A device and method for real-time online analysis of semi-volatile organic contaminants

Abstract

The present application belongs to the technical field of on-line analysis of machine pollutants, and particularly relates to a device and method for real-time on-line analysis of difficult volatile organic pollutants. The device comprises a sample injection module, a vacuum ultraviolet lamp, an ionization source cavity, a repelling electrode, an ion funnel, a mass analyzer and a vacuum pumping module. The ionization source cavity is provided with a sample injection port, a vacuum air outlet and an ion output port. The vacuum ultraviolet lamp, the repelling electrode and the ion funnel are sequentially and spacedly arranged in the ionization source cavity along the axis direction of the ion output port, and the ion funnel is close to the ion output port. The sample injection module is arranged at the sample injection port. The vacuum pumping module is arranged on the vacuum air outlet. The ion output port is connected with the mass analyzer. A direct current voltage is applied to the repelling electrode, and a direct current voltage and a radio frequency voltage are applied to the ion funnel. The present application can focus ions with a large initial distribution area, thereby further improving the detection sensitivity to meet the detection requirements of trace difficult volatile organic pollutants.

Description

Technical Field

[0001] The present invention belongs to the technical field of online analysis of organic pollutants, and in particular relates to a device and method for real-time online analysis of non-volatile organic pollutants. Background Art

[0002] Photoionization is an attractive soft ionization technology, offering advantages such as excellent ionization efficiency, high molecular ion yields, and easy spectra interpretation. Furthermore, according to Beer-Ludwig's law, sensitivity can be further enhanced by increasing gas pressure, light flux, and optical pathlength. Consequently, photoionization is widely used in environmental analysis, clinical diagnostics, and industrial process monitoring.

[0003] When the pressure within the photoionization source is high (>100 Pa), collisional divergence between molecules and ions and the small aperture between the vacuum differential chambers become the primary factors limiting ion utilization. Therefore, an efficient ion transport system is a key technology for improving sensitivity. Ion funnels operate at pressures ranging from 1 to 1000 Pa, matching the operating pressure of the ionization source. Therefore, they are often used as ion focusing devices within the source, improving sensitivity by an order of magnitude.

[0004] Phthalates, a major plasticizer, are widely used in hundreds of products, including toys, food packaging materials, medical blood bags, and personal care products such as nail polish, hair spray, soap, and shampoo. However, the environmental health hazards posed by these compounds have recently garnered widespread attention in environmental science, public health, and even the general public. However, when analyzing volatile organic pollutants like phthalates, the detection limits remain unsatisfactory, even using a photoionization source coupled with an ion funnel, due to their extremely low volatile content. Therefore, there is an urgent need for a device and method for the real-time, online analysis of volatile organic pollutants. Summary of the Invention

[0005] In view of the above problems, the object of the present invention is to provide a device and method for real-time online analysis of non-volatile organic pollutants, so as to solve the problem that the detection limit is difficult to meet the requirements when analyzing non-volatile organic pollutants in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] On the one hand, the present invention provides a device for real-time online analysis of non-volatile organic pollutants, comprising an injection module, a vacuum ultraviolet lamp, an ionization source cavity, a repeller electrode, an ion funnel, a mass analyzer and a vacuum module, wherein the ionization source cavity is provided with an injection port, a vacuum exhaust port and an ion output port, the vacuum ultraviolet lamp, the repeller electrode and the ion funnel are arranged in the ionization source cavity in sequence along the axis direction of the ion output port, and the ion funnel is close to the ion output port, and the light emitted by the light source end of the vacuum ultraviolet lamp passes through the repeller electrode and the ion funnel in sequence; the injection module is arranged at the injection port to transport the sample to be tested into the ionization source cavity; the vacuum module is arranged on the vacuum exhaust port for vacuuming the ionization source cavity; the ion output port is externally connected to the mass analyzer; a DC voltage is applied to the repeller electrode, and a DC voltage and a radio frequency voltage are applied to the ion funnel; the sample is ionized under the action of the vacuum ultraviolet lamp, and the sample ions are focused and transmitted to the mass analyzer under the action of the repeller electrode and the ion funnel to achieve final detection and analysis.

[0008] The ion funnel comprises a plurality of annular flat plate funnel electrodes which are arranged in parallel and at equal intervals and each have a circular through hole. The aperture of the circular through hole of each annular flat plate funnel electrode decreases in sequence along the emitting direction of the vacuum ultraviolet lamp.

[0009] The DC voltage applied to the repeller electrode and each annular flat funnel electrode in the ion funnel is sequentially reduced along the direction of light emitted from the light source end of the vacuum ultraviolet lamp to form a DC gradient electric field;

[0010] Radio frequency voltage is applied to each annular flat funnel electrode in the ion funnel, and the peak-to-peak amplitudes of the radio frequencies on any two adjacent annular flat funnel electrodes are equal and the phases are opposite.

[0011] The gradient electric field of the DC gradient electric field is 2-20 V / cm; the radio frequency frequency of the radio frequency voltage is 0.5-5 MHz, and the radio frequency peak-to-peak value is 10-800 V; the number of the annular flat funnel electrodes is N, and N is an even number.

[0012] The repeller electrode is an annular flat plate structure with a circular through hole in the middle; the thickness of the repeller electrode is 2-4 mm, and the diameter of the circular through hole in the middle is 4-10 mm;

[0013] The thickness of each annular flat plate funnel electrode in the ion funnel is 0.5-1 mm, and the diameter of the circular through hole in the middle is 1-20 mm;

[0014] The repeller electrode and each of the annular flat plate funnel electrodes are made of conductive metal or a flat plate with a conductive metal layer plated on its surface.

[0015] The vacuum ultraviolet lamp is a low-pressure krypton lamp with a large light window diameter, and the photon emission diameter is 6-12 mm.

[0016] The injection module includes an injection capillary, a volatilization chamber, and a sample delivery tube, wherein an air inlet and an air outlet are respectively provided on both sides of the volatilization chamber. The air inlet is externally connected to a flow meter, which is used to control the flow of carrier gas entering the volatilization chamber; the air outlet is tightly connected to one end of the sample delivery tube, and the other end of the sample delivery tube is tightly connected to one end of the injection capillary via a three-hole joint. The other end of the injection capillary penetrates into the ionization source cavity through the injection port and extends to the area between the repeller electrode and the ion funnel; the sample to be tested is placed in the volatilization chamber.

[0017] The volatilization chamber, the sample delivery tube, the three-hole joint and the injection capillary are all wrapped by a heating device, and the temperature of the heating device can be adjusted between 0-200 °C.

[0018] The carrier gas flowing through the flow meter is nitrogen or helium, the gas flow rate is 50-200 ml / min, and the carrier gas flow rate is greater than the injection volume of the injection capillary;

[0019] The inner diameter of the sample delivery tube is 3-6 mm, and the inner diameter of the injection capillary is 100-250 μm.

[0020] The vacuum pumping module includes an air pressure valve and a vacuum mechanical pump; the vacuum pumping port of the ionization source cavity is connected to the air pressure valve and the vacuum mechanical pump in sequence from the inside to the outside;

[0021] The air pressure in the ionization source cavity is between 10-1000 Pa and is regulated by an air pressure valve and a vacuum mechanical pump.

[0022] Another aspect of the present invention provides a method for real-time online analysis of non-volatile organic pollutants using the above-mentioned device. The method comprises placing a sample to be tested in a volatilization chamber, setting a heating temperature, and introducing a carrier gas at a fixed flow rate into the volatilization chamber through a flowmeter. The carrier gas carries the volatile components of the sample to be tested and passes through a sample delivery tube, a three-hole connector, and an injection capillary tube in sequence before entering the ionization source cavity. The non-volatile components with low content are first efficiently ionized under the action of a vacuum ultraviolet lamp with a large photon emission diameter. Thereafter, the sample ions are effectively focused under the action of a repeller electrode and an ion funnel and transmitted to a mass analyzer for final detection and analysis.

[0023] The advantages and beneficial effects of the present invention are: by combining an ion funnel with a photoionization source with a larger light-emitting area, the present invention can focus ions with a larger initial distribution area due to the ion funnel's better focusing effect, thereby further improving the detection sensitivity to meet the detection needs of trace non-volatile organic pollutants. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the structure of a device for real-time online analysis of low-volatile organic pollutants according to the present invention;

[0025] Figure 2 A schematic diagram of the structure of the photoionization source of the present invention established using SIMION;

[0026] Figure 3 SIMION simulation result diagram of the effect of using a photoionization source with a larger light-emitting area on sensitivity in an embodiment of the present invention.

[0027] In the figure: 1-injection capillary, 2-vacuum ultraviolet lamp, 3-ionization source chamber, 4-repelling electrode, 5-air pressure valve, 6-vacuum mechanical pump, 7-ion funnel, 8-mass analyzer, 9-flow meter, 10-volatilization chamber, 11-sample to be tested, 12-sample delivery tube, 13-three-hole connector. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] See also Figure 1 As shown, the present invention provides a device for real-time online analysis of non-volatile organic pollutants, comprising a sampling module, a vacuum ultraviolet lamp 2, an ionization source chamber 3, a repeller electrode 4, an ion funnel 7, a mass analyzer 8 and a vacuum module, wherein the ionization source chamber 3 is provided with a sampling port, a vacuum exhaust port and an ion output port, the vacuum ultraviolet lamp 2, the repeller electrode 4 and the ion funnel 7 are sequentially arranged in the ionization source chamber 3 along the axis direction of the ion output port, and the ion funnel 7 is close to the ion output port, and the light emitted by the light source emitting end of the vacuum ultraviolet lamp 2 passes through the repeller electrode 4 and the ion funnel 7 in sequence, that is, the vacuum ultraviolet lamp 2 is located at the repeller electrode 4. 4 is located on the side of the repeller electrode 4 away from the ion output port, and the ion funnel 7 is located on the side of the repeller electrode 4 close to the ion output port; the sampling module is arranged at the sampling port to transport the sample to be tested into the ion source cavity 3; the vacuum pumping module is arranged on the vacuum pumping port to vacuum the ion source cavity 3; the ion output port is externally connected to the mass analyzer 8; a DC voltage is applied to the repeller electrode 4, and a DC voltage and a radio frequency voltage are applied to the ion funnel 7; the sample is ionized under the action of the vacuum ultraviolet lamp 2, and the sample ions are focused and transmitted to the mass analyzer 8 under the action of the repeller electrode 4 and the ion funnel 7 to achieve final detection and analysis.

[0030] In an embodiment of the present invention, the injection module includes an injection capillary 1, a volatilization chamber 10, and a sample delivery tube 12. An air inlet and an air outlet are provided on opposite sides of the volatilization chamber 10. The air inlet is connected to a flow meter 9 for controlling the flow of carrier gas entering the volatilization chamber 10. The air outlet is tightly connected to one end of the sample delivery tube 12, and the other end of the sample delivery tube 12 is tightly connected to one end of the injection capillary 1 via a three-hole connector 13. The other end of the injection capillary 1 passes through the injection port into the ionization source chamber 3 and extends between the repeller electrode 4 and the ion funnel 7. The unused end of the three-hole connector 13 is used to remove excess carrier gas. A sample 11 to be tested is placed in the volatilization chamber 10. The components to be tested generated by the sample 11 in the volatilization chamber 10 are carried by the airflow through the sample delivery tube 12 and the injection capillary 1 into the ionization source chamber 3.

[0031] Furthermore, the volatilization chamber 10, the sample delivery tube 12, the three-hole connector 13 and the injection capillary 1 are all wrapped by a heating device, and the temperature of the heating device can be adjusted between 0-200°C.

[0032] Specifically, the carrier gas flowing through flowmeter 9 is nitrogen or helium, with a gas flow rate of 50-200 ml / min, and the carrier gas flow rate is greater than the sample volume injected into injection capillary 1. The inner diameter of sample delivery tube 12 is 3-6 mm, and the inner diameter of injection capillary 1 is 100-250 μm. Sample delivery tube 12 is made of polyfluoroethylene tubing. The volatilization chamber 10 is the volatilization area for the sample 11 to be tested. The axial centerline of the upper left air inlet and the axial centerline of the lower right air outlet are both parallel to the horizontal plane.

[0033] In an embodiment of the present invention, the vacuum pumping module includes an air pressure valve 5 and a vacuum mechanical pump 6; the vacuum exhaust port of the ionization source cavity 3 is connected to the air pressure valve 5 and the vacuum mechanical pump 6 in sequence from the inside to the outside; the air pressure in the ionization source cavity 3 is between 10-1000 Pa, and is jointly regulated by the air pressure valve 5 and the vacuum mechanical pump 6.

[0034] Specifically, the ionization source chamber 3 is a hollow cubic structure, with a circular vacuum pumping port and an ion output port respectively provided on the right side wall and the lower side wall, and a sample inlet provided in the middle of the left side wall.

[0035] See also Figure 1As shown, in an embodiment of the present invention, the ion funnel 7 includes a plurality of annular flat funnel electrodes arranged in parallel and at equal intervals and each having a circular through hole. The number of the annular flat funnel electrodes is N, and N is an even number. The aperture of the circular through hole of each annular flat funnel electrode decreases successively along the light emission direction of the vacuum ultraviolet lamp 2. The DC voltage applied to the repeller electrode 4 and each annular flat funnel electrode in the ion funnel 7 decreases successively along the direction of light emitted from the light source end of the vacuum ultraviolet lamp 2, and forms a DC gradient electric field with a gradient electric field of 2-20 V / cm. An RF voltage is applied to each annular flat funnel electrode in the ion funnel 7, and the RF peak-to-peak amplitudes of any two adjacent annular flat funnel electrodes are equal and opposite in phase. The RF frequency of the RF voltage is 0.5-5 MHz, and the RF peak-to-peak value is 10-800 V.

[0036] Specifically, the repeller electrode 4 is an annular flat plate structure with a circular through-hole in the center. The repeller electrode 4 is 2-4 mm thick, and the diameter of the central circular through-hole is 4-10 mm. The ion funnel 7 contains 22 annular flat plate funnel electrodes, each with a uniform thickness of 0.5-1 mm and a central circular through-hole diameter of 1-20 mm. The centerline of the circular through-hole in the repeller electrode 4, the centerlines of the circular through-holes in all the annular flat plate funnel electrodes in the ion funnel 7, the axial centerline of the ion output port, and the axial centerline of the light source emission end of the vacuum ultraviolet lamp 2 are all collinear.

[0037] Furthermore, the repeller electrode 4 and each annular flat funnel electrode are made of conductive metal or a flat plate coated with a conductive metal layer. The vacuum ultraviolet lamp 2 is a low-pressure krypton lamp with a large optical window diameter, and the photon emission diameter is 6-12 mm.

[0038] In an embodiment of the present invention, the mass analyzer 8 is a time-of-flight mass analyzer or an orbital trap mass analyzer with ultra-high resolution and a time resolution of less than 1 s, which can meet the research needs of rapidly tracking the dynamic changes of volatile substances.

[0039] Preferably, the axial centerline of the vacuum exhaust port of the ionization source chamber 3 is parallel to the horizontal plane; the axial centerline of the ion output port of the ionization source chamber 3 and the axial centerline of the light source emitting end of the vacuum ultraviolet lamp 2 are both perpendicular to the horizontal plane, and the air pressure within the ionization source chamber 3 is 450 Pa. The DC voltage applied to the repeller electrode 4 and each annular flat-plate funnel electrode of the ion funnel 7 decreases sequentially along the direction of light emitted from the light source emitting end of the vacuum ultraviolet lamp 2 to form a DC gradient electric field with a gradient electric field of 7.5 V / cm; an RF voltage is applied to each annular flat-plate funnel electrode of the ion funnel 7, and the RF peak-to-peak amplitudes of any two adjacent funnel electrodes are equal and opposite in phase; the applied RF frequency is 0.98 MHz, and the RF peak-to-peak value is 120 V.

[0040] Preferably, the thickness of the repelling electrode 4 is 3 mm, and the diameter of the central through hole is 8 mm; the thickness of each funnel electrode in the ion funnel 7 is consistent, being 0.5 mm, and the diameter of the central circular through hole is 2-18 mm; the material of each annular flat funnel electrode in the repelling electrode 4 and the ion funnel 7 is stainless steel flat plate.

[0041] The volatilization chamber 10 is a volatilization area of the sample 11 to be detected, and the axial center line of the gas inlet and the axial center line of the gas outlet are both parallel to the horizontal plane. The carrier gas flowing through the flow meter 9 is nitrogen, and the gas flow rate is 100 ml / min, which is greater than the sample amount of the sample injection capillary 1. The inner diameter of the sample delivery tube 12 is 3 mm, and the inner diameter of the sample injection capillary 1 is 250 μm. The temperature of the volatilization chamber 10, the four-fluorine tube 12, the three-hole joint 13 and the sample injection capillary 1 is set to 150 ℃. The photon emission diameter of the vacuum ultraviolet lamp 2 is 8 mm. The mass analyzer 8 is a time-of-flight mass analyzer with ultra-high resolution and time resolution less than 1 s, which can meet the research needs of rapid tracking of dynamic changes of volatile substances.

[0042] The photoionization source in the present application combines the ion funnel and the photoionization source with a larger light emission area. Since the ion funnel has good focusing effect, it can focus the ions with a larger initial distribution area, thereby further improving the detection sensitivity to meet the detection needs of trace difficult-to-volatile organic pollutants.

[0043] Another embodiment of the present application provides a method for real-time online analysis of difficult-to-volatile organic pollutants by using the device in the above embodiment. The method is as follows: the sample 11 to be detected is placed in the volatilization chamber 10, and the heating temperature is set. The carrier gas with a fixed flow rate is introduced into the volatilization chamber 10 through the flow meter 9. The volatile components of the sample 11 to be detected are carried by the carrier gas and sequentially pass through the sample delivery tube 12, the three-hole joint 13 and the sample injection capillary 1 to enter the ionization source cavity 3. The low-content difficult-to-volatile components are first ionized efficiently under the action of the vacuum ultraviolet lamp 2 with a large photon emission diameter, and then the sample ions are effectively focused and transmitted to the mass analyzer 8 under the action of the repelling electrode 4 and the ion funnel 7 to realize the final detection and analysis. Embodiment

[0044] The structure of the device in the present application is specifically referred to Figure 1 The simulation model is established under the above conditions using SIMION, and please refer to Figure 2The ion transmission efficiency is simulated, the ion mass-to-charge ratio (m / z) used in simulation is 116, the initial kinetic energy divergence is 0.5-2 eV, the initial angle divergence is 60 degrees, the ion generation region is a cylindrical region with the axial center line coinciding with the center line of the repelling electrode 4, the length of the cylindrical region is fixed at 10 mm, the distance from the point to the lower surface of the repelling electrode 4 is 6 mm, and the upper and lower diameters of the cylindrical region represent the photon emission diameter of the vacuum ultraviolet lamp 2. Assuming that the sample molecules are uniformly distributed, the number of simulated ions is set to 100, 400, 900 and 1600 according to the diameters of the ion generation cylindrical region of 2 mm, 4 mm, 6 mm and 8 mm, respectively. The simulation results are shown in Figure 3 When the peak-to-peak value of the radio frequency of the ion funnel 7 is 0 V, the number of ions passing through is 7 when the photon emission diameter is 2 mm, and the transmission efficiency is 7%; and the number of ions passing through is 25 when the photon emission diameter is 8 mm, and the transmission efficiency is 1.6%. It can be seen that without the focusing effect of the ion funnel 7, although the use of the vacuum ultraviolet lamp 2 with a large photon emission diameter can improve the sensitivity, the ion transmission efficiency is actually decreasing. When the peak-to-peak value of the radio frequency of the ion funnel 7 is 120 V, the number of ions passing through is 47 when the photon emission diameter is 2 mm, and the transmission efficiency is 47%, which is 6.7 times the signal intensity when the peak-to-peak value of the radio frequency of the ion funnel 7 is 0 V. Moreover, the increase multiple gradually increases with the increase of the photon emission diameter, and the increase multiple is 32.9 times when the photon emission diameter is 8 mm, and the transmission efficiency is 51.4% at this time. It can be seen that the combination of the ion funnel and the photoionization source with a larger light emission area is a good means to further improve the detection sensitivity.

[0045] The device and method for real-time online analysis of difficult volatile organic pollutants provided by the application are based on the super-high sensitivity photoionization source mass spectrometry technology to realize the online analysis of the difficult volatile organic pollutants possibly contained in common articles. The device mainly includes three parts of a volatile chamber, a super-high sensitivity photoionization source and a mass analyzer. The components to be measured generated in the volatile chamber pass through the four-fluorine tube and the sample inlet capillary in turn under the carrying of the air flow, and then enter the photoionization source region for ionization. The ion funnel for focusing a wide range of ions is arranged in the photoionization source, and the photoionization source with a larger light emission area is used to further improve the detection sensitivity. The focused ions are transmitted to the mass analyzer for detection. The device and method used by the application have a significant improvement in sensitivity, meet the detection requirements of trace difficult volatile organic pollutants, and have a very good effect on substances such as phthalate and polycyclic aromatic hydrocarbon.

[0046] The above description is only an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the present invention are included in the scope of protection of the present invention.

Claims

1. A device for real-time online analysis of non-volatile organic pollutants, characterized in that: The invention comprises a sample injection module, a vacuum ultraviolet lamp (2), an ionization source cavity (3), a repeller electrode (4), an ion funnel (7), a mass analyzer (8) and a vacuum pumping module, wherein the ionization source cavity (3) is provided with a sample injection port, a vacuum pumping port and an ion output port, the vacuum ultraviolet lamp (2), the repeller electrode (4) and the ion funnel (7) are sequentially arranged in the ionization source cavity (3) along the axis direction of the ion output port, and the ion funnel (7) is close to the ion output port, and the light emitted by the light source emitting end of the vacuum ultraviolet lamp (2) passes through the repeller electrode (4) and the ion funnel (7) in sequence. 7); the sampling module is arranged at the sampling port, and transports the sample to be tested into the ionization source cavity (3); the vacuum pumping module is arranged on the vacuum pumping port, and is used for vacuuming the ionization source cavity (3); the ion output port is externally connected to the mass analyzer (8); a DC voltage is applied to the repeller electrode (4), and a DC voltage and a radio frequency voltage are applied to the ion funnel (7); the sample is ionized under the action of the vacuum ultraviolet lamp (2), and the sample ions are focused and transmitted to the mass analyzer (8) under the action of the repeller electrode (4) and the ion funnel (7), so as to achieve final detection and analysis; The injection module comprises an injection capillary (1), a volatilization chamber (10) and a sample delivery tube (12), wherein an air inlet and an air outlet are respectively provided on both sides of the volatilization chamber (10), the air inlet is externally connected to a flow meter (9), and the flow meter (9) is used to control the flow rate of the carrier gas entering the volatilization chamber (10); the air outlet is tightly connected to one end of the sample delivery tube (12), and the other end of the sample delivery tube (12) is tightly connected to one end of the injection capillary (1) through a three-hole joint (13); the other end of the injection capillary (1) penetrates into the ionization source cavity (3) from the injection port and extends to the space between the repeller electrode (4) and the ion funnel (7); the sample to be tested (11) is placed in the volatilization chamber (10); The volatilization chamber (10), the sample delivery tube (12), the three-hole connector (13) and the injection capillary (1) are all wrapped by a heating device, and the temperature of the heating device can be adjusted between 0-200°C.

2. The device for real-time online analysis of low-volatile organic pollutants according to claim 1, characterized in that: The ion funnel (7) comprises a plurality of annular flat plate funnel electrodes which are arranged in parallel and at equal intervals and each have a circular through hole, and the aperture of the circular through hole of each annular flat plate funnel electrode decreases in sequence along the light emission direction of the vacuum ultraviolet lamp (2).

3. The device for real-time online analysis of low-volatile organic pollutants according to claim 2, characterized in that: The DC voltage applied to the repeller electrode (4) and each annular flat plate funnel electrode in the ion funnel (7) decreases in sequence along the direction of light emitted from the light source end of the vacuum ultraviolet lamp (2) to form a DC gradient electric field; A radio frequency voltage is applied to each annular flat funnel electrode in the ion funnel (7), and the radio frequency peak-to-peak amplitudes of any two adjacent annular flat funnel electrodes are equal and the phases are opposite.

4. The device for real-time online analysis of low-volatile organic pollutants according to claim 3, characterized in that: The gradient electric field of the DC gradient electric field is 2-20 V / cm; the radio frequency frequency of the radio frequency voltage is 0.5-5 MHz, and the radio frequency peak-to-peak value is 10-800 V; the number of the annular flat funnel electrodes is N, and N is an even number.

5. The device for real-time online analysis of low-volatile organic pollutants according to claim 2, characterized in that: The repelling electrode (4) is an annular flat plate structure with a circular through hole in the middle; the thickness of the repelling electrode (4) is 2-4 mm, and the diameter of the circular through hole in the middle is 4-10 mm; The thickness of each annular flat plate funnel electrode in the ion funnel (7) is 0.5-1 mm, and the diameter of the circular through hole in the middle thereof is 1-20 mm; The repeller electrode (4) and each of the annular flat plate funnel electrodes are made of conductive metal or a flat plate with a conductive metal layer plated on its surface.

6. The device for real-time online analysis of low-volatile organic pollutants according to claim 2, characterized in that: The vacuum ultraviolet lamp (2) is a low-pressure krypton lamp with a large light window diameter, and the photon emission diameter is 6-12 mm.

7. The device for real-time online analysis of low-volatile organic pollutants according to claim 1, characterized in that: The carrier gas flowing through the flow meter (9) is nitrogen or helium, the gas flow rate is 50-200 ml / min, and the carrier gas flow rate is greater than the injection volume of the injection capillary (1); The inner diameter of the sample delivery tube (12) is 3-6 mm, and the inner diameter of the injection capillary (1) is 100-250 μm.

8. The device for real-time online analysis of low-volatile organic pollutants according to claim 1, characterized in that: The vacuum pumping module comprises an air pressure valve (5) and a vacuum mechanical pump (6); the vacuum pumping port of the ionization source cavity (3) is connected to the air pressure valve (5) and the vacuum mechanical pump (6) in sequence from the inside to the outside; The air pressure in the ionization source cavity (3) is between 10-1000 Pa and is regulated by the air pressure valve (5) and the vacuum mechanical pump (6).

9. A method for real-time online analysis of low-volatile organic pollutants using the device as claimed in claim 7, characterized in that: The sample to be tested (11) is placed in a volatilization chamber (10), and the heating temperature is set. A carrier gas with a fixed flow rate is introduced into the volatilization chamber (10) through a flow meter (9). The carrier gas carries the volatile components of the sample to be tested (11) and passes through a sample delivery tube (12), a three-hole connector (13) and an injection capillary (1) in sequence and then enters the ionization source chamber (3); the low-content, non-volatile components are first efficiently ionized under the action of a vacuum ultraviolet lamp (2) with a large photon emission diameter, and then the sample ions are effectively focused under the action of a repeller electrode (4) and an ion funnel (7) and transmitted to a mass analyzer (8) for final detection and analysis.

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