CN115629118A

CN115629118A - Mass spectrometry device and mass spectrometry method

Info

Publication number: CN115629118A
Application number: CN202211358018.XA
Authority: CN
Inventors: 苏展民; 黄志锰; 杜绪兵; 李绚; 黄罗旭
Original assignee: Guangdong Max Scientific Instrument Innovation Research Institute
Current assignee: Guangdong Max Scientific Instrument Innovation Research Institute
Priority date: 2022-11-01
Filing date: 2022-11-01
Publication date: 2023-01-20

Abstract

The embodiment of the invention discloses mass spectrometry equipment and a mass spectrometry method, and relates to the field of detection equipment, wherein the mass spectrometry equipment comprises: the device comprises a sample introduction device, a diameter measuring laser device, a linear array detection device, an ionization laser device, a quality analysis device and a vacuum cavity; the vacuum cavity is connected with the output end of the sample feeding device, and the quality analysis device is arranged in the vacuum cavity; the sample feeding device is used for converging particles in the aerosol into a particle beam; the diameter measuring laser device is used for emitting pulse diameter measuring laser to irradiate the particles in the particle beam; the linear array detection device is used for obtaining the flight speed of the particles according to the obtained imaging information of the particles; the ionization focus of the ionization laser device is arranged in the flight path of the particle beam, and the ionization laser device is used for ionizing particles to obtain ions; the mass analysis device is used for detecting ions to obtain the mass spectrum information of the aerosol.

Description

Mass spectrometry apparatus and mass spectrometry method

Technical Field

The invention relates to the field of detection equipment, in particular to mass spectrometry equipment and a mass spectrometry method.

Background

The aerosol detection mass spectrometer is important equipment for detecting the aerodynamic diameter and the atmospheric pollution components of single-particle aerosol in real time and determining the source of the formed aerosol. Generally, in the existing aerosol detection mass spectrometer, semiconductor continuous laser is used as diameter measuring laser to measure the diameter of aerosol, then the aerosol is ionized, and ions formed by the ionization of the aerosol are detected through a mass spectrometer in the aerosol detection mass spectrometer.

However, when the particle size of the aerosol is smaller than the wavelength of the diameter measuring laser, the scattering intensity of the particles will be subject to rayleigh scattering, i.e. the intensity of the particle scattered by the diameter measuring laser is proportional to the incident light intensity and inversely proportional to the 4 th power of the incident light wavelength. The existing semiconductor continuous laser has longer wavelength and lower power, and when the particle size of aerosol is smaller, a scattered light signal generated by irradiating particles with diameter measuring laser is very weak. The existing photoelectric detector is difficult to detect the scattered light signals of particles, so that the reliability of the mass spectrum detection result of single-particle aerosol obtained by an aerosol detection mass spectrometer is poor.

Disclosure of Invention

In view of the above, the present invention provides a mass spectrometry apparatus and a mass spectrometry method to solve at least one of the above problems, so as to solve the problem of poor reliability of the mass spectrometry detection result of the single particle aerosol.

In a first aspect, the present application provides a mass spectrometry apparatus comprising: the device comprises a sample introduction device, a diameter measuring laser device, a linear array detection device, an ionization laser device, a quality analysis device and a vacuum cavity;

the vacuum cavity is connected with the output end of the sample feeding device, and the mass analysis device is arranged in the vacuum cavity;

the sample feeding device is used for converging particles in the aerosol into the particle beam;

the diameter measuring laser device is used for emitting pulse diameter measuring laser to irradiate the particles in the particle beam;

the linear array detection device is used for obtaining the flight speed of the particles according to the obtained imaging information of the particles;

the ionization focus of the ionization laser device is arranged in the flight path of the particle beam, and the ionization laser device is used for ionizing the particles to obtain ions;

the mass analysis device is used for detecting the ions to obtain the mass spectrum information of the aerosol.

With reference to the first aspect, in a first possible implementation manner, the mass spectrometry apparatus further includes a photodetection device;

the photoelectric detection device is used for acquiring scattered light signals of the particles and generating detection signals according to the scattered light signals, wherein the detection signals are used for adjusting the exposure on-off state of the linear array detection device.

With reference to the first possible implementation manner of the first aspect, in a second possible implementation manner, the mass spectrometry apparatus further includes a light collection device and an imaging device;

the light collection device is arranged between the photoelectric detection device and the flight path of the particle beam, and the imaging device is arranged between the linear array detection device and the flight path of the particle beam;

the collection focus of the light collection device and the imaging focus of the imaging device are sequentially far away from the sample injection device, the included angle between the incident direction of the diameter measuring laser device and the flight path of the particle beam is a preset angle, and the collection focus and the imaging focus are both in the light spot of the pulse diameter measuring laser;

the light collection device is used for converging a scattered light signal generated when the pulse diameter measuring laser irradiates the particles to the photoelectric detection device;

the imaging device is used for imaging the position information of the particles to the linear array detection device when the particles are irradiated by the pulse diameter measuring laser.

With reference to the first possible implementation manner of the first aspect, in a third possible implementation manner, the mass spectrometry apparatus further includes a control device;

the control device is respectively connected with the photoelectric detection device and the linear array detection device;

the control device is used for adjusting the exposure switch state of the linear array detection device according to the received detection signal.

With reference to the third possible implementation manner of the first aspect, in a fourth possible implementation manner, the control device is further connected to the ionization laser device;

the control device is also used for triggering the ionization laser device to emit laser pulses according to the flight speed of the particles.

With reference to the third possible implementation manner of the first aspect, in a fifth possible implementation manner, the control device is further configured to obtain an aerodynamic particle size of the particle according to a flight speed of the particle.

With reference to the first aspect, in a sixth possible implementation manner, the diameter measuring laser device is further configured to emit pulsed diameter measuring laser with a preset repetition frequency to irradiate particles in the particle beam, where a value range of the preset repetition frequency is 1kHz to 10MHz.

In a second aspect, the present application provides a method of mass spectrometry for use in a mass spectrometry apparatus according to the first aspect, the method comprising:

converging particles in the aerosol into particle beams, controlling the diameter measuring laser device to emit pulse diameter measuring laser, and adjusting the linear array detection device to be in an exposure starting state;

obtaining the flight speed of the particles according to the imaging information obtained by the linear array detection device within the exposure time;

triggering the ionization laser device to ionize the particles based on the flying speed to obtain ions;

and detecting ions entering the mass analysis device to obtain the mass spectrum information of the aerosol.

With reference to the second aspect, in a first possible implementation manner, the obtaining the flight speed of the particle according to the imaging information acquired by the linear array detection device within the exposure time includes:

and obtaining the flight speed of the particles according to the imaging information acquired by the linear array detection device within the exposure time and the pulse interval of the pulse diameter measuring laser.

With reference to the second aspect, in a second possible implementation manner, the triggering, based on the flight speed, the ionization laser device to ionize the particles to obtain ions includes:

obtaining the time of the particles reaching the ionization focus of the ionization laser device according to the position of the ionization focus and the flight speed;

and triggering the ionization laser device to ionize the particles based on the time to obtain ions.

The present application provides a mass spectrometry apparatus comprising: the device comprises a sample introduction device, a diameter measuring laser device, a linear array detection device, an ionization laser device, a quality analysis device and a vacuum cavity; the vacuum cavity is connected with the output end of the sample feeding device, and the mass analysis device is arranged in the vacuum cavity; the sample feeding device is used for converging particles in the aerosol into the particle beam; the diameter measuring laser device is used for emitting pulse diameter measuring laser to irradiate the particles in the particle beam; the linear array detection device is used for obtaining the flight speed of the particles according to the obtained imaging information of the particles; the ionization focus of the ionization laser device is arranged in the flight path of the particle beam, and the ionization laser device is used for ionizing the particles to obtain ions; the mass analysis device is used for detecting the ions to obtain the mass spectrum information of the aerosol. Compared with the existing semiconductor continuous laser, the pulse diameter measuring laser device has shorter wavelength and higher peak power, so that stronger particle scattering optical signals of aerosol are obtained, and the reliability of the aerosol mass spectrum detection result is improved. Meanwhile, the linear array detection device realizes accurate measurement of the flight speed of the particles and accurate positioning of the ionization position.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings required to be used in the embodiments will be briefly described below, and it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope of the present invention. Like components are numbered similarly in the various figures.

FIG. 1 shows a schematic view of a first configuration of a mass spectrometry apparatus provided in an embodiment of the present application;

FIG. 2 shows a schematic diagram of a second configuration of a mass spectrometry apparatus provided by an embodiment of the present application;

fig. 3 is a schematic view of a first application scenario of a linear array detection apparatus provided in an embodiment of the present application;

fig. 4 is a schematic view illustrating a second application scenario of the linear array detection apparatus provided in the embodiment of the present application;

FIG. 5 is a schematic diagram illustrating a third configuration of a mass spectrometer device provided by an embodiment of the present application;

FIG. 6 shows a flow chart of a method of mass spectrometry provided by an embodiment of the present invention.

Description of the main element symbols:

100-a mass spectrometry device; 110-sample introduction device, 120-diameter measuring laser device, 130-linear array detection device, 140-ionization laser device, 150-mass analysis device, 160-photoelectric detection device, 170-light collection device, 180-imaging device and 190-control device; 151-vacuum chamber, 152-first mass analysis device, 153-second mass analysis device; 210-pulsed caliper laser, 220-particles.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

Hereinafter, the terms "including", "having", and their derivatives, which may be used in various embodiments of the present invention, are only intended to indicate specific features, numbers, steps, operations, elements, components, or combinations of the foregoing, and should not be construed as first excluding the existence of, or adding to, one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing.

Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments of the present invention belong. The terms (such as terms defined in a commonly used dictionary) will be construed to have the same meaning as the contextual meaning in the related art and will not be construed to have an idealized or overly formal meaning unless expressly so defined in various embodiments of the present invention.

Example 1

Referring to fig. 1, fig. 1 shows a schematic diagram of a first structure of a mass spectrometer apparatus according to an embodiment of the present disclosure. Exemplarily, the mass spectrometry apparatus 100 in fig. 1 comprises: a sample introduction device 110, a diameter measuring laser device 120, a linear array detection device 130, an ionization laser device 140, a mass analysis device 150 and a vacuum cavity 151;

the vacuum chamber 151 is connected with the output end of the sample injection device 110, and the mass analysis device 150 is arranged in the vacuum chamber 151;

the sample feeding device 110 is used for converging the particles 220 in the aerosol into a particle beam;

the diameter measuring laser device 120 is used for emitting pulse diameter measuring laser 210 to irradiate the particles 220 in the particle beam;

the linear array detection device 130 is configured to obtain the flight speed of the particle 220 according to the obtained imaging information of the particle 220;

the ionization focus of the ionization laser device 140 is arranged in the flight path of the particle beam, and the ionization laser device 140 is used for ionizing the particles 220 to obtain ions;

the mass analysis device 150 is configured to detect the ions, so as to obtain mass spectrum information of the aerosol.

In fig. 1, the broken line indicates the flight path of the particle beam, and the solid line indicates the propagation path of light. When mass spectrum information of the aerosol to be detected needs to be generated, the aerosol to be detected enters the sample feeding device 110, and the sample feeding device 110 accelerates the aerosol to be detected and converges the aerosol into particle beams. Specifically, the sample injection device 110 may be an aerodynamic lens, or a nozzle, or a capillary, and the like, which is not described herein. For easy understanding, the sample injection device 110 of the present application is an aerodynamic lens, and the aerodynamic lens has the advantages of large sample injection pressure difference, small particle beam width, and the like. The caliper laser device 120 is configured to emit pulsed caliper laser 210 to laser irradiate particles 220 in the particle beam. The diameter measuring laser device 120 can be implemented by a pulse laser, and can be a solid laser in general.

The vacuum cavity 151 is connected with the output end of the sample injection device 110, and after the sample injection device 110 converts the aerosol into the particle beam, the particles 220 with small particle size enter the vacuum cavity 151 to fly at a constant speed. The scattered light signals of the particles are imaged into the line array detection device 130, and since a plurality of pulses of the pulse diameter measuring laser 210 sequentially act on the particles 220, the line array detection device 130 obtains imaging information with a plurality of signal peak packets. The linear array detection device 130 obtains the flight speed of the particle 220 according to the obtained imaging information of the particle 220, and then determines the time when the particle 220 reaches the ionization focus of the ionization laser device 140 according to the flight speed of the particle 220. Specifically, the line detecting Device 130 is an arbitrary one-dimensional photodetector array, and may be a Device such as a linear-array CCD (Charge-coupled Device), which is not limited herein. The exposure triggering response is carried out through the photoelectric detectors in the photoelectric detector array, and the exposure time is adjusted, so that the current noise of continuous exposure is reduced, and the signal-to-noise ratio of detection is improved. It is to be understood that the duration of the exposure time may be slightly longer than the time for the particles 220 to fly through the imaging range of the line detection device 130. When the particles 220 of the particle beam reach the ionization focus of the ionization laser device 140, the ionization laser device 140 emits pulse impact laser to thermally desorb and ionize the particles 220, and ions of the particles 220 are obtained. After the ions enter the mass analysis device 150, the mass analysis device 150 separates the ions according to the mass-to-charge ratio of the ions, and analyzes and detects the ions to obtain the mass spectrum information of the aerosol to be detected.

Compared with the existing semiconductor continuous laser, the pulse diameter measuring laser 210 emitted by the diameter measuring laser device 120 has shorter wavelength and higher peak power, so that stronger aerosol particle 220 scattered light signals are obtained, and the reliability of the aerosol mass spectrum detection result is improved.

The mass spectrometry apparatus 100 further comprises a photodetector device 160;

the photoelectric detection device 160 is configured to obtain a scattered light signal of the particle 220, and generate a detection signal according to the scattered light signal of the particle 220, where the detection signal is used to adjust an exposure on-off state of the linear array detection device 130.

The pulsed caliper laser 210 laser irradiates a particle 220 in the particle beam, and the particle 220 reacts with a pulse of the pulsed caliper laser 210 to generate a scattered light signal or a fluorescence signal. When the photoelectric detection device 160 detects the optical signal of the particle 220, the optical signal is converted into an electrical signal, that is, a detection signal for adjusting the exposure on-off state of the linear array detection device 130, so that the linear array detection device 130 is adjusted to be in the exposure on state by the detection signal, and the linear array detection device 130 is triggered to detect the flight speed of the particle 220. It should be understood that the photo-detecting device 160 may be any single-detection-point photo-detector, and may be a PMT (photomultiplier tube) with high gain and high sensitivity, which is not limited herein.

In an optional example, the mass spectrometry apparatus 100 further comprises a light collection device 170 and an imaging device 180;

the light collection device 170 is disposed between the photo detection device 160 and the flight path of the particle beam, and the imaging device 180 is disposed between the line detection device 130 and the flight path of the particle beam;

the collection focus of the light collection device 170 and the imaging focus of the imaging device 180 are sequentially far away from the sample introduction device 110, an included angle between the incident direction of the diameter measuring laser device 120 and the flight path of the particle beam is a preset angle, and the collection focus and the imaging focus are both in the light spot of the pulse diameter measuring laser 210;

the light collecting device 170 is configured to converge a scattered light signal generated when the pulsed caliper laser 210 irradiates the particle 220 to the photodetection device 160;

the imaging device 180 is configured to image the position information of the particle 220 to the linear array detection device 130 when the pulsed caliper laser irradiates the particle 220.

Referring to fig. 2, fig. 2 is a schematic diagram illustrating a second structure of a mass spectrometer according to an embodiment of the present disclosure. Exemplarily, a part of the device arrangement of the mass spectrometry apparatus 100 of the present application is omitted in the drawings for the convenience of understanding of the present application. In fig. 2, the dashed line indicates the flight path of the particle beam, and the solid line indicates the propagation path of light.

The angle between the incident direction of the pulsed diameter measuring laser 210 of the diameter measuring laser device 120 and the flight path of the particle beam is a preset angle, wherein the preset angle is according to the actual requirement, the incident direction may be perpendicular to the flight path, and the incident direction may also be perpendicular to the flight path, which is not limited herein. For ease of understanding, in the embodiment of the present application, the incident direction of the pulsed caliper laser 210 of the caliper laser device 120 is at an angle of 5 degrees to the flight path of the particle beam. In order to avoid the deposition of the particle beam on the lens of the caliper laser device 120 and prevent the transmittance of the lens from being attenuated after the caliper laser device 120 is used for a long time, which leads to the reduction of the emitted laser energy, the mode that the incident direction of the pulse caliper laser 210 is coaxial with the flight path of the particle beam is not adopted.

The collection focus of the light collection device 170 and the imaging focus of the imaging device 180 are both within the spot of the pulsed caliper laser 210. The light collecting device 170 is used for collecting a scattered light signal generated when the pulsed caliper laser 210 irradiates the particle 220 to a photosensitive surface of the photodetector 160. The light collecting device 170 may be a lens or a lens group, and may also be an ellipsoidal mirror, a spherical mirror, or a parabolic mirror, which is not limited herein.

The imaging device 180 may be an imaging lens or an imaging lens group, and is not limited herein. When the pulsed caliper laser irradiates the particles 220, the imaging device 180 images the position information of the particles to the line array detection device 130. According to the lens amplification principle, the imaging information obtained by the imaging device 180 has a fixed amplification ratio, and the position of the particle 220 exposed by the pulsed caliper laser 210 and the position of the imaging information imaged to the line array detection device 130 have a corresponding relationship. Specifically, taking the imaging device 180 as an imaging lens as an example, the flight distance of the particle 220 is calculated according to the position of the line array detection device 130 and the magnification of the imaging lens. The flying speed of the particle 220 is obtained from the relationship between the flying distance of the particle 220 and the time and speed.

It is to be understood that the mass analyzing device 150 in the present embodiment includes a first mass analyzing device 152 and a second mass analyzing device 153;

the first mass spectrometer 152 is disposed at one side of the flight path of the particle beam, the second mass spectrometer 153 is disposed at the other side of the flight path of the particle beam, and the first and second

mass spectrometers

152 and 153 are symmetrically disposed according to the ionization focus.

After the particles 220 are subjected to laser thermal desorption ionization to obtain ions of the particles 220, the ions may enter the first mass analysis device 152 and the second mass analysis device 153 through the acceleration electrodes. The mass analysis device 150 separates ions according to their mass-to-charge ratios, and performs analysis and detection on the ions to obtain mass spectrum information of the aerosol to be detected.

Referring to fig. 3, fig. 3 is a schematic view illustrating a first application scenario of the line array detection apparatus according to the embodiment of the present application.

The spot focused by the pulsed caliper laser 210 needs to cover the particle 220 in the particle beam and the imaging interval of the imaging information. Exemplarily, if the angle between the incident direction of the diameter-measuring laser device 120 and the flight path of the particle beam is 90 degrees, that is, the pulse diameter-measuring laser 210 is perpendicular to the particle beam direction, the pulse diameter-measuring laser 210 needs to form a light spot with a preset length-width ratio, the width direction of the light spot covers the whole particle beam, and the length of the light spot covers the imaging interval of the imaging information.

Referring to fig. 4 together, fig. 4 shows a schematic view of a second application scenario of the line array detection apparatus provided in the embodiment of the present application.

Illustratively, if the angle between the incident direction of the caliper laser device 120 and the flight path of the particle beam is 0 degrees, the pulsed caliper laser 210 is coaxial with the particle beam. The laser focal depth of the pulsed caliper laser 210 covers the imaging interval of the imaging information, and it is only necessary to determine that the spot of the pulsed caliper laser 210 is larger than the particle beam width. Similarly, in this embodiment, the angle between the incident direction of the diameter-measuring laser device 120 and the flight path of the particle beam is 5 degrees, and it is only necessary to determine that the spot of the pulsed diameter-measuring laser 210 is larger than the width of the particle beam. The included angle between the incident direction of the diameter measuring laser device 120 and the flight path of the particle beam is not 0 degree, so that the particle beam can be prevented from being deposited on the lens of the diameter measuring laser device 120, and the reduction of the transmitted laser energy caused by the attenuation of the transmittance of the lens after the diameter measuring laser device 120 is used for a long time can be prevented. It should be understood that the collection focus of the light collection device 170 and the imaging focus of the imaging device 180 are sequentially away from the sample injection device 110, so that the photoelectric detection device 160 detects, with respect to the linear array detection device 130, a scattered light signal generated when the diameter measuring laser irradiates the particles 220, and then triggers the linear array detection device 130 to adjust to the exposure on state.

Referring to fig. 5, fig. 5 is a schematic diagram illustrating a third structure of a mass spectrometer apparatus according to an embodiment of the present disclosure.

In an optional example, the mass spectrometry apparatus 100 further comprises a control device 190;

the control device 190 is respectively connected to the photoelectric detection device 160 and the linear array detection device 130;

the control device 190 is configured to adjust an exposure on-off state of the linear array detection device 130 according to the received detection signal.

The dashed line in fig. 5 represents the flight path of the particle beam. When the particle 220 interacts with a pulse of the pulsed caliper laser 210, the resulting scattered light signal is focused onto the photosensitive surface of the photodetector 160. The photodetection device 160 converts the scattered light signal in the form of an optical signal into a detection signal in the form of an electrical signal, and transmits the detection signal to the control device 190. The control device 190 sends a trigger signal to the linear array detection device 130 according to the received detection signal, adjusts an exposure on-off state of the linear array detection device 130, and triggers the linear array detection device 130 to perform exposure so as to obtain the flight speed of the particles 220.

In an optional example, the control device 190 is further connected to the ionization laser device 140;

the control device 190 is further configured to trigger the ionization laser device 140 to emit laser pulses according to the flight speed of the particles 220.

After the linear array detection device 130 obtains the flight speed of the particle 220, since the position of the ionization focus of the ionization laser device 140 is known, the control device 190 obtains the time when the particle 220 reaches the ionization focus of the ionization laser device 140 according to the position of the ionization focus and the flight speed of the particle 220. When the particles 220 reach the ionization focus, the control device 190 sends a trigger signal to the ionization laser device 140 to trigger the ionization laser device 140 to emit pulse impact laser, so as to perform thermal desorption and ionization on the particles 220, thereby obtaining the ions of the particles 220.

In an alternative example, the control device 190 is further configured to obtain an aerodynamic particle size of the particle 220 according to a flight speed of the particle 220.

Based on the correspondence between the flying speed of the particle 220 and the aerodynamics, the aerodynamic particle size of the particle 220 can be obtained. The aerodynamic relationship of the particles 220 varies according to the mechanical structure of the sample injection device 110 and the vacuum pressure differential design. Under the condition that the mechanical structure of the sample injection device 110 is determined and the air pressure is stable, the aerodynamic particle size of the particles 220 has a fixed corresponding relationship with the flight speed, and the calibration can be performed based on standard particulate matters with different particle sizes, and fitting is performed by using a polynomial of multiple degree. Fitting requirements can be met by using a cubic polynomial, and further, the aerodynamic particle size of the particles 220 is obtained based on the corresponding relationship between the flight speed of the particles 220 and the aerodynamics.

Exemplarily, the diameter measuring laser device 120 is further configured to emit pulsed diameter measuring laser with a preset repetition frequency to irradiate the particles 220 in the particle beam, where the preset repetition frequency is in a range from 1kHz to 10MHz.

Taking the diameter measuring laser device 120 as an example of a pulse laser, the higher the frequency of the pulse laser, the higher the hitting probability of the particles 220, and the more accurate the time resolution of the measured flying speed. However, when the laser frequency of the pulse laser is too high, the detected signal peaks overlap, and the signal cannot be resolved. In order to improve the reliability of the aerosol mass spectrum detection result, the accurate measurement of the particle flight speed and the accurate positioning of the ionization position are realized. The diameter measuring laser device 120 emits a pulse diameter measuring laser with a preset repetition frequency, and the value range of the preset repetition frequency is 1kHz to 10MHz.

In addition, the wavelength range of the pulsed caliper laser may be 200nm to 1500nm. According to the rayleigh scattering theory, the shorter the laser wavelength, the stronger the scattered light intensity, and the more reliable the small particle measurement result. The caliper laser device 120 uses a pulse laser, and has a higher peak energy and a stronger scattered light intensity at the same average energy as that of the continuous laser pulse laser. In addition, the narrow pulse width of the pulse laser is also helpful for generating laser with shorter wavelength by nonlinear effect, and can also reduce the peak width of the imaging signal peak of the linear array detection device 130 in single exposure. Typically the pulse width of a pulsed laser should be less than 100ns.

Example 2

Referring to fig. 6, fig. 6 is a flow chart illustrating a mass spectrometry method according to an embodiment of the invention. The mass spectrometry method of fig. 6 is applied to the mass spectrometry apparatus 100 according to embodiment 1, and includes the steps of:

s310, converging the particles 220 in the aerosol into a particle beam, triggering the diameter measuring laser device 120 to emit the pulsed diameter measuring laser 210, and adjusting the linear array detection device 130 to an exposure on state.

The aerosol to be detected in the air enters the sample introduction device 110, and the sample introduction device 110 converts the aerosol into particle beams. Exemplarily, in the embodiment of the present application, the angle between the flight direction of the pulsed caliper laser 210 and the particle 220 is 5 degrees, so as to avoid deposition of the particle beam. Meanwhile, the light spot of the pulsed caliper laser 210 is located at the collection focal position of the light collection device 170 and the imaging focal position of the imaging device 180, and the light spot is set to 300um to cover the beam width of the particle beam and make the energy density of the light spot higher. Meanwhile, the focal length of the pulsed caliper laser 210 is 1mm to cover the imaging interval of the imaging information.

The resultant particle beam enters the vacuum chamber 151, and the particles 220 in the vacuum chamber 151 fly at a uniform speed. The particle 220 first flies to the collection focus of the light collection device 170, and the particle 220 interacts with one pulse of the pulsed caliper laser 210 to produce a scattered light signal. The scattered light signal is collected by the light collection device 170 to the photodetector 160. The photodetection device 160 converts the optical signal of the scattered light signal in the form of an optical signal into a detection signal in the form of an electrical signal, and transmits the detection signal to the control device 190. The control device 190 sends a trigger signal to the linear array detection device 130 according to the received detection signal, adjusts an exposure on-off state of the linear array detection device 130, and triggers the linear array detection device 130 to perform exposure.

S320, obtaining the flying speed of the particles 220 according to the imaging information obtained by the linear array detection device 130 within the exposure time.

The particles 220 fly to the imaging focus of the imaging device 180, the imaging device 180 images the scattered light signals into the linear array detection device 130, and since a plurality of pulses of the pulse diameter measuring laser 210 sequentially act on the particles 220, the linear array detection device 130 acquires imaging information of the particles 220, wherein the imaging information has a plurality of signal peak packets. The linear array detection device 130 obtains the flight speed of the particles 220 according to the imaging information of the particles 220.

As an example, the obtaining the flight speed of the particle 220 according to the imaging information obtained by the line array detection device 130 within the exposure time includes:

obtaining the flight speed of the particles 220 according to the imaging information acquired by the linear array detection device 130 and the pulse interval of the pulse diameter measuring laser 210;

according to the imaging information acquired by the linear array detection device 130 and the imaging amplification proportional relation of the imaging device 180, the flight distances of the particles 220 under different laser pulse exposures are obtained. Since the pulse spacing between different pulses of the pulsed caliper laser 210 is constant. The flying speed of the particle 220 is obtained from the flying distance and the pulse interval of the particle 220.

S330, triggering the ionization laser device 140 to ionize the particles 220 based on the flight speed, so as to obtain ions;

the time for which the ionization laser device 140 emits the pulse-striking laser is determined according to the flying speed of the particle 220. When the particles 220 of the particle beam reach the ionization focus of the ionization laser device 140, the ionization laser device 140 emits a pulse impact laser to thermally desorb and ionize the particles 220, and ions of the particles 220 are obtained.

As an example, the triggering the ionization laser device 140 to ionize the particles 220 based on the flight speed to obtain ions includes:

obtaining the time for the particle 220 to reach the ionization focus of the ionization laser device 140 according to the position of the ionization focus and the flight speed;

and triggering the ionization laser device 140 to ionize the particles 220 based on the time to obtain ions.

Since the position of the ionization focus of ionization laser device 140 is known, control device 190 derives the time at which particle 220 reaches the ionization focus of ionization laser device 140 based on the position of the ionization focus and the flight speed of particle 220.

Illustratively, the caliper laser device 120 is an ultraviolet picosecond laser, and the caliper laser device 120 emits pulsed caliper laser 210 with a laser power of 400mW, a wavelength of 355nm, and a repetition frequency of 2 MHz. In the exposure time of the linear array detection device 130, the particles 220 continuously fly, the pulsed caliper laser 210 exposes the particles 220 at time intervals of 500ns, and the linear array detection device 130 continuously acquires images of scattered light signals and performs superposition integration, so that the imaging information acquired by the linear array detection device 130 includes a plurality of equally spaced signal peak packets. Specifically, if the flying speed of the particle 220 is 200m/s, the particle 220 will be exposed once by the pulsed caliper laser 210 every 100um flying, and then superimposed into a plurality of equally spaced signal peak packets. Illustratively, a signal peak package of 1mm between each other and a magnification of 10X of the imaging device 180 results in a flight distance of 0.1mm for the particle 220. Depending on the flight distance and pulse interval of the particles 220, the flying speed of the particles 220 was obtained to be 0.1mm/500ns =200m/s. Assuming that the known position of the ionization focal point is 50nm, it is found that the time when the particle 220 reaches the ionization focal point of the ionization laser device 140 is 250us, that is, after 250us, the ionization laser device 140 emits pulsed laser light to ionize the particle 220, and the ion of the particle 220 is obtained.

S340, detecting the ions entering the mass spectrometer 150 to obtain the mass spectrometry information of the aerosol.

After the ions enter the mass analysis device 150, the mass analysis device 150 separates the ions according to the mass-to-charge ratio of the ions, and analyzes and detects the ions to obtain the mass spectrum information of the aerosol to be detected.

In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other manners. The apparatus embodiments described above are merely illustrative and, for example, the flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

In addition, each functional module or unit in each embodiment of the present invention may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

The functions, if implemented in the form of software functional modules and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention or a part of the technical solution that contributes to the prior art in essence can be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a smart phone, a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention.

Claims

1. A mass spectrometry apparatus, comprising: the device comprises a sample introduction device, a diameter measuring laser device, a linear array detection device, an ionization laser device, a quality analysis device and a vacuum cavity;

2. The mass spectrometry apparatus of claim 1, further comprising a photodetector device;

3. The mass spectrometry apparatus of claim 2, further comprising a light collection device and an imaging device;

the light collecting device is arranged between the photoelectric detection device and the flight path of the particle beam, and the imaging device is arranged between the linear array detection device and the flight path of the particle beam;

4. The mass spectrometry apparatus of claim 2, further comprising a control device;

5. The mass spectrometry apparatus of claim 4, wherein the control means is further connected to the ionization laser means;

6. The mass spectrometry apparatus of claim 4, wherein the control means is further configured to derive an aerodynamic particle size of the particles based on the flight velocity of the particles.

7. The mass spectrometry apparatus of claim 1, wherein the caliper laser device is further configured to emit pulsed caliper laser light at a predetermined repetition rate to irradiate the particles in the particle beam, wherein the predetermined repetition rate is in a range of 1kHz to 10MHz.

8. A method of mass spectrometry for use in a mass spectrometry apparatus according to any one of claims 1 to 7, the method comprising:

triggering the ionization laser device to ionize the particles based on the flight speed to obtain ions;

9. The mass spectrometry method of claim 8, wherein the obtaining of the flight velocity of the particles from the imaging information acquired by the line array detection device within the exposure time comprises:

10. The method of mass spectrometry of claim 8, wherein said triggering the ionization laser device to ionize the particle based on the flight velocity to obtain ions comprises: