A DC ion steering module adapted to traveling wave ion mobility

Abstract

This invention belongs to the field of ion mobility and mass spectrometry technology, specifically a DC ion steering module adapted for traveling wave ion mobility. The steering structure consists of two types of PCBs: the first type of PCB has multiple rectangular DC electrodes, which form an electric field to guide ions to complete the steering by applying a DC voltage; the second type of PCB has a single rectangular radio frequency electrode, which radially constrains the ions by applying a radio frequency voltage, ensuring stable ion transport in the steering region. The fully modular PCB architecture adopted in this invention has significant advantages in terms of structural simplification, cost control, manufacturing consistency, and system integration. Relying on the DC electrode as the core steering module and combined with low ion transport loss, this structure can effectively improve the overall resolution of traveling wave ion mobility systems, providing a practical technical path for achieving high-resolution ion mobility analysis.

Description

Technical Field

[0001] This invention belongs to the field of ion mobility and mass spectrometry technology, specifically, it relates to a DC ion steering module adapted to traveling wave ion mobility. Background Technology

[0002] Ion mobility assays (IMS), as an analytical technique capable of rapidly separating and detecting charged particles in the gas phase, offer unique advantages such as label-free operation, non-targeted detection, and millisecond-level high-throughput analysis. Therefore, they have garnered widespread attention in various fields including safety monitoring, life sciences, environmental analysis, and materials research. IMS achieves separation based on differences in ion migration velocities in weak or varying electric fields. Its separation dimension is not directly related to mass, thus providing structural information for complex samples that differs from mass spectrometry. As analytical chemistry and mass spectrometry research continue to advance towards higher sensitivity, higher resolution, and faster analysis speeds, the technological advantages of IMS become increasingly prominent.

[0003] In recent years, as the research scope of biological systems has shifted from the whole organism to the tissue, cell, and even subcellular scale, the types, structural isomers, and spatial heterogeneity of sample molecules have gradually increased. Traditional mass spectrometry methods based on mass-to-charge ratio separation have certain limitations in identifying conformational isomers, isomers, or interference from complex matrices. Ion mobility, by measuring the collision behavior between ions and gas molecules, can provide information on the collision cross section (CCS) reflecting the size, shape, and conformation of molecules, making it an indispensable dimension in structural biology, metabolomics, and the study of complex natural products.

[0004] Currently, commercially available IMS instruments mainly include drift tube ion mobility spectrometry (DTIMS), waveguide ion mobility spectrometry (TWIMS), electrostatically retained ion mobility spectrometry (TIMS), and differential ion mobility spectrometry (FAIMS). Their basic principle can be summarized as follows: after ionization, the sample enters a migration region filled with inert gas. Under the influence of an applied electric field, ions migrate at velocities related to their collision cross-section and charge state. Distinction is achieved by detecting the arrival time of the ions. IMS can be directly coupled with mass analyzers such as time-of-flight mass spectrometry (TOF-MS) to achieve structure-mass dual-dimensional separation and characterization, significantly improving the resolution of complex samples while maintaining high sensitivity.

[0005] However, improving ion mobility resolution and its stability under high-throughput conditions still faces significant technical challenges. High-resolution IMS typically requires longer migration paths, more precise electric field control, or higher gas flow dynamics stability, leading to increasingly complex instrument structures and more stringent requirements for system stability, temperature control, and long-term operational consistency. Furthermore, different IMS modes cannot simultaneously achieve optimal speed, resolution, and ion utilization, meaning that current commercial IMS systems still fall short of fully meeting the demands of cutting-edge research in terms of high throughput, high stability, and high resolution. High instrument manufacturing costs, complex parameter optimization, and high maintenance and operation barriers also limit the widespread adoption and large-scale use of IMS in various fields.

[0006] Nevertheless, a few research teams internationally are exploring novel high-throughput, high-resolution IMS technologies, such as long-path folded drift tube (SLIM IMS), parallel migration channels, multiplexed ion mobility, and miniaturized integrated IMS. These conceptual technologies offer new possibilities for achieving rapid, high-resolution, and low-cost ion mobility analysis. However, these systems typically require strong engineering capabilities, advanced fabrication technologies, and long debugging and optimization cycles, making commercialization in the short term still quite challenging. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention proposes a DC ion steering module adapted to traveling wave ion mobility, which has a simple structure and low circuit requirements. This structure is positioned at the end of the traveling wave ion mobility capable of achieving efficient ion separation. By coupling with the traveling wave ion mobility, the DC ion steering module effectively redirects ions, stably transferring ions from the previous segment of the traveling wave ion mobility to the next segment, thereby achieving continuous ion separation. This structure, by coupling with the traveling wave ion mobility, can significantly extend the ion separation path while maintaining low cost and low operational complexity, thus improving ion resolution. The technical solution of this invention is described in detail below.

[0008] A DC ion deflection module adapted to traveling wave ion mobility comprises two types of PCBs. The first type is a DC PCB, consisting of two boards, which are respectively positioned in front of and to one side of the ion outlet of the preceding traveling wave ion mobility segment. Multiple DC electrodes are arranged on the DC PCB, and an electric field is formed by applying a DC voltage to guide ion deflection, allowing ions to enter the next traveling wave ion mobility segment. The second type is a radio frequency (RF) PCB, consisting of two boards, which are symmetrically positioned above and below the ion outlet of the preceding traveling wave ion mobility segment. RF electrodes are arranged on the RF PCB, and an RF voltage is applied to radially constrain ions, ensuring stable ion transport within the turning region. The arrangement direction of the DC electrodes on the two DC PCBs is parallel to the ion transport direction in the preceding and following traveling wave ion mobility segments, respectively.

[0009] In this invention, the traveling wave ion mobility includes several circuit boards with traveling wave separation electrodes and radio frequency confinement electrodes drawn on their working surfaces. The circuit boards enclose a spatially symmetrical hollow ion transport channel. On each circuit board, the radio frequency confinement electrode consists of two elongated rod electrodes arranged radially along the ion transport channel. The traveling wave separation electrode is arranged between the two elongated rod electrodes and consists of multiple sets of spaced metal electrodes. The metal electrodes are arranged at intervals along the axial direction of the ion transport channel. Starting from any end, several adjacent metal electrodes form a group. Electrodes within each group are independent and not connected to each other. Electrodes with the same number in different groups are connected in series to form a circuit.

[0010] In this invention, the size and number of the DC electrodes can be flexibly designed according to the different mass-to-charge ratios and collision cross-sectional area (CCS) values ​​of the ions to be separated, and different DC voltages (gradient DC voltages) can be applied to different DC electrodes on the two DC PCBs respectively, which can further improve ion deflection efficiency and reduce ion transport loss.

[0011] In this invention, several DC electrodes on two DC PCBs are arranged in parallel at intervals.

[0012] In this invention, a rectangular radio frequency electrode is disposed on a radio frequency PCB board.

[0013] In this invention, the effective length of the traveling wave ion mobility is extended by connecting multiple DC ion steering modules adapted to the traveling wave ion mobility in series between the traveling wave ion mobilitys. By configuring different numbers of DC ion steering modules, the effective length of the traveling wave ion mobility can be extended in multiple stages within a limited space, thereby obtaining a longer ion separation path and improving resolution.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs a special DC ion steering module design to achieve ion steering. Compared with the traveling wave driven steering method, the requirements for the circuit are significantly reduced, the system is more simplified, and the operation is more convenient.

[0015] The device of this invention has a simple structure and is easy to implement, and can be reliably coupled with existing traveling wave ion mobility. It can effectively achieve ion deflection without adding extra circuitry and extend the ion separation path within a limited space, thereby improving resolution. Attached Figure Description

[0016] Figure 1 A schematic diagram of a DC ion steering module adapted to traveling wave ion mobility.

[0017] Figure 2 This is the overall structural assembly drawing.

[0018] The attached figures are labeled as follows: 1-DC turning structure, 2, 3-Traveling wave ion mobility, 4-Schematic diagram of voltage application method for DC turning structure, 5-3D schematic diagram of DC turning structure. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] Example 1

[0021] In this embodiment, a traveling-wave ion mobility 2 is first provided, comprising four circuit boards with traveling-wave separation electrodes and radio-frequency confinement electrodes drawn on their working surfaces. These circuit boards enclose a cuboid ion transport channel. On each circuit board, the radio-frequency confinement electrode consists of two elongated rod electrodes arranged radially along the ion transport channel, used for radial confinement of the transported ions. The traveling-wave separation electrode is positioned between the two elongated rod electrodes. The traveling-wave separation electrode consists of multiple sets of spaced-apart metal electrodes, arranged axially along the ion transport channel. Starting from any end, eight adjacent metal electrodes form a group, and the metal electrodes within each group are numbered 1-8. Electrodes within each group are independent and not connected. Electrodes with the same number from different groups are connected in series to form a circuit. This traveling-wave ion mobility can achieve highly efficient ion separation. However, the effective length of the traveling-wave ion mobility directly determines the ion separation path, thus affecting the separation efficiency and resolution. If it is necessary to further extend the ion separation path, the physical length of the traveling-wave ion mobility 2 usually needs to be increased accordingly. This not only places higher demands on the vacuum system, but also requires a longer vacuum chamber to accommodate the extended octupole structure, resulting in a significant increase in equipment design costs and inconvenience in overall assembly and maintenance.

[0022] Therefore, the present invention further provides a DC ion steering module adapted to the aforementioned traveling wave ion mobility 2, the specific structure of which is shown in Figure 1. This DC steering structure 1 is located at the end of the traveling wave ion mobility 2. Compared with the conventional traveling wave driven steering structure, this structure uses a DC electrode as the core steering module. By coupling with the existing traveling wave ion mobility 2, it can stably guide ions in the preceding traveling wave ion mobility 2 to the following traveling wave ion mobility 3, achieving continuous ion transport and separation.

[0023] Specifically, the DC turning structure 1 consists of two types of PCBs: the first type of PCB has multiple rectangular DC electrodes, which form an electric field for ion turning by applying DC voltage; the second type of PCB has a single rectangular radio frequency electrode, which radially constrains the ions by applying radio frequency voltage, ensuring stable ion transport within the turning region. Effective ion turning can be achieved by configuring the position, number, size, and amplitude of the DC electrodes. When ions move along the traveling wave ion mobility to the DC turning structure composed of the two types of PCBs, the electric field formed by the DC electrodes will deflect the ions. As shown in Figure 1, the two DC PCBs are located in front of and to the right of the ion outlet, respectively, generating downward and leftward electric field deflection forces on the ions, causing them to enter the next segment of the traveling wave ion mobility. Simultaneously, radio frequency PCBs are symmetrically arranged above and below the ion outlet, confining the ions to the central region by applying radio frequency voltage. By rationally designing the structural parameters of the DC electrodes, the ion path deflection can be made more precise, reducing ion loss during the turning process.

[0024] In this invention, the electrode size, number of electrodes, and power application method in the DC turning structure 1 can be flexibly designed according to different separation requirements. In a specific embodiment, the turning structure can be configured with two sets of DC electrodes, each set consisting of 7 small electrodes. A gradient voltage is applied to the DC electrodes: in the first set, the voltage of electrode 1 is set to Udc, electrode 2 to Udc×(6 / 7), decreasing sequentially until electrode 7 is Udc×(1 / 7); the voltage setting method for the second set of DC electrodes is the same, with electrode 8 at Udc, electrode 9 at Udc×(6 / 7), decreasing sequentially until electrode 14 is Udc×(1 / 7). A conventional RF voltage, such as 1 MHz, 350 V, is applied to the upper and lower RF PCBs to provide radial constraint. Specific assembly methods and voltage application methods are as follows... Figure 2 As shown, the DC turning structure 1 is located between two traveling wave ion mobility 2, receiving ions from the previous stage octupole. Through the special potential setting of the turning structure, the ions are turned and enter the next stage octupole.

[0025] The specific embodiments of the present invention have been described above. It can be seen that the DC ion steering module adapted to traveling wave ion mobility developed by the present invention can couple with traveling wave ion mobility, thereby extending the ion separation path, without incurring additional burden on the traveling wave circuit. This reduces system cost, simplifies electronic control, and maintains good ion transport efficiency and separation performance.

[0026] It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in these embodiments can be arbitrarily combined with each other.

Claims

1. A DC ion steering module adapted to traveling wave ion mobility, characterized in that, It consists of two types of PCBs. The first type is a DC PCB, consisting of two pieces connected perpendicularly to each other in an L-shape. These pieces are positioned in front of and to one side of the ion outlet of the first traveling wave ion mobility segment. Multiple DC electrodes are arranged on the DC PCB, and an electric field is formed by applying a DC voltage to guide the ions into the second traveling wave ion mobility segment. The second type is a radio frequency (RF) PCB, consisting of two pieces arranged parallel to each other, symmetrically positioned above and below the ion outlet of the first traveling wave ion mobility segment. Radio frequency (RF) electrodes are arranged on the RF PCB, and a radio frequency (RF) voltage is applied to radially constrain the ions, ensuring stable ion transport within the turning region. The arrangement direction of the DC electrodes on the two DC PCBs is parallel to the ion transport direction in the first and second traveling wave ion mobility segments, respectively.

2. The DC ion steering module adapted to traveling wave ion mobility according to claim 1, characterized in that, The traveling wave ion mobility comprises several circuit boards with traveling wave separation electrodes and radio frequency confinement electrodes drawn on their working surfaces. The circuit boards enclose a spatially symmetrical hollow ion transport channel. On each circuit board, the radio frequency confinement electrode consists of two elongated rod electrodes arranged radially along the ion transport channel. The traveling wave separation electrode is located between the two elongated rod electrodes and consists of multiple sets of spaced metal electrodes. The metal electrodes are arranged at intervals along the axial direction of the ion transport channel. Starting from any end, several adjacent metal electrodes form a group. Electrodes within each group are independent and not connected to each other. Electrodes with the same number from different groups are connected in series to form a circuit.

3. The DC ion steering module adapted to traveling wave ion mobility according to claim 1, characterized in that, Gradient DC voltages are applied to the DC electrodes on the two DC PCBs respectively.

4. The DC ion steering module adapted to traveling wave ion mobility according to claim 1, characterized in that, Several DC electrodes are arranged in parallel with spacing on two DC PCB boards.

5. The DC ion steering module adapted to traveling wave ion mobility according to claim 1, characterized in that, A rectangular radio frequency electrode is set on a radio frequency PCB board.

6. The DC ion steering module adapted to traveling wave ion mobility according to claim 1, characterized in that, The effective length of the traveling wave ion mobility is extended by connecting multiple DC ion steering modules in series between the traveling wave ion mobilitys.

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