Enrichment and desorption device for organic matter in the C8-C40 volatile range in atmospheric particulate phase

Abstract

The present application provides a device for enriching and desorbing organic matter in the C8-C40 volatile range in the atmospheric particulate phase, comprising: a tube body, a desorption tube, and a transmission tube; the tube body having an inlet and an outlet on either side thereof; a filter membrane, a heating membrane, and a support structure disposed sequentially within the tube body in the direction of the organic matter's injection; a desorption tube having one side welded to the side surface of the tube body and the other side extending radially outward along the tube body; and an L-shaped transmission tube. The device is made of quartz and integrates a quartz fiber filter membrane, a patch-type heating plate, and a quartz support mesh "sandwich" structure. This compact, low-cost device enables direct contact heating of the filter membrane, ensuring uniform, rapid, and precise heating and efficient desorption of organic matter enriched in the quartz filter membrane, thereby avoiding insufficient thermal desorption of C35-C40 high-carbon organic matter.

Description

Technical Field

[0001] The present application belongs to the field of environmental monitoring technology and relates to a device for enriching and desorbing organic matter in the volatility range of C8-C40 in atmospheric particulate phase. Background Art

[0002] Atmospheric organic aerosols are a significant component (20%-50%) of fine particulate matter (PM2.5). The organic matter in these particles is complex in composition, presents low atmospheric concentrations, and exhibits widely varying physical and chemical properties. Currently, only 10% to 40% of the total organic matter mass can be accurately quantified. Atmospheric organic aerosols contain many substances harmful to humans, such as polycyclic aromatic hydrocarbons (PAHs), nitrosamines, and other chlorinated organic compounds, which are carcinogenic, teratogenic, and mutagenic. Organic aerosols also significantly affect atmospheric visibility and are a major contributor to acid deposition and photochemical smog. Furthermore, some organic aerosol compounds serve as important source indicators. For example, polycyclic aromatic hydrocarbons (PAHs) are primarily produced by the incomplete combustion of fossil fuels and biomass; hopanes are biomarkers for fuel oil, coal, and lubricants, and can be used to identify motor vehicle emissions; and n-alkanes can be used as markers of fossil fuel utilization and biogenic emissions. Analysis of these tracers can reveal the source characteristics of particulate matter.

[0003] Organic aerosols, as a significant component of atmospheric fine particulate matter, have significant impacts and hazards on atmospheric climate, the living environment, and human health. Therefore, accurately measuring and characterizing their pollution is a critical step in pollution prevention and control. Currently, the measurement of organic molecular components in particulate matter is primarily conducted through offline and online methods. Offline sampling methods are typically based on membrane samplers or graded impactors such as microporous uniform deposition multi-stage impactors. The sampled components are then taken to the laboratory for a series of offline post-processing steps (including solvent extraction, pre-concentration, and derivatization) and testing. Offline measurements can only identify a limited number of species, and the pre-processing process is complex, with low temporal resolution and inability to reflect real-time changes in atmospheric composition. Online measurement methods offer the advantages of high temporal resolution, automation, labor- and time-saving methods, and real-time analysis of atmospheric composition. These methods primarily include thermal desorption aerosol GC / MS-FID (TAG), chemical ionization mass spectrometry (CIMS), and proton transfer reaction mass spectrometry (PTR-MS).

[0004] Thermal desorption gas chromatography (TDGC), with its advantages of simplicity and high sample utilization, has been used for the determination of trace organic compounds in atmospheric particulate matter. Currently, commercially available equipment is primarily based on the TAG instrument developed by Williams et al. in 2006, primarily used for automated, high-resolution collection and GC-MS analysis of organic compounds in atmospheric particulate matter. Subsequently, various improvements and designs have been made to the TAG pretreatment and separation systems, both domestically and internationally, enhancing its detection and separation performance.

[0005] However, current online collection modules for particulate organic matter are generally based on non-replaceable passivated stainless steel filter membranes or quartz fiber filter membrane enrichment modules made of stainless steel that require internal passivation treatment. The passivation treatment of this collection module generally requires in-house deactivation by Restek Corporation in the United States. This passivation step significantly increases the cost of the equipment and reduces time efficiency. In addition, the current practice of directly enriching the collected organic matter at the head of the chromatographic column or relying solely on temperature for secondary enrichment can significantly cause the penetration of highly volatile C8-C14 substances into the system, thereby losing measurement information on active substances and reducing the richness and comprehensiveness of the instrument's multi-species measurements. Summary of the Invention

[0006] In order to solve the problems in the prior art and expand the monitoring capabilities of highly volatile, low-carbon organic matter collected from particulate matter, the present application provides a quartz-based particulate matter collection system and a dual-focusing system based on adsorbent capture and low-temperature capture, and uses commercial GCMS to separate and detect them, which can expand the particulate matter detection species to the volatility range from C8 to C40. The quartz-based collection component does not require internal passivation pretreatment, reducing the initial preparation time and instrument cost, and uses a patch-type heater closely attached to the quartz filter membrane to contact-heat the enriched filter membrane, ensuring efficient desorption of organic matter. Particulate organic matter species are complex and have a wide boiling point range. High-carbon substances can be captured by low temperature alone due to their high viscosity, while low-carbon C8-C14 substances are more easily lost in the system. To achieve effective measurement of the concentration of highly volatile particulate organic matter, the sampled organic matter is subjected to low-temperature adsorbent focusing, then rapidly heated and desorbed, and finally separated and detected using GCMS. Adsorbent focusing not only expands the range of organic species measured but also avoids subsequent peak tailing. The system's measurement time resolution can be adjusted to varying sampling times based on atmospheric particulate pollution, typically within a range of 30-90 minutes. The entire device is compact and easy to operate, enabling online monitoring of atmospheric particulate organic matter with hourly resolution.

[0007] The technical solution of this application is as follows:

[0008] 1. A device for enriching and desorbing organic matter in the C8-C40 volatility range in atmospheric particulate phase, comprising: a pipe body, a desorption pipe, and a transmission pipe;

[0009] The tube body has an inlet and an outlet on both sides thereof;

[0010] In the direction of the injection of the organic matter, a filter membrane, a heating membrane and a support structure are sequentially arranged inside the tube body;

[0011] a desorption tube, one side of which is welded to the side surface of the tube body, and the other side of which extends radially outward along the tube body;

[0012] The transmission pipe is L-shaped, one side of the transmission pipe is welded to the support structure, wherein one side of the L-shaped transmission pipe extends along the inner wall of the pipe body, and the other side of the L-shaped pipe protrudes from the other side surface of the pipe body opposite to the side surface on which the desorption pipe is welded;

[0013] In the sampling direction of the organic matter, the support structure, the desorption tube and the transmission tube are arranged at different positions of the tube body.

[0014] 2. The enrichment and desorption device according to item 1,

[0015] In the sampling direction of the organic matter, the support mechanism is arranged upstream of the desorption tube, and the transmission tube is arranged downstream of the desorption tube;

[0016] Preferably, the ratio of the distance between the support structure and the desorption tube to the total length of the tube body is (0.3-1):6;

[0017] Further preferably, the ratio of the distance between the support structure and the transmission pipe to the total length of the pipe body is (1-3):6;

[0018] More preferably, the ratio of the distance between the transfer tube and the injection port to the total length of the tube body is (3-4):6.

[0019] More preferably, the ratio of the distance between the desorption tube and the injection port to the total length of the tube body is (1.5-3.5):6.

[0020] 3. The enrichment and desorption device according to item 2,

[0021] In the sampling direction of the organic matter, the desorption tube is arranged upstream of the support mechanism, and the transmission tube is arranged downstream of the support mechanism;

[0022] Preferably, the ratio of the distance between the support structure and the desorption tube to the total length of the tube body is (0.3-1):6;

[0023] Further preferably, the ratio of the distance between the support structure and the transmission pipe to the total length of the pipe body is (1-3):6;

[0024] More preferably, the ratio of the distance between the transfer tube and the injection port to the total length of the tube body is (3-4):6.

[0025] More preferably, the ratio of the distance between the desorption tube and the injection port to the total length of the tube body is (0.5-2.5):6.

[0026] 4. The enrichment and desorption device according to item 1,

[0027] The enrichment and desorption device further comprises an inner liner, which is arranged inside the tube body and between the sample inlet and the filter membrane.

[0028] 5. The enrichment and desorption device according to item 1,

[0029] The enrichment and desorption device further includes a patch temperature sensor, which is located between the filter membrane and the heating membrane and close to the side of the tube body where the transmission tube is located;

[0030] Preferably, the wire connected to the heating diaphragm and the wire connected to the patch temperature sensor are located in the transmission tube.

[0031] 6. The enrichment and desorption device according to item 1,

[0032] The two sides of the tube body are sealed with a first O-ring or a polytetrafluoroethylene ferrule joint. Preferably, the material of the first O-ring is fluororubber or nitrile rubber;

[0033] The desorption tube is sealed with a second O-ring, preferably, the second O-ring is made of polyimide;

[0034] The transmission tube is sealed with a sealant. Preferably, the sealant is made of an inorganic ceramic material.

[0035] 7. The enrichment and desorption device according to item 1,

[0036] The filter membrane is a quartz filter membrane.

[0037] 8. The enrichment and desorption device according to item 1,

[0038] The enrichment and desorption device further comprises a refrigeration unit arranged outside the tube body;

[0039] Preferably, the refrigeration unit is a fan.

[0040] 9. An enrichment and desorption device for organic matter in the volatility range of C8-C40 in atmospheric particulate phase, characterized in that it comprises the enrichment and desorption device described in any one of items 1-8.

[0041] 10. The enrichment and desorption equipment according to item 9, further comprising a high and low temperature component;

[0042] The high and low temperature components include a high temperature module, a low temperature module and a high and low temperature switching module.

[0043] 11. The enrichment and desorption device according to item 10, wherein:

[0044] The high-temperature module includes an adsorption tube and a resistance wire wound around the outside of the adsorption tube, and the adsorption tube is filled with a Tenax series adsorbent;

[0045] Preferably, an insulating sleeve is further provided between the adsorption tube and the resistance wire, and the insulating sleeve is wrapped around the outer periphery of the adsorption tube;

[0046] Further preferably, the high temperature module further comprises a protection unit, and the protection unit is wrapped around the outer periphery of the resistance wire;

[0047] More preferably, the high-temperature module further includes a temperature sensor, which is disposed outside the adsorption tube body and between the insulating sleeve and the adsorption tube.

[0048] 12. The enrichment and desorption device according to item 10, wherein:

[0049] The low-temperature module includes a refrigeration plate and a metal block. The metal block is composed of two symmetrical sub-metal blocks with a semicircular groove at the center and can be opened and closed. The adsorption tube can be fitted in the groove formed by the two symmetrical sub-metal blocks.

[0050] Preferably,

[0051] The cold end of the refrigeration plate is in close contact with the metal block.

[0052] 13. The enrichment and desorption device according to item 10, wherein:

[0053] The high and low temperature switching module includes a pneumatic drive device, which realizes the switching of the adsorption tube between the high temperature mode and the low temperature mode by separating and closing the low temperature sub-metal block;

[0054] Preferably,

[0055] When the carrier gas is introduced into the pneumatic drive device, the two symmetrical sub-metal blocks move relative to each other, so that there is a gap between the two symmetrical sub-metal blocks and the adsorption tube, and the heating module is controlled to operate in a high-temperature mode;

[0056] When the pneumatic device does not pass the carrier gas, the two symmetrical sub-metal blocks move toward each other so that the two symmetrical sub-metal blocks are attached to the adsorption tube, and the heating module is controlled to stop working and enter the low-temperature mode.

[0057] 14. A method for using the enrichment and desorption device described in any one of items 1 to 8 or the enrichment and desorption equipment described in any one of items 9 to 13 for online measurement of organic matter in the volatility range of C8-C40 in atmospheric particulate phase.

[0058] 15. The method according to claim 14, comprising:

[0059] Sampling step, purging step, focusing and enrichment step, and measurement step; wherein,

[0060] Sampling step: passing the sample to be tested into the enrichment and desorption device so that the organic matter in the particle phase is enriched in the enrichment and desorption device;

[0061] Purging step: purging the enrichment and desorption device and its transmission route or the enrichment and desorption equipment and its transmission route with carrier gas to remove excess gas;

[0062] Focusing on the enrichment step: desorbing the organic matter in the particle phase adsorbed in the enrichment and desorption device and entering the enrichment and desorption equipment;

[0063] Measurement steps: desorb the particle phase organic matter adsorbed on the enrichment and desorption equipment, and separate and measure the particle phase organic matter.

[0064] Compared with the prior art, the present invention has the following advantages:

[0065] (1) The quartz fiber filter membrane particulate matter enrichment thermal desorption module based on the quartz medium as the carrier of the present application integrates the quartz fiber filter membrane-patch type heating plate-quartz support net "sandwich" structure into one, and nests it in the quartz tube. This not only avoids the previous step of additional passivation pretreatment inside the stainless steel medium, but also reduces the instrument development time and equipment cost to a certain extent. In addition, the "sandwich" type enrichment thermal desorption structure can achieve direct contact heating of the filter membrane. Unlike the current heating method of heating the quartz tube and then transmitting it to the filter membrane, this contact heating can ensure that the organic matter enriched in the quartz filter membrane is quickly and accurately heated and efficiently analyzed, avoiding the phenomenon of insufficient thermal desorption of C35-C40 high-carbon organic matter.

[0066] (2) In order to expand the measurement of low-carbon substances in particulate organic matter, a dual focusing module based on adsorbent enrichment and low-temperature enrichment was designed after filter membrane sampling. The C8-C14 low-carbon organic matter that is easy to lose is enriched with adsorbent at low temperature to ensure that it can enter the GCMS module without loss. The focusing module adopts pneumatic control to quickly switch the low-temperature enrichment and high-temperature desorption of organic matter, avoiding the temperature ambiguity phenomenon of high and low temperature conversion, and can meet the temperature range requirements of -40℃ to 320℃. This not only expands the monitoring range of the system, but the instantaneous temperature rise desorption also avoids the peak tailing phenomenon of subsequent sample peaks.

[0067] (3) The entire equipment's gas path switching relies solely on an electrically passivated three-way ball valve and an electrically powered three-way valve at the front end of the gas path, eliminating the need for high-temperature four-way or six-way valves that are prone to wear and leakage. The entire equipment is compact and has a small design. Each component can be designed as a separate modular system. The system has a time resolution of 30-90 minutes, enabling online measurement of atmospheric particulate organic matter with hourly resolution.

[0068] (4) According to the physicochemical properties of atmospheric particulate organic matter, the independently designed quartz medium thermal desorption enrichment-adsorbent low-temperature double focusing technology module is used, combined with gas chromatography-mass spectrometry, control system and data processing software system, to achieve online measurement of the molecular level concentration of organic matter in the C8-C40 volatility range in the atmospheric particulate phase, forming a high-sensitivity online measurement system for low-concentration atmospheric particulate phase organic matter.

[0069] (5) The enrichment and desorption device in the present application adopts a direct heating method that can heat the filter membrane efficiently and centrally, with little impact on the temperature of the tube body, so that the temperature of the sample inlet and outlet on both sides of the tube body is as low as below 50°C. Ordinary O-rings or compression fittings can be used for sealing, saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 Schematic diagram of the enrichment and desorption device for organic matter in the volatile range of C8-C40 in the atmospheric particulate phase;

[0071] Figure 2 Schematic diagram of the enrichment and desorption device for organic matter in the volatile range of C8-C40 in the atmospheric particulate phase;

[0072] Figure 3 Schematic diagram of high and low temperature components in the enrichment and desorption equipment for organic matter in the C8-C40 volatile range in the atmospheric particulate phase;

[0073] Figure 4 Schematic diagram of the enrichment and desorption equipment for organic matter in the volatile range of C8-C40 in the atmospheric particulate phase;

[0074] Figure 5 The chemical composition and signal value result diagram of atmospheric particulate organic matter collected by the online particulate organic matter enrichment monitoring device system described in this application;

[0075] Reference numerals:

[0076] 19: Cutting head, 20: Etcher, 21: First electric three-way valve, 22: Particle enrichment and desorption device, 23: Second electric three-way valve, 24: Adsorption focusing trap device or high and low temperature component, 25: Third electric three-way valve, 26: Electric ball valve, 27: Electronic pressure controller, 28: GCMS, 29: Mass flow controller, 30: Air pump, 31: Air supply and air line pressure control system, 32: Computer interactive control system; 1: Aluminum protective shell, 2: Insulation cotton, 3: Copper block, 4: Refrigeration plate, 5: Resistance wire, 6: Adsorption tube, 7: Glass fiber cotton, 8: Thick-walled quartz tube, 9: connecting screws, 10: low-temperature temperature sensor, 11: finger platform cylinder, 12: stainless steel connecting column, 13: support rod, 14: thermal insulation pad, 15: insulating sleeve, 16: adsorbent, 17: temperature sensor, 18: stainless steel screws; 33: quartz glass tube, 34: thin-walled quartz lining, 35: quartz fiber filter membrane, 36: patch-type heating diaphragm, 37: quartz support structure, 38: desorption quartz tube, 39: patch-type temperature sensor, 40: quartz transmission tube, 41: O-ring, 42: inorganic adhesive sealant, 43: stainless steel screws. DETAILED DESCRIPTION

[0077] At present, online collection devices for particulate organic matter at home and abroad generally use 316 stainless steel as the carrier medium of the filter membrane. Since particulate organic matter is very easy to adhere to the surface of stainless steel, the online collection device must be passivated and pre-treated internally during actual use. However, the current domestic passivation treatment technology is still immature. Generally, the enrichment and desorption module must be taken to the American Restek company for inner wall passivation. This operation will undoubtedly increase the equipment cost and equipment production time. Based on this shortcoming, the present applicant independently developed a particulate matter enrichment and desorption device based on quartz material as the filter membrane support carrier. In this device, a filter membrane-heating membrane-support structure "sandwich" structure is integrated, such as a quartz fiber filter membrane-patch type heating membrane-quartz support structure "sandwich" structure, which is nested in a quartz pipe to form an integrated device for collecting and desorbing atmospheric particulate matter. The support body made of quartz does not require internal passivation pretreatment. Unlike the structural design of the existing heating device in which the external heating rod and temperature sensor are a certain distance away from the sampling filter membrane, the patch-type heating membrane used in this application directly heats the quartz filter membrane in contact, and the patch-type temperature sensor is placed between the heating membrane and the quartz filter membrane. This design can not only achieve rapid heating and thermal analysis of the filter membrane, but also read the actual temperature at the quartz filter membrane in real time, ensuring rapid heating and efficient analysis of organic matter enriched in the quartz filter membrane, and avoiding insufficient thermal desorption of C35-C40 high-carbon organic matter.

[0078] At present, the pretreatment device of particulate organic matter generally performs thermal desorption on the collected organic matter and then sends it directly to the GC for enrichment at the head of the chromatographic column. This method can easily lead to the penetration and loss of C8-C14 organic matter, and due to the high gas resistance of the chromatographic column and the limited flow rate that the chromatographic column and mass spectrometer can withstand, the thermal desorption flow rate is limited, resulting in incomplete thermal desorption of low-volatile organic matter. In order to expand the collection and measurement of particulate low-carbon organic matter, the present application designs a small focusing module with a simple structure and easy operation for low-temperature and adsorbent dual enrichment after filter membrane sampling. The device can not only perform low-temperature enrichment of low-carbon organic matter that is easy to lose with adsorbent, but also re-capture high-carbon organic matter through simple low-temperature control, ensuring that it can subsequently enter the GCMS module without loss, reducing the tailing phenomenon of the material peak. The focusing module adopts pneumatic control to quickly switch the low-temperature enrichment and high-temperature analysis of organic matter, avoiding the temperature ambiguity phenomenon of high and low-temperature temperature conversion, and can meet the temperature switching requirements from -40℃ low-temperature enrichment to 320℃ high-temperature desorption. The focusing module is small in size and compact in structure, which not only expands the monitoring range of the system, but the instantaneous desorption temperature rise can also avoid the peak tailing phenomenon of subsequent sample peaks.

[0079] Organic matter in the atmospheric particle phase with a volatility range of C8-C40 (abbreviated as particle phase organic matter) refers to organic matter in the form of particles in the atmosphere, generally referring to organic matter with an effective saturated vapor concentration of 10 -1 ~10 6 μg·m -3 A large class of substances in the range of C8-C40 whose saturated vapor pressure corresponds to saturated alkanes in the range of C8-C40.

[0080] In addition, existing devices generally use electric four-way or six-way valves to switch the gas path, which is reasonable in principle. However, in actual operation, it is found that the electric four-way or six-way valves in the particulate gas path switching system are prone to valve core wear, resulting in system leakage, and the valve core needs to be replaced basically every month. To address this phenomenon, this application uses a commercial electric three-way ball valve based on pulse control as the gas path switching component, which can reduce maintenance and costs during the later use of the instrument to a certain extent.

[0081] like Figure 1 As shown, the present application provides an enrichment and desorption device for organic matter in the volatility range of C8-C40 in the atmospheric particulate phase, including: a tube body 33, a desorption tube 38 and a transmission tube 40; the tube body 33, the two sides of the tube body are respectively an inlet and an outlet; in the sampling direction of the organic matter, a filter membrane 35, a heating membrane 36 and a support structure 35 are sequentially arranged inside the tube body; the desorption tube 38, one side of which is welded to the side surface of the tube body 33, and the other side thereof extends radially outward along the tube body 33; the transmission tube 40, the transmission tube 40 is L-shaped, and one side of the transmission tube 40 is welded to the support structure 35, wherein one edge of the L-shaped transmission tube extends along the inner wall of the tube body 33, and the other edge of the L-shape protrudes from the other side surface of the tube body 33 opposite to the side surface on which the desorption tube 38 is welded; in the sampling direction of the organic matter, the support structure 35, the desorption tube 38 and the transmission tube 40 are arranged at different positions of the tube body 33. This design ensures that only local heating of the filter membrane is performed, so that the temperature of the sample inlet and the gas outlet is no higher than 50°C. When sealing the sample inlet and the gas outlet, only ordinary O-rings are used for sealing, which saves costs.

[0082] In one embodiment of the present application, the tube body 33 is a quartz glass tube body, the desorption tube 38 is a quartz desorption tube, the transmission tube 40 is a quartz transmission tube, the filter membrane 35 is a quartz fiber filter membrane, the heating membrane 36 is a patch-type heating membrane, and the support structure 35 is a quartz support net. The device is based on a quartz material as the main frame and a "sandwich" structure composed of a quartz fiber filter membrane-patch-type heating membrane-quartz support net as a particulate organic matter collection and desorption device. The device is made of quartz and only requires simple wall cleaning (alcohol or distilled water ultrasound, high temperature baking), and does not need to be sent abroad for surface passivation treatment, which reduces the initial preparation time and cost of the instrument to a certain extent. In addition, the developed quartz fiber filter membrane-patch-type heating membrane-quartz support net "sandwich" structure can realize direct heating of the filter membrane and accurate control and reading of real-time temperature, ensuring the rapid thermal desorption temperature requirements and high-efficiency analysis efficiency of C8-C40 high-carbon substances.

[0083] like Figure 1 As shown, the enrichment and desorption device further includes an inner liner 34, which is disposed within the tube body and between the sample inlet and the filter membrane 35. Liner 34 is placed between the quartz fiber filter membrane 35 and the sample inlet of the quartz glass tube to protect the filter membrane 35 from positional movement caused by airflow. Liner 34 can be a thin-walled quartz liner, with dimensions compatible with the thin-walled quartz glass tube body 33.

[0084] like Figure 1 As shown, the enrichment and desorption device also includes a patch temperature sensor 39, which is located between the filter membrane and the heating membrane, and close to the side of the tube body with a transmission tube; preferably, the wire connected to the heating membrane and the wire connected to the patch temperature sensor are located in the transmission tube. In order to monitor the temperature of the sampling quartz fiber filter membrane in real time, the patch temperature sensor 39 is set between the quartz fiber filter membrane 35 and the patch heating membrane 36, and close to the side of the tube body with a transmission tube. It can accurately obtain the actual temperature of the sampling filter membrane, ensuring that the quartz fiber filter membrane 35 can reach the accurate thermal desorption temperature during the thermal desorption stage, thereby ensuring the efficient desorption efficiency of high-carbon substances. The circuit connection wires of the patch heating membrane 36 and the patch temperature sensor 39 are wrapped with a layer of high-temperature resistant quartz glass fiber protective cover to avoid unnecessary interference of the circuit connection wires with the sampling airflow, thermal desorption airflow or subsequent detection during actual high-temperature operation.

[0085] like Figure 1 As shown, in the sampling direction of the organic matter, the supporting mechanism is arranged upstream of the desorption tube, and the transmission tube is arranged downstream of the desorption tube.

[0086] like Figure 1As shown, the ratio of the distance between the support structure and the desorption tube to the total length of the tube is (0.3-1):6. In this case, the distance between the support structure and the desorption tube refers to the distance between the two in a direction parallel to the tube. The ratio of the distance between the support structure and the desorption tube to the total length of the tube is (0.3-1):6, which allows the support structure to maintain a certain distance from the sample inlet of the tube to avoid excessive temperatures at the sample inlet of the tube during heating of the filter membrane, resulting in poor sealing. The distance between the support structure and the desorption tube is small, minimizing the gas transmission process of the analyzed substance.

[0087] like Figure 1 As shown, the ratio of the distance between the support structure and the transfer tube to the total length of the tube is (1-3):6. Here, the distance between the support structure and the transfer tube refers to the distance between them in a direction parallel to the tube. This ratio of the distance between the support structure and the transfer tube to the total length of the tube is (1-3):6. This structure ensures that during the high-temperature desorption stage, the transfer tube does not affect the desorption of substances concentrated on the filter membrane at the support structure.

[0088] like Figure 1 As shown, the ratio of the distance between the transmission tube and the injection port to the total length of the tube body is (3-4):6; at this time, the distance between the transmission tube and the injection port refers to the distance between the two in the direction parallel to the tube body, which can ensure that the transmission tube has no effect on the sampling airflow during the sampling stage.

[0089] like Figure 1 As shown, the ratio of the distance between the desorption tube and the injection port to the total length of the tube body is (1.5-3.5):6; at this time, the distance between the desorption tube and the injection port refers to the distance between the two in the direction parallel to the tube body. This design simplifies the sampling and desorption gas paths.

[0090] like Figure 2 As shown, in the injection direction of the organic matter, the desorption tube is arranged upstream of the support mechanism, and the transmission tube is arranged downstream of the support mechanism; preferably, the ratio of the distance between the support structure and the desorption tube to the total length of the tube body is (0.3-1):6; further preferably, the ratio of the distance between the support structure and the transmission tube to the total length of the tube body is (1-3):6; more preferably, the ratio of the distance between the transmission tube and the injection port to the total length of the tube body is (3-4):6, more preferably, the ratio of the distance between the desorption tube and the injection port to the total length of the tube body is (0.5-2.5):6, and the rest are Figure 1 The structures shown are the same.

[0091] like Figure 1As shown, the tube body is sealed on both sides with a first O-ring or a PTFE ferrule, preferably made of fluororubber or NBR. The desorption tube is sealed with a second O-ring, preferably made of high-temperature-resistant polyimide. The transfer tube is sealed with a sealant, preferably made of inorganic ceramic. Fluororubber, NBR, or PTFE ferrule first O-rings are both resistant to 150°C and are readily available. The high-temperature-resistant polyimide second O-ring must withstand 350°C and is currently only available through import from Agilent.

[0092] In some embodiments of the present application, the enrichment and desorption device further comprises a refrigeration unit disposed outside the tube body; preferably, the refrigeration unit is a fan. The fan can cool the quartz filter membrane. The fan is placed outside the quartz main tube corresponding to the quartz filter membrane. When cooling is required, the fan operates to cool the quartz filter membrane.

[0093] In the embodiments of the present application, the size of the tube body can be selected according to actual conditions.

[0094] like Figure 1As shown, in the sampling direction of the organic matter, the support structure is arranged upstream of the desorption tube, and the transmission tube is arranged downstream of the desorption tube; the desorption tube is 0.3 cm downstream of the support structure. The enrichment and desorption device is primarily made of quartz, which does not require internal passivation treatment. The enrichment and desorption device tube 33 is 1 / 2 inch in diameter and 6 cm long, and is made of quartz glass tube. A quartz support structure 37 is welded 2 cm upstream of the sample inlet of the quartz glass tube 33 to support and protect the sampling quartz filter membrane and other components. A patch-type heating membrane 36 corresponding to the size of the 1 / 2-inch quartz glass tube 33 is placed above the quartz support structure 37. A heating wire with a certain resistance value is deployed inside the heating membrane 36. The heating voltage is 24V and the heating power is 80W. The heating membrane can achieve rapid heating requirements from 30°C to 320°C. A high-purity quartz filter membrane 35 with high particle retention rate, low background value, and high temperature resistance is selected as the actual particulate matter sampling component. The quartz fiber filter membrane 35 is 1 / 2 inch in size and is placed close to the patch-type heating membrane 36. The larger filter membrane provides sufficient surface area for particulate matter sampling. In actual operation, the quartz filter membrane 35 can be replaced with tweezers. In addition, in order to prevent the long-term thermal desorption airflow from causing the filter membrane to move during the thermal desorption stage, a 3 / 8-inch thin-walled quartz lining 34 is placed between the quartz fiber filter membrane 35 and the sampling port of the quartz glass tube body 33 to protect the filter membrane from moving due to airflow transmission. In order to monitor the temperature at the sampling filter membrane in real time, a patch temperature sensor 39 is placed between the quartz fiber filter membrane 35 and the patch heating membrane 36 and close to the side of the quartz transmission tube 40. It can accurately monitor the actual temperature at the sampling filter membrane, ensure that the quartz fiber filter membrane 35 can reach the accurate thermal desorption temperature of 320°C during the thermal desorption stage, and ensure the desorption efficiency of C35-C40 high-carbon organic matter. The circuit connecting wires of the patch-type heating diaphragm 36 and the patch-type temperature sensor 39 are wrapped in a high-temperature resistant quartz glass fiber protective sheath. To further prevent unnecessary interference of the circuit connecting wires with the sampling airflow, thermal desorption airflow, or subsequent testing during actual high-temperature operation, a quartz transmission tube 40 with a diameter of 3 mm is welded below the quartz support structure 37. A hole is opened 4 cm below the quartz glass tube 33, and the lead-out length is 2 cm. This 3 mm quartz transmission tube 40 is used to accommodate the circuit connecting wires of the patch-type heating diaphragm 36 and the patch-type temperature sensor 39. The end of the quartz transmission tube 40 is sealed with sealant 42 to prevent air leakage. In actual application, when the quartz fiber filter 35 is at the high-temperature thermal desorption temperature of 320°C, the temperature of the sealant 42 is actually only 40°C.

[0095] like Figure 2As shown, in the sampling direction of the organic matter, the desorption tube is arranged upstream of the support mechanism, and the transmission tube is arranged downstream of the support mechanism; the desorption tube is 0.3 cm upstream of the support structure. The diameter of the enrichment and desorption device tube 33 is 1 / 2 inch and 6 cm long. It is made of quartz glass tube. A quartz support structure 37 is welded 2 cm upstream of the sample inlet of the quartz glass tube 33. A patch-type heating membrane 36 corresponding to the size of the 1 / 2 inch quartz glass tube 33 is placed above the quartz support structure 37. A heating wire with a certain resistance value is deployed inside the heating membrane 36. The heating voltage is 24V and the heating power is 80W. The heating membrane can achieve rapid heating from 30°C to 320°C. A quartz transmission tube 40 with a diameter of 3mm is welded below the quartz support structure 37 and is led out from a hole 4 cm below the quartz glass tube 33. The lead-out length is 2 cm. The 3mm quartz transmission tube 40 can be used to place the circuit connection wires of the patch-type heating membrane 36 and the patch-type temperature sensor 39. The tail end of the quartz transmission tube 40 is sealed with sealant 42 to prevent air leakage. The rest of the structure is the same. Figure 1 The structure described.

[0096] To transfer the desorbed material to subsequent components, a 1 / 16-inch hole is drilled immediately below the lower end of the quartz support structure 37 and a 1 / 16-inch desorption quartz tube 38 is welded to it. This tube 38 is used to transfer the desorbed material to the subsequent passivation three-way ball valve. Both are sealed with a commercial, high-temperature-resistant polyimide O-ring 41. Furthermore, to ensure effective sealing between the upper and lower ends of the quartz glass tube 33 and the stainless steel, commercial O-rings are also used to seal the subsequent electric three-way valve.

[0097] In one embodiment of the present application, the main function of the particulate matter enrichment and desorption device is to use the quartz fiber filter membrane 35 to sample and intercept particulate phase organic matter at 30°C, and then quickly heat it to 320°C to desorb the organic matter deposited on the quartz fiber filter membrane 35 at high temperature. Therefore, real-time and accurate reading of the quartz fiber filter membrane 35 and high and low temperature control are crucial. The present application uses a large air volume vortex fan set on the outside of the tube body to quickly cool down the quartz fiber filter membrane 35. Since the quartz fiber filter membrane 35 is small in size and the quartz glass tube body 33 is a thin-walled tube, it can be quickly cooled. The high temperature of the quartz fiber filter membrane 35 is achieved by using a patch-type heating membrane 36 with an 80W heating power that is close to the quartz fiber filter membrane 35. Since the heating power is large and the heating components are small and more concentrated, the patch-type heating membrane 36 can be quickly heated. The device's temperature is read using a patch-type temperature sensor 39 placed between the quartz fiber filter 35 and the patch-type heating membrane 36. Because it is positioned in close proximity to the quartz fiber filter 35, it can accurately obtain the real-time temperature at the quartz fiber filter 35. The device's temperature is controlled by a Siemens programmable logic controller (PLC) using a PID algorithm.

[0098] The present application also provides an enrichment and desorption device for organic matter in the volatility range of C8-C40 in the atmospheric particulate phase, including the above-mentioned enrichment and desorption device and high and low temperature components.

[0099] like Figure 3 As shown, the high and low temperature components include a high temperature module, a low temperature module and a high and low temperature switching module.

[0100] like Figure 3 As shown, the high-temperature module includes an adsorption tube 6 and a resistance wire 5 wrapped around the outside of the adsorption tube, and the adsorption tube 6 is filled with Tenax series adsorbent; there is also a layer of insulating sleeve 53 between the adsorption tube and the resistance wire, and the insulating sleeve 53 is wrapped around the outer periphery of the adsorption tube 6.

[0101] The high temperature module further includes a protection unit 15 , which is wrapped around the outer periphery of the resistance wire 5 ; the high temperature module further includes a temperature sensor 42 , which is arranged outside the adsorption tube body 6 and between the insulating sleeve 53 and the adsorption tube 6 .

[0102] like Figure 3 As shown, the adsorption tube body is made of 316 stainless steel or German Schott-Duran high-precision quartz glass. When this adsorption tube body is selected, the gas flow rate range can be controlled within 0.05-2L / min.

[0103] like Figure 3As shown, a thick-walled quartz tube 8 is provided near the gas outlet of the strong adsorbent. The thick-walled quartz tube 8 is used to protect the adsorbent to avoid loss of the adsorbent due to long-term sampling.

[0104] like Figure 3 As shown, the adsorption tube also includes a heating unit 5, which is a resistance wire wound around the outside of the adsorption tube body. The resistance wire is wound around the outer wall of the adsorption tube body; preferably, the resistance wire is a nickel-chromium resistance wire, which can heat the adsorption tube body to 50-350°C to provide high temperature for analysis.

[0105] like Figure 3 As shown, a layer of insulating sleeve 53 is also included between the adsorption tube and the heating unit 5, and the insulating sleeve 53 is wrapped around the outer periphery of the adsorption tube body; preferably, the material of the protective sleeve is selected from one or more of alkali-free glass fiber, quartz fiber, and high silica, and the insulating sleeve is used to prevent the resistance wire from aging due to long-term use, thereby causing a short circuit between the resistance wire and the stainless steel adsorption tube.

[0106] like Figure 3 As shown, the adsorption tube further includes a protective unit 15, which is wrapped around the outer periphery of the heating unit; preferably, the protective unit is made of glass fiber. The protective unit 15 acts as a protective sleeve, wrapped around the outer periphery of the resistance wire 5, to prevent wear of the resistance wire 5 caused by the impact and clamping action between the resistance wire 5 and the refrigeration metal block, thereby protecting the heating unit 5.

[0107] like Figure 3 As shown, the adsorption tube 6 also includes a temperature sensor 17, which is arranged outside the adsorption tube body and between the insulating sleeve and the adsorption tube body 6, and is used to display the temperature of the adsorbent. The temperature sensor 17 is close to the outer wall of the adsorption tube and can more realistically display the real-time temperature of the adsorbent to reduce the insufficient enrichment and analysis of organic matter caused by temperature discrimination. The external PID control system is used to control the temperature of the adsorbent at + 0.1℃, ensuring the temperature accuracy of the adsorbent itself.

[0108] like Figure 3 As shown, the low-temperature module includes a cooling plate and a metal block. The metal block is composed of two symmetrical sub-metal blocks with a semicircular groove at the center. The adsorption tube can be placed in the groove formed by the two sub-metal blocks. The high-temperature module also includes a protection unit 15. The low-temperature module also includes cooling plastic screws, a temperature sensor, and a heat dissipation unit.

[0109] The low-temperature module in the high-low temperature component includes two low-temperature temperature modules and a high-low temperature switching module. The two low-temperature temperature modules are symmetrically arranged relative to each other, and are connected and fixed to the finger platform cylinder 11 through a stainless steel connecting column 12 to provide constant enriched low temperature for the adsorption tube; the pneumatic drive device is connected to the two low-temperature temperature modules, and the pneumatic drive device can drive the two low-temperature temperature modules to move toward or in opposite directions in the longitudinal direction. When the two low-temperature temperature modules move toward each other and are in contact, they can tightly clamp the adsorption tube. When the two low-temperature temperature modules move in opposite directions and are separated, they can release the adsorption tube.

[0110] The low-temperature module includes a cooling fin 4, a metal block 3, plastic screws, a temperature sensor, and a heat sink. The cooling fin is a three-stage semiconductor refrigeration element capable of lowering the adsorption tube temperature to -40°C, providing a continuous low temperature. The metal block 3, for example, a copper block with a low specific heat capacity, serves as the heat transfer medium. The metal block consists of two symmetrical sub-metal blocks with a semicircular groove in the center that can be opened and closed. The adsorption tube fits snugly in the groove formed by the two sub-metal blocks. The two sub-metal blocks are symmetrically arranged relative to each other to form the low-temperature module.

[0111] The cold end of the cooling fin 4 is tightly attached to the metal block 3. The metal block 3 is tightly mounted to the cold end of the cooling fin via a layer of thermal grease. The hot end of the cooling fin 4 can be connected to a copper tube radiator and a cooling fan via another layer of thermal grease. The copper tube radiator is used to dissipate heat from the cooling fin, utilizing the excellent thermal conductivity of the copper tube and the condensation conversion of the liquid within the copper tube to output heat to the cooling fan. One side of the copper tube radiator is connected to the hot end of the cooling fin 4 via a layer of thermal grease; the other side is connected to the cooling fan via its own button screws. A thin-walled aluminum protective shell is placed on the outer layer of the metal block 3. Insulating cotton is tightly mounted between the metal block 3 and the aluminum protective shell. The metal block is connected to the aluminum protective shell via plastic screws.

[0112] In a specific embodiment of the present application, Figure 2As shown, the low-temperature module is composed of two symmetrical sub-low-temperature modules. The sub-modules are controlled by a pneumatic drive device to separate or close, thereby realizing the rapid switching function of the adsorption tube between high and low temperatures. The sub-temperature module uses a copper block 3 with a low specific heat capacity as a heat-conducting medium. The size of the copper block 3 is 130mm*30mm. A semicircular groove corresponding to the outer diameter of the adsorption tube is opened at the center of the copper block 3. The adsorption tube 6 is placed in the circular groove, which can wrap the adsorption tube seamlessly when the sub-temperature module is closed, thereby realizing temperature transfer. In order to reduce the temperature loss of the copper block 3, an aluminum protective shell 1 is added to its outside. The size of the aluminum protective shell 1 is 140*33mm. The aluminum protective shell 1 and the copper block 3 are connected using M4*12 PTFE screws 9. The gap between the two is filled with thermal insulation cotton 2 to reduce the temperature transmission loss of the sub-temperature module and the air. A support rod 13 is used to fix and connect the adsorption tube 6. The lower end of the support rod is connected to the workbench via an insulating pad 14 to reduce temperature transmission losses. The upper end of the support rod 13 is connected to the adsorption tube 6 via an M4*16 stainless steel screw 43, thereby supporting and fixing the adsorption tube 6. The temperature sensor 10 of the low-temperature module is placed at the side opening of the copper block 3, that is, the side opening between the copper block 3 and the aluminum protective shell 1 is opened, and its size is adapted to the outer diameter (4mm) of the low-temperature temperature sensor 10. The low-temperature temperature sensor 10 is placed inside the aluminum block 3 to display the actual temperature of the aluminum block 3 in real time. Under normal circumstances, the temperature at the low-temperature module is controlled to remain unchanged at -40°C.

[0113] The high-temperature module of the present application, that is, the heating unit of the adsorption tube is mainly heated by the DC voltage of the resistance wire 5. The resistance wire is evenly and tightly wound on the outer wall of the adsorption tube. In order to avoid the phenomenon of leakage short circuit caused by mechanical impact of the resistance wire caused by the low-temperature module clamping the adsorption tube during low-temperature transmission, a layer of insulating protective sleeve is wrapped around the outer wall of the adsorption tube with the wound resistance wire. The material of the protective sleeve is glass fiber cotton, which can prevent the resistance wire from short circuiting and will not interfere with the low-temperature transmission. The heating temperature can be increased from -40°C to 320°C within 4s; the resistance wire is heated only when the adsorption tube requires high temperature, and is not heated at other times.

[0114] The low-temperature module of the present application, that is, the refrigeration is achieved by a three-stage semiconductor refrigeration element 4 at a low temperature of -40°C. Since the temperature module is relatively small in size, the use of a three-stage refrigeration plate can make the temperature control module as a whole at a constant low temperature of -40°C. The cold end of the refrigeration plate 4 is installed on the copper block 3 on the other side of the semicircular groove end, and the two are tightly connected by thermal conductive silicone grease. The hot end of the refrigeration plate 4 can be connected to the copper tube radiator through another thermal conductive silicone grease layer to ensure the efficient operation of the refrigeration plate. The refrigeration plate is always in the refrigeration working state after being turned on, and the low temperature is displayed in real time by the temperature sensor 10, that is, it is ensured that the sub-temperature module is always at a constant temperature of -40°C, so as to quickly transfer the low temperature to the adsorption tube at any time.

[0115] The high-low temperature switching module includes a pneumatic drive device, which controls the opening or closing of the low-temperature sub-metal block by controlling the flow of carrier gas, thereby ultimately switching the adsorption tube between the high-temperature mode and the low-temperature mode;

[0116] When carrier gas is introduced into the pneumatic drive device, the two symmetrical sub-metal blocks move relative to each other in the longitudinal direction and separate. At this time, the two symmetrical sub-metal blocks open, so that there is a gap between the two symmetrical sub-metal blocks and the adsorption tube, the heating module is controlled to work, and the adsorption tube is in high-temperature mode; when no carrier gas is introduced into the pneumatic device, the two symmetrical sub-metal blocks move toward each other in the longitudinal direction. At this time, the two symmetrical sub-metal blocks close, so that the two symmetrical sub-metals clamp the adsorption tube, the heating module is controlled to stop working, and the adsorption tube is in low-temperature mode.

[0117] The switch between high temperature mode and low temperature mode is mainly achieved by controlling the pneumatic drive device to keep the adsorption tube in high temperature and low temperature state, as follows:

[0118] like Figure 3 As shown, the pneumatic device includes a micro-finger platform cylinder, a two-position five-way valve, a PU pneumatic high-pressure pipe and a high-pressure air source. The micro-finger platform cylinder is connected to the bottom of the two sub-metal blocks through a stainless steel connecting column. The air inlet and the air outlet of the micro-finger platform cylinder are respectively connected to the working port of a two-position five-way valve. The air inlet of the two-position five-way valve is connected to the high-pressure air source, and the two exhaust ports of the two-position five-way valve are connected to the muffler. The micro-finger platform cylinder can drive the two semi-metal blocks to move toward or in opposite directions along the longitudinal direction through the drive of the two-position five-way valve and the high-pressure air source, thereby controlling the opening or closing of the temperature module as a whole to achieve the requirement of converting the adsorption tube from low temperature to high temperature;

[0119] The axial opening and closing movement of the micro-finger platform cylinder 11 is controlled by a pneumatic drive device to achieve the switching of the high and low temperatures of the adsorption tube. Specifically, when the adsorption tube 6 needs to work under high temperature conditions, the pneumatic device controls the micro-finger platform cylinder 11 to open axially, driving the two sub-metal blocks to separate, thereby releasing the adsorption tube 6, that is, at this time there is a gap between the adsorption tube 6 and the two metal blocks, and the resistance wire wrapped around the outer wall of the adsorption tube 6 is controlled to work, heating the adsorption tube to the required high temperature, and the adsorption tube 6 is in high temperature mode; when the adsorption tube 6 needs to work under low temperature conditions, the resistance wire is controlled to stop heating, and the pneumatic device controls the micro-finger platform cylinder 11 to close axially, thereby driving the two sub-metal blocks to close and clamp the adsorption tube, and the low temperature of the two sub-metal blocks is transferred to the adsorption tube, thereby realizing the low temperature conversion, and the adsorption tube 6 is in low temperature mode.

[0120] At present, the measurement device of particulate organic matter generally performs thermal desorption on the collected organic matter and then sends it directly to the GC for enrichment at the head of the chromatographic column. The temperature enrichment alone can easily lead to the penetration and loss of C8-C14 organic matter, and due to the high gas resistance of the chromatographic column and the limited flow rate that the chromatographic column and mass spectrometer can withstand, the thermal desorption flow rate is limited, resulting in incomplete thermal desorption of low-volatile organic matter. In order to expand the measurement of particulate low-carbon organic matter, the present application designs a small focusing module with a simple structure and easy operation for low-temperature and adsorbent dual enrichment after filter membrane sampling. The device can not only enrich the low-carbon organic matter that is easy to lose with an adsorbent, but also re-capture the high-carbon organic matter at low temperature, ensuring that it can subsequently enter the GCMS module without loss, reducing the tailing phenomenon of the material peak. The focusing module adopts a pneumatic control method, which can quickly switch the low-temperature enrichment and high-temperature analysis of organic matter, avoiding the temperature ambiguity phenomenon of high and low temperature temperature conversion, and can meet the temperature switching requirements from -40℃ low-temperature enrichment to 320℃ high-temperature desorption. The focusing module is small in size and compact in structure, which not only expands the monitoring range of the system, but the instantaneous desorption temperature rise can also avoid the peak tailing phenomenon of subsequent sample peaks.

[0121] The present application provides a method for using the above-mentioned enrichment and desorption device or the above-mentioned enrichment and desorption equipment for online measurement of organic matter in the volatility range of C8-C40 in the atmospheric particulate phase.

[0122] like Figure 4 As shown, the present application provides an online measurement method for organic matter in the volatile range of C8-C40 in the atmospheric particulate phase, including sampling mode, purge mode, focusing enrichment mode, injection mode, aging mode and cooling standby mode, providing data support for the source and precise tracing of atmospheric particulate matter.

[0123] The specific steps include:

[0124] Sampling steps: The computer interactive control system 32 controls the particulate matter enrichment and desorption device 22 (i.e., the enrichment and desorption device for organic matter in the volatility range of C8-C40 in the atmospheric particulate phase) to be in a collection state at 30°C. Through the suction action of the air pump 30, the atmospheric sample passes through the cutting head 19, the dissolver 20, the first electric three-way valve 21, the particulate matter enrichment and desorption device 22, the second electric three-way valve 23, and the first mass flow controller 29 in sequence and is discharged through the air pump 30, thereby intercepting the organic matter in the atmospheric particulate matter at the quartz fiber filter membrane 35 in the particulate matter enrichment and desorption device 22. During this stage, the adsorption focusing trap device 24 (i.e., the high- and low-temperature component) is in a low-temperature state of -20°C, awaiting enrichment. Another carrier gas, exiting the gas supply and gas line pressure control system 31, passes through the third electric three-way valve 25, the electric ball valve 26, the particle enrichment and desorption device 22, the mass flow controller 29, and the air pump 30 before being discharged, thereby protecting the electric ball valve 26 and the internal coating of the high-temperature pipeline therein at high temperature. Meanwhile, the protective carrier gas for the GCMS 28, exiting the gas supply and gas line pressure control system 31, passes through the electronic pressure controller 27 and enters the GCMS 28.

[0125] Purging step: Keep the particulate matter enrichment and desorption device 22 at a low temperature of 30°C. In this mode, after the carrier gas passes through the gas supply and pressure control system 31 and the first electric three-way valve 21, the carrier gas is purged on the quartz fiber filter membrane 35 and subsequent pipeline components in the particulate matter enrichment and desorption device 22 to remove excess interfering gases such as residual oxygen adsorbed in the quartz fiber filter membrane 35. During this stage, the adsorption focusing trap device 24 is still in a low-temperature enrichment state at -20°C (the carrier gas input to the micro-finger platform cylinder 11 is stopped, and the two low-temperature sub-temperature modules of the adsorption focusing trap device 24 are closed, so that the adsorption tube body 6 is in a low-temperature state of -20°C). The other carrier gas is discharged from the gas supply and gas line pressure control system 31 and passes through the third electric three-way valve 25, the electric ball valve 26, the particulate matter enrichment and desorption device 22, the mass flow controller 29, and the air pump 30, thereby protecting the electric ball valve 26 and the internal coating of the high-temperature pipeline at high temperature. At this time, the protective carrier gas of the GCMS 28 is discharged from the gas supply and gas line pressure control system 31 and enters the GCMS 28 through the electronic pressure controller 27.

[0126] Focusing and enrichment steps: In the focusing mode, the computer interactive control system 32 controls the heating wire in the particle enrichment and desorption device 22 to heat up immediately, which can heat the quartz fiber filter membrane 35 from 30°C to 320°C within 4 seconds; keep the focusing well 6 in the adsorption focusing well device 24 in a low-temperature enrichment state of -20°C (i.e., stop inputting carrier gas to the micro-finger platform cylinder 11, and close the two low-temperature sub-temperature modules of the adsorption focusing well device 24, so that the focusing well 6 is in a low-temperature state of -20°C). In this mode, one carrier gas, after passing through the gas supply and pressure control system 31 and the first electric three-way valve 21, is used to purge the substances thermally desorbed from the quartz fiber filter membrane in the particulate matter enrichment and desorption device 22 upward. The other carrier gas, after passing through the gas supply and pressure control system 31 and the second electric three-way valve 23, is used to purge the substances thermally desorbed from the quartz fiber filter membrane in the particulate matter enrichment and desorption device 22 downward. The purge substances are then carried from the upper and lower channels through the BA port of the three-way ball valve 26 to the adsorbent in the focusing trap 6 at a temperature of -20°C in the adsorption focusing trap device 24. The vaporized and desorbed high-carbon substances are captured by the empty pipe portion at the front end at -20°C, while the easily volatile low-carbon organic matter is captured by the low-temperature adsorbent. Excess unadsorbed impurities are discharged into the ambient atmosphere through the third electric three-way valve 25. At this time, the protective carrier gas for the GCMS 28 is discharged from the gas supply and gas line pressure control system 31 and then flows through the electronic pressure controller 27 to the GCMS 28.

[0127] Measurement steps: After the adsorption and focusing enrichment of the organic matter is completed, the computer interactive control system 32 controls the adsorption tube body 6 in the adsorption and focusing trap device 24 to rapidly heat up from a low temperature of -20°C to a high temperature of 320°C for desorption (i.e., the carrier gas from the gas supply and pressure control system 31 drives the micro-finger platform cylinder 11 to open, driving the two low-temperature modules to expand, and the computer interactive control system 32 controls the heating wire wrapped around the adsorption tube body 6 to rapidly operate). After the carrier gas passes through the gas supply and pressure control system 31 and the third electric three-way valve 25, the organic matter to be measured, which is released from the high temperature of the adsorption tube body 6 enriched in the adsorption and focusing trap device 24, is brought into the GCMS 28 through the AC port of the electric three-way ball valve 26 for analysis and measurement. At this time, the electronic pressure controller 27 is closed, and no gas output is provided.

[0128] Aging step: After the injection is completed, in order to remove residual impurities in the system pipeline, the computer interactive control system 32 controls the electric three-way ball valve AB position to be connected, and after coming out of the gas supply and gas line pressure control system 31, it passes through the electronic pressure controller 27 to the GCMS 28, providing the GCMS 28 with the corresponding separation and measurement carrier gas; at the same time, the particulate matter enrichment and desorption device 22 (i.e., the enrichment and desorption device) and the adsorption focusing trap device 24 (i.e., the high and low temperature component) are controlled to be in a high temperature state of 330°C. After the carrier gas comes out of the gas supply and gas line pressure control system 31, it passes through the first electric three-way valve 21, the particulate matter enrichment and desorption device 22, the second electric three-way valve 23, the mass flow controller 29, and the air pump 30, and then performs high-temperature carrier gas cleaning on the pipes and parts in the particulate matter enrichment and desorption device 22; another carrier gas comes out of the gas supply and gas line pressure control system 31, passes through the third electric three-way valve 25, the electric ball valve 26, the particulate matter enrichment and desorption device 22, the mass flow controller 29, and the air pump 30, thereby achieving aging cleaning of the pipes and parts in the adsorption focusing trap device 24;

[0129] Cooling and standby step: After the aging and cleaning is completed, the computer interactive control system 34 controls the particle enrichment and desorption device 22 and the high and low temperature components 24 to be in a low temperature state for enrichment, waiting for the next particle collection process. A carrier gas is discharged from the gas supply and gas line pressure control system 31 through the third electric three-way valve 25, the electric ball valve 26, the particle enrichment and desorption device 22, the mass flow controller 29, and the air pump 30, thereby protecting the electric ball valve 26 at high temperature and the internal coating of the high-temperature pipeline therein; at this time, the GCMS 28 is still in the programmed temperature rise and mass spectrometry detection stage, and its separation and detection carrier gas is provided by the gas supply and gas line pressure control system 31 through the electronic pressure controller 27;

[0130] Thus, a complete cycle of online measurement of atmospheric particulate organic matter is completed. The computer interactive control system 32 realizes time sequence control of the entire system and components, and the six steps can be automatically cycled.

[0131] To minimize the loss of sticky organic particles within the system, all components and continuous transmission pipelines after thermal desorption are equipped with 300-320°C adjustable high-temperature heating devices throughout the process, and the connection length of the internal pipelines is shortened as much as possible to minimize the loss of high-carbon organic matter, especially C35-C40 and PAH substances with more than 4 rings, in the pipelines.

[0132] The entire device system has a simple gas path and is easy to operate. It can directly monitor low-concentration particulate organic matter in the volatility range of C8-C40 under atmospheric conditions online. The time resolution is 30-90 minutes, and the sampling time can be freely adjusted according to measurement needs.

[0133] Example 1

[0134] like Figure 1 As shown, in the enrichment and desorption device, the tube body 33 has a diameter of 1 / 2 inch and a length of 6 cm. Made of quartz glass, the quartz glass tube 33 has a thin wall of 1 mm. A quartz support structure 37 is welded 2 cm upstream of the sample inlet of the quartz glass tube 33. A patch-type heating membrane 36, corresponding to the size of the 1 / 2-inch quartz glass tube 33, is placed above the quartz support structure 37. A heating wire with a certain resistance value is deployed within the heating membrane 36. The heating voltage is 24V and the heating power is 80W. A high-purity quartz filter membrane 35 is selected as the actual particle sampling component. The quartz fiber filter membrane 35 is 1 / 2 inch in size and is placed closely to the patch-type heating membrane 36. The larger filter membrane provides sufficient surface area for particle sampling. A 3 / 8-inch thin-walled quartz liner 34 is placed between the quartz fiber filter membrane 35 and the sampling port of the quartz glass tube 33 to protect the filter membrane from movement caused by airflow. Placing the patch temperature sensor 39 between the quartz fiber filter 35 and the patch heating diaphragm 36 and close to the side of the quartz transmission tube 40 can accurately monitor the actual temperature at the sampling filter. The circuit connection lines of the patch heating diaphragm 36 and the patch temperature sensor 39 are wrapped with a layer of high-temperature resistant quartz glass fiber protective cover. A quartz transmission tube 40 with a diameter of 3mm is welded under the quartz support structure 37 and is led out from a hole 4cm below the quartz glass tube body 33. The lead-out length is 2cm. The 3mm diameter quartz transmission tube 40 can be used to place the circuit connection lines of the patch heating diaphragm 36 and the patch temperature sensor 39. The tail end of the quartz transmission tube 40 is sealed with sealant 42 to prevent air leakage. In actual application, when the quartz fiber filter 35 is at a high temperature thermal desorption temperature of 320℃, the temperature of the sealant 42 is actually only 40℃. A 1 / 16-inch hole is drilled just below the lower end of the quartz support structure 37, and a 1 / 16-inch desorption quartz tube 38 is welded to it. This desorption quartz tube 38 is used to transfer the thermally desorbed material to the subsequent passivation three-way ball valve. A commercial, high-temperature-resistant polyimide O-ring 41 is used to seal the air path between the two. Furthermore, to ensure a seal between the upper and lower ends of the quartz glass tube 33 and the stainless steel, commercial O-rings are also used to seal the subsequent electric three-way valve.

[0135] Example 2

[0136] like Figure 4As shown, an enrichment and desorption device includes the enrichment and desorption device in Example 1, and also includes a high and low temperature component, including a high temperature module, a low temperature module and a high and low temperature switching module, the high temperature module includes an adsorption tube body 6 and an insulating resistance wire tightly wound around the outer wall of the body, the adsorption tube is filled with Tenax adsorbent, the adsorption tube body is a thin-walled corrosion-resistant 316 stainless steel that has been passivated, and the dimensions of the adsorption tube body are as follows: inner diameter: 2.2mm, outer diameter: 2.5mm, length: 600mm. A layer of insulating sleeve 53 is also included between the adsorption tube and the resistance wire, and the insulating sleeve 53 is wrapped around the outer periphery of the adsorption tube body 6. The material of the insulating sleeve is glass fiber cotton. The outer wall of the adsorption tube body is tightly wound with an insulating resistance wire, which serves as a heating unit for providing high temperature for analysis. A protective sleeve 15 made of glass fiber is wrapped around the outer layer of the resistance wire. The protective sleeve 15 serves as a protection unit for protecting the resistance wire. In order to monitor the temperature at the adsorption tube in real time, a temperature sensor 42 is placed between the adsorption tube 6 and the insulating sleeve 53. The temperature sensor 42 is close to the outer wall of the adsorption tube and can more realistically display the real-time temperature of the adsorbent. In order to reduce the insufficient enrichment and analysis of organic matter caused by temperature discrimination, an external PID control system is used to control the temperature of the adsorbent at +0.1 degrees, ensuring the temperature accuracy of the adsorbent itself. The high-temperature module with a resistance wire tightly wound around the outer wall of the adsorption tube can raise the temperature of the adsorption tube to 320℃-350℃. The low-temperature module includes a cooling plate, a metal block, plastic screws, a temperature sensor and a heat dissipation unit. The metal block is composed of two symmetrical sub-copper blocks with a semicircular groove in the center and can be opened and closed. The adsorption tube can be fitted in the groove formed by the two sub-copper blocks. The cooling plate is a three-stage semiconductor refrigeration element that can reduce the temperature of the adsorption tube to -40℃ and can continuously provide low temperature. The dimensions of the two sub-copper blocks are both 130mm*30mm. An aluminum protective shell is added to the outside of the copper block. The aluminum protective shell measures 140*33mm. The aluminum protective shell and the two half copper blocks are connected using M4*12 PTFE screws. The gap between them is filled with thermal insulation cotton to reduce the temperature transmission loss of the sub-temperature module and air. A support rod is used to secure and connect the adsorption tube. The lower end of the support rod is connected to the workbench via an insulating pad to reduce temperature transmission losses. The upper end of the support rod is connected to the adsorption tube via an M4*16 stainless steel screw, thus supporting and securing the adsorption tube. The low-temperature module's temperature sensor is placed in the side opening of the copper block. Specifically, an opening is made between the copper block and the side of the aluminum protective shell, the size of which is compatible with the outer diameter (4mm) of the low-temperature sensor. The low-temperature sensor is placed inside the copper block. The high-low temperature switching module includes a pneumatic device, which includes a micro-finger platform cylinder, a two-position five-way valve, a PU pneumatic high-pressure pipe, and a high-pressure air source. The micro-finger platform cylinder is connected to the bottom of the two sub-metal blocks via stainless steel connecting columns. The air inlet and outlet of the micro-finger platform cylinder are respectively connected to the working port of a two-position five-way valve. The air inlet of the two-position five-way valve is connected to the high-pressure air source, and the two exhaust ports of the two-position five-way valve are connected to the muffler.

[0137] Figure 5 This graph shows the chemical composition and signal value of atmospheric particulate matter collected using the online particulate matter enrichment monitoring system described in this application. The horizontal axis represents the acquisition time, and the vertical axis represents the TIC intensity signal value of the Agilent mass spectrometer. This system's measurements provide molecular-level information on atmospheric particulate matter, providing fundamental data support for tracing the source of atmospheric particulate matter and refined management and control.

Claims

1. A device for enriching and desorbing organic matter in the C8-C40 volatile range in atmospheric particulate phase, characterized in that: include: Tube body, desorption tube and transmission tube; The tube body has an inlet and an outlet on both sides thereof; In the direction of the injection of the organic matter, a "sandwich" integrated structure consisting of a quartz fiber filter membrane, a patch-type heating membrane and a quartz support net is nested inside the tube body; a desorption tube, one side of which is welded to the side surface of the tube body, and the other side of which extends radially outward along the tube body; The transmission tube is L-shaped, with one side of the transmission tube welded to the "sandwich" integrated structure, wherein one side of the L-shaped transmission tube extends along the inner wall of the tube body, and the other side of the L-shape protrudes from the other side of the tube body opposite to the side surface welded with the desorption tube; the wires connected to the heating diaphragm and the wires connected to the patch temperature sensor are located inside the transmission tube; In the direction of the injection of the organic matter, the "sandwich" integrated structure, the desorption tube and the transmission tube are arranged at different positions of the tube body; The heating diaphragm has a heating wire inside; the enrichment and desorption device also includes a patch temperature sensor, which is located between the filter membrane and the heating diaphragm and close to the side of the tube body where the transmission tube is located; in the injection direction of the organic matter, the "sandwich" integrated structure is arranged upstream of the desorption tube, and the transmission tube is arranged downstream of the desorption tube; The ratio of the distance between the "sandwich" integrated structure and the desorption tube to the total length of the tube body is (0.3-1):6; The ratio of the distance between the "sandwich" type integrated structure and the transmission pipe to the total length of the pipe body is (1-3):6; The ratio of the distance between the transmission tube and the injection port to the total length of the tube body is (3-4):6; The ratio of the distance between the desorption tube and the injection port to the total length of the tube body is (1.5-3.5):6; Alternatively, in the sampling direction of the organic matter, the desorption tube is arranged upstream of the "sandwich" type integrated structure, and the transmission tube is arranged downstream of the "sandwich" type integrated structure; The ratio of the distance between the "sandwich" integrated structure and the desorption tube to the total length of the tube body is (0.3-1):6; The ratio of the distance between the "sandwich" type integrated structure and the transmission pipe to the total length of the pipe body is (1-3):6; The ratio of the distance between the transmission tube and the injection port to the total length of the tube body is (3-4):6; The ratio of the distance between the desorption tube and the injection port to the total length of the tube body is (0.5-2.5):

6.

2. The enrichment and desorption device according to claim 1, characterized in that: The enrichment and desorption device further comprises an inner liner, which is arranged inside the tube body and between the sample inlet and the filter membrane.

3. The enrichment and desorption device according to claim 1, characterized in that: The first O-ring or PTFE joint is used to seal both sides of the tube; The desorption tube is sealed with a second O-ring; The transmission pipe is sealed with sealant.

4. The enrichment and desorption device according to claim 3, characterized in that: The material of the first O-ring is fluororubber or nitrile rubber; The material of the second O-ring is polyimide; The sealant is made of inorganic ceramic material.

5. The enrichment and desorption device according to claim 1, characterized in that: The enrichment and desorption device further comprises a refrigeration unit arranged outside the tube body.

6. The enrichment and desorption device according to claim 5, characterized in that: The refrigeration unit is a fan.

7. A device for enriching and desorbing organic matter in the C8-C40 volatility range in atmospheric particulate phase, characterized in that: The invention comprises the enrichment and desorption device according to any one of claims 1 to 6.

8. The enrichment and desorption equipment according to claim 7, further comprising a high and low temperature component; The high and low temperature components include a high temperature module, a low temperature module and a high and low temperature switching module.

9. The enrichment and desorption device according to claim 8, wherein: The high-temperature module includes an adsorption tube and a resistance wire wound around the outside of the adsorption tube. The adsorption tube is filled with Tenax series adsorbent.

10. The enrichment and desorption equipment according to claim 9, wherein: An insulating sleeve is further provided between the adsorption tube and the resistance wire, and the insulating sleeve is wrapped around the outer periphery of the adsorption tube.

11. The enrichment and desorption equipment according to claim 9, wherein: The high temperature module further includes a protection unit, which is wrapped around the outer periphery of the resistance wire.

12. The enrichment and desorption device according to claim 11, wherein: The high-temperature module further includes a temperature sensor, which is arranged outside the adsorption tube body and located between the insulating sleeve and the adsorption tube.

13. The enrichment and desorption equipment according to claim 9, wherein: The low-temperature module includes a refrigeration plate and a metal block. The metal block is composed of two symmetrical sub-metal blocks with a semicircular groove at the center and can be opened and closed. The adsorption tube can be fitted in the groove formed by the two symmetrical sub-metal blocks.

14. The enrichment and desorption device according to claim 13, wherein: The cold end of the refrigeration plate is in close contact with the metal block.

15. The enrichment and desorption equipment according to claim 9, wherein: The high and low temperature switching module includes a pneumatic drive device, which realizes the switching of the adsorption tube between the high temperature mode and the low temperature mode by separating and closing the low temperature sub-metal block.

16. The enrichment and desorption device according to claim 15, wherein: When the carrier gas is introduced into the pneumatic drive device, the two symmetrical sub-metal blocks move relative to each other, so that there is a gap between the two symmetrical sub-metal blocks and the adsorption tube, and the heating module is controlled to operate in a high-temperature mode; When the pneumatic drive device does not pass the carrier gas, the two symmetrical sub-metal blocks move toward each other so that the two symmetrical sub-metal blocks are attached to the adsorption tube, and the heating module is controlled to stop working and enter the low-temperature mode.

17. A method for using the enrichment and desorption device according to any one of claims 1 to 6 or the enrichment and desorption equipment according to any one of claims 7 to 16 for online measurement of particulate organic matter in the C8-C40 volatility range in atmospheric particulate phase.

18. The method according to claim 17, characterized in that include Sampling step, purging step, focusing and enrichment step, and measurement step; wherein, Sampling step: passing the sample to be tested into the enrichment and desorption device so that the organic matter in the particle phase is enriched in the enrichment and desorption device; Purging step: purging the enrichment and desorption device and its transmission route or the enrichment and desorption equipment and its transmission route with carrier gas to remove excess gas; Focusing on the enrichment step: desorbing the organic matter in the particle phase adsorbed in the enrichment and desorption device and entering the enrichment and desorption equipment; Measurement steps: desorb the particle phase organic matter adsorbed on the enrichment and desorption equipment, and separate and measure the particle phase organic matter.

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