An ion steering module adapted for traveling wave ion mobility without requiring direct current protection

Abstract

This invention belongs to the field of mass spectrometry and ion mobility spectroscopy analysis technology, specifically an ion redirection module adapted to traveling wave ion mobility without DC protection. It includes at least two interconnected redirection mobility tubes, each comprising several circuit boards. The central area of ​​each circuit board is decorated with radio frequency (RF) confinement electrodes and traveling wave separation electrodes. At the redirection point where the two redirection mobility tubes intersect, the RF confinement electrodes are bent at the corresponding angle, and the traveling wave separation electrodes are arranged in pairs, forming a symmetrical triangular geometry. The arrangement of the RF confinement electrodes and traveling wave separation electrodes at the redirection point ensures the continuity of the RF electric field and the traveling wave electric field, enabling ions to be redirected along the electrode arrangement direction while achieving ion separation. This invention features a simple structural design, requires fewer components, has a concise circuit design, and offers greater scalability, achieving ion redirection without hindering the separation function of the ion mobility module.

Description

Technical Field

[0001] This invention relates to the fields of mass spectrometry and ion mobility spectrometry, and more specifically, to an ion deflection module adapted to traveling wave ion mobility without the need for DC protection. Background Technology

[0002] Traveling-wave ion mobility (TWIM) is a gas-phase ion separation method driven by a dynamic electric field, widely used in mass spectrometry-ion mobility systems to enhance the separation capabilities and analytical dimensionality of complex samples. Unlike traditional drift tube ion mobility techniques that employ a constant DC electric field, TWIM applies a pulsed DC signal with a time-phase delay to a series of spatially distributed electrodes. This creates an axially propagating potential wave in a buffer gas-filled channel, driving ions forward and achieving migration separation. Because different ions exhibit varying responses to the traveling-wave potential in a gaseous medium, TWIM can effectively distinguish isomers, isomeric isomers, and components in complex mixtures while maintaining high ion throughput. This technique offers advantages such as flexible separation path expansion, high compatibility with various mass spectrometry systems, and suitability for high-resolution and high-throughput analysis, thus demonstrating significant application value in proteomics, metabolomics, environmental analysis, and drug analysis.

[0003] In ion mobility spectroscopy, the separation capability of traveling wave ion mobility is typically proportional to the square root of the total length of the ion mobility tube. Therefore, the most direct way to improve mobility performance is to increase the length of the ion transport path. However, due to the limitations of instrument physical space, it is impossible to extend the ion mobility tube length indefinitely in a straight line. In this case, employing a steering structure design becomes an effective and necessary technical approach, significantly increasing the ion migration distance within a limited space, thereby achieving higher separation performance and resolution. Summary of the Invention

[0004] To address the shortcomings of the existing technology, the present invention aims to provide an ion deflection module adapted to traveling wave ion mobility that does not require DC protection. The present invention achieves the change of ion transport direction by adjusting the electrode arrangement. It has a simple structural design, requires fewer components, has a concise circuit design, and is more expandable. It can achieve ion deflection without hindering the separation function of the ion mobility module.

[0005] The technical solution of the present invention is described in detail below.

[0006] An ion deflection module adapted to traveling wave ion mobility without DC protection includes at least two interconnected deflection mobility tubes. Each deflection mobility tube includes several circuit boards. The central region of the circuit boards is decorated with radio frequency confinement electrodes and traveling wave separation electrodes. The traveling wave separation electrodes are arranged at intervals along the axial direction of the ion transport channel, and the radio frequency confinement electrodes extend radially along the ion transport channel. The circuit boards enclose a spatially symmetrical hollow ion transport channel. Radio frequency voltage signals and traveling wave voltage signals are applied to the radio frequency confinement electrodes and the traveling wave separation confinement electrodes, respectively, to form radio frequency electric fields and traveling wave electric fields for confining the movement range of ions and performing ion separation. At the turning point where the two turning mobility tubes are joined together, the radio frequency confinement electrode bends at the corresponding corner, and the traveling wave separation electrode is set in pairs, forming a symmetrical triangular geometry. The arrangement of the radio frequency confinement electrode and the traveling wave separation electrode at the turning point ensures the continuity of the radio frequency electric field and the traveling wave electric field at the turning point, so that ions can be turned along the electrode arrangement direction while achieving ion separation.

[0007] In this invention, the traveling wave separation electrode is composed of several electrode groups. Starting from any end, n adjacent electrodes form a group. The metal electrodes in each group are numbered 1-n. The electrodes in 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.

[0008] In this invention, a traveling wave voltage signal is applied to each electrode group of the traveling wave separation electrode. The traveling wave voltage signal is a unipolar pulsed DC voltage signal with a fixed phase delay, causing the traveling wave potential to propagate continuously along the ion transport direction. The propagation speed of the traveling wave is determined by both the electrode spacing and the phase delay, while its amplitude is determined by the magnitude of the applied voltage.

[0009] In this invention, the traveling wave voltage signal is a periodically changing voltage signal, and its waveform is a sine wave, square wave, triangular wave or chopper signal.

[0010] In this invention, the radio frequency confinement electrode consists of a set of long strip rod electrodes that are geometrically symmetrical in space, and the electrodes are insulated from each other and independent.

[0011] In this invention, the radio frequency voltage applied to the radio frequency confinement electrode is an alternating radio frequency voltage with a fixed amplitude and a frequency on the order of megahertz; the radio frequency voltage signals applied to adjacent or opposing electrodes are in opposite phase, thereby forming a radial effective potential well in the ion transport channel and achieving stable confinement of ions.

[0012] In this invention, a DC bias voltage is superimposed on the radio frequency signal to adjust the ion transport conditions.

[0013] In this invention, the cross-section of the hollow ion transport channel is circular, rectangular, or other polygonal. The specific channel cross-sectional shape depends on the required number of multipole electrodes and the arrangement of multipole electrodes on the circuit board. During operation, ions pass through the geometric center region of the channel and complete the separation process under the combined action of the traveling wave electric field and the radio frequency confinement electric field.

[0014] In this invention, the degree of ion separation and throughput performance are adjusted by adjusting the wave height, wave velocity, and waveform phase difference of the traveling wave voltage signal.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention eliminates the need for DC protection electrodes, achieving effective radial confinement of ions through the synergistic effect of radio frequency electric fields and traveling wave electric fields. This avoids the dependence on DC protection electrodes in traditional structures and significantly simplifies electrode structure and circuit design.

[0016] This invention achieves ion redirection through an approximate electrode structure, maintaining the continuity of the traveling wave electric field and the radio frequency electric field. The electrode structure is simple and highly integrated, and can be directly integrated into a circuit board or modular structure, reducing the number of mechanical parts and lowering processing, assembly, and maintenance costs.

[0017] The ion deflection module of this invention can change the ion transport direction by adjusting the electrode arrangement while ensuring separation capability. When deflection is required, the arrangement of the traveling wave separation electrode and the radio frequency confinement electrode at the deflection point is modified according to the dimensions of the deflection point to ensure the continuity of the radio frequency electric field and the traveling wave electric field at the deflection interface, ensuring that ions are not lost or that the separation capability is not significantly reduced during the deflection process.

[0018] The geometry and size of the ion transport channel of this invention can be flexibly designed according to requirements, and it is easy to integrate with different types of mass spectrometry systems or pre- and post-stage ion optics devices, exhibiting extremely high scalability and compatibility. Furthermore, by flexibly adjusting the traveling wave and radio frequency parameters, an optimal trade-off can be achieved between high-throughput transmission and high-resolution separation, making it suitable for various analytical scenarios and for the migration and separation of ions in a variety of samples. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the linear electrode arrangement according to an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the arrangement of steering electrodes according to an embodiment of the present invention.

[0021] Figure 3 This is a circuit board design diagram for the turning point according to an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of a monolithic circuit board with integrated electrodes according to an embodiment of the present invention.

[0023] Figure 5 This is a schematic diagram of the assembly of a single diverting flow pipe according to an embodiment of the present invention.

[0024] Figure 6 This is a two-dimensional diagram of the flow pipe connection at the turning point in an embodiment of the present invention.

[0025] Figure 7 This is a three-dimensional diagram of the flow pipe connection at the turning point in an embodiment of the present invention.

[0026] The accompanying figures are labeled as follows: 1-Traveling wave separation electrode, 2-RF constraint electrode, 3-Traveling wave separation electrode at the turning point, 4-RF constraint electrode at the turning point, 5-Traveling wave separation electrode at the turning interface, 6, 7, 8, and 9 are the four irregularly shaped circuit boards required at the turning point, 10-Circuit drawing section, 11-Bayonet, 12-Bayonet teeth, 13-Through hole for fixing. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] Example 1

[0029] This invention provides an ion steering module adapted to traveling wave ion mobility without DC protection, the electrode structure of which is as follows: Figure 1 , Figure 2 As shown, this includes linear electrode arrangements and directional electrode arrangements.

[0030] In the linear transmission separation section, traveling wave separation electrode 1 and radio frequency confinement electrode 2 are arranged alternately on the same plane as shown in the diagram. Traveling wave separation electrode 1 consists of several electrode groups, each containing eight independent rectangular electrodes. Electrodes within a group are electrically isolated from each other, and electrodes of the same number in different groups are connected in series. For example, the first electrodes of each group are connected in series. A sinusoidal voltage of the same waveform is applied to the traveling wave separation electrode with the same number, and a sinusoidal voltage with a 45° phase delay is applied to the next numbered electrode, and so on, applying voltages to the eight traveling wave separation electrodes with different numbers. Radio frequency confinement electrode 2 is alternately applied with radio frequency voltages with a 180° phase difference. After all voltages are applied, an effective electric field is formed to confine and separate the radial motion of the ions.

[0031] In the corner transmission section, the traveling wave separation electrode 3 at the corner junction and the traveling wave separation electrode 1 in the straight transmission separation section have a similar structural arrangement, while the radio frequency constraint electrode 4 at the corner is bent according to the requirements of the corner. At the corner interface, the corner interface traveling wave separation electrode 5 is designed with a symmetrical triangular geometry according to the size and dimensions of the interface. The interface traveling wave separation electrodes 5 are placed in pairs and follow the phase difference with the other adjacent traveling wave separation electrodes.

[0032] The mechanical structure and electrodes are drawn as follows: Figure 3 and Figure 4 As shown: To achieve the steering mechanism, four irregularly shaped circuit boards 6, 7, 8, and 9 at the steering interface need to be assembled to form a mobility tube. In each circuit board, the central circuit drawing section 10 is used to draw the aforementioned traveling wave and RF confinement electrode, and bayonet 11 and locking teeth 12 are respectively provided on both sides for mutual locking and fixation. The circuit board has additional through holes 13 for reinforcement using fasteners after the ion mobility tube assembly is completed. This prevents loosening or disintegration of the connection due to vibration, external force squeezing, twisting, or other unforeseen factors during use.

[0033] Assembly scheme such as Figures 5 to 7 As shown: During assembly, simply confirm the working surface and wiring surface of one circuit board, align the locking teeth 12 of the other circuit board with the locking jaws 11, and press them firmly. Repeat this process for all four circuit boards to complete the installation of a single steering flow meter. To complete the entire steering module, the two assembled steering flow meters need to be aligned according to... Figure 6 , Figure 7 The sections are spliced ​​together in a specific way, and the cross-sections at the turning points must be aligned one by one to form a 90° turn.

[0034] During operation, the RF power supply and traveling wave power supply are connected to the assembled ion mobility tube according to the requirements. After pretreatment, the ionized sample is injected in batches at one end of the mobility tube using constant pulses. Drawn by the electric field of the mobility tube, the ions move from one end to the turning point, and then make a 90° turn under the constraint of the electric field before moving to the other end of the mobility tube to complete ion separation. The ions are then successively transported out of the mobility tube and transferred to subsequent instruments. When one batch of ions has completely exited the mobility tube, the next batch can be pulsed into the mobility tube. The entire process from the injection of a batch of ions into the mobility tube until they completely exit the tube constitutes one complete working cycle. This achieves the ion mobility separation function.

[0035] Specific embodiments of the present invention have been described above. 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 this application can be arbitrarily combined with each other.

Claims

1. An ion deflection module adapted to traveling wave ion mobility without DC protection, characterized in that, It includes at least two interconnected diverting mobility tubes, each of which includes several circuit boards. The central area of ​​the circuit boards is decorated with radio frequency confinement electrodes and traveling wave separation electrodes. The traveling wave separation electrodes are arranged at intervals along the axial direction of the ion transport channel, and the radio frequency confinement electrodes extend radially along the ion transport channel. The circuit boards enclose a spatially symmetrical hollow ion transport channel. Radio frequency voltage signals and traveling wave voltage signals are applied to the radio frequency confinement electrodes and the traveling wave separation confinement electrodes, respectively, to form radio frequency electric fields and traveling wave electric fields for confining the movement range of ions and performing ion separation. At the turning point where the two turning mobility tubes are joined together, the radio frequency confinement electrode bends at the corresponding corner, and the traveling wave separation electrode is set in pairs, forming a symmetrical triangular geometry. The arrangement of the radio frequency confinement electrode and the traveling wave separation electrode at the turning point ensures the continuity of the radio frequency electric field and the traveling wave electric field at the turning point, so that ions can be turned along the electrode arrangement direction while achieving ion separation.

2. The ion deflection module adapted to traveling wave ion mobility without DC protection according to claim 1, characterized in that, The traveling wave separation electrode consists of several electrode groups. Starting from any end, n adjacent electrodes form a group. The metal electrodes in each group are numbered 1-n. The electrodes in 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.

3. The ion deflection module adapted to traveling wave ion mobility without DC protection according to claim 2, characterized in that, A traveling wave voltage signal is applied to each electrode group of the traveling wave separation electrode. The traveling wave voltage signal is a unipolar pulsed DC voltage signal with a fixed phase delay, which causes the traveling wave potential to propagate continuously along the ion transport direction.

4. The ion deflection module adapted to traveling wave ion mobility without DC protection according to claim 1, characterized in that, A traveling wave voltage signal is a periodically changing voltage signal, and its waveform can be a sine wave, square wave, triangular wave, or chop signal.

5. The ion deflection module adapted to traveling wave ion mobility without DC protection according to claim 1, characterized in that, The radio frequency confinement electrode consists of a set of long, strip-shaped rod electrodes that are geometrically symmetrical in space, and the electrodes are insulated from each other and independent.

6. The ion deflection module adapted to traveling wave ion mobility without DC protection according to claim 1, characterized in that, The radio frequency voltage applied to the radio frequency confinement electrode is an alternating radio frequency voltage with a fixed amplitude and a frequency on the order of megahertz; the radio frequency voltage signals applied to adjacent or opposite electrodes are out of phase, thereby forming a radial effective potential well in the ion transport channel and achieving stable confinement of ions.

7. The ion deflection module for adapting to traveling wave ion mobility without DC protection according to claim 6, characterized in that, A DC bias voltage is superimposed on the radio frequency signal to adjust the ion transport conditions.

8. The ion deflection module adapted to traveling wave ion mobility without DC protection according to claim 1, characterized in that, The cross-section of the hollow ion transport channel is circular, rectangular, hexagonal, or octagonal.

9. The ion deflection module adapted to traveling wave ion mobility without DC protection according to claim 1, characterized in that, The degree of ion separation and throughput can be adjusted by modifying the wave height, wave velocity, and waveform phase difference of the traveling wave voltage signal.

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