sampling tube

Abstract

The application relates to a sampling tube, comprising: a shell, a filtering channel is formed in the shell, and an inlet and an outlet are arranged on the shell and located at the axial opposite ends of the filtering channel; and a main suction accessory, which is sleeved in the filtering channel and is in fluid communication between the inlet and the outlet; wherein the main suction accessory comprises a porous base and a molecularly imprinted polymer loaded on the porous base, and the molecularly imprinted polymer selectively adsorbs nicotine. In the sampling tube, the to-be-detected airflow enters the filtering channel from the inlet of the shell, and after the nicotine in the to-be-detected airflow is adsorbed by the main suction accessory, the to-be-detected airflow is discharged from the outlet. The porous base on the main suction accessory allows the to-be-detected airflow to flow through the main suction accessory, and the molecularly imprinted polymer loaded on the porous base can selectively adsorb nicotine, prevent coexisting substances and other interfering molecules from being adsorbed, and improve the adsorption accuracy of nicotine molecules and the subsequent detection precision.

Description

Technical Field

[0001] This application relates to the field of atomization technology, and in particular to sampling tubes. Background Technology

[0002] Aerosols are colloidal dispersion systems formed by the dispersion and suspension of solid or liquid particles in a gaseous medium. Since aerosols can be absorbed by the human body through the respiratory system, electronic atomization devices atomize aerosols to generate a matrix-based aerosol, providing users with a new alternative absorption method.

[0003] To detect nicotine in aerosols, traditional adsorption techniques employ sampling tubes made of glass or stainless steel, filled with porous adsorbents such as activated carbon or silica gel. These adsorbents capture nicotine molecules from the aerosols through physical adsorption. However, traditional adsorption tubes lack specificity for nicotine adsorption and readily capture coexisting nicotine components such as propylene glycol and glycerin (e.g., propylene glycol adsorption rate >35%). Therefore, traditional adsorption tubes adsorb not only nicotine but also nicotine coexisting compounds, which can interfere with subsequent nicotine content detection, leading to significant errors. Utility Model Content

[0004] Therefore, it is necessary to provide a sampling tube to address the problem that traditional adsorption tubes are prone to causing subsequent detection errors.

[0005] A sampling tube, comprising:

[0006] A housing, wherein a filter channel is formed within the housing, and the housing has an inlet and an outlet located at opposite axial ends of the filter channel, respectively: and

[0007] The main adsorption element is fitted inside the filter channel and is fluidly connected between the inlet and the outlet;

[0008] The main adsorbent comprises a porous matrix and a molecularly imprinted polymer loaded on the porous matrix, wherein the molecularly imprinted polymer selectively adsorbs nicotine.

[0009] In some embodiments, the molecularly imprinted polymer is configured as a renewable material.

[0010] In some embodiments, the porous matrix includes at least one of alumina and porous silicon carbide ceramics.

[0011] In some embodiments, the sampling tube includes a pre-filter sleeved within the filter channel and located between the inlet and the main adsorption element, the pre-filter being made of a nanofiber membrane.

[0012] In some embodiments, the pre-filter comprises at least one of polyvinylidene fluoride electrospun fiber membrane and electrospun polyimide membrane.

[0013] In some embodiments, the sampling tube includes a protective element that seals at least one of the inlet and the outlet while allowing airflow.

[0014] In some embodiments, the protective element is a droplet barrier layer, and the contact angle of the droplet barrier layer is ≥100°.

[0015] In some embodiments, the protective element is made of at least one of silane-modified glass fiber woven layer and polytetrafluoroethylene coated nonwoven fabric.

[0016] In some embodiments, the sampling tube includes a nicotine evaporation-resistant coating applied to the inner wall of the housing, and the nicotine evaporation-resistant coating at least covers the outer surface of the main adsorption element.

[0017] In some embodiments, the sampling tube includes a mounting connector, which is provided at at least one of the two ends of the housing having the inlet and the outlet, the mounting connector being used for mounting connection with an air extraction component or an air delivery component.

[0018] In the aforementioned sampling tube, the gas stream to be tested enters the filter channel through the inlet of the shell. After the nicotine in the gas stream is adsorbed by the main adsorbent, the gas stream is discharged from the outlet. The main adsorbent comprises a porous matrix and a molecularly imprinted polymer loaded on the porous matrix. The porous matrix allows the gas stream to flow through the main adsorbent, while the molecularly imprinted polymer loaded on the porous matrix selectively adsorbs nicotine. This specific adsorption of nicotine molecules by the molecularly imprinted polymer prevents the adsorption of nicotine coexisting molecules and other interfering molecules, improving the accuracy of nicotine adsorption and subsequent detection precision. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the sampling tube structure in some embodiments of this application;

[0020] Figure 2 This is a schematic diagram of the sampling tube structure in some other embodiments of this application.

[0021] Explanation of reference numerals in the attached drawings: 100, sampling tube; 10, outer shell; 11, filter channel; 13, inlet; 15, outlet; 30, main adsorption element; 50, pre-filter element; 70, protective element; 80, anti-nicotine volatilization layer; 90, mounting connector. Detailed Implementation

[0022] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0023] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0026] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0027] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0028] See Figure 1 In some embodiments of this application, a sampling tube 100 is provided. After a preparatory airflow is introduced into the sampling tube 100, the nicotine in the airflow is selectively adsorbed into the sampling tube 100, which can accurately adsorb and collect the nicotine in the airflow and improve the accuracy of subsequent detection.

[0029] The sampling tube 100 includes a shell and a main adsorbent 30. A filter channel 11 is formed inside the shell, and an inlet 13 and an outlet 15 are provided on the shell at opposite axial ends of the filter channel 11. The main adsorbent 30 is fitted inside the filter channel 11 and is in fluid communication between the inlet 13 and the outlet 15. The main adsorbent 30 includes a porous matrix and a molecularly imprinted polymer loaded on the porous matrix. The molecularly imprinted polymer selectively adsorbs nicotine.

[0030] In this way, the gas stream to be tested enters the filter channel 11 from the inlet 13 of the housing. After the nicotine in the gas stream is adsorbed by the main adsorbent 30, the gas stream to be tested is discharged from the outlet 15. The main adsorbent 30 includes a porous matrix and a molecularly imprinted polymer loaded on the porous matrix. The porous matrix allows the gas stream to be tested to flow through the main adsorbent 30, while the molecularly imprinted polymer loaded on the porous matrix can selectively adsorb nicotine. In this way, the molecularly imprinted polymer specifically adsorbs only nicotine molecules, preventing the adsorption of nicotine coexisting molecules and other interfering molecules, thereby improving the accuracy of nicotine molecule adsorption and subsequent detection precision.

[0031] Understandably, molecularly imprinted polymers (MIPs) are artificially designed highly selective adsorbents. Their preparation process is similar to "molecular molds": using nicotine as a template molecule, a complex is formed with functional monomers through interactions (such as π-π stacking). After polymerization and template elution, a three-dimensional cavity is left in the polymer network that precisely matches the shape, size, and functional groups of the nicotine molecule. This "lock-and-key" structure enables MIPs to specifically recognize and adsorb nicotine, with an adsorption capacity of 5-10 mg / g. Compared to traditional adsorbents, MIPs exhibit 3-5 times higher selectivity for nicotine, effectively eliminating interference from coexisting nicotine components and nicotine structural analogs, thus improving the accuracy of adsorption and detection.

[0032] Furthermore, the molecularly imprinted polymer is constructed as a renewable material. Thus, after the main adsorbent 30 finishes adsorption, it is pulled out of the housing along the axial direction of the filter channel 11, allowing the main adsorbent 30 to be quickly separated from the housing while maintaining the structural integrity of the main adsorbent 30. Subsequently, the molecularly imprinted polymer inside the main adsorbent 30 is regenerated through appropriate treatment.

[0033] Specifically, the regeneration process of molecularly imprinted polymers (MIPs) consists of two key steps: extraction and activation. First, the main adsorbent 30, after adsorbing nicotine, is ultrasonically treated at 40 kHz for 25-35 minutes using 20 mL of methanol solution. The extract is then filtered through a 0.22 μm filter membrane and analyzed by GC-MS or HPLC-MS. Subsequently, a regeneration process is performed, rinsing the adsorbent layer three times with pure methanol at a rate of 50 mL / g of packing material to thoroughly remove residual nicotine and restore π-π interaction sites. The regenerated MIPs material retains over 90% of its initial adsorption capacity and can be reused more than 10 times. This regeneration process, through solvent desorption and site reconstruction, ensures both detection accuracy and maintains the material's selective adsorption performance.

[0034] According to some embodiments of this application, the porous matrix includes at least one of alumina and porous silicon carbide ceramics. That is, the main adsorbent 30 can be a composite structure of alumina and molecularly imprinted polymers (MIPs), with the MIPs loaded onto the porous alumina matrix. Specifically, MIPs can be loaded onto the porous alumina substrate through in-situ polymerization, surface grafting, or physical coating to form a composite adsorbent material. The alumina substrate, with its high mechanical strength (Mohs hardness 9), hierarchical pore structure (macropores 20-50 μm, mesopores 2-50 nm), excellent thermal / chemical stability (resistant to 500℃ high temperature and pH 2-12 environments), and hydrophobic modification properties, not only significantly improves the physical stability and service life of MIPs but also optimizes aerosol mass transfer efficiency, enabling the composite material to achieve a nicotine adsorption capacity of 4-6 mg / g. After 10 regenerations, it retains more than 85% of its adsorption performance, combining cost-effectiveness and practical reliability.

[0035] Alternatively, the main adsorbent 30 can be a composite structure of porous silicon carbide ceramic and molecularly imprinted polymer (MIP), with the MIP loaded onto the porous silicon carbide ceramic. Specifically, MIPs can be loaded onto the porous silicon carbide ceramic substrate through in-situ polymerization or surface grafting to form a high-performance composite adsorbent material. The porous silicon carbide ceramic substrate possesses excellent mechanical strength, high thermal stability, chemical inertness, and a unique three-dimensional interconnected pore structure (pore size adjustable from 1 to 100 μm), which not only provides a robust support framework for the MIPs but also significantly improves mass transfer efficiency and resistance to thermal / chemical shock. This allows the composite material to maintain stable adsorption performance even under harsh environments (e.g., adsorption efficiency >90% after 10 regenerations), making it particularly suitable for selective adsorption and detection of nicotine in high-temperature and corrosive environments.

[0036] See Figure 1 and Figure 2 According to some embodiments of this application, the sampling tube 100 includes a pre-filter 50, which is sleeved within the filter channel 11 and located between the inlet 13 and the main adsorbent 30. The material of the pre-filter 50 is a nanofiber membrane. The pre-filter 50, positioned upstream of the main adsorbent 30 within the filter channel 11, allows the gas flow to be detected from the inlet 13 to undergo preliminary filtration by the pre-filter 50 before flowing to the main adsorbent 30 for nicotine molecule adsorption. In this way, the pre-filter 50 can filter out a portion of particulate matter, preventing excessive particulate matter from flowing into the main adsorbent 30 and clogging it, thus ensuring the flowability of the main adsorbent 30.

[0037] Specifically, the pre-filter 50 is a nanofiber membrane. A nanofiber membrane is an ultrathin porous material prepared by electrospinning of fibers with diameters in the nanoscale (typically 50-500 nm). It has a high specific surface area (up to 100 m² / g), a controllable pore size distribution (10 nm-10 μm), and excellent mechanical flexibility. Its three-dimensional network structure can efficiently intercept particles, for example, it can achieve a retention efficiency of >99.8% for particles with a diameter of 1-5 μm.

[0038] Furthermore, the pre-filter 50 includes at least one of a polyvinylidene fluoride (PVDF) electrospun fiber membrane and an electrospun polyimide membrane. The PVDF electrospun fiber membrane is a nano / micron-scale fibrous network material formed by stretching and curing a PVDF polymer solution under a high-voltage electric field using electrospinning technology. It possesses excellent chemical stability, high thermal stability, and unique piezoelectric properties. Its fiber diameter is typically in the range of 100 nm to 2 μm, and the resulting porous structure (porosity 70%-90%) combines high air permeability with good mechanical strength.

[0039] Electrospun polyimide membranes are nanofiber thin film materials prepared using electrospinning technology, with polyimide as their core component. During preparation, the polyimide solution is stretched into micron or nanoscale fibers under a high-voltage electrostatic field, which are then deposited to form a porous network structure. This material combines the high-temperature resistance, excellent mechanical strength, chemical stability, and insulation properties of polyimide with the high specific surface area, porosity, and flexibility imparted by the electrospinning process, enabling it to effectively filter particulate matter in the airflow being tested.

[0040] According to some embodiments of this application, the sampling tube 100 includes a protective element 70, which seals at least one of the inlet 13 and the outlet 15 while allowing airflow. Thus, by providing the protective element 70 at the inlet 13 and / or outlet 15 of the housing, external moisture and impurities are prevented from entering the filter channel 11 through the inlet 13 and outlet 15, preventing moisture and impurities from entering the main adsorption element 30 and damaging its structure, thereby protecting the main adsorption element 30. Simultaneously, the protective element 70 allows normal airflow; the protective element 70 at the inlet 13 allows the airflow to be tested to flow through the protective element 70 and enter the filter channel 11 for filtration and adsorption, while the protective element 70 at the outlet 15 allows the airflow to be tested to flow out after the nicotine has been filtered and adsorbed.

[0041] Furthermore, the protective component 70 is a droplet blocking layer, and the contact angle of the droplet blocking layer is ≥100°. By setting the protective layer as a hydrophobic droplet blocking layer, droplets can be effectively intercepted, preventing droplets from flowing to the main adsorption component 30 with the detection airflow, preventing droplets from clogging the main adsorption component 30, and further protecting the main adsorption component 30.

[0042] Optionally, the material of the protective component 70 is at least one of silane-modified glass fiber woven layer and polytetrafluoroethylene coated nonwoven fabric, so that the protective component 70 can intercept droplets and impurities, and also allow the airflow to be detected to pass through.

[0043] Silane-modified glass fiber braided layer is a reinforcing material woven from glass fibers after surface treatment with a silane coupling agent. The silane coupling agent introduces hydrophobic groups (such as alkyl chains or fluorocarbon chains) onto the fiber surface through chemical grafting, significantly reducing the surface energy of the material and giving it excellent hydrophobicity. This effectively blocks moisture penetration and reduces the erosion of the fiber-resin interface by environmental moisture. This modification not only improves the hydrophobic properties but also retains the inherent high strength, corrosion resistance, and high porosity of glass fibers. It allows the airflow to be tested to flow through the PTFE-coated nonwoven fabric into the filter channel 11, or allows the airflow to flow through the PTFE-coated nonwoven fabric and out of the filter channel 11, while blocking water vapor and impurities from entering the filter channel 11.

[0044] Polytetrafluoroethylene (PTFE) coated nonwoven fabric is a composite functional material formed by coating the surface of nonwoven fabric with PTFE polymer. PTFE (commonly known as "Teflon") has extremely low surface energy, and its molecular structure features tightly packed fluorine atoms forming a highly hydrophobic, chemically inert surface. This gives the coated nonwoven fabric excellent hydrophobicity—a large contact angle (typically exceeding 110°), making it difficult for water to wet or penetrate, and easily forming water droplets that roll off, thus exhibiting a self-cleaning effect. Furthermore, this material combines the high porosity of nonwoven fabric, allowing the airflow to be detected to pass through the PTFE-coated nonwoven fabric into the filter channel 11, or allowing the airflow to exit the filter channel 11, while preventing water vapor and impurities from entering the filter channel 11.

[0045] Specifically, protective components 70 are provided at both the inlet 13 and the outlet 15 of the housing. The protective component 70 at the inlet 13 intercepts droplets in the airflow to be tested, and the protective component 70 at the outlet 15 can prevent external water vapor and impurities from entering the filter channel 11. In this way, both the inlet 13 and the outlet 15 of the filter channel 11 are protected, thus fully protecting the main adsorption component 30.

[0046] According to some embodiments of this application, the sampling tube 100 includes a nicotine evaporation-preventing layer 80, which is coated on the inner wall of the housing and at least covers the outer surface of the main adsorption element 30. Thus, by coating the inner wall of the housing with the nicotine evaporation-preventing layer 80, nicotine evaporation loss is reduced, improving the accuracy of adsorption and subsequent detection.

[0047] Furthermore, the nicotine evaporation-blocking layer 80 covers at least the outer surface of the main adsorbent 30, which can block nicotine evaporation over a large area and reduce nicotine evaporation loss.

[0048] According to some embodiments of this application, the sampling tube 100 includes a mounting connector 90. The mounting connector 90 is provided at at least one end of the housing having an inlet 13 and an outlet 15. The mounting connector 90 is used for installation and connection with an air extraction component or an air delivery component. Thus, providing the mounting connector 90 at the end of the housing having the inlet 13 facilitates connection of the sampling tube 100 to an air delivery component, which can be a hose or similar component, to deliver the gas flow to be detected into the sampling tube 100 for filtration and adsorption. Alternatively, providing the mounting connector 90 at the end of the housing having the outlet 15 facilitates connection of the sampling tube 100 to an air extraction component, which can be an air pump. The gas flow to be detected flows from the sampling tube 100 to the air extraction component after passing through the main adsorption component 30 inside the housing.

[0049] Furthermore, the mounting connector 90 is integrally injection molded with the housing, facilitating use and eliminating the need for separate assembly of the mounting connector 90, thus simplifying operation. Understandably, in some other embodiments, the mounting connector 90 and the housing can also be molded separately and then assembled together; this is not a limitation. Optionally, the mounting connector 90 is constructed as an annular tube with internal threads, allowing installation of the mounting connector 90 with the air supply or extraction component via a threaded connection.

[0050] In one specific embodiment, the sampling tube 100 includes a shell, two mounting joints 90, two protective members 70, a pre-filter 50, and a main filter. The shell is constructed as a tubular structure with a hollow cavity. Inside the shell, a protective member 70, a pre-filter 50, a main adsorption member 30, and another protective member 70 are arranged sequentially along the axial direction. Mounting joints 90 are provided at both ends of the axial end of the shell. The sampling tube 100 formed in this way can effectively and accurately adsorb nicotine molecules in the gas flow to be detected. At the same time, under the protection of the protective members 70 and the pre-filter 50, the main adsorption member 30 can maintain good flowability and adsorption capacity.

[0051] In addition, the main adsorbent 30 includes a porous matrix and a molecularly imprinted polymer loaded on the porous matrix. The porous matrix allows the gas to be detected to flow through the main adsorbent 30, while the molecularly imprinted polymer loaded on the porous matrix can selectively adsorb nicotine. In this way, the molecularly imprinted polymer specifically adsorbs only nicotine molecules, preventing the adsorption of nicotine coexisting substances and other interfering molecules, thereby improving the adsorption accuracy of nicotine molecules and the subsequent detection precision.

[0052] Understandably, molecularly imprinted polymers (MIPs) are artificially designed highly selective adsorbents. Their preparation process is similar to "molecular molds": using nicotine as a template molecule, a complex is formed with functional monomers through interactions (such as π-π stacking). After polymerization and template elution, a three-dimensional cavity is left in the polymer network that precisely matches the shape, size, and functional groups of the nicotine molecule. This "lock-and-key" structure enables MIPs to specifically recognize and adsorb nicotine, with an adsorption capacity of 5-10 mg / g. Compared to traditional adsorbents, MIPs exhibit 3-5 times higher selectivity for nicotine, effectively eliminating interference from coexisting nicotine components and nicotine structural analogs, thus improving the accuracy of adsorption and detection.

[0053] Furthermore, a pre-filter 50 is installed upstream of the main adsorbent 30 within the filter channel 11. The gas flow to be tested, entering from the inlet 13, undergoes preliminary filtration through the pre-filter 50 before flowing to the main adsorbent 30 for nicotine molecule adsorption. In this way, the pre-filter 50 can filter out a portion of particulate matter, preventing excessive particulate matter from flowing into the main adsorbent 30 and clogging it, thus ensuring the flowability of the main adsorbent 30.

[0054] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A sampling tube, characterized in that, include: A housing, wherein a filter channel is formed within the housing, and the housing has an inlet and an outlet located at opposite axial ends of the filter channel, respectively: and The main adsorption element is fitted inside the filter channel and is fluidly connected between the inlet and the outlet; The main adsorbent comprises a porous matrix and a molecularly imprinted polymer loaded on the porous matrix, wherein the molecularly imprinted polymer selectively adsorbs nicotine.

2. The sampling tube according to claim 1, characterized in that, The molecularly imprinted polymer is constructed as a renewable material.

3. The sampling tube according to claim 1, characterized in that, The porous matrix includes at least one of alumina and porous silicon carbide ceramics.

4. The sampling tube according to any one of claims 1-3, characterized in that, The sampling tube includes a pre-filter, which is fitted inside the filter channel and located between the inlet and the main adsorption element. The material of the pre-filter is a nanofiber membrane.

5. The sampling tube according to claim 4, characterized in that, The pre-filter includes at least one of polyvinylidene fluoride electrospun fiber membrane and electrospun polyimide membrane.

6. The sampling tube according to any one of claims 1-3, characterized in that, The sampling tube includes a protective element that seals at least one of the inlet and the outlet while allowing airflow.

7. The sampling tube according to claim 6, characterized in that, The protective component is a droplet barrier layer, and the contact angle of the droplet barrier layer is ≥100°.

8. The sampling tube according to claim 6, characterized in that, The protective component is made of at least one of silane-modified glass fiber woven layer and polytetrafluoroethylene coated nonwoven fabric.

9. The sampling tube according to any one of claims 1-3, characterized in that, The sampling tube includes a nicotine evaporation-resistant coating, which is applied to the inner wall of the housing and covers at least the outer surface of the main adsorption element.

10. The sampling tube according to claim 1, characterized in that, The sampling tube includes a mounting connector, and the mounting connector is provided at at least one of the two ends of the housing having the inlet and the outlet. The mounting connector is used for installation connection with an air extraction component or an air delivery component.

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