JP5099551B2 - Nanoparticle component measuring apparatus and method - Google Patents

Description

The present invention relates to a nanoparticle component measuring apparatus and method for measuring a nano-unit trace component in, for example, exhaust gas discharged from a vehicle.

  In recent years, the complicated mechanism of the problem of air pollution has gradually become clear with the progress of measurement technology. For example, analysis technology enables analysis of trace chemical substances typified by harmful air pollutants, contributing to the elucidation of mechanisms such as atmospheric diffusion and photochemical reactions using simulation. As a result, it has been found that air pollution is diffused as secondary pollutants and secondary particles through photochemical reaction together with primary pollutants which are various chemical substances.

  In addition to these existing air pollution, it has become possible to measure very small particles (hereinafter referred to as “nanoparticles”) of nanometers of 50 nm or less in particulate matter. Problems and health problems are also a concern.

  Although there is a PRTR (Pollutant Release and Transfer Register) system as a measure against environmental pollution, there are additional causes of emissions in order to understand the overall picture and to control new environmental pollution that is of concern in the future.・ Identification of the mechanism is essential.

However, analysis of trace components is difficult, and the current situation is that the whole picture has not yet been elucidated. In particular, regarding air pollution, it is difficult to capture changes in its form, and there is an urgent need for an analytical technique capable of simultaneously measuring direct, multi-element, and multi-components of extremely small quantities of environmental substances.
In addition, there is concern about environmental pollution at the particle size level generated by the future nanotechnology industry, etc., and direct, multi-element, multi-component measurement technology for extremely small amounts of environmental substances is necessary to ensure the safety and security of the public. It has become a key technology.

By the way, in recent chemical component composition measurement, high-sensitivity analysis is required for important measurement chemical species as well as grasping the entire component distribution constituting the measurement target.
This requires analysis characteristics that contradict each other between the “average analysis sensitivity” for the components that make up the measurement target and the “selective analysis sensitivity” for specific components, which cannot be achieved with conventional analysis methods. It is a problem. In elemental composition analysis, it is necessary to decompose and measure the measurement target at the elemental level, and it has been difficult to achieve compatibility with chemical component composition measurement. Therefore, in order to measure multi-elements and multi-components, it is necessary to use a plurality of analytical methods such as GC-MS (Gas Chromatography-Mass Spectrometry), ICP-MS (Inductively Coupled Plasma-Mass Spectrometry), and fluorescent X-ray analysis. There was a lot of analysis cost and analysis time including pre-processing.

  Therefore, there is a proposal of a method for measuring by chemical ionization of nanoparticles in exhaust gas by laser ionization (Patent Document 1).

An example of a nanoparticle component measuring apparatus for measuring nanoparticles in exhaust gas according to Patent Document 1 is shown in FIG.
As shown in FIG. 11, the nanoparticle component measuring apparatus 100 measures the number of nanoparticles classified by the electrostatic classifier 102 and the electrostatic classifier 102 that classifies the nanoparticle components in the measurement gas 101. A particle number measuring device 103, a heater 105 for heating the classified nanoparticles, and a laser ionization time-of-flight mass spectrometer (mass spectrometer) 106 including a laser device 107 for laser ionizing the heated nanoparticles are provided. For example, nanoparticles discharged from a diesel engine are classified, and polycyclic aromatic hydrocarbons (PAH) are measured with high sensitivity.

JP 2004-219250 A

  Therefore, the appearance of a nanoparticle component measuring apparatus capable of reducing the analysis cost and measuring a trace component in real time and measuring the nanoparticle composition with high accuracy and high sensitivity is eagerly desired.

This invention makes it a subject to provide the nanoparticle component measuring device and method which can measure a nanoparticle composition accurately and with high sensitivity in view of the said problem.

1st invention of this invention for solving the subject mentioned above is a nanoparticle component measuring device which measures the nanoparticle in exhaust gas, Comprising: The electrostatic classifier which classifies the nanoparticle component in measurement gas, the electrostatic classifier charged particle concentration part for concentrating the charged nanoparticles by said such and and a measuring device for measuring the components of the concentrated nanoparticles Rutotomoni, said charged particle concentrator unit, a narrow-diameter cylinder And an outer cylinder composed of a thick diameter cylinder, an inner cylinder provided inside the thick diameter cylinder, and a thin diameter cylinder of the outer cylinder, the first forming an electric field on the nanoparticles. And a second electric field that is arranged outside the narrow diameter inner cylinder and forms a second electric field having a higher voltage than the first electric field for further concentrating the nanoparticles concentrated by the first electric field. The nanoparticle component measuring device is characterized by comprising an electrode 24 .

A second invention is a nanoparticle component measuring device for measuring nanoparticles in exhaust gas, wherein the electrostatic classifier classifies the nanoparticle components in the measurement gas, and the nanoparticles charged by the electrostatic classifier. A charged particle concentrating unit for concentration and a measuring device for measuring the components of the concentrated nanoparticles; and the charged particle concentrating unit includes an outer cylinder having a thin inlet, and an inside of the outer cylinder. An inner cylinder provided; a first electrode disposed within the outer cylinder and forming a first electric field on the nanoparticles; and provided at an outer periphery in the vicinity of an inlet of the inner cylinder, and concentrated by the first electric field. And a second electrode that forms a second electric field having a higher voltage than the first electric field for further concentrating the nanoparticles.

  A third invention is a nanoparticle component measuring apparatus for measuring nanoparticles in exhaust gas, wherein the electrostatic classifier classifies the nanoparticle components in the measurement gas, and the nanoparticles charged by the electrostatic classifier. A charged particle concentrating unit for concentrating, and a measuring device for measuring the components of the concentrated nanoparticles; and the charged particle concentrating unit includes an outer cylinder, and an inner cylinder provided inside the outer cylinder; A net-like first electrode disposed inside the inlet of the inner cylinder and forming a first electric field on the nanoparticles, and a nano-particle provided on the outer periphery near the inlet of the inner cylinder and concentrated by the first electric field. The nanoparticle component measuring apparatus includes a second electrode that forms a second electric field having a higher voltage than the first electric field for further concentrating the particles.

According to a fourth invention, in any one of the first to third inventions, a filter that collects nanoparticles of 1 nm or more on the downstream side of the charged particle concentrating unit, and a heating device that heats the filter It is in the nanoparticle component measuring device characterized by having.

A fifth invention is the nanoparticle component measuring device according to the fourth invention, wherein two or more filters are provided in parallel, and the nanoparticles are continuously measured while switching the flow path. .

A sixth invention is the nanoparticle component measuring device according to the fifth invention, wherein the nanoparticle component measuring device has a flow path that bypasses the parallel filters and continuously measures nanoparticles in real time.

7th invention is the nanoparticle component measuring method which measures the nanoparticle in exhaust gas using any one nanoparticle component measuring apparatus of the 4th thru | or 6, Comprising: In the charged particle concentration part, The nanoparticles are concentrated while relatively reducing the gas component of the gas, and the concentrated nanoparticles are collected by the filter, and the collected nanoparticles are heated and vaporized. It is in the nanoparticle component measuring method characterized by measuring.

  According to the present invention, since the nanoparticles are concentrated and measured, the nanoparticle composition can be measured with high accuracy and high sensitivity.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

A nanoparticle component measuring apparatus according to this embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram of a nanoparticle component measurement apparatus according to an embodiment. FIG. 2 is a schematic view of the charged particle concentration unit. As shown in FIGS. 1 and 2, the nanoparticle component measurement apparatus 10 </ b> A according to the present embodiment is a nanoparticle component measurement apparatus that measures nanoparticles in exhaust gas that is a measurement gas 11. An electrostatic classifier 12 for classifying nanoparticle components, a charged particle concentrator 14 (14-1 to 14-3) for concentrating nanoparticles charged by the electrostatic classifier 12, and components of the concentrated nanoparticles The charged particle concentrating unit 14 includes a first electrode 22 that forms a first electric field on the nanoparticles, and nanoparticles concentrated by the first electric field. And a second electrode 24 for forming a second electric field having a higher voltage than the first electric field to be concentrated.
In FIG. 1, reference numeral 13 denotes a particle number measuring device that measures the number of nanoparticles.

  As shown in FIG. 2, the first charged particle concentrating unit 14-1 of the present embodiment includes an outer cylinder 21 composed of a thin diameter cylinder 21-1 and a thick diameter cylinder 21-2, and a thick diameter cylinder 21-2. The first electrode 22 disposed inside the thin diameter cylinder 21-1 of the outer cylinder 21 and the outside of the narrow diameter cylinder 23-1 of the inner cylinder 23. And a second electrode 24.

Here, the thin diameter cylinder 21-1 of the outer cylinder 21 has a diameter of about 10 mm, and the thin diameter cylinder 23-1 of the inner cylinder 23 has a diameter of about 1 mm.
Then, by applying a voltage of about 500 V to the first electrode 22 and a voltage of about 1 KV to the second electrode 24, the nanoparticles charged by the electrostatic classifier 12 are concentrated in the central portion by the internal electric field. Then, the concentrate 25 is concentrated. The concentration rate of this example is about 100 times.

  In this way, when the nanoparticles classified by the electrostatic classifier 12 are introduced into the vacuum chamber of the mass spectrometer 16 and irradiated with laser light from the laser apparatus 17, the nanoparticle components are ionized and subjected to mass analysis. By utilizing the fact that the nanoparticles taken out from the electrostatic classifier 12 are charged, by providing the charged particle concentrating portion 14 on the downstream side of the electrostatic classifier 12, the concentration rate is about 100 times. It is possible to improve the detection sensitivity of the apparatus.

FIG. 3 shows an example of another charged particle concentrating unit. As shown in FIG. 3, the second charged particle concentration unit 14-2 of the present embodiment includes an outer cylinder 21 having a thin inlet 21 a and an inner cylinder 23 provided in the outer cylinder 21. A first electrode 22 disposed inside the outer cylinder 21 and a second electrode 24 provided on the outer periphery in the vicinity of the inlet of the inner cylinder 23 are provided.
In the present embodiment, since the gas containing the nanoparticles to be introduced is introduced from the thin inlet 21a, the concentrate 25 does not spread but is introduced into the inner cylinder 23 as it is, so that the concentration is performed efficiently.

FIG. 4 shows an example of another charged particle concentrating unit. As shown in FIG. 4, the third charged particle concentrating unit 14-3 of the present embodiment includes an outer cylinder 21 and an inner cylinder 23 provided inside the outer cylinder 21, and an inlet of the inner cylinder 23. A net-like first electrode 22 disposed inside and a second electrode 24 provided on the outer periphery in the vicinity of the inlet of the inner cylinder 23 are provided.
In the present embodiment, the gas containing the nanoparticles to be introduced is introduced from the inlet of the outer cylinder, but the electric field distribution becomes high at the first electrode 22 provided inside the inner cylinder 23, so it cannot be approached, It is divided around the wall surface of the outer cylinder, then concentrated by the second electrode 24, and the concentrate 25 is discharged from the concentration tube 26 provided at the lower end of the outer cylinder 21, so that the concentration is performed efficiently.

  As described above, according to the present invention, by providing the charged particle concentrating unit 14 (14-1 to 14-3), it is possible to concentrate the nanoparticles and perform mass spectrometry with high sensitivity.

FIG. 9 shows an example of the analysis result of the nanoparticles, and FIG. 10 is a partially enlarged view thereof.
As shown in FIGS. 9 and 10, fluorene (molecular number: 166.2), anthracene (molecular number: 178.2), benzo (a) pyrene (molecular number: 252.3), benzo (e) pyrene ( Highly sensitive to polycyclic aromatic hydrocarbons (PAH) such as molecular number: 252.3), benzo (k) fluoranthene (molecular number: 252.3), benzo (ghi) perylene (molecular number: 276.3) It was found that it can be measured.

  Thus, in addition to the minute amount of nano-sized nanoparticles, gasification of components in the mass spectrometer may not be performed completely, and high-sensitivity measurement was difficult with conventional devices. Since the concentration mechanism of the charged particle concentrating unit 14 is provided behind the electrostatic classifier using the fact that the particles taken out from the classifier are charged, the measurement sensitivity can be improved.

A nanoparticle component measuring apparatus according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 5 is a diagram of a nanoparticle component measurement apparatus according to the present embodiment. As shown in FIG. 5, the nanoparticle component measurement apparatus 10B according to the present embodiment is a filter 31 that collects nanoparticles of 1 nm or more on the downstream side of the charged particle concentration unit 14 in the measurement apparatus 10A of FIG. And a heater 15 which is a heating device for heating the filter 31 is provided.

  FIG. 6 is a schematic diagram of the filter 31. The filter is made of stainless steel that can collect mesh-like nanoparticles of 1 nm or more.

When the gas is introduced, the filter 31 is heated by the heater 15 so that the nanoparticle component in the gas is completely vaporized and introduced into the mass spectrometer 16.
In other words, in the past, some of the nanoparticles may be directly introduced into the mass spectrometer 16 without being completely vaporized, and the incomplete measurement is performed by heating the nanoparticles passing through the filter 31 with the heater 15. By vaporizing (for example, 200 ° C.), it is possible to completely vaporize, and the total amount of nanoparticles can be measured, and the reliability of nanoparticle measurement is improved.

  As another method of using the filter 31, the classified measurement gas is allowed to flow through the filter 31 at room temperature for a predetermined time (for example, about 5 minutes), and the nanoparticle component is collected on the filter and heated with a heater (for example, 200 ° C.). ) To vaporize, the collected nanoparticles can be completely vaporized. As a result, the concentration increases by concentration, and the measurement sensitivity of the nanoparticles is greatly improved by completely evaporating the concentration.

  Thus, in addition to the minute amount of nano-sized nanoparticles, gasification of components in the mass spectrometer may not be performed completely, and high-sensitivity measurement was difficult with conventional devices. Utilizing the fact that the particles taken out from the classifier are charged, a filter 31 capable of collecting a particle of 1 nm or more before introducing the vacuum chamber while providing a concentration mechanism of the charged particle concentration unit 14 behind the electrostatic classifier. It is possible to improve the detection sensitivity of the mass spectrometer 16 by installing and completely evaporating.

A nanoparticle component measuring apparatus according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 7 is a diagram of a nanoparticle component measurement apparatus according to the present embodiment. As shown in FIG. 7, the nanoparticle component measurement apparatus 10C according to the present embodiment includes a plurality of nanoparticles that collect nanoparticles of 1 nm or more on the downstream side of the charged particle concentration unit 14 in the measurement apparatus 10B of FIG. Filters 31A, 31B, and 31C are provided in parallel, and a plurality of heaters 15A to 15C that heat the filters 31A to 31C are provided.

And continuous measurement is attained by switching the switching valves 30a-30h of each flow path.
That is, first, when the nanoparticles concentrated by the charged particle concentrating unit 14 are measured by the first filter 31A, the switching valves 30a, 30b, 30e, and 30h are released to flow gas, and the other valves are closed. Keep it. Then, the measurement gas is allowed to flow through the first filter 30A for 5 minutes at room temperature, and then heated for 5 minutes for analysis. Next, the switching valve is switched so that measurement is performed by the second filter 31B. Then, the first filter 31A that has been measured is cleaned with a purge gas to prepare for the next measurement. By sequentially switching the first to third filters 31A to 31C, for example, continuous measurement in an arbitrary range every 10 to 20 minutes is possible.

A nanoparticle component measuring apparatus according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 8 is a diagram of a nanoparticle component measurement apparatus according to the present embodiment. As shown in FIG. 8, the nanoparticle component measurement apparatus 10D according to the present embodiment is provided with a bypass channel 32 having a heater that bypasses the parallel filters 31A to 31C in the measurement apparatus 10C of FIG. 7. If necessary, the switching valves 30i and 30j are opened to continuously measure nanoparticles in real time.

  In the case of collecting for a predetermined time with a filter as shown in FIG. 7, the time delay is measured. However, in the case where the exhaust gas concentration at the present time is always measured, the bypass channel as in this embodiment is used. By providing 32, measurement with the simple concentration function and measurement in real time can be performed in parallel.

  As described above, the nanoparticle component measurement apparatus according to the present invention can reduce the analysis cost and improve the sensitivity of a trace component.

1 is a schematic diagram of a nanoparticle component measurement apparatus according to Example 1. FIG. It is the schematic of a charged particle concentration part. It is the schematic of another charged particle concentration part. It is the schematic of another charged particle concentration part. 3 is a schematic diagram of a nanoparticle component measurement apparatus according to Example 2. FIG. It is the schematic of a filter. 6 is a schematic view of a nanoparticle component measurement apparatus according to Example 3. FIG. It is the schematic of the nanoparticle component measuring device which concerns on Example 4. FIG. It is a measurement figure of an example of the analysis result of a nanoparticle. FIG. 10 is a partially enlarged view of FIG. 9. It is the schematic of the conventional nanoparticle component measuring apparatus.

10A to 10C Nanoparticle component measuring device 11 Measuring gas 12 Electrostatic classifier 13 Particle number measuring device 14 (14-1 to 14-3) Charged particle concentrator 15 Heater 16 Mass spectrometer 21 Outer cylinder 22 First electrode 23 Inner cylinder 24 Second electrode 25 Concentrate

Claims (7)

A nanoparticle component measuring device for measuring nanoparticles in exhaust gas,
An electrostatic classifier that classifies the nanoparticle components in the measurement gas;
A charged particle concentrating unit for concentrating nanoparticles charged by the electrostatic classifier;
Rutotomoni such by and a measuring device for measuring the components of the nanoparticles the concentrated,
The charged particle concentrating part is
An outer cylinder composed of a thin diameter cylinder and a thick diameter cylinder;
An inner cylinder provided inside the thick-diameter cylinder;
A first electrode disposed in a thin diameter cylinder of the outer cylinder and forming a first electric field on the nanoparticles;
A second electrode 24 arranged outside the narrow cylinder of the inner cylinder and forming a second electric field having a higher voltage than the first electric field for further concentrating the nanoparticles concentrated by the first electric field. The nanoparticle component measuring device characterized by comprising. A nanoparticle component measuring device for measuring nanoparticles in exhaust gas,
  An electrostatic classifier that classifies the nanoparticle components in the measurement gas;
  A charged particle concentrating unit for concentrating nanoparticles charged by the electrostatic classifier;
  Comprising a measuring device for measuring the components of the concentrated nanoparticles,
  The charged particle concentrating part is
  An outer cylinder having a thin inlet,
  An inner cylinder provided inside the outer cylinder;
  A first electrode disposed inside the outer cylinder and forming a first electric field on the nanoparticles;
  A second electrode that is provided near the inlet of the inner cylinder and that forms a second electric field having a higher voltage than the first electric field for further concentrating the nanoparticles concentrated by the first electric field. A nanoparticle component measuring device. A nanoparticle component measuring device for measuring nanoparticles in exhaust gas,
  An electrostatic classifier that classifies the nanoparticle components in the measurement gas;
  A charged particle concentrating unit for concentrating nanoparticles charged by the electrostatic classifier;
  Comprising a measuring device for measuring the components of the concentrated nanoparticles,
  The charged particle concentrating part is
  An outer cylinder,
  An inner cylinder provided inside the outer cylinder;
  A net-like first electrode disposed inside the inlet of the inner cylinder and forming a first electric field on the nanoparticles;
  A second electrode that is provided near the inlet of the inner cylinder and that forms a second electric field having a higher voltage than the first electric field for further concentrating the nanoparticles concentrated by the first electric field. A nanoparticle component measuring device. In any one of Claims 1 thru | or 3 ,
A nanoparticle component measuring device comprising a filter that collects nanoparticles of 1 nm or more and a heating device that heats the filter on the downstream side of the charged particle concentrating unit. In claim 4 ,
A nanoparticle component measuring apparatus, wherein two or more filters are provided in parallel, and the nanoparticles are continuously measured while switching the flow path. In claim 5 ,
A nanoparticle component measuring apparatus having a flow path that bypasses the parallel filters and continuously measuring nanoparticles in real time. A nanoparticle component measurement method for measuring nanoparticles in exhaust gas using the nanoparticle component measurement device according to any one of claims 4 to 6,
  In the charged particle concentration unit, the nanoparticles are concentrated while relatively reducing the gas component in the exhaust gas,
  A method for measuring a nanoparticle component, comprising collecting the concentrated nanoparticle by the filter, heating and vaporizing the collected nanoparticle, and measuring the component of the nanoparticle with the measuring device.

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