An ion transmission device for mass spectrometry and ion mobility spectrometry instruments

Abstract

The present invention discloses an ion transmission device for mass spectrometry and ion mobility spectrometry instruments; the device comprises an atmospheric sampling component, an ion transmission component and a vacuum chamber; the atmospheric sampling component comprises a conical atmospheric sampling interface, an injection hole is provided at its input end, and a coaxial through hole is provided on its central axis; the ion transmission component comprises an ion transmission capillary and an ion funnel, the ion transmission capillary is embedded in the coaxial through hole via the injection hole, the ion funnel is arranged close to the outlet of the ion transmission capillary, the ion funnel comprises two printed circuit boards fixed to one side of the atmospheric sampling component, the ion funnel is located in the vacuum chamber, one side of the circuit board is a working surface, and the working surfaces of the two circuit boards are arranged in a horizontal mirror image relative to each other; the present invention uses the ion funnel to apply voltage to transmit and focus ions and then transmit them to the front end of the lower chamber, thereby realizing the transmission of ions in various components and various levels of vacuum environment in instruments such as mass spectrometry and ion mobility spectrometry.

Description

Technical Field

[0001] The present invention relates to the technical field of mass spectrometry analysis, and in particular to an ion transmission device for mass spectrometry and ion mobility spectrometry instruments. Background Art

[0002] A mass spectrometer is an advanced, high-end analytical instrument with high sensitivity, strong specificity, and widespread application. Its main structure includes a vacuum system, ion source, ion transmission device, mass analyzer, and signal detection system. It is widely used in many fields such as environment, food, medicine, pharmaceuticals, and life sciences.

[0003] Today, high-performance, large-scale mass spectrometers designed for laboratory environments often use an open, atmospheric, continuous injection method for sample collection. The instrument has at least one injection channel that remains continuously connected to the atmosphere during operation, allowing the ionized sample to be naturally entrained by the airflow and drawn into the instrument due to the pressure difference. This inevitably leads to two problems: First, the rapid pressure decay after the ionized sample enters the instrument causes the air mass to expand rapidly, causing the ions to scatter disorderly within the instrument chamber without guidance, resulting in significant ion loss. Second, a large amount of ambient gas can enter the instrument, contaminating the internal operating environment.

[0004] The most common solution today is to add a first-stage chamber at the front end of the instrument as a buffer to reduce or even prevent the entry of external gases into subsequent chambers. At the same time, an ion funnel is installed within this chamber to constrain and guide the direction of ions and increase ion transmission efficiency. However, conventional ion funnel components are mostly composed of several ring-shaped metal electrodes with openings of decreasing size. This has complex structures, and adjacent electrodes must be arranged in sequence, making installation difficult. There are many components, and disassembly, assembly, and cleaning are time-consuming and labor-intensive. The installation of various parts also results in large cumulative errors. Furthermore, the processing cost is high, and the required chamber space is large. Summary of the Invention

[0005] In response to the aforementioned problems in the prior art, the present invention aims to provide an ion transmission device for use in mass spectrometry and ion mobility spectrometry instruments. The ion transmission device of the present invention features a simple structure, easy assembly and disassembly, low manufacturing cost, ease of maintenance and replacement, and flexible adjustment of the space occupied. The present invention employs an ion funnel module to confine, pull, and separate the ions from other impurities by drawing the ionized sample into a vacuum chamber via an injection module, ultimately achieving efficient and convenient ion transmission. The specific technical solutions of the present invention are described below.

[0006] An ion transmission device for mass spectrometry and ion mobility spectrometry instruments, comprising an atmospheric sampling assembly, an ion transmission assembly, and a vacuum chamber; the atmospheric sampling assembly comprising an atmospheric sampling interface, which is generally conical in shape, with an injection hole formed at its input end and a coaxial through-hole formed on its axis; the ion transmission assembly comprising an ion transmission capillary and an ion funnel, the ion transmission capillary being embedded in the coaxial through-hole via the injection hole, the ion funnel being positioned close to the outlet of the ion transmission capillary, the ion funnel being positioned within the vacuum chamber, the ion funnel comprising two horizontally arranged printed circuit boards, one side of the circuit boards being a component patch soldering surface, the other side being a bare copper working surface, the two printed circuit board working surfaces being mirror images of each other, and the printed circuit boards being fixed to one side of the atmospheric sampling assembly via fixings;

[0007] During operation, the sample to be tested is ionized by an external ion source, sucked into the vacuum chamber through the injection port and transmitted through the ion transfer capillary. The ion funnel with applied voltage pulls and gathers the ions, separates them from the impurities, and transmits them to the front end of the lower chamber, thus realizing a complete ion transmission function from atmosphere to vacuum.

[0008] In the present invention, a front-stage gate electrode, a wall electrode, a radio frequency electrode and a rear-stage gate electrode are respectively provided on the printed circuit board; a DC voltage is applied to the front-stage gate electrode and the rear-stage gate electrode to control the ion passage state of the entire ion funnel; a DC voltage is applied to the wall electrode, and a DC voltage and a radio frequency voltage are applied to the radio frequency electrode, and the DC voltage and the radio frequency voltage jointly form an electric field to form an ion transmission channel; from the front-stage gate electrode to the rear-stage gate electrode, the distance between the wall electrodes on both sides of the radio frequency electrode narrows.

[0009] In the present invention, the ion transmission capillary and the ion funnel axis are parallel and horizontally deviated from each other, so as to prevent the sample airflow from rushing into the lower cavity by inertia.

[0010] In the present invention, the atmospheric sampling interface consists of three parts, namely a conical upper cone, a frustum-shaped lower cone and a cone-shaped lower cone.

[0011] and a cylindrical cone disk, the three parts are fixedly connected in sequence to form an overall cone shape, and coaxial through holes are respectively opened at the center positions of the three parts.

[0012] In the present invention, insulating sheets are provided at the junction of the upper cone and the lower cone, and at the junction of the cone disk and the ion transmission capillary for separation treatment, so that the ion transmission capillary is insulated from other parts of the cavity and voltage can be applied independently to control the transmission of ions and improve the ion pair transmission efficiency.

[0013] In the present invention, a heating and temperature sensing integrated device is provided on the ion transmission capillary of the lower cone and the cone disk opening section to heat and control the temperature of the ion transmission capillary, thereby helping to desolvate the injected ion clusters.

[0014] In the present invention, the printed circuit board is fixed to one side of the atmosphere sampling component through two E-shaped fixing pieces.

[0015] In the present invention, the upper cone and the lower cone are made of aluminum alloy, the cone disk and the ion transmission capillary are made of stainless steel; the insulating sheet is made of polyetheretherketone, and the heating element in the heating and temperature sensing integrated device is made of alumina ceramic.

[0016] In this invention, the rear end of the device is fixed to the walls of the front and rear vacuum chambers via a rear plate and a fixed plate. The invention also includes several sealing O-rings, which are used to seal the connections between the upper cone, lower cone, cone plate, and vacuum chamber to improve the overall vacuum level of the vacuum chamber.

[0017] To address the aforementioned issues with conventional ion funnel systems, such as the large number of parts, complex structure, time-consuming and costly disassembly, cleaning, and maintenance, the present invention has designed an ion transmission device based on printed circuit board technology. This device integrates ion transmission, impurity separation, and focusing guidance, while requiring only two circuit boards and two E-shaped fixtures in the ion transmission module to perform its functions. Compared to existing technologies, the present invention offers the following advantages:

[0018] Compared to traditional ion funnels, the device of the present invention lacks the complex design of stacked metal rings, eliminating the need for numerous components to be installed, removed, and cleaned. The device of the present invention requires minimal space, and the parallel placement of circuit boards significantly reduces the need for vertical space, allowing it to operate in narrow spaces. The device can simultaneously focus and guide ion transmission while simultaneously separating impurities, enabling atmospheric ionization samples to function from sample collection, desolvation, impurity separation, to ion focusing and transmission, thereby cost-effectively improving the performance of instruments such as mass spectrometry and ion mobility spectrometry. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a cross-sectional schematic diagram of an embodiment of the present invention.

[0020] Figure 2 Schematic diagram of the structure of an embodiment of the present invention.

[0021] Figure 3 Schematic diagram of a circuit board according to an embodiment of the present invention.

[0022] The accompanying drawings are:

[0023] 1- ion transmission outlet, 2- rear end plate, 3- insulating fixing part, 4- insulating gasket, 5- sealing O-ring, 6- fixing plate, 7- sealing O-ring, 8- E-shaped fixing part, 9- printed circuit board, 10- cone plate, 11- sealing O-ring, 12- insulating base, 13- limiting hole, 14- sealing O-ring, 15- upper cone, 16- lower cone, 17- insulating plate, 18- sealing O-ring, 19- handle block, 20- handle rod, 21- sealing O-ring, 22- sealing O-ring, 23- ion transmission capillary, 24- heating element, 25- threaded hole, 26- through hole, 27- front stage gate electrode, 28- radio frequency electrode, 29- wall electrode, 30- rear stage gate electrode. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] An ion transmission device for mass spectrometry and ion mobility spectrometry instruments, such as Figure 1-Figure 2 As shown, it comprises an atmospheric sampling assembly, a vacuum ion transport assembly, and an external vacuum chamber. After being ionized by an external ion source, the sample to be tested is drawn through the sampling port and transported into the vacuum chamber via the ion transport capillary 23. An ion funnel is positioned within the chamber, with its entrance adjacent to the exit of the ion transport capillary 23. After the ions leave the ion transport capillary 23 and enter the vacuum chamber, the ion funnel pulls and gathers the ions, separating them from impurities before transporting them to the front end of the lower chamber, thus achieving complete ion transport from atmosphere to vacuum. Specifically, after leaving the ion transport capillary 23 and entering the ion funnel region, a specific voltage is applied to the ion funnel assembly, creating a pseudopotential field between the circuit boards for the ions to pass through. Under the pseudopotential field created by the ion funnel, the ions are constrained by the electric field and gradually gather in the gaps between the ion funnels, moving forward. Furthermore, under the guidance of the ion funnel, the ions' travel direction is inconsistent with the natural flow direction of the gas, allowing the ions to automatically separate from impurities as they travel. Ultimately, the charged particles are guided by the ion funnel into the lower chamber.

[0026] The atmospheric sampling assembly includes an atmospheric sampling interface composed of three parts, a cone-shaped baffle, and a conical baffle. The atmospheric sampling interface is generally conical in shape, with coaxial through-holes on its axis, each of which houses a metal capillary tube 23 embedded therein, serving as an ion transmission capillary. The baffle and ion transmission capillary 23 at the atmospheric sampling interface are insulated, allowing independent voltage application and heating of the ion transmission capillary. The ion funnel portion is composed of two printed circuit boards 9 and two E-shaped fixtures 8. The printed circuit boards 9 have one surface for patching and one surface for working. The working surfaces of the two printed circuit boards 9 are fixed parallel to each other on the E-shaped fixtures 8, creating a gap between the boards that serves as an ion transmission channel. As the spacing between the discharge electrodes on the working surfaces narrows, the ion flow converges and focuses, ultimately forming an ion beam that is transmitted through the small apertures between the cavities to the lower chamber.

[0027] The gas baffle on the atmosphere-facing end consists of three parts: an upper cone 15, a lower cone 16, and a cone disk 10. The upper cone 15 is conical, the lower cone 16 is frustoconical, and the cone disk 10 is cylindrical. They are screwed together in sequence. The upper and lower cones 15, 16 are made of aluminum alloy, while the cone disk 10 is made of stainless steel. An insulating disk 17 separates the upper and lower cones 15, 16. A coaxial through-hole is located at the center of the three parts for the passage of the ion transmission capillary 23. The ion transmission capillary 23 is made of stainless steel. The opening in the upper cone 15 has the same outer diameter as the ion transmission capillary 23, while the inner diameter can be adjusted to suit different experiments and air pressure requirements. The openings in the lower cone 16 and cone disk 10 are larger in size. In a specific embodiment, the opening in the upper cone 15 has a diameter of 2 mm, while the ion transmission capillary 23 has an outer diameter of 2 mm and an inner diameter between 1 mm and 0.4 mm.

[0028] Rubber O-rings of varying sizes seal the connections between the upper cone 15, lower cone 16, cone disk 10, and chamber, preventing air leakage and improving the overall vacuum level of the chamber. Insulating sheets, made of polyetheretherketone, separate the junctions between the upper cone 15 and lower cone 16, and between the cone disk 10 and ion transfer capillary 23. These sheets allow for independent voltage application to the ion transfer capillary 23, improving ion transfer efficiency.

[0029] A heating and temperature-sensing device is mounted on the ion transfer capillary 23 between the lower cone 16 and the opening of the cone disk 10. This device heats and controls the temperature of the ion transfer capillary 23, facilitating the desolvation of sample ion clusters. The heating element 24 of this device is made of alumina ceramic. The temperature control utilizes a thermocouple connected to an external data acquisition device for real-time temperature monitoring and adjustment. The temperature of the ion transfer capillary can be controlled between 24°C and 400°C.

[0030] The ion transmission capillary 23 is horizontally offset from the axis of the ion funnel to prevent the sample flow from rushing into the lower cavity by inertia.

[0031] The vacuum ion funnel assembly includes two printed circuit boards (PCBs) 9 and a PCB fixture. PCBs 9 are primarily made of Rogers sheet metal, with one side being the soldering surface for component SMDs and the other being a bare copper working surface. The working surface is engraved with a bare copper process, with the front-stage gate electrode 27, RF electrode 28, wall electrode 29, and back-stage gate electrode 30 carved into the PCB. The SMD surface is etched with gold, used for soldering various components to form an effective circuit. The two PCBs 9 are mirrored relative to each other, and an E-shaped fixture 8 is used as the PCB fixture to lock and secure the PCBs 9 to one side of the cone 10. The E-shaped fixture 8 has a threaded hole 25 extending through it, and the PCB 9 also has a through-hole 26 of the same size. Align the PCB opening with the E-shaped fixture opening, then use screws to secure them in place. Tighten the nuts on the screws to secure the PCBs completely to the E-shaped fixture. The spacing between the two printed circuit boards 9 is controlled by inserting an E-shaped fixing member 8. The E-shaped fixing member 8 is made of aluminum alloy, and the thickness of the interlayer can be adjusted according to actual needs to control the spacing between the two boards. In a specific embodiment, the spacing between the two printed circuit boards 9 is maintained between 2mm and 3mm.

[0032] The printed circuit board 9 is respectively provided with a front-stage gate electrode, a wall electrode, an RF electrode and a rear-stage gate electrode. A DC voltage V1 is applied to the wall electrode module of the circuit board, and a DC voltage V2 and RF signals RF+ and RF- with the same amplitude and opposite magnitude are applied to the RF electrode module to realize the ion transmission function. DC voltages V4 and V5 are applied to the front-stage gate electrode and the rear-stage gate electrode modules of the circuit board to control the ion passage state of the entire ion funnel, which is used to adjust the connection / disconnection state of the ion transmission path and avoid charge accumulation.

[0033] In the present invention, a limiting hole device is provided before connecting to the lower chamber. The limiting hole device is a metal baffle with a 2mm hole facing the outlet of the ion funnel for ions to pass through. The limiting hole device is also used to reduce the gas exchange volume between the ion transmission chamber and the rear chamber, so as to maintain the pressure difference between the chambers. Example 1

[0034] In an embodiment, an ion transmission device for a mass spectrometer or an ion mobility spectrometer is provided, such as Figure 1-Figure 2 As shown, it includes an atmospheric sampling device and a vacuum ion transmission device. The present invention utilizes a pressure difference to draw sample ionized by an atmospheric pressure source into the device. The sample is then transported through an ion funnel to separate the ionized sample from impurities and to gather and transport the ions to the next chamber. This invention is an ion transmission device that can be used in environments ranging from atmospheric pressure to vacuum.

[0035] Specifically, when in use, the device is mounted on the instrument's fore-stage vacuum chamber. The conical disk 10 isolates the atmosphere from the chamber's vacuum environment, while the rear disk 2 and fixed disk 6 secure the device's rear end to the walls of the fore-stage and rear-stage vacuum chambers. Sealing O-rings 5, 7, 11, 14, 18, 21, and 22 seal gaps created during assembly to reduce leakage under high pressure differentials. Ions are drawn into the chamber via a stainless steel ion transfer capillary 23, which is capped with an alumina ceramic heater 24 to increase the temperature and promote desolvation of the sample. After entering the chamber from the atmosphere, the ions enter the ion mobility region formed by the printed circuit board 9. Here, the ionized sample is concentrated and transported by the ion funnel formed by the printed circuit board 9, where it is separated from any entrained gases. Finally, the ions pass through the stopper hole 13 and enter the lower chamber. Mounted on the cone 10 are removable handle blocks 19 and handle bars 20, which serve as auxiliary mounting handles for easy access during assembly and disassembly of the device. Once the device is inserted into the cavity, both handle blocks 19 and handle bars 20 can be removed from the cone 10 without affecting normal operation.

[0036] As mentioned above, the device of the present invention is mainly used in instruments such as mass spectrometry and ion mobility spectrometry to realize the transmission of ions in various groups of components and various levels of vacuum environment to form a complete ion transmission link. It uses a metal capillary injection channel and natural air pressure difference to realize ion transmission from normal pressure to reduced pressure vacuum environment. At the same time, there is a certain offset between the atmospheric end injection port and the secondary ion transmission outlet 1, that is, the ion funnel axis outlet, the purpose of which is to block the impurities that enter the cavity together with the ions, so that as little as possible enters the lower cavity to prevent affecting the purity of the subsequent chamber gas; in a vacuum environment, the ion funnel designed and manufactured based on printed circuit board technology is used to carry out direction-guided transmission of ions; based on the radio frequency electric field pseudopotential effect, applying a certain radio frequency signal and a direct current signal to the two-circuit board ion funnel assembly can effectively control the directional movement of charged particles, thereby realizing the direction-guided transmission of ions.

[0037] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. An ion transmission device for mass spectrometry and ion mobility spectrometry instruments, characterized in that: The invention comprises an atmospheric sampling component, an ion transmission component and a vacuum chamber; the atmospheric sampling component comprises an atmospheric sampling interface, which is generally conical in shape, with an injection hole provided at its input end and a coaxial through hole provided on its axis; the ion transmission component comprises an ion transmission capillary and an ion funnel, the ion transmission capillary is embedded in the coaxial through hole via the injection hole, the ion funnel is arranged close to the outlet of the ion transmission capillary, the ion funnel is located in the vacuum chamber, and the ion funnel comprises two horizontally arranged printed circuit boards, one side of the circuit board is a component patch welding surface, and the other side is a bare copper working surface, the working surfaces of the two printed circuit boards are arranged in mirror images relative to each other, and the printed circuit board is fixed to one side of the atmospheric sampling component by a fixing piece; During operation, the sample to be tested is ionized by an external ion source, sucked into the vacuum chamber through the injection port and transmitted through the ion transfer capillary. The ion funnel with applied voltage pulls and gathers the ions, separates them from the impurities, and transmits them to the front end of the lower chamber, thus realizing a complete ion transmission function from atmosphere to vacuum.

2. The ion transmission device for mass spectrometry and ion mobility spectrometry instruments according to claim 1, characterized in that: The printed circuit board is respectively provided with a front-stage gate electrode, a wall electrode, a radio frequency electrode and a back-stage gate electrode; a DC voltage is applied to the front-stage gate electrode and the back-stage gate electrode to control the ion passage state of the entire ion funnel; a DC voltage is applied to the wall electrode, and a DC voltage and a radio frequency voltage are applied to the radio frequency electrode. The DC voltage and the radio frequency voltage together form an electric field to form an ion transmission channel; from the front-stage gate electrode to the back-stage gate electrode, the distance between the wall electrodes on both sides of the radio frequency electrode narrows.

3. The ion transmission device for mass spectrometry and ion mobility spectrometry instruments according to claim 1, characterized in that: The ion transfer capillary is horizontally offset from the axis of the ion funnel to prevent the inlet gas flow from rushing into the lower cavity by inertia.

4. The ion transmission device for mass spectrometry and ion mobility spectrometry instruments according to claim 1, characterized in that: The atmospheric sampling interface consists of three parts, namely a conical upper cone, a frustum-shaped lower cone and a cylindrical cone disk. The three parts are fixedly connected in sequence to form an overall cone shape, and coaxial through holes are respectively opened in the center positions of the three parts.

5. The ion transmission device for mass spectrometry and ion mobility spectrometry instruments according to claim 4, characterized in that: Insulating sheets are provided at the junction of the upper cone and the lower cone, and at the junction of the cone disk and the ion transmission capillary for separation, so that the ion transmission capillary can independently apply voltage to achieve control of ion transmission.

6. The ion transmission device for mass spectrometry and ion mobility spectrometry instruments according to claim 4, characterized in that: A heating and temperature sensing integrated device is provided on the ion transmission capillary of the lower cone and the opening section of the cone disk to heat and control the temperature of the ion transmission capillary to help desolvate the injected ion clusters.

7. The ion transmission device for mass spectrometry and ion mobility spectrometry instruments according to claim 1, characterized in that: The printed circuit board is fixed to one side of the atmosphere sampling assembly through two E-type fixing pieces.

8. The ion transmission device for mass spectrometry or ion mobility spectrometry according to any one of claims 1 to 7, characterized in that: The upper cone and the lower cone are made of aluminum alloy, the cone disk and the ion transmission capillary are made of stainless steel; the insulating sheet is made of polyetheretherketone, and the heating element in the heating and temperature sensing integrated device is made of alumina ceramic.

9. The ion transmission device for mass spectrometry and ion mobility spectrometry instruments according to claim 1, characterized in that: The rear end of the device is fixed to the front-stage vacuum chamber and the rear-stage vacuum chamber wall through a rear-end plate and a fixing plate.

10. The ion transmission device for mass spectrometry and ion mobility spectrometry instruments according to claim 1, characterized in that: It also includes several sealing O-rings, which are used to seal the joints between the upper cone, the lower cone, the cone disk and the vacuum chamber to improve the overall vacuum degree of the vacuum chamber.

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