Large flow bioaerosol intrinsic fluorescence monitoring device

Abstract

A high-flow bioaerosol intrinsic fluorescence monitoring device includes a high-flow sampling fan, a sampling cup filled with liquid medium, a particle counter placed at the air inlet end, a fluorescence detection unit, a particle filtration unit, a liquid outlet peristaltic pump, a liquid storage unit, a liquid inlet peristaltic pump and a central control unit; the bioaerosol particle sample is concentrated by a high-flow liquid phase sampling technology, and the intrinsic fluorescence of the biological particles is monitored by ultraviolet induced intrinsic fluorescence technology to achieve high-sensitivity and rapid detection of low-concentration bioaerosol particles; the closed-loop liquid path system of the particle filter is adopted, so that the sampling liquid can be reused many times, thereby realizing long-term automatic monitoring of the monitoring device. The present invention can detect multiple information such as the particle concentration, intrinsic fluorescence and intrinsic fluorescence after bleaching of the enriched bioaerosol particle sample, thereby realizing low false alarm rate detection and initial classification of aerosol particles.

Description

Technical Field

[0001] The invention relates to a bioaerosol optical real-time monitoring technology, in particular to a large-flow bioaerosol intrinsic fluorescence monitoring device. Background Art

[0002] Bioaerosols are commonly found in the air environment, and their concentration is generally low, with the concentration of bacteria and other microorganisms in the air being about hundreds per cubic meter. Among the current real-time monitoring technologies for bioaerosols, ultraviolet light-induced intrinsic fluorescence detection technology has achieved good application results in some scenarios due to its many advantages such as strong real-time performance, high degree of automation, and no consumables.

[0003] However, the sampling flow rate of existing intrinsic fluorescence monitoring sensors is generally in the range of 1 to 5 L / min. It has a good practical effect on the early warning of high-concentration bioaerosols after the release of biological terrorist warfare agents, but has a poor response effect on low-concentration bioaerosols under normal circumstances. In order to meet the needs of large-flow sampling, some monitoring devices are equipped with virtual impact concentrators before the fluorescence detector. The virtual impact concentrator can enrich aerosol particles above the cut-off particle size in the large-flow airflow into the small-flow airflow. However, the cut-off particle size of the virtual impact concentrator is generally large and cannot cover aerosol particles with a submicron particle size. Therefore, the fluorescence detection device equipped with a virtual impactor can only detect bioaerosol particles with a relatively large particle size.

[0004] On the other hand, existing bioaerosol fluorescence detection devices are affected by interferences such as haze and cigarettes, and sometimes give false alarms. Summary of the invention

[0005] In view of the above existing problems, the present invention provides a large-flow bioaerosol intrinsic fluorescence monitoring device, which uses a large-flow liquid phase sampling technology to concentrate bioaerosol particle samples, and uses ultraviolet induced intrinsic fluorescence technology to monitor the intrinsic fluorescence of biological particles, thereby realizing high-sensitivity and rapid detection of low-concentration bioaerosol particles; the closed-loop liquid path system of the particle filter can be used repeatedly to enable the sampling liquid to be reused, thereby realizing long-term automatic monitoring of the monitoring device. The device can detect multiple information such as the particle concentration, intrinsic fluorescence, and intrinsic fluorescence after bleaching of the enriched bioaerosol particle sample, thereby realizing low false alarm rate detection and initial classification of aerosol particles.

[0006] The technical solution of the present invention is as follows:

[0007] A high-flow bioaerosol intrinsic fluorescence monitoring device is characterized in that it comprises a high-flow sampling fan, a sampling cup filled with a liquid medium, a particle counter placed at the air inlet end, a fluorescence detection unit, a particle filtering unit, a liquid outlet peristaltic pump, a liquid storage unit, a liquid inlet peristaltic pump and a central control unit.

[0008] The sampling cup is integrally formed by an upper cylindrical section and a lower conical cup shell structure, the conical cup shell structure is used to hold the sampling liquid, the cylindrical upper end of the sampling cup is connected to the large flow sampling fan to form a cyclone sampling device, an airflow connecting pipe is located at a lower position on one side of the cylindrical upper section of the sampling cup, the particle counter is connected to one side of the airflow connecting pipe, a liquid inlet is located at a higher position on the other side of the cylindrical upper section of the sampling cup, an ultraviolet and visible light anti-reflection film is plated on the surface of the conical cup shell of the sampling cup, the conical tip of the conical cup shell of the sampling cup is connected to the liquid storage unit through a pipeline via the particle filtration unit and the liquid outlet peristaltic pump, and another pipeline at the outlet of the liquid storage unit is connected to the liquid inlet of the sampling cup via the liquid inlet peristaltic pump;

[0009] The fluorescence detection unit comprises an ultraviolet light emitting diode, and along the laser output direction of the ultraviolet light emitting diode are the shaping optical component, the detection area of ​​the sampling cup cone and cup shell, and the light trap in sequence. The aerosol particles in the detection area emit intrinsic fluorescence under the irradiation of the laser of the ultraviolet light emitting diode, and the intrinsic fluorescence is collected by the focusing lens group and then incident on the dichroic mirror in parallel. The short-wave fluorescence of the intrinsic fluorescence is reflected by the dichroic mirror and passes through the short-wave filter, the short-wave focusing lens and the first aperture in sequence to reach the first fluorescence detector. The long-wave fluorescence of the intrinsic fluorescence passes through the dichroic mirror and passes through the long-wave filter, the long-wave focusing lens and the second aperture in sequence to reach the second fluorescence detector.

[0010] The detection area (ie, light-sensitive area) of the fluorescence detection unit is located in the lower half of the sampling liquid in the sampling cup.

[0011] The central control unit can control the start and stop of the sampling fan, the particle counter, the fluorescence detection unit, the liquid outlet peristaltic pump and the liquid inlet peristaltic pump, and can also receive the detection results from the particle counter and the fluorescence detection unit.

[0012] The particle filtration unit is a high-efficiency filter suitable for liquids, with a filtration particle size of not less than 0.22 μm, capable of filtering most microbial particles, and a filtration efficiency of not less than 99.9%.

[0013] The working process of the large-flow bioaerosol monitoring device is as follows:

[0014] 1) The liquid inlet peristaltic pump draws about 10 mL of the sampling liquid medium from the liquid storage unit into the sampling cup, and the sampling liquid in the sampling cup forms a wet wall cyclone. After the liquid medium is inlet, the fluorescence detection unit starts to work, excites the sampling liquid, and obtains an optical background signal;

[0015] 2) The high-flow fan and the particle counter start working. After the high-flow fan starts working, the airflow enters the sampling cup from the air inlet through the airflow connecting pipe. A small part of the airflow enters the particle counter and is used for particle concentration measurement to obtain a particle concentration value. Most of the airflow enters the sampling cup and mixes with the liquid medium. The aerosol particles are impacted and mixed into the sampling liquid on the wall of the cup. The aerosol particles are collected in the liquid medium and are sampled and enriched. After the sampling is completed, it is left to stand for more than 10 seconds. At this time, most of the particles including microorganisms settle to the lower part of the sampling liquid.

[0016] 3) The ultraviolet light-emitting diode of the fluorescence detection unit starts to work, and the emitted laser excites the aerosol particles in the sampled liquid. The first fluorescence detector and the second fluorescence detector obtain the first channel intrinsic fluorescence signal and the second channel intrinsic fluorescence signal respectively. After continuous irradiation for several seconds, the intrinsic fluorescence intensity may decay, i.e., bleaching occurs. Different types of bioaerosol particles have different decay rates. The first fluorescence detector and the second fluorescence detector obtain the first fluorescence signal and the second fluorescence signal after bleaching respectively.

[0017] 4) After the fluorescence detection is completed, the liquid outlet peristaltic pump starts to work. Driven by the liquid outlet peristaltic pump, the sample liquid passes through the particle filter unit, and the aerosol particles therein are intercepted by the particle filter unit. The relatively pure sample liquid returns to the liquid storage unit and is reserved for use as a new sample liquid in the subsequent cycle;

[0018] 5) The particle concentration value and fluorescence information are sent to the central control unit so that the central control unit can determine the biological properties and categories of the aerosol particles based on the collected particle concentration value and fluorescence information.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] 1. The high-flow liquid phase sampling technology is used to concentrate the bioaerosol particle samples, and the ultraviolet-induced intrinsic fluorescence technology is used to monitor the intrinsic fluorescence of the biological particles, which can achieve high-sensitivity and rapid detection of low-concentration bioaerosol particles;

[0021] 2. The closed-loop liquid system including the particle filter can make the sampling liquid reused many times, thus realizing the long-term automatic monitoring of the monitoring device.

[0022] 3. This device can detect multiple information such as particle concentration, intrinsic fluorescence, and intrinsic fluorescence after bleaching of the enriched bioaerosol particle sample, based on which low false alarm rate and initial classification of aerosol particles can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1The figure is a schematic diagram of the composition and working principle of the bioaerosol monitoring device of the present invention.

[0024] Figure 2 The figure is a schematic diagram of the composition and principle of the fluorescence detection unit of the bioaerosol monitoring device of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings and embodiments, but the protection scope of the present invention should not be limited thereto.

[0026] like Figure 1 As shown, the high-flow bioaerosol intrinsic fluorescence monitoring device of the present invention comprises a high-flow sampling fan 1, a sampling cup 2 filled with a liquid medium, a particle counter 3 placed at the air inlet end, a fluorescence detection unit 4, a particle filtering unit 5, a liquid outlet peristaltic pump 6, a liquid storage unit 7, a liquid inlet peristaltic pump 8 and a central control unit 9.

[0027] The sampling cup 2 is integrally formed by an upper cylindrical section and a lower conical cup shell structure, the conical cup shell structure is used to hold the sampling liquid, the cylindrical upper end of the sampling cup 2 is connected to the large flow sampling fan 1 to form a cyclone sampling device, an airflow connecting pipe 21 is located at a lower position on one side of the cylindrical upper section of the sampling cup 2, and the particle counter 3 is connected to one side of the airflow connecting pipe 21, and a liquid inlet 22 is located at a higher position on the other side of the cylindrical upper section of the sampling cup 2, and an ultraviolet and visible light anti-reflection film is plated on the surface of the conical cup shell of the sampling cup 2, the conical tip of the conical cup shell of the sampling cup 2 is connected to the liquid storage unit 7 by a pipeline through the particle filter unit 5 and the liquid outlet peristaltic pump 6, and another pipeline at the outlet of the liquid storage unit 7 is connected to the liquid inlet 22 of the sampling cup 2 through the liquid inlet peristaltic pump 8;

[0028] like Figure 2 As shown, the fluorescence detection unit 4 includes an ultraviolet light emitting diode 401, and along the laser output direction of the ultraviolet light emitting diode 401 are the shaping optical component 402, the detection area of ​​the cone cup shell of the sampling cup 2 and the light trap 403. The aerosol particles in the detection area emit intrinsic fluorescence under the irradiation of the laser of the ultraviolet light emitting diode 401, and the intrinsic fluorescence is collected by the focusing lens group 404 and then incident on the dichroic mirror 405 in parallel. The short-wave fluorescence of the intrinsic fluorescence is reflected by the dichroic mirror 405 and then passes through the short-wave filter 410, the short-wave focusing lens 411 and the first aperture 412 in sequence to reach the first fluorescence detector 413. The long-wave fluorescence of the intrinsic fluorescence passes through the dichroic mirror 405 and then passes through the long-wave filter 406, the long-wave focusing lens 407 and the second aperture 408 in sequence to reach the second fluorescence detector 409.

[0029] The detection area (ie, light-sensitive area) of the fluorescence detection unit 4 is located at the lower half of the sampling liquid in the sampling cup 2 .

[0030] The large-flow bioaerosol intrinsic fluorescence monitoring device is characterized in that the central control unit 9 can control the start and stop of the sampling fan 1, the particle counter 3, the fluorescence detection unit 4, the liquid outlet peristaltic pump 6, and the liquid inlet peristaltic pump 8, and can also receive the detection results from the particle counter 3 and the fluorescence detection unit 4.

[0031] The particle filtering unit 5 is a high-efficiency filter suitable for liquids, and its filtering particle diameter is not less than 0.22 μm, which can filter most microbial particles, and the filtering efficiency is not less than 99.9%.

[0032] The working process of the large-flow bioaerosol monitoring device is as follows:

[0033] 1) The liquid inlet peristaltic pump 8 draws about 10 mL of the sampling liquid medium from the liquid storage unit 7 into the sampling cup 2, and the sampling liquid in the sampling cup 2 forms a wet wall cyclone. After the liquid medium is inlet, the fluorescence detection unit 4 starts to work, excites the sampling liquid, and obtains an optical background signal;

[0034] 2) The high-flow fan 2 and the particle counter 3 start working. After the high-flow fan 2 starts working, the air flows through the air flow connecting pipe 21 and enters the sampling cup 2 from the air inlet 22. A small part of the air flows into the particle counter 3 and is used for particle concentration measurement to obtain a particle concentration value. Most of the air flows into the sampling cup 2 and mixes with the liquid medium. The aerosol particles are impacted and mixed into the sampling liquid on the wall of the cup. The aerosol particles are collected in the liquid medium and are sampled and enriched. After the sampling is completed, the sample is left to stand for more than 10 seconds. At this time, most of the particles including microorganisms settle to the lower part of the sampling liquid.

[0035] 3) The ultraviolet light emitting diode 401 of the fluorescence detection unit 4 starts to work, and the emitted laser excites the aerosol particles in the sample liquid. The first fluorescence detector 413 and the second fluorescence detector 409 obtain the first channel intrinsic fluorescence signal and the second channel intrinsic fluorescence signal respectively. After continuous irradiation for several seconds, the intrinsic fluorescence intensity may decay, i.e., bleaching occurs. Different types of bioaerosol particles have different decay rates. The first fluorescence detector 413 and the second fluorescence detector 409 obtain the first fluorescence signal and the second fluorescence signal after bleaching.

[0036] 4) After the fluorescence detection is completed, the liquid outlet peristaltic pump 6 starts to work. Driven by the liquid outlet peristaltic pump 6, the sample liquid passes through the particle filter unit 5, and the aerosol particles therein are intercepted by the particle filter unit 5. The relatively pure sample liquid returns to the liquid storage unit 7 and is reserved for use as a new sample liquid in the subsequent cycle;

[0037] 5) The particle concentration value and fluorescence information are sent to the central control unit 9 so that the central control unit 9 can determine the biological properties and categories of the aerosol particles based on the collected particle concentration value and fluorescence information.

[0038] The device can perform sampling and monitoring work periodically for a long period of time. When the sampling liquid in the liquid storage unit 7 is insufficient, fresh sampling liquid needs to be added.

[0039] Experiments show that the device of the present invention uses a large-flow liquid phase sampling technology to concentrate bioaerosol particle samples, and uses ultraviolet-induced intrinsic fluorescence technology to monitor the intrinsic fluorescence of biological particles, which can achieve high-sensitivity and rapid detection of low-concentration bioaerosol particles; the device includes a closed-loop liquid path system of a particle filter, which allows the sampling liquid to be reused multiple times, thereby achieving long-term automatic monitoring of the monitoring device. The device can detect multiple information such as particle concentration, intrinsic fluorescence, and intrinsic fluorescence after bleaching of the enriched bioaerosol particle sample, thereby achieving low false alarm rate detection and initial classification of aerosol particles.

Claims

1. A high-flow bioaerosol intrinsic fluorescence monitoring device, characterized in that It comprises a large-flow sampling fan (1), a sampling cup (2) filled with a liquid medium, a particle counter (3) arranged at the air inlet end, a fluorescence detection unit (4), a particle filtering unit (5), a liquid outlet peristaltic pump (6), a liquid storage unit (7), a liquid inlet peristaltic pump (8) and a central control unit (9); The sampling cup (2) is integrally formed of an upper cylindrical section and a lower conical cup shell structure, the conical cup shell structure is used to hold the sample liquid, the cylindrical upper end of the sampling cup (2) is connected to the large flow sampling fan (1) to form a cyclone sampling device, an airflow connecting pipe (21) is located at a lower position on one side of the cylindrical upper section of the sampling cup (2), and the particle counter (3) is connected to one side of the airflow connecting pipe (21), and a liquid inlet (22) is located at a higher position on the other side of the cylindrical upper section of the sampling cup (2), and an ultraviolet and visible light anti-reflection film is plated on the surface of the conical cup shell of the sampling cup (2), the conical tip of the conical cup shell of the sampling cup (2) is connected to the liquid storage unit (7) through a pipeline via the particle filter unit (5) and the liquid outlet peristaltic pump (6), and another pipeline at the outlet of the liquid storage unit (7) is connected to the liquid inlet (22) of the sampling cup (2) via the liquid inlet peristaltic pump (8); The fluorescence detection unit (4) comprises an ultraviolet light emitting diode (401), and along the laser output direction of the ultraviolet light emitting diode (401) are a shaping optical component (402), a detection area of ​​the cone cup shell of the sampling cup (2), and a light trap (403) in sequence. Aerosol particles in the detection area emit intrinsic fluorescence under the irradiation of the laser of the ultraviolet light emitting diode (401), and the intrinsic fluorescence is collected by a focusing lens group (404) and incident on a dichroic mirror (405) in parallel. The short-wavelength fluorescence of the intrinsic fluorescence is reflected by the dichroic mirror (405) and sequentially passes through a short-wavelength filter (410), a short-wavelength focusing mirror (411) and a first aperture (412) before reaching a first fluorescence detector (413), while the long-wavelength fluorescence of the intrinsic fluorescence passes through the dichroic mirror (405) and sequentially passes through a long-wavelength filter (406), a long-wavelength focusing mirror (407) and a second aperture (408) before reaching a second fluorescence detector (409).

2. The high-flow bioaerosol intrinsic fluorescence monitoring device according to claim 1 is characterized in that The detection area, i.e. the light sensitive area, of the fluorescence detection unit (4) is located in the lower half of the sampling liquid in the sampling cup (2).

3. The high-flow bioaerosol intrinsic fluorescence monitoring device according to claim 1 is characterized in that The central control unit (9) is used to control the start and stop of the large-flow sampling fan (1), the particle counter (3), the fluorescence detection unit (4), the liquid outlet peristaltic pump (6), and the liquid inlet peristaltic pump (8), and receives the detection results from the particle counter (3) and the fluorescence detection unit (4).

4. The high-flow bioaerosol intrinsic fluorescence monitoring device according to claim 1 is characterized in that The particle filtering unit (5) is a high-efficiency filter suitable for liquids, with a filtering particle size of not less than 0.22 μm, capable of filtering most microbial particles, and a filtering efficiency of not less than 99.9%.

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