The ionization source and method in sequence

Abstract

This invention provides a sequential ionization source and method. The sequential ionization source includes a first set of magnets and a first electron source, the first electron source being disposed in a first magnetic field formed by the first set of magnets. It also includes: a cavity having an ion outlet, internally divided into sequentially connected multi-stage chambers by multiple isolators, with a pump connected to the interior of the cavity; the isolators having through-holes allowing ions to pass through, the arrangement direction of the through-holes on the multiple isolators forming an acute angle or a right angle with the direction of the first magnetic field; the first electron source being disposed in a first-stage chamber; a second electron source being disposed in a second-stage chamber and situated in a second magnetic field formed by a second set of magnets, the arrangement direction of the through-holes on the multiple isolators forming an acute angle or a right angle with the direction of the first magnetic field; an ion transport device being disposed within the cavity; the angle between the velocity direction of the sample entering the first-stage chamber from the sample inlet and the arrangement direction is zero or an acute angle. This invention has the advantage of high ionization efficiency.

Description

Technical Field

[0001] This invention relates to ionization, and more particularly to sequential ionization sources and methods. Background Technology

[0002] A mass spectrometry system typically includes an ion source for ionization, a mass analyzer for separating ions with different mass-to-charge ratios, and an ion detector for detecting ion signals. The mass analyzer is used to screen and perform qualitative and quantitative measurements of target substances.

[0003] Ion generation is a crucial component of mass spectrometry. In gas chromatography-tandem mass spectrometry (GC-MS), an electron ionization (EI) source is typically used to ionize the sample. The most important component of the electron ionization source is the filament. When the filament is heated, it emits electrons. These electrons propel themselves spirally under the influence of an electromagnetic field, and sample molecules are introduced into the chamber along a path that intersects with the electron beam. Ionization of sample molecules occurs in the region where the sample molecules and filament electrons intersect, and the primary mode of ionization can be described as: M + e⁻ - →M* + + 2e - Where M represents the sample molecule, e - M* represents electrons. + This indicates the generated molecular ion. In other words, the sample loses an electron under the influence of electrons, thus generating a positive ion. Improving the ionization efficiency of EI ion sources is currently one of the key focuses for instrument manufacturers. Summary of the Invention

[0004] To address the shortcomings of the existing technical solutions, the present invention provides a sequential ionization source.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] The sequential ionization source includes a first set of magnets and a first electron source, wherein the first electron source is disposed in a first magnetic field formed by the first set of magnets; the sequential ionization source further includes:

[0007] The cavity and pump are provided. The cavity has an ion outlet and is internally divided into multiple interconnected multi-stage chambers by multiple isolators. The pump is connected to the interior of the cavity. The isolators have through holes that allow ions to pass through. The arrangement direction of the through holes on the multiple isolators is at an acute angle or a right angle with the direction of the first magnetic field. The first electron source is disposed in the first-stage chamber.

[0008] The second electron source and the second set of magnets are disposed in the second stage chamber and are in the second magnetic field formed by the second set of magnets;

[0009] An ion transport device, wherein the ion transport device is disposed within the cavity;

[0010] The angle between the velocity direction of the sample entering the first-stage chamber from the sample inlet and the arrangement direction is zero or acute.

[0011] The present invention also aims to provide a sequential ionization method, which is achieved through the following technical solution:

[0012] The sequential ionization method is as follows:

[0013] The sample discharged from the sample inlet enters the multi-stage chambers in the cavity in sequence. The interior of the cavity is divided into multi-stage chambers that are connected in sequence by multiple isolation components. The angle between the sample transmission direction and the arrangement direction of the through holes on the multiple isolation components is zero or an acute angle. The pump extracts the gas in the cavity.

[0014] In each chamber, electrons emitted by the electron source advance under the influence of the magnetic field. The angle between the direction of advancement and the arrangement direction is a right angle or an acute angle. The sample gas collides with the electrons and is ionized.

[0015] Ions pass through the chambers sequentially under the action of the ion transport device and finally exit from the ion outlet.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] 1. High ionization efficiency;

[0018] The system is designed with multiple chambers connected in series and the sample entry direction and ion transport direction are planned. With the sample transported in the same direction, the sample enters each chamber sequentially and is ionized by the electrons in each chamber, thus realizing the sequential transfer of ions and significantly improving the ionization efficiency.

[0019] 2. High ion transport efficiency;

[0020] The pump connects to the cavity, such as the last stage chamber, so that the vacuum level in each of the series-connected chambers increases, ensuring ion transport efficiency. Attached Figure Description

[0021] The disclosure of this invention will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are merely illustrative of the technical solutions of this invention and are not intended to limit the scope of protection of this invention. In the drawings:

[0022] Figure 1 This is a schematic flowchart of the sequential ionization method according to an embodiment of the present invention. Detailed Implementation

[0023] Figure 1 The following description illustrates optional embodiments of the invention to teach those skilled in the art how to implement and reproduce the invention. Some conventional aspects have been simplified or omitted for the purpose of teaching the invention. Those skilled in the art should understand that variations or substitutions derived from these embodiments will be within the scope of the invention. Those skilled in the art should understand that the following features can be combined in various ways to form multiple variations of the invention. Therefore, the invention is not limited to the following optional embodiments, but is defined only by the claims and their equivalents.

[0024] Example 1

[0025] The sequential ionization source of this invention includes:

[0026] A first set of magnets and a first electron source, wherein the first electron source is disposed in a first magnetic field formed by the first set of magnets;

[0027] The system includes a cavity and a pump. The cavity has an ion outlet and is internally divided into multiple interconnected multi-stage chambers by multiple isolators. The pump connects to the interior of the cavity, such as to the last stage chamber. The isolators have through holes that allow ions to pass through, and the arrangement of the through holes on the multiple isolators is at an acute angle or a right angle to the direction of the first magnetic field. The first electron source is disposed in the first stage chamber.

[0028] The second electron source and the second set of magnets are disposed in the second stage chamber and are in the second magnetic field formed by the second set of magnets;

[0029] An ion transport device, wherein the ion transport device is disposed within the cavity;

[0030] The angle between the velocity direction of the sample entering the first-stage chamber from the sample inlet and the arrangement direction is zero or acute.

[0031] To further improve ionization and ion transport efficiency, the central axes of the sample inlet, the through holes on the multiple isolation components, and the ion outlet are collinear.

[0032] To improve the accuracy of subsequent analysis, the chromatographic column is further fixed on the cavity, and the output end of the chromatographic column serves as the sample inlet and is located in the first-stage cavity.

[0033] To further improve ion transport efficiency, the ion transport device includes a power supply and multiple transport electrodes, the transport electrodes being disposed on the isolation member, and the output of the power supply being connected to the multiple transport electrodes.

[0034] To further reduce structural complexity, the first set of magnets and the second set of magnets are shared.

[0035] Figure 1 A flowchart illustrating the sequential ionization method of an embodiment of the present invention is given, as follows: Figure 1 As shown, the sequential ionization method is as follows:

[0036] The sample discharged from the sample inlet enters the multi-stage chambers in the cavity in sequence. The interior of the cavity is divided into multi-stage chambers that are connected in sequence by multiple isolation components. The angle between the sample transmission direction and the arrangement direction of the through holes on the multiple isolation components is zero or an acute angle. The pump extracts the gas in the cavity.

[0037] In each chamber, electrons emitted by the electron source advance under the influence of a magnetic field. The angle between the direction of advancement and the arrangement direction is a right angle or an acute angle. The sample gas collides with the electrons and is ionized. An electron detection device is placed opposite the electrons emitted by the electron source for the evaluation of the filament current.

[0038] Ions pass through the chambers sequentially under the action of the ion transport device and finally exit from the ion outlet.

[0039] To further improve ionization and ion transport efficiency, the central axes of the sample inlet, the through holes on the multiple isolation components, and the ion outlet are collinear.

[0040] To improve the accuracy of subsequent analysis, the chromatographic column is further fixed on the cavity, and the output end of the chromatographic column serves as the sample inlet and is located in the first-stage cavity.

[0041] To further improve ion transport efficiency, the ion transport device includes a power supply and multiple transport electrodes, the transport electrodes being disposed on the isolation member, and the output of the power supply being connected to the multiple transport electrodes.

[0042] To further reduce structural complexity, magnets are shared across all chamber levels.

[0043] Example 2

[0044] An example of the application of the sequential ionization source and method according to Embodiment 1 of the present invention in mass spectrometry analysis.

[0045] In this application example, the chamber is divided into four levels by three separators. The last level chamber has an ion outlet, and an ion extraction electrode is installed downstream of the ion outlet. The chromatographic column is fixed to the first level chamber and extends into it. Each level chamber has an electron source, and the magnets of each level chamber are shared. Ion transport electrodes are installed on the three separators: the first ion transport electrode to the third ion transport electrode, and the fourth ion transport electrode is installed at the ion outlet of the last level chamber. The central axis of the column outlet, the central axis of the through holes on each ion transport electrode, and the central axis of the ion outlet are collinear and perpendicular to the direction of the magnetic field formed by the magnet. That is, the direction of sample gas entering the chamber is the same as the ion transport direction and perpendicular to the electron transport direction. The pump is connected to the last level chamber to increase the vacuum level in each level chamber. Along the ion transport direction, the vacuum level in each level chamber gradually increases.

[0046] An electrode is installed at the sample gas inlet in the first-stage chamber; that is, this electrode, the first ion transport electrode to the fourth ion transport electrode, and the extraction electrode are installed sequentially. The electrode at the sample gas inlet is set to positive voltage. The voltage of the first ion transport electrode is between -5V and +5V. The second to fourth ion transport electrodes and the extraction electrode are all negatively charged. It is required that the voltage of the electrode at the sample gas inlet > the voltage of the first ion transport electrode > the voltage of the second ion transport electrode, the voltage of the first ion transport electrode > the voltage of the third ion transport electrode > the voltage of the second ion transport electrode, the voltage of the second ion transport electrode > the voltage of the fourth ion transport electrode, and the voltage of the first ion transport electrode > the voltage of the extraction electrode > the voltage of the fourth ion transport electrode.

[0047] Figure 1 A flowchart illustrating the sequential ionization method of an embodiment of the present invention is given, as follows: Figure 1 As shown, the sequential ionization method (i.e., the working method of the sequential ionization source in this embodiment) is as follows:

[0048] The sample discharged from the sample inlet enters the four-stage chamber in the cavity in sequence. The angle between the sample transmission direction and the arrangement direction of the through holes on the multiple isolation components is zero. The pump extracts the gas in the cavity, so that the vacuum degree of the series-connected chambers gradually increases.

[0049] In each chamber, electrons emitted by the electron source advance under the influence of the magnetic field, and the angle between the direction of advancement and the arrangement direction is a right angle. The sample gas collides with the electrons and is ionized.

[0050] The overall potential of the ion transport device decreases. Under the action of the ion transport device, ions pass through the chambers in sequence and are focused, and finally exit from the ion outlet.

[0051] In this embodiment, the angle between the sample transmission direction and the arrangement direction of the through holes on the multiple isolators is zero, although there can be some deviation, such as 1 degree or 2 degrees; the angle between the forward direction and the arrangement direction is a right angle, or it can be an acute angle close to a right angle, such as 89 degrees or 89.5 degrees, but these changes in angle will lead to a decrease in ionization efficiency.

Claims

1. A sequential migration ion source comprising a first set of magnets and a first electron source disposed in a first magnetic field formed by the first set of magnets; characterized by, The ion source further comprises: a cavity having an ion outlet, an interior divided into multiple stages of chambers by multiple partitions, and a pump communicating with the interior of the cavity; the partitions have through holes allowing ions to pass through, and the arrangement direction of the through holes on the multiple partitions is an acute angle or a right angle with the direction of the first magnetic field; the first electron source is arranged in the first stage of chamber; a second electron source arranged in the second stage of chamber and in a second magnetic field formed by a second set of magnets; an ion transmission device arranged in the cavity; a sample inlet, and the included angle between the velocity direction of the sample entering the first stage of chamber from the sample inlet and the arrangement direction is zero or acute.

2. The sequential migration ionization source of claim 1, wherein, The central axes of the sample inlet, the through holes on the multiple partitions, and the ion outlet are collinear.

3. The sequential migration ionization source of claim 1, wherein, A chromatographic column is fixed on the cavity, and the output end of the chromatographic column serves as the sample inlet and is in the first stage of chamber.

4. The sequential migration ionization source of claim 1, wherein, The ion transmission device comprises a power supply and multiple transmission electrodes arranged on the partitions, and the output of the power supply is connected to the multiple transmission electrodes.

5. The sequential migration ionization source of claim 1, wherein, The first set of magnets and the second set of magnets are shared.

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