JP2002328077A - Method and apparatus for simply collecting material in the air - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ideal method and an ideal apparatus for adsorbing a sample which do not use motive energy of a motor, etc., have a very simple structure as a passive sampler, can be inexpensively manufactured, increase the number of measurement by using a plurality of the apparatuses at the same time, can collect the samples without variations, have low resistance in an adsorbing agent since a loss of ventilating pressure is small and a surface area is large as a collecting agent. SOLUTION: The method for collecting the material in the air such as a gas material in the air, etc., in a pipe uses a collecting pipe that an unbound structured porous element comprising an inorganic, organic or hybrid polymer is formed in a part or whole part of a prime pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple method and apparatus for trapping atmospheric substances, and more particularly, to gaseous organic substances such as aldehydes and benzene, and gases such as nitrogen oxides and sulfur oxides in the atmosphere. The present invention relates to a simple method and apparatus for trapping air pollutants such as inorganic substances.

[0002]

2. Description of the Related Art An active sampling method is generally used for collecting gaseous components in the atmosphere, in which the atmosphere is suctioned at a constant flow rate using a pump or the like and the components to be measured are collected on activated carbon or the like. Alternatively, there is a method in which an air sample is guided to a reagent by an impinger and the sample is absorbed by a chemical reaction. The target component is collected and desorbed by heating or extracted with an organic solvent and analyzed and quantified. In this case, the sampling amount of the sample is obtained from the suction flow rate of the pump.

On the other hand, in recent years, a passive sampler which is a simple measuring instrument which is small and requires no power has been proposed. Passive samplers do not have a mechanism to control the flow of gas on the measuring instrument side, but allow the target component and the adsorbent to come into contact only by the flow due to the molecular diffusion of the gas and passively adsorb the substance to be adsorbed to the adsorbent. It is.

[0004]

In the so-called active sampling method, since the atmosphere is sucked by the power of a pump or the like, the number of sampling points most important for the measurement of atmospheric substances is large. Therefore, it is difficult to suppress the variation due to the limitation of the number of measurements. In addition, by using a filler such as an activator as a trapping agent, the air pressure loss is large, and the resistance of the adsorbent becomes large. In addition, when the solvent is desorbed after collection, a large amount of the solvent is required, that is, 2 to 20 mL. When actually performing the quantitative analysis, for example, a part of the solvent introduced into the chromatograph is 1 to 20 μL. And wasteful.
Therefore, it becomes impossible to measure components having low sensitivity.

On the other hand, collection in passive sampling
The relationship between time and the amount collected can be expressed as follows. H = D × (A / L) × (Ca−Cs) = K_OG× A ×
(Ca-Cs) H: target flux (G), M: target substance collection amount (G) A: diffusion cross section (cm)²), L; diffusion distance (cm) D; diffusion coefficient (cm)²/ S), K_OG; General Mass Transfer Section
Number (cm / s) Ca; Outer tube boundary concentration (g / cm²), Cs; adsorption phase side
Boundary concentration (g / cm ²Analyte that has reached the adsorption phase is completely collected by the adsorbent
Assuming (Cs = 0), sampling was performed for t seconds.
The collected amount (g) in the case is as follows. M = D × (A / L) × Ca × t = K_OG× A × Ca × t K in the above formula_OG× A dimension is cm³/ S, acty
This corresponds to the pump flow rate of bus sampling. In other words, passive
KoG is constant during sampling in the bus sampler
Is indispensable for accurate measurement.
You.

[0006] In a static environment where the outside air is stable, _KOG is a constant value because it is determined by the atmospheric components and the collection tube. However, in an actual measurement environment where the air flow is constantly changing, the KoG fluctuates during the measurement because the change in the air flow causes a change in the boundary layer resistance. K during this measurement
Variations in _OG contribute to variations in measured values.

In recent years, SPME (Solid Phase Micro Extr)
action) A passive sampler using fiber as adsorbent was devised. (Eg PAMartos, J. Pawliszy
n; Analytical Chemistry 71, 1513, 1999) This method does not use plastic materials often used in conventional passive samplers, so there is no concern that interfering components elute during extraction. Also, the diffusion length can be changed more freely than in a conventional badge type sampler. However, if the adsorbent film pressure is increased to increase the sample load, it takes time for the target substance to diffuse and penetrate from the surface of the adsorbent to the inside, resulting in poor contact efficiency. Further, when the target substance is separated, the efficiency is extremely poor for the same reason.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a so-called passive sampler that does not use the power of a motor or the like, can be manufactured at a low cost with a very simple structure, and can be used in large numbers in the same manner. It provides an ideal sample adsorption method and apparatus that can increase the number of measurements, collect samples without variation, and have a low surface pressure and a large surface area as a collecting agent, so that the resistance of the adsorbent is low and the sample is adsorbed. First, a method for trapping atmospheric substances such as gaseous substances in the atmosphere in a pipe, using a trapping pipe in which a porous body having an open structure made of an inorganic, organic or hybrid polymer is formed in a base pipe. And secondly, as a collection tube,
It is characterized by forming an open structure porous body made of inorganic, organic or hybrid polymer by placing an appropriate cavity from the end of the tube at a part of the tube. Fourth, a porous material having an open structure made of a substance that does not adsorb components is used. After the gas components are collected using the simple method for collecting atmospheric substances according to claim 1, solvent extraction, It is characterized in that the trapping component is introduced into an analyzer such as a chromatograph through an appropriate extraction means such as heat extraction.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a tube made of metal, fused silica, etc.
The inside thereof is filled with a porous body 2 having a release structure having an appropriate length over the entire shape. It is recommended that the cavity 3 be formed between the one end 11 of the raw tube 1 and the upper end 21 of the porous body 2. The tube 1 is similar to an analytical column such as a capillary column for convenience, and its inner diameter is 0.1 mm to 1.5 m.
m and a length of 1 mm to 300 mm are used. As a specific example, the raw tube 1 is made of fused silica and has an inner diameter of 0.25 mm,
0.32mm and 0.53mm
10 to 10 mm, that is, the cavity 3 and the porous body 2
Fill and form to a length of 15 mm. The rear portion of the porous body 2 may be a cavity 4 having an appropriate length, for example, 10 mm.

As a result, the diffusion control portions of the cavities 3 and 4 are formed in the tubes at both ends of the porous body 2, and sampling can be performed from both ends at once. According to this method, the amount sampled in a certain time can be easily increased, and a trace component can be analyzed. The porous body 2 is preferably filled and formed in the tube by an integral structure. However, an appropriate number of the integrally formed porous bodies 2 may be inserted and filled in the raw tube 1. Further, it is also recommended that the appropriate number of porous bodies of thin tubes be bundled together and sampled. By doing so, a plurality of points can be sampled by one sampling, and the handling operation and movement become very simple.

The details of the porous body will be described below.
You. The porous body used in the present invention is described below.
With pores that communicate from the top to the bottom
It has a release structure. Of course, the pores are axially sectioned
Is preferably circular or close to it, and the material of the porous body
Is a material that can control the macropore diameter to the following size
If there is, it is not particularly limited, but porous ceramic, porous
Inorganic porous material such as porous glass, for example, porous glass
Is desirable. As an example of the porous glass, the composition is NaO
―B₂O₃―SiO₂—CaO-based ones;
l₂O₃, ZrO₂, ZnO₂, TiO₂, SnO₂,
MgO ₂Manufactured using glass to which various oxides are added.
It may be made. (This point is disclosed in JP-A-7-120350.
There is a description. )

The porous glass is, for example, silica sand, boric acid,
Mix soda ash and alumina, 1200-1400 ° C
Melts. After forming this at 800 to 1100 ° C., an unseparated borosilicate glass is obtained, and the SiO ₂ phase and B ₂
A phase is separated into an O ₃ —Na ₂ O—CaO phase, and an acid treatment is performed to produce a porous body having a SiO ₂ skeleton. By changing the conditions of the heat treatment depending on the application, the pore size can be uniform with a pore distribution of 0.1 to 10 μm depending on the application.

Examples of porous ceramics include silica,
Examples include alumina silicate A (sintered hard magnetic particles), silica sand, alumina, alumina silicate B (sintered chamotte particles), porous mullite, and diatomaceous earth. Porous ceramics include, for example, ceramic particles (hard magnetic pulverized material,
(Silica, alumina, chamotte, etc.) and a pore-forming material, for example, crystalline cellulose (Asahi Kasei: Avicel), and a suitable dispersing solvent, and are mixed, molded, and sintered. Pore diameter 500μ
Those having a range of about m to about 0.1 μm or more and having a uniform pore distribution can be manufactured according to the application.

The above-mentioned pores can be modified / modified on the surface of the pores by applying a coating agent and / or a chemical modifier suitable for a separation sample used in a conventional packing material. Examples of the coating agent include polyethylene glycol and silicone oil. As chemical modifiers, trimethylchlorosilane (TMS), dimethyl-
Examples include alkylsilanes such as n-octylchlorosilane and dimethyl-n-octadecylchlorosilane (ODS), aminoalkoxysilanes such as r-aminopropyltriethoxysilane, and various silane treatment agents such as epoxysilane. Furthermore, a high molecular compound such as a protein or a low molecular compound may be bonded to the modifying group of the surface modifying agent.

When a non-porous filler is packed in a column, pores are formed only between particles, and this is called a single pore. When silica gel particles having pores are packed in a column, the column has a double structure of pores in the particles and pores between the particles. This is called a double pore. When a non-porous filler is filled, it is a single pore, but the shape of the space changes depending on the state of the particles, and the separation mode becomes complicated. Further, separation by double pores does not result in simple adsorption distribution, and the separation mode is not simple. Therefore, a single pore in a state where the shape of the space does not change is recommended. This is the same for the porous body.

By filling part or all of the cavity 3 of the raw tube 1 with the above-mentioned porous body and other porous bodies, the flow of the atmosphere to the raw tube 1 can be made closer to laminar flow. Become. Examples of the porous body 5 include polyethylene, polypropylene, polyethylene terephthalate, urethane foam, silica, titania, zirconia, alumina, and hydroxyapatite in addition to the above.

A description will be given of a collecting process in the case where the gaseous component in the atmosphere is passively sampled by using the tubular collecting tube A having the above-described configuration. Outside the tube 1, there is no concentration gradient due to turbulence in the flow. However, the one end 11 of the tube 1 and the boundary layer outside the tube 1 have a resistance R against the flow of the measurement component into the tube 1.
_{There is one} . Next, in the cavity 3 serving as the diffusion controller, ideally, there is no turbulence and the flow is laminar, so that a concentration gradient exists. Flow by molecular diffusion to a resistance received when passing through this portion and R _2. Furthermore, the resistance R ₃ with the physical and chemical adsorption is present at the boundary between the porous body 2 and the cavity 3 as an adsorbent.

When the resistance value is defined as described above, the total
The mass transfer coefficient is KoG = 1 / (R ₁+ R₂+ R₃)so
expressed. All measured components that have reached near the adsorbent are absorbed.
Assuming that₃= 0. Therefore depending on wind speed
To minimize the change in KoG, R₂Is R₁Strange
Design the collection tube to obtain a sufficiently large value for the movement
do it.

[0019]

[Example 1] 10 ppm of benzene in the atmosphere was collected by a collection tube having a pipe diameter of 0.032 cm and a diffusion length of 1 cm.
Time sampling. Eight hours, 10 ppm is based on the indoor environmental guideline benzene value set by the US Occupational Safety and Health Administration. Since the diffusion coefficient at 1 atm, 25 ° C. of benzene is 0.09cm2 / S, M = D × (A / L) × (Ca-Cs) × t = 0.09 × (π × 0.016 2/1) × ( 10 × 10 ⁻⁶ × 10 ⁻³ × 3.49) × (8 × 3600) = 0.29 μg The amount of benzene trapped using the present collection method and apparatus is 0.29 μg. This amount falls within the range of sensitivity of a flame ionization detector (FID), which is a general detection amount of a gas chromatograph, so that quantitative analysis is sufficiently possible. The relationship between the benzene concentration and the amount collected is shown in FIG.

[Table 1]

Example 2 Sample: 0.07 ppm of toluene (indicator of indoor concentration) in the atmosphere was sampled using the following collecting tube. Collection tube: Diffusion phase: Porous silica having a monolith structure of 50 μm through-pore Collector: ODS treatment of 50 μm through-pore, silica monolith having a monolith structure of 100 nm mesopore Overall mass transfer coefficient: KOG = 0. 0308 (cm / s) Collection time: 24 hours Since the overall mass transfer coefficient of the collection tube is KOG = 0.0308 (cm / s), M = D × (A / L) × (Ca−Cs) × t ^{= 0.0308 × (π × 0.016 2} /1)×(0.07×10 -6 × 10 -3 × 3.49) × (24 × 3 600) = 0.53μg present collection method and benzene are trapped using the apparatus The amount is 0.53 μg. This amount falls within the range of sensitivity of a flame ionization detector (FID), which is a general detection amount of a gas chromatograph, so that quantitative analysis is sufficiently possible. The relationship between the toluene outside air concentration and the trapped amount is shown in FIG.

[Table 2]

Example 3 Benzene was measured in a working environment in an organic synthesis building in a factory. Collection tube: As a diffusion control unit of 0.032 cm, a cavity 1 cm from the end of the tube is provided on the entrance side, and a through-pore 50
A porous silica having a monolithic structure of 100 μm and a mesopore of 100 μm was formed by forming 2 cm of a collecting agent subjected to an ODS treatment and bundling seven tubes sealed at both ends. a. Open the sampling tube at the measurement point and start sampling. b. After 8 hours, the collection tube is sealed. c. The collection tube is attached to a heat desorption section connected to a gas chromatograph. d. Perform quantitative analysis under the following conditions. Device configuration: Injection port-(rapid heating unit + collection element tube)-GC
(FID) Separation column: TC. 1. Inner diameter 0.25mm, membrane pressure 0.1
μm, 15 m Inlet temperature: 120 ° C. Column temperature: 120 ° C., detector temperature: 120 ° C. Carrier gas: He, carrier pressure 150 kPa Rapid heating unit temperature program: 20 ° C. (3 minutes) -100 ° C.
/ S-120 ° C (10 minutes) e. Table 3 shows the results of analysis by GC-FID.

[Table 3] From this, the measured value was 60.1 (ppb / 8 hour average: N
= 7), and the CV value was 5.6%.

As described above, in the case where the intended control component is released by a solvent, the use of a solvent reduces the amount of the solvent and reduces the possibility of contaminating the environment, as compared to a conventional passive sampler, which is a thin tube. The detachment by heating can be performed in a very easy and short operation time.

[0023]

According to the first aspect of the present invention, a so-called passive sampler that does not use the power of a motor or the like can be manufactured at a low cost with an extremely simple structure, and the number of measurements can be increased by using a large number of samples in the same manner. It is possible to provide an ideal sample adsorbing method and apparatus with low resistance to the adsorbent because of low sample pressure and low surface pressure as a trapping agent.

According to the second aspect of the present invention, in addition to the above effects, when the sample reaches the adsorbent through the cavity in the tube, a diffusion control effect based on molecular diffusion of the substance to be measured is obtained. Overall mass transfer coefficient K _OG during the process of trapping the substance to be measured through the hollow part of the tube into the porous material (from the time the target substance moves from the atmosphere outside the column to the surface of the adsorbent inside the column and is collected) Has an effect of suppressing a change in the measurement environment (such as a temporal change in wind speed), and an error caused by measurement environment factors such as a change in wind speed during measurement can be suppressed.

According to the third aspect of the present invention, there is an effect that the overall mass transfer coefficient, which is the effect of the second aspect, is further stabilized, and the measured value is further stabilized. Furthermore, according to the fourth aspect, the extremely inexpensive and efficiently collected sample can be efficiently introduced into the analyzer as described above, and extremely efficient analysis of atmospheric substances has become possible.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a slope according to an embodiment of the present invention.

FIG. 2 is a schematic explanatory top view of another embodiment of the present invention.

FIG. 3 is a diagram illustrating the operation of the present invention.

FIG. 4 is a schematic perspective view illustrating another embodiment of the present invention.

FIG. 5 is a measurement diagram of one embodiment of the present invention.

FIG. 6 is a measurement diagram of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base tube 2 Porous body 3 cavity 4 cavity

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] May 8, 2001 (2001.5.8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

Patent application title: Simple method and apparatus for trapping atmospheric substances

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple method and apparatus for trapping atmospheric substances, and more particularly, to gaseous organic substances such as aldehydes and benzene, and gases such as nitrogen oxides and sulfur oxides in the atmosphere. The present invention relates to a simple method and apparatus for trapping atmospheric substances such as inorganic substances.

[0002]

2. Description of the Related Art An active sampling method is generally used for collecting gaseous components in the atmosphere, in which the atmosphere is suctioned at a constant flow rate using a pump or the like and the components to be measured are collected on activated carbon or the like. Alternatively, there is a method in which an air sample is guided to a reagent by an impinger and the sample is absorbed by a chemical reaction. The target component is collected and desorbed by heating or extracted with an organic solvent and analyzed and quantified. In this case, the sampling amount of the sample is obtained from the suction flow rate of the pump.

On the other hand, in recent years, a passive sampler which is a simple measuring instrument which is small and requires no power has been proposed. Passive samplers do not have a mechanism to control the flow of gas on the measuring instrument side, but allow the target component and the adsorbent to come into contact only by the flow due to molecular diffusion of the gas and passively adsorb the substance to be adsorbed to the adsorbent. It is.

[0004]

In the so-called active sampling method, since the atmosphere is sucked by the power of a pump or the like, most of the so-called active sampling methods measure many sampling points which are most important for measurement of atmospheric substances. Therefore, it is difficult to suppress the variation due to the limitation of the number of measurements. Also active as a collector
By using a filler such as charcoal , the air pressure loss is large, and the resistance of the adsorbent becomes large. In addition, when the solvent is desorbed after collection, a large amount of the solvent is required, that is, 2 to 20 mL. And wasteful.
Therefore, it becomes impossible to measure components having low sensitivity.

On the other hand, collection in passive sampling
The relationship between time and the amount collected can be expressed as follows. H = D × (A / L) × (Ca−Cs) = K_OG× A ×
(Ca-Cs) H: target flux (G), M: target substance collection amount (G) A: diffusion cross section (cm)²), L; diffusion distance (cm) D; diffusion coefficient (cm)²/ S), K_OG; General Mass Transfer Section
Number (cm / s) Ca; Outer tube boundary concentration (g / cm²), Cs; adsorption phase side
Boundary concentration (g / cm ²Analyte that has reached the adsorption phase is completely collected by the adsorbent
Assuming (Cs = 0), sampling was performed for t seconds.
The collected amount (g) in the case is as follows. M = D × (A / L) × Ca × t = K_OG× A × Ca × t K in the above formula_OG× A dimension is cm³/ S, acty
This corresponds to the pump flow rate of bus sampling. In other words, passive
During sampling in the bus samplerK _{O G} The constant
Is indispensable for accurate measurement.
You.

[0006] In a static environment where the outside air is stable, _KOG is a constant value because it is determined by the atmospheric components and the collection tube. However, in the actual measurement environment that atmospheric air is constantly changing, the change in airflow to cause a change in the boundary layer resistance, K _OG varies during the measurement. K during this measurement
Variations in _OG contribute to variations in measured values.

In recent years, SPME (Solid Phase Micro Extr)
action) A passive sampler using fiber as adsorbent was devised. (Eg PAMartos, J. Pawliszy
n; Analytical Chemistry 71, 1513, 1999) This method does not use plastic materials often used in conventional passive samplers, so there is no concern that interfering components elute during extraction. Also, the diffusion length can be changed more freely than in a conventional badge type sampler. However, if the thickness of the adsorbent is increased in order to increase the sample load, it takes time for the target substance to diffuse and permeate from the surface of the adsorbent, resulting in poor contact efficiency. Further, when the target substance is separated, the efficiency is extremely poor for the same reason.

[0008]

Means for Solving the Problems] The present invention, in order to solve the above problems, without using the power of a motor or the like, can be inexpensively manufactured in a very simple structure as a so-called passive sampler, using a number simultaneously Increases the number of measurements, allows for sample collection without variation, and as a collecting agent
Since the air pressure loss is low and the surface area is large, the resistance to the adsorbent is small and an ideal sample adsorption method and apparatus are provided. The first method is to collect atmospheric substances such as gaseous substances in the atmosphere into a pipe. The use of a collection tube in which a porous body having an open structure made of an inorganic, organic, or hybrid polymer is formed in a base tube, and secondly, as a collection tube,
It is characterized by forming a porous body of an open structure made of inorganic, organic or hybrid polymer by placing an appropriate cavity from the end of the tube at a part in the tube. Fourth, a porous material having an open structure made of a substance that does not adsorb components is used. After the gas components are collected using the simple method for collecting atmospheric substances according to claim 1, solvent extraction, It is characterized in that the trapping component is introduced into an analyzer such as a chromatograph through an appropriate extraction means such as heat extraction.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a tube made of metal, fused silica, etc.
The inside thereof is filled with a porous body 2 having a release structure having an appropriate length over the entire diameter . It is recommended that the cavity 3 be formed between the one end 11 of the raw tube 1 and the upper end 21 of the porous body 2. The tube 1 is similar to an analytical column such as a capillary column for convenience, and its inner diameter is 0.1 mm to 1.5 m.
m and a length of 1 mm to 300 mm are used. As a specific example, the raw tube 1 is made of fused silica and has an inner diameter of 0.25 mm,
0.32mm and 0.53mm
10 to 10 mm, that is, the cavity 3 and the porous body 2
Fill and form to a length of 15 mm. The rear portion of the porous body 2 may be a cavity 4 having an appropriate length, for example, 10 mm.

As a result, the diffusion control portions of the cavities 3 and 4 are formed in the tubes at both ends of the porous body 2, and sampling can be performed at once from both ends. According to this method, the amount sampled in a certain time can be easily increased, and a trace component can be analyzed. The porous body 2 is preferably filled and formed in the tube by an integral structure. However, an appropriate number of the integrally formed porous bodies 2 may be inserted and filled in the raw tube 1. Further, it is also recommended that the appropriate number of porous bodies of thin tubes be bundled together and sampled. By doing so, a plurality of points can be sampled by one sampling, and the handling operation and movement become very simple.

The details of the porous body will be described below.
You. The porous body used in the present invention is described below.
With pores that communicate from the top to the bottom
It has a release structure. Of course, the pores are axially sectioned
Is preferably circular or close to it, and the material of the porous body
Is a material that can control the macropore diameter to the following size
If there is, it is not particularly limited, but porous ceramic, porous
Inorganic porous material such as porous glass, for example, porous glass
Is desirable. As an example of the porous glass, the composition is NaO
―B₂O₃―SiO₂—CaO-based ones;
l₂O₃, ZrO₂, ZnO₂, TiO₂, SnO₂,
MgO ₂Manufactured using glass to which various oxides are added.
It may be made. (This point is disclosed in JP-A-7-120350.
There is a description. )

The porous glass is, for example, silica sand, boric acid,
Mix soda ash and alumina, 1200-1400 ° C
Melts. After forming this at 800 to 1100 ° C., an unseparated borosilicate glass is obtained, and the SiO ₂ phase and B ₂
A phase is separated into an O ₃ —Na ₂ O—CaO phase, and an acid treatment is performed to produce a porous body having a SiO ₂ skeleton. By changing the conditions of the heat treatment depending on the application, the pore size can be uniform with a pore distribution of 0.1 to 10 μm depending on the application.

Examples of porous ceramics include silica,
Examples include alumina silicate A (sintered hard magnetic particles), silica sand, alumina, alumina silicate B (sintered chamotte particles), porous mullite, and diatomaceous earth. Porous ceramics include, for example, ceramic particles (hard magnetic pulverized material,
(Silica, alumina, chamotte, etc.) and a pore-forming material, for example, crystalline cellulose (Asahi Kasei: Avicel), and a suitable dispersing solvent, and are mixed, molded, and sintered. Pore diameter 500μ
Those having a range of about m to about 0.1 μm or more and having a uniform pore distribution can be manufactured according to the application.

The above-mentioned pores can be modified / modified on the surface of the pores by applying a coating agent and / or a chemical modifier suitable for a separation sample used in a conventional packing material. Examples of the coating agent include polyethylene glycol and silicone oil. As chemical modifiers, trimethylchlorosilane (TMS), dimethyl-
Examples include alkylsilanes such as n-octylchlorosilane and dimethyl-n-octadecylchlorosilane (ODS), aminoalkoxysilanes such as r-aminopropyltriethoxysilane, and various silane treatment agents such as epoxysilane. Furthermore, a high molecular compound such as a protein or a low molecular compound may be bonded to the modifying group of the surface modifying agent.

When a non-porous filler is packed in a column, pores are formed only between particles, and this is called a single pore. When silica gel particles having pores are packed in a column, the column has a double structure of pores in the particles and pores between the particles. This is called a double pore. When a non-porous filler is filled, it is a single pore, but the shape of the space changes depending on the state of the particles, and the separation mode becomes complicated. Further, separation by double pores does not result in simple adsorption distribution, and the separation mode is not simple. Therefore, a single pore in a state where the shape of the space does not change is recommended. This is the same for the porous body.

By filling part or all of the cavity 3 of the raw tube 1 with the above-mentioned porous body and other porous bodies, the flow of the atmosphere to the raw tube 1 can be made closer to laminar flow. Become. Examples of the porous body 5 include polyethylene, polypropylene, polyethylene terephthalate, urethane foam, silica, titania, zirconia, alumina, and hydroxyapatite in addition to the above.

A description will be given of a collecting process in the case where the gaseous component in the atmosphere is passively sampled by using the tubular collecting tube A having the above-described configuration. Outside the tube 1, there is no concentration gradient due to turbulence in the flow. However, the one end 11 of the tube 1 and the boundary layer outside the tube 1 have a resistance R against the flow of the measurement component into the tube 1.
_{There is one} . Next, in the cavity 3 serving as the diffusion controller, ideally, there is no turbulence and the flow is laminar, so that a concentration gradient exists. Flow by molecular diffusion to a resistance received when passing through this portion and R _2. Furthermore, the resistance R ₃ with the physical and chemical adsorption is present at the boundary between the porous body 2 and the cavity 3 as an adsorbent.

When the resistance value is defined as described above, the total
The mass transfer coefficient isK _OG = 1 / (R ₁+ R₂+ R₃)so
expressed. All measured components that have reached near the adsorbent are absorbed.
Assuming that₃= 0. Therefore depending on wind speed
K _OG To minimize the change in₂Is R₁Strange
Design the collection tube to obtain a sufficiently large value for the movement
do it.

[0019]

[Example 1] 10 ppm of benzene in the atmosphere was collected by a collection tube having a pipe diameter of 0.032 cm and a diffusion length of 1 cm.
Time sampling. Eight hours, 10 ppm is based on benzene, an indoor environmental guideline value set by the US Occupational Safety and Health Administration. Since the diffusion coefficient at 1 atm, 25 ° C. of benzene is ^{0.09 cm 2 / S, M =} D × (A / L) × (Ca-Cs) × t = 0.09 × (π × 0.016 2/1) × (10 × 10 ⁻⁶ × 10 ⁻³ × 3.49) × (8 × 3600) = 0.29 μg The amount of benzene trapped using this collection method and apparatus is 0.29 μg. This amount falls within the range of sensitivity of a flame ionization detector (FID), which is a general detection amount of a gas chromatograph, so that quantitative analysis is sufficiently possible. The relationship between the benzene concentration and the amount collected is shown in FIG.

[Table 1]

Example 2 Sample: 0.07 ppm of toluene (indicator of indoor concentration) in the atmosphere was sampled using the following collecting tube. Collection tube: Diffusion phase: Porous silica having a monolith structure with a through-pore of 50 μm Collector: ODS treatment of a porous silica having a monolith structure with a through-pore of 50 μm and a mesopore of 100 nm Overall mass transfer coefficient: K _OG = 0 0.0308 (cm / s) Collection time: 24 hours Since the overall mass transfer coefficient of the collection tube is K _OG = 0.0308 (cm / s), M = D × (A / L) × (Ca−Cs) × t = 0.0308 × (π × 0.016 2 /1)×(0.07×10 -6 × 10 -3 × 3.49) × (24 × 3 600) = 0.53μg are trapped using the collection method and apparatus The amount of benzene present is 0.53 μg. This amount falls within the range of sensitivity of a flame ionization detector (FID), which is a general detection amount of a gas chromatograph, so that quantitative analysis is sufficiently possible. The relationship between the toluene outside air concentration and the trapped amount is shown in FIG.

[Table 2]

Example 3 Benzene was measured in a working environment in an organic synthesis building in a factory. Collection tube: as a diffusion control unit of 0.032 cm, a cavity 1 cm from the end of the tube is provided on the inlet side, and a through-pore 50
A porous silica having a monolithic structure of 100 μm and a mesopore of 100 μm was formed by forming 2 cm of a collecting agent subjected to an ODS treatment and bundling seven tubes sealed at both ends. a. Open the sampling tube at the measurement point and start sampling. b. After 8 hours, the collection tube is sealed. c. Attach the collection tube to the heated desorption section connected to the gas chromatograph. d. Perform quantitative analysis under the following conditions. Device configuration: Injection port-(rapid heating unit + collection element tube)-GC
(FID) Separation column: TC. 1. Inner diameter 0.25mm, film thickness 0.1
μm, 15 m Inlet temperature: 120 ° C. Column temperature: 120 ° C., detector temperature: 120 ° C. Carrier gas: He, carrier pressure 150 kPa Rapid heating unit temperature program: 20 ° C. (3 minutes) -100 ° C.
/ S-120 ° C (10 minutes) e. Table 3 shows the results of analysis by GC-FID.

[Table 3] From this, the measured value was 60.1 (ppb / 8 hour average: N
= 7), and the CV value was 5.6%.

As described above, in the case where the target component is separated by a solvent, the target component is separated by a thin tube compared to a conventional passive sampler. Therefore, the solvent is small and the possibility of polluting the environment is reduced. The detachment by heating can be performed in a very easy and short operation time.

[0023]

Effects of the Invention According to the present invention, without using a power such as a motor, can be inexpensively manufactured in a very simple structure as a so-called passive sampler, increasing the number of measurements using a number simultaneously, the variation It is possible to provide an ideal sample adsorbing method and apparatus with low resistance to the adsorbent because of low aeration pressure loss and large surface area as a trapping agent.

According to the second aspect of the present invention, in addition to the above effects, when the sample reaches the adsorbent through the cavity in the tube, a diffusion control effect based on molecular diffusion of the substance to be measured is obtained. Overall mass transfer coefficient K _OG during the process of trapping the substance to be measured through the hollow part of the tube into the porous material (from the time the target substance moves from the atmosphere outside the column to the surface of the adsorbent inside the column and is collected) Has an effect of suppressing a change in the measurement environment (such as a temporal change in wind speed), and an error caused by measurement environment factors such as a change in wind speed during measurement can be suppressed.

According to the third aspect of the present invention, there is an effect that the overall mass transfer coefficient, which is the effect of the second aspect, is further stabilized, and the measured value is further stabilized. Furthermore, according to the fourth aspect, the extremely inexpensive and efficiently collected sample can be efficiently introduced into the analyzer as described above, and extremely efficient analysis of atmospheric substances has become possible.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a slope according to an embodiment of the present invention.

FIG. 2 is a schematic explanatory top view of another embodiment of the present invention.

FIG. 3 is a diagram illustrating the operation of the present invention.

FIG. 4 is a schematic perspective view illustrating another embodiment of the present invention.

FIG. 5 is a measurement diagram of one embodiment of the present invention.

FIG. 6 is a measurement diagram of another embodiment of the present invention.

[Description of Signs] 1 Raw tube 2 Porous body 3 Cavity 4 Cavity

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G052 AA01 AB07 AB08 AB12 AC02 AD02 AD22 AD42 BA05 BA21 DA09 EB11 ED06 ED07 ED11 GA27 JA03 JA09

Claims (4)

[Claims] 1. A method for collecting atmospheric substances such as gaseous substances in the atmosphere in a tube, wherein a collecting tube in which a porous body having an open structure made of an inorganic, organic or hybrid polymer is formed in a base tube. A simple method for trapping air pollutants. 2. An air substance characterized in that a porous body having an open structure made of an inorganic, organic or hybrid polymer is formed by placing an appropriate cavity from a pipe end in a part of a base tube as a collection tube. Simple collection device. 3. The simple atmospheric substance collecting apparatus according to claim 2, wherein a porous body having an open structure made of a substance that does not adsorb the measurement component is used in a cavity in the base tube of the collecting tube. 4. A gas component is collected using the simple method for collecting atmospheric substances according to claim 1, and then subjected to an appropriate extraction means such as solvent extraction or heat extraction, and then to an analysis device such as a chromatographic device. Analytical method for introducing trapped components