An ion funnel-based collision reaction cell

Abstract

The present invention relates to a collision reaction cell based on an ion funnel, comprising: a cavity, an ion funnel, a power supply board, an inlet lens, and an outlet lens. The cavity, the inlet lens, and the outlet lens enclose a closed space. The ion funnel and the power supply board are disposed within the closed space. The power supply board is connected to the ion funnel. The inlet lens is provided with a hole for ions to enter, and the outlet lens is provided with a hole for ions to fly out. The bottom of the cavity is provided with a hole for feeding collision gas, and the ion funnel is provided with a hole serving as an ion channel. Compared with the multi-pole rod technology commonly used in current collision reaction cells, the ion funnel adopted in the present invention can manipulate ions at a higher gas pressure, allowing ions to collide and dissociate with greater kinetic energy, and can achieve better performance than multi-pole rods.

Description

Technical Field

[0001] The present invention relates to the technical field of mass spectrometers, and particularly relates to a collision reaction cell based on an ion funnel. Background Art

[0002] Mass spectrometers, electron microscopes, nuclear magnetic resonance instruments, etc. all belong to high-end scientific instruments. At present, tens of thousands of mass spectrometers are imported into China every year. Among them, the liquid chromatography-tandem quadrupole mass spectrometer has both qualitative and quantitative functions and is widely used in industries such as pharmaceuticals, food safety, inspection and quarantine, and clinical testing. However, the liquid chromatography-tandem quadrupole mass spectrometer is also one of the mass spectrometers with relatively high R & D difficulty. The difference between a triple quadrupole mass spectrometer and a single quadrupole mass spectrometer lies in its key component - the collision reaction cell. The collision reaction cell is a place where parent ions undergo collision dissociation and chemical reactions to produce product ions. The collision reaction cell involves multiple functions such as collision, focusing, dissociation, and transmission. The adoption of the collision reaction cell enables the instrument to form two-stage mass spectrometry information of parent and daughter ions, thus having a stronger substance identification ability. Currently, the commonly used collision reaction cell structures are mainly multi-pole rods, including quadrupole rods, hexapole rods, octopole rods, etc. However, the currently commonly used multi-pole rod technology in the collision reaction cell cannot manipulate ions at higher gas pressures, and the kinetic energy of ion collision dissociation is limited.

[0003] The ion funnel is a technology invented in the last century with high focusing and transmission efficiency. The ion funnel is currently widely used in the ion transmission at the atmospheric pressure-vacuum interface. The ion funnel can manipulate ions at a higher gas pressure compared to multi-pole rods, allowing ions to undergo collision dissociation with a greater kinetic energy. Theoretically, using it in a collision reaction cell will achieve better performance than multi-pole rods. Summary of the Invention

[0004] In order to achieve the above objects and other advantages of the present invention, the object of the present invention is to provide a collision reaction cell based on an ion funnel, including: a cavity, an ion funnel, a power supply board, an inlet lens, and an outlet lens. The cavity, the inlet lens, and the outlet lens enclose a closed space. The ion funnel and the power supply board are placed in the closed space. The power supply board is connected to the ion funnel. The inlet lens is provided with a hole for ions to enter, and the outlet lens is provided with a hole for ions to fly out. The bottom of the cavity is provided with a hole for feeding collision gas, and the ion funnel is provided with a hole serving as an ion channel.

[0005] Further, the ion funnel includes a plurality of metal pole pieces and insulating sheets. The insulating sheets are placed between adjacent metal pole pieces. The metal pole pieces and the insulating sheets are provided with holes serving as ion channels.

[0006] Further, from the side of the entrance lens to the side of the exit lens, the DC voltage output by the power supply plate is linearly distributed among all the metal pole pieces, forming an axial electric field to drive the ions to move from the entrance to the exit;

[0007] The amplitudes of the RF voltages output by the power supply plate to all the metal pole pieces are the same, and the phases of the RF voltages output by the power supply plate to adjacent metal pole pieces are opposite.

[0008] Further, the inner diameter of the holes on the side of the ion funnel close to the entrance lens is larger than the inner diameter of the holes on the side of the ion funnel close to the exit lens.

[0009] Further, the ion funnel includes a channel section and a focusing section. The channel section is close to the side of the entrance lens, and the inner diameters of the holes in the channel section are equal. The focusing section is close to the side of the exit lens, and the inner diameter of the holes in the focusing section gradually decreases along the direction from the entrance lens to the exit lens.

[0010] Further, the metal pole pieces of the ion funnel are arranged in an off-axis manner.

[0011] Further, the ion channel of the ion funnel includes an arc-shaped ion channel.

[0012] Further, the entrance lens is coaxial with the entrance of the ion funnel, and the exit lens is coaxial with the exit of the ion funnel.

[0013] Further, it further includes an entrance ion channel section and an exit ion channel section. The entrance ion channel section and the exit ion channel section include several metal pole pieces. The inner diameter of the entrance ion channel section is equal to the inner diameter of the hole at the entrance of the ion channel, and the inner diameter of the exit ion channel section is equal to the inner diameter of the hole at the exit of the ion channel.

[0014] Further, the arc-shaped ion channel is a 90° arc-shaped ion channel or a 180° arc-shaped ion channel.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] The collision reaction cell provided by the present invention is based on an ion funnel. Compared with the multi-pole rod technology commonly used in current collision reaction cells, it can manipulate ions at a higher gas pressure, allowing ions to undergo collision dissociation with greater kinetic energy, and can achieve better performance than multi-pole rods.

[0017] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly and implement it in accordance with the content of the specification, the following will describe in detail with reference to the preferred embodiments of the present invention and the accompanying drawings. The specific implementation manners of the present invention are given in detail by the following embodiments and their accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present invention and form a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1 It is a schematic diagram of a collision reaction cell based on an ion funnel for Embodiment 1;

[0020] Figure 2 It is a schematic diagram of the application principle of the DC voltage and RF voltage of the ion funnel;

[0021] Figure 3 It is a schematic diagram of a 90° ion channel;

[0022] Figure 4 It is a schematic diagram of a 180° ion channel.

[0023] In the figure: 1, cavity; 2, ion funnel; 21, metal pole piece; 22, inlet ion channel section; 23, outlet ion channel section; 3, power supply board; 4, inlet lens; 5, outlet lens. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] Next, in combination with the drawings and specific embodiments, the present invention will be further described. It should be noted that, on the premise of no conflict, the following-described embodiments or technical features can be arbitrarily combined to form new embodiments.

[0025] In the subsequent description, the use of suffixes such as "module", "component" or "unit" for representing elements is only for the convenience of the description of the present invention, and it has no specific meaning itself. Therefore, "module", "component" or "unit" can be used interchangeably.

[0026] Embodiment 1

[0027] A collision reaction cell based on an ion funnel 2, as Figure 1 shown, includes: a cavity 1, an ion funnel 2, a power supply board 3, an inlet lens 4, and an outlet lens 5. The cavity 1, the inlet lens 4, and the outlet lens 5 enclose a closed space. The inlet lens 4 and the outlet lens 5 can be formed in good seal with the cavity 1 by means such as gluing or screw pressing with a sealing ring to ensure that the internal pressure of the collision cell, which is different from the vacuum environment where it is located, is maintained.

[0028] The ion funnel 2 and the power supply board 3 are placed in a sealed space. The power supply board 3 is connected to the ion funnel 2. The entrance lens 4 is provided with holes for ions to enter, and the exit lens 5 is provided with holes for ions to fly out. The ion funnel 2 is provided with holes serving as ion channels. Ions can only enter through the holes on the entrance lens 4 and fly out through the holes on the exit lens 5. On one side of the bottom of the cavity 1 near the entrance lens 4, there are holes for feeding collision gas, which are used to introduce collision gas for collision dissociation reactions of ions, etc.

[0029] The ion funnel 2 includes a plurality of metal pole pieces 21 and insulating sheets. The plurality of metal pole pieces 21 are stacked together, and the insulating sheets are placed between adjacent metal pole pieces 21 for good insulation. The metal pole pieces 21 and the insulating sheets are provided with holes serving as ion channels, such as circular holes are arranged in the middle of each metal pole piece 21 as ion channels.

[0030] The inner diameter of the holes on the side of the ion funnel 2 close to the entrance lens 4 is larger than the inner diameter of the holes on the side of the ion funnel 2 close to the exit lens 5. Preferably, the ion funnel 2 includes a channel section and a focusing section. The channel section is close to the entrance lens 4, and the inner diameters of the holes in the channel section are equal. The focusing section is close to the exit lens 5, and the inner diameter of the holes in the focusing section gradually decreases along the direction from the entrance lens 4 to the exit lens 5 to facilitate ion focusing.

[0031] The power supply board 3 is specifically a power supply PCB board, and the power supply PCB board supplies a DC voltage and an RF voltage to the metal pole pieces 21. The application principles of the DC voltage and the RF voltage are as Figure 2 shown. Among them, the DC voltage is linearly distributed among all the metal pole pieces 21 from the side of the entrance lens 4 to the side of the exit lens 5 to form an axial electric field to drive ions to move from the entrance to the exit; while the RF voltage is set according to the rule that the amplitudes are the same and the phases of adjacent metal pole pieces 21 are opposite.

[0032] In order to avoid noise interference such as neutral particles during the process, the metal pole pieces 21 of the ion funnel 2 can be arranged in an off-axis manner. Preferably, the ion channel of the ion funnel 2 includes an arc-shaped ion channel. For example, a 90° arc-shaped ion channel as shown in Figure 3 can be formed, or an 180° arc-shaped ion channel as shown in Figure 4 can be formed. It should be understood that ion channels with other radian values can be designed according to actual needs.

[0033] When an arc-shaped ion channel is set, it is necessary to ensure that the designs and layouts of the cavity 1, the entrance lens 4, and the exit lens 5 change with the shape of the ion funnel 2, and ensure that the entrance lens 4 is coaxial with the entrance of the ion funnel 2, and the exit lens 5 is coaxial with the exit of the ion funnel 2.

[0034] It should be noted that when the ion channel is set to an arc shape, generally an inlet ion channel section 22 is provided at the inlet of the ion channel, and an outlet ion channel section 23 is provided at the outlet of the ion channel. The inlet ion channel section 22 and the outlet ion channel section 23 include a plurality of metal pole pieces 21. The inner hole diameter of the inlet ion channel section 22 is equal to the inner hole diameter at the inlet of the ion channel, and the inner hole diameter of the outlet ion channel section 23 is equal to the inner hole diameter at the outlet of the ion channel. The inlet ion channel section 22 is mainly used to generate good collision cooling, which is convenient for reducing the noise of ions entering the next-stage arc-shaped channel and improving the signal-to-noise ratio. The outlet ion channel is mainly used to form good ion focusing, which is convenient for the ion beam to fly out from the outlet lens 5.

[0035] Common multipole rod structures and ion funnels 2 both use the application of a radio frequency electric field to form a pseudopotential field to achieve the ion focusing effect. The voltage magnitude of the pseudopotential field directly determines the binding ability of this structure to charged ions. The commonly used multipole rod structure has a pole rod diameter of 5 - 10 mm, and the maximum value of the multipole rod pseudopotential field is:

[0036]

[0037] where n is the number of pairs of multipole rod electrodes; q and m are the charge and mass of the ion respectively; V rf is the amplitude of the radio frequency voltage; r0 and r are the field circle radius and pole rod radius of the multipole rod respectively.

[0038] For example, for the commonly used 9.4 mm quadrupole collision rod group structure, its inscribed circle r0 is 8.32 mm, and the voltage is generally about 0.7 - 1.2 MHz.

[0039]

[0040] And for the commonly used ion funnel 2, the maximum value of the pseudopotential field is:

[0041]

[0042] d is the spacing between the annular electrode pole pieces; δ = d / π.

[0043] For example, for the commonly used ion funnel 2 model, generally d = 1 mm, then

[0044]

[0045] As can be seen from the above calculations, for ions with the same mass-to-charge ratio (q / m, or z / m), when a radio frequency power supply with the same amplitude and frequency is applied, the maximum value of the pseudopotential field generated by the ion funnel 2 is dozens of times that of the common multipole rod design, resulting in a stronger ion confinement ability. A stronger confinement ability means that a higher collision cell gas pressure can be adopted, thereby generating more efficient ion-molecule collisions. At the same time, it means a more efficient focusing and transmission efficiency of parent ions and daughter ions, and less ion loss. Therefore, it is expected that the performance of the collision reaction cell can be significantly improved.

[0046] The collision reaction cell based on the ion funnel provided by the present invention can manipulate ions at a higher gas pressure compared to the collision reaction cell based on the common multipole rod technology, allowing ions to collide and dissociate with greater kinetic energy. Theoretically, better performance can be achieved in the collision reaction cell than that of the multipole rod.

[0047] The above is only for the embodiments of this specification and is not intended to limit one or more embodiments of this specification. For those skilled in the art, various changes and modifications can be made to one or more embodiments of this specification. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of one or more embodiments of this specification shall be included within the scope of the claims of one or more embodiments of this specification. One or more embodiments of this specification, one or more embodiments of this specification, one or more embodiments of this specification, one or more embodiments of this specification.

Claims

1. An ion funnel-based collision reaction cell, characterized in that Comprising: A cavity, an ion funnel, a power supply plate, an entrance lens, and an exit lens. The cavity, the entrance lens, and the exit lens enclose a sealed space. The ion funnel and the power supply plate are disposed within the sealed space. The power supply plate is connected to the ion funnel. The entrance lens is provided with a hole for ions to enter, and the exit lens is provided with a hole for ions to fly out. The bottom of the cavity is provided with a hole for feeding in collision gas, and the ion funnel is provided with a hole serving as an ion channel. From the side of the entrance lens to the side of the exit lens, the DC voltage output by the power supply plate is linearly distributed among all the metal pole pieces, forming an axial electric field to drive the ions to move from the entrance to the exit. The amplitudes of the RF voltages output by the power supply plate to all the metal pole pieces are the same, and the phases of the RF voltages output by the power supply plate to adjacent metal pole pieces are opposite. The inner diameter of the hole on the ion funnel near the entrance lens side is larger than the inner diameter of the hole on the ion funnel near the exit lens side. The entrance lens is coaxial with the entrance of the ion funnel, and the exit lens is coaxial with the exit of the ion funnel. The metal pole pieces of the ion funnel are arranged in an off-axis manner. The ion channel of the ion funnel includes an arc-shaped ion channel. It further includes an entrance ion channel section and an exit ion channel section. The entrance ion channel section and the exit ion channel section include a plurality of metal pole pieces. The inner diameter of the hole in the entrance ion channel section is equal to the inner diameter of the hole at the entrance of the ion channel, and the inner diameter of the hole in the exit ion channel section is equal to the inner diameter of the hole at the exit of the ion channel.

2. The collision reaction cell based on an ion funnel according to claim 1, wherein: The ion funnel includes a plurality of metal pole pieces and insulating sheets. The insulating sheets are disposed between adjacent metal pole pieces. The metal pole pieces and the insulating sheets are provided with holes serving as ion channels.

3. The collision reaction cell based on an ion funnel according to claim 1, characterized in that, The arc-shaped ion channel is a 90° arc-shaped ion channel or a 180° arc-shaped ion channel.

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