Method and device for capturing and determining active organic free radicals in atmosphere

Abstract

The invention discloses a method and a device for capturing and determining active organic free radicals in atmosphere. The device for capturing the solid organic free radicals in the atmosphere based on a capturing agent-fixing material comprises a lossless small column capturing unit of capturing agent-solid phase filler, a negative pressure air exhaust unit for stabilizing the flow and a constant temperature control unit for stabilizing the temperature, and each unit is connected and sealed with a customized polytetrafluoroethylene piece through a polytetrafluoroethylene pipe and a pipe connecting piece. The method for capturing the organic free radicals by using the device comprises the following steps: weighing a solid-phase filler, and uniformly filling a pipeline of the free radical capturing device with the solid-phase filler; the method comprises the following steps: activating a solid-phase filler by using an organic solvent, and balancing by using ultrapure water; preparing a free radical scavenger solution; enabling the free radical trapping agent solution to pass through the activated solid-phase filler in the free radical trapping device, so that free radicals in the free radical trapping agent solution are fully complexed with the solid-phase filler; and free radical capture is carried out, so that enrichment of trace environmental free radicals is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of air quality measurement, and relates to the precise measurement of active free radicals in the atmosphere, and specifically to a method and a device for realizing solid-state capture of active organic free radicals in the atmosphere and non-targeted analysis and determination thereof, which can be used to monitor the species, distribution and concentration of active organic free radicals in the atmosphere, so as to determine their relative reaction mechanisms and precisely eliminate measurement interferences, thereby reducing the detection limit. Background Art

[0002] At present, the focus of air pollution prevention and control has begun to shift from primary pollution to secondary pollution. In order to achieve continuous improvement of regional air quality, it is urgent to clarify the secondary fine particulate matter (PM 2.5 ) and ozone, and the nonlinear relationship in the regulation of secondary pollution. Since trace pollutant gases emitted by humans and nature are all reducing gases, atmospheric oxidizability is a key link in understanding the formation of secondary pollution. Among them, the source and transformation mechanism of atmospheric organic free radicals (R, RO, RO2, etc.) constitute the core connotation of atmospheric oxidizability in the troposphere. However, the concentration of atmospheric organic free radicals is low, the activity is high, and the reaction system is complex. Its accurate measurement and simulation are extremely difficult, which is a very challenging international academic frontier problem in atmospheric environmental chemistry research. At present, there are many technologies for detecting organic free radicals, mainly including electron spin resonance (ESR) and laser induced fluorescence (LIF). Electron spin resonance (ESR) technology converts short-lived free radicals into longer-lived spin adducts through spin traps, making them detectable. It has been widely used in food science, advanced oxidation processes, and drug development. However, in the determination of environmental free radicals, ESR technology faces many difficulties, such as harsh analysis conditions and complex spectral information. These problems limit its application in environmental sample analysis. Although the combination of spin trapping technology and mass spectrometry has become an important means of detecting and identifying unknown free radicals, it is mainly used for aqueous phase reactions under laboratory conditions and has not yet been widely used in the analysis of actual environmental samples, especially atmospheric samples. Laser induced fluorescence (LIF) technology is currently one of the most widely used methods in the determination of atmospheric organic free radicals. Its principle is to excite hydroxyl radicals through lasers of a specific wavelength, causing them to undergo a resonant transition and then emit fluorescence, and the fluorescence intensity is proportional to the concentration of hydroxyl radicals. LIF technology is widely used in the measurement of free radicals because of its simple principle and high sensitivity. However, LIF technology relies on large equipment and is suitable for large-scale detection occasions, and is not suitable for the measurement of free radicals with unclear optical characteristics. In addition, traditional free radical analysis methods are mostly targeted analysis, often ignoring a large number of mass spectrometry signals from unknown substances, and it is difficult to deal with the complex and diverse free radicals in the environment. Although scientists have developed some effective environmental free radical detection methods after years of research, the application scope of these technical means is still limited, and it is difficult to fully explain the increasingly complex environmental problems. Summary of the invention

[0003] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a solid-state capture device for atmospheric organic free radicals and a non-targeted analysis and identification method. The solid-state capture device designed by the present invention can realize the fixed capture of free radicals with short chemical lifetime and high activity to maintain their enrichment concentration and ensure the implementation of free radical measurement and analysis; the method provided by the present invention can realize the screening and identification of non-targeted free radicals and the targeted concentration measurement with extremely low detection limit.

[0004] The solid-state capture device designed by the present invention is a free radical solid-state capture device based on a capture agent-fixing material. The capture agent is fixed to a solid phase filler, and the filler is loaded into a capture column, so that the capture and non-targeted analysis of free radicals in gas or liquid can be realized. The solid-state capture device for atmospheric organic free radicals based on a capture agent-fixing material provided by the present invention includes three main units. The three main units are: a non-destructive "small column" capture unit including a capture agent-solid phase filler, a negative pressure exhaust unit with a stable flow rate, and a constant temperature control unit with a stable temperature. Among them, the non-destructive "small column" capture unit of the capture agent-solid phase filler is the core of the capture and measurement of atmospheric organic free radicals and the device designed by the present invention. The three units are debugged and optimized separately, and each unit is connected and sealed by a polytetrafluoroethylene (Teflon) tube, a Teflon pipe connector and a customized tetrafluoro piece. After integrated debugging, the overall air tightness of the system is good, and the flow and temperature control are stable.

[0005] The present invention proposes to achieve the enrichment of organic free radicals in the atmosphere based on the above-mentioned free radical solid-state capture device, which is used to achieve the screening and identification of non-targeted free radicals and the implementation of extremely low detection limit targeted concentration measurement. Among them, the free radical solid-state capture method based on the capture agent-fixing material designed by the present invention includes: dissolving the selected suitable free radical capture agent (commercial or independently chemically synthesized) in ultrapure water (HPLC), fixing the solid phase filler in a non-destructive "small column" capture unit, activating by quantitative capture agent titration and fixing the filler with nitrogen by blowing dry with high-purity nitrogen. In specific implementation, the non-destructive "small column" capture unit is composed of a 5cm long 1 / 2 outer diameter Teflon tube, a 3cm long 1 / 4 outer diameter Teflon tube, a 1 / 2 to 1 / 4 Teflon pipe connector, 200 mg solid phase filler, and a 9.52mm outer diameter gasket (polyethylene gasket). The solid phase filler is loaded into a Teflon tube with an outer diameter of 1 / 2 of the non-destructive "small column" capture unit, and a polyethylene gasket with an outer diameter of 9.52 mm is connected to the bottom and connected to a Teflon tube with an outer diameter of 1 / 4 with a Teflon pipe connector and pressed and sealed. The use of comprehensive Teflon further reduces the loss of atmospheric organic free radicals during the collection process and reduces airflow disturbances. Gaskets of appropriate size are conducive to the enrichment sampling of atmospheric organic free radicals by solid phase fillers, so as to accurately determine the collection time and reduce interference with subsequent non-targeted identification or targeted quantification. In addition, the non-destructive "small column" capture unit can be directly used to capture free radicals in liquids.

[0006] Due to the extremely low concentration of atmospheric organic free radicals and their strong reactivity, the selection of the capture agent, the flow rate of the sampling gas, and the design of the inner diameter in the free radical solid capture device based on the capture agent-fixed material are the key and core technologies for the device to collect and enrich atmospheric organic free radicals. In the selection of the capture agent, it is necessary to ensure both its rapid reactivity with specific key atmospheric organic free radicals and the chemical stability of its products, and to meet the conditions of broad-spectrum capture, that is, to achieve the enrichment of as many organic free radicals in the atmosphere as possible. In the selection of the flow rate of the sampling gas, it is necessary to meet the conditions that its residence time in the sampling "small column" is long enough to react with the capture agent and the residence time is short enough to reduce the wall loss of the free radicals. The flow rate of the sampling gas needs to meet the requirement of laminar flow for the Reynolds number in the sampling "small column", and it should not be too slow to cause the complete loss of free radicals. The structure and inner diameter design of the capture device directly affect the efficiency of the reaction between free radicals and the capture agent in the sampling "small column", thereby affecting the sensitivity and stability of free radical measurement.

[0007] The invention provides a free radical capture device, which comprises a capture column, a solid phase filler and a capture agent.

[0008] The preferred material of the free radical capture device is polytetrafluoroethylene pipes and pipe connectors. The preferred solid phase filler is HLB filler. The capture agent is any free radical capture agent.

[0009] The present invention also provides a method for capturing free radicals using the free radical capture device, the steps of which include:

[0010] 1) Tightly connect the polyethylene gasket to the pipeline and pipe fittings to prevent the solid filler from escaping from the outlet of the device;

[0011] Weigh an appropriate amount of solid phase filler and fill it evenly into the pipeline of the free radical capture device.

[0012] 2) Further, the solid phase filler is activated with an organic solvent, and the activated filler is balanced with ultrapure water.

[0013] Preferably, the organic solvent for activating the filler can be methanol in an amount of 5 times the volume of the filler.

[0014] 3) Accurately weigh an appropriate amount of a free radical scavenging agent with a purity greater than 99.9%, and dissolve it in a 10% methanol aqueous solution to prepare a free radical scavenging agent solution.

[0015] 4) Further, the prepared free radical scavenger solution is slowly passed through the activated solid phase filler in the free radical scavenger device, so that the free radical scavenger in the free radical scavenger solution is fully complexed with the solid phase filler. The free radicals are captured by the free radical scavenger device, which can achieve the enrichment of trace environmental free radicals.

[0016] When capturing liquid, the free radical capture agent solution is completely and slowly passed through the activated solid phase filler in the free radical capture device, and then a proper amount of ultrapure water is added to the device, and the liquid to be tested can be slowly injected into the free radical capture device for free radical capture.

[0017] When capturing gas, the free radical capture agent solution is completely and slowly passed through the activated solid phase filler in the free radical capture device, and then an appropriate amount of ultrapure water is added to the device. After the liquid in the free radical capture device is blown dry with high-purity nitrogen, the gas to be tested can be passed into the free radical capture device for free radical capture. The gas flow rate can be adjusted by connecting a vacuum pump at the end of the free radical capture device.

[0018] Preferably, the flow rate of gas through the free radical capture device can be maintained at 500 mL / min to ensure that the gas has sufficient time to combine with the capture agent, ensure that the gas can pass through the free radical capture device, and ensure that the free radicals will not be annihilated before complexing with the filler.

[0019] Furthermore, when capturing free radicals, the free radical capturing device may be heated to increase the complexation rate between the free radicals and the capturing agent.

[0020] Preferably, during the capturing process, the temperature of the free radical capturing device can be maintained at about 40°C.

[0021] The process of the method of the present invention for non-targeted analysis using captured free radicals is as follows: the captured free radical capture device is eluted with an appropriate amount of organic solvent, the capture agent and the free radical capture product are eluted from the solid phase filler, and then non-targeted analysis is performed by high performance liquid chromatography tandem with high resolution mass spectrometry.

[0022] Preferably, methanol can be selected as the organic solvent for eluting the product.

[0023] Preferably, the chromatographic column of the high performance liquid chromatography can use a C18 column to perform liquid phase separation on the free radical capture product, thereby improving the sensitivity of the free radical analysis.

[0024] Preferably, the mobile phase of the high performance liquid chromatography can be pure water and acetonitrile.

[0025] Preferably, the high-resolution mass spectrometry analysis method can use a primary high-resolution mass spectrometry scan combined with an automatically triggered secondary scanning mode to perform non-targeted high-resolution analysis.

[0026] The present invention provides a method for identifying free radicals captured by non-targeted methods, which extracts mass spectrometry data from non-targeted analysis data of high-performance liquid chromatography-tandem high-resolution mass spectrometry of captured samples (captured organic free radicals) and process blank control samples, and performs differential molecule screening. The differential molecules are free radicals to be determined, which means that the identification of free radicals captured by non-targeted methods is achieved.

[0027] Furthermore, the mass spectrometry data extraction method can be performed using Waters' Progenesis QI software to extract the mass spectrometry m / z information and mass spectrometry signal intensity information at all peak times.

[0028] Furthermore, by T test, differential molecules with p<0.05 were selected for differential molecule screening.

[0029] Furthermore, the screened differential molecules are subjected to mass spectrometry data analysis, and their elemental composition can be calculated by the mass number of the high-resolution mass spectrometry, and the elemental composition of the free radicals can be output.

[0030] Furthermore, in order to identify the structure of free radicals, the captured capture agent and free radical combination product can be chemically synthesized, and the synthetic standard can be matched with the free radicals identified by differential molecular screening through chromatographic and mass spectrometric secondary information, ultimately obtaining the specific structural information of the unknown free radical.

[0031] Compared with the prior art, the beneficial technical effects of the present invention are:

[0032] The present invention provides a method and device for realizing solid-state capture of active organic free radicals in the atmosphere and non-targeted analysis and determination thereof. The method and device are based on a self-invented solid-state capture device and a non-targeted high-resolution mass spectrometry measurement and identification technology of organic free radicals. The method can be used to monitor the species, distribution and concentration of active organic free radicals in the atmosphere, realize non-targeted analysis and identification of free radicals, determine their relative reaction mechanisms, accurately eliminate measurement interferences, and reduce detection limits.

[0033] The present invention can improve the accuracy of measuring the concentration of atmospheric organic free radicals, and is an important link in completing the species identification and concentration distribution quality control of atmospheric organic free radicals. It can effectively deduct the measurement interference of the reaction system on the free radicals and realize the precise exploration of the chemical mechanism of atmospheric organic free radicals.

[0034] (i) The present invention uses a solid-phase filler and a correspondingly developed commercial or independently chemically synthesized capture agent to perform solid-state capture of atmospheric organic free radicals, a key step, to achieve time-linear enrichment of active organic free radicals. The stability of the measurement results can be tested by capturing organic free radicals in a laboratory environment / commercial fixed concentrations, and the accuracy of the measurement results can be determined. At the same time, the collection conditions can be adjusted in time according to the experimental conditions, so that the concentration of atmospheric organic free radicals meets the measurement requirements and remains stable.

[0035] (ii) The present invention uses Teflon material to make a free radical solid-state capture device, calculates the Reynolds number to ensure a laminar flow state, effectively avoids gas circulation in the "small column" and reduces wall loss;

[0036] (III) The present invention can realize high-throughput non-targeted screening of free radicals and can perform structural analysis on the free radicals screened in non-targeted screening;

[0037] (iv) The present invention can accurately quantify the target free radicals detected by non-targeted screening, has high sensitivity for free radical detection, and can realize the detection and analysis of trace free radicals;

[0038] (V) The device provided by the present invention is small in size, easy to operate, install and disassemble, and has high time resolution, high sensitivity, high stability, low cost, and simple operation and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The flowchart of the method of the present invention is shown in FIG.

[0040] Figure 2 Structural diagram of the free radical capture device designed for the present invention.

[0041] Figure 3 It is the identification chromatogram of some alkyl free radicals in the examples of the present invention.

[0042] Figure 4This is a high collision energy mass spectrum for the identification of some hydrocarbon free radicals in the examples of the present invention.

[0043] Figure 5 The mass spectra with low collision energy are used to identify some hydrocarbon free radicals in the examples of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention is clearly and completely described below in conjunction with the accompanying drawings.

[0045] The present invention provides a free radical capture device, such as Figure 2 As shown, it includes a capture column, a solid phase filler and a capture agent.

[0046] The preferred material of the free radical capture device is polytetrafluoroethylene pipes and pipe connectors. The preferred solid phase filler is HLB filler. The capture agent is any free radical capture agent.

[0047] The present invention also provides a method for capturing free radicals using the free radical capture device, such as Figure 1 As shown, the steps include:

[0048] 1) Tightly connect the polyethylene gasket to the pipeline and pipe fittings to prevent the solid filler from escaping from the outlet of the device;

[0049] Weigh an appropriate amount of solid phase filler and fill it evenly into the pipeline of the free radical capture device.

[0050] 2) Further, the solid phase filler is activated with an organic solvent, and the activated filler is balanced with ultrapure water.

[0051] Preferably, the organic solvent for activating the filler can be methanol in an amount of 5 times the volume of the filler.

[0052] 3) Accurately weigh an appropriate amount of a free radical scavenging agent with a purity greater than 99.9%, and dissolve it in a 10% methanol aqueous solution to prepare a free radical scavenging agent solution.

[0053] 4) Further, the prepared free radical scavenger solution is slowly passed through the activated solid phase filler in the free radical scavenger device, so that the free radical scavenger in the free radical scavenger solution is fully complexed with the solid phase filler. The free radicals are captured by the free radical scavenger device, which can achieve the enrichment of trace environmental free radicals.

[0054] When capturing liquid, the free radical capture agent solution is completely and slowly passed through the activated solid phase filler in the free radical capture device, and then a proper amount of ultrapure water is added to the device, and the liquid to be tested can be slowly injected into the free radical capture device for free radical capture.

[0055] When capturing gas, the free radical capture agent solution is completely and slowly passed through the activated solid phase filler in the free radical capture device, and then an appropriate amount of ultrapure water is added to the device. After the liquid in the free radical capture device is blown dry with high-purity nitrogen, the gas to be tested can be passed into the free radical capture device for free radical capture. The gas flow rate can be adjusted by connecting a vacuum pump at the end of the free radical capture device.

[0056] Preferably, the flow rate of gas through the free radical capture device can be maintained at 500 mL / min to ensure that the gas has sufficient time to combine with the capture agent, ensure that the gas can pass through the free radical capture device, and ensure that the free radicals will not be annihilated before complexing with the filler.

[0057] Furthermore, when capturing free radicals, the free radical capturing device may be heated to increase the complexation rate between the free radicals and the capturing agent.

[0058] Preferably, during the capturing process, the temperature of the free radical capturing device can be maintained at about 40°C.

[0059] The process of the method of the present invention for non-targeted analysis using captured free radicals is as follows: the captured free radical capture device is eluted with an appropriate amount of organic solvent, the capture agent and the free radical capture product are eluted from the solid phase filler, and then non-targeted analysis is performed by high performance liquid chromatography tandem with high resolution mass spectrometry.

[0060] Preferably, methanol can be selected as the organic solvent for eluting the product.

[0061] Preferably, the chromatographic column of the high performance liquid chromatography can use a C18 column to perform liquid phase separation on the free radical capture product, thereby improving the sensitivity of the free radical analysis.

[0062] Preferably, the mobile phase of the high performance liquid chromatography can be pure water and acetonitrile.

[0063] Preferably, the high-resolution mass spectrometry analysis method can use a primary high-resolution mass spectrometry scan combined with an automatically triggered secondary scanning mode to perform non-targeted high-resolution analysis.

[0064] The present invention provides a method for identifying free radicals captured by non-targeted methods, which extracts mass spectrometry data from non-targeted analysis data of high-performance liquid chromatography-tandem high-resolution mass spectrometry of captured samples (captured organic free radicals) and process blank control samples, and performs differential molecule screening. The differential molecules are free radicals to be determined, which means that the identification of free radicals captured by non-targeted methods is achieved.

[0065] Furthermore, the mass spectrometry data extraction method can be performed using Waters' Progenesis QI software to extract the mass spectrometry m / z information and mass spectrometry signal intensity information at all peak times.

[0066] Furthermore, by T test, differential molecules with p<0.05 were selected for differential molecule screening.

[0067] Furthermore, the screened differential molecules are subjected to mass spectrometry data analysis, and their elemental composition can be calculated by the mass number of the high-resolution mass spectrometry, and the elemental composition of the free radicals can be output.

[0068] Furthermore, in order to identify the structure of free radicals, the captured capture agent and free radical combination product can be chemically synthesized, and the synthetic standard can be matched with the free radicals identified by differential molecular screening through chromatographic and mass spectrometric secondary information, ultimately obtaining the specific structural information of the unknown free radical.

[0069] The following examples describe the process of capturing free radicals in gas and non-targeted analysis and identification:

[0070] 1) Taking PBN free radical scavenger as an example, atmospheric free radical capture and non-targeted identification analysis were performed. First, PBN with a purity of >99.9% was dissolved in ultrapure water, and a gas capture group and a control group were set up for atmospheric capture.

[0071] 2) Prepare the free radical capture column. First, weigh an appropriate amount of HLB filler, fill the HLB filler into the developed column, activate it with an appropriate amount of methanol, and then balance it with water. Slowly add DMPO or PBN solution to the activated free radical capture column, and let it flow out naturally under the action of gravity, so that the capture agent and HLB filler are fully combined. After the capture agent completely passes through the free radical capture column, use high-purity nitrogen to blow dry the HLB filler.

[0072] 3) The air is sampled at a flow rate of 500 mL / min for free radical capture for a period of 1 to 6 hours.

[0073] 4) Carefully add an appropriate amount of methanol to the capture device after capture, and collect the effluent. The collected effluent is the free radical capture product.

[0074] 5) Using ACQUITY BEH C18 column (1.7μm, 2.1mm×100mm). The mobile phases of the chromatographic column were water (A) and methanol (B), the injection volume was 5μL, the column temperature was 40℃, and the flow rate was 0.3mL / min. The gradient elution method of the BEH C18 column was: 0-1.0min, 10% B; 1.0-2.0min, 10%-20% B; 2.0-3.0min, 20% B; 3.0-10.5min, 20%-68% B; 10.5-14.0min, 68%-100% B; 14.0-17.0min, 100% B; 17.0-17.1min, 100%-10% B; 17.1-20.0min, 10% B. The mass spectrometers all used ESI ionization source, selected positive ion mode, data acquisition mode was Scan mode, the scanning range was m / z 50 to 1000, and the desolvation gas was nitrogen. The capillary voltage was 3.0 kV, the cone voltage was 30 V, the extraction cone voltage was 4.0 V, the ion source temperature was 150 ° C, the desolvation gas temperature was 350 ° C, the cone gas (Cone Gas Flow) flow rate was 50 L / h, the desolvation gas flow rate was 600 L / h, and the collision energy was 5-40 V. Figure 3 Shown is the identification chromatogram of some alkyl free radicals in the examples of the present invention. Figure 4 Shown is a high collision energy mass spectrum for the identification of some hydrocarbon free radicals in the examples of the present invention. Figure 5 Shown is the low collision energy mass spectrum for the identification of some hydrocarbon free radicals in the examples of the present invention.

[0075] 6) The collected data were extracted and analyzed by Progenesis QI software for mass spectrometry data extraction, peak extraction, peak matching, peak alignment, and peak integration. The mass spectrometry data were screened based on the extracted mass spectrometry information, and the differential molecules were screened using the T test, and the differential molecules with p < 0.05 were selected. The experimental background and blanks were also excluded.

[0076] 7) In order to explore the mass spectrometry fragment information of PBN-free radicals and assist in free radical identification, PBN-OH was first analyzed. The ionization mode of PBN-OH adducts is [M] +. Further analysis of the mass spectrometry fragments of the hydroxyl spin adduct revealed that the cleavage mode of PBN-OH was the loss of tert-butyl (-C4H8). Based on this, we set C4H8 (56.0615) as neutral loss with a matching tolerance of 4mDa. On this basis, the data were quickly screened to obtain a list of possible free radical signals. The data set screened out by neutral loss was compared one by one with the data set obtained by the blank control group, the repeated signals in the blank group were removed, and the elemental composition analysis of the screened results was performed. When analyzing the elemental composition, the parameters were set to 11-50 carbon atoms, 15-100 hydrogen atoms, 1-50 nitrogen atoms and 1-50 oxygen atoms, and the degree of unsaturation was set to 4-50, further narrowing the identification range. The relative molecular mass deviation allowed for elemental composition analysis was 4mDa. To further improve the credibility of the results, the molecular formulas of the free radical adducts obtained by screening can be searched online in the Massbank database. Massbank is an open source network mass spectrometry database that contains mass spectrometry information of common metabolites and small molecular organic matter in the environment.

[0077] 8) Utilize UPLC-Q-TOF-MS-MS E Mode analysis of atmospheric samples, a total of 4665 mass spectral peak signals were detected in the positive ion mode, and C4H8 was used as the neutral loss data screen. There were 264 mass spectral signals with specific neutral loss. After blank comparison and elemental composition analysis, a total of 25 free radicals were finally screened out from the atmosphere, and the mass deviations were all less than 4mDa. The screening results of free radicals are shown in the table below.

[0078]

[0079] To sum up, the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A free radical capture device, characterized in that: The free radical capture device is a solid-state capture device for atmospheric organic free radicals based on a capture agent-fixed material, comprising: a non-destructive small column capture unit of a capture agent-solid phase filler, a negative pressure exhaust unit for stabilizing the flow rate, and a constant temperature control unit for stabilizing the temperature; each unit is connected and sealed by a polytetrafluoroethylene tube, a polytetrafluoroethylene pipe connector and a customized polytetrafluoroethylene part; The non-destructive small column capture unit includes: a polytetrafluoroethylene tube with an outer diameter of 1 / 2; a polytetrafluoroethylene tube with an outer diameter of 1 / 4; a 1 / 2 to 1 / 4 polytetrafluoroethylene pipe connector; a solid phase filler; a polyethylene gasket; The solid phase filler is loaded into a Teflon tube with a 1 / 2 outer diameter of the non-destructive small column capture unit, a polyethylene gasket is connected below, and the tube is connected to a Teflon tube with a 1 / 4 outer diameter using a Teflon tube connector and compressed and sealed.

2. The free radical capture device according to claim 1, characterized in that The 1 / 2 outer diameter polytetrafluoroethylene tube is 5 cm long; the 1 / 4 outer diameter polytetrafluoroethylene tube is 3 cm long; the outer diameter of the polyethylene gasket is 9.52 mm.

3. A method for capturing organic free radicals, characterized in that: Capturing organic free radicals using the free radical capture device according to claim 1 comprises the following steps: 1) Weigh the solid phase filler and evenly fill it into the pipeline of the free radical capture device; 2) activating the solid phase filler with an organic solvent, and balancing the activated solid phase filler with ultrapure water; 3) preparing a free radical scavenger solution; 4) slowly passing the prepared free radical scavenger solution through the activated solid phase filler in the free radical scavenging device, so that the free radicals in the free radical scavenger solution are fully complexed with the solid phase filler; 5) Using the free radical capture device obtained in step 4) to capture free radicals, so as to achieve the enrichment of trace environmental free radicals; comprising: When the object to be free radical captured is a liquid, the free radical capture agent solution is completely and slowly passed through the activated solid phase filler in the free radical capture device, and then ultrapure water is added to the free radical capture device, and the liquid to be free radical captured can be slowly injected into the free radical capture device for free radical capture; When the object to be free radical captured is a gas, the free radical capture agent solution is completely and slowly passed through the activated solid phase filler in the free radical capture device, and then an appropriate amount of ultrapure water is added to the device. After the liquid in the free radical capture device is blown dry with high-purity nitrogen, the gas to be free radical captured can be passed into the free radical capture device for free radical capture; a vacuum pump is connected to the end of the free radical capture device to adjust the gas flow rate.

4. The method for capturing organic free radicals according to claim 3, wherein: Step 3) specifically comprises: accurately weighing an appropriate amount of a free radical scavenging agent with a purity greater than 99.9%, and dissolving it in a 10% methanol aqueous solution, thereby preparing a free radical scavenging agent solution; The flow rate of the gas through the free radical capture device is maintained at 500 mL / min, so that the gas and the capture agent are fully combined, the gas can pass through the free radical capture device, and the free radicals will not be annihilated before complexing with the filler.

5. The method for capturing organic free radicals according to claim 4, characterized in that: When capturing free radicals, the free radical capturing device is heated to increase the complexation rate of the free radicals and the capturing agent; the temperature of the free radical capturing device is maintained at about 40°C.

6. A method for non-targeted analysis of free radicals, characterized in that: The free radicals are captured by the organic free radical capture method according to claim 3, the captured free radical capture device is eluted with an organic solvent, the capture agent and the free radical capture product are eluted from the solid phase filler, and then non-targeted analysis is performed by high performance liquid chromatography tandem with high resolution mass spectrometry.

7. The method for non-targeted analysis of free radicals according to claim 6, characterized in that: Methanol is selected as the organic solvent for eluting the product; The chromatographic column of the high performance liquid chromatography specifically uses a C18 column to perform liquid phase separation on the free radical capture product; The mobile phase of the high performance liquid chromatography specifically uses pure water and acetonitrile as the mobile phase; The high-resolution mass spectrometry analysis method specifically uses a primary high-resolution mass spectrometry scan combined with an automatically triggered secondary scanning mode to perform non-targeted high-resolution analysis.

8. A method for identifying free radicals captured by non-targeted methods, characterized in that: The free radicals are captured by the organic free radical capture method described in claim 2, and the non-targeted analysis data of the captured samples and the process blank control samples by high performance liquid chromatography-tandem high resolution mass spectrometry are extracted for mass spectrometry data extraction and differential molecular screening.

9. The method for identifying free radicals captured by non-targeted methods as claimed in claim 8, characterized in that: The mass spectrometry data extraction method was specifically performed using Progenesis QI software to extract the mass spectrometry m / z information and mass spectrometry signal intensity information at all peak times; In the T test method, specifically, differential molecules with p<0.05 are selected for differential molecule screening; The screened differential molecules were subjected to mass spectrometry data analysis, and the elemental composition of the free radicals was obtained by calculating the mass number of the high-resolution mass spectrometry.

10. The method for identifying free radicals captured by non-targeted methods according to claim 8, characterized in that: The combination product of the capture agent and the free radical is chemically synthesized, and the synthetic standard is matched with the identified free radical by chromatography and mass spectrometry secondary information, so as to obtain the structural information of the free radical.

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