阅读说明：本技术 复合离子源及其使用方法和质谱仪 (Composite ion source, method of using the same, and mass spectrometer ) 是由 岑延相 吴曼曼 黄豆 李辉 邓伟 于 2019-04-16 设计创作，主要内容包括：本发明涉及一种复合离子源及其使用方法和含有该复合离子源的质谱仪。该复合离子源包括外壳、电离室、样品引入管、电子产生装置、磁场产生装置、单光子产生装置、推斥极、离子透镜组件及加热组件。该复合离子源将电子轰击源和单光子电离源整合在一个结构中,在样品检测时,可以根据样品的类型进行选择,选用电子轰击源或者单光子电离源,也可以在不清楚样品组成的情况下采用单光子电离源模式进行定性检测分析,并采用电子轰击源进行定量分析。该复合离子源较之传统的复合离子源,结构简单,易于安装和维护,有利于商品化和长期稳定使用。(The invention relates to a composite ion source, a using method thereof and a mass spectrometer containing the composite ion source. The compound ion source comprises a shell, an ionization chamber, a sample introducing tube, an electron generating device, a magnetic field generating device, a single photon generating device, a repulsion electrode, an ion lens assembly and a heating assembly. The composite ion source integrates an electron bombardment source and a single photon ionization source into a structure, can be selected according to the type of a sample during sample detection, selects the electron bombardment source or the single photon ionization source, can perform qualitative detection analysis in a single photon ionization source mode under the condition that the composition of the sample is not clear, and performs quantitative analysis by using the electron bombardment source. Compared with the traditional composite ion source, the composite ion source has the advantages of simple structure, easy installation and maintenance, and is favorable for commercialization and long-term stable use.)

1. A composite ion source is characterized by comprising a shell, an ionization chamber, a sample introducing tube, an electron generating device, a magnetic field generating device, a single photon generating device, a repulsion electrode, an ion lens assembly and a heating assembly;

the shell is provided with an accommodating cavity, and a sample introducing hole communicated with the accommodating cavity is formed in the shell; the ionization chamber and the repulsion electrode are arranged in the accommodating cavity, and the ionization chamber is provided with a photon inlet, a sample inlet, an electron inlet and an ion outlet; the sample introduction tube passes through the sample introduction hole and interfaces with the sample inlet; the electron generating device is arranged on the shell and corresponds to the electron inlet; the magnetic field generating device is used for generating a magnetic field so that electrons generated by the electron generating device are incident into the ionization chamber through the electron inlet; the repulsion electrode and the ion lens component are respectively arranged corresponding to the photon inlet and the ion outlet; the single photon generating device is arranged at the front end of the repulsion electrode so as to lead the generated photons into the ionization chamber through the photon inlet by the repulsion electrode; the ion lens assembly is used for leading out an ion beam from the ion outlet; the heating component is arranged on the shell to control the temperature of the ionization chamber.

2. The composite ion source of claim 1, wherein the repeller has a photon through hole, the photon through hole of the repeller being disposed in correspondence with the photon entrance; and/or

The ionization chamber is a hollow cylindrical structure with openings at two ends, wherein the opening at one end is the photon inlet, the opening at the other end is the ion outlet, and the sample inlet and the electron inlet are respectively arranged on the wall of the ionization chamber; and/or

The ionization chamber, the single photon generating device, the repulsion electrode and the ion lens component are arranged in a common central axis.

3. The composite ion source of claim 1, wherein the direction of entry of the sample from the sample inlet intersects the direction of incidence of the electrons from the electron inlet on a central axis of the ionization chamber.

4. The composite ion source of claim 1, wherein there are two of said electron inlets, said two electron inlets being oppositely disposed;

correspondingly, the number of the electron generating devices is two, and the two electron generating devices respectively correspond to the two electron inlets.

5. The compound ion source of claim 4, wherein the magnetic field generating means comprises two permanent magnets, the two permanent magnets are mounted at positions corresponding to the two electron generating means, respectively, and the magnetic poles of the two permanent magnets are arranged oppositely.

6. The composite ion source of any one of claims 1 to 5, wherein a filament of the electron generating device is made of rhenium or a rhenium-tungsten alloy.

7. The composite ion source of any of claims 1 to 5, wherein the ion lens assembly comprises an extraction electrode, a first focusing electrode, a second focusing electrode, an exit electrode, a transmission electrode and a combined electrode consisting of an upper semicircular electrode and a lower semicircular electrode which are arranged at one end of the ionization chamber, and the electrodes are arranged in a common central axis.

8. A mass spectrometer comprising a mass analyser and a source of complex ions according to any of claims 1 to 7, the source of complex ions being located at the front end of the mass analyser.

9. The mass spectrometer of claim 8, further comprising a tuning device;

the tuning device comprises a first tuning container, a first control switch, a second tuning container and a second control switch, wherein the first tuning container and the second tuning container are respectively used for containing a first tuning liquid corresponding to an electron bombardment source and a second tuning liquid corresponding to a single photon ionization source, and the first control switch and the second control switch are respectively used for controlling the first tuning container and the second tuning container to be opened or closed.

10. The use method of the composite ion source is characterized in that the composite ion source according to any one of claims 1-7 is used, two tuning liquids are independently switched according to the type of the ion source called by the composite ion source, a first tuning liquid is used for signal tuning when an electron bombardment source is tuned, and a second tuning liquid is used for tuning when a single photon ionization source is tuned.

Technical Field

The invention relates to the technical field of mass spectrometry, in particular to a composite ion source, a using method thereof and a mass spectrometer.

Background

Mass spectrometers, also known as mass spectrometers, are based on the principle that charged particles can deflect in electric and magnetic fields, and are composed by separation and detection of mass differences of atoms, molecules or molecular fragments of matter. The mass spectrometry has high speed and accurate qualitative and quantitative results, so the method is widely applied to the fields of geology, mineralogy, geochemistry, nuclear industry, material science, environmental chemistry, medical identification and sanitary detection, food chemistry, petrochemical industry and the like, and special analysis aspects of space technology, public security work and the like.

The ion source is one of the most important components of a mass spectrometer and is used for ionizing, focusing and transporting neutral molecules or atoms to a mass analyzer for mass analysis. Among them, the electron impact source (EI) is one of the most commonly used ion sources due to its simple structure, high sensitivity, and retrievability with standard spectral libraries. However, the ionization energy of the electron bombardment source is higher, generally 70eV, more ion fragments are generated, almost no molecular ions exist, and mass spectrogram analysis and molecular weight determination of a complex sample are very difficult; in contrast, a single photon ionization Source (SPI) has low energy, usually around 10.6eV, and mainly molecular ions are obtained by ionizing a sample, and substantially no fragment ions are generated, so that the molecular weight of the compound can be accurately determined. By combining EI and SPI, the molecular weight and structural information of the compound can be simultaneously measured, and the qualitative accuracy of the components is obviously improved.

Disclosure of Invention

Based on this, there is a need for a composite ion source using EI in combination with SPI, methods of using the same, and mass spectrometers containing the same.

A composite ion source comprises a shell, an ionization chamber, a sample introducing tube, an electron generating device, a magnetic field generating device, a single photon generating device, a repulsion electrode, an ion lens assembly and a heating assembly;

the shell is provided with an accommodating cavity, and a sample introducing hole communicated with the accommodating cavity is formed in the shell; the ionization chamber and the repulsion electrode are arranged in the accommodating cavity, and the ionization chamber is provided with a photon inlet, a sample inlet, an electron inlet and an ion outlet; the sample introduction tube passes through the sample introduction hole and interfaces with the sample inlet; the electron generating device is arranged on the shell and corresponds to the electron inlet; the magnetic field generating device is used for generating a magnetic field so that electrons generated by the electron generating device are incident into the ionization chamber through the electron inlet; the repulsion electrode and the ion lens component are respectively arranged corresponding to the photon inlet and the ion outlet; the single photon generating device is arranged at the front end of the repulsion electrode so as to lead the generated photons into the ionization chamber through the photon inlet by the repulsion electrode; the ion lens assembly is used for leading out an ion beam from the ion outlet; the heating component is arranged on the shell to control the temperature of the ionization chamber.

In one embodiment, the repulsion electrode is provided with a photon through hole, and the photon through hole of the repulsion electrode is arranged corresponding to the photon inlet; and/or

The ionization chamber is a hollow cylindrical structure with openings at two ends, wherein the opening at one end is the photon inlet, the opening at the other end is the ion outlet, and the sample inlet and the electron inlet are respectively arranged on the wall of the ionization chamber; and/or

The ionization chamber, the single photon generating device, the repulsion electrode and the ion lens component are arranged in a common central axis.

In one embodiment, the entrance direction of the sample entering from the sample inlet and the incidence direction of the electrons entering from the electron inlet intersect on the central axis of the ionization chamber.

In one embodiment, the number of the electron inlets is two, and the two electron inlets are oppositely arranged;

correspondingly, the number of the electron generating devices is two, and the two electron generating devices respectively correspond to the two electron inlets.

In one embodiment, the magnetic field generating device comprises two permanent magnets, the installation positions of the two permanent magnets respectively correspond to the two electron generating devices, and the magnetic poles of the two permanent magnets are arranged oppositely.

In one embodiment, the filament of the electron generating device is made of rhenium or tungsten-rhenium alloy.

In one embodiment, the ion lens assembly comprises an extraction electrode, a first focusing electrode, a second focusing electrode, an exit electrode, a transmission electrode and a combined electrode consisting of an upper semicircular electrode and a lower semicircular electrode which are arranged at one end of the ionization chamber, and the electrodes are arranged in a common central axis.

A mass spectrometer comprising a mass analyser and a complex ion source as described in any of the above embodiments, the complex ion source being located at the front end of the mass analyser.

In one embodiment, the mass spectrometer further comprises a tuning device;

the tuning device comprises a first tuning container, a first control switch, a second tuning container and a second control switch, wherein the first tuning container and the second tuning container are respectively used for containing a first tuning liquid corresponding to an electron bombardment source and a second tuning liquid corresponding to a single photon ionization source, and the first control switch and the second control switch are respectively used for controlling the first tuning container and the second tuning container to be opened or closed.

The use method of the composite ion source comprises the steps of independently switching two paths of tuning liquid according to the type of the ion source called by the composite ion source, tuning a signal by using a first tuning liquid when tuning an electron bombardment source, and tuning by using a second tuning liquid when tuning a single photon ionization source.

The composite ion source and the mass spectrometer comprising the same integrate the electron bombardment source and the single photon ionization source into one structure, can be selected according to the type of a sample during sample detection, select the electron bombardment source or the single photon ionization source, can perform qualitative detection and analysis by adopting a single photon ionization source mode under the condition that the composition of the sample is not clear, and perform quantitative analysis by adopting the electron bombardment source. After the ion source type is determined, corresponding tuning liquid can be selected for signal debugging, and finally spectrogram analysis is carried out, the whole detection and analysis process can be flexible and changeable, rich fragment peak information can be obtained by using an electron bombardment source, a stable mass spectrogram can be obtained to be matched and searched with mass spectrum image libraries such as NIST (National Institute of Standards and technology ) and the like, a molecular ion peak can be obtained by depending on a single photon ionization source, the qualitative accuracy is improved, the sensitivity of the single photon ionization source is good on the premise of not losing the high sensitivity of the electron bombardment source, and the remarkable effect is obtained in the qualitative and quantitative analysis of a complex sample.

Compared with the traditional composite ion source, the composite ion source has the advantages of simple structure, easy installation and maintenance, and is favorable for commercialization and long-term stable use.

Drawings

FIG. 1 is a schematic diagram of a composite ion source according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a tuning apparatus according to an embodiment.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

As shown in fig. 1, an embodiment of the present invention provides a compound ion source 10, which includes a housing 11, an ionization chamber 12, a sample introducing tube (not shown), an electron generating device 13, a magnetic field generating device 14, a single photon generating device 15, a repeller 16, an ion lens assembly 17, and a heating assembly (not shown).

The housing 11 has a receiving cavity 111. The housing 11 is further provided with a sample introduction hole 112 communicating with the accommodation chamber 111. The ionization chamber 12 and the repeller 16 are disposed in the housing cavity 111 of the housing 11. The ionization chamber 12 is provided with a photon inlet (not shown), a sample inlet (not shown), an electron inlet 121, and an ion outlet (not shown). The sample inlet corresponds to a sample introduction hole in the housing 11, and a sample introduction tube passes through the sample introduction hole 112 and interfaces with the sample inlet for introducing the sample into the ionization chamber 12 to complete ionization. The electron generating device 13 is disposed on the housing 11 and corresponds to the electron inlet 121. The magnetic field generating device 14 is used for generating a magnetic field to make the electrons generated by the electron generating device 13 incident into the ionization chamber 12 through the electron inlet 121. The repeller 16 and ion lens assembly 17 are disposed corresponding to the photon entrance and ion exit, respectively. The single photon generator 15 is provided at the front end of the repeller 16 so that the generated photons are introduced from the repeller 16 into the ionization chamber 12 through the photon inlet. The ion lens assembly 17 is used to extract the ion beam from the ion outlet. A heating assembly is provided on the housing 11 to control the temperature of the ionization chamber 12.

The housing 11 provides a vaculable environment for the partial structure of the composite ion source 10. The holding chamber 111 can be pumped to a higher vacuum, typically 2.0 × 10^-3Pa～5.0×10^-4Pa。

In one particular example, the ionization chamber 12 is a hollow cylindrical structure open at both ends. The ionization chamber 12 has an opening at one end, i.e., a photon inlet, and an opening at the other end, i.e., an ion outlet. The sample inlet and the electron inlet 121 are provided on the walls of the ionization chamber 12, respectively.

The repeller 16 has a photon through hole 161, and the photon through hole of the repeller 16 is disposed corresponding to the photon entrance of the ionization chamber 12. The ultraviolet photons emitted by the single photon generator 15 can enter the ionization chamber 12 through the photon through hole 161 of the repeller 16.

In a preferred example, the ionization chamber 12, the single photon generating device 15, the repeller 16 and the ion lens assembly 17 are arranged coaxially. Further preferably, the entering direction of the sample entering from the sample inlet and the incident direction of the electrons entering from the electron inlet 121 intersect on the central axis of the ionization chamber 12.

In the illustrated specific example, there are two electron inlets 121, and the two electron inlets 121 are disposed opposite to each other. Accordingly, there are two electron generating devices 13, and the two electron generating devices 13 correspond to the two electron inlets 121, respectively. The inner surface of the ionization chamber 12 is cylindrical, and by applying a potential difference between the ionization chamber 12 and the two electron generation devices 13, the electrons emitted by the two electron generation devices 13 can obtain corresponding energy.

In a specific example, the electron generating device 13 is an emitter with a filament. The material of the filament may be, but is not limited to, rhenium or rhenium-tungsten alloy. The two emitters are located outside the ionization chamber 12 and face the electron entrance 121 of the ionization chamber 12.

Further, the magnetic field generating device 14 includes two permanent magnets 141. The two permanent magnets 141 are installed at positions corresponding to the two electron generators 13, and the magnetic poles of the two permanent magnets 141 are oppositely arranged to generate a magnetic field perpendicular to the central axis of the ionization chamber 12.

The ion lens assembly 17 is used to extract the ion beam. More specifically, in one example, the ion LENS assembly 17 includes an extraction electrode 170, a first focusing electrode 171, a second focusing electrode 172, an exit electrode 173, transmission electrodes 174 and 176, and a combined electrode 175 composed of an upper semicircular electrode (LENS UP)1751 and a lower semicircular electrode (LENS DOWN)1752 disposed at one end of the ionization chamber 12. The extraction electrode 170, the first focusing electrode 171, the second focusing electrode 172, the exit electrode 173, the transmission electrode 174, the combined electrode 175, and the transmission electrode 176 are disposed in this order away from the ionization chamber 12. The center of each electrode is provided with a hole, and adjacent electrodes are insulated and installed in the shell 11 through structures such as an insulating pad. All the electrodes are arranged in a way of sharing a central axis. An upper semicircular electrode (LENS UP)1751 is located at the upper end and a lower semicircular electrode (LENS DOWN)1752 is located at the lower end for further flattening the focused ion beam for incorporation into a back-end mass analyzer.

The heating assembly comprises a heating device and a temperature measuring device which are arranged on the shell 11. The heating device is used to heat the ionization chamber 12. The temperature measuring device is used for monitoring the temperature of the ionization chamber 12 in real time. The heating device is matched with the temperature measuring device, so that the temperature of the composite ion source 10 can be independently controlled.

The present invention further provides a mass spectrometer comprising a mass analyser and a complex ion source 10 as described above. A complex ion source 10 is located at the front end of the mass analyser. The ion beam generated by the coincidence ion source 10 enters a mass analyzer for detection analysis, such as mass number and response intensity detection.

In one particular example, as shown in fig. 2, the mass spectrometer further comprises a tuning device 20.

The tuning arrangement 20 comprises a first tuning vessel 21, a first control switch 22, a second tuning vessel 23 and a second control switch 24. The first tuning vessel 21 and the second tuning vessel 23 are used for respectively containing a first tuning liquid (such as perfluorotributylamine) corresponding to an electron bombardment source and a second tuning liquid (such as methyl salicylate) corresponding to a single photon ionization source. The first control switch 22 and the second control switch 24 are used to control the opening or closing of the first tuning vessel 21 and the second tuning vessel 23, respectively, so that the first tuning fluid or the second tuning fluid can be volatilized into the ionization chamber 12 to tune the instrument signal.

When the whole mass spectrometer is combined with a gas chromatography mass spectrometer, a sample reaches the ionization chamber 12 through the sample introducing tube, electrons generated by the electron generating device 13 are accelerated to enter the ionization chamber 12 from the electron inlet 121 under the action of an electromagnetic field and obtain 70eV kinetic energy, and then the standard 70eV ionization energy is obtained. The electrons bombard the sample molecules, the obtained fragment ions also impact the molecular ions, so that the sample molecules are converted into sample ions, and finally the sample ions enter the mass analyzer through the ion lens assembly 17 to finish the detection of mass number and response intensity.

When the ultraviolet single photon ionization source is used, a sample reaches the ionization chamber 12 through the sample introducing tube, ultraviolet light emitted by the single photon generating device 15 directly enters the ionization chamber 12 through the photon through hole 161 of the repulsion electrode 16 to irradiate sample molecules, so that the sample molecules are converted into sample ions, and finally the sample ions enter the mass analyzer through the ion lens assembly 17 to finish the detection of mass number and response intensity.

Further, the invention also provides a using method of the composite ion source, and by using the composite ion source 10, the using method is that two paths of tuning liquid are independently switched according to the type of the ion source called by the composite ion source 10, a first tuning liquid is used for signal tuning when an electron bombardment source is tuned, and a second tuning liquid is used for tuning when a single photon ionization source is tuned.

Specifically, the method can be carried out according to the following steps:

the method comprises the following steps: setting a tuning device (such as the tuning device shown in fig. 2), wherein the tuning device is required to comprise a first tuning container, a first control switch, a second tuning container and a second control switch, the first tuning container and the second tuning container are respectively used for containing a first tuning liquid corresponding to an electron bombardment source and a second tuning liquid corresponding to a single photon ionization source, the first control switch and the second control switch are respectively used for controlling the opening or closing of the first tuning container and the second tuning container, and the tuning device is used for adjusting the voltage amplitude of each electrode of an ion lens assembly 17 of the composite ion source;

step two: respectively filling a first tuning container and a second tuning container with a first tuning liquid and a second tuning liquid;

step three: and switching two paths of tuning liquid according to the type of the ion source adjusted by the composite ion source, turning on a first control switch when tuning the electron bombardment source, and turning on a second control switch when tuning the single photon ionization source.

The composite ion source 10 and the mass spectrometer comprising the composite ion source 10 integrate an electron bombardment source and a single photon ionization source in one structure, and during sample detection, the electron bombardment source or the single photon ionization source can be selected according to the type of a sample, or a single photon ionization source mode can be adopted for qualitative detection and analysis under the condition that the composition of the sample is not clear, and the electron bombardment source is adopted for quantitative analysis. After the ion source type is determined, corresponding tuning liquid can be selected for signal debugging, and finally spectrogram analysis is carried out, the whole detection and analysis process can be flexible and changeable, rich fragment peak information can be obtained by using an electron bombardment source, a stable mass spectrogram can be obtained to be matched and retrieved with mass spectrum galleries such as NIST (NIST standard) and the like, a molecular ion peak can be obtained by depending on a single photon ionization source, the qualitative accuracy is improved, the sensitivity of the single photon ionization source is good on the premise of not losing the high sensitivity of the electron bombardment source, and remarkable effects are obtained in the qualitative and quantitative analysis of complex samples.

Compared with the conventional composite ion source, the composite ion source 10 has a simple structure, is easy to install and maintain, and is favorable for commercialization and long-term stable use.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.