CN110706997A - A soft x-ray ion source - Google Patents

Abstract

The invention belongs to the technical field of ionization sources, and in particular relates to a soft x-ray ion source, comprising a radiation source and a protection device. A cavity, the protection device is provided with an opening, and the opening is connected to the cavity for docking the ion source structure and the atmospheric pressure interface. Low astigmatism, high energy, sufficient sample ionization energy, no problems of desolvation and ion sampling efficiency, high sensitivity, and good reproducibility of results; it can effectively solve the insufficient ionization and adduct of samples caused by ion suppression effect. The influence of cluster ions on the analysis; the samples that are difficult to ionize can be ionized to obtain complete ionized products, reducing background interference, and at the same time, it can also be achieved by introducing specific auxiliary sample radiation ionization aids.

Description

A soft x-ray ion source

technical field

The invention belongs to the technical field of ionization sources, and in particular relates to a soft X-ray ion source.

Background technique

The ion source is the core component of the mass spectrometer. It ionizes the injected neutral substances into ions. It is the first step in the realization of mass spectrometry and plays a very important role in the field of mass spectrometry technology. There are many types of ion sources, including vacuum ionization sources and atmospheric pressure ionization sources. Vacuum ionization sources such as fast atom bombardment ionization sources (FAB), electron bombardment ionization sources (EI), chemical ionization sources (CI), etc., these ionization sources all need to work under certain vacuum conditions, while atmospheric pressure ionization sources can be used. Electrospray ionization source (ESI) is a representative ion source working in atmospheric environment. As a relatively new ionization technology, electrospray ionization source has its own unique advantages and broad development prospects and has attracted much attention. .

Electrospray Ionization, also known as ESI source, is compatible with a variety of sample introduction methods, such as liquid chromatography, capillary electrophoresis, and microfluidics. This ionization technique can not only analyze macromolecular compounds, but also generate multiply-charged ions during the ionization process. The types of compounds that can be analyzed are very large, including organic compounds, drugs and their metabolites, proteins, peptides, sugars, etc. Therefore, the electrospray ionization source is of great significance to the development and application of the entire mass spectrometry technology, and the technology also won the Nobel Prize in Chemistry in 2002. The electrospray ionization source has high requirements on the flow rate. Generally speaking, the lower the flow rate, the higher the sensitivity. The main reason is that the high flow rate is not suitable for the desolvation process. The current model mechanism of ESI is Coulomb explosion. If the flow rate is too high, it will not be fully desolvated before entering the vacuum interface, and the normal ion signal will not be obtained. Therefore, under some specific analysis conditions, nano-ESI is also required, and the flow rate can be reduced to the nL level. ESI sources are generally limited by the flow rate of the liquid phase, and low-flow ESI sources tend to achieve a higher degree of desolvation, resulting in higher ion transmission efficiency and resolution. However, during LC-MS analysis, a faster sample liquid flow rate is usually required, and the radius of the droplet is proportional to the flow rate, which increases the time and distance required for desolvation, resulting in a low degree of desolvation and a vacuum The sampling efficiency of the interface is not high, thus losing the high resolution of the low flow ESI source. Moreover, ESI will have obvious ion suppression effect in working engineering (typically under high salt conditions), and additive ions including water clusters will also affect the analysis. In order to solve this series of problems, the atmospheric pressure chemical ionization source APCI and the atmospheric pressure photoionization source APPI were derived. These ion sources have similar structures and are effective supplements to the ESI source.

At the same time, vacuum ultraviolet single-photon dissociation (PI) technology is also used to ionize some weakly polar substances, which solves the analysis problem of a large number of complex systems with non-polar components. Chinese Patent Publication No. CN101329299A "New Electrospray Sampling Vacuum Ultraviolet Single Photon Ionization Mass Spectrometry Device" and, which use electrospray technology to prepare compound ions, vacuum ultraviolet lamp or synchrotron radiation as light source, in the vacuum ultraviolet wavelength range less than 200nm A method of irradiating ions inside to obtain sample ions. At the same time, the Chinese Patent Publication No. CN103762150A "Volatile Solvent Assisted Ionization Low Pressure Photoionization Mass Spectrometry Device for Ultrasonic Atomization Sample Injection" combines vacuum ultraviolet single photon ionization technology with ultrasonic atomization volatile solvent technology. However, the light sources used in these technical disclosures are limited to the vacuum ultraviolet wavelength range (100-200 nm), and the samples to be tested need to be dissolved in volatile organic solvents to characterize macromolecular segments and polypeptides that are not easily soluble and have complex structures. has certain limitations. Although vacuum ultraviolet single-photon dissociation has high efficiency, due to its low energy, it cannot cover the absorption edges of some important atoms, and the dissociation has no atomic selectivity, and it is difficult to dissociate macromolecules in a direction. At the same time, there is also the method of using hydrated proton (H ₃ O ⁺ ) transfer as the ionization source. Protons react and are ionized. This method has a simple structure and obvious molecular ion peaks. It is an excellent soft ionization technology. However, there are alcohols, aldehydes and long-chain alkanes, and the application of this method will be greatly limited. For example, under normal test conditions for n-butanol, the molecular ion peak cannot be detected, and only the peak of butene with dehydroxylated groups can be detected, which brings great difficulties to the test of n-butanol.

Among the existing atmospheric pressure ion sources, it is difficult to find an ion source with a general solution. Various ion sources have more or less limitations in analyzing the types of samples, mainly due to more or less problems in energy acquisition. .

In order to solve the above problems, a soft x-ray ion source is proposed in the present application.

SUMMARY OF THE INVENTION

In order to solve the above problems, the soft x-ray ion source proposed by the present invention forms a high-energy plasma atmosphere in the surrounding space environment through short-wave radiation in a specific wavelength range, and can directly ionize the surrounding air background and the sample in an all-round way, ensuring that there is no pretreatment or Complete non-discriminatory ionization of complex sample components with matrix assistance.

The technical scheme adopted by the present invention to solve its technical problems is:

A soft x-ray ion source includes a radiation source and a protection device, the radiation source is mounted on the protection device, the protection device is provided with a cavity for covering short-wave radiation generated by the radiation light source, and the protection device is provided with an opening, and the opening is in conduction with the cavity for docking the ion source structure and the atmospheric pressure interface;

The short-wave radiation output by the radiation light source is directed into the protection device, and an excited high-energy state environment area is formed in the cavity;

A sample lead-in and release mechanism is installed on the protection device, which is used for placing the sample in the excitation high-energy state environment region.

As a solution of the present invention, the sample introduction and release mechanism adopts a liquid introduction pipe, and the liquid introduction pipe is installed on the protection device and communicated with the cavity.

As a solution of the present invention, the sample introduction mechanism adopts a placing table, and the placing table is installed on the protection device and located in the cavity.

As a solution of the present invention, the wavelength band of the short-wave radiation generated by the radiation light source is located between the ultraviolet band and the hard X-ray band on the electromagnetic spectrum, and the spectral range is 0.3mn-40nm, the photon ability is 29eV-9999eV, and its intensity can be The light-emitting process is in the form of continuous or discontinuous pulses.

As a solution of the present invention, the opening is provided with an ion concentrator for focusing the ions generated inside the ion source.

As a solution of the present invention, the protection device is connected with a vacuum pump, which is used for pumping air from the cavity to form a low-pressure environment, and the pressure value of the low-pressure environment is 0.1Pa-1e4Pa.

As a solution of the present invention, the protection device is provided with an auxiliary structure for passing an auxiliary agent for assisting the radiation ionization of the sample, and the auxiliary structure is communicated with the cavity.

As an aspect of the present invention, the auxiliary agent includes at least one of methanol, ethanol, water vapor, hydrogen sulfide, methane, helium, and nitrogen.

As an aspect of the present invention, the auxiliary structure is a pipeline, and the auxiliary agent is passed into the cavity of the protection device through the pipeline.

As a solution of the present invention, the auxiliary structure is a flange.

The above-mentioned technical scheme of the present invention has the following beneficial technical effects:

1. The short-wave radiation source used in the present invention is small in size, simple in structure, adjustable in wavelength band, low in stray light, high in energy, sufficient in sample ionization energy, and does not have the problems of desolvation and ion sampling efficiency, high sensitivity, and heavy results. Good performance.

2. The soft X-ray ion source in the present invention can effectively solve the influence of insufficient ionization of the sample and adducted cluster ions caused by the ion suppression effect on the analysis.

3. The soft X-ray ion source in the present invention can ionize samples that are difficult to ionize (especially biological macromolecules) to obtain complete ionized products, and the structure can assist in vacuuming, reduce background interference, and can also introduce specific auxiliary The sample radiation ionization assistant realizes a. Assisted ionization and the ability to enrich fingerprint fragment information; b. Suppresses background chemical noise interference and obtains molecular precursor ion information.

4. It has a wide range of applications, can tolerate a certain degree of salt and buffer, and does not require strict sample processing. It can even directly analyze untreated biological samples, thereby simplifying the tedious sample preparation process.

Description of drawings

FIG. 1 is a schematic diagram of a structure proposed by the present invention in Embodiment 1. FIG.

FIG. 2 is a schematic diagram of a structure proposed by the present invention in Embodiment 2. FIG.

FIG. 3 is a schematic diagram of a structure proposed by the present invention in Embodiment 2. FIG.

FIG. 4 is a schematic diagram of a structure proposed by the present invention in Embodiment 2. FIG.

FIG. 5 is a schematic diagram of a structure proposed by the present invention in Embodiment 3. FIG.

FIG. 6 is a schematic diagram of a structure proposed by the present invention in Embodiment 4. FIG.

FIG. 7 is a schematic diagram of a structure proposed by the present invention in Embodiment 4. FIG.

FIG. 8 is a schematic diagram of a structure proposed by the present invention in Embodiment 4. FIG.

Detailed ways

In order to make the technical means, creative features, goals and effects realized by the present invention easy to understand, the present invention will be further described below with reference to specific embodiments and accompanying drawings, but the following embodiments are only preferred embodiments of the present invention, not all of them. . Based on the examples in the implementation manner, other examples obtained by those skilled in the art without creative work shall fall within the protection scope of the present invention. Also, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concepts of the present invention.

Specific embodiments of the present invention will be described below with reference to the accompanying drawings. The following specific embodiments may be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

The above-mentioned soft X-ray ion source:

Example 1

As shown in Figure 1, in the figure: 101, radiation source; 102, protective device; 103, liquid introduction pipe; 104, excited high-energy state environment area; 105, opening.

Among them, it can be understood that the radiation light source 101 is used to generate X-rays covering the high-energy region, that is, to excite the high-energy state environment region 104, the opening 105 is the docking position of the ion source structure and the atmospheric pressure interface, and the rear end is docked to the vacuum chamber of the mass spectrometer, which specifically includes All levels of ion guides, mass analyzers, ion detectors, etc. must be structured; the liquid sample enters the cavity from the liquid introduction nozzle 103 by manual injection or peristaltic pump, and completes ionization, declustering and A series of processes such as desolvation are performed, and the negative pressure environment of the mass spectrometer atmospheric pressure interface of the opening 105 enters the mass spectrometer to complete the whole process of ionization and entering the mass spectrometer. It should be further noted that the wavelength band of the short-wave radiation generated by the radiation light source 101 is located between the ultraviolet band and the hard X-ray band on the electromagnetic spectrum, and the spectral range is 0.3mn-40nm, the photon capability is 29eV-9999eV, and its intensity is adjustable, The light-emitting process is in the form of continuous or discontinuous pulses.

Example 2

As shown in Figure 2-3, in the figure: 101, radiation source; 102, protection device; 103, liquid introduction pipe; 104, excited high-energy state environment area; 105, opening; 106 auxiliary structure; 107, vacuum pump; 108, ion polymerization light piece.

The difference from Example 1 is that in order to improve the performance of the ion source, some supplementary structures are added.

The auxiliary structure 106 is added in FIG. 2. In this embodiment, the auxiliary structure 106 can be a pipeline for introducing the auxiliary sample radiation ionization auxiliary into the cavity. It is further necessary to specify that the auxiliary is methanol, ethanol , at least one of water vapor, hydrogen sulfide, methane, helium, and nitrogen, for example, the auxiliary agents are methanol and water vapor. To complete the function of improving ionization efficiency or suppressing background chemical noise interference, of course, the auxiliary structure 106 can also be other structures capable of guiding the above-mentioned auxiliary agent into the cavity.

In FIG. 3 , a vacuum pump 107 is added to pump air from the cavity to form a low-pressure environment. The pressure value of the low-pressure environment is 0.1Pa-1e4Pa, which can further assist in suppressing background chemical noise interference and help the interior of the environment as much as possible. Many are filled with auxiliary sample radiation ionization aids.

In FIG. 4 , an ion concentrator 108 is added. In this embodiment, the ion concentrator 108 is an ion lens, which is used to better focus the ions generated inside the ion source and introduce more atmospheric pressure into the post-stage mass spectrometer. interface to improve overall efficiency. Of course, in some embodiments, the ion concentrator 108 may also be other ion concentrators. The whole ionization process is the same as that in Example 1, and the auxiliary structures added are all to improve the ionization efficiency and reduce the background interference in the environment, which helps to improve the ionization efficiency and sensitivity of the ion source.

Example 3

As shown in FIG. 5 , in the figure: 201, radiation light source; 202, protection device; 203, placing table; 204, exciting high-energy state environment area; 205, opening.

Among them, it can be understood that the radiation light source 201 is used to generate X-rays covering the high-energy region, that is, to excite the high-energy state environment region 204, the opening 205 is the docking position of the ion source structure and the atmospheric pressure interface, and the rear end is docked to the vacuum chamber of the mass spectrometer, which specifically includes All levels of ion guides, mass analyzers, ion detectors, etc. must be structured; the liquid or fixed sample is placed in the sample tank on the placement stage 203, and ionization, declustering and desolvation are completed in the excited high-energy state environment region 204. A series of processes, and the negative pressure environment of the mass spectrometer atmospheric pressure interface of the opening 205 enters the mass spectrometer to complete the whole process of ionization and entering the mass spectrometer. It should be further noted that the wavelength band of the short-wave radiation generated by the radiation light source 101 is located between the ultraviolet band and the hard X-ray band on the electromagnetic spectrum, and the spectral range is 0.3mn-40nm, the photon capability is 29eV-9999eV, and its intensity is adjustable, The light-emitting process is in the form of continuous or discontinuous pulses.

Example 4

As shown in Figure 6-8, in the figure: 201, radiation source; 202, protection device; 203, placing table; 204, excited high-energy state environment area; 205, opening; 206, auxiliary structure; 207, vacuum pump; 208, ion Spotlight.

Different from Embodiment 3, in order to improve the performance of the ion source, some supplementary structures are added.

The auxiliary structure 206 is added in FIG. 6. In this embodiment, the auxiliary structure 206 can be a pipeline for introducing the auxiliary sample radiation ionization auxiliary into the cavity. It is further necessary to specify that the auxiliary is methanol, ethanol , at least one of water vapor, hydrogen sulfide, methane, helium, and nitrogen, for example, the auxiliary agents are methanol and water vapor. To complete the function of improving ionization efficiency or suppressing background chemical noise interference, of course, the auxiliary structure 206 can also be other structures capable of guiding the above-mentioned auxiliary agent into the cavity.

In FIG. 7 , a vacuum pump 207 is added to pump air from the cavity to form a low-pressure environment. The low-pressure environment has a pressure value of 0.1Pa-1e4Pa, which can further assist in suppressing background chemical noise interference and help the interior of the environment as much as possible. Many are filled with auxiliary sample radiation ionization aids.

In FIG. 8 , an ion concentrator 208 is added. In this embodiment, the ion concentrator 208 is an ion lens, which is used to better focus the ions generated inside the ion source and introduce more atmospheric pressure into the post-stage mass spectrometer. interface to improve overall efficiency.

Of course, in some embodiments, the ion concentrator 208 can also be other ion concentrators. The entire ionization process is the same as that in Example 3, and the auxiliary structures added are all to improve the ionization efficiency and reduce the background interference in the environment, which helps to improve the ionization efficiency and sensitivity of the ion source.

The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and the above-mentioned embodiments and descriptions are only preferred examples of the present invention, and are not intended to limit the present invention, without departing from the spirit and scope of the present invention. Under the premise, the present invention will also have various changes and improvements, and these changes and improvements all fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.

Claims (10)

1. A soft x-ray ion source is characterized by comprising a radiation light source and a protection device, wherein the radiation light source is arranged on the protection device, the protection device is provided with a cavity used for covering short-wave radiation generated by the radiation light source, the protection device is provided with an opening, and the opening is communicated with the cavity and used for butt joint of an ion source structure and an atmospheric pressure joint;

short-wave radiation output by the radiation light source faces the inside of the protection device, and an excited high-energy state environment region is formed in the cavity;

and the protection device is provided with a sample leading and discharging mechanism for placing a sample in the excited high-energy state environment area.

2. The soft x-ray ion source of claim 1, wherein the sample placement mechanism employs a liquid introduction nozzle mounted to the protective device and in fluid communication with the chamber.

3. The soft x-ray ion source of claim 1, wherein the sample indexing mechanism employs a placement stage mounted to the protective device and positioned in the chamber.

4. A soft X-ray ion source according to claim 1, wherein the radiation source generates short wavelength radiation in a wavelength band between the ultraviolet and hard X-ray wavelength bands of the electromagnetic spectrum, and has a spectral range of 0.3mn-40nm, a photon energy of 29eV-9999eV, an intensity modulation, and a luminescence in the form of continuous or discontinuous pulses.

5. The soft x-ray ion source of claim 1, wherein the opening is provided with an ion condenser for focusing ions generated within the ion source.

6. The soft x-ray ion source of claim 1, wherein the protective device is coupled to a vacuum pump for evacuating the chamber to form a low pressure environment, the low pressure environment having a pressure value of 0.1Pa to 1e4 Pa.

7. The soft x-ray ion source of claim 1, wherein the protective device is provided with an auxiliary structure for introducing an auxiliary agent for assisting in ionizing radiation of the sample, the auxiliary structure being in communication with the chamber.

8. The soft x-ray ion source of claim 7, wherein the auxiliary agent comprises at least one of methanol, ethanol, water vapor, hydrogen sulfide, methane, helium, and nitrogen.

9. The soft x-ray ion source of claim 7 or 8, wherein the auxiliary structure is a conduit through which the auxiliary agent passes into the cavity of the protective device.

10. The soft x-ray ion source of claim 7, wherein the auxiliary structure is a flange.

Images