A mass spectrometry device for direct online analysis of aerosols

Abstract

The present invention discloses a mass spectrometry device for directly analyzing aerosols online, which relates to the technical field of mass spectrometry devices, and comprises a main body, wherein the main body comprises an inner layer pipeline and an outer layer pipeline arranged coaxially; a partition is arranged on the outer layer pipeline, and the partition divides the outer layer pipeline into two parts that are not connected to each other; an aerosol inlet is arranged on the side wall at one end of the outer layer pipeline, a solvent inlet is arranged on the side wall of the outer layer pipeline between the aerosol inlet and the partition, and a carrier gas inlet is arranged on the side wall at the other end of the outer layer pipeline, and the carrier gas inlet and the solvent inlet are located on both sides of the partition; the aerosol inlet and the solvent inlet are both connected to the inner layer pipeline. By controlling the flow rate of the carrier gas, the aerosol in the atmosphere is mixed with the solvent, and is sprayed into the electrospray ionization mass spectrometer through the inner layer pipeline, thereby realizing direct online analysis of the aerosol using the existing electrospray ionization mass spectrometer.

Description

Technical Field

[0001] The present invention relates to the technical field of mass spectrometry devices, and in particular to a mass spectrometry device for directly analyzing aerosols online. Background Art

[0002] Atmospheric aerosols have very complex physical and chemical properties, which have a very important impact on environmental climate, regional air quality, and human health. The complexity of aerosols is reflected in the extremely wide range of particle sizes, which can range from a few nanometers to millimeters, and the chemical composition can be a mixture of multiple primary emissions and secondary formation substances. In addition, since aerosol particles have a large relative area, their composition is extremely unstable and will continue to change with time and weather factors. How to accurately and effectively analyze the chemical components of aerosols, especially the rapid online identification of organic components in particulate matter, is crucial in various fields such as environmental protection, industrial production, and health effect assessment.

[0003] Mass spectrometers have played a huge role in chemical analysis due to their ability to accurately measure mass, and have also been widely used in aerosol component analysis. At present, there are usually two mass spectrometry analysis methods for organic components in atmospheric aerosols: one is mass spectrometry detection technology based on offline sampling, and the other is mass spectrometry detection technology based on online analysis. Unlike gases, aerosols are often difficult to directly enter mass spectrometers for chemical component analysis. Therefore, the typical offline analysis method is usually to collect atmospheric aerosol particles with a filter membrane for a certain period of time, and then dissolve and extract the collected particles, and use gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS) or other mass spectrometry instruments for offline analysis. Many analytical laboratories have conventional gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS), especially liquid chromatography-mass spectrometry (ESI-MS) based on electrospray ionization, which has played a huge role in organic matter analysis. However, there are relatively few reports on the use of these instruments for online direct aerosol analysis. In order to enable online direct mass spectrometry analysis of aerosols, a variety of dedicated mass spectrometers and interfaces for mass spectrometry have been designed and applied. Aerosol mass spectrometer (AMS) is a mass spectrometer specifically used for online analysis of aerosols. It can directly introduce aerosol particles into the mass spectrometer, and vaporize organic components through high-temperature heat, and then use time-of-flight mass spectrometry to detect components, and can analyze various types of organic matter. The single particle mass spectrometer (SPMS) uses a laser desorption ionization source to detect the chemical components in a single particle. It has also been reported that the electrospray extraction ionization source (EESI) can be combined with atmospheric pressure mass spectrometry to achieve online analysis of aerosols. In addition, online thermal desorption devices are widely used in conjunction with mass spectrometry. Online thermal desorption devices can automatically collect particles on the filter membrane surface, and desorb organic components through a program-controlled depyrogenation device, and then analyze them using gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS) or chemical ionization source mass spectrometry (CI-TOFMS).

[0004] Offline mass spectrometry requires a long analysis time, so it reflects the dynamic changes of atmospheric aerosols. In addition, during the process from offline sampling to pre-treatment, the aerosols may have undergone chemical aging and secondary reactions in their composition, resulting in the analysis results not being representative of the state of the original sample.

[0005] Currently, common dedicated aerosol online analysis mass spectrometers, including aerosol mass spectrometers (AMS) and single particle mass spectrometers (SPMS), have their own problems: these technologies generally use electron bombardment ionization sources and laser ionization sources. These hard ionization methods will turn the organic components to be analyzed into organic fragments, which poses serious challenges to the analysis of the complex composition of aerosols or even makes it impossible to analyze. Electrospray extraction ionization source (EESI) can be combined with atmospheric pressure mass spectrometry to achieve online analysis of aerosols, but the device is relatively complex and difficult to install and debug, resulting in poor reproducibility.

[0006] There are also many problems with the pretreatment device based on online thermal desorption. First, the device is expensive and difficult to be widely used. Second, the desorption method based on heating will easily make some non-volatile organic compounds difficult to detect. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a mass spectrometry device for direct online analysis of aerosols, so as to make full use of the electrospray ionization atmospheric pressure mass spectrometry (ESI-MS) available in most chemical analysis laboratories to realize direct real-time online analysis of aerosols.

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] The present invention provides a mass spectrometry device for directly analyzing aerosols online, comprising a main body, wherein the main body comprises an inner pipeline and an outer pipeline arranged coaxially; a partition is arranged on the outer pipeline, and the partition divides the outer pipeline into two parts that are not connected to each other; an aerosol inlet is arranged on the side wall of one end of the outer pipeline, a solvent inlet is arranged on the side wall of the outer pipeline between the aerosol inlet and the partition, and a carrier gas inlet is arranged on the side wall of the other end of the outer pipeline, and the carrier gas inlet and the solvent inlet are located on both sides of the partition; the aerosol inlet and the solvent inlet are both connected to the inner pipeline.

[0010] Optionally, one end of the outer layer pipeline is longer than the inner layer pipeline, and the other end of the outer layer pipeline is flush with the inner layer pipeline.

[0011] Optionally, the end portion of the other end of the outer layer pipeline is configured to be a tapered structure that contracts toward the axial direction of the outer layer pipeline.

[0012] Optionally, the aerosol inlet is a conical mouth.

[0013] Optionally, the aerosol inlet, the solvent inlet and the carrier gas inlet are located on the same side of the outer pipeline.

[0014] Optionally, the diameter of the inner layer pipeline is 100 microns, and the diameter of the outer layer pipeline is 250 microns.

[0015] Optionally, the length of the inner pipeline is 150 mm.

[0016] Optionally, the solvent introduced into the solvent inlet is methanol or acetonitrile.

[0017] Optionally, the carrier gas introduced into the carrier gas inlet is nitrogen or argon.

[0018] Optionally, the outer pipeline is electrically connected to a power supply device.

[0019] Optionally, in the outer pipeline, the flow velocity of the carrier gas is 300-600m / s.

[0020] Compared with the prior art, the present invention has achieved the following technical effects:

[0021] 1. The device can pass the organic components in atmospheric aerosols into the injection port of the electrospray ionization mass spectrometer for direct online analysis, avoiding the changes in sample properties caused by traditional sampling and analysis, and can reflect the original composition of atmospheric aerosols to the greatest extent;

[0022] 2. The device has extremely high measurement time resolution, can measure the composition of organic aerosols within minutes, and can dynamically reflect the changes in the chemical composition of atmospheric aerosols;

[0023] 3. This method uses ESI soft ionization source to generate molecular ion information of organic components, avoiding the problem of generating a large number of organic fragments by laser ionization and electron bombardment ionization, thus improving the qualitative and quantitative capabilities of organic components;

[0024] 4. The device has a very simple structure and can fully utilize the advantages of the stability of the ESI electrospray source, avoiding problems such as the instability of ionization sources such as EESI;

[0025] 5. It is easy to use atmospheric pressure mass spectrometer to perform real-time online detection of aerosols and volatile organic compounds.

[0026] 6. It is applicable to almost all types of electrospray ionization mass spectrometers currently available, and can maximize resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 Schematic diagram of a mass spectrometry device for direct online analysis of aerosols;

[0029] Figure 2 Schematic diagram of the aerosol inlet of a mass spectrometry device for direct online analysis of aerosols.

[0030] Explanation of the reference numerals: 1. aerosol inlet; 2. solvent inlet; 3. carrier gas inlet; 4. spray; 5. ion. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] This embodiment specifically discloses a mass spectrometry device for directly analyzing aerosols online, such as Figure 1-2 As shown, it includes a main body, which includes an inner pipeline and an outer pipeline arranged coaxially; a partition is arranged on the outer pipeline, and the partition divides the outer pipeline into two parts that are not connected to each other; an aerosol inlet 1 is arranged on the side wall of one end of the outer pipeline, and a solvent inlet 2 is arranged on the side wall of the outer pipeline between the aerosol inlet 1 and the partition, and a carrier gas inlet 3 is arranged on the side wall of the other end of the outer pipeline, and the carrier gas inlet 3 and the solvent inlet 2 are located on both sides of the partition; the aerosol inlet 1 and the solvent inlet 2 are both connected to the inner pipeline.

[0033] The length of one end of the outer layer pipeline exceeds that of the inner layer pipeline, and the other end of the outer layer pipeline is flush with the inner layer pipeline. The end of the other end of the outer layer pipeline is configured to be a conical structure that contracts toward the axial direction of the outer layer pipeline. The aerosol inlet 1 is a conical opening. The aerosol inlet 1, the solvent inlet 2 and the carrier gas inlet 3 are located on the same side of the outer layer pipeline.

[0034] The inner layer pipeline has a diameter of 100 microns, and the outer layer pipeline has a diameter of 250 microns. The inner layer pipeline has a length of 150 mm. The solvent introduced into the solvent inlet 2 is methanol. The carrier gas introduced into the carrier gas inlet 3 is nitrogen. In the outer layer pipeline, the flow velocity of the carrier gas is 400 m / s.

[0035] The outer pipeline is electrically connected to a power supply device, and the power supply device provides a certain voltage to the outer pipeline.

[0036] A quantitative injection pump is used to inject the solvent at a fixed flow rate, and an interface will be formed in the outer pipeline. The atmospheric aerosol sample to be analyzed will hit the liquid interface at a certain flow rate (600ml / min in the experiment) and a certain speed for the interaction between the aerosol and the solvent. The liquid will form a concave surface under the action of the atmospheric airflow, and the atmospheric aerosol will come into contact with the liquid under the action of inertia, and thus be captured by the organic solvent. In order to improve the efficiency of the collision and dissolution of the aerosol and organic components, the aerosol flow injection hole adopts a conical design to form a diffused airflow, which hits the liquid surface and increases the contact probability of the gas-liquid interface. Subsequently, the organic components in the aerosol will be dissolved by the methanol solvent and drawn out through the internal capillary.

[0037] A certain voltage is applied to the outer pipeline. Under the action of voltage and gas pressure, the sample to be tested in the inner pipeline is ejected at the tip of the outer pipeline to form an electrospray 4 and generate sample ions 5. The carrier gas can not only refine the small droplets ejected from the tip of the outer pipeline, but also facilitate desolvation. Then, the generated ions 5 enter the mass spectrometer for detection via the atmospheric pressure mass spectrometer interface. During the experiment, the continuous aerosol injection gas flow and the continuous injection of solvent and carrier gas are maintained, so that real-time online analysis of organic aerosols in the atmosphere can be achieved.

[0038] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

[0039] The present specification uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A mass spectrometry device for direct online analysis of aerosols, characterized in that: The invention comprises a main body, wherein the main body comprises an inner layer pipeline and an outer layer pipeline which are arranged coaxially; a partition is arranged on the outer layer pipeline, and the partition divides the outer layer pipeline into two parts which are not connected to each other; an aerosol inlet is arranged on the side wall at one end of the outer layer pipeline, a solvent inlet is arranged on the side wall of the outer layer pipeline between the aerosol inlet and the partition, and a carrier gas inlet is arranged on the side wall at the other end of the outer layer pipeline, and the carrier gas inlet and the solvent inlet are located on both sides of the partition; the aerosol inlet and the solvent inlet are both connected to the inner layer pipeline; One end of the outer layer pipeline is longer than the inner layer pipeline, and the other end of the outer layer pipeline is flush with the inner layer pipeline; The aerosol inlet, the solvent inlet and the carrier gas inlet are located on the same side of the outer layer pipeline.

2. The mass spectrometry device for direct online analysis of aerosol according to claim 1, characterized in that: The end portion of the other end of the outer layer pipeline is configured to be a tapered structure that contracts toward the axial direction of the outer layer pipeline.

3. The mass spectrometry device for direct online analysis of aerosol according to claim 1, characterized in that: The aerosol inlet is a cone-shaped opening.

4. The mass spectrometry device for direct online analysis of aerosol according to claim 1, characterized in that: The inner layer pipeline has a diameter of 100 microns, and the outer layer pipeline has a diameter of 250 microns.

5. The mass spectrometry device for direct online analysis of aerosols according to claim 1, characterized in that: The length of the inner layer pipeline is 150 mm.

6. The mass spectrometry device for direct online analysis of aerosols according to claim 1, characterized in that: The solvent introduced into the solvent inlet is methanol or acetonitrile.

7. The mass spectrometry device for direct online analysis of aerosols according to claim 1, characterized in that: The carrier gas introduced into the carrier gas inlet is nitrogen or argon.

8. The mass spectrometry device for direct online analysis of aerosols according to claim 1, characterized in that: The outer pipeline is electrically connected to the power supply device.

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