Mass spectrometry instrument and mass spectrometry method

Abstract

The invention discloses a mass spectrometry instrument and a single nanoparticle composition mass spectrometry method, which are characterized in that after nano aerosol particles with the particle size of less than 100nm are coagulated and increased, the size gt of the nano aerosol particles is increased; in order to avoid the problems of energy absorption, ionization efficiency reduction, spectrogram background increase and the like caused by the liquid layer in a laser ionization area, a laser preheating vaporization module with high time response is designed before the liquid layer enters the ionization area so as to realize rapid heating vaporization treatment of a condensing agent on the surface of a particle. The laser preheating vaporization module can thoroughly evaporate condensate, so that the ionization efficiency of the inner core is improved; the laser preheating vaporization module can effectively reduce fragment ions of organic aerosol, and organic and inorganic nanoparticles and the like can be analyzed through spectrogram treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of single nanoparticle mass spectrometry, in particular to a mass spectrometry instrument and a method for analyzing the composition of single nanoparticle mass spectrometry. BACKGROUND

[0002] Aerosol particles play an important role in environmental pollution, human health and climate change, and their chemical composition directly affects the toxicity, optical properties and interaction with cloud condensation nuclei of the particles. Therefore, accurate and real-time analysis of the composition of aerosol particles is of great significance for environmental monitoring, atmospheric chemistry research and climate modeling.

[0003] Single Particle Aerosol Mass Spectrometer (SPAMS) is an instrument system that can realize real-time online component analysis of single aerosol particles. It combines air dynamic particle size measurement and laser ionization time-of-flight mass spectrometry (TOF-MS) technology, which can simultaneously obtain particle size information and chemical composition on a sub-second time scale. Commonly detected components include organic carbon (OC), elemental carbon (EC), heavy metal elements, inorganic salts (such as sulfate, nitrate, ammonium salt), and organic fragment ions, etc. This technology is widely used in environmental pollution source analysis, atmospheric particle transport mechanism research, health impact assessment and other fields.

[0004] The basic detection principle of SPAMS is based on the process of "double-beam laser sizing + laser gasification ionization + dual-pole time-of-flight mass spectrometry analysis": (1) Particle focusing and sizing: aerosol particles are first focused by an air dynamic lens system to form a collimated beam, and then pass through two fixed-interval laser beams. When the particles pass through the laser, light scattering signals will be generated, and the system calculates the aerodynamic particle size by the time difference between the two scattering signals and predicts the time when the particles reach the ionization area. (2) Laser ionization: when the particles reach the center position of the ionization area, a high-energy pulsed laser (usually 266 nm, Nd:YAG fourth harmonic) is used to irradiate the particles to rapidly vaporize and ionize them. The laser energy can be adjusted to meet the ionization needs of different types of particles, such as lower energy for organic matter and higher energy for metal or mineral particles. (3) Mass spectrometry analysis: the generated positive and negative ions are accelerated by an electric field and then enter the dual-pole time-of-flight mass spectrometer (TOF-MS) for mass-to-charge ratio separation, realizing the simultaneous acquisition of positive ion and negative ion spectra. Through precise time stamp matching technology, the particle size and component spectrum are matched one by one, thus completing the qualitative analysis of single particles. Figure One

[0005] ​However, the particle detection method based on light scattering of the system has physical limitations when facing sub-100 nm particles. According to Mie scattering theory or Rayleigh scattering, the light scattering intensity of the particles is roughly proportional to the sixth power of the particle size, so when the particle size is less than about 100 nm, the scattering signal will be significantly weakened, making it difficult for the system to accurately trigger the ionization process, thereby greatly reducing the detection efficiency.

[0006] Condensational Growth technology increases the size of ultrafine particles by introducing supersaturated water vapor or other low-volatility condensates into the aerosol, causing condensation growth on the surface of the ultrafine particles, thereby increasing their particle size to the range that can be detected by light scattering (usually greater than 300 nm). This technology has been widely used in condensation particle counters (CPC) and has also been applied to the pre-mass spectrometry particle size increase to improve the single-particle detection efficiency of nanoparticles.

[0007] Therefore, the combination of condensation growth technology and single-particle mass spectrometry technology is expected to achieve efficient component analysis of nanoscale aerosol particles, further expanding the application potential of single-particle mass spectrometry technology in the fields of environmental nanoparticle pollution, health exposure assessment, and new particle formation research.

[0008] The existing SPAMS system has low detection efficiency for sub-100 nm particles, mainly because the triggering system relies on light scattering signals, and the scattering signal of nanoparticles is weak; after condensation growth, there is a condensate on the surface of the particles, and laser ionization cannot achieve the detection and analysis of the sub-100 nm aerosol core. Therefore, we propose a single nanoparticle composition mass spectrometry method. SUMMARY

[0009] The purpose of the present application is to solve the problems mentioned in the background art, and the present application provides a single nanoparticle composition mass spectrometry method.

[0010] The present application specifically adopts the following technical solutions to achieve the above-mentioned purposes: A mass spectrometry instrument, comprising: A condensation growth module for increasing the size of ultrafine particles that cannot be detected by optical triggering to an optically measurable range; A sample introduction module for introducing a sample; A sizing module, after the particles pass through the focused beam, enter the region of the double-beam laser sizing system, the two continuous lasers have a fixed spacing in space, and when the particles pass through, they will scatter the two lasers in turn, and the time difference of the scattering peaks is calculated by the light detection system to obtain the aerodynamic diameter. This signal is also used as a reference for subsequent laser triggering and pre-heating timing; The laser preheating vaporization module is used for realizing non-contact and rapid vaporization treatment on the surface of particles, adopts a laser as a light source, is matched and selected according to the absorption characteristics of the condensing agent in the infrared wave band, so as to realize high-efficiency light-heat conversion, and the condensing agent adsorbed on the surface of the particles is completely evaporated in several microseconds by the laser, so that the core of the particles is exposed to an ionization area and enters a subsequent ionization process; The high-energy laser ionization module is used for realizing rapid ablation ionization of the sample to form positive and negative ions for subsequent mass spectrum analysis. The bipolar time-of-flight mass spectrum module is used for realizing element-level analysis and organic fragment analysis by synchronously collecting positive and negative ion spectrum diagrams through high-resolution mass spectrum and spectrum processing.

[0011] Further, the condensation growth module comprises: The saturator is used for evaporating the liquid condensing agent into vapor with a stable concentration, and forming a highly saturated or supersaturated gas environment after being mixed with the carrier gas, so as to meet the needs of subsequent particle condensation growth; The condenser is a pipeline made of heat insulation or temperature control material, which is used for inducing the vapor to condense on the surface of the particles through the temperature gradient of the inner wall, and for growing the particles by controlling the condensation length and temperature difference; a cold trap or a drying section is arranged at the outlet end to capture the excess vapor and prevent a large amount of uncondensed vapor from leaking to the downstream system; the surface of the grown particles is coated with a liquid layer of the condensing agent with a thickness of tens to hundreds of nanometers, which is beneficial to subsequent diameter measurement.

[0012] Further, the sample inlet module comprises a gas flow balance interface, an erosion device, a critical orifice and an aerodynamic lens, the gas flow balance interface is used for stabilizing the pressure and flow rate in the sample inlet path to ensure that the aerodynamic lens can normally work under constant flow rate; the erosion device is composed of porous activated carbon or zeolite and is arranged before the critical orifice, and is used for adsorbing and removing the organic condensing agent vapor which is not completely condensed, so as to prevent the organic condensing agent vapor from entering the downstream ionization and mass spectrum analysis system to cause background fluctuation interference; the critical orifice has a pore diameter of 0.1mm-0.2mm and is arranged in the main sample inlet path, and is used for limiting the total sample flow rate, so that the system can work under stable and near-critical flow conditions to avoid the influence of flow rate fluctuation on the measurement accuracy; the aerodynamic lens is composed of single lenses with different pore diameters in multiple stages, has a front-end vacuum degree of 200-300Pa and a focusing range of 100nm-5μm, and is used for collimating and focusing the grown aerosol particles to form a stable narrow beam particle flow, so as to accurately capture the particle flow by the laser diameter measurement system and for subsequent laser ionization mass spectrum analysis.

[0013] Further, the scattering signal generated by the diameter measurement module is collected by a high-sensitivity photomultiplier tube or avalanche photodiode, and the speed and the data of the increased particle diameter are output in real time by cooperating with a time sequence card.

[0014] Further, the laser in the laser preheating vaporization module is selected from one of a CO2 laser, a near-infrared laser, a ceramic heating element and a microwave source.

[0015] Further, the high-energy laser ionization module adopts a pulse laser as a main energy source, and the typical laser output energy is 0.1-10 mJ / pulse, so as to adapt to the ionization requirements of particles of different components and sizes, and the pulse duration is set in the range of 3-50 ns.

[0016] Further, the high-energy laser ionization module supports adjustable laser energy to adapt to the excitation requirements of different types of particles, the triggering time of the ionization laser is uniformly managed by a high-precision time sequence control card, and the time delay difference between the ionization laser and the preheating laser excitation signal is controlled in the range of 0-10 μs, so as to ensure that the particles are ionized after completing the condensate vaporization, and ideal energy coupling efficiency and ionization effect are obtained.

[0017] Further, the time sequence control is also included, and an FPGA or a high-performance MCU is used as a core control unit to realize timing from the diameter measurement signal, trigger the preheating laser before the particles arrive, and accurately trigger the preheating vaporization laser and the ionization laser.

[0018] Further, the data processing module is also included to coordinate mass spectrum acquisition, integrate particle diameter, time stamp and spectrum information output, and transmit the data to the host processing software through a USB or Ethernet interface.

[0019] The single-nanoparticle mass spectrum analysis method comprises the following steps: Step 1, after the nanoparticle sampling enters the condensation growth area, the nanoparticle is focused into a vacuum environment by an aerodynamic lens; Step 2, a significant scattering signal is generated in the diameter measurement area; Step 3, the control module receives the signal and calculates the time of flight; Step 4, when the particle enters the preheating ionization area, the CO2 laser is accurately triggered to perform instantaneous heating, and the surface condensate or the inner core is evaporated; Step 5, then the ionization laser is emitted, and the positive and negative ions are formed by high-energy pulse laser ionization; Step 6, the ions enter the TOF-MS by electric field acceleration, and the positive and negative spectrum graphs are recorded synchronously.

[0020] The beneficial effects of the present application are as follows: 1. The present application can be effectively triggered by the laser diameter measurement system by increasing the size of the nano-aerosol particles with a particle size less than 100 nm to >300 nm after condensation growth, so as to avoid the problems of energy absorption, ionization efficiency reduction and spectrum background increase caused by the liquid layer in the laser ionization area. A high time response laser preheating vaporization module is designed before entering the ionization area to realize the rapid heating and vaporization treatment of the particle surface condensate, the laser preheating vaporization module can completely evaporate the condensate and improve the ionization efficiency of the core; the laser preheating vaporization module can effectively reduce the fragment ions of organic aerosol, and the spectrum processing can analyze the nano-particles such as organic and inorganic particles.

[0021] The present application can realize efficient optical triggering and mass spectrum component analysis of nano-particles, and the sub-modules work cooperatively to realize real-time single-particle chemical component analysis of nano-aerosol. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows, and the drawings described in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0023] Figure 1 is a system schematic diagram of the present application; Figure 2 is a work flow diagram of the present application. DETAILED DESCRIPTION

[0024] The present application will be further described in detail below in combination with the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0025] It should be noted that the terms "first", "second" and the like are used only for the purpose of description and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0026] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "fixation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between the components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0028] In the above description, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0029] Please see Figure 1 - Figure 2 This invention provides a method for mass spectrometry analysis of the composition of a single nanoparticle, comprising: The condensation growth module is used to grow ultrafine particles that cannot be detected by optical triggering to the optically measurable range; by condensing and growing nano-aerosol particles with a diameter of less than 100 nm, their size is increased to >300 nm, so that they can be effectively triggered by the laser diameter measurement system.

[0030] The sample introduction module, consisting of a gas flow balance interface, an ablator, a critical orifice, and an aerodynamic lens, is used to introduce the sample. Diameter measurement module, after the particles pass through the focused beam, enter the region of the double-beam laser diameter measurement system, two continuous lasers have a fixed interval in space, and when the particles pass through, will scatter the two lasers in turn, and the time difference of the scattering peaks is calculated through the light detection system to obtain the aerodynamic diameter. This signal is also used as a reference for subsequent laser triggering and pre-heating timing. Laser pre-heating vaporization module, used to realize non-contact and rapid vaporization treatment of the surface of the particles. A laser is used as the light source, and the laser is selected and matched according to the absorption characteristics of the condensing agent in the infrared wave band to realize efficient light-heat conversion. The laser completely evaporates the condensing agent adsorbed on the surface of the particle within a few microseconds, so that the inner core of the particle is exposed to the ionization region and enters the subsequent ionization process. The laser pre-heating vaporization module has the characteristics of fast response speed, no mechanical contact, controllable energy, and compact structure. After pre-heating treatment, the liquid on the surface of the particle is removed, and the inner core will exhibit a solid residue or synchronous vaporization according to its physical properties. The laser pre-heating vaporization module can completely evaporate the condensing liquid and improve the ionization efficiency of the inner core. It can also effectively reduce the fragment ions of organic aerosols, and the organic and inorganic nanoparticles can be analyzed through spectrum processing.

[0031] High-energy laser ionization module, after the pre-heating vaporization treatment, the condensing agent on the surface of the particle is completely vaporized, and the remaining gaseous molecules or solid residue core will remain in the main ionization region. In this region, a high-energy pulsed laser is used for irradiation to realize rapid ablation ionization and form positive and negative ions for subsequent mass spectrum analysis. Through the design of the high-energy laser ionization module, rapid laser vaporization and ionization at the single particle level can be realized, and stable positive and negative ion signals can be generated, which is suitable for high time resolution analysis of complex aerosol components (such as organic fragments, metal elements, and inorganic salts). Dual-polarity time-of-flight mass spectrometry module, ions enter the time-of-flight mass spectrometry channel under the acceleration of an electric field. A dual-polarity TOF structure is used to simultaneously collect positive and negative ion spectra, realize element-level analysis and organic fragment analysis, and use a CO2 laser for pre-heating vaporization to reduce the formation of fragment ions and make the characteristic peaks of the substance more prominent. Through high-resolution mass spectrometry and spectrum processing, the organic components and condensing agents in the organic aerosol can be distinguished.

[0032] In this embodiment, preferably, the condensation growth module includes: Saturation device, used to evaporate the liquid condensing agent into a stable concentration of vapor, and mix with the carrier gas to form a highly saturated or supersaturated gas environment for subsequent particle condensation growth; Condenser, pipeline made of heat insulation or temperature control material, vapor is induced to condense on the surface of particles through the temperature gradient of inner wall; by controlling the condensation length and temperature difference, particles grow; a cold trap or drying section is provided at the outlet end to capture excess vapor, preventing a large amount of uncondensed vapor from leaking to the downstream system; the surface of the grown particles is coated with a liquid layer of condensing agent with a thickness of tens to hundreds of nanometers, which is beneficial to subsequent diameter measurement.

[0033] In this embodiment, preferably, the gas flow balance interface is used to stabilize the pressure and flow rate in the sample introduction path, ensuring that the aerodynamic lens can work normally under constant flow; the dissolver is composed of porous activated carbon or zeolite and is arranged before the critical hole for adsorbing and removing the incompletely condensed organic condensing agent vapor to prevent it from entering the downstream ionization and mass spectrometry system to cause background fluctuation interference; the critical small hole has a diameter of 0.1mm-0.2mm and is located in the main sample introduction path for limiting the total sample flow, so that the system operates under stable and near-critical flow conditions, avoiding the influence of flow fluctuation on measurement accuracy; the aerodynamic lens is composed of single lenses with different apertures, the front end vacuum degree is 200-300Pa, and the focusing range is 100nm-5μm, which is used to collimate and focus the grown aerosol particles to form a stable narrow beam particle flow for the laser diameter measurement system to accurately capture and subsequent laser ionization mass spectrometry analysis.

[0034] In this embodiment, preferably, the scattering signal generated by the diameter measurement module is collected by a high-sensitivity photomultiplier tube or avalanche photodiode, and the speed and particle size after growth data are output in real time with a time sequence card.

[0035] In this embodiment, preferably, the laser in the laser preheating vaporization module is selected from one of CO2 laser, near-infrared laser, ceramic heating element or microwave source.

[0036] In this embodiment, preferably, the high-energy laser ionization module uses a pulsed laser as the main energy source, and the typical laser output energy is 0.1-10mJ / pulse to adapt to the ionization requirements of particles with different compositions and sizes, and the pulse duration is set in the range of 3-50ns to ensure that the laser energy is released quickly in a very short time to realize instantaneous ionization to form positive and negative ions. The laser beam and particle flight path can be vertically irradiated or obliquely arranged in space to improve the hit rate and ionization efficiency, and the specific arrangement is flexible according to the design of optical window and space constraints.

[0037] In the embodiment, preferably, the high-energy laser ionization module supports adjustable laser energy to adapt to the excitation needs of different types of particles, for example, lower energy is suitable for ionization of organic matter, and higher energy is suitable for ionization of difficult-to-ionize metal oxides or mineral cores; in order to realize time accurate matching, the triggering time of the ionization laser is uniformly managed by a high-precision timing control card, and the time delay difference with the pre-heating laser excitation signal is controlled within 0-10 mu s, so as to ensure that the particles are ionized after completing the condensate vaporization, and ideal energy coupling efficiency and ionization effect are obtained.

[0038] In the embodiment, preferably, the timing control adopts an FPGA or a high-performance MCU as a core control unit to realize timing from the diameter measurement signal, control of the pre-heating laser to be triggered before the particles arrive, and accurate triggering of the pre-heating vaporization laser and the ionization laser.

[0039] In the embodiment, preferably, the data processing module coordinates mass spectrum acquisition, integrates particle size, time stamp and spectrum information output, and transmits data to a host processing software through a USB or Ethernet interface.

[0040] In the embodiment, preferably, the following steps are included: Step 1, after the nanoparticle sample enters the condensation growth area, the particles are focused into a vacuum environment through an aerodynamic lens; Step 2, a significant scattering signal is generated in the diameter measurement area; Step 3, the control module receives the signal and calculates the time of flight; Step 4, when the particles enter the pre-heating ionization area, the CO2 laser is accurately triggered to perform instantaneous heating to evaporate the surface condensate or the core; Step 5, then the ionization laser is emitted to form positive and negative ions by high-energy pulsed laser ionization; Step 6, the ions enter the TOF-MS through the electric field acceleration, and the positive and negative spectrum graphs are recorded synchronously.

[0041] The working principle and use process of the application are as follows: when the nanoparticle sample enters the condensation growth module, first, the particle size is significantly increased through heterogeneous condensation in the supersaturated vapor environment generated by the saturator. After the growth of the particles, the particles flow through the sample inlet module, and the solvent eroder effectively adsorbs the residual condensate vapor after the flow field is stabilized at the gas flow balance interface; the critical orifice maintains the system in a critical flow state; and the aerodynamic lens focuses the particles into a narrow beam. The particle beam enters the diameter measurement module, passes through two fixed-interval lasers in turn, captures the scattering light signal through a photodetector and calculates the time difference, and the aerodynamic diameter and speed parameters of the particles are obtained in real time.

[0042] At this time, the time sequence control module accurately calculates the time when the particle reaches the preheating area according to the diameter measurement signal. When the target particle reaches the laser preheating vaporization area, the CO2 laser is triggered instantaneously, and the infrared laser (wavelength about 10.6 μm) output by the CO2 laser is efficiently absorbed by the condensing agent, and the complete vaporization of the liquid layer on the surface of the particle is realized within microseconds. This process not only completely removes the coating layer, but also fully exposes the inner core, while avoiding excessive pyrolysis of the organic components.

[0043] The exposed particle core then enters the high-energy laser ionization area. The pulsed laser (typical wavelength 266 nm or 193 nm) is triggered after a predetermined delay time (usually 0-10 μs) under accurate time sequence control, and the high-energy density beam (0.1-10 mJ / pulse) causes the inner core material to be instantaneously ablated and ionized, generating positive and negative charged particles containing element ions and molecular fragments. This process is adapted to the analysis requirements of different chemical compositions by adjusting the laser energy (such as lower energy for soft ionization of organic components, and higher energy for mineral / metal ionization).

[0044] The generated bipolar ions are accelerated into the time-of-flight mass analyzer (TOF-MS) under the action of a strong electric field. The bipolar TOF with a reflective design synchronously separates positive and negative ions through mirror electric fields, and the positive and negative ions fly along two independent paths, respectively. When the ions reach the microchannel plate (MCP) detector, they are converted into mass signals based on the time-of-flight difference, and the positive and negative ion mass spectra are recorded synchronously by a high-speed data acquisition system. Finally, the time signal is converted into mass-to-charge ratio (m / z) information by a time-to-digital converter (TDC) or a high-speed ADC, and combined with the real-time recorded particle size and time stamp data, the synchronous analysis of single particle multi-component (element / molecule) is realized. The entire analysis process can be completed within milliseconds, and has the core capability of real-time online analysis of the chemical composition of aerosol single particles.

[0045] The above only describes some embodiments of the present application. For those skilled in the art, without departing from the inventive concept, several modifications and improvements can be made, which are all within the protection scope of the present application.

Claims

1. A mass spectrometry instrument, characterized by, The application relates to a method for measuring the size of an aerosol particle, and a device for measuring the size of an aerosol particle. The method comprises the following steps: a condensation growth module is used to increase the size of superfine particles which cannot be detected by optical triggering to the range of optical measurement; a sample injection module is used to inject the sample; a diameter measurement module is used for measuring the diameter of the particles after the particles are focused into a beam, two continuous laser beams are fixed at a certain interval in space, and the two laser beams are scattered in sequence when the particles pass through, and the aerodynamic diameter of the particles is obtained by calculating the signals of the two laser beams, the signals are used as the reference for subsequent laser triggering and preheating timing; a laser preheating and vaporization module is used for non-contact and rapid vaporization treatment of the surface of the particles, so that the core of the particles is exposed to an ionization area and enters a subsequent ionization process; a high-energy laser ionization module is used for irradiating the remaining gaseous molecules or solid residual core of the particles after the preheating and vaporization treatment of the surface of the particles by a high-energy pulsed laser, so that the particles are quickly ablated and ionized to form positive and negative ions, and the positive and negative ions are used for subsequent mass spectrum analysis; 2. A mass spectrometer according to claim 1, wherein, a dual-polarity time-of-flight mass spectrum module is used for accelerating the ions in an electric field to enter a time-of-flight mass spectrum channel, and the dual-polarity TOF structure is adopted to synchronously collect positive and negative ion spectrum diagrams, so that element-level analysis and organic fragment analysis are realized, and the organic components and condensers in the organic aerosol are distinguished through high-resolution mass spectrum and spectrum processing. The condensation growth module comprises: a saturator which is used for evaporating liquid condensers into stable concentration vapor, mixing the vapor with carrier gas to form a highly saturated or supersaturated gas environment for subsequent particle condensation growth; 3. A mass spectrometry instrument according to claim 1, wherein, a condenser which is made of heat insulation or temperature control material, and is used for inducing vapor to condense on the surface of the particles through the temperature gradient of the inner wall; the condenser is used for increasing the particles by controlling the condensation length and temperature difference; a cold trap or a drying section is arranged at the outlet end of the condenser to capture excess vapor and prevent a large amount of uncondensed vapor from leaking to the downstream system; and the surface of the increased particles is coated with a liquid layer of condensers with a thickness of dozens to hundreds of nanometers, which is beneficial to the subsequent diameter measurement. The sample injection module comprises a gas flow balance interface, a dissolution eroder, a critical orifice and an aerodynamic lens, the gas flow balance interface is used for stabilizing the pressure and flow rate in the sample injection path, and ensuring that the aerodynamic lens can normally work under constant flow rate; the dissolution eroder is composed of porous activated carbon or zeolite, and is arranged before the critical orifice and used for adsorbing and removing the organic condensate vapor which is not completely condensed, so as to prevent the organic condensate vapor from entering the downstream ionization and mass spectrum analysis system and causing background fluctuation interference; the critical orifice has a pore diameter of 0.1mm-0.2mm, is arranged in the main sample injection path, and is used for limiting the total sample flow rate, so that the system can work under stable and near-critical flow conditions, and the influence of flow fluctuation on the measurement accuracy is avoided; and the aerodynamic lens is composed of single lenses with different pore diameters in multiple stages, has a vacuum degree of 200-300Pa at the front end, and has a focusing range of 100nm-5mu m, and is used for collimating and focusing the increased aerosol particles to form a stable narrow beam particle flow, so that the laser diameter measurement system can accurately capture and the subsequent laser ionization mass spectrum analysis can be performed.

4. The mass spectrometer of claim 1, wherein, The scattering signal generated by the sizing module is collected by a high-sensitivity photomultiplier tube or avalanche photodiode, and the speed and growth particle size data are output in real time with a timing card.

5. The mass spectrometer of claim 1, wherein, The laser in the laser preheating vaporization module is selected from one of a CO2 laser, a near-infrared laser, a ceramic heating element, or a microwave source.

6. The mass spectrometer of claim 1, wherein, The high-energy laser ionization module uses a pulsed laser as the main energy source, with a typical laser output energy of 0.1-10 mJ / pulse to meet the ionization needs of particles of different compositions and sizes, and the pulse duration is set in the range of 3-50 ns.

7. A mass spectrometer according to claim 1, wherein, The high-energy laser ionization module supports adjustable laser energy to adapt to the excitation needs of different types of particles, and the triggering time of the ionization laser is uniformly managed by a high-precision timing control card, and the time delay difference with the preheating laser excitation signal is controlled within the range of 0-10 μs to ensure that the particles are ionized after completing the condensate vaporization, achieving ideal energy coupling efficiency and ionization effect.

8. A mass spectrometry instrument according to claim 1, wherein, Further comprising: Timing control, using FPGA or high-performance MCU as the core control unit, starting timing from the sizing signal, triggering the preheating laser before the particles arrive, and accurately triggering the preheating vaporization laser and ionization laser.

9. A mass spectrometry instrument according to claim 1, wherein, Further comprising: A data processing module coordinates mass spectrum acquisition, integrates particle size, timestamp, and spectrum information output, and transmits data to the host processing software through a USB or Ethernet interface.

10. The method of claim 1, wherein the mass spectrometry instrument is a single nanoparticle composition mass spectrometry instrument. The method comprises the following steps: Step 1, after the nanoparticles are sampled into the condensation growth area, they are focused into a vacuum environment by an aerodynamic lens; Step 2, a significant scattering signal is generated in the sizing area; Step 3, the control module receives the signal and calculates the time of flight; Step 4, when the particles enter the preheating ionization area, the CO2 laser is accurately triggered for instantaneous heating to evaporate the surface condensate or the core; Step 5, then the ionization laser is emitted to form positive and negative ions by high-energy pulsed laser ionization; Step 6, the ions are accelerated into the TOF-MS by an electric field, and the positive and negative spectra are recorded simultaneously.

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