A laser analysis and proton transfer reaction mass spectrometry detection device and method for detecting non-volatile organic compounds

Abstract

The present invention relates to a laser analysis sampling proton transfer reaction mass spectrometry non-volatile organic detection device and detection method, including a laser, a three-way valve, a temperature control box, a chromatographic column, a discharge ion source, a reaction tube, a transition cavity, a mass spectrometry cavity, an ion detection mass spectrometry, a transition cavity molecular pump, a mass spectrometry cavity molecular pump, a pre-stage pump, a gas source, a sampling tube, a multi-channel power supply, a fixed rod and a detection platform, etc.; the detection method of the present invention is that the non-volatile organic matter is laser vaporized and then subjected to proton transfer reaction mass spectrometry detection, so as to realize its detection of non-volatile organic matter. Proton transfer reaction mass spectrometry can directly sample and detect gaseous volatile organic matter, but it cannot directly detect non-volatile organic matter (the boiling point is higher than 350°C under normal pressure, and it mostly exists in solid state). The present invention can not only solve the problem that proton transfer reaction mass spectrometry cannot detect non-volatile organic matter, but also realize its identification of non-volatile organic matter with the same molecular weight by introducing chromatography.

Description

Technical Field

[0001] The invention belongs to the field of analysis and detection, and in particular relates to a device and method for detecting non-volatile organic matter by laser analysis and proton transfer reaction mass spectrometry. Background Art

[0002] Proton transfer reaction mass spectrometry is a chemical ionization mass spectrometry technique based on the principle of ion-molecule reaction. The reactive ion is usually H3O + If the proton affinity of the volatile organic compound M is greater than that of H2O, it can be combined with H3O + Proton transfer reaction (H3O + +M—>MH + +H2O), which is ionized into the protonated ion peak MH + MH + Finally, it can be detected by mass spectrometry to obtain molecular weight and concentration information. This technology has the advantages of high sensitivity, fast response, soft ionization, and no need for calibration. In recent years, it has been increasingly valued in the field of volatile organic compound monitoring and analysis.

[0003] Although proton transfer reaction mass spectrometry has been widely used in the field of volatile organic compound detection, it has long been plagued by two technical bottlenecks: (1) it cannot directly measure solid organic matter; (2) it cannot distinguish substances with the same molecular weight. Technical bottleneck (1) is that proton transfer reaction mass spectrometry requires organic matter to enter the reaction tube in gaseous form. Domestic and foreign researchers use liquid spray method (Anal. Chem. 2016, 88: 3144–3148), membrane extraction method (Analytica Chimica Acta, 2011, 706: 128-134), bubbling method (Anal. Chem., 2009, 81: 9021-9026) and other methods to extract organic matter from liquid and vaporize it for sampling, which can realize online detection of organic matter in liquid. However, for solid non-volatile organic matter, proton transfer reaction mass spectrometry technology is still unable to perform rapid direct online measurement. Technical bottleneck (2) is that the proton transfer reaction mass spectrometry technology itself only provides the mass-to-charge ratio information of the detected substance, and therefore cannot identify substances with the same molecular weight, such as isomers. In order to solve technical bottleneck (2), foreign researchers introduced gas chromatography (GC) into proton transfer reaction mass spectrometry technology (Environmental Science & Technology, 2003, 37: 2494-2501), which can realize the identification of substances with the same molecular weight, but it is currently limited to the identification of substances with the same molecular weight in volatile organic compounds. Summary of the invention

[0004] The technical problem solved by the present invention is to overcome the technical bottleneck that the existing proton transfer reaction mass spectrometry technology cannot directly detect non-volatile organic compounds, and provide a non-volatile organic compound detection device and detection method for laser analysis and proton transfer reaction mass spectrometry. The non-volatile organic compounds are vaporized by laser, and the vaporized non-volatile organic compounds can be directly introduced into the reaction tube or introduced into the reaction tube after GC pre-separation under the switching control of the three-way valve (the identification of substances with the same molecular weight can be realized), and the reaction ions H3O are prepared by the discharge ion source. + 、CH5 + or NH4 + As reaction ions, they are introduced into the reaction tube under the action of the electric field. The non-volatile organic matter in the gas to be tested undergoes chemical ionization reaction with the reaction ions in the reaction tube, thereby achieving efficient ionization of the non-volatile organic matter. After detection by a mass spectrometer, the molecular weight and concentration information are obtained, thereby realizing the detection of the non-volatile organic matter.

[0005] The technical solution of the present invention:

[0006] A non-volatile organic matter detection device for laser analysis and proton transfer reaction mass spectrometry comprises a laser 1, a three-way valve 2, a temperature control box 3, a chromatographic column 4, a discharge ion source 5, a reaction tube 6, a transition chamber 7 and a mass spectrometry chamber 8; the laser 1 is fixed on a detection platform 18 by a fixing rod 17; the inlet of the three-way valve 2 is connected to a first injection tube 14a, the first outlet of the three-way valve is connected to the reaction tube 6 via a second injection tube 14b, the second outlet of the three-way valve is connected to the inlet of the chromatographic column 4, and the outlet of the chromatographic column 4 is connected to the reaction tube 6; the discharge ion source 5, the reaction tube 6, the transition chamber 7 and the mass spectrometry chamber 8 are coaxially arranged; the right end of the discharge ion source 5 is communicated with the left end of the reaction tube 6 through a coaxial hole; the transition chamber 7 is between the reaction tube 6 and the mass spectrometry chamber 8, and the transition chamber 7, the reaction tube 6 and the mass spectrometry chamber 8 are communicated through a coaxial hole; the chromatographic column 4 is inside the temperature control box 3.

[0007] In the present invention, the term "hard-to-volatile organic matter" refers to organic matter having a boiling point higher than 350° C. at normal pressure. Hard-to-volatile organic matter mostly exists in a solid state at normal temperature and pressure.

[0008] Specifically, a non-volatile organic matter detection device for laser analysis and proton transfer reaction mass spectrometry comprises a laser 1, a three-way valve 2, a temperature control box 3, a chromatographic column 4, a discharge ion source 5, a reaction tube 6, a transition chamber 7, a mass spectrometer cavity 8, an ion detection mass spectrometer 9, a transition chamber molecular pump 10, a mass spectrometer cavity molecular pump 11, a front pump 12, a gas source 13, an injection tube 14, a multi-channel power supply 15, a fixing rod 17 and a detection platform 18; the laser 1 is fixed on the detection platform 18 by the fixing rod 17; the inlet of the three-way valve 2 is connected to the first injection tube 14a, the first outlet of the three-way valve is connected to the reaction tube 6 via the second injection tube 14b, the second outlet of the three-way valve is connected to the inlet of the chromatographic column 4, and the outlet of the chromatographic column 4 is connected to the reaction tube 6; the discharge ion source 5, the reaction tube 6, the transition chamber 7, and the mass spectrometer cavity 8 are coaxially connected. The reaction tube 6 is composed of a plurality of insulating gaskets and a plurality of electrodes alternately arranged, and is connected to the injection tube 14 and the chromatographic column 4; the right end of the discharge ion source 5 is connected to the left end of the reaction tube 6 through a coaxial hole; the transition chamber 7 is between the reaction tube 6 and the mass spectrometry chamber 8, and the transition chamber 7, the reaction tube 6 and the mass spectrometry chamber 8 are connected through coaxial holes; the ion detection mass spectrometer 9 is inside the mass spectrometry chamber 8, and the ion detection inlet of the ion detection mass spectrometer 9 is coaxial with the front end hole of the mass spectrometry chamber 8; the inlet of the mass spectrometry chamber molecular pump 11 is connected to the mass spectrometry chamber 8, and the front stage pump 12 is respectively connected to the outlet of the transition chamber molecular pump 10 and the outlet of the mass spectrometry chamber molecular pump 11, and the inlet of the transition chamber molecular pump 10 is connected to the transition chamber 7; the multi-channel power supply 15 is respectively connected to the discharge ion source 5 and the reaction tube 6 through wires; the chromatographic column 4 is inside the temperature control box 3.

[0009] The wavelength of the laser 1 is 1.1-3 μm, which has a good absorption wavelength for water and is conducive to the vaporization of non-volatile organic matter on the surface or inside of water-containing substrates, such as agricultural residues on the surface of plants, animal tissues, etc.

[0010] The temperature in the temperature control box 3 is adjustable within the range of 50° C. to 300° C., which can improve the separation effect of the chromatographic column.

[0011] The multi-channel power supply 15 has multiple channels of high-voltage DC power outputs.

[0012] The gas pressure in the discharge ion source 5 is 5Pa to 500Pa; the gas pressure in the reaction tube 6 is in the range of 60Pa to 500Pa, and the effective electric field in the reaction tube 6 is in the range of 10V / cm to 700V / cm. The most sensitive detection effect can be obtained according to different vacuum pumping speeds and molecular characteristics of different objects to be detected.

[0013] The gas source 13 is water vapor, methane gas or ammonia gas, and the gas flow rate is 0.5 ml / min to 40 ml / min. The strongest reactive ions can be obtained according to different vacuum pump speed configurations.

[0014] The diameter of the hole between the discharge ion source 5 and the reaction tube 6 is 1 mm to 20 mm; the diameter of the hole between the transition chamber 7 and the reaction tube 6 is 0.1 mm to 5 mm; the diameter of the hole between the transition chamber 7 and the mass spectrometer chamber 8 is 0.1 mm to 5 mm. The corresponding hole diameter can be selected according to different vacuum pumping speeds to ensure both the working pressure of the ion detection mass spectrometer 9 and the passing efficiency of ions.

[0015] The sample injection tube 14 is heat-insulated, and the temperature of the sample injection tube 14 is 30° C. to 150° C. The reaction tube 6 is heat-insulated, and the temperature of the reaction tube 6 is 30° C. to 150° C. Different temperatures can be selected according to different types of test substances, which can ensure as little residue as possible and prevent the test substance from thermal decomposition.

[0016] The ion detection mass spectrometer 9 is a quadrupole mass spectrometer, a time-of-flight mass spectrometer, an ion trap mass spectrometer, a Fourier transform ion cyclotron resonance mass spectrometer or a magnetic mass spectrometer detection system.

[0017] The present invention also provides a method for detecting non-volatile organic matter by laser analysis and proton transfer reaction mass spectrometry, using a device as described in any of the above items, and the method comprises the following steps: a laser 1 emits laser light to the surface of the non-volatile organic matter 16 to vaporize it, and the vaporized non-volatile organic matter 16 directly enters the reaction tube 6 through the second injection tube 14b under the switching control of the three-way valve 2, or is pre-separated by the chromatographic column 4 before entering the reaction tube 6; the discharge gas in the gas source 13 is introduced into the discharge ion source 5 to prepare reactive ions, and the reactive ions are introduced into the reaction tube 6 under the action of the electric field, and in the reaction tube 6, the reactive ions undergo chemical ionization reaction with the non-volatile organic matter 16 to be detected to obtain product ions, and all product ions and unconsumed reactive ions pass through the hole communicating between the reaction tube 6 and the transition chamber 7 under the action of the guided electric field in the reaction tube 6, and then pass through the transition chamber 7 to enter the mass spectrometry chamber 8, and finally are detected by the ion detection mass spectrometer 9.

[0018] Specifically, the detection method of the present invention is as follows: the laser 1 vaporizes the non-volatile organic matter 16, and the vaporized non-volatile organic matter 16 directly enters the reaction tube 6 through the second injection tube 14b under the switching control of the three-way valve 2, or is pre-separated by the chromatographic column 4 before entering the reaction tube 6; in addition, the discharge gas water vapor, methane gas or ammonia gas in the gas source 13 is passed into the discharge ion source 5 for discharge to prepare the reaction ion A + , is introduced into the reaction tube 6 under the action of the electric field. In the reaction tube 6, the reaction ions A + Chemical ionization reaction occurs with the non-volatile organic compound 16 (M) to be measured: A + +M→B + + C, where C is the neutral molecule generated by the reaction, and the product ion B + and unconsumed reagent ions A+ Under the action of the guided electric field in the reaction tube 6, the non-volatile organic compounds pass through the hole between the reaction tube 6 and the transition chamber 7, then pass through the transition chamber 7, enter the mass spectrometer chamber 8, and are finally detected by the ion detection mass spectrometer 9, thereby realizing the detection of non-volatile organic compounds. Under the switching control of the three-way valve 2, the non-volatile organic compounds of a single component directly enter the reaction tube 6 after vaporization, which can realize the real-time online detection of non-volatile organic compounds; non-volatile organic compounds with the same molecular weight enter the reaction tube 6 after being separated by the chromatographic column 4, which can realize the identification of non-volatile organic compounds with the same molecular weight by proton transfer reaction mass spectrometry.

[0019] The differences and advantages of the present invention compared with the prior art are:

[0020] (1) In the proton transfer reaction mass spectrometry, the sample to be tested is required to be sampled in the gaseous state, so the gaseous organic matter with strong volatility can be directly measured, but the solid organic matter that is difficult to volatilize cannot be directly measured. In addition, the proton transfer reaction mass spectrometry itself can only obtain the mass-to-charge ratio information of the substance to be tested, and thus cannot identify substances with the same molecular weight. The present invention combines laser desorption sampling with proton transfer reaction mass spectrometry technology, vaporizes the solid difficult volatile organic matter by laser, realizes the vaporization sampling of the solid difficult volatile organic matter, and pre-separates the difficult volatile organic matter with the same molecular weight by chromatography, and finally realizes the real-time online detection of single-component difficult volatile organic matter by mass spectrometry, and the identification of difficult volatile organic matter with the same molecular weight. The present invention mainly includes a laser, a three-way valve, a temperature control box, a chromatographic column, a discharge ion source, a reaction tube, a transition cavity, a mass spectrometry cavity, an ion detection mass spectrometer, a transition cavity molecular pump, a mass spectrometry cavity molecular pump, a pre-stage pump, a gas source, an injection tube, a multi-channel power supply, a fixed rod and a detection platform. The sampling method having both direct sampling and chromatographic separation sampling is different from the prior art.

[0021] (2) The innovation of the present invention lies in: combining laser desorption sampling with proton transfer reaction mass spectrometry to solve the problem that the existing proton transfer reaction mass spectrometry technology cannot directly detect solid non-volatile organic compounds. Compared with the existing proton transfer reaction mass spectrometry technology, the biggest advantage of the present invention is that it can not only detect solid non-volatile organic compounds, but also identify substances with the same molecular weight; in addition, the pressure at the outlet of the chromatographic column in the present invention is the pressure in the reaction tube (60Pa~500Pa). Compared with one atmosphere of pressure at the outlet of a conventional chromatographic column, the low pressure will speed up the separation speed of the chromatographic column, thereby shortening the detection time of the substance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a low-volatile organic matter detection device for laser desorption sampling proton transfer reaction mass spectrometry of the present invention;

[0023] Figure 2 Mass spectra of solid drug detection under different laser energies.

[0024] Figure 1 In the figure, 1-laser, 2-three-way valve, 3-temperature control box, 4-chromatographic column, 5-discharge ion source, 6-reaction tube, 7-transition chamber, 8-mass spectrometer chamber, 9-ion detection mass spectrometer, 10-transition chamber molecular pump, 11-mass spectrometer chamber molecular pump, 12-fore stage pump, 13-gas source, 14a-first injection tube, 14b-second injection tube, 15-multi-channel power supply, 16-difficult volatile organic matter, 17-fixed rod, 18-detection platform. DETAILED DESCRIPTION

[0025] like Figure 1As shown, a laser analysis sampling proton transfer reaction mass spectrometry non-volatile organic matter detection device of the present invention includes: a laser 1, a three-way valve 2, a temperature control box 3, a chromatographic column 4, a discharge ion source 5, a reaction tube 6, a transition chamber 7, a mass spectrometer cavity 8, an ion detection mass spectrometer 9, a transition chamber molecular pump 10, a mass spectrometer cavity molecular pump 11, a pre-stage pump 12, a gas source 13, a sampling tube 14, a multi-way power supply 15, a non-volatile organic matter 16, a fixing rod 17 and a detection platform 18. The laser 1 is fixed on the detection platform 18 by the fixing rod 17. The three-way valve 2 includes an inlet of the three-way valve, a first outlet of the three-way valve and a second outlet of the three-way valve. The inlet of the three-way valve 2 is connected to the first sampling tube 14a. The first outlet of the three-way valve is connected to the second sampling tube 14b. The second outlet of the three-way valve is connected to the inlet of the chromatographic column 4. The outlet of the chromatographic column 4 is connected to the reaction tube 6. The reaction tube 6 is composed of a plurality of insulating gaskets and a plurality of electrodes alternately arranged. The reaction tube 6 is connected to the second sample injection tube 14b. The reaction tube 6 is connected to the chromatographic column 4. The discharge ion source 5, the reaction tube 6, the transition chamber 7 and the mass spectrometer chamber 8 are placed coaxially. The right end of the discharge ion source 5 is connected to the left end of the reaction tube 6 through a coaxial hole. The transition chamber 7 is between the reaction tube 6 and the mass spectrometer chamber 8, and the transition chamber 7, the reaction tube 6 and the mass spectrometer chamber 8 are connected through coaxial holes. The hole on the mass spectrometer chamber 8 is located at the front end of the mass spectrometer chamber 8. The ion detection mass spectrometer 9 has an ion detection inlet. The ion detection mass spectrometer 9 is inside the mass spectrometer chamber 8, and the ion detection inlet of the ion detection mass spectrometer 9 is coaxial with the front end hole of the mass spectrometer chamber 8; the inlet of the mass spectrometer chamber molecular pump 11 is connected to the mass spectrometer chamber 8, and the front stage pump 12 is respectively connected to the outlet of the transition chamber molecular pump 10 and the outlet of the mass spectrometer chamber molecular pump 11. The multi-channel power supply 15 is respectively connected to the discharge ion source 5 and the reaction tube 6 through electric wires. The inlet of the transition chamber molecular pump 10 is connected to the transition chamber 7. The gas source 13 is connected to the discharge ion source 5. The first injection tube 14a is located directly above the non-volatile organic matter 16. The non-volatile organic matter 16 is placed on the surface of the detection platform 18. The laser 1 is used to vaporize the non-volatile organic matter 16. The distance between the laser 1 and the surface of the detection platform 18, as well as the inclination angle of the laser 1, are adjusted by the fixing rod 17 to ensure that the output light of the laser 1 can directly illuminate the non-volatile organic matter 16. The discharge ion source 5 includes a discharge electrode and a source guide electrode. The three-way valve 2 is a manual three-way valve or a three-way solenoid valve. The chromatographic column 4 is inside the temperature control box 3.

[0026] The method of the present invention is implemented as follows: the laser 1 vaporizes the non-volatile organic matter 16 (the boiling point is higher than 350°C under normal pressure, and it mostly exists in a solid state under normal temperature and pressure), and the vaporized non-volatile organic matter 16 enters the three-way valve 2 through the first injection tube 14a, and under the switching control of the three-way valve 2, directly enters the reaction tube 6 through the second injection tube 14b, or first passes through the chromatographic column 4 for pre-separation and then enters the reaction tube 6; in addition, the discharge gas (water vapor, methane gas or ammonia gas) in the gas source 13 is passed into the discharge ion source 5 for discharge, and the reaction ion A is prepared. + , is introduced into the reaction tube 6 under the action of the electric field. In the reaction tube 6, the reaction ions A + Chemical ionization reaction occurs with the non-volatile organic compound 16 (M) to be measured: A + +M→B + + C, where C is the neutral molecule generated by the reaction, and the product ion B + and unconsumed reagent ions A + Under the action of the guided electric field in the reaction tube 6, the non-volatile organic compounds pass through the hole between the reaction tube 6 and the transition chamber 7, then pass through the transition chamber 7, enter the mass spectrometer chamber 8, and are finally detected by the ion detection mass spectrometer 9, thereby realizing the detection of non-volatile organic compounds. Under the switching control of the three-way valve 2, the non-volatile organic compounds of a single component directly enter the reaction tube 6 after vaporization, which can realize the real-time online detection of non-volatile organic compounds; non-volatile organic compounds with the same molecular weight enter the reaction tube 6 after being separated by the chromatographic column 4, which can realize the identification of non-volatile organic compounds with the same molecular weight by proton transfer reaction mass spectrometry.

[0027] In order to obtain a better vaporization effect of the non-volatile organic matter, the fixing rod 17 is a telescopic fixing rod, and the telescopic length is adjustable within the range of 5 cm to 50 cm.

[0028] In order to obtain better laser analysis and chromatographic separation effects, the wavelength of the laser 1 is adjustable within the range of 1.1 to 3 μm, which has a good absorption wavelength for water; the temperature in the temperature control box 3 is adjustable within the range of 50° C. to 300° C.

[0029] In order to obtain better reaction ion intensity and detection sensitivity, the gas source 13 can be water vapor, methane gas or ammonia gas, and the gas flow rate is 0.5ml / min to 40ml / min; the gas pressure range in the discharge ion source 5 is 5Pa to 500Pa. The gas pressure range in the reaction tube 6 is 60Pa to 500Pa, and the effective electric field range in the reaction tube 6 is 10V / cm to 700V / cm.

[0030] According to different vacuum system configurations, the diameter of the hole between the discharge ion source 5 and the reaction tube 6 is between 1mm and 20mm; the diameter of the hole between the transition chamber 7 and the reaction tube 6 is between 0.1mm and 5mm; the diameter of the hole between the transition chamber 7 and the mass spectrometer chamber 8 is between 0.1mm and 5mm.

[0031] In order to reduce the residue of the analyte and ensure that the analyte does not decompose thermally, the first injection tube 14a and the second injection tube 14b are heat-insulated, and the temperature of the first injection tube 14a and the second injection tube 14b is between 30°C and 150°C; the reaction tube 6 is heat-insulated, and the temperature of the reaction tube 6 is between 30°C and 150°C.

[0032] To meet different detection requirements, the chromatographic column 4 can be selected from a conventional chromatographic column (taking toluene as an example, the peak elution time is more than 5 minutes) or a fast chromatographic column (taking toluene as an example, the peak elution time is within 2 minutes).

[0033] According to the ion detection requirements, the ion detection mass spectrometer 9 can be a quadrupole mass spectrometer, a time-of-flight mass spectrometer, an ion trap mass spectrometer, a Fourier transform ion cyclotron resonance mass spectrometer or a magnetic mass spectrometer detection system.

[0034] Figure 2 The mass spectra of solid drugs detected by proton transfer reaction mass spectrometry under different laser energies are given. In Figure (a), 0mJ means that the laser is not turned on. At this time, only two mass peaks of volatile organic compounds, m / z 45 and 59 (possibly acetaldehyde and acetone), appear in the mass spectrum. As the laser energy gradually increases (from 40mJ to 100mJ), more and more mass peaks appear in the mass spectrum, and the intensity also increases, indicating that under the action of laser analysis, proton transfer reaction mass spectrometry has detected many non-volatile organic compounds.

[0035] Parts not described in detail in the specification of the present invention belong to the well-known technology in the art.

[0036] The above descriptions are only some specific implementation methods of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any person familiar with the art within the technical scope disclosed in the present invention should be covered within the protection scope of the present invention.

Claims

1. A laser analysis and proton transfer reaction mass spectrometry low-volatile organic compound detection device, characterized in that: The invention comprises a laser (1), a three-way valve (2), a temperature control box (3), a chromatographic column (4), a discharge ion source (5), a reaction tube (6), a transition chamber (7) and a mass spectrometer chamber (8); the laser (1) is fixed on a detection platform (18) via a fixing rod (17); the inlet of the three-way valve (2) is connected to a first injection tube (14a), the first outlet of the three-way valve is connected to the reaction tube (6) via a second injection tube (14b), and the second outlet of the three-way valve is connected to an inlet of the chromatographic column (4). The outlet of the chromatographic column (4) is connected to the reaction tube (6); the discharge ion source (5), the reaction tube (6), the transition chamber (7) and the mass spectrometer chamber (8) are coaxially arranged; the right end of the discharge ion source (5) is connected to the left end of the reaction tube (6) through a coaxial hole; the transition chamber (7) is between the reaction tube (6) and the mass spectrometer chamber (8), and the transition chamber (7), the reaction tube (6) and the mass spectrometer chamber (8) are connected through a coaxial hole; the chromatographic column (4) is inside the temperature control box (3).

2. The laser desorption proton transfer reaction mass spectrometry low-volatile organic compound detection device according to claim 1, characterized in that: The wavelength of the laser (1) is between 1.1 and 3 μm.

3. The laser desorption proton transfer reaction mass spectrometry low-volatile organic compound detection device according to claim 1, characterized in that: The temperature in the temperature control box (3) is adjustable within the range of 50-300°C.

4. The laser desorption proton transfer reaction mass spectrometry low-volatile organic compound detection device according to claim 1, characterized in that: The detection device further comprises a gas source (13) and a multi-channel power supply (15), wherein the multi-channel power supply (15) is respectively connected to the discharge ion source (5) and the reaction tube (6) via electric wires; the gas source (13) is connected to the discharge ion source (5); and the gas pressure in the discharge ion source (5) ranges from 5 Pa to 500 Pa.

5. The laser desorption proton transfer reaction mass spectrometry low-volatile organic compound detection device according to claim 1, characterized in that: The reaction tube (6) is composed of a plurality of insulating gaskets and a plurality of electrodes alternately arranged in an alternating manner; the gas pressure in the reaction tube (6) ranges from 60 Pa to 500 Pa, and the effective electric field in the reaction tube (6) ranges from 10 V / cm to 700 V / cm; the reaction tube (6) is subjected to heat preservation treatment, and the temperature of the reaction tube (6) ranges from 30° C. to 150° C.

6. The laser desorption proton transfer reaction mass spectrometry low-volatile organic compound detection device according to claim 1, characterized in that: The detection device further comprises an ion detection mass spectrometer (9), a mass spectrometer cavity molecular pump (11) and a pre-stage pump (12); the ion detection mass spectrometer (9) is inside the mass spectrometer cavity (8), and the ion detection inlet of the ion detection mass spectrometer (9) is coaxial with the front end hole of the mass spectrometer cavity (8); the inlet of the mass spectrometer cavity molecular pump (11) is connected to the mass spectrometer cavity (8), the pre-stage pump (12) is respectively connected to the outlet of the transition cavity molecular pump (10) and the outlet of the mass spectrometer cavity molecular pump (11), and the inlet of the transition cavity molecular pump (10) is connected to the transition cavity (7).

7. The laser desorption proton transfer reaction mass spectrometry low-volatile organic compound detection device according to claim 1, characterized in that: The diameter of the hole communicating between the discharge ion source (5) and the reaction tube (6) is 1 mm to 20 mm; the diameter of the hole communicating between the transition chamber (7) and the reaction tube (6) is in the range of 0.1 mm to 5 mm; and the diameter of the hole communicating between the transition chamber (7) and the mass spectrometer chamber (8) is in the range of 0.1 mm to 5 mm.

8. The laser desorption proton transfer reaction mass spectrometry low-volatile organic compound detection device according to claim 4, characterized in that: The multi-channel power supply (15) has multiple channels of high-voltage direct current power outputs.

9. The laser desorption proton transfer reaction mass spectrometry low-volatile organic compound detection device according to claim 6, characterized in that: The ion detection mass spectrometer (9) is a quadrupole mass spectrometer, a time-of-flight mass spectrometer, an ion trap mass spectrometer, a Fourier transform ion cyclotron resonance mass spectrometer or a magnetic mass spectrometer detection system.

10. The laser desorption proton transfer reaction mass spectrometry low-volatile organic compound detection device according to claim 4, characterized in that: The gas source (13) is water vapor, methane gas or ammonia gas, and the gas flow rate is 0.5 ml / min~40 ml / min.

11. The laser desorption proton transfer reaction mass spectrometry low-volatile organic compound detection device according to claim 1, characterized in that: The first injection tube (14a) and the second injection tube (14b) are both subjected to heat preservation treatment, and the temperature of the first injection tube (14a) and the second injection tube (14b) are both 30°C to 150°C.

12. The laser desorption proton transfer reaction mass spectrometry low-volatile organic compound detection device according to claim 1, characterized in that: The fixing rod (17) is a telescopic fixing rod with a telescopic length of 5 cm to 50 cm.

13. A method for detecting low-volatile organic compounds by laser desorption-injection proton transfer reaction mass spectrometry, characterized in that: Using the device according to any one of claims 1 to 12, the method comprises the following steps: The laser (1) emits laser light to the surface of the non-volatile organic matter (16) to vaporize it. The vaporized non-volatile organic matter (16) directly enters the reaction tube (6) through the second injection tube (14b) under the switching control of the three-way valve (2), or is pre-separated by the chromatographic column (4) before entering the reaction tube (6). The discharge gas in the gas source (13) is introduced into the discharge ion source (5) to prepare reaction ions. The reaction ions are introduced into the reaction tube (6) under the action of the electric field. In the reaction tube (6), the reaction ions react with the non-volatile organic matter (16) to be measured to obtain product ions. All product ions and unconsumed reaction ions pass through the hole between the reaction tube (6) and the transition chamber (7) under the action of the guided electric field in the reaction tube (6), then pass through the transition chamber (7) to enter the mass spectrometer chamber (8), and are finally detected by the ion detection mass spectrometer (9).

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