Paper spray ionization online detection system and method for aerosol multiphase reaction kinetics

Abstract

The invention relates to an aerosol multiphase reaction kinetics-oriented paper spray ionization online detection system, which comprises a paper spray ionization assembly, an aerosol reactant and product channel and an online detection device, and is characterized in that the paper spray ionization assembly comprises an adjustable assembly, a clamping assembly and a paper spray substrate; the end, away from a clamping opening, of the clamping assembly is connected with the adjustable assembly, and the clamping opening end of the clamping assembly is connected with the paper spray substrate. The liquid conveying device is connected with the paper spray substrate; the clamping assembly is connected with the power supply; the paper spray substrate and the on-line detection device are on the same straight line, and the distance between the spray end of the paper spray substrate and the sample introduction end of the on-line detection device is D1; the paper spray substrate and the aerosol reactant and product channel are in the same vertical direction, and the distance between the spray end of the paper spray substrate and the outlet end of the aerosol reactant and product channel is D2.

Description

Technical Field

[0001] The invention belongs to the technical field of online detection of aerosol particle multiphase reaction kinetics, and in particular relates to a paper spray ionization online detection system and method for aerosol multiphase reaction kinetics. Background Art

[0002] Organic aerosol is an important component of atmospheric particulate matter and has a significant impact on air quality. Its formation and transformation process involves complex multiphase oxidation reactions, which will change the mass and chemical composition of organic aerosols, thereby affecting their environmental effects. Through the study of aerosol multiphase oxidation reactions, we can gain a deep understanding of the mechanism and kinetics of these reactions, providing a scientific basis for predicting and controlling air pollution. The experimental detection of the microscopic chemical structure of the products of aerosol multiphase oxidation reactions is the core part of the particle oxidation experiment, which aims to analyze the detailed information of the reactants and products, as well as the kinetic characteristics of this substance changing with time and temperature.

[0003] The experimental detection method of aerosol multiphase oxidation reaction products mostly uses mass spectrometry. Compared with other detection methods, mass spectrometry can provide detailed chemical structures of products and complex intermediates and their evolution details. Among them, online mass spectrometry has great advantages in rapid analysis and real-time reaction detection, making it possible to detect complex multiphase reaction systems in situ. Compared with the offline method of collecting reaction products and then performing information analysis, online mass spectrometry can detect the reaction process completely in real time, and thus conduct in-depth research on the reaction kinetics of multiphase oxidation reactions.

[0004] The key to achieving this goal through mass spectrometry is the efficient and stable ionization process of the reaction products. The current online mass spectrometry technologies mainly include electrospray ionization mass spectrometry, proton transfer reaction mass spectrometry, and atmospheric pressure chemical ionization mass spectrometry. These mass spectrometry technologies have their own advantages and disadvantages for real-time online analysis of chemical reaction products. For example, electrospray ionization (ESI) is the preferred ion generation mode in the mass analysis of many organic substances. The structural components of electrospray ionization mainly include high-voltage electrospray capillary, auxiliary nebulizer, desolvation device, and vacuum interface system. The high-voltage electrospray capillary is responsible for spraying the sample solution under the action of a high-voltage electric field to form charged droplets, and the auxiliary nebulizer promotes the atomization of droplets by providing strong shear force or ultrasonic action. The desolvation device uses heating or auxiliary gas to evaporate the solvent, so that the ions in the droplets are gradually exposed and converted into gas-phase ions. Finally, the vacuum interface system introduces these gas-phase ions into the mass spectrometer for further analysis to ensure the accuracy and sensitivity of the analysis. These components work together to achieve efficient conversion from sample solution to gas-phase ions, providing an important ion source for mass spectrometry analysis. However, due to the low concentrations in most environments (about 10 μg / m 3), the application of electrospray ionization (ESI) in aerosol particle analysis has always been limited. Aerosol mass spectrometers usually use analyte volatilization and then electronic ionization or chemical ionization, which may cause a considerable degree of analyte fragmentation. With the introduction of a series of new methods based on ESI, it is helpful to expand its application in particle phase product analysis. He et al. (Anal. Chem. 87 (2015) 6752-6760) proposed an electrostatic precipitation electrospray ionization (EP-ESI) method, which uses monopolar ionization to charge and pretreat aerosol particles. Electrostatic precipitation collects particles at the tip of a tungsten rod, and then flows liquid on the rod to perform ESI and mass analysis on the substances that make up the collected particles. In addition, electrospray extraction ionization (EESI, Science Bulletin, (2012) 1918-1927) technology is also an emerging ionization technology developed in recent years for direct mass spectrometry analysis of complex matrix samples. This technology can analyze samples of different forms such as liquids, aerosols, solid surfaces, and viscous samples. Under the action of a high-voltage electric field, the sample solution forms charged droplets; these droplets collide and extract with neutral droplets in the target sample to form charged droplets containing the target analytes; as the solvent evaporates and the droplets fission, the target analytes enter the mass spectrometer in the form of gas phase ions for detection and analysis.

[0005] According to the above background, the key to the study of aerosol multiphase oxidation reactions lies in the real-time online detection of complex products. At present, the main way to achieve this goal is mass spectrometry. The key to this technology is the efficient and stable ionization of complex products, and then the high-precision qualitative and quantitative analysis of the products based on the mass spectrometer. The ionization of complex products requires the use of an ion source device. For example, He et al. (Anal. Chem. 87 (2015) 6752-6760) proposed an electrostatic precipitation electrospray ionization (EP-ESI) method, which requires the aerosol particles to be pre-treated with a high voltage in advance, which may cause damage to the reaction system; in addition, the method requires at least two high-voltage power supply devices, resulting in the complexity of the entire device. Although the electrospray extraction ionization (EESI, Science Bulletin, (2012) 1918-1927) technology does not require pretreatment of aerosol particles, the technology requires a spray pressure of about 1.4MPa to be applied to the solvent. The main purpose of this is to ensure a stable spray gas flow and mass spectrometry signal, but this causes the complexity of the overall device. Summary of the invention

[0006] In view of the shortcomings in the prior art, the present invention provides a paper spray ionization online detection system and method for aerosol multiphase reaction kinetics, which are used to solve the problems in the prior art that it is impossible to realize real-time online detection of aerosol reaction products, resulting in an incomplete understanding of aerosol multiphase reaction kinetics; the accuracy is insufficient when detecting complex chemical components, and it is difficult to achieve high-precision characterization at the molecular level; the pretreatment steps are complicated, which damages the aerosol multiphase oxidation reaction products and accelerates possible secondary reactions, affecting the accuracy of the data; the equipment is highly complex, and the existing mass spectrometry ionization schemes are insufficient in structural complexity and operational flexibility, resulting in difficulty in equipment operation and high maintenance costs; the sensitivity is insufficient when detecting low-concentration aerosol particles, and the stability is poor in long-term continuous detection, etc.

[0007] The first aspect of the present invention provides a paper spray ionization online detection system for aerosol multiphase reaction kinetics, comprising a paper spray ionization component, an aerosol reactant and product channel and an online detection device, wherein the paper spray ionization component comprises an adjustable component, a clamping component and a paper spray matrix, wherein the end of the clamping component away from the clamp is connected to the adjustable component, and the clamping end of the clamping component is connected to the paper spray matrix; further comprising a liquid delivery device, wherein the liquid delivery device is connected to the paper spray matrix; the clamping component is connected to a power supply; the paper spray matrix and the online detection device are in the same straight line, and the distance between the spray end of the paper spray matrix and the injection end of the online detection device is D1; ​​the paper spray matrix and the aerosol reactant and product channel are in the same vertical direction, and the distance between the spray end of the paper spray matrix and the outlet end of the aerosol reactant and product channel is D2.

[0008] The second aspect of the present invention provides a paper spray ionization online detection method for aerosol multiphase reaction kinetics, comprising the following steps:

[0009] 1) adjusting the adjustable component, moving the position of the paper spray matrix so that it is in the same straight line as the injection end of the online detection device, starting the liquid delivery device to deliver the solvent to the paper spray matrix, and after the paper spray matrix is ​​moistened, starting and adjusting the voltage value of the power supply to generate spray at the spray end of the paper spray matrix, and after the spray is stable, fine-tuning the adjustable component again as needed to obtain a stable mass spectrometry background signal;

[0010] 2) After obtaining the stable mass spectrometry background signal described in step 1), the aerosol reaction product is transported through the aerosol reactant and product channel to mix with the spray described in step 1), and the neutral molecules therein are ionized into ions and then enter the online detection device for analysis and detection.

[0011] The third aspect of the present invention provides a component detection method for a paper spray ionization online detection system for aerosol multiphase reaction kinetics.

[0012] The detection objects are: aerosol reactants and their oxidation products;

[0013] The mass spectrometry conditions were as follows: ionization mode: paper spray ionization; sheath gas flow rate: 1-2 Arb; auxiliary gas flow rate: 3-5 Arb; sweep gas flow rate: 3-5 Arb; ion transfer tube temperature: 300-400°C; scanning mass range: 50-1000 Da; mass resolution: 500000 at 200 Da.

[0014] The present invention has the following beneficial effects:

[0015] (1) High temporal resolution: Real-time online detection of aerosol multiphase oxidation reaction products is achieved, providing a comprehensive understanding of the reaction kinetics.

[0016] (2) High detection accuracy: By coupling paper spray ionization technology and ultra-high resolution mass spectrometry technology, the detection accuracy of complex chemical components in aerosols is significantly improved, achieving high-precision characterization at the molecular level.

[0017] (3) Simplified sample preparation: No heating or other complicated pretreatment steps are required, which reduces damage to the products of aerosol multiphase oxidation reactions, avoids the acceleration of secondary reactions, and ensures data accuracy.

[0018] (4) Simple structure and easy operation: The optimized design makes the device simple in structure and easy to operate, suitable for a variety of experimental environments, and highly feasible. Through the optimized design, the flexibility and convenience of operation are improved, ensuring the stable operation of the device in long-term and continuous online detection.

[0019] (5) High sensitivity and stability: The detection sensitivity of low-concentration aerosol particles is improved and high stability is maintained in long-term continuous detection; it can accurately reveal the kinetic process of aerosol multiphase oxidation reactions, providing strong technical support for reaction kinetics research and comprehensive analysis of multiphase reaction systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall device structure of the present invention.

[0021] Figure 2 Graph showing the variation of background signal intensity with different voltages in Example 2.

[0022] Figure 3 This is a graph showing the change in background signal intensity with different solvent flow rates in Example 3.

[0023] Figure 4This is a graph showing the variation of background signal intensity with purge rate in Example 4.

[0024] Figure 5 This is the particle diameter distribution diagram in Example 5.

[0025] Figure 6 This is a graph showing the change in mass spectrometry signal intensity with the concentration of oleic acid aerosol particles in Example 6.

[0026] Figure 7 Figure 7 is the mass spectrum of the multiphase oxidation reaction of oleic acid aerosol in Example 7, Figure (a) is the background signal mass spectrum; Figure (b) is the mass spectrum of oleic acid aerosol without ozone; Figure (c) is the mass spectrum of oleic acid and oxidation products after ozone is introduced.

[0027] Figure 8 The mass spectra of the oxidation products m / z 157.09 and m / z 157.02 in Example 8 are shown.

[0028] Fig. 9 The figure is a reaction kinetic diagram of oleic acid aerosol particles (m / z 281) and their main oxidation products (m / z 157, m / z 171, m / z 187) in Example 9 as the amount of ozone exposure changes.

[0029] Fig.10 This is a graph showing the relationship between the effective absorption coefficient and the particle mass concentration in Example 10.

[0030] Component number description

[0031] 1 Paper spray ionization assembly

[0032] 11 Adjustable components

[0033] 12 Clamping assembly

[0034] 121 Voltage

[0035] 13 Paper spray substrate

[0036] 14 Liquid delivery device

[0037] 141 Pipe

[0038] 2 Aerosol reactant and product channels

[0039] 3 Online detection device DETAILED DESCRIPTION

[0040] Hereinafter, the embodiments of the paper spray ionization online detection system and method for aerosol multiphase reaction kinetics disclosed specifically will be described in detail.

[0041] The present invention applies the paper spray ionization mass spectrometry analysis scheme to the real-time online detection of aerosol multiphase oxidation reactants and products through structural optimization. The structure is simple, no heating device is required, possible secondary reactions will not be accelerated, and no complicated sample preparation process is required, thereby realizing the ionization and detection of aerosol multiphase oxidation reaction products. When coupled with a high-resolution mass spectrometer, the kinetic information of reactants and products can be obtained in real time. On this basis, the present invention is completed.

[0042] See also Figures 1 to 10 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings in this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0043] like Figure 1 In a first aspect, the present invention provides a paper spray ionization online detection system for aerosol multiphase reaction kinetics, comprising a paper spray ionization component 1, an aerosol reactant and product channel 2 and an online detection device 3, wherein the paper spray ionization component 1 comprises an adjustable component 11, a clamping component 12 and a paper spray matrix 13, wherein the end of the clamping component 12 away from the clamp is connected to the adjustable component 11, and the clamping end of the clamping component 12 is connected to the paper spray matrix 13; further comprising a liquid delivery device 14, wherein the liquid delivery device 14 is connected to the paper spray matrix 13; the clamping component 12 is connected to a power supply; the paper spray matrix 13 and the online detection device 3 are in the same straight line, and the distance between the spray end of the paper spray matrix 13 and the injection end of the online detection device 3 is D1; ​​the paper spray matrix 13 and the aerosol reactant and product channel 2 are in the same vertical direction, and the distance between the spray end of the paper spray matrix 13 and the outlet end of the aerosol reaction product and channel 2 is D2.

[0044] In the paper spray ionization online detection system for aerosol multiphase reaction kinetics provided by the present invention, the adjustable component 11 is a three-dimensional adjustable platform (brand: OMTOOLS, model: SPYD80L). The three-dimensional adjustable platform can adjust the height of the paper spray matrix 13 in the Z direction. After the height is determined, the platform can accurately adjust the paper spray matrix 13 to move and position accurately in the X and Y directions, and also play a role in providing stable support, effectively preventing the paper spray matrix 13 from displacement or vibration during the experiment, thereby improving the repeatability and comparability of the experimental results.

[0045] In the paper spray ionization online detection system for aerosol multiphase reaction kinetics provided by the present invention, the liquid delivery device 14 is a syringe pump (brand: Chemyx, model: Fusion 101A). The liquid delivery device 14 delivers solvent to the paper spray matrix 13 through a pipeline 141 to wet the paper spray matrix 13 and evenly distribute the solvent on the paper spray matrix 13.

[0046] In the paper spray ionization online detection system for aerosol multiphase reaction kinetics provided by the present invention, one end of the pipeline 141 is connected to the output end of the liquid delivery device 14, and the other end is connected to the central part of the paper spray matrix.

[0047] In the paper spray ionization online detection system for aerosol multiphase reaction kinetics provided by the present invention, the paper spray matrix 13 is a paper triangle. The paper of the paper triangle is Whatman 3MM grade cellulose chromatography paper, and the paper thickness is 0.33-0.35mm, which can be selected as 0.33-0.34mm or 0.34-0.35mm. The paper triangle is cut into isosceles triangles using a laser cutting machine, and the laser frequency is 20kHz. The base length of the isosceles triangle is 7-9mm, which can be selected as 7-8mm or 8-9mm; the height is 9-11mm, which can be selected as 9-10mm or 10-11mm.

[0048] In the paper spray ionization online detection system for aerosol multiphase reaction kinetics provided by the present invention, the clamping component 12 is a stainless steel flat alligator clip. The clamping component 12 is connected to a high-voltage power supply (brand: SRS, model: PS300), and the voltage value of the high-voltage power supply is 3000-5000V, which can be selected as 3000-4000V or 4000-5000V. The high-voltage power supply applies voltage to the spray end of the paper spray matrix 13, so that the solution on the paper spray matrix 13 forms charged droplets under the action of the electric field and gradually evaporates. During the process, the solvent molecules are removed, leaving charged analyte molecules, which are the ions required for mass spectrometry detection. By regulating the power supply voltage, on the one hand, the formation process of charged droplets can be optimized, the ionization efficiency can be improved, and the intensity and stability of the mass spectrometry signal can be enhanced; on the other hand, appropriate voltage regulation can ensure the stability of the spray process, avoid excessive or too small droplets, and ensure the continuity and consistency of the ionization process. In addition, by accurately regulating the voltage, background noise can also be reduced, the signal-to-noise ratio can be improved, and the detection sensitivity and accuracy can be improved.

[0049] In the paper spray ionization online detection system for aerosol multiphase reaction kinetics provided by the present invention, the distance D1 between the spray end of the paper spray matrix 13 and the injection end of the online detection device 3 is 15-20mm, which can be selected as 15-16mm, 16-17mm, 17-18mm, 18-19mm or 19-20mm, etc. Within this range, the aerosol particles can be fully ionized and enter the mass spectrometer, which can ensure the signal intensity of the mass spectrometer. If D1 is too large, the number of ions entering the mass spectrometer is small, which leads to a weak mass spectrometer signal, which is not conducive to the online detection of the sample; if D1 is too small, it may cause insufficient ionization of aerosol particles and even block the ion transmission pipeline of the mass spectrometer. The present invention has been verified by experiments that when D1 is in the above range, the mass spectrometer signal intensity and stability can be guaranteed to the greatest extent.

[0050] In the paper spray ionization online detection system for aerosol multiphase reaction kinetics provided by the present invention, the distance D2 between the spray end of the paper spray matrix 13 and the outlet end of the aerosol reactant and product channel 2 is 8-10mm, which can be optionally 8-9mm or 9-10mm. D2 is in this range to ensure the intensity and stability of the mass spectrometry signal. If D2 is too large, the aerosol particles may not be fully mixed with the charged spray, resulting in insufficient sample ionization and other problems; if D2 is too small, it may cause excessive purge force, resulting in changes in the spray shape, thereby reducing the stability of the detection.

[0051] In the paper spray ionization online detection system for aerosol multiphase reaction kinetics provided by the present invention, the online detection device 3 is an ultra-high resolution mass spectrometer (brand: Thermo Fisher Scientific, model: OrbitrapFusion).

[0052] The second aspect of the present invention provides a paper spray ionization online detection method for aerosol multiphase reaction kinetics, comprising the following steps:

[0053] 1) adjusting the adjustable component, moving the position of the paper spray matrix so that it is in the same straight line as the injection end of the online detection device, starting the liquid delivery device to deliver the solvent to the paper spray matrix, and after the paper spray matrix is ​​moistened, starting and adjusting the voltage value of the power supply to generate spray at the spray end of the paper spray matrix, and after the spray is stable, fine-tuning the adjustable component again as needed to obtain a stable mass spectrometry background signal;

[0054] 2) After obtaining the stable mass spectrometry background signal described in step 1), the aerosol reaction product is transported through the aerosol reactant and product channel to mix with the spray described in step 1), and the neutral molecules therein are ionized into ions and then enter the online detection device for analysis and detection.

[0055] In step 1) of the present invention, the solvent is a mixed solvent of a mixed solvent of methanol and chloroform. In the mixed solvent of methanol and chloroform, the volume ratio of methanol to chloroform is (1-3):1, which can be optionally (1-2):1 or (2-3):1. In the paper spray ionization process, the properties of the solvent have an important influence on the ionization effect. Methanol has a low surface tension and good solubility, which helps the dissolution and ionization of the analyte in the solution; while chloroform has different polarity and solubility characteristics, which can reduce the corona discharge at the tip of the paper. The mixture of the two can combine the advantages of both to form a stable electrospray, more effectively dissolve the compounds in the sample and migrate to the tip of the paper, thereby improving the ionization efficiency and the sensitivity of mass spectrometry. In the present invention, the ionization effect is best when the solvent is in this ratio range.

[0056] In step 1) of the present invention, the flow rate at which the liquid delivery device delivers the solvent to the paper spray matrix is ​​10-15 μL / min, which can be 10-12 μL / min or 12-15 μL / min. Different flow rates will lead to different spray patterns, such as single cone spray, multi-jet and edge spray patterns. By controlling the flow rate within this range, the spray pattern can be optimized, the fluctuation of the charge density can be reduced, and a stable spray pattern can be ensured, thereby improving the ionization efficiency.

[0057] In step 2) of the present invention, one or more of nitrogen and / or aerosol particles and their oxidation products are passed through the aerosol reactant and product channels to prevent the aerosol reaction products from being oxidized by air, thereby protecting the integrity of the sample. The nitrogen purge rate is 350-450 mL / min, which can be optionally 350-400 mL / min or 400-450 mL / min. The nitrogen purge rate is controlled within this range to optimize the transmission efficiency of the aerosol reaction products and ensure that the aerosol reaction products reach the paper spray matrix 13 uniformly. In addition, controlling the nitrogen purge rate can also help maintain a stable spray pattern and ensure the stability and consistency of the ionization process.

[0058] A third aspect of the present invention provides a component detection method based on a paper spray ionization online detection system for aerosol multiphase reaction kinetics.

[0059] In the present invention, the detection objects are: aerosol reactants and their oxidation products.

[0060] In the present invention, the mass spectrometry conditions are: ionization mode: paper spray ionization; sheath gas flow rate: 1-2Arb, which can be selected as 1-1.5Arb or 1.5-2Arb; auxiliary gas flow rate: 3-5Arb, which can be selected as 3-4Arb or 4-5Arb; purge gas flow rate: 3-5Arb, which can be selected as 3-4Arb or 4-5Arb; ion transfer tube temperature: 300-400°C, which can be selected as 300-350°C or 350-400°C; scanning mass range: 115-1000Da, which can be selected as 115-300Da, 300-500Da, 500-700Da, 700-900Da or 900-1000Da, etc.; mass resolution: 500000 at 200Da.

[0061] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is described in detail below in conjunction with embodiments and drawings.

[0062] In the following examples, unless otherwise specified, all reaction raw materials are commercially available products.

[0063] Unless otherwise specified, the purity of each product in each embodiment of the present invention exceeds 98%.

[0064] Example 1

[0065] The use process of the paper spray ionization online detection system for aerosol multiphase reaction kinetics

[0066] like Figure 1As shown, at the beginning of the experiment, by adjusting the three-dimensional adjustable platform, the paper triangle and the online detection device 3 are controlled to be in the same straight line, and the distance between the tip of the paper triangle and the injection end of the online detection device 3 is 15-20 mm; the paper triangle and the aerosol reactant and product channel 2 are in the same vertical direction, and the distance between the tip of the paper triangle and the outlet end of the aerosol reactant and product channel 2 is 8-10 mm. Start the injection pump to deliver a mixed solvent of methanol and chloroform to the paper triangle through the pipeline 141, and the volume ratio of methanol and chloroform is (1-3): 1. After the solvent wets the paper triangle, start and adjust the voltage value of the high-voltage power supply, the voltage range is 3000-5000V, until the tip of the paper triangle produces spray. After the spray is stably output, finely adjust and fix the position of the paper triangle to obtain a stable mass spectrum background signal, and the aerosol reaction product is mixed with the spray through the aerosol reactant and product channel 2, and the neutral molecules are ionized into ions. Finally, these ions are introduced into the ultra-high resolution mass spectrometer for analysis and detection.

[0067] Example 2

[0068] Background signal strength changes with different voltages

[0069] The present invention is verified by experiments ( Figure 2 ), and found that the higher the voltage applied to the paper triangle, the stronger the mass spectrometry signal. When the voltage reached about 4900 volts, the mass spectrometry signal value was the strongest, but the stability was poor. When the voltage reached about 4400 volts, the mass spectrometry signal could take into account both intensity and stability. Figure 2 The error bars in the figure are calculated as follows: for each specific voltage, the background signal mass spectrum value with a duration of about 30 seconds is selected and its relative error is calculated.

[0070] Example 3

[0071] Background signal intensity changes with different solvent flow rates

[0072] The present invention is verified by experiments ( Figure 3 ), it was found that when the solvent flow rate was higher, the mass spectrometry signal intensity was stronger; however, when the solvent flow rate exceeded 20 μL / min, the mass spectrometry signal intensity decreased and the stability decreased. When the solvent flow rate was 10 to 15 μL / min, the mass spectrometry signal value could take into account both intensity and stability, which was the optimal choice. Figure 3 The error bars in the figure are calculated as follows: for each specific solvent flow rate, the background signal mass spectrum value with a duration of about 30 seconds is selected and its relative error is calculated.

[0073] Example 4

[0074] Background signal intensity changes with purge rate

[0075] The purge rate refers to the nitrogen or product injection rate in the pipeline 141. The present invention is verified by experiments ( Figure 4 ), and found that when the nitrogen purge rate was 400 mL / min, the mass spectrometry signal value could take into account both intensity and stability, which was the optimal choice. Figure 4 The error bars in are calculated as follows: for each specific purge rate, the background signal mass spectrum value with a duration of about 30 seconds is selected and its relative error is calculated.

[0076] Example 5

[0077] Particle diameter distribution

[0078] The aerosol particles used in the present invention are measured by a scanning mobility particle size spectrometer (SMPS, TSI 3080L DMA and 3776CPC, USA) to obtain the particle mass concentration and particle size distribution. Figure 5 shown.

[0079] Example 6

[0080] Changes in mass spectrometry signal intensity with oleic acid aerosol particle concentration

[0081] Figure 6 This is a graph showing the change in mass spectrometry signal intensity with the concentration of oleic acid aerosol particles. It can be seen that the mass spectrometry signal intensity shows a linear response with the increase in the mass concentration of oleic acid particles, and the response is good.

[0082] Example 7

[0083] Mass spectrum of heterogeneous oxidation reaction of oleic acid aerosol

[0084] A set of mass spectra of oleic acid aerosol multiphase oxidation reaction Figure 7 As shown. Figure (a) is a background signal mass spectrum when oleic acid aerosol and ozone are not introduced. The background signals of the present invention mainly have mass numbers m / z 59.98 and m / z 61.99. Figure (b) shows the oleic acid signal (mass number m / z 281) detected by the present invention after only oleic acid aerosol is introduced. Figure (c) shows the signal of oleic acid and products detected by the present invention after oleic acid aerosol reacts with ozone. The predecessor J. Zahardis (Atmos. Environ. 40 (2006) 1661-1670) used photoelectron resonance capture ionization mass spectrometry to detect the products of the reaction of oleic acid and ozone, but failed to explore the reaction kinetics. The present invention not only detects the key products of the reaction of oleic acid and ozone (m / z 157, m / z 171, m / z 187), but also studies the reaction kinetics of oleic acid and products, which is one of the important advantages of the present invention.

[0085] Example 8

[0086] Mass spectra of m / z 157.09 and m / z 157.02

[0087] The present invention couples paper spray ionization with an ultra-high resolution mass spectrometer, and can distinguish species with very close mass numbers. Figure 8 The mass spectra of two species at m / z 157.09 and m / z 157.02 are shown.

[0088] Example 9

[0089] Reaction kinetics of oleic acid aerosol particles (m / z 281) and its main oxidation products (m / z 157, m / z 171, m / z 187) with ozone exposure

[0090] Fig. 9 Figure 2 shows the reaction kinetics of oleic acid aerosol particles (m / z 281) and its main oxidation products (m / z 157, m / z 171, m / z 187) as a function of ozone exposure. In this figure, ozone exposure is calculated by multiplying ozone concentration by reaction time (37 seconds).

[0091] Example 10

[0092] Relationship between effective absorption coefficient and particle mass concentration

[0093] In order to quantitatively determine the heterogeneous reaction rate of oleic acid aerosol particles with ozone, the decay rate (expressed as k) and the effective absorption coefficient (expressed as γ) of oleic acid particles were derived from equations E1 and E2 according to the method of Smith et al. (Aerosol Sci. Technol. 2023, 58 (4), 356-373). By monitoring the loss of particles during ozone exposure, that is, the ozone concentration reaction time, k is determined by fitting the decay data (that is, the ratio of the concentration of oleic acid aerosol particles to the initial concentration) to an exponential function (E1). γ was calculated using equation E2, which quantifies the heterogeneous reaction rate of oleic acid aerosol particles with ozone. In the equation, D is the aerosol particle size, ρ0 is the reactant density, N A is Avogadro's constant, c is the average velocity of ozone gas molecules, and M is the molar mass of the reactant molecules.

[0094] [particles] / [particles]0=exp(-k×ozone concentration×reaction time)(E1)

[0095]

[0096] Fig.10is the relationship between the effective absorption coefficient of oleic acid aerosol particles and the particle mass concentration. The effective absorption coefficient corresponding to the mass concentration of aerosol particles of the present invention is represented by a red dot. Other data are from literature (Anal.Chem.85(2013)2087-2095, J.Phys.Chem.A 118(2014)9471-9481, Phys.Chem.Chem.Phys.11(2009)7951-7962, J.Phys.Chem.A 109(2005)10910-10919, Faraday Discuss.130(2005)469-490). It can be seen that the quantitative method of the present invention for the multiphase oxidation reaction rate of oleic acid aerosol is reasonable.

[0097] In combination with Example 1, Example 8, Example 9 and Example 10, the voltage applied to the paper triangle of the present invention reaches about 4400 volts; the flow rate of delivering the solvent to the paper triangle is 10 to 15 μL / min; when the nitrogen purge rate in the aerosol reactant and product channels is 400 mL / min; the mass spectrometry signal can take into account both intensity and stability.

[0098] In combination with Example 4 and Example 5, the mass spectrometry signal intensity of the present invention shows a linear response with the increase of the mass concentration of oleic acid particles, and the response is good.

[0099] In combination with Example 1, Example 2 and Example 3, the present invention applies the paper spray ionization mass spectrometry analysis scheme to the real-time online detection of aerosol multiphase oxidation reaction products, not only detecting the key products (m / z157, m / z171, m / z 187) of the reaction between oleic acid and ozone, but also studying the reaction kinetics of oleic acid and products, and realizing the ionization and non-destructive detection of aerosol multiphase oxidation reaction products. In addition, the present invention couples paper spray ionization with an ultra-high resolution mass spectrometer, which can distinguish species with very close mass numbers, such as being able to distinguish m / z 157.09 and m / z 157.02. This paper spray ionization coupled ultra-high resolution mass spectrometry technology is the first to be applied to the qualitative and reaction kinetics research of aerosol particles, broadening the application scope of paper spray ionization combined with ultra-high resolution mass spectrometry.

[0100] In combination with Example 6 and Example 7, from the reaction kinetics of oleic acid aerosol particles (m / z 281) and its main oxidation products (m / z 157, m / z 171, m / z 187) as the amount of ozone exposure changes and the relationship between the effective absorption coefficient and the particle mass concentration, it can be seen that the quantitative method of the oleic acid oxidation reaction of the present invention is reasonable.

[0101] The above-mentioned embodiments are preferred examples of the present invention and are not intended to limit the protection scope of the present invention.

[0102] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the paper spray ionization online detection system and method for aerosol multiphase reaction kinetics of the present invention, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0103] The above embodiments are preferred cases of the present invention and are not intended to limit the protection scope of the present invention. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the present invention.

[0104] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A paper spray ionization online detection system for aerosol multiphase reaction kinetics, characterized in that: The invention comprises a paper spray ionization component (1), an aerosol reactant and product channel (2) and an online detection device (3), wherein the paper spray ionization component (1) comprises an adjustable component (11), a clamping component (12) and a paper spray matrix (13), wherein an end of the clamping component (12) away from the clamping opening is connected to the adjustable component (11), and a clamping end of the clamping component (12) is connected to the paper spray matrix (13); and further comprises a liquid conveying device (14), wherein the liquid conveying device (14) is connected to the paper spray matrix. (13) is connected; the clamping assembly (12) is connected to a power source; the paper spray matrix (13) and the online detection device (3) are in the same straight line, and the distance between the spray end of the paper spray matrix (13) and the injection end of the online detection device (3) is D1; ​​the paper spray matrix (13) and the aerosol reactant and product channel (2) are in the same vertical direction, and the distance between the spray end of the paper spray matrix (13) and the outlet end of the aerosol reactant and product channel (2) is D2.

2. The paper spray ionization online detection system for aerosol multiphase reaction kinetics according to claim 1, characterized in that: Includes any one or more of the following features: A1) the adjustable component (11) is a three-dimensionally adjustable platform; A2) the clamping assembly (12) is an alligator clip; A3) the liquid delivery device (14) is a syringe pump; A4) The online detection device (3) is an ultra-high resolution mass spectrometer.

3. The paper spray ionization online detection system for aerosol multiphase reaction kinetics according to claim 1, characterized in that: It also comprises a pipeline (141), one end of which is connected to the output end of the liquid conveying device (14), and the other end of which is connected to the central part of the paper spray matrix (13).

4. The paper spray ionization online detection system for aerosol multiphase reaction kinetics according to claim 1, characterized in that: The paper spray substrate (13) is a paper triangle.

5. The paper spray ionization online detection system for aerosol multiphase reaction kinetics according to claim 4, characterized in that: Also includes any one or more of the following features: B1) The paper of the paper triangle is Whatman 3MM grade cellulose chromatography paper; B2) The paper triangle is an isosceles triangle with a base length of 7 to 9 mm and a height of 9 to 11 mm.

6. The paper spray ionization online detection system for aerosol multiphase reaction kinetics according to claim 1, characterized in that: Includes any one or more of the following features: C1) D1 is 15 to 20 mm; C2) D2 is 8 to 10 mm.

7. A paper spray ionization online detection method for aerosol multiphase reaction kinetics, using the paper spray ionization online detection system for aerosol multiphase reaction kinetics as claimed in any one of claims 1 to 6, characterized in that: The steps include: 1) adjusting the adjustable component, moving the position of the paper spray matrix so that it is in the same straight line as the injection end of the online detection device, starting the liquid delivery device to deliver the solvent to the paper spray matrix, and after the paper spray matrix is ​​moistened, starting and adjusting the voltage value of the power supply to generate spray at the spray end of the paper spray matrix, and after the spray is stable, fine-tuning the adjustable component again as needed to obtain a stable mass spectrometry background signal; 2) After obtaining the stable mass spectrometry background signal described in step 1), the aerosol reactants and products are transported through the aerosol reactant and product channels to mix with the spray described in step 1), and the neutral molecules therein are ionized into ions and then enter the online detection device for analysis and detection.

8. The paper spray ionization online detection method for aerosol multiphase reaction kinetics according to claim 7, characterized in that: Includes any one or more of the following features: D1) the solvent in step 1) is a mixed solvent of methanol and chloroform; D2) the flow rate of the delivery solvent in step 1) is 10-15 μL / min; D3) The voltage value of the power supply in step 1) is 3000-5000V; D4) Nitrogen and / or aerosol reactant particles and their oxidation products are passed through the aerosol reactant and product channels described in step 2).

9. The paper spray ionization online detection method for aerosol multiphase reaction kinetics according to claim 8, characterized in that: Also includes any one or more of the following features: D11) In the mixed solvent of methanol and chloroform, the volume ratio of methanol to chloroform is (1-3):1; D41) The nitrogen purge rate is 350-450 mL / min.

10. A component detection method based on a paper spray ionization online detection system for aerosol multiphase reaction kinetics, using the paper spray ionization online detection system for aerosol multiphase reaction kinetics as described in any one of claims 1-6, and performing ultra-high resolution mass spectrometry detection according to the detection method described in any one of claims 7-9.

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