Ion transmission device for mass spectrum and ion mobility spectrometry instrument

Abstract

The invention discloses an ion transmission device for a mass spectrum and ion mobility spectrometry instrument. The device comprises an atmosphere sample introduction assembly, an ion transmission assembly and a vacuum cavity, the atmosphere sample introduction assembly comprises a conical atmosphere sample introduction interface, a sample introduction hole is formed in the input end of the atmosphere sample introduction interface, and a coaxial through hole is formed in the central axis; the ion transmission assembly comprises an ion transmission capillary tube and an ion funnel, the ion transmission capillary tube is embedded in the coaxial through hole through the sample introduction hole, the ion funnel is arranged close to the outlet position of the ion transmission capillary tube, and the ion funnel comprises two printed circuit boards fixed on one side of the atmosphere sample introduction assembly and located in the vacuum cavity; one surface of each circuit board is a working surface, and the working surfaces of the two circuit boards are arranged oppositely and horizontally; according to the invention, ions are transmitted and focused by the ion funnel for applying voltage and then are transmitted to the front end of the lower-stage cavity, so that the transmission of the ions in each group of parts and each stage of vacuum environment in instruments such as a mass spectrum and an ion mobility spectrum is realized.

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] Mass spectrometer is an advanced high-end analytical instrument with high sensitivity, strong specificity and wide application. Its main structure includes vacuum system, ion source, ion transmission device, mass analyzer and signal detection system, etc. It is widely used in many fields such as environment, food, medical treatment, medicine, life science, etc.

[0003] Nowadays, high-performance large-scale mass spectrometers for laboratory environments mostly use an open atmospheric pressure continuous injection method for sample collection, and the instrument has at least one injection channel that is continuously connected to the atmosphere during operation, so that the ionized sample is naturally sucked into the instrument by the airflow under the action of the pressure difference. This will inevitably bring two problems: First, after the ionized sample enters, the rapid pressure decay will cause the air mass to expand rapidly, which will cause the ions to scatter disorderly in the instrument cavity without guidance, resulting in a large number of ion losses. Second, a large amount of environmental gas will enter the instrument, which will pollute the internal operating environment of the instrument.

[0004] The most commonly used solution nowadays is to add a first-level cavity as a buffer at the front end of the instrument to reduce or even prevent external gas from entering the subsequent chamber, and at the same time install an ion funnel in the cavity to constrain and guide the direction of ion travel to increase ion transmission efficiency. However, conventional ion funnel components are mostly composed of several ring-shaped metal electrode sheets with regularly decreasing opening sizes. They have complex structures, and adjacent electrode sheets must be arranged in sequence, which is difficult to install. There are many components, and the disassembly, assembly, and cleaning process is time-consuming and labor-intensive. The cumulative installation errors of various parts are large; the processing cost is high; and the required cavity space is large. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the purpose of the present invention is to propose an ion transmission device for mass spectrometry and ion mobility spectrometry instruments. The ion transmission device of the present invention has a simple structure, is easy to disassemble and assemble, has a low manufacturing cost, is easy to maintain and replace, and the size of the occupied space can be flexibly adjusted. The present invention is an instrument that uses an ion funnel module to confine, pull, and separate the ions from the remaining impurities after the ionized sample is sucked into the vacuum chamber through the injection module, and finally realizes efficient and convenient ion transmission. The specific technical solution of the present invention is introduced as follows.

[0006] An ion transmission device for mass spectrometry and ion mobility spectrometry instruments, comprising an atmospheric sampling component, an ion transmission component and a vacuum chamber; the atmospheric sampling component comprises an atmospheric sampling interface, which is in a cone shape as a whole, and an injection hole is provided at its input end, and a coaxial through hole is 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 position of the ion transmission capillary, the ion funnel is located in the vacuum chamber, 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 two printed circuit board working surfaces are arranged in mirror images relative to each other, and the printed circuit board is fixed to one side of the atmospheric sampling component through a fixing piece; During operation, after the sample to be tested is ionized by an external ion source, it is sucked into the vacuum chamber through the injection hole and transmitted through the ion transmission capillary. The ions are pulled, gathered, separated from the impurities by the ion funnel with applied voltage and then transmitted to the front end of the lower chamber, thus realizing a complete ion transmission function from atmosphere to vacuum.

[0007] In the present invention, a front-stage gate electrode, a wall electrode, a radio frequency electrode and a rear-stage gate electrode are respectively arranged 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 passing 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.

[0008] In the present invention, the ion transmission capillary is horizontally offset from the axis of the ion funnel to prevent the sample airflow from rushing into the lower cavity by inertia.

[0009] In the present invention, the atmospheric sampling interface is composed of three parts, namely a conical upper cone, a truncated cone lower cone, and a and a cylindrical cone disk, the three parts are fixedly connected in sequence to form an integral cone shape, and coaxial through holes are respectively opened at the center positions of the three parts.

[0010] 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 transmission efficiency of ion pairs.

[0011] In the present invention, 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 and help desolvation of the injected ion clusters.

[0012] In the present invention, the printed circuit board is fixed on one side of the atmosphere injection assembly through two E-shaped fixing pieces.

[0013] 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.

[0014] In the present invention, the rear end of the device is fixed to the front stage vacuum chamber and the rear stage vacuum chamber wall through the rear end plate and the fixed plate. In the present invention, several sealing O-rings are also included, which are used to seal the upper cone, the lower cone, the cone plate and the vacuum chamber parts to improve the overall vacuum degree of the vacuum chamber.

[0015] Based on the above problems, such as the large number of parts, complex structure, time-consuming and high-cost disassembly, cleaning and maintenance of conventional ion funnel systems, the present invention designs an ion transmission device based on printed circuit board technology. This device integrates the functions of ion transmission, impurity separation, focusing and guidance, and only two circuit boards and two E-shaped fixings are needed in the ion transmission module to complete the functions. Compared with the prior art, the beneficial effects of the present invention are: Compared with the traditional ion funnel device, the device of the present invention does not have a complex stacked metal ring design, eliminating the need for installation, removal and cleaning of a large number of components. The device of the present invention has a small space requirement, and the parallel placement of the circuit boards can greatly reduce the demand for longitudinal space, and can be placed in a narrow space for work; the device can achieve impurity separation while gathering and guiding ion transmission, and realize the functions of atmospheric ionization samples from sample collection, desolvation, impurity separation to ion gathering and transmission, thereby improving the instrument performance of instruments such as mass spectrometry and ion mobility spectrometry at low cost and difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional schematic diagram of an embodiment of the present invention.

[0017] Figure 2 It is a schematic structural diagram of an embodiment of the present invention.

[0018] Figure 3 Schematic diagram of a circuit board according to an embodiment of the present invention.

[0019] The accompanying drawings are marked as follows: 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-conical 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-RF electrode, 29-wall electrode, 30-rear-stage gate electrode. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0021] An ion transmission device for mass spectrometry and ion mobility spectrometry instruments, such as Figure 1-Figure 2 As shown, it includes an atmospheric sampling component, a vacuum ion transmission component and an external vacuum chamber; after the sample to be tested is ionized by the external ion source, it is sucked into the vacuum chamber through the sampling hole and transmitted through the ion transmission capillary 23, and the ion funnel is arranged inside the chamber, and its entrance is close to the exit of the ion transmission capillary 23. After the ions leave the ion transmission capillary 23 and enter the vacuum chamber, the ion funnel completes the ion pulling, gathering and separation from the impurities, and then transmits them to the front end of the lower chamber, thereby realizing a complete ion transmission function from atmosphere to vacuum. Specifically, after leaving the ion transmission capillary 23, the ions enter the ion funnel area, and after applying a specific voltage to the ion funnel component, a pseudopotential field for the ions to pass through can be formed between the circuit boards. Under the pseudopotential field formed by the ion funnel, the ions are gradually gathered in the gap between the ion funnels under the constraint of the electric field force and move forward. At the same time, under the guidance of the ion funnel, the advancing direction of the ions is inconsistent with the natural flow direction of the gas, so that the ions and the impurities are automatically separated during the advancing process. Finally, the charged particles are guided into the lower chamber by the ion funnel.

[0022] The atmospheric sampling component includes an atmospheric sampling interface composed of a cone-like baffle cone composed of three parts. The atmospheric sampling interface is generally conical, and the axis thereof is provided with coaxial through holes to embed metal capillaries as ion transmission capillaries 23: the baffle cone at the atmospheric sampling interface and the ion transmission capillary 23 are insulated, so that voltage can be applied independently to the ion transmission capillary and heating can be performed. The ion funnel part is composed of two printed circuit boards 9 and two E-shaped fixing parts 8, one side of the printed circuit board 9 is a patch surface, and the other side is a working surface. The working surfaces of the two printed circuit boards 9 are relatively parallel and fixed on the E-shaped fixing part 8, and the plate gap formed becomes an ion transmission channel. As the spacing between the discharge electrodes on the working surface narrows, the ion flow is also converged and focused, and finally an ion beam is formed and transmitted to the lower cavity through the small holes between the cavities.

[0023] The gas blocking cone at one end facing the atmosphere is composed of three parts, namely, the upper cone 15, the lower cone 16, and the cone disk 10. The upper cone 15 is conical, the lower cone 16 is truncated, and the cone disk 10 is cylindrical. The three are screwed and connected in sequence. The upper cone 15 and the lower cone 16 are made of aluminum alloy, and the cone disk 10 is made of stainless steel; wherein the upper cone 15 and the lower cone 16 are blocked by an insulating disk 17. There is a coaxial through hole in the center of the three for the ion transmission capillary 23 to pass through. The ion transmission capillary 23 is made of stainless steel, the opening of the upper cone 15 is consistent with the outer diameter of the ion transmission capillary 23, and the inner diameter can be changed according to different experiments and air pressure requirements. The opening space at the lower cone 16 and the cone disk 10 is increased successively. In a specific embodiment, the opening diameter of the upper cone 15 is 2mm, the outer diameter of the ion transmission capillary 23 is 2mm, and the inner diameter is between 1mm-0.4mm.

[0024] The upper cone 15, the lower cone 16, the cone disk 16, and the cavity are sealed with rubber O-rings of different sizes to prevent leakage and improve the overall vacuum of the cavity. Insulating sheets are provided at the junction of the upper cone 15 and the lower cone 16 and at the junction of the cone disk 10 and the ion transmission capillary 23 for separation. The insulating sheet is made of polyetheretherketone, so that the ion transmission capillary 23 can be applied with an independent voltage to improve the ion transmission efficiency.

[0025] A heating and temperature sensing integrated device is provided on the ion transmission capillary 23 of the opening section of the lower cone 16 and the cone disk 10 to heat and control the temperature of the ion transmission capillary 23, thereby helping the desolvation of the sample ion clusters. The heating element 24 used in the heating and temperature sensing integrated device is made of alumina ceramic material, and the temperature control uses a thermocouple external data acquisition device for real-time monitoring and temperature adjustment, which can control the temperature of the ion transmission capillary between 24-400°C.

[0026] 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.

[0027] The vacuum ion funnel assembly includes two printed circuit boards 9 and a circuit board fixing part. The printed circuit board 9 is mainly made of Rogers sheet material, one side is the component patch welding surface, and the other side is the bare copper working surface. The working surface adopts the bare copper process, and the front-stage gate electrode 27, the radio frequency electrode 28, the wall electrode 29, and the back-stage gate electrode 30 are engraved on the circuit board. The patch surface adopts the gold immersion process, which is used to weld various components to form an effective circuit. After the two printed circuit boards 9 are mirrored relative to each other, the E-shaped fixing part 8 is used as the circuit board fixing part to lock and fix the printed circuit board 9 to one side of the cone disk 10. The E-shaped fixing part 8 has a through threaded hole 25, and the printed circuit board 9 also has a through hole 26 of the same size. After aligning the opening of the circuit board with the opening of the E-shaped part, use a screw to position it, and tighten the nut on the screw to completely fix the circuit board on the E-shaped part. The distance between the two printed circuit boards 9 can be controlled by the inserted E-shaped fixing member 8, which is made of aluminum alloy, and the thickness of the interlayer can be adjusted according to actual needs to control the distance between the two boards. In a specific embodiment, the distance between the two printed circuit boards 9 is maintained between 2mm and 3mm.

[0028] The printed circuit board 9 is respectively provided with a front-stage gate electrode, a wall electrode, a radio frequency 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 radio frequency signals RF+ and RF- of the same amplitude and opposite magnitude are applied to the radio frequency 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 passing state of the entire ion funnel, which is used to adjust the connection / disconnection state of the ion transmission path and avoid charge accumulation.

[0029] 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 2 mm hole facing the ion funnel outlet 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

[0030] 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 uses the pressure difference to suck the sample ionized by the atmospheric pressure ion source into the device, and then separates the ionized sample from the impurities through the transmission of the ion funnel, and gathers and pulls the ions to the next stage cavity. The present invention is an ion transmission device that can be used from atmospheric pressure to vacuum environment.

[0031] Specifically, when the device is used, it will be loaded on the front vacuum chamber of the instrument, wherein the conical disk 10 is used to isolate the atmospheric environment from the vacuum environment in the chamber, and the rear disk 2 and the fixed disk 6 fix the rear end of the device to the walls of the front vacuum chamber and the rear vacuum chamber. The sealing O-rings 5, 7, 11, 14, 18, 21, and 22 are used to block the gaps generated during the assembly process of the parts to reduce the amount of leakage under high pressure difference. The ions are sucked into the chamber through the ion transmission capillary 23, which is made of stainless steel and is covered with a heating element 24 made of alumina ceramic material to increase the temperature and promote the desolvation of the inhaled sample. After the ions enter the chamber from the atmospheric environment, they enter the ion mobility area composed of the printed circuit board 9. Here, the ionized sample will be gathered and transmitted by the ion funnel composed of the printed circuit board 9 and separated from other impurities entrained. Finally, the ions enter the lower chamber through the limiting hole 13. A detachable handle block 19 and a handle bar 20 are installed on the cone disk 10. They are a set of auxiliary mounting handles, and the purpose is to facilitate the user to pull and put the whole device when disassembling it. After the device is embedded in the cavity, the two can be removed from the cone disk 10 without affecting the normal use of the device.

[0032] 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 realizes ion transmission from normal pressure to reduced pressure vacuum environment through a metal capillary injection channel and by utilizing the natural air pressure difference. At the same time, there is a certain eccentricity between the atmospheric end injection port and the secondary ion transmission outlet 1, that is, the outlet of the ion funnel axis, in order 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 the printed circuit board technology is used to carry out directional guided transmission of ions; based on the pseudopotential effect of the radio frequency electric field, applying a certain radio frequency signal and a DC signal to the two-piece circuit board ion funnel assembly can effectively control the directional movement of charged particles, thereby realizing directional guided transmission of ions.

[0033] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. An ion transmission device for mass spectrometry and ion mobility spectrometry instruments, characterized in that: It includes an atmospheric sampling component, an ion transmission component and a vacuum chamber; the atmospheric sampling component includes an atmospheric sampling interface, which is generally conical, with an injection hole at its input end, and a coaxial through hole on its axis; the ion transmission component includes an ion transmission capillary and an ion funnel, the ion transmission capillary is embedded in the coaxial through hole through the injection hole, the ion funnel is arranged close to the outlet position of the ion transmission capillary, the ion funnel is located in the vacuum chamber, and the ion funnel includes 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 two printed circuit board working surfaces are relatively mirrored, and the printed circuit board is fixed to one side of the atmospheric sampling component through a fixing piece; During operation, after the sample to be tested is ionized by an external ion source, it is sucked into the vacuum chamber through the injection hole and transmitted through the ion transmission capillary. The ions are pulled, gathered, separated from the impurities by the ion funnel with applied voltage and then transmitted 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 according to claim 1, characterized in that: A front-stage gate electrode, a wall electrode, a radio frequency electrode and a rear-stage gate electrode are respectively arranged 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 passing 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.

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

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

5. The ion transmission device for mass spectrometry and ion mobility spectrometry 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 realize the control of ion transmission.

6. The ion transmission device for mass spectrometry and ion mobility spectrometry according to claim 4, characterized in that: The ion transmission capillary of the lower cone and the cone disk opening section is covered with a heating and temperature sensing integrated device to heat and control the temperature of the ion transmission capillary to help desolvation of 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 injection assembly by two E-type fixings.

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 on 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 a plurality of sealing O-rings, which are used to seal the interconnected parts of 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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