JP2010085353A - Particulate measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure a slight quantity of minute suspended particulates efficiently with high sensitivity. <P>SOLUTION: This particulate measuring instrument includes: a particulate trapping/processing means equipped with a route for introducing particulates suspended in a measurement area and made by disposing a particulate trap filter made of a porous body in the route; a particulate accumulating means for accumulating the particulates in a prescribed small area on the trap filter; a sensitivity intensifying treatment means for adding a sensitivity intensifying agent to the particulates accumulated in the prescribed small area for intensifying their spectral sensitivity; and a spectral processing means for performing required spectral separation as to the particulates with their spectral sensitivity intensified. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a particle measuring apparatus for measuring suspended particles.

  For example, CNT as a floating fine particle has a shape in which a graphene sheet in which carbon atoms are arranged in a hexagonal shape is wound in a cylindrical shape, has a substantially uniform diameter shape in the length direction, and has an aspect ratio that is a ratio of length to diameter. It is used in various applications such as semiconductor materials, conductive materials, field electron emission sources, and strength enhancing materials because it is large and fine in diameter, has high mechanical strength, and becomes a semiconductor or metal (Patent Document 1). reference).

In addition to such CNTs, it is preferable to take safety measures against exposure of dust to the human body, for example, in the manufacturing process of fine particles on the order of nm, for example, in the production process. However, since the fine particles are fine and exist in minute amounts, they are highly efficient and highly sensitive in the air or in a liquid state, and in addition to their type, form, and floating state. It is difficult to realize an apparatus capable of performing measurement in accordance with appropriate conditions.
JP 2001-303250 A

  The present invention is intended to provide a fine particle measuring apparatus capable of measuring suspended fine particles with high efficiency and high sensitivity without depending on the kind of fine particles and regardless of the form of the fine particles. is there.

  A particle measuring apparatus according to a first aspect of the present invention includes a particle trap processing unit including a path for introducing particles floating in a measurement area, and a particle trap filter formed of a porous body in the path, and the particle A sensitizing processing means for adding a sensitizing material for sensitizing the spectral sensitivity to the fine particles on the trap filter; and a spectral processing means for performing a required spectral processing on the fine particles having the spectral sensitivity sensitized. It is characterized by this.

  A particle measuring apparatus according to a second aspect of the present invention includes a particle trap processing unit including a path for introducing particles floating in a measurement area, and a particle trap filter formed of a porous body in the path, and the particle Fine particle collecting means for collecting the fine particles in a predetermined small area on the trap filter, sensitization processing means for adding a sensitizing material for sensitizing spectral sensitivity to the fine particles accumulated in the predetermined small area, and the spectral sensitivity. Spectral processing means for performing required spectral processing on the sensitized fine particles.

  The first and second aspects of the present invention are not limited to the floating form of the fine particles, and the floating place may be in the air or in the liquid.

  The first and second aspects of the present invention are not limited to the type of fine particles. Examples of the fine particles include, for example, carbon-based fine particles floating in the air and liquid, organic-containing fine particles, and fine particles composed of an inorganic substance. Carbon-based fine particles include, for example, CNT.

  The porous body is not particularly limited, but a polymer resin or ceramic porous body is preferably used, and more preferably a porous body such as resin, alumina, silica gel, and porous glass. . In particular, porous glass has the advantage that it can be easily molded into various shapes and the pore diameter is almost uniform, and the shape can be easily formed when it is detachably mounted in the predetermined path. Since the pore diameter is uniform, it is suitable for controlling trapping of fine particles.

  The fine particle accumulation processing means is not particularly limited, but for example, the effect of re-aggregating fine particles by redispersing the fine particles on the solvent surface and evaporating the solvent, and further light emission of fine particles floating in the solvent. It is effective to promote the concentration of fine particles by accumulating droplets by the action of pressure, the unevenness of the substrate and the affinity on the substrate.

  When fine particles are accumulated in a predetermined small area by the fine particle accumulation processing means, the fine particle concentration increases, which is preferable for fine particle measurement. In addition, the collected fine particles are sensitized, and the sensitized fine particles are measured by spectroscopic means. Therefore, even if the amount of suspended fine particles is small, the minute amount of fine particles can be efficiently measured. it can.

  The sensitizing treatment means is not particularly limited, and can be constituted by means for enhancing the spectral sensitivity of the fine particles by adding a solvent containing a sensitizer, for example.

  The sensitizing treatment means, for example, adds a solvent containing metal nanoparticles as a sensitizer for enhancing spectral sensitivity, and irradiates the metal nanoparticles with light to cause surface plasmon resonance in the metal nanoparticles. Thus, it can be constituted by means for enhancing the surface of the scattered light in the fine particles on the sample.

  The spectroscopic processing means is not particularly limited. For example, the spectroscopic processing means is capable of measuring and processing any of absorption peak, reflection peak, fluorescence peak, and scattering peak by spectroscopic analysis, and identifying the constituent components of the fine particles by these. Anything that can do.

  In the first aspect of the present invention, since the fine particles are trapped by the trap processing means, and the fine particles on the trapped sample are sensitized by the sensitizing processing means and then spectrally processed, the amount of the suspended fine particles is very small. However, it becomes possible to measure with high measurement efficiency.

  In the second aspect of the present invention, the fine particles are trapped by the trap processing means, the fine particles on the trapped sample are accumulated in a predetermined small area by the fine particle accumulation processing means, and further sensitized by the sensitization processing means. Since it is processed, it becomes possible to measure the suspended fine particles with high measurement efficiency even if the amount is small.

  According to the present invention, even if the amount of suspended fine particles is small, it can be accurately measured with high sensitivity.

  Hereinafter, a particle measuring apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the embodiment, CNT among the fine particles is a measurement target, but the fine particles are not limited to this CNT. Further, although the spectral form is also described by applying to Raman spectroscopy, the spectroscopy is not limited to Raman spectroscopy.

  FIG. 1 shows processing means of the fine particle measuring apparatus. As shown in FIG. 1, this fine particle measuring apparatus includes a fine particle trap processing means for trapping fine particles such as CNT, a fine particle collection processing means for collecting fine particles trapped by the fine particle trap processing means in a certain small area, and the fine particles. Raman sensitizing treatment means for adding metal nano-particles, which are Raman sensitizing materials for sensitizing the Raman spectral sensitivity to the fine particles accumulated by the accumulation processing means, and fine particles whose Raman spectral sensitivity is sensitized by the Raman sensitizing processing means. And Raman spectroscopy processing means for quantitatively measuring the amount of suspended particulates by performing Raman spectroscopy.

  Referring to FIG. 2, the particulate trap processing means will be described. Reference numeral 1 denotes a trap apparatus as the particulate trap processing means. The trap device 1 is arranged at an appropriate position in the measurement area 3 and traps (captures or captures) the CNTs 9 a floating in the measurement area 3. It is assumed that the measurement area 3 is an area that is a clean environment in which, for example, workers who handle the CNTs 9a are present, and the CNTs 9a are mainly floating in the measurement area 3 due to the above work and the like. Further, it is assumed that various fine particles 9b other than the CNT 9a are floating.

  The trap device 1 includes at least a cylindrical filter case 5 and a trap filter 7 in order to trap the CNTs 9a and various fine particles 9b. The filter case 5 includes a cylindrical large-diameter portion 5a at the top of the case, a cylindrical small-diameter portion 5b at the bottom of the case, and a large-diameter and small-diameter both portions 5a and 5b. The trap filter 7 is detachably mounted inside the small diameter portion 5b.

  The CNTs 9a and other fine particles 9b floating in the measurement area 3 are introduced into the large-diameter portion 5a of the filter case 5 of the trap device 1 and drop by their own weight in the small-diameter portion 5b below the case. It is trapped by the CNT trap filter 7 attached to.

  The structure of the trap filter 7 will be described with reference to FIG. 3A is a plan view schematically showing a part of the SEM photograph of the trap filter 7, and FIG. 3B is a cross-sectional view taken along the line AA of FIG. 3A.

  The trap filter 7 is composed of a porous body having a large number of pores having a pore diameter through which the CNT 9a or the like cannot pass, in the embodiment, porous glass. Examples of the method for producing the porous glass include a method using phase separation of glass, a method using a sol-gel method, and a method using sintering of uniform fine particles. The porous glass shown in FIG. 3 is produced by a method based on glass phase separation.

In FIG. 3A, the portion displayed in black is a pore portion, and the portion displayed in white is a porous glass portion. The pore diameter of this porous glass is distributed between 6 nm and 100 nm. This porous glass is a base glass (borosilicate glass) mainly composed of SiO ₂ (50-70 wt%): B ₂ O ₃ (20-40 wt%): Na ₂ O (5-15 wt%). ) At a temperature not lower than the glass transition point and not higher than the softening point (usually 500 ° C. to 650 ° C.), and then etched by acid and alkali. The porous glass produced in this way has a quartz glass sponge structure. Thus, the porous glass of the embodiment is a high silicate type porous glass made as described above. This porous glass has a large number of pores, and the pore diameter can be controlled by the composition of the base glass, the heat treatment conditions for phase separation, and the like.

  The filter case 5 of the trap device 1 has a large diameter at the top and a small diameter at the bottom, and the trap filter 7 is mounted on the small diameter portion 5b. Therefore, the filter area of the trap filter 7 is the large diameter at the top of the filter case 5. This is smaller than the opening area of the portion 5a, so that the CNTs 9a and other fine particles 9b can be trapped on the filter surface and concentrated.

  The CNTs 9a and other fine particles 9b are introduced into the filter case 5 of the CNT trap filter 7 by their own weights. It becomes easy to introduce into the filter case 5.

  The trap filter 7 traps the CNTs 9a and other fine particles 9b over a wide range of the entire filter surface. Therefore, the amount of the CNTs 9a and other fine particles 9b may be insufficient for quantification by Raman spectroscopy. Therefore, in order to accumulate the CNTs 9a and other fine particles 9b in a predetermined small area on the filter surface of the trap filter 7, the CNTs 9a and other fine particles 9b are trapped by the fine particle accumulation processing means which is the next processing means shown in FIG. The filter 7 is accumulated in a certain small area suitable for Raman spectral processing.

  The fine particle accumulation processing means will be described with reference to FIG. First, as shown in FIG. 4A, CNTs 9a and other fine particles 9b are scattered and trapped on the trap filter 7 over a wide range of the entire filter surface by the fine particle trap processing means.

  Then, as shown in FIG. 4B, ethanol 11 is dropped onto the trap filter 7 as an example of a dispersion medium using a dropping jig 13. CNTs 9a and other fine particles 9b on the trap filter 7 are dispersed in the dropped ethanol 11a.

  Next, as shown in FIG. 4C, light irradiation 15 is performed on the CNTs 9a and other fine particles 9b on the trap filter 7, and the CNTs 9a and other fine particles 9b are reduced to a certain size by the mechanical action of the light irradiation 15. Accumulate in the area. For example, in the experiment of the present applicant, assuming that the CNTs 9a and other fine particles 9b are scattered in a circle having a diameter of 10 mm, the CNTs 9a and other fine particles 9b are accumulated in a circle having a diameter of 0.1 mm to increase 10,000 times. It was possible to concentrate. This mechanical action is due to the light radiation pressure generated when the CNT 9 a on the trap filter 7 and other fine particles 9 b are irradiated with light 15. The action direction of the light radiation pressure is manipulated to accumulate the CNTs 9a and other fine particles 9b in a certain small area as shown in FIG. The accumulation action of the CNTs 9a and other fine particles 9b by the light radiation pressure will be described. First, light propagating through the ethanol solvent 11a by the light irradiation 15 into the ethanol solvent 11a on the trap filter 7 is a medium having a different refractive index. When entering a certain CNT 9a or other fine particles 9b, the direction of light changes due to refraction. This change acts as a light radiation pressure of reaction force on the CNT 9a and other fine particles 9b. The direction in which the light radiation pressure works is determined by the refractive index relationship between the ethanol solvent 11a and the CNTs 9a and other fine particles 9b. By this light radiation pressure control, the CNTs 9a and other fine particles 9b can be accumulated in a certain small area.

  When the CNTs 9a and other fine particles 9b accumulate in a certain small area, the ethanol solvent 11a is vaporized as shown in FIG. In this way, the CNTs 9a and other fine particles 9b are accumulated on the predetermined small area of the trap filter 7 and concentrated.

  Next, a process of adding a Raman sensitizing material for sensitizing the Raman spectral sensitivity to the CNTs 9a and other fine particles 9b accumulated in a certain small area by the fine particle accumulation processing means is performed. The Raman sensitizing processing means for performing this Raman sensitizing processing will be described with reference to FIG. 5. As shown in FIG. 5 (a), the Raman sensitizing processing includes metal ultrafine particles (metal nanoparticle) 17a such as gold and silver. The photosensitive material liquid 17 is dropped onto the CNT 9a and other fine particles 9b accumulated on the trap filter 7 as shown in FIG.

  When the metal nanoparticles 17a are irradiated with light 21 as shown in FIG. 5B, surface plasmon resonance (SPR) occurs in the metal nanoparticles 17a.

  In this surface plasmon resonance, when the surface of the metal nanoparticle 17a is irradiated with light 21, free electrons on the surface of the metal nanoparticle 17a are excited, and the free electrons vibrate in the group 17b as shown in FIG. 5C. As a result, surface plasmon waves are generated and a strong electric field is generated.

  In this case, the CNTs 9a and other fine particles 9b also vibrate with the group 17b. A solution containing the metal nanoparticles 17a such as silver is dropped on the accumulated CNTs 9a and other particles 9b in this manner, and light irradiation 21 is performed to cause plasmon resonance on the surface of the metal nanoparticles 17a. Scattered light intensity can be enhanced (SERS :).

  Next, Raman spectroscopy is performed on the CNT 9a and other fine particles 9b whose Raman scattered light intensity is enhanced by the Raman sensitizing processing means on the trap filter 7. For Raman spectroscopy, when light of a certain wavelength is irradiated on a substance, in addition to light of the same wavelength as that light (Rayleigh light), a small amount of light (Raman light) that is slightly shifted in wavelength is scattered, but its wavelength This shift is peculiar to the substance, and in Raman spectroscopy, the Raman spectrum of the scattered light is measured by light irradiation 21.

  This Raman spectroscopy processing means will be described with reference to FIG. In FIG. 6, a laser irradiation light 25 from a laser light source 23 is applied to a dichroic filter 27 provided with an inclination of 45 degrees with respect to the laser irradiation light 25. The dichroic filter 27 reflects light of a specific wavelength of the laser irradiation light 25, but transmits all other wavelength light. Therefore, the laser irradiation light 25 is reflected by 90 degrees by the dichroic filter 27 and is reflected by the objective lens 29 on the CNT 9a and others. The light is condensed on the fine particles 9b. Then, light of various wavelengths diffused from the CNT 9a and other fine particles 9b is collected by the objective lens 29, passes through the dichroic filter 27, and is detected from the objective lens 31 by the CCD detector 33 as laser reflected light 28. . In this case, the dichroic filter 27 passes the spectrum of Raman light shifted to another wavelength except for Rayleigh scattered light reflected at the same specific wavelength as the laser irradiation light 25. The signal detected by the CCD detector 33 is analyzed by the analysis unit 35, and the analysis state is displayed on the monitor screen of the monitor device 37.

FIG. 7 shows the spectrum of Raman scattered light (Raman spectrum) on the monitor screen of the monitor device 37. This Raman spectrum is represented by a graph in which the vertical axis represents the Raman scattered light intensity and the horizontal axis represents the Raman shift (unit: wave number, cm ⁻¹ ). In this Raman spectrum, a peak found in graphite having a high crystallinity called G peak appears near 1585 (cm ⁻¹ ), and a defect density existing in a graphite crystal called D peak appears near 1380 (cm ⁻¹ ). Peak appears. In the embodiment, the laser irradiation light 25 is applied to the CNTs 9a and other fine particles 9b that are accumulated on the trap filter 7 and subjected to Raman sensitization, and Raman scattering is performed among the scattered light on the CNTs 9a and other fine particles 9b. By measuring light, it is possible to measure the amount of CNTs 9a and other fine particles 9b on the trap filter 7.

  Then, the amount of CNT 9a and other fine particles 9b floating in the measurement area 3 can be determined from the measured amount of the CNT 9a and other fine particles 9b. Control such as cleaning in the measurement area 3 is performed so that the floating amount of the liquid crystal becomes a certain amount or less.

  FIG. 8 shows a particle measuring apparatus 39 for carrying out the measuring method of the embodiment, and includes a hardware unit 39a and a software unit 39b. The hardware unit 39a accumulates the particulate trap processing apparatus 41 for trapping particulates, the particulate collection processing apparatus 43 that accumulates particulates trapped on the particulate trap filter 7 in a certain small area, and the particulate trap filter 7. A Raman sensitizing processing device 45 for adding a Raman sensitizing material that sensitizes the Raman spectral sensitivity to the fine particles, a Raman spectral processing device 47 for performing Raman spectroscopy on the fine particles whose Raman spectral sensitivity has been sensitized, and Raman spectroscopy. And a monitor device 49 for monitoring the measurement result of the processing device 47.

  The particulate trap processing apparatus 41 has the same configuration as the particulate trap apparatus 1 described with reference to FIGS. 2 and 3, but when the trap target is particulates, a trap filter suitable for the particulate trap is set. The trap filter can be provided in the device 41 so as to be detachable or replaceable.

  The fine particle accumulation processing device 43 is a device that accumulates the fine particles described in FIG. 4 with light radiation pressure, a dropping jig that drops a solvent such as ethanol on the fine particles, and a light irradiation device that irradiates the fine particles in the solvent with light. And a solvent vaporizer.

  The Raman sensitizing processing device 45 is a device for enhancing the Raman spectral sensitivity of the fine particles described in FIG. 5, a dropping jig for dropping a solvent such as ethanol on the fine particles, and a light irradiation device for irradiating the fine particles in the solvent with light. And.

  The Raman spectroscopic processing device 47 is the device described with reference to FIG.

  The software unit 39b includes a CPU (processor) 49, a ROM 51, a RAM 53, an operation unit 55, a trap processing device driver 57, a particle accumulation processing device driver 59, a Raman sensitizing processing device driver 61, and a Raman spectral processing device driver 63. .

  The CPU 49 controls the entire particle measuring device 39. The ROM 51 stores system programs, application programs for the respective processing devices, and the like. The RAM 53 is used for work of the CPU 49 or the like. The operation unit 55 is a key or the like disposed on the device panel and operated by the user.

  The trap processing device driver 57 drives the particulate trap processing device 41. When a lid is provided at the upper opening of the particulate trap device 1, the trap processing device driver 57 opens and closes the lid, and attaches / detaches the particulate trap filter 7. When provided, the mechanism is driven.

  The particulate collection processing device driver 59 drives a dropping device, a light irradiation device, a particulate trap filter setting device, etc. in the particulate collection processing device 43.

  The Raman sensitizing processing device driver 61 drives a dropping device, a light irradiation device, and the like in the Raman sensitizing processing device 45.

  The Raman spectroscopic processing device driver 63 drives and controls the laser light source, CCD detector, analysis unit, and the like in the Raman spectroscopic processing device 47.

  The monitor device driver 65 controls the display of the Raman spectrum on the monitor screen in the monitor device 49.

  As described above, in the present embodiment, even if the amount of fine particles floating in the air is very small, it can be accurately quantified by Raman spectroscopy.

FIG. 1 is a diagram conceptually showing each means of the particle measuring apparatus according to the embodiment of the present invention. FIG. 2 is a view showing the particulate trap processing means. 3A is a plan view of the particulate trap filter, and FIG. 3B is a cross-sectional view of the particulate trap filter. FIG. 4 is a diagram for explaining the particle accumulation processing means. FIG. 5 is a diagram for explaining the Raman sensitizing material for the accumulated fine particles. FIG. 5 is a diagram showing a schematic configuration of the Raman spectroscopic processing means. FIG. 7 shows a Raman spectrum on the monitor screen. FIG. 8 is a diagram showing the configuration of the particle measuring apparatus.

Explanation of symbols

1 particulate trap device 3 measurement area 7 particulate trap filter

Claims (3)

A fine particle trap processing means having a path for introducing fine particles floating in the measurement area, and a fine particle trap filter made of a porous material in the path;
Sensitization treatment means for adding a sensitizing material for sensitizing the spectral sensitivity to the fine particles on the fine particle trap filter;
Spectral processing means for performing the required spectral processing on the fine particles sensitized with the spectral sensitivity;
A fine particle measuring apparatus comprising: A fine particle trap processing means having a path for introducing fine particles floating in the measurement area, and a fine particle trap filter made of a porous material in the path;
Fine particle collecting means for collecting the fine particles in a predetermined small area on the fine particle trap filter;
Sensitization processing means for adding a sensitizer for increasing spectral sensitivity to the fine particles accumulated in the predetermined small area; and
Spectral processing means for performing the required spectral processing on the fine particles sensitized with the spectral sensitivity;
A fine particle measuring apparatus comprising:   The apparatus according to claim 1, wherein the porous body is made of porous glass.

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