A photoionization ring ion trap device and a method for detecting positive and negative ions.

Abstract

This invention provides a photoionization ring ion trap device and a method for detecting positive and negative ions. The device comprises a central ring column electrode, an outer ring column electrode, a mesh electrode, an ionization source, and detectors. The ionization source irradiates the ring ion trap to generate positive and negative ions. A voltage is applied to the outer and central ring column electrodes to form a radial electric field, achieving radial ion separation. The mesh electrode has pores, allowing ion emission and electric field penetration, and a resonant excitation voltage can be applied during the analysis phase. The detectors on both sides are connected to negative and positive high voltages respectively, forming an electric field to achieve axial ion separation. Ions are attracted to the corresponding detectors according to their positive and negative charges, enabling simultaneous detection of positive and negative ions. This device overcomes the limitation of traditional ion traps that can only detect a single ion type, improving detection efficiency.

Description

Technical Field

[0001] This invention relates to ion trap mass spectrometers, and more particularly to a photoionization ring ion trap device and a method for detecting positive and negative ions. Background Technology

[0002] Mass spectrometry (MS) is an analytical tool used to analyze the composition of substances and determine their molecular mass. It works by ionizing a sample into charged particles, then separating and detecting these ions based on their mass-to-charge ratio, thus obtaining a mass spectrum.

[0003] The core structure of a toroidal ion trap is a ring-shaped or toroidal electric field region. Ions are bound by the electric field within this region and move along a ring-shaped path, thus providing a large ion storage space. By precisely controlling the electric field parameters within the toroidal ion trap, the trajectory of the ions can be manipulated.

[0004] Ultraviolet lamp ionization sources typically utilize the photoelectric effect to generate positive ions. Obtaining positive and negative ion information of sample molecules is more conducive to analyzing the composition of analytes and meeting the application requirements for the detection of complex substances.

[0005] Applying a high voltage to the surface of a large-area ion detector can create a flat electric field. For example, microchannel plates (MCPs) require a high voltage to be applied to their surface during operation, which creates a flat electric field.

[0006] Existing ionization sources typically produce only one type of ion (positive or negative), and ion traps can only analyze a single type of ion.

[0007] It should be noted that the information disclosed in the background section above is only for understanding the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0008] The main objective of this invention is to solve the problems existing in the above-mentioned background technology and to provide a photoionization ring ion trap device and a method for detecting positive and negative ions.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A photoionization ring ion trap device, comprising:

[0011] A central annular columnar electrode, an outer annular columnar electrode, and two mesh electrodes together form an annular ion trap, within which ions are captured and stored.

[0012] An ionization source is irradiated into a ring-shaped ion trap, and the molecules of the sample to be tested are ionized through the photoelectric effect to generate positive ions and electrons. At the same time, the highly electronegative compound to be tested absorbs electrons to generate negative ions, thus achieving the simultaneous generation of positive and negative ions.

[0013] The outer annular column electrode is arranged around the central annular column electrode. The outer annular column electrode and the central annular column electrode cooperate to apply voltage, forming a radial electric field of the ion trap, thereby realizing radial separation of ions.

[0014] The two mesh electrodes are located on the axial outer sides of the central and outer ring-shaped electrodes, respectively, and have multiple pores for ion emission and penetration of external electric fields, and can apply resonant excitation voltage during the scanning analysis stage.

[0015] Two detectors are located on opposite sides of the annular ion trap and connected to negative and positive high voltages, respectively. The electric field formed by these detectors passes through the mesh electrodes to achieve axial separation of positive and negative ions. Based on the charge of the ions, positive and negative ions are attracted to the corresponding detectors, thus enabling simultaneous detection of positive and negative ions.

[0016] Furthermore, during the ion capture and cooling phases, the central and outer ring-shaped electrodes are subjected to high-frequency sinusoidal voltages of the same amplitude and phase, and coupled with a DC voltage of lower amplitude to form a potential difference, thereby achieving ion capture and radial separation. During the scanning analysis phase, the amplitude of the high-frequency sinusoidal voltage increases linearly with time on both the central and outer ring-shaped electrodes. During the ion capture and cooling phases, the two mesh electrodes are connected to a 0V potential, allowing the electric field formed by the detector to pass through, thereby influencing the ion distribution within the ion trap and achieving axial ion separation. During the scanning analysis phase, the two mesh electrodes are also subjected to high-frequency sinusoidal voltages of the same amplitude but opposite phase as resonant excitation voltages, causing the positive and negative ions in the ion trap to resonate and be excited out of the ion trap in order of increasing absolute mass-to-charge ratio.

[0017] Furthermore, the ionization source is an ultraviolet lamp.

[0018] A method for detecting positive and negative ions, using the aforementioned photoionization ring ion trap device to detect positive and negative ions.

[0019] Furthermore, the method includes:

[0020] Ion capture and cooling stage: The central and outer annular electrodes are subjected to high-frequency sinusoidal voltages of the same amplitude and phase, and coupled with a DC voltage of lower amplitude than the high-frequency sinusoidal voltage to form a potential difference, thereby achieving ion capture and radial separation; the two mesh electrodes are connected to a 0V potential; the two detectors are connected to a negative high voltage and a positive high voltage, respectively, and the two mesh electrodes allow the electric field formed by the two detectors to pass through, thereby affecting the ion distribution within the ion trap and achieving axial ion separation;

[0021] Scanning and analysis phase: High-frequency sinusoidal voltages with the same amplitude and phase are applied to the central and outer ring-shaped electrodes, with the amplitude increasing linearly with time, and coupled with a DC voltage with an amplitude lower than the high-frequency sinusoidal voltage; High-frequency sinusoidal voltages with the same amplitude but opposite phase are applied to the two mesh electrodes as resonant excitation voltages, so that the positive and negative ions in the ion trap are resonantly excited out of the ion trap in order of increasing absolute mass-to-charge ratio; The two detectors are connected to negative and positive high voltages respectively, and attract positive and negative ions through the pores of the corresponding mesh electrodes to the corresponding detectors according to the positive and negative charges of the ions, so as to realize the simultaneous detection of positive and negative ions.

[0022] The method further includes:

[0023] Ion removal stage: After a complete scan is completed, the voltage on the central annular electrode, the outer annular electrode, and the two mesh electrodes is unloaded, and the ions are released from the trap.

[0024] The present invention has the following beneficial effects:

[0025] This invention provides a device and method for the simultaneous separation and detection of positive and negative ions in an ionized ring ion trap. It overcomes the limitation of traditional ion traps that can only detect a single type of ion (such as positive or negative ions) during the detection process, and realizes the simultaneous separation and detection of positive and negative ions. It enables comprehensive and efficient detection of ions after macromolecular cleavage or ion reactions, thereby improving ion detection efficiency.

[0026] Other beneficial effects of the embodiments of the present invention will be further described below. Attached Figure Description

[0027] Figure 1 This is a three-dimensional view of the annular ion trap and detection device according to an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of positive and negative ion separation in the annular ion trap and detection device according to an embodiment of the present invention, wherein the black spheres are positive ion clouds and the gray spheres are negative ion clouds;

[0029] Figure 3This is a schematic diagram of ion emission from a ring ion trap according to an embodiment of the present invention, wherein positive and negative ions are affected by the electric field and can only reach the detector on one side.

[0030] Figure 4 This is a timing diagram of the voltage applied to each electrode of the annular ion trap according to an embodiment of the present invention.

[0031] Figure labels: 1 is the central ring-shaped electrode, 2 is the outer ring-shaped electrode, 3 and 4 are the mesh electrodes, 5 and 6 are the detectors located on both sides of the ion trap, and 7 is the ultraviolet lamp. Detailed Implementation

[0032] The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary and not intended to limit the scope and application of the present invention.

[0033] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component. Furthermore, a connection can be used for fixing, coupling, or communication.

[0034] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0036] See Figures 1 to 3This invention provides a photoionization ring ion trap device for simultaneous detection of positive and negative ions. It includes: a central ring electrode 1, an outer ring electrode 2, and two mesh electrodes 3 and 4, forming a ring ion trap to capture and store ions; an ionization source, such as an ultraviolet lamp 7, incident ultraviolet light into the ring ion trap at a set angle, ionizing the sample molecules to generate positive ions and electrons through the photoelectric effect, thereby simultaneously generating negative ions; the outer ring electrode 2 is arranged around the central ring electrode 1, and a voltage is applied to the outer ring electrode 2 in conjunction with the central ring electrode 1 to jointly... A radial electric field is formed in the ion trap to achieve ion capture and radial separation. The two mesh electrodes 3 and 4 are located on the axial outer sides of the central annular electrode 1 and the outer annular electrode 2, respectively. They have multiple pores for ion emission and penetration of the external electric field, and can apply a resonant excitation voltage during the scanning analysis stage. The two detectors 5 and 6 are located on both sides of the annular ion trap and are connected to negative and positive high voltages, respectively. The electric field formed passes through the mesh electrodes 3 and 4 to achieve axial separation of positive and negative ions. According to the positive and negative charges of the ions, positive and negative ions are attracted to the corresponding detectors 5 and 6, respectively, to achieve simultaneous detection of positive and negative ions.

[0037] See Figure 4 In a preferred embodiment, the central annular electrode 1 and the outer annular electrode 2 are subjected to high-frequency sinusoidal voltages of the same amplitude and phase during the ion capture and cooling phase, and coupled with a DC voltage of lower amplitude than the high-frequency sinusoidal voltage to form a potential difference, thereby achieving ion capture and radial separation. During the scanning analysis phase, the amplitude of the high-frequency sinusoidal voltage increases linearly with time for the central annular electrode 1 and the outer annular electrode 2. During the ion capture and cooling phase, the two mesh electrodes 3 and 4 are connected to a 0V potential, and the electric field formed by the detectors 5 and 6 is allowed to pass through, thereby affecting the ion distribution in the ion trap and achieving axial separation of ions. During the scanning analysis phase, the two mesh electrodes 3 and 4 are also subjected to high-frequency sinusoidal voltages of the same amplitude but opposite phase as resonant excitation voltages, so that the positive and negative ions in the ion trap are resonantly excited out of the ion trap in order of increasing absolute mass-to-charge ratio.

[0038] A method for detecting positive and negative ions, using the aforementioned photoionization ring ion trap device to detect positive and negative ions.

[0039] This invention provides a method for the simultaneous separation and detection of positive and negative ions in an ionized ring ion trap, comprising an ionization source such as an ultraviolet lamp 7, a central ring-shaped electrode 1, an outer ring-shaped electrode 2, mesh electrodes 3 and 4, and detectors 5 and 6. The ultraviolet lamp 7 is incident into the ring ion trap at a specific angle, causing the sample molecules to simultaneously generate positive and negative ions within the trap. Applying a potential difference to the ring-shaped electrode allows the positive and negative ions to be separated radially within the ion trap; simultaneously, positive and negative high voltages are applied to the surfaces of detectors 5 and 6 on both sides of the ion trap, and the resulting electric field passes through the mesh electrodes 3 and 4, causing the positive and negative ions to separate axially within the trap. After separation, a high-frequency sinusoidal voltage with a phase difference of 180° is applied to the mesh electrodes 3 and 4 on both sides, allowing the positive and negative ions to exit the trap simultaneously in different directions at the same time, achieving simultaneous detection of positive and negative ions.

[0040] An ultraviolet lamp ionization source is incident into a ring ion trap at a certain angle. Sample molecules or dopant molecules generate positive ions and electrons in the ring ion trap based on the photoelectric effect. At the same time, the highly electronegative analyte absorbs electrons to generate negative ions, thus achieving the simultaneous generation of positive and negative ions.

[0041] A DC voltage is coupled during ion capture and cooling, and the resulting potential difference causes positive and negative ions to separate radially.

[0042] Detectors 5 and 6 are located at both ends of the emission direction of the annular ion trap. The electric field formed can control the distribution of positive and negative ions in the ion trap through the mesh electrodes 3 and 4, and enable the detection of corresponding ions after they are emitted from the trap.

[0043] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0044] Traditional three-dimensional or linear ion traps can only analyze one type of ion at a time, namely positive or negative ions, and cannot simultaneously detect and separate positive and negative ions. This invention provides a photoionization ring ion trap device that can achieve the storage, separation, and detection of positive and negative ions by applying different voltage timing signals to the various electrodes of the ring ion trap and the dual detectors.

[0045] In this invention, the central annular column electrode 1, the outer annular column electrode 2, and the mesh electrodes 3 and 4 form an annular ion trap. The electric field formed by the potential difference between the central annular column electrode 1 and the outer annular column electrode 2 and between the detectors 5 and 6 located on both sides of the ion trap enables the separation of positive and negative ions along the radial and axial directions.

[0046] The specific working process of the ion trap and the voltage application method are as follows:

[0047] Phase 1: Capture and Cooling Phase: The ultraviolet ionization source is always on, continuously generating positive and negative ions in the ion trap. (See also...) Figure 2 A high-frequency alternating current (RF) voltage with the same amplitude and phase is applied to the central annular column electrode 1 and the outer annular column electrode 2, and ions are captured and stored in the annular ion trap. Simultaneously, a constant direct current (DC) voltage is coupled to the central annular column electrode 1 and the outer annular column electrode 2, forming a mesh-like structure. Electrodes 3 and 4 are connected to a 0V potential. This is due to the potential difference between the central ring electrode 1 and the outer ring electrode 2. Due to the influence of the electric field, positive and negative ions are separated radially along the ion trap. A negative high voltage is applied to the surface of detector 5, and a positive high voltage is applied to the surface of detector 6. A small portion of the electric field formed between detectors 5 and 6 passes through the mesh electrodes 3 and 4 into the ion trap, causing positive and negative ions to separate axially along the ion trap.

[0048] Phase Two: Scanning Analysis Phase: A high-frequency sinusoidal voltage (RF) is applied to the central annular electrode 1 and the outer annular electrode 2. The frequency is the same as in Phase One, but the amplitude increases linearly (frequency sweep). Similar to Phase One, a DC voltage with an amplitude much lower than RF is simultaneously coupled to the central annular electrode 1 and the outer annular electrode 2, creating a potential difference between them and maintaining the separation of positive and negative ions radially along the ion trap. High-frequency sinusoidal voltages (AC) with the same amplitude but opposite phase are applied to the mesh electrodes 3 and 4 as resonant excitation voltages. Positive and negative ions in the ion trap are resonantly excited out of the trap in order of increasing absolute mass-to-charge ratio. Similar to Phase One, detectors are located on both sides of the annular ion trap; detector 5's electrode is connected to a negative high voltage, and detector 6's electrode is connected to a positive high voltage. (See also...) Figure 3 Among the charged ions leaving the ring ion trap, positively charged ions exiting from the mesh electrode aperture closer to detector 6 will be repelled by the electric field and unable to reach the detector; however, if they exit from the mesh electrode aperture closer to detector 5, the positive ions will collide with the detector along the electric field direction, generating a signal. Similarly, negatively charged ions exiting from the mesh electrode aperture closer to detector 5 will be repelled by the electric field and unable to reach the detector; however, if they exit from the mesh electrode aperture closer to detector 6, the positive ions will collide with the detector along the electric field direction, generating a signal. This will result in separate responses to positive and negative ions on the two detectors.

[0049] Third stage: Ion removal stage: After completing a full scan, the voltage on the central ring column electrode 1, outer ring column electrode 2, and mesh electrodes 3 and 4 is unloaded, and the ions will lose their binding and be removed from the trap.

[0050] In this example, the mesh electrodes 3 and 4 are mesh-like, allowing ions to exit through their pores. Simultaneously, they shield most of the electric field generated by detectors 5 and 6, allowing only a small portion to pass through and affect the distribution of positive and negative ions.

[0051] The present invention is not limited to the orbital ion trap shown in the figure, but can also be other shapes of polygonal traps or chamfered circular traps, etc.; the shape of the ion trap electrode is not limited, and the electrode can be in the form of hyperbola, plate, cylinder, arc or triangle, etc.; the position, length, width and shape of the electrode slit are also not limited.

[0052] This invention overcomes the limitation of ion traps, which can only detect a single type of ion (such as positive or negative ions), and enables comprehensive and efficient detection of ions after macromolecular fragmentation or ion reactions, thereby improving detection efficiency.

[0053] The above description provides a further detailed explanation of the present invention in conjunction with specific / preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A photoionization ring ion trap device, characterized in that, include: A central annular columnar electrode, an outer annular columnar electrode, and two mesh electrodes together form an annular ion trap, within which ions are captured and stored. An ionization source is used to irradiate the ring ion trap, and the photoelectric effect is used to ionize the molecules of the sample to be tested to generate positive ions and electrons. At the same time, the highly electronegative sample compound absorbs electrons to generate negative ions. The outer annular column electrode is arranged around the central annular column electrode. The outer annular column electrode and the central annular column electrode cooperate to apply voltage, forming a radial electric field of the ion trap, thereby realizing radial separation of ions. The two mesh electrodes are located on the axial outer sides of the central and outer ring-shaped electrodes, respectively, and have multiple pores for ion emission and penetration of external electric fields, and can apply resonant excitation voltage during the scanning analysis stage. Two detectors are located on opposite sides of the annular ion trap and connected to negative and positive high voltages, respectively. The electric field formed by these detectors passes through the mesh electrodes to achieve axial separation of positive and negative ions. Based on the charge of the ions, positive and negative ions are attracted to the corresponding detectors, thus enabling simultaneous detection of positive and negative ions.

2. The photoionization ring ion trap device as described in claim 1, characterized in that, The central and outer annular electrodes are subjected to high-frequency sinusoidal voltages of the same amplitude and phase during the ion capture and cooling phases, and are coupled with DC voltages of lower amplitude than the high-frequency sinusoidal voltages to form a potential difference, thereby achieving ion capture and radial separation. During the scanning analysis phase, the amplitude of the high-frequency sinusoidal voltage is linearly increased with time by the central and outer annular electrodes. The two mesh electrodes are connected to a 0V potential during the ion capture and cooling stage, allowing the electric field formed by the detector to pass through, thereby affecting the ion distribution in the ion trap and achieving axial separation of ions. During the scanning analysis stage, the two mesh electrodes are also applied with high-frequency sinusoidal voltages of the same amplitude but opposite phase as resonant excitation voltages, so that the positive and negative ions in the ion trap are resonantly excited out of the ion trap in order of increasing absolute mass-to-charge ratio.

3. The photoionization ring ion trap device as described in claim 1 or 2, characterized in that, The ionization source is an ultraviolet lamp.

4. A method for detecting positive and negative ions, characterized in that, Positive and negative ion detection is performed using the photoionization ring ion trap device as described in any one of claims 1 to 3.

5. The positive and negative ion detection method as described in claim 4, characterized in that, include: Ion capture and cooling stage: The central and outer annular electrodes are subjected to high-frequency sinusoidal voltages of the same amplitude and phase, and coupled with a DC voltage of lower amplitude than the high-frequency sinusoidal voltage to form a potential difference, thereby achieving ion capture and radial separation; the two mesh electrodes are connected to a 0V potential; the two detectors are connected to a negative high voltage and a positive high voltage, respectively, and the two mesh electrodes allow the electric field formed by the two detectors to pass through, thereby affecting the ion distribution within the ion trap and achieving axial ion separation; Scanning and analysis phase: High-frequency sinusoidal voltages with the same amplitude and phase are applied to the central and outer ring-shaped electrodes, with the amplitude increasing linearly with time, and coupled with a DC voltage with an amplitude lower than the high-frequency sinusoidal voltage; High-frequency sinusoidal voltages with the same amplitude but opposite phase are applied to the two mesh electrodes as resonant excitation voltages, so that the positive and negative ions in the ion trap are resonantly excited out of the ion trap in order of increasing absolute mass-to-charge ratio; The two detectors are connected to negative and positive high voltages respectively, and attract positive and negative ions through the pores of the corresponding mesh electrodes to the corresponding detectors according to the positive and negative charges of the ions, so as to realize the simultaneous detection of positive and negative ions.

6. The positive and negative ion detection method as described in claim 5, characterized in that, Also includes: Ion removal stage: After a complete scan is completed, the voltage on the central annular electrode, the outer annular electrode, and the two mesh electrodes is unloaded, and the ions are released from the trap.

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