other end of the conductive wire is led into the electrospray bottle; the air path module comprises an air pressure supply device and an electric spray needle, an air outlet of the air pressure supply device is communicated into the electric spray bottle, the electric spray needle comprises a spray needle and an inlet end, and the inlet end is communicated into the extraction liquid of the electric spray bottle; the outlet end of the sample introduction device, the sample introduction end of the mass spectrometer and the spray needle are located in the ionization chamber, the outlet end of the sample introduction device and the sample introduction end of the mass spectrometer are located on the same straight line, and the spray needle is located between the outlet end of the sample introduction device and the sample introduction end of the mass spectrometer. The invention has the advantages of small volume, low price and simplicity in processing.

Description

Technical Field

[0001] The present invention relates to the technical field of mass spectrometry ion sources, and particularly to a processing method for a secondary electrospray ion source based on 3D printing. Background Art

[0002] Secondary Electro-Spray Ionization (SESI) is a new ionization technique developed from Electro-Spray Ionization (ESI). Its principle is to introduce a sample into an injection channel and collide with electrospray droplets for secondary ionization. It mainly includes two core components, an injection channel assembly and an electrospray assembly. The injection channel is filled with the sample to be measured, and the electrospray assembly is filled with an energized solution without the analyte to form primary electrospray ions; the two meet in the ionization chamber, undergo extraction ionization, and then enter the mass spectrometer.

[0003] Existing secondary electrospray ionization sources are large in volume and expensive in cost, and their processing process is time-consuming and laborious. Summary of the Invention

[0004] The present invention aims to provide a secondary electrospray ion source based on 3D printing and its processing method, so as to at least partially solve at least one of the above technical problems.

[0005] To solve the above technical problems, the first aspect of the present invention provides a secondary electrospray ionization source based on 3D printing, including: an injection device, an electrospray device, a gas path module, and a mass spectrometer;

[0006] The injection device includes: a plurality of aerodynamic lenses with different apertures, which can focus aerosol or gas into an air flow of a predetermined size;

[0007] The electrospray device includes: a conductive wire, a high-voltage electrostatic providing device connected to one end of the conductive wire, and the other end of the conductive wire is inserted into an electrospray bottle filled with an extraction solution;

[0008] The gas path module includes: a gas pressure providing device and an electrospray needle. The air outlet of the gas pressure providing device is inserted into the electrospray bottle. The electrospray needle includes: a needle and an inlet end, and the inlet end is inserted into the extraction solution in the electrospray bottle;

[0009] The outlet end of the injection device, the inlet end of the mass spectrometer, and the needle are located in the ionization chamber. The outlet end of the injection device and the inlet end of the mass spectrometer are on the same straight line, and the needle is located between the outlet end of the injection device and the inlet end of the mass spectrometer.

[0010] According to a preferred embodiment of the present invention, the sample introduction device further includes: an air cavity, the aerodynamic lens is a round hole provided in the air cavity and parallel to the air cavity inlet, and there are three of them, and the aperture diameters of the three round holes decrease in sequence along the air cavity inlet direction.

[0011] According to a preferred embodiment of the present invention, along the air cavity inlet direction, the inner diameters of the three round holes are respectively: 1.5 mm - 1.0 mm - 0.8 mm.

[0012] According to a preferred embodiment of the present invention, the gas path module further includes: a pressure regulating valve provided between the air pressure providing device and the electrospray bottle; and a pressure detecting device connected to the inlet end of the electrospray needle.

[0013] According to a preferred embodiment of the present invention, the conductive wire is a tantalum wire, and the high-voltage electrostatic providing device is connected to the tantalum wire through a metal wire.

[0014] According to a preferred embodiment of the present invention, the electrospray needle further includes: a needle cavity, the needle cavity includes a plurality of annular pipes, the pipe sizes from the middle to both ends of the needle cavity gradually decrease, both ends of the needle cavity are respectively connected to the spray needle and the inlet end, and the size of the spray needle gradually decreases and is the smallest at the outlet.

[0015] To solve the above technical problems, the second aspect of the present invention provides a method for processing a secondary electrospray ionization source based on 3D printing, including:

[0016] Using stereolithography 3D printing technology to integrally form an aerodynamic lens, an ionization chamber, and an electrospray needle interface, and passivate their surfaces;

[0017] Using micro-nano 3D printing technology to print the spray needle;

[0018] Combining the sample introduction device, the electrospray device, the gas path module and the mass spectrometer, wherein:

[0019] The sample introduction device includes: a plurality of aerodynamic lenses, which can focus the aerosol or gas into an air flow of a predetermined size;

[0020] The electrospray device includes: a conductive wire, a high-voltage electrostatic providing device connected to one end of the conductive wire, the other end of the conductive wire is led into the electrospray bottle, and the electrospray bottle is filled with an extraction solution;

[0021] The gas path module includes: an air pressure providing device and an electrospray needle, the air outlet of the air pressure providing device is led into the electrospray bottle, the electrospray needle includes: a spray needle and an inlet end, and the inlet end is led into the extraction solution in the electrospray bottle;

[0022] The outlet end of the sample introduction device, the inlet end of the mass spectrometer, and the injection needle are located inside the ionization chamber. The outlet end of the sample introduction device and the inlet end of the mass spectrometer are on the same straight line, and the injection needle is located between the outlet end of the sample introduction device and the inlet end of the mass spectrometer.

[0023] According to a preferred embodiment of the present invention, before integrally forming the aerodynamic lens by using the photocuring 3D printing technology, the method further includes:

[0024] Designing the assembly design of the secondary electrospray ion source;

[0025] According to the assembly design, using the fused deposition 3D printing technology, manufacturing the housing of the secondary electrospray ion source with ABS and PLA materials.

[0026] According to a preferred embodiment of the present invention, the passivation treatment includes: surface activation bond energy and / or silicon oxidation.

[0027] According to a preferred embodiment of the present invention, the inner diameter of the injection needle is 5 - 100 microns; the injection needle with an inner diameter of 5 - 10 microns is processed by using the two-photon 3D printing technology, and the injection needle with an inner diameter of 10 - 100 microns is printed by using the photocuring 3D printing technology.

[0028] In summary, the secondary electrospray ion source based on 3D printing provided by the present invention connects a conductive wire through a high-voltage electrostatic providing device into the spray bottle to provide an adjustable high voltage, making the extractant in the electrospray bottle charged. The air pressure providing device provides a stable air pressure to the electrospray bottle, so that the extraction liquid in the electrospray bottle stably flows out from the electrospray injection needle, and a Taylor cone electrospray is formed at the tip of the injection needle; by designing a plurality of aerodynamic lenses with different apertures to focus the aerosol or gas into an air flow of a predetermined size, collide with the charged spray ejected from the electrospray injection needle, and undergo extraction ionization, thereby entering the mass spectrometer to generate a signal. The processing method of the secondary electrospray ion source based on 3D printing provided by the invention designs and prints the aerodynamic lens, ionization chamber, electrospray injection needle interface, and injection needle of the above-mentioned secondary electrospray ion source based on 3D printing technology. Compared with the mechanical processing of the secondary electrospray ion source, the coaxiality between the aerodynamic lenses is better, making the volume of the secondary electrospray ion source smaller, the airtightness better, and at the same time greatly reducing the production cost, and having a wide range of application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of a secondary electrospray ionization source based on 3D printing provided by Embodiment 1 of the present invention;

[0030] Figures 2a - 2dSchematic diagram of the connection of the sample injection device, the spray needle, and the mass spectrometer in the secondary electrospray ionization source based on 3D printing provided in the first embodiment of the present invention;

[0031] Figure 3 Test diagram of the focusing effect of the sample injection device provided in the first embodiment of the present invention;

[0032] Figure 4 Aerodynamic simulation diagram of the sample injection device provided in the first embodiment of the present invention;

[0033] Figure 5 Simulation diagram of the Taylor cone jet model formed at the spray needle provided in the first embodiment of the present invention;

[0034] Wherein: 1 - sample injection device, 2 - electrospray needle, 3 - sample injection end of the mass spectrometer, 4 - air pressure providing device, 5 - pressure regulating valve, 6 - electrospray bottle, 7 - high - voltage electrostatic providing device, 8 - pressure detection device, 9 - conductive wire, 10 - ionization chamber, 11 - aerodynamic lens, 12 - electrospray needle interface. Detailed implementation manners

[0035] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. For the purpose of making the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be implemented without some of these specific details. The following description of the embodiments is only intended to provide a better understanding of the present invention by showing examples of the present invention.

[0036] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non - exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, the elements defined by the statement "including..." do not exclude the existence of additional identical elements in the process, method, article or device including the said elements.

[0037] Embodiment 1

[0038] The first embodiment of the present invention provides a secondary electrospray ion source based on 3D printing, as Figure 1As shown, the 3D printing-based secondary electrospray ionization source includes: a sample injection device 1, an electrospray device, a gas path module, and a mass spectrometer; wherein:

[0039] The sample injection device 1 includes: a gas chamber, in which there are a plurality of aerodynamic lenses 11 with different apertures. The aerodynamic lenses 11 can focus the aerosol or gas sample entering the gas chamber into an air flow of a predetermined size. Preferably, the aerodynamic lenses 11 are circular holes provided in the gas chamber and parallel to the gas chamber inlet, and there are three of them. The apertures of the three circular holes decrease in sequence along the gas chamber inlet direction; in this way, the gas or aerosol rapidly expands through the first circular hole into the gas chamber, then enters the second smaller circular hole and contracts, rapidly expands into the gas chamber again, and then enters the third smaller circular hole and contracts, so that the air flow is continuously focused to form a linear air flow of a predetermined size. As Figure 3 and 4 shown, through ansys fluent for aerodynamic simulation, along the gas chamber inlet direction, the lens combination with the inner diameters of the three circular holes being 1.5mm - 1.0mm - 0.8mm has the best focusing effect.

[0040] The electrospray device includes: a conductive wire 9, a high-voltage electrostatic providing device 7 connected to one end of the conductive wire 9, and the other end of the conductive wire 9 extends into an electrospray bottle 6 which is filled with an extraction solution. Among them: the high-voltage electrostatic providing device 7 can adopt the AL730207091 general-purpose electrostatic generating connection system to provide an adjustable high-voltage output of 0 - 30 kV. The conductive wire 9 can be a metal wire, preferably a tantalum wire, with a wire diameter of 0.25 mm. Two are wound and extend into the extraction solution, and are connected to the high-voltage electrostatic providing device 7 through a metal wire above. The extraction solution is preferably a methanol-water extraction solution.

[0041] The gas path module includes: a gas pressure providing device 4 and an electrospray needle 2. The air outlet of the gas pressure providing device 4 leads into the electrospray bottle 6. The electrospray needle 2 includes: a needle and an inlet end, and the inlet end leads into the extraction solution in the electrospray bottle. By the gas pressure providing device 4 providing a stable gas pressure to the electrospray bottle 6, the extraction solution in the electrospray bottle 6 stably flows out from the electrospray needle 2 and forms a Taylor cone electrospray at the tip of the needle. Figure 5It is a simulation diagram of the Taylor cone jet formed at the injection needle. Preferably, a pressure regulating valve 5 can also be provided between the air pressure providing device 4 and the electrospray bottle 6; and a pressure detection device 8 is connected to the inlet end of the electrospray needle 2. Thus, air pressure is provided by the air pressure providing device 4, the air pressure is controlled by the pressure regulating valve 5, and the air pressure value is displayed in the air pressure detection device 8, and then introduced into the electrospray bottle 6, so that the flow rate of the gas or aerosol in the electrospray needle 2 is controlled at a flow rate of 1 μL / min. Further, the electrospray needle 2 further includes: a needle cavity, the needle cavity includes a plurality of annular pipes, the pipe size from the middle to both ends of the needle cavity gradually decreases, both ends of the needle cavity are respectively connected to the injection needle and the inlet end, and the size of the injection needle gradually decreases and is the smallest at the outlet. The injection needle is processed by micro-nano 3D printing technology, and its structure is a tapered pipe with a gradually narrowing outlet. The inner diameter of the outlet is controlled within 1-50 μm. During the processing, through COMSOL Multiphysics simulation, the different flow rates corresponding to different inner diameters of the injection needle and the corresponding voltage range can be calculated to control the voltage provided by the voltage providing device. Among them: the air pressure providing device 4 can adopt a gas cylinder, an air pump, etc. The air pressure detection device 8 can adopt a pressure sensor, a precision pressure gauge, etc.

[0042] In this embodiment, the outlet end of the sampling device 1, the sampling end 3 of the mass spectrometer, and the injection needle are located in the ionization chamber 10. The outlet end of the sampling device 1 and the sampling end 3 of the mass spectrometer are on the same straight line, and the injection needle is located between the outlet end of the sampling device 1 and the sampling end 3 of the mass spectrometer. In this way, the airflow focused by the sampling device 1 collides with the charged spray ejected from the electrospray needle 2 in the ionization chamber, and extraction ionization occurs, thereby entering the mass spectrometer to generate a signal. Specifically, referring to Figures 2a - 2d , the aerodynamic lens 11 at the outlet end of the sampling device 1 is horizontally connected to one end of the ionization chamber 10, and an electrospray needle interface 12 is provided above the ionization chamber 10. The injection needle is connected to the ionization chamber 10 through the electrospray needle interface 12. A base is provided at the other end of the ionization chamber 10 and is connected to the mass spectrometer by threading the base.

[0043] Embodiment 2

[0044] Embodiment 2 of the present invention provides a method for processing a secondary electrospray ionization source based on 3D printing, and the method includes:

[0045] S1. Integrally form an aerodynamic lens, an ionization chamber, and an electrospray needle interface by using stereolithography 3D printing technology, and passivate their surfaces;

[0046] Preferably, before this step, the assembly design of the secondary electrospray ion source can also be carried out through 3D modeling software, such as Solidworks. According to the assembly design, using the fused deposition 3D printing technology, the housing of the secondary electrospray ion source is manufactured with ABS and PLA materials. Among them: the assembly design can include: the design of the shape and / or size of the sample introduction device, the electrospray device, the gas path module, the ionization chamber, and the housing, so that the housing can not only protect the internal sample introduction device, electrospray device, and gas path module, but also be adapted to the sample introduction interface of the mass spectrometer. Preferably, in the embodiment of the present invention, the sample introduction device is integrally designed by 3D modeling software to obtain a structure such as Figures 2a - 2d , which retains the maximum functional units, removes the redundant parts, realizes miniaturization, thereby saving materials and printing time, and reducing the manufacturing cost.

[0047] After the aerodynamic lens, ionization chamber, and electrospray needle interface are integrally formed by the stereolithography 3D printing technology, due to the volatiles in the printed parts, the background signal value is too high during the sample introduction of the mass spectrometer. Therefore, surface passivation treatment is carried out. The passivation treatment can include steps such as surface activation bond energy and silicon oxidation. For the treated parts, the volatiles are inhibited, meeting the requirements of the mass spectrometer for on-machine testing.

[0048] In this embodiment, for the aerodynamic lens using the stereolithography 3D printing technology, the aerodynamic simulation is carried out through the fluid simulation software ansysfluent, and it is determined that the focusing effect of the lens combination of 1.5mm - 1.0mm - 0.8mm is the best.

[0049] S2. Print the needle using the micro-nano 3D printing technology;

[0050] In this embodiment, the needle adopts a tapered pipe design, with a total channel length of 10mm, a wall thickness of 5 microns at the needle tip, and an inner diameter set to 5 - 100 microns. The needle with an inner diameter of 5 - 10 microns is processed by the two-photon 3D printing technology, and the needle with an inner diameter of 10 - 100 microns is printed by the stereolithography 3D printing technology. The flow rate ranges of needles with different inner diameters are also different when forming the Taylor cone jet. Needles with different inner diameters can be selected according to the requirements of different detection application scenarios.

[0051] S3. Combine the sample introduction device 1, the electrospray device, the gas path module, and the mass spectrometer, where:

[0052] The sample introduction device 1 includes: a plurality of aerodynamic lenses, which can focus the aerosol or gas into an air flow of a predetermined size;

[0053] The electrospray device includes: a conductive wire 9, a high-voltage electrostatic providing device connected to one end of the conductive wire 9, and the other end of the conductive wire 9 is led into the electrospray bottle 6, and the electrospray bottle 6 is filled with an extraction solution;

[0054] The gas path module includes: a gas pressure providing device 4 and an electrospray needle 2. The gas outlet of the gas pressure providing device 4 leads into the electrospray bottle 6. The electrospray needle 2 includes a needle and an inlet end, and the inlet end leads into the extraction solution in the electrospray bottle 6;

[0055] The outlet end of the sample injection device 1 and the sample injection end 3 of the mass spectrometer are located on the same straight line, and the needle is located between the outlet end of the sample injection device 1 and the sample injection end 3 of the mass spectrometer.

[0056] It should be clear that the present invention is not limited to the specific structures and processes described above and shown in the figures. For the sake of brevity, the detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order between steps after understanding the spirit of the present invention.

[0057] It should also be noted that the exemplary embodiments mentioned in the present invention describe some methods or systems based on a series of steps or devices. However, the present invention is not limited to the order of the above steps. That is, the steps can be executed in the order mentioned in the embodiments, or different from the order in the embodiments, or several steps can be executed simultaneously.

[0058] As described above, only the specific embodiments of the present invention are provided. Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the above-described systems, modules, and units can refer to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A secondary electrospray ionization source based on 3D printing, characterized in that, Comprising: A sample introduction device, an electrospray device, a gas path module, and a mass spectrometer; The sample introduction device includes: a plurality of aerodynamic lenses with different apertures, which can focus aerosol or gas into an air flow of a predetermined size; The electrospray device includes: a conductive wire, a high-voltage electrostatic providing device connected to one end of the conductive wire, and the other end of the conductive wire is inserted into an electrospray bottle filled with an extraction solution; The gas path module includes: a gas pressure providing device and an electrospray needle. The air outlet of the gas pressure providing device is inserted into the electrospray bottle. The electrospray needle includes: a needle and an inlet end, and the inlet end is inserted into the extraction solution in the electrospray bottle; The outlet end of the sample introduction device, the inlet end of the mass spectrometer, and the needle are located in the ionization chamber. The outlet end of the sample introduction device and the inlet end of the mass spectrometer are on the same straight line, and the needle is located between the outlet end of the sample introduction device and the inlet end of the mass spectrometer.

2. The secondary electrospray ionization source based on 3D printing according to claim 1, wherein The sample introduction device further includes: a gas chamber. The aerodynamic lens is a round hole parallel to the gas chamber inlet and is provided in the gas chamber, and there are three of them. The apertures of the three round holes gradually decrease along the gas chamber inlet direction.

3. The secondary electrospray ionization source based on 3D printing according to claim 1, characterized in that, Along the gas chamber inlet direction, the inner diameters of the three round holes are respectively: 1.5 mm - 1.0 mm - 0.8 mm.

4. The secondary electrospray ionization source based on 3D printing according to claim 1, characterized in that, The gas path module further includes: a pressure regulating valve provided between the gas pressure providing device and the electrospray bottle; and a pressure detection device connected to the inlet end of the electrospray needle.

5. The secondary electrospray ionization source based on 3D printing according to claim 1, characterized in that, The conductive wire is a tantalum wire, and the high-voltage electrostatic providing device is connected to the tantalum wire through a metal wire.

6. The secondary electrospray ionization source based on 3D printing according to claim 2, wherein The electrospray needle further includes: a needle chamber. The needle chamber includes a plurality of annular pipes, and the pipe sizes gradually decrease from the middle to both ends of the needle chamber. The two ends of the needle chamber are respectively connected to the needle and the inlet end, and the size of the needle gradually decreases and is the smallest at the outlet.

7. A processing method for a secondary electrospray ionization source based on 3D printing, characterized in that, Comprising: The manufacturing process uses photocuring 3D printing technology to integrally form and process the aerodynamic lens; The ionization chamber and the electrospray needle interface are passivated on their surfaces; The needle is printed using micro-nano 3D printing technology; The sample introduction device, the electrospray device, the gas path module, and the mass spectrometer are combined, where: The sample introduction device includes: a plurality of aerodynamic lenses, which can focus aerosol or gas into an air flow of a predetermined size; The electrospray device includes: a conductive wire, a high-voltage electrostatic providing device connected to one end of the conductive wire, and the other end of the conductive wire is inserted into an electrospray bottle filled with an extraction solution; The gas path module includes: a gas pressure providing device and an electrospray needle. The air outlet of the gas pressure providing device is inserted into the electrospray bottle. The electrospray needle includes: a needle and an inlet end, and the inlet end is inserted into the extraction solution in the electrospray bottle; The outlet end of the sample introduction device, the inlet end of the mass spectrometer, and the needle are located in the ionization chamber. The outlet end of the sample introduction device and the inlet end of the mass spectrometer are on the same straight line, and the needle is located between the outlet end of the sample introduction device and the inlet end of the mass spectrometer.

8. A method for processing a secondary electrospray ionization source based on 3D printing according to claim 7, characterized in that, Before integrally forming the aerodynamic lens using photocuring 3D printing technology, the method further includes: Designing the assembly design of the secondary electrospray ion source; According to the assembly design, the outer shell of the secondary electrospray ion source is manufactured using fused deposition 3D printing technology with ABS and PLA materials.

9. A method for processing a secondary electrospray ionization source based on 3D printing according to claim 7, wherein, The passivation treatment includes: surface activation bond energy and / or silicon oxidation.

10. A method for processing a secondary electrospray ionization source based on 3D printing according to claim 7, characterized in that, The inner diameter of the needle is 5 - 100 microns; a needle with an inner diameter of 5 - 10 microns is processed using two-photon 3D printing technology, and a needle with an inner diameter of 10 - 100 microns is printed using stereolithography 3D printing technology.

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