Device and method for realizing cluster growth and reaction in atmospheric pressure environment

Abstract

The invention relates to the technical field of particle spectrometers or separation tubes, in particular to a device and method for achieving cluster growth and reaction in the atmospheric pressure environment, the device comprises a reaction shell, an automatic sample injection unit, a temperature control unit and a sample bin, the automatic sample injection unit comprises an injector, a capillary tube and an ionization mechanism, a sample solution is placed in the injector, and the temperature control unit is connected with the ionization mechanism; one end of the capillary tube is connected with the injector, the other end of the capillary tube extends into the reaction shell, the ionization mechanism is mounted at the end, extending into the reaction shell, of the capillary tube, the sample bin is fixedly mounted in the reaction shell, a cluster reaction reagent is placed in the sample bin, and the heating mechanism is arranged at the bottom of the sample bin and connected with the temperature control unit. A gas guide elbow is mounted at the top of the sample bin; a gas nozzle is mounted at the end part of the gas guide elbow. According to the method and the device provided by the invention, efficient growth and reaction of clusters are realized, and reaction products can be directly introduced into a mass spectrometer for analysis.

Description

Technical Field

[0001] This invention relates to the field of particle spectrometers or separation tubes, and more particularly to an apparatus and method for achieving cluster growth and reaction in an atmospheric pressure environment. Background Technology

[0002] Important gaseous molecular clusters in the atmosphere often possess unique structures, bonding properties, and reactivity, making them crucial systems for studying key chemical issues such as catalysis mechanisms, aerosol formation, interstellar chemistry, and the generation of new materials. By controllably altering the size and composition of these clusters, it is possible to investigate the interactions between molecules within them and the formation processes. Existing research has shown that volatile organic compounds (VOCs) can influence or participate in the formation of atmospheric clusters after they reach a certain size, contributing to haze formation. In other words, VOC species generated or present in the environment are crucial to the growth and reactions of related clusters.

[0003] Traditional methods for studying gaseous clusters typically involve directly feeding clusters generated by various ion sources into a mass spectrometer to obtain their composition and structural information. However, current methods can only obtain clusters of relatively small size, making it difficult to reveal the structural patterns during cluster growth and hindering the understanding of the formation and growth mechanisms of atmospheric clusters.

[0004] To solve the above problems, it is necessary to induce further reactions or growth of the clusters after their formation and before mass spectrometry analysis. Currently, the main method used to obtain large-sized clusters is based on gas-phase cluster reactions in flow tubes to achieve cluster growth. For example, adding a reactant gas to a continuous flow tube reactor allows for effective collision reactions with the reactants, enhancing the ion current and increasing the intensity of the detected product signal (capable of detecting cluster signals as small as approximately 1 nm). This technique requires introducing the generated clusters into the flow tube using a buffer gas (such as He), which is relatively complex. During this process, cluster adsorption on the reactor walls may occur, causing cluster loss. Furthermore, the detectable large cluster size is only about 1 nm, making it unsuitable for convenient research on cluster growth and reactivity experiments.

[0005] In another type of gas-phase cluster reaction device, solid organic matter is sublimated into a gaseous state through an evaporation component, and then reacts with flying metal clusters in a reaction tube to grow into metal-organic clusters. This method is mainly applied to clusters with strong interactions between the metal and ligands. Patent CN115631988A discloses a linear ion trap device for realizing the reaction of gas-phase clusters under high-temperature conditions. It can stably provide reaction conditions at different temperatures ranging from room temperature to 1000K for gas-phase cluster reactions. Combined with ion generation sources, mass selectors, mass spectrometers, etc., it can be used to study some chemical behaviors of cluster ions at temperatures up to 1000K. However, these designs still have limitations. On the one hand, the cluster size is still limited (below 1 nm), and the application scope is limited. They can only play a role in the study of clusters with strong interactions between the metal and ligands, but they usually cannot achieve size growth for cluster systems based on weak interactions. On the other hand, in such devices, cluster reactions and growth occur in continuous flow tubes or ion traps, where the pressure conditions are far different from atmospheric pressure, making it difficult to directly apply to cluster studies in atmospheric chemistry. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an apparatus and method for realizing cluster growth and reaction in an atmospheric pressure environment, thereby achieving efficient growth and reaction of clusters under atmospheric pressure, and allowing the reaction products to be directly introduced into a mass spectrometer for analysis.

[0007] A device for achieving cluster growth and reaction in an atmospheric pressure environment includes a reaction shell, an automatic sample injection unit, a temperature control unit, and a sample chamber. The reaction shell is provided with a capillary inlet and a reaction cluster outlet. The automatic sample injection unit includes a syringe, a capillary, and an ionization mechanism. The syringe contains a sample solution. One end of the capillary is connected to the syringe, and the other end extends into the reaction shell from the capillary inlet. The ionization mechanism is installed at the end of the capillary extending into the reaction shell. The sample chamber is fixedly installed inside the reaction shell. The sample chamber has a door and contains cluster reaction reagents. A heating mechanism is provided at the bottom of the sample chamber and is connected to the temperature control unit. A gas guide elbow is installed at the top of the sample chamber, and a gas nozzle is installed at the end of the gas guide elbow.

[0008] Furthermore, the air guide elbow is rotatably connected to the top of the sample chamber.

[0009] Furthermore, the reaction cluster outlet is connected to the mass spectrometer.

[0010] Furthermore, the sample compartment is covered with an insulating layer.

[0011] The optimized sample solution is an aerosol-related precursor.

[0012] The optimized aerosol-related precursors are inorganic acid and dimethylamine solution or inorganic acid and xylene solution.

[0013] The optimized cluster reaction reagent is a volatile organic compound.

[0014] The optimized volatile organic compounds are dimethylamine or xylene.

[0015] A method for achieving cluster growth and reaction in an atmospheric pressure environment includes the following steps; S1: The sample solution enters the reaction shell through the capillary, is ionized to form gaseous ions, and is then ejected, forming seed cluster ions in the reaction area; S2: The cluster reaction reagent in the sample chamber is heated and volatilized to form reaction reagent vapor, which is then transported to the reaction area; S3: Seed cluster ions and reactant vapors in the reaction region come into contact with and combine or react to form reaction clusters; S4: The reaction clusters are output from the reaction cluster outlet to the mass spectrometer for detection and analysis.

[0016] The optimized aerosol-related precursor is an inorganic acid and dimethylamine solution or an inorganic acid and xylene solution, and the cluster reaction reagent is a volatile organic compound.

[0017] Beneficial effects of the invention: The present invention provides an apparatus and method for achieving cluster growth and reaction in an atmospheric pressure environment, which has the following advantages: 1. It can be used to study the growth and reaction of gaseous clusters under atmospheric pressure, and is suitable for research in fields such as atmospheric chemistry. These substances themselves or new substances produced after the reaction can participate in or affect cluster growth, so that the initially formed small-sized clusters can fully complete the growth and reaction that is difficult or impossible to achieve with existing devices before entering the mass spectrometer, and complete the generation of new clusters after the source or the specific enhancement of old clusters, so as to meet the needs of full research on cluster-related topics.

[0018] 2. It can be used for the study of various clusters, not limited to clusters related to metals and ligands. Through the device and method provided by this invention, the obtained clusters can be grown to sizes that were not previously achievable, and the effects of organic acids, volatile organic compounds (VOCs), and high-oxidation-degree organic molecules (HOMs) on cluster formation and growth can be successfully explored, providing a new and convenient method for the study of various cluster-related topics.

[0019] 3. The design is simple and easy to implement. The reaction device is mainly made of metal, which has a low cost. The parts are easy to replace and the vacuum does not need to be broken during replacement.

[0020] 4. The temperature of this invention is controllable, and the generation rate of the reaction gas can be controlled by adjusting the temperature of the heating mechanism.

[0021] 5. It has a wide range of applications and can introduce various substances that are difficult to generate or transport using existing electrospray ionization sources, or other substances that are difficult to participate in clusters through other technologies due to factors such as pH, stability, solubility, or concentration, into appropriate reaction areas. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the present invention.

[0023] Figure 2 This is a schematic diagram comparing the cluster ion intensity of a specific embodiment of the present invention with that of existing methods.

[0024] Figure 3 This is a schematic diagram comparing the cluster ion intensity of a specific embodiment of the present invention with that of existing methods.

[0025] In the diagram: 1. Reaction shell; 101. Reaction cluster outlet; 102. Capillary inlet; 2. Automatic sample feeding unit; 201. Syringe; 202. Ionization mechanism; 203. Capillary; 3. Temperature control unit; 4. Sample chamber; 5. Heating mechanism; 6. Gas guide elbow; 7. Thermal insulation layer; 8. Gas nozzle. Detailed Implementation

[0026] A device for achieving cluster growth and reaction in an atmospheric pressure environment, the schematic diagram of which is shown below. Figure 1 As shown, the system includes a reaction shell 1, an automatic sample injection unit 2, a temperature control unit 3, and a sample chamber 4. The reaction shell is provided with a capillary inlet 102 and a reaction cluster outlet 101. The automatic sample injection unit includes a syringe 201, a capillary 203, and an ionization mechanism 202. The syringe contains a sample solution. One end of the capillary is connected to the syringe, and the other end extends into the reaction shell from the capillary inlet. The ionization mechanism is installed at the end of the capillary that extends into the reaction shell. The sample chamber is fixedly installed inside the reaction shell. The sample chamber is provided with a chamber door and contains cluster reaction reagents. A heating mechanism 5 is provided at the bottom of the sample chamber and is connected to the temperature control unit. A gas guide elbow 6 is installed at the top of the sample chamber, and a gas nozzle 8 is installed at the end of the gas guide elbow.

[0027] Specifically, the sample solution can preferably be an aerosol-related precursor substance, which can be an inorganic acid and dimethylamine solution or an inorganic acid and xylene solution, or other aerosol-related precursor substances.

[0028] The cluster reaction reagent can be a volatile organic compound, preferably dimethylamine or xylene.

[0029] The automated sample introduction unit delivers a sample solution (such as a sulfuric acid and dimethylamine solution) prepared using target cluster structural units into a capillary. A high voltage is applied to the end of the capillary, and molecular ions or small-sized seed cluster ions are formed through an electrospray process or a similar atmospheric pressure ionization method (for example, for a sulfuric acid and dimethylamine solution, sample ions or small-sized cluster ions with sulfuric acid and dimethylamine as structural units can be generated).

[0030] An appropriate amount of reaction reagent for cluster growth is added to the sample chamber. This reagent can be solid, liquid, or solution-based (e.g., in the case of sulfuric acid and dimethylamine, solid dimethylamine can be used in the sample chamber to observe cluster growth). The sample chamber can be equipped with a sliding, removable door for adding and removing the cluster reaction reagent.

[0031] The sample chamber is preferably a rectangular metal box with a length of about 60 mm, a width of about 25 mm, and a height of about 20.5 mm. The top of the sample chamber has a circular opening with a radius of about 5 mm for connecting the air guide elbow.

[0032] The preferred angle of the gas guide bend is 45°. The gas guide bend is rotatably connected to the top of the sample chamber, which allows for full-range rotation of the gas guide bend to adapt to different optimal reaction positions.

[0033] The sample chamber is equipped with a heating mechanism at the bottom. The heating mechanism is connected to the temperature control unit through a temperature detection and control circuit. The temperature control unit can read and control the temperature of the heating mechanism at any time. Preferably, the heating mechanism heats the temperature of the sample chamber to between 20 and 200 degrees Celsius, so as to achieve slow diffusion of the reaction reagent vapor in the reaction area.

[0034] The reagent vapor diffuses slowly within the reaction zone, contacting and combining with or reacting with seed cluster ions generated by the autosampler unit, thereby forming larger cluster ions. Because the reagent vapor interacts gently with the seed cluster ions rather than through violent collisions, this process avoids collision-induced dissociation and fragmentation of the original seed cluster ions. Furthermore, the kinetic energy and density of the escaping reagent vapor can be further reduced by adjusting the temperature of the heating mechanism, optimizing cluster growth and reaction conditions. The resulting reaction clusters can then be directly analyzed by mass spectrometry.

[0035] Furthermore, the sample chamber is covered with a heat-insulating layer 7. This achieves heat preservation of the sample chamber, improves the reaction rate, and reduces reaction costs.

[0036] A method for achieving cluster growth and reaction in an atmospheric pressure environment includes the following steps; S1: The sample solution enters the reaction shell through the capillary, is ionized to form gaseous ions, and is then ejected, forming seed cluster ions in the reaction area; S2: The cluster reaction reagent in the sample chamber is heated and volatilized to form reaction reagent vapor, which is then transported to the reaction area; S3: Seed cluster ions and reactant vapors in the reaction region come into contact with and combine or react to form reaction clusters; S4: The reaction clusters are output from the reaction cluster outlet to the mass spectrometer for detection and analysis.

[0037] The optimized aerosol-related precursor is an inorganic acid and dimethylamine solution or an inorganic acid and xylene solution, and the cluster reaction reagent is a volatile organic compound.

[0038] The apparatus and method provided by this invention enable the growth and reaction of gaseous clusters under atmospheric pressure, applicable to research in fields such as atmospheric chemistry. These substances themselves, or new substances generated after the reaction, can participate in or influence cluster growth, allowing initially small-sized clusters to fully complete the growth and reaction processes that are difficult or impossible to achieve with existing devices before entering the mass spectrometer. This facilitates the generation of new clusters after the source or the specific enhancement of old clusters, meeting the needs of comprehensive research on cluster-related topics. Furthermore, the apparatus and method provided by this invention can be used for various clusters, not limited to metal and ligand-related cluster research. Through the apparatus and method provided by this invention, clusters can be grown to sizes previously unattainable, and the effects of organic acids, VOCs, and HOMs on cluster formation and growth can be successfully explored, providing a new and convenient method for research on various cluster-related topics.

[0039] The device provided by this invention has a simple structure and is easy to implement. The reaction apparatus is mainly made of metal, resulting in low cost. Components are easy to replace without disrupting the vacuum. Furthermore, the temperature of this invention is controllable; the generation rate of the reaction gas can be controlled by adjusting the temperature of the heating mechanism. This invention has a wide range of applications, allowing the introduction of various substances that are difficult to generate or transport using existing electrospray ionization sources, or other substances that are difficult to achieve through other technologies due to factors such as pH, stability, solubility, or concentration, into appropriate reaction areas to participate in cluster formation.

[0040] In a specific embodiment, this invention uses dimethylamine as the cluster reaction reagent and dimethylamine and sulfuric acid solution as the sample solution. The intensity comparison diagram between the reaction clusters formed using the apparatus and method provided by this invention and the dimethylamine-sulfuric acid cluster ions generated directly using an ESI ionization source (without using this invention) is shown below. Figure 2 As shown. Figure 2The upper part of the figure shows the dimethylamine-sulfate cluster ions generated directly using an ESI ionization source (without using the present invention) under optimized experimental conditions. The lower part shows the dimethylamine-sulfate cluster ions observed using the same ESI conditions but with the apparatus and method of the present invention (using dimethylamine as the cluster reaction reagent). (a, b) represent the stoichiometric ratio of the components, and the horizontal axis m / z represents the mass-to-charge ratio of the cluster ions.

[0041] Depend on Figure 2 As can be seen, after using the device and method of the present invention, the intensities of clusters (1,4), (2,5), (3,6), and (4,7) decreased, while the intensities of clusters (2,4), (3,4), (3,5), (4,5), (4,6), (5,6), (5,7), and (6,7) significantly increased. This proves that the clusters generated by the ESI process of the present invention react with the dimethylamine vapor generated by the device to produce clusters containing more dimethylamine molecules. In this application example, the cluster size increased significantly, and the cluster signal was significantly enhanced, demonstrating the effect of the present invention.

[0042] In a specific embodiment, the present invention uses dimethylamine as the cluster reaction reagent and citric acid and sulfuric acid as the sample solution. The intensity comparison diagram between the citric acid-dimethylamine-sulfuric acid reaction clusters formed using the apparatus and method provided by the present invention and the citric acid-sulfuric acid cluster ions generated directly using an ESI ionization source (without using the present invention) is shown below. Figure 3 As shown. Figure 3 The upper part of the figure shows the citrate-sulfuric acid cluster ions produced directly using an ESI ionization source (without using the present invention) under optimized experimental conditions. The lower part of the figure shows the citrate-dimethylamine-sulfuric acid cluster ions observed using the same ESI conditions but with the apparatus of the present invention (using dimethylamine as the cluster reaction reagent). (a, b, c) represent the stoichiometric ratios of the components, and the horizontal axis m / z represents the mass-to-charge ratio of the cluster ions.

[0043] Depend on Figure 3 As can be seen, before using the apparatus and method of this invention, only signals of low-intensity citric acid monomolecules and citric acid-sulfuric acid bimolecules could be observed. However, after using the apparatus and method of this invention, a significant enhancement of the citric acid-sulfuric acid bimolecule signal was detected. More importantly, signals of a series of citric acid-dimethylamine-sulfuric acid cluster ions were discovered. These newly generated cluster ions are clearly products of the reaction between the dimethylamine vapor generated by the apparatus and the citric acid and sulfuric acid ejected from the ESI. In this application example, the cluster reaction reagent vapor generated by the apparatus reacts with the molecules and small clusters ejected from the ESI, producing a series of new clusters, demonstrating the effect of this invention.

[0044] In summary, the present invention provides an apparatus and method for achieving cluster growth and reaction under atmospheric pressure. Under both atmospheric pressure and room temperature conditions, cluster growth and reaction can be achieved efficiently, and the reaction products can be directly introduced into a mass spectrometer for analysis. This solves the problem that existing technologies cannot generate large-sized clusters through reaction. The invention of this apparatus has brought great convenience to research in the fields of cluster chemistry, atmospheric chemistry, and environmental chemistry.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for achieving cluster growth and reaction in an atmospheric pressure environment, characterized in that: The device includes a reaction shell, an automatic sample injection unit, a temperature control unit, and a sample chamber. The reaction shell has a capillary inlet and a reaction cluster outlet. The automatic sample injection unit includes a syringe, a capillary, and an ionization mechanism. The syringe contains a sample solution. One end of the capillary is connected to the syringe, and the other end extends into the reaction shell from the capillary inlet. The ionization mechanism is installed at the end of the capillary that extends into the reaction shell. The sample chamber is fixedly installed inside the reaction shell. The sample chamber has a door and contains cluster reaction reagents. A heating mechanism is provided at the bottom of the sample chamber and is connected to the temperature control unit. A gas guide elbow is installed at the top of the sample chamber, and a gas nozzle is installed at the end of the gas guide elbow.

2. The apparatus for achieving cluster growth and reaction in an atmospheric pressure environment according to claim 1, characterized in that: The air guide elbow is rotatably connected to the top of the sample chamber.

3. The apparatus for achieving cluster growth and reaction in an atmospheric pressure environment according to claim 1, characterized in that: The reaction cluster outlet is connected to the mass spectrometer.

4. The apparatus for achieving cluster growth and reaction in an atmospheric pressure environment according to claim 1, characterized in that: The sample chamber is covered with a heat-insulating layer.

5. The apparatus for achieving cluster growth and reaction in an atmospheric pressure environment according to claim 1, characterized in that: The sample solution is an aerosol-related precursor.

6. The apparatus for achieving cluster growth and reaction in an atmospheric pressure environment according to claim 5, characterized in that: The aerosol-related precursors are inorganic acid and dimethylamine solution or inorganic acid and xylene solution.

7. The apparatus for achieving cluster growth and reaction in an atmospheric pressure environment according to claim 1, characterized in that: The cluster reaction reagent is a volatile organic compound.

8. The apparatus for achieving cluster growth and reaction in an atmospheric pressure environment according to claim 7, characterized in that: The volatile organic compound is dimethylamine or xylene.

9. A method for achieving cluster growth and reaction in an atmospheric pressure environment, comprising using an apparatus for achieving cluster growth and reaction in an atmospheric pressure environment as described in any one of claims 1 to 8, characterized in that: Includes the following steps; S1: The sample solution enters the reaction shell through the capillary, is ionized to form gaseous ions, and is then ejected, forming seed cluster ions in the reaction area; S2: The cluster reaction reagent in the sample chamber is heated and volatilized to form reaction reagent vapor, which is then transported to the reaction area; S3: Seed cluster ions and reactant vapors in the reaction region come into contact with and combine or react to form reaction clusters; S4: The reaction clusters are output from the reaction cluster outlet to the mass spectrometer for detection and analysis.

10. The method for achieving cluster growth and reaction in an atmospheric pressure environment according to claim 9, characterized in that: The aerosol-related precursor is an inorganic acid and dimethylamine solution or an inorganic acid and xylene solution, and the cluster reaction reagent is a volatile organic compound.

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