JP2008107092A - Passive collector of gaseous specimen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a passive collector of a gaseous specimen capable of using absorbent impregnated filter paper as a collector of the gaseous specimen, reducing the effect on the collection amount of the gaseous specimen due to wind velocity and capable of obtaining the collection amount of the gaseous specimen required in analysis in an exposure time from several times to about one day. <P>SOLUTION: The passive collector of the gaseous specimen is constituted by laminating and fixing the collector of the gaseous specimen and a diffusion member, through which a gas molecule passes, on a support by a molecular diffusion theory in this order. The collector is filter paper impregnated with an absorbent for the gaseous specimen and the diffusion member is a planar porous member obtained by sintering, fusing and molding resin particles. In the diffusion member, the gaps between the sintered and fused resin particles are connected in the thickness direction of the diffusion member as continuous perforations. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a passive collector that passively collects gaseous analytes in the air, such as gaseous harmful pollutants.

  In recent years, passive collectors using molecular diffusion (also called passive samplers, diffusion samplers, etc.) have been widely used for collecting gaseous harmful pollutants in the atmosphere or indoor air. The passive collector is basically composed of a diffusion layer and an absorption layer, and generates a concentration gradient of a gaseous test substance between the test air and the absorption layer surface via the diffusion layer, and Fick's diffusion law. The gaseous test substance that moves according to the above is collected quantitatively. Such passive collectors do not require power, are small, light and easy to carry, and can collect gaseous hazardous pollutants in the atmosphere or indoor air with simple operation, so that It is also used for measuring concentration and measuring indoor air quality in ordinary houses.

The type and shape of the absorption layer are appropriately selected according to the type of the gaseous test substance. Conventionally, in such a passive collector, when collecting an acidic substance / basic substance in the atmosphere as a gaseous test substance, it is inexpensive, small and lightweight, a gaseous test substance Filter paper impregnated with an appropriate absorbent (hereinafter referred to as "absorbent-impregnated filter paper") because it is easy to prepare an absorbent layer according to the above, and because the absorbent layer is solid, it is easy to handle. ) Have been used as an absorbing layer. For example, for collecting nitrogen dioxide (NO ₂ ), sulfur dioxide (SO ₂ ), hydrogen chloride (HCl), triethanolamine-impregnated filter paper, for collecting hydrogen sulfide (H ₂ S), silver nitrate-impregnated filter paper, For collecting organic acids such as formic acid and acetic acid, a potassium hydroxide aqueous solution impregnated filter paper is used as an absorbing layer, and for collecting ammonia (NH ₃ ), boric acid impregnated filter paper is used as an absorbing layer. As the filter paper, generally, a nitrocellulose quantitative filter paper, a qualitative filter paper, a chromatographic filter paper, or the like is suitably used.

The shape of the diffusion layer is appropriately selected according to the shape of the absorption layer. When an absorbent-impregnated filter paper is used as an absorbent layer, Palmes tube (Non-Patent Document 1) using a cylinder as the diffusion layer is best known. In addition, a passive collector using a water-repellent filter paper (Patent Document 1), a resin film (Patent Document 2), a resin porous plug (Ogawa Sampler manufactured by Ogawa Shokai, HandySONO _x manufactured by Green Blue) is known. It has been.

However, when Palmes tube using a cylinder is used as the diffusion layer, it is strongly affected by the wind speed in the exposure environment, the effective diffusion length is reduced due to the generation of vortex flow at the open end of the cylinder, and the gaseous test substance is excessive. Tend to be collected. In addition, since the collection speed is slow, long-term exposure of about 1 week to 1 month is required for analysis and quantification with sufficient sensitivity, and when the gaseous test substance is NO ₂ , diffusion is required. The positive error due to NO ₂ caused by the reaction between ozone and nitric oxide in the layer cannot be ignored.

  When water-repellent filter paper is used as the diffusion layer, the gap that becomes the path for the gaseous test substance is narrow, and as a result, in the diffusion process, the interaction between the water-repellent filter paper and the gaseous test substance occurs. When the gaseous test substance has high hydrophilicity, an error in absorption due to humidity fluctuations occurs.

  When a resin film is used as the diffusion layer, one having a thickness of 0.5 mm or less is usually used, and since it exhibits a high mass transfer coefficient, the collection time can be greatly reduced. Since it is as thin as 0.5 mm or less, it is easily affected by the wind speed in the exposure environment. Similarly, when a resin porous plug is used as the diffusion layer, the influence of the wind speed is exponentially affected.

  Further, Patent Documents 3 to 6 describe passive sampling adsorption devices in which a container or filter made of a porous material obtained by sintering or welding resin particles is filled with an adsorbent. Describes a passive sampler in which a filter formed and molded by sintering or welding resin particles is coated with an adsorbent.

However, since the devices described in Patent Documents 3 to 6 are passive sampling adsorption devices that use particulate adsorbents (activated carbon, zeolite, alumina, etc.) as an absorption layer, the adsorbents are contained in a container made of a porous material. The amount of collection varies due to movement of. In addition, the adsorbent in the container may be damaged due to vibration or the like, and the damaged adsorbent fragments may clog the container gap, and conversely, the damaged adsorbent fragments may pass through the container gap. There is a risk of leakage outside the container.
In addition, since the passive sampler described in Patent Document 7 has a structure in which an adsorbent is coated on a filter, the passive sampler is affected by the wind speed in the exposure environment as in the case of using a resin film or a resin porous plug as a diffusion layer. Cheap. Moreover, it takes time to analyze the adsorbed gaseous test substance, and the filter coated with the adsorbent is usually not reusable and is disposable.

Palmes, E .; D. Gunnison, A .; F. , Dimattio, J .; and Tomczzyk, C.I. 1976. Personal sampler for nitrogen dioxide, Am. Ind. Hyg. Assoc. J. et al. 37, 570-577. Japanese Utility Model Publication No. 58-30220 Japanese Patent No. 3230150 Japanese Patent Laid-Open No. 2001-4609 JP 2001-183263 A JP 2001-2042 A JP 2002-357517 A JP 2004-191120 A

  In order to solve the above-described problems of the prior art, the problem of the present invention is that an absorbent-impregnated filter paper can be used as a collector of a gaseous test substance, and the air speed depends on the amount of the collected gaseous test substance. To provide a passive collector of a gaseous test substance that has little influence and can obtain a collection amount necessary for analysis in an exposure time of several hours to about one day.

  In order to solve the above problems, the present inventors have studied a passive collector utilizing the molecular diffusion principle of gas, and as a diffuser, obtained by sintering or welding resin particles. By using a planar porous body having pores, using an adsorbent-impregnated filter paper as a collector for a gaseous test substance, and laminating and fixing the planar porous body and the adsorbent-impregnated filter paper, It has been found that a passive collector having a low trapping effect and a high trapping speed can be obtained.

That is, in the present invention, a collector of a gaseous test substance and a diffuser through which gas molecules pass on the principle of molecular diffusion are laminated and fixed in this order on the support,
The collector is a filter paper impregnated with an absorbent of the gaseous test substance;
The diffuser is a planar porous body obtained by sintering or welding resin particles and molding,
In the diffuser, there is provided a passive collector for a gaseous test substance, wherein the gap between the sintered or welded resin particles is connected as a continuous hole in the thickness direction of the diffuser. .

  In the passive collector of the present invention, it is preferable that the resin particles are made of at least one resin selected from the group consisting of polyethylene, polypropylene, fluororesin and polyester.

  In the passive collector of the present invention, the diffuser has a thickness of 0.5 to 2.0 mm, a pore diameter of the continuous hole of 10 to 100 μm, and a porosity of 20 to 75%. Preferably there is.

  In the passive collector of the present invention, it is preferable that the support has a circular planar shape at a portion where the collector and the diffuser are stacked and fixed.

According to the present invention, passive collection of a gaseous test substance that is less affected by the wind speed on the collection volume and can obtain a collection volume necessary for analysis within an exposure time of several hours to about a day. Can be provided and used for passive monitoring of gaseous hazardous pollutants in the atmosphere or indoors.
Since the passive collector of the present invention uses an absorbent-impregnated filter paper as a collector of a gaseous test substance, it is inexpensive, small and light, and a collector according to the gaseous test substance. It is easy to prepare the filter, and by exchanging only the absorbent-impregnated filter paper, it is possible to quickly collect another gaseous test substance. Moreover, it can apply to the analysis of the collected gaseous test substance, without changing the method widely used conventionally.

  FIG. 1 shows an example of an embodiment of the passive collector of the present invention. Fig.1 (a) is a side view of the passive collector of this invention, and the end view which looked at the passive collector from the right side is shown on the right side of the drawing. FIG.1 (b) is a perspective view of a passive collector. For ease of understanding, the passive collector is shown with its components disassembled.

A passive collector shown in FIGS. 1A and 1B includes a support 1, a collector 2 of a gaseous test substance, a diffuser 3 through which gas molecules pass on the principle of molecular diffusion, and a stopper 4. Consists of.
The support 1 is cylindrical. The collector 2 is a filter paper (absorbent-impregnated filter paper) impregnated with a desired absorbent according to the gaseous test substance, and has a circular planar shape. As will be described in detail later, the diffusing body 3 is a planar porous body having continuous pores obtained by sintering or welding and molding resin particles, and the outer shape thereof is a disc shape. The stopper 4 is open at both ends and has a substantially cylindrical shape. In addition, since the stopper 4 locks and fixes the collector 2 and the diffuser 3 when using a passive collector, the diameter of the opening (the opening on the right end of the drawing) far from the support 1 is fixed. Is smaller than the inner diameter of the cylinder and the diameter of the left end (having a small diameter portion).

  When the passive collector is used, the collector 2 and the diffuser 3 are installed on the support 1, more specifically, on one end surface of the cylindrical support 1 in a state of being laminated in this order. It is fixed using the stopper 4. In this state, when the passive collector is left in the air for a certain period of time, gaseous test substances such as gaseous harmful pollutants in the atmosphere pass through the continuous pores of the diffuser 3 on the principle of molecular diffusion. Then, it is passively collected by the collector 2.

Each component of the passive collector of this application is demonstrated more concretely.
The shape of the support 1 is particularly limited as long as the collector 2 and the diffuser 3 can be laminated and fixed in this order so that the collector 2 does not come into direct contact with the test air such as air or room air. It is not limited, For example, a cylindrical shape, columnar shape, and board shape may be sufficient. However, since the planar shape of the adsorbent-impregnated filter paper used as the collector 2 is usually circular, in order to minimize the collection unevenness of the gaseous test substance, the collector 2 and the diffuser in the support 1 It is preferable that the planar shape of the part (end surface) where 3 is laminated and fixed is circular. Therefore, like the support 1 shown in FIGS. 1A and 1B, the cylindrical support 1 in which the planar shape of the portion (end face) where the collector 2 and the diffuser 3 are stacked and fixed is circular. It is preferable. However, since the planar shape of the part (end surface) where the collector 2 and the diffuser 3 are laminated and fixed may be circular, a disk-shaped support can also be used. However, from the viewpoint of handleability, the shape of the support is preferably a columnar shape.

Although the dimension of the support body 1 is not specifically limited, It is required that the collector 2 and the diffuser 3 be dimensions that can be laminated and fixed in this order. Accordingly, in the case of the support 1 shown in FIGS. 1A and 1B, the diameter of the cylinder is the diameter of the absorbent-impregnated filter paper used as the collector 2 and the disk-like planar porous used as the diffuser 3. It must be equal to or larger than the diameter of the mass.
The material of the support 1 is not particularly limited as long as it has no significant adsorptivity or reactivity with respect to the gaseous test substance and the absorbent used in the collector 2, but polyethylene, polypropylene, fluororesin, polyester ABS resin, glass, quartz or stainless steel is preferable.

  The filter paper used as the collecting body 2 can be used without any particular change in specifications from those conventionally used as the collecting body. Specifically, generally, nitrocellulose quantitative filter paper, qualitative filter paper, chromatography filter paper, and the like are preferably used.

The diameter of the filter paper is 5 mm to 100 mm. Passive collectors are one of the advantages over dynamic collectors (active samplers) that use pumps because of their small size, light weight, and easy handling, and the diameter of the filter paper is as described above. Within the range, the handleability is good, and the resistance when the gaseous test substance passes through the principle of molecular diffusion is small. Gaseous analytes can be collected, and sufficient analytical sensitivity can be obtained.
The diameter of the filter paper is desirably 10 mm to 47 mm.

The absorbent-impregnated filter paper used as the collector can be appropriately selected according to the target gaseous test substance. For example, to collect nitrogen dioxide (NO ₂ ), sulfur dioxide (SO ₂ ), and hydrogen chloride (HCl), to collect triethanolamine-impregnated filter paper, hydrogen sulfide (H ₂ S), and carbonyl sulfide (COS). Is a silver nitrate impregnated filter paper, potassium hydroxide impregnated filter paper for collecting organic acids such as formic acid / acetic acid, boric acid impregnated filter paper for collecting ammonia (NH ₃ ), and iodine for collecting ozone. For collecting potassium impregnated filter paper, aldehydes and ketones, 2,4-dinitrophenylhydrazine impregnated filter paper, and collecting nitric oxide (NO), 2-phenyl-4,4,5,5-tetramethyl An imidazoline-3-oxide-1-oxyl (PTIO) -triethanolamine-impregnated filter paper can be used.

As the diffusing body 3, a planar porous body having continuous pores obtained by sintering or welding resin particles and molding them is used. In the planar porous body, the gap between the sintered or welded resin particles is connected as a continuous hole in the thickness direction of the planar porous body. When the passive collector is used, the gaseous test substance passes through the continuous hole according to the principle of molecular diffusion and reaches the collector.
As the resin particles, those having little interaction with the gaseous test substance are preferable, and the resin particles are preferably made of at least one resin selected from the group consisting of polyethylene, polypropylene, fluororesin and polyester.

  For example, the planar porous body is uniformly filled with resin particles in a mold, the mold is heated to 100 to 250 ° C., kept warm for about 5 to 20 minutes, and the resin particles are sintered or welded and cooled. Can be manufactured. The preferred heating temperature varies depending on the material of the resin particles. When polystyrene is used for the resin particles, about 80 to 120 ° C., when polyethylene is used for the resin particles, about 140 to 180 ° C., and polypropylene is used for the resin particles. When using it, it is preferable that it is about 170-210 degreeC, and when using a fluororesin for a resin particle, it is preferable about 180-250 degreeC. Examples of the cooling method include natural cooling and cooling with a cooling fan.

The thickness of the planar porous body is preferably 0.5 to 2.0 mm. When the thickness of the planar porous body is within the above range, the gaseous test substance can be sufficiently collected without being affected by the wind speed, and the gaseous test substance is not diffused by molecules. Since the resistance when passing in principle is small, a sufficient amount of a gaseous test substance can be collected in a short time, for example, in units of several hours, and sufficient analytical sensitivity can be obtained.
The thickness of the planar porous body is desirably 0.75 to 1.5 mm.

Moreover, in a planar porous body, it is preferable that the average hole diameter of a continuous hole is 10-100 micrometers. When the average pore diameter of the continuous holes is within the above range, the gaseous test substance can be sufficiently collected without being affected by the wind speed, and the gaseous test substance passes on the principle of molecular diffusion. Therefore, a sufficient amount of a gaseous test substance can be collected in a short time, for example, in units of several hours, and sufficient analysis sensitivity can be obtained.
The average pore diameter of the continuous pores is desirably 20 to 80 μm.

Moreover, it is preferable that the porosity of a planar porous body is 20 to 75%. When the porosity of the planar porous material is within the above range, the gaseous test substance can be sufficiently collected without being affected by the wind speed, and the gaseous test substance can be molecularly diffused. Therefore, a sufficient amount of gaseous test substance can be collected in a short time, for example, in units of several hours, and sufficient analysis sensitivity can be obtained.
The porosity of the planar porous body is desirably 50 to 70%.

  In the passive collector, it is necessary to set the dimensions of the collector and the diffuser so that the gaseous test substance does not pass through the diffuser and does not reach the collector directly. For this reason, in FIGS. 1A and 1B, the diameter of the disc-shaped diffuser 3 needs to be equal to or larger than the diameter of the collector 2.

The material of the stopper 4 is not particularly limited as long as it has no significant adsorptivity or reactivity with respect to the gaseous test substance and the absorbent used in the collector 2, but polyethylene, polypropylene, fluororesin, polyester ABS resin, glass, quartz or stainless steel is preferable.
In the case of the stopper 4 shown in FIGS. 1 (a) and 1 (b), the inner diameter and the diameter of the opening at the left end of the drawing are the diameter of the absorbent-impregnated filter paper used as the collector 2 and the diffuser 3. It is necessary to make it equal to or larger than the diameter of the disk-like planar porous body. On the other hand, the diameter of the opening at the right end of the drawing needs to be smaller than these diameters.
The stop may have a lid to keep the opening of the stop closed when no passive collector is used.
In the passive collector of the present invention, the stopper is not an essential component. If the collector and the diffuser can be laminated and fixed in this order to the support by another means or method, the stopper is attached. It is not necessary to use it.
In addition, when using a stopper, the structure for locking and fixing the collector and the diffuser is not limited to a small-diameter part such as the stopper 4 shown in FIGS. 1 (a) and 1 (b). For example, a claw-like structure for locking and fixing the collector and the diffuser may be provided in the opening at the right end of the drawing.

  In the passive body collector of the present invention, since the collector and the diffuser are laminated and fixed in this order with respect to the support body, like the passive sampling adsorption device described in Patent Documents 3 to 6, In this case, the moving amount of the absorber causes variations in the collected amount, and there is no possibility that the measurement accuracy is lowered. In addition, in the adsorption apparatus for passive sampling described in Patent Documents 3 to 6, when absorbent-impregnated filter paper is used instead of particulate adsorbent, the absorbent-impregnated filter paper is fixed to a container made of a porous material. For this reason, there is a gap between the container and the absorbent-impregnated filter paper due to the movement of the absorbent-impregnated filter paper in the container, and the shape inside the container and the shape of the absorbent-impregnated filter paper do not match. There is a possibility that the collection amount varies and the measurement accuracy decreases.

The procedure for using the passive collector of the present invention is as follows.
A passive collector is installed in an environment in which a gaseous test substance is measured, and the passive collector is exposed to air in the environment for a certain period of time. Thereafter, the absorbent-impregnated filter paper as a collector is taken out from the passive collector and the gaseous test substance is desorbed and eluted, followed by liquid chromatography, gas chromatography, gas chromatography-mass spectrometer, ion chromatography, Identification and quantification of a gaseous test substance is performed by spectrophotometric analysis, fluorescent photometric analysis, or the like.

The passive collector of the present invention can collect various gaseous test substances by appropriately selecting an absorbent-impregnated filter paper to be used as a collector according to the gaseous test substance. Examples of gaseous test substances include acidic substances or basic substances known as gaseous harmful pollutants in the atmosphere. Specifically, nitric oxide (NO), nitrogen dioxide (NO ₂ ), Organic acids such as sulfur dioxide (SO ₂ ), hydrogen sulfide (H ₂ S), carbonyl sulfide (COS), hydrogen chloride (HCl), ammonia (NH ₃ ), formic acid and acetic acid can be mentioned. Further, ozone and aldehydes / ketones are also included as gaseous test substances other than those described above.
In the passive collector of the present invention, after collecting the target gaseous test substance in the above procedure, the absorbent-impregnated filter paper used as the collector is taken out and replaced with another absorbent-impregnated filter paper. It is possible to quickly collect another gaseous test substance.
In FIGS. 1 (a) and 1 (b), the collector 2 and the diffuser 3 are laminated and fixed on one end surface of the columnar support 1, and are captured on both end surfaces of the columnar support. The collector and the diffuser may be laminated and fixed. At this time, if different absorbent-impregnated filter papers are used as collectors fixed to both end faces, different gaseous test substances can be collected simultaneously.

これらの平面状多孔質体を、それぞれ、ジエチルエーテルを満たしたガラス管（外径１３ｍｍ内径１２ｍｍ）の開口端に取り付け、風洞の風下に設置した。風洞内では乱流が発生しており、撹拌ファンの回転数を変化させてガラス管近傍の風速を変化させた。一定時間ごとにガラス管の全重量を測定し、ジエチルエーテルの蒸発に伴う重量変化に及ぼす風速の影響を調べた。同様にＰａｌｍｅｓ ｔｕｂｅ（Ｇｒａｄｋｏ社製）の拡散部、オガワ・サンプラー（小川商会製）の多孔栓についても同様の測定を行った。図２に結果を示す。
図２の横軸はガラス管近傍での風速を示しており、縦軸は各風速における重量変化Ｍ（ｇ／ｈ）を無風時の重量変化Ｍｏ（ｇ／ｈ）で除した値を示している。図２から明らかなように、Ｐａｌｍｅｓ ｔｕｂｅの拡散部、オガワ・サンプラーの多孔栓を用いた場合、重量変化が風速によって著しく変化した。これらを拡散体として使用した場合、ガス状被検物質の捕集量が風速による影響を受けやすいことを示している。一方、本発明の受動的捕集器で拡散体として使用する平面状多孔質体では風速２ｍ／ｓ付近でも有意な風速の影響は見られなかった。ここから、本発明の受動的捕集器の場合、ガス状被検物質の捕集量が風速による影響を受けにくいことがわかった。 Hereinafter, reference examples and examples will be described.
[Reference example]
A planar porous body used as a diffuser in the passive collector of the present invention was prepared by the following procedure. Two types of planar porous bodies (thickness 0.75 mm, 1 mm) having different thicknesses were prepared by welding and molding polyethylene resin particles (particle diameter 25 μm). The planar porous body has a disk shape with a diameter of 13 mm, and the gap between the welded polyethylene resin particles is connected as a continuous hole in the thickness direction of the planar porous body. The planar porous body has the following average pore diameter and porosity of the continuous pores.

Each of these planar porous bodies was attached to the open end of a glass tube (outer diameter 13 mm, inner diameter 12 mm) filled with diethyl ether, and installed in the lee of the wind tunnel. Turbulence was generated in the wind tunnel, and the wind speed near the glass tube was changed by changing the rotation speed of the stirring fan. The total weight of the glass tube was measured at regular intervals, and the influence of the wind speed on the weight change accompanying the evaporation of diethyl ether was investigated. Similarly, the same measurement was performed on the diffusion part of Palmes tube (manufactured by Gradko) and the porous plug of Ogawa Sampler (manufactured by Ogawa Shokai). The results are shown in FIG.
The horizontal axis of FIG. 2 shows the wind speed in the vicinity of the glass tube, and the vertical axis shows the value obtained by dividing the weight change M (g / h) at each wind speed by the weight change Mo (g / h) when there is no wind. Yes. As is clear from FIG. 2, when the Palmes tube diffusion part and the Ogawa sampler perforated plug were used, the weight change significantly changed depending on the wind speed. When these are used as a diffuser, the trapped amount of the gaseous test substance is easily affected by the wind speed. On the other hand, in the porous porous body used as a diffuser in the passive collector of the present invention, no significant influence of the wind speed was observed even in the vicinity of the wind speed of 2 m / s. From this, it was found that in the case of the passive collector of the present invention, the trapped amount of the gaseous test substance is hardly affected by the wind speed.

…(2)
ここでＭＷはＮＯ₂の分子量、Ｔは温度（℃）である。
（２）式によれば、２５℃における捕集速度は１２（ｍｌ／ｍｉｎ）である。 [Example 1]
Nitrocellulose filter paper (Whatman # 1, 13 mmφ) was dipped in a 10% triethanolamine / acetone solution and pulled up, and dried on a fluororesin mesh for 30 minutes to prepare a collector. On one end face of a columnar support (made of glass) having a diameter of 13 mm and a length of 40 mm, this collector and a planar porous body (thickness of 0.75 mm) created in the above procedure are laminated in this order. The passive collector shown in FIGS. 1A and 1B was created (hereinafter referred to as “# 0.75 sampler”). Call). This passive collector was installed near the sampling port of the NO ₂ concentration automatic measuring machine in two locations in Oxford, England (High Street, Carfax) and in two locations in Kanagawa, Japan (Ogino, Isehara). And exposed to the air for 24 hours (measurement period: City of Oxford: September 11-19, 2004, Kanagawa: November 10-18, 2004). After exposure, the collector was removed from the passive collector and the collected NO ₂ was analyzed by the sulfanilamide / NEDA method. The results are shown in FIG. The horizontal axis of FIG. 3 shows the 24-hour average value of the atmospheric NO ₂ concentration measured by the automatic measuring machine, and the vertical axis shows the amount of NO ₂ collected by the passive collector. A good linear relationship is observed between the _two , and when the collection time is t (h) between the NO ₂ concentration C (ppm) and the NO ₂ collection amount W (μg), the equation (1) The relationship was led.
C = W / (1.3 × t) (1)
Further, from this coefficient α = 1.3 (μg / ppm / h), the NO ₂ collection speed S in the # 0.75 sampler can be obtained from the equation (2).

… (2)
Here, MW is the molecular weight of NO ₂ , and T is the temperature (° C.).
According to equation (2), the collection rate at 25 ° C. is 12 (ml / min).

[Example 2]
Nitrocellulose filter paper (Whatman # 1, 13 mmφ) was dipped in a 10% triethanolamine / acetone solution and pulled up, and dried on a fluororesin mesh for 30 minutes to prepare a collector. A state in which this collector and a planar porous body (thickness: 1.0 mm) prepared in the above procedure are laminated on one end face of a cylindrical support (made of glass) having a diameter of 13 mm and a length of 40 mm. And fixed by using a substantially cylindrical stopper, and the passive collector shown in FIGS. 1A and 1B was created (hereinafter referred to as “# 1.0 sampler”). . This passive collector was installed in the vicinity of the sampling port of the NO ₂ concentration automatic measuring machine in two locations in Oxford City, England (High Street, Carfax) and in two locations in Kanagawa Prefecture, Japan (Ogino, Isehara) It was exposed to the air for 24 hours (measurement period: City of Oxford: September 11-19, 2004, Kanagawa Prefecture: November 10-18, 2004). After exposure, the collector was removed from the passive collector and the collected NO ₂ was analyzed by the sulfanilamide / NEDA method. The results are shown in FIG. The horizontal axis represents the 24-hour average value of the atmospheric NO ₂ concentration measured by an automatic measuring machine, and the vertical axis represents the NO ₂ trapped amount collected by the passive collector. A good linear relationship is recognized between the _two , and when the collection time is t (h) between the NO ₂ concentration C (ppm) and the NO ₂ collection amount W (μg), the equation (3) The relationship was led.
C = W / (1.2 × t) (3)
Further, from this coefficient α = 1.2 (μg / ppm / h), the collection speed S for NO ₂ of the # 1.0 sampler can be obtained from the equation (2). The collection rate at 25 ° C. was 11 (ml / min).

[Example 3]
A # 0.75 sampler and a # 1.0 sampler were prepared in the same procedure as in Examples 1 and 2. These passive collectors were installed near the sampling port of the NO ₂ concentration automatic measuring machine in Sagano, Kanagawa, Japan and exposed to air for 3, 6, 12 and 30 hours (measurement period: Sagano, Kanagawa) November 29-30, 2004). After exposure, the collector was removed from the passive collector and the collected NO ₂ was analyzed by the sulfanilamide / NEDA method. FIG. 5 shows a comparison between NO ₂ concentration measurement values obtained by the # 0.75 and # 1.0 samplers at each measurement time and NO ₂ concentration measurement values obtained by the automatic measuring machine. The NO ₂ concentration measured values by the # 0.75 and # 1.0 samplers are obtained by converting the respective NO ₂ collection amounts into the concentrations by the equations (1) and (2). As is clear from the figure, the values measured by these passive collectors and the values obtained by the automatic measuring machine were in good agreement, and the NO ₂ concentration could be measured with high accuracy even in a short collection time (3 hours). .

1 (a) and 1 (b) show an example of an embodiment of the passive collector of the present invention. Fig.1 (a) is a side view of the passive collector of this invention, FIG.1 (b) is a perspective view of a passive collector. FIG. 2 is a graph showing the results of the reference example. FIG. 3 is a graph showing the results of Example 1. FIG. 4 is a graph showing the results of Example 2. FIG. 5 is a graph showing the results of Example 3.

Explanation of symbols

1 Support body 2 Collection body (absorbent impregnated filter paper)
3 diffuser (planar porous body)
4 Stopper

Claims (4)

A collector of a gaseous test substance and a diffuser through which gas molecules pass on the principle of molecular diffusion are laminated and fixed in this order on the support,
The collector is a filter paper impregnated with an absorbent of the gaseous test substance;
The diffuser is a planar porous body obtained by sintering or welding resin particles and molding,
In the diffuser, a passive collector for a gaseous test substance, wherein a gap between the sintered or welded resin particles is connected as a continuous hole in the thickness direction of the diffuser.   2. The passive collector for a gaseous test substance according to claim 1, wherein the resin particles are made of at least one resin selected from the group consisting of polyethylene, polypropylene, fluororesin, and polyester.   The diffuser has a thickness of 0.5 to 2.0 mm, a pore diameter of the continuous hole of 10 to 100 µm, and a porosity of 20 to 75%. 2. A passive collector of the gaseous test substance according to 2.   The passive capture of a gaseous test substance according to any one of claims 1 to 3, wherein the support has a circular planar shape at a portion where the collector and the diffuser are stacked and fixed. Collector.

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