Adsorption column for collecting acidic or basic components in gases, and its use

Abstract

The present invention provides an adsorption column for collection that can quantify acidic or basic components in a gas quickly and with high sensitivity. [Solution] An adsorption column for collecting acidic or basic components in a gas is used, which is filled with a non-porous substrate that holds a basic adsorbent for adsorbing acidic components or an acidic adsorbent for adsorbing basic components, and has a pressure loss of 10 kPa or less when the gas inside is drawn out at a suction rate of 2.0 L / min.

Description

[Technical Field]

[0001] The present invention relates to an adsorption column for collecting acidic or basic components in a gas, and its use. Specifically, the use relates to a method for collecting acidic or basic components in a gas, a method for quantifying the concentration of acidic or basic components in a gas using the collection method, and a method for controlling the cleanliness of a cleanroom using the quantification method. [Background technology]

[0002] In environments where electronic substrates such as semiconductor wafers, liquid crystal substrates, and magnetic disks (hereinafter referred to as "substrates") are manufactured, contaminants such as acidic substances (acidic components) and basic substances (basic components) in the manufacturing space can be adsorbed onto the substrates, sometimes resulting in reduced product yield and quality. Therefore, to prevent such reductions in yield and quality, the manufacturing process for these substrates is carried out in a cleanroom. It is necessary to evaluate the level of contamination by the aforementioned acidic and basic substances in the cleanroom during each manufacturing process, in other words, the cleanliness level, and to manage the cleanliness of the cleanroom by removing the cause of contamination if the cleanliness level deteriorates. Furthermore, in recent years, there has been a demand for cleanrooms to provide a highly clean environment, and consequently, there is a need for methods to evaluate the level of contamination by acidic or basic components within the cleanroom, i.e., the cleanliness level, with higher sensitivity. Moreover, in recent years, there has been a demand to shorten the time required for the evaluation in order to simplify the management of cleanroom cleanliness.

[0003] As a method for evaluating the cleanliness with high sensitivity and in a short time, for example, a method of quantifying contaminants using a gas adsorption column described in Patent Documents 1 and 2, or a liquid-free trap described in Patent Document 3. Here, the contaminants refer to acidic and / or basic components in the air. Specifically, the method of quantifying the contaminants involves passing air from a cleanroom through the gas adsorption column or liquid-free trap to adsorb the contaminants in the air, and then quantifying the amount of adsorbed contaminants. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2009-14522 [Patent Document 2] International Publication No. 2010 / 067464 [Patent Document 3] Patent No. 6563396 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, the evaluation method using gas adsorption columns described in Patent Documents 1 and 2 had room for improvement in terms of the time required for evaluation. Furthermore, the evaluation method using liquid-free traps described in Patent Document 3 had room for improvement in terms of sensitivity.

[0006] The present invention has been made in view of the above matters, and the object of the present invention is to provide an adsorption column for collection that can be used for the rapid and highly sensitive quantitative determination of acidic or basic components in a gas, as well as a method for collecting and quantifying said acidic or basic components. Another object of the present invention is to provide a method for controlling the cleanliness of a space that can easily ensure a highly clean space. [Means for solving the problem]

[0007] To achieve the above objective, an adsorption column for collection according to one embodiment of the present invention is an adsorption column for collecting acidic or basic components in a gas, A non-porous substrate is filled in, The non-porous substrate holds a basic adsorbent for adsorbing acidic components or an acidic adsorbent for adsorbing basic components. The pressure loss when gas is drawn from the collection adsorption column at a suction rate of 2.0 L / min is 10 kPa or less. This is an adsorption column for collecting acidic or basic components in a gas.

[0008] Furthermore, in order to achieve the above objective, a collection method according to one embodiment of the present invention is a method for collecting acidic or basic components in a gas, which involves passing a gas through an adsorption column for collection according to one embodiment of the present invention to collect acidic or basic components in the gas.

[0009] Furthermore, in order to achieve the above objective, the quantitative method according to one embodiment of the present invention includes a collection step of collecting acidic or basic components in the gas using the collection method according to one embodiment of the present invention, An elution step is to pass a solvent through the collection adsorption column on which the acid component or the base component has been collected, thereby eluting the collected acid component or the base component into the solvent to obtain an eluate, and A method for quantifying the concentration of an acidic component or a basic component in a gas, comprising a measurement step of measuring the concentration of the acidic component or the basic component in the eluent.

[0010] In addition, in order to achieve the aforementioned other objective, the control method according to one embodiment of the present invention includes a quantitative step of quantifying the concentration of an acidic or basic component in a gas in a space using the quantitative method according to one embodiment of the present invention, and The method for controlling the cleanliness of a space includes a step of identifying and removing the source of the acidic or basic component in the gas inside the space when the concentration of the acidic or basic component quantified in the quantitative step exceeds a threshold. [Effects of the Invention]

[0011] According to the adsorption column for collection, the collection method, and the quantitative method according to one embodiment of the present invention, acidic or basic components in a gas can be quantified quickly and with high sensitivity. Furthermore, according to the method for controlling the cleanliness of a space according to one embodiment of the present invention, a highly clean space can be easily secured. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing the configuration of the quantitative apparatus used in Examples 4 and 5. [Modes for carrying out the invention]

[0013] One embodiment of the present invention is described below, but the present invention is not limited to the embodiments described later. The present invention can be modified in various ways within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0014] [Embodiment 1: Adsorption column for collection] An adsorption column for collection (hereinafter also referred to as "this adsorption column for collection") according to one embodiment of the present invention is an adsorption column for collecting acidic or basic components in a gas, wherein it is filled with a non-porous substrate, the non-porous substrate holds a basic adsorbent for adsorbing acidic components or an acidic adsorbent for adsorbing basic components, and the pressure loss when the gas in the adsorption column is drawn out at a suction rate of 2.0 L / min is 10 kPa or less.

[0015] In the following, since the adsorption column for collection filled with a non-porous substrate holding a basic adsorbent is a column for collecting acid components in a gas, it is also referred to as an "acid component adsorption column". Further, in the following, since the adsorption column for collection filled with a non-porous substrate holding an acidic adsorbent is a column for collecting basic components in a gas, it is also referred to as a "basic component adsorption column". The adsorption column for collection is either an acid component adsorption column or a basic component adsorption column.

[0016] (Non-porous substrate) The adsorption column for collection is filled with a non-porous substrate, and the non-porous substrate holds a basic adsorbent for adsorbing acid components or an acidic adsorbent for adsorbing basic components.

[0017] Here, generally, as the constituent substance of the adsorption component filled in the adsorption column for collection, from the viewpoint of ensuring the adsorption force for the target substance, a porous substance having a large surface area and the characteristic of being easily able to take in the substance to be adsorbed inside has been used. However, when quantifying the substance adsorbed on the adsorption column for collection, the adsorbed substance is desorbed and eluted into a solvent to prepare an eluate, and the eluate is quantified. The adsorption component composed of a porous substance has a strong adsorption force for the substance to be adsorbed, and when adsorbing an extremely small amount of substance, it is difficult to desorb the substance into the solvent. Therefore, in the quantification method using an adsorption column for collection filled with an adsorption component composed of a porous substance, it is considered that an extremely small amount of substance cannot be quantified.

[0018] Also, the adsorption component composed of a porous substance can also take in substances other than the substance to be adsorbed inside. Therefore, in the quantification method using an adsorption column for collection filled with an adsorption component composed of a porous substance, other substances other than the substance to be adsorbed, that is, other substances other than the substance to be quantified, are collected inside the adsorption column. As a result, the presence of the other substances becomes noise, and it is considered that an extremely small amount of substance cannot be quantified.

[0019] On the other hand, the non-porous substrate has weaker adsorption capacity to the substance to be adsorbed compared to the porous material, and even when adsorbing a very small amount of substance, the adsorbed substance can be easily desorbed into the solvent. Therefore, a quantitative method using this collection adsorption column can quantify a very small amount of substance.

[0020] Furthermore, this collection adsorption column is packed with a non-porous substrate, and the aforementioned other substances are not incorporated into this non-porous substrate. Therefore, the inability to quantify minute amounts of substances due to the presence of the aforementioned other substances is prevented. In this embodiment of the present invention, the substance to be quantified is an acidic or basic component in a gas.

[0021] As described above, this adsorption column for collection can collect and quantify acidic or basic components in a gas with high sensitivity. In this specification, "collecting and quantifying with high sensitivity" means, for example, determining the concentration of acidic or basic components in a gas at approximately 10 -2 μg / m 3 This means collecting and quantifying in that order.

[0022] The non-porous substrate can have any shape that does not have pores, and its material is not particularly limited. Examples of materials for the non-porous substrate include quartz, glass, polycarbonate resin, polystyrene resin, polyamide resin, silicon carbide (SiC), alumina (Al2O3), silicon nitride (SiN), etc. From the viewpoint of effectively preventing contamination of the non-porous substrate during use of the adsorption column for collection, the material of the non-porous substrate is preferably quartz or glass, and particularly preferably quartz.

[0023] The shape of the non-porous substrate is not particularly limited, but from the viewpoint of the adsorption column for collection suitably collecting acidic or basic components in the gas, a shape with a large surface area is preferred. Examples of shapes with a large surface area include particulate and fibrous shapes. The shape of the non-porous substrate is more preferably particulate.

[0024] The lower limit of the average particle size or average cross-sectional diameter of the nonporous substrate is preferably 300 μm or more, more preferably 400 μm or more, even more preferably 450 μm or more, even more preferably 500 μm or more, and particularly preferably 600 μm or more, from the viewpoint of improving the efficiency of aeration to the adsorption column for collection. The upper limit of the average particle size or average cross-sectional diameter of the nonporous substrate is preferably 1200 μm or less, more preferably 1100 μm or less, even more preferably 1050 μm or less, even more preferably 1000 μm or less, and particularly preferably 850 μm or less, from the viewpoint of improving the efficiency of collecting the acid or base components into the adsorption column for collection. The method for measuring the average particle size and average cross-sectional diameter in this case is in accordance with JIS K0069 "Test Method for Sieving Chemical Products".

[0025] The basic adsorbent is an adsorbent for adsorbing acidic components, and specifically may consist of or contain a basic substance. The acidic adsorbent is an adsorbent for adsorbing basic components, and specifically may consist of or contain an acidic substance.

[0026] In one embodiment of the present invention, the acid component is not particularly limited. Examples of the acid component include acids themselves such as hydrogen chloride, nitric acid, sulfuric acid, phosphoric acid, hydrofluoric acid, formic acid, acetic acid, bromate, iodine, lactic acid, propionic acid, butyric acid, and valeric acid, as well as ammonium fluoride, ammonium formate, and ammonium acetate. Furthermore, in one embodiment of the present invention, the base component is not particularly limited. Examples of the base component include bases themselves such as ammonia, trimethylamine, triethylamine, alkanolamine, dimethylamine, and diethylamine, as well as ammonium fluoride, ammonium formate, and ammonium acetate.

[0027] The amount of the basic adsorbent or the acidic adsorbent in the collection adsorption column is preferably 0.4 μeq or more, more preferably 0.7 μeq or more, and even more preferably 0.8 μeq or more. Adjusting the amount of the basic adsorbent or the acidic adsorbent to 0.4 μeq or more is preferable in that it prevents column breakthrough when collecting high concentrations of gas. On the other hand, the amount of the basic adsorbent or the acidic adsorbent is preferably 50 μeq or less, more preferably 30 μeq or less, and even more preferably 20 μeq or less. Adjusting the amount of the basic adsorbent or the acidic adsorbent to 50 μeq or less is preferable in that it prevents measurement inhibition by excess adsorbent components. The amount of the basic adsorbent or the acidic adsorbent is expressed as an equivalent value and can be measured by the method described in the examples.

[0028] Examples of the basic adsorbent include inorganic bases and organic bases. Examples of the inorganic base include alkali metal carbonates and alkali metal hydroxides. Examples of the organic base include amines and ammonium compounds.

[0029] The basic adsorbent is preferably at least one compound selected from the group consisting of alkali metal carbonates, alkali metal hydroxides, amines, and ammonium compounds among the compounds listed above.

[0030] Examples of alkali metal carbonates include sodium carbonate, potassium carbonate, and potassium bicarbonate. Examples of alkali metal hydroxides include strontium hydroxide, potassium hydroxide, and sodium hydroxide. Examples of amines include triethanolamine. Examples of ammonium compounds include tetramethylammonium hydroxide and tetrabutylammonium hydroxide.

[0031] The basic adsorbent is more preferably at least one compound selected from the group consisting of sodium carbonate, sodium hydroxide, and triethanolamine.

[0032] Examples of the aforementioned acidic adsorbent include inorganic acids and organic acids.

[0033] Examples of the inorganic acid include sulfuric acid and phosphoric acid. Examples of the organic acid include methanesulfonic acid, maleic acid, and malonic acid.

[0034] The acidic adsorbent is preferably at least one compound selected from the group consisting of sulfuric acid, phosphoric acid, and methanesulfonic acid among the compounds listed above.

[0035] In one embodiment of the present invention, the form in which the non-porous substrate holds the basic adsorbent or the acidic adsorbent is not particularly limited. For example, the form may be such that the solid basic adsorbent or the acidic adsorbent is attached to the surface of the non-porous substrate, or the non-porous substrate may be covered with a liquid phase containing the basic adsorbent or the acidic adsorbent.

[0036] The liquid phase is a liquid containing the basic adsorbent or the acidic adsorbent, and optionally contains a solvent. In other words, if the basic adsorbent or the acidic adsorbent is a solid, the liquid phase can be prepared by dissolving the basic adsorbent or the acidic adsorbent in a solvent. The solvent is not particularly limited and can be any solvent that can dissolve the basic adsorbent or the acidic adsorbent and does not adversely affect the non-porous substrate. Specific examples of the solvent include water, hydrogen peroxide, ethanol, acetonitrile, or mixtures thereof. The solvent is preferably a water-containing solvent, such as a mixture of water and a solvent other than water from the specific examples of the solvents listed above, and more preferably a solvent consisting only of water. On the other hand, if the basic adsorbent or the acidic adsorbent is a liquid, the basic adsorbent or the acidic adsorbent can be used as is as the liquid phase.

[0037] In one embodiment of the present invention, the method for covering the non-porous substrate with the liquid phase is not particularly limited. Examples of such methods include coating the non-porous substrate with the liquid phase, and immersing the non-porous substrate in the liquid phase, then removing the non-porous substrate and drying it. A specific example of the method for coating the non-porous substrate with the liquid phase is coating it by passing the liquid phase through the porous substrate. Here, "passing through" means passing the liquid phase through a container, such as a column, in which the porous substrate is filled. If the drying conditions are high temperature and long duration, the solvent in the liquid phase may evaporate, and the solid basic adsorbent or acidic adsorbent may precipitate on the surface of the non-porous substrate. In that case, the non-porous substrate can be obtained in a form in which the solid basic adsorbent or acidic adsorbent is attached to the surface.

[0038] In one embodiment of the present invention, the non-porous substrate may further retain a humectant. In the non-porous substrate that further retains a humectant, if the basic adsorbent or the acidic adsorbent is retained in the form of a liquid phase, the liquid phase may further contain the humectant. Examples of the humectant include polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin; and polyalkylene glycols such as polyethylene glycol and polypropylene glycol. The content of the humectant may be 0.01% by weight or more and 1.0% by weight or less, and preferably 0.1% by weight or more and 0.5% by weight or less, based on the total weight of the non-porous substrate covered with the liquid phase.

[0039] (Composition of the adsorption column for collection) The adsorption column for collection may consist of a housing (i.e., an outer casing) and a frit, which is a filter placed inside the housing to prevent the non-porous substrate from flowing out. The materials of the housing and the frit are not particularly limited, as long as they do not affect the acidic or basic components to be collected and are not adversely affected by the basic or acidic adsorbent. Examples of materials for the housing include polypropylene, glass, polyethylene (PE), polyetheretherketone (PEEK), polyvinyl chloride (PVC), polystyrene (PS), ABS resin (ABS), methacrylic resin, acrylic resin (PMMA), polyamide (PA), polyacetal (POM), polycarbonate (PC), modified polyphenylene ether (mPPE), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polysulfone (PSU), polyarylate (PAR), fluororesin (PFA), and mixtures thereof. Examples of materials for the frit include polyethylene, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyethersulfone (PES), cellulose, glass fiber, carbon fiber, diatomaceous earth, cellulose, polyethylene terephthalate (PET), nylon, and mixtures thereof. The materials of the housing and the frit may be the same type or different types.

[0040] The shape of the adsorption column for collection is not particularly limited, and a cylindrical shape can usually be used. Preferably, the adsorption column for collection consists of a column body, frit, sleeve, and end fittings, and an example of the one described in Japanese Patent Application Publication No. 2001-249120 can be cited.

[0041] The internal volume of this adsorption column for collection (the internal volume of the housing) can be of an appropriate size depending on the analytical processing volume. For example, the volume may be 0.6 ml to 5 ml, 0.6 ml to 3 ml, or 0.7 ml to 2 ml.

[0042] The void volume of the adsorption column for collection refers to the volume of gaps in the adsorption column that are not filled with the non-porous substrate covered by the liquid phase. The void volume can be measured, for example, by the method described in the examples. The larger the void volume, the greater the amount of gas that passes through the adsorption column per unit time, i.e., the air permeability, when collecting acidic or basic components in a gas. When performing quantitative analysis using the adsorption column for collection, a predetermined amount of gas is collected into the adsorption column for collection, passed through, and the acidic or basic components contained in the predetermined amount of gas are collected. Therefore, the larger the void volume, the shorter the time required to collect and pass a predetermined amount of gas through the adsorption column for collection. Consequently, with the adsorption column for collection, the larger the void volume, the faster the acidic or basic components in a gas can be collected and quantified.

[0043] From the viewpoint of quantifying acidic or basic components in a gas using this collection adsorption column in a shorter time, the void volume is preferably 200 μL or more, more preferably 300 μL or more, and even more preferably 400 μL or more.

[0044] On the other hand, when the void volume is less than or equal to a predetermined value, the amount of non-porous substrate holding the basic adsorbent or acidic adsorbent packed in the adsorption column for collection is sufficiently large, and the ability to collect acidic or basic components in the gas can be sufficiently ensured. From this perspective, the adsorption column for collection can collect and quantify acidic or basic components in the gas with higher sensitivity. From the viewpoint of collecting and quantifying acidic or basic components in the gas with higher sensitivity, the void volume is preferably 5000 μL or less, more preferably 3000 μL or less, even more preferably 600 μL or less, and particularly preferably 500 μL or less.

[0045] The porosity of the adsorption column for collection can be defined as "porosity (%) = void volume ÷ internal volume of the adsorption column for collection × 100". In this case, the lower limit of the porosity of the adsorption column for collection is not limited and may be, for example, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, or 70% or more. On the other hand, the upper limit of the porosity of the adsorption column for collection is not limited and may be, for example, 90% or less, 80% or less, or 70% or less. The above configuration is preferable in that it can sufficiently exhibit the effect of preventing a decrease in the suction rate during air collection due to a low porosity while not reducing the amount of acidic or basic components adsorbed onto the adsorbent.

[0046] This adsorption column has an upper limit of 10 kPa or less in pressure loss when gas is drawn into the column at a suction rate of 2.0 L / min. Hereinafter, the pressure loss when drawn at a suction rate of 2.0 L / min will be referred to as "pressure loss A". As mentioned above, when performing quantitative analysis using this adsorption column, it is necessary to collect a predetermined amount of gas, pass it through the column, and collect the acidic or basic components contained in that predetermined amount of gas. Because pressure loss A is 10 kPa or less, when collecting and passing the gas to be measured through the adsorption column for quantitative analysis, it is possible to collect gas at high speed without putting a load on the suction pump used for collection. Therefore, a predetermined amount of gas can be collected and passed through the adsorption column in a short time. Accordingly, this adsorption column allows for the collection and quantification of acidic or basic components in a gas in a short time.

[0047] From the viewpoint of quantifying acidic or basic components in a gas in a short time using this collection adsorption column, the upper limit of the pressure drop A is preferably 7 kPa or less, and more preferably 5 kPa or less.

[0048] [Embodiment 2] A collection method according to one embodiment of the present invention (hereinafter also referred to as "this collection method") is a method for collecting acidic or basic components in a gas, which involves passing a gas through this collection adsorption column to collect acidic or basic components in the gas.

[0049] This collection method uses a collection adsorption column to collect acidic or basic components from a gas. As mentioned above, this collection adsorption column can collect trace amounts of acidic or basic components from a gas in a short time. Therefore, this collection method enables a quantitative analysis that can collect and quantify acidic or basic components from a gas quickly and with high sensitivity.

[0050] Hereinafter, the collection method that uses an acid component adsorption column to collect the concentration of acid components in a gas will also be referred to as the "acid component collection method." Furthermore, the collection method that uses a base component adsorption column to collect the concentration of base components in a gas will also be referred to as the "base component collection method." This collection method is either an acid component collection method or a base component collection method.

[0051] The configuration of the adsorption column used in this collection method is based on the configuration described in [Embodiment 1: Adsorption Column for Collection]. Furthermore, the acidic and basic components to be quantified in this collection method are not particularly limited and may be the acidic and basic components exemplified in the section [Embodiment 1: Adsorption Column for Collection] above.

[0052] Here, both the acid component collection method and the base component collection method can be carried out simultaneously on the same gas to collect both the acid and base components in the gas.

[0053] In this collection method, the gas to be collected is passed through this collection adsorption column, and the acidic or basic components in the gas are collected by adsorption onto a non-porous substrate on which the acidic component adsorbent or basic component adsorbent is held. This aeration is usually performed using a suction pump.

[0054] In this collection method, by passing the gas through an adsorption column for collecting acidic or basic components in the gas at a higher flow rate, the time required to collect the acidic or basic components in the collection step can be shortened. As a result, this collection method allows for the collection and quantification of acidic or basic components in the gas in a short time. From the viewpoint of collecting and quantifying acidic or basic components in the gas in a short time, the flow rate is preferably 2.0 L / min or higher, more preferably 3.0 L / min or higher. On the other hand, if the flow rate is excessively high, the pressure applied to the adsorption column for collection when passing the gas through will increase, which may damage the adsorption column. From the viewpoint of effectively preventing damage to the adsorption column for collection, the flow rate is preferably 10 L / min or less, more preferably 7 L / min or less. From the viewpoint of being superior in both the time required for quantitative determination and in preventing damage, the airflow velocity is particularly preferably 5 L / min.

[0055] The aforementioned ventilation of the adsorption column for analyte collection is typically performed in the space being evaluated, such as a cleanroom or clean booth. The adsorption column for analyte collection is transported by sealing the opening of the adsorption column with a stopper that is free from contamination of the analyte, and / or by placing the adsorption column in a sealed container that is free from contamination of the analyte.

[0056] When performing both an acid component collection method and a base component collection method, an apparatus equipped with a configuration in which an acid component adsorption column and a base component adsorption column are arranged in series may be used to continuously perform both the acid component collection method and the base component collection method. That is, the apparatus may be used to draw in air, and the air may be continuously passed through both the acid component adsorption column and the base component adsorption column constituting the apparatus. More specifically, (i) the air that has passed through the acid component adsorption column may be passed through the base component adsorption column, or (ii) the air that has passed through the base component adsorption column may be passed through the acid component adsorption column. In this case, the acid component adsorption column and the base component adsorption column may be directly connected, or they may be connected via a connecting tube.

[0057] [Embodiment 3: Quantitative Method] A quantitative method according to one embodiment of the present invention (hereinafter also referred to as "this quantitative method") is a method for quantifying the concentration of an acidic or basic component in a gas, comprising: a collection step of collecting an acidic or basic component in the gas using this collection method; an elution step of passing a solvent through the collection adsorption column from which the acidic or basic component has been collected, thereby eluting the collected acidic or basic component into the solvent to obtain an eluate; and a measurement step of measuring the concentration of the acidic or basic component in the eluate.

[0058] This quantitative method uses the collection method with the collection adsorption column to collect and quantify acidic or basic components in a gas. As described above, the collection adsorption column and collection method allow for the collection and quantification of acidic or basic components in a gas in a short time and with high sensitivity. Therefore, this quantitative method also allows for the collection and quantification of acidic or basic components in a gas in a short time and with high sensitivity.

[0059] Hereinafter, the quantitative method for determining the concentration of acidic components in a gas using an acidic component adsorption column will also be referred to as the "acidic component quantitative method." Furthermore, the quantitative method for determining the concentration of basic components in a gas using a basic component adsorption column will also be referred to as the "basic component quantitative method." This quantitative method is either an acidic component quantitative method or a basic component quantitative method.

[0060] The configuration of the adsorption column used for collection in this quantitative analysis method is based on the configuration described in [Embodiment 1: Adsorption Column for Collection]. Furthermore, the acidic and basic components to be quantified in this quantitative analysis method are not particularly limited and may be the acidic and basic components exemplified in the [Embodiment 1: Adsorption Column for Collection] section above.

[0061] Here, both the acid component quantification method and the base component quantification method can be performed on the same gas to quantify both the acid and base components in the gas together. Furthermore, this quantification method can be performed offline, in which the collection and elution steps described later are carried out without the collection adsorption column being connected to a measuring device that measures the concentration of acid or base components in the eluate.

[0062] (Collection process) This quantitative method includes a collection step of collecting acidic or basic components in the gas using the collection method described herein. The configuration of the collection method used in the collection step is as described in [Embodiment 2: Collection Method].

[0063] When performing both an acid component quantification method and a base component quantification method, the collection steps for each method may be performed simultaneously, in the same manner as when performing both the acid component collection method and the base component collection method described above. That is, air may be drawn into an apparatus having a configuration in which an acid component adsorption column and a base component adsorption column are arranged in series, and the air may be simultaneously passed through both the acid component adsorption column and the base component adsorption column constituting the apparatus. After that, the acid component adsorption column and the base component adsorption column may be separated from the apparatus, and the elution step and measurement step described later may be performed for each.

[0064] (Elution process) This quantitative method includes an elution step in which a solvent is passed through the adsorption column for collection, which has collected the acidic component or the basic component, to elute the collected acidic component or the basic component into the solvent and obtain an eluate.

[0065] In the elution step, the acid component or base component collected by the collection adsorption column is eluted into the solvent, and as a result, an eluate containing the acid component or base component is obtained. The solvent is not particularly limited as long as it is a solvent that can elute the acid component or base component. As the solvent, from the viewpoint of the sensitivity of this quantitative method, it is preferable to use a solvent that does not contain impurities that may cause a decrease in sensitivity, or has an extremely low content of such impurities. From this viewpoint, it is particularly preferable to use pure water as the solvent. Here, pure water means water whose electrical resistivity is in the range of 0.1 MΩ·cm or more and 18 MΩ·cm or less.

[0066] (Measurement process) This quantitative method includes a measurement step of measuring the concentration of the acid component or the base component in the eluate.

[0067] The acidic or basic component in the eluate is the same acidic or basic component in the gas collected in the collection step. Therefore, the concentration of the acidic or basic component in the eluate measured in the measurement step corresponds to the concentration of the acidic or basic component in the gas. Thus, the concentration of the acidic or basic component in the gas can be quantified by the measurement step.

[0068] The method for measuring the concentration of the acid component or the base component in the eluate (hereinafter also referred to as "the measurement method") can be a known method and is not particularly limited. The measurement method may be, for example, a liquid chromatography method. Examples of the liquid chromatography method include an anion exchange method using an ion exchange column, a cation exchange method, and a suppressor-type ion chromatography method using a suppressor.

[0069] The acidic component exists as anions in the eluate, and the basic component exists as cations in the eluate. Therefore, the total concentration of anions in the eluate can be measured by the method described above, and the resulting concentration can be taken as the concentration of the acidic component. Similarly, the total concentration of cations in the eluate can be measured by the method described above, and the resulting concentration can be taken as the concentration of the basic component.

[0070] [Embodiment 4: Method for controlling the cleanliness of a space] A method for controlling the cleanliness of a space according to one embodiment of the present invention (hereinafter also referred to as "this control method") is a method for controlling the cleanliness of a space, comprising: a quantitative step of quantifying the concentration of an acidic component or a basic component in a gas within a space using this quantitative method; and a step of identifying and removing the source of the acidic component or basic component in the gas inside the space when the concentration of the acidic component or basic component quantified in the quantitative step exceeds a threshold.

[0071] According to this management method, the concentration of acidic or basic components, which are pollutants in the space, is quantified quickly and with high sensitivity in the quantification step. Then, if the quantified concentration of acidic or basic components exceeds a specific threshold, the process proceeds to identify and eliminate the source of the acidic or basic components in the gas inside the space.

[0072] Since the quantitative analysis can be performed with high sensitivity, the predetermined threshold can be set to a low value in this management method. Therefore, by setting the predetermined threshold to a low value, this management method makes it possible to identify and eliminate the source of contamination at a stage when the amount of the acidic or basic component contaminant is small, and as a result, a highly clean space can be secured. Furthermore, since the quantitative analysis can be performed in a short time, the time from the start of the quantitative analysis to the completion of identification and elimination of the source of contamination can be shortened, and as a result, a highly clean space can be easily secured. For this reason, this management method makes it easy to secure a highly clean space. In this specification, "source of contamination" means "the source of the acidic or basic component in the gas inside the space."

[0073] (Quantitative process) This control method includes a quantitative step of quantifying the concentrations of acidic and basic components in a gas within a space using this quantitative method. By performing the quantitative step, the concentrations of acidic and basic components, which are pollutants in the gas within a space, can be easily quantified.

[0074] The space referred to in this specification is the space to be evaluated using the aforementioned collection adsorption column for quantitative analysis, etc., and may be, for example, a space where the concentrations of the acidic and basic components as contaminants must be below a specific threshold for use in operations such as the manufacture of electronic circuit boards. The space referred to in this control method may be a space having a predetermined volume formed by walls, floors, etc. The space is not particularly limited and can be, for example, a clean room, a clean booth, or the space inside a manufacturing apparatus.

[0075] The configuration of the quantitative method in the aforementioned quantitative process shall be based on the configuration described in [Embodiment 3: Quantitative Method] above.

[0076] In this management method, in order to ensure a highly clean space, the amount (concentration) of the acidic and / or basic components, which are pollutants in the gas within the space, is quantified. Then, based on the quantified concentration, the source of contamination is identified and excluded. Therefore, in the quantification step, either the acidic component quantification method or the basic component quantification method may be performed, or the acidic component quantification method and the basic component quantification method may be performed simultaneously, but it is preferable to perform the acidic component quantification method and the basic component quantification method simultaneously. In order to perform these simultaneously, it is preferable to use an apparatus equipped with a configuration in which the aforementioned acidic component adsorption column and basic component adsorption column are arranged in series. When using such an apparatus, since air can be passed through both the acidic component adsorption column and the basic component adsorption column constituting the apparatus with a single suction, the quantification step and this management method can be easily implemented.

[0077] (The process of identifying and eliminating the source of contamination) This management method includes a step of identifying and eliminating the source of contamination when the concentration of the acidic or basic component quantified in the quantitative step exceeds a threshold. By performing this step, the concentration of the acidic or basic component contaminant within the space can be controlled to below the threshold, thereby ensuring a highly clean space.

[0078] The threshold value in the aforementioned process can be appropriately determined based on the type of operation performed in the space and the quality required for the product manufactured by that operation, and is not particularly limited. For example, when manufacturing high-quality electronic substrates in the space, the threshold value is 1.0 μg / m 3 , 0.1 μg / m 3 Or 0.01 μg / m 3 These are possible.

[0079] Identifying and eliminating the aforementioned source of contamination means determining the concentrations of the acidic and basic components, which are contaminants, within the space and taking corresponding actions. The specific method for doing so is not particularly limited, and known methods can be employed.

[0080] One embodiment of the present invention may be the inventions shown in [1] to [7] below. [1] An adsorption column for collecting acidic or basic components in a gas, A non-porous substrate is filled in, and the non-porous substrate holds a basic adsorbent for adsorbing acidic components or an acidic adsorbent for adsorbing basic components. The pressure loss when gas is drawn from the collection adsorption column at a suction rate of 2.0 L / min is 10 kPa or less. Adsorption column for collecting acidic or basic components in gases. [2] The collection adsorption column according to [1], wherein the void volume of the collection adsorption column is 200 μL or more and 3000 μL or less. [3] The collection adsorption column according to [1] or [2], wherein the amount of the basic adsorbent or the acidic adsorbent is 0.4 μeq or more and 50 μeq or less. A method for collecting acidic or basic components in a gas, comprising passing a gas through an adsorption column for collection described in any one of [1] to [3], thereby collecting the acidic or basic components in the gas. [5] The collection method according to [4], wherein the gas is passed through the adsorption column for collection at an airflow rate of 2.0 L / min or more. A collection step of collecting acidic or basic components in the gas using the collection method described in [6], [4] or [5], An elution step is to pass a solvent through the collection adsorption column on which the acid component or the base component has been collected, thereby eluting the collected acid component or the base component into the solvent to obtain an eluate, and A method for determining the concentration of an acidic component or a basic component in a gas, comprising a measurement step of measuring the concentration of the acidic component or the basic component in the eluent. A quantitative step of quantifying the concentration of an acidic or basic component in a gas in a space using the quantitative method described in [7][6], and A method for controlling the cleanliness of a space, comprising the step of identifying and removing the source of the acidic or basic component in the gas inside the space when the concentration of the acidic or basic component quantified in the quantitative step exceeds a threshold. [Examples]

[0081] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0082] [Measurement method] The method for measuring the physical properties of the adsorption column used for collection, as described in the examples, is shown below.

[0083] (weight) In this embodiment, the weight of the adsorption column for collection was measured using a weighing scale (manufacturer: Mettler Toledo Co., Ltd., product name: Electronic non-automatic scale PB3003-L).

[0084] (void volume) The adsorption column for collection described in the example was dried by passing compressed air through it at a flow rate of 2 L / min for 17 hours. The weight of the dried adsorption column was measured. The measured value is denoted as W0 (g). Subsequently, pure water at room temperature was introduced into the dried adsorption column, filling the column with the pure water. The weight of the adsorption column filled with the pure water was measured. The measured value is denoted as W1 (g). Here, the density of the pure water is assumed to be 1 g / cm³. 3 The void volume of the adsorption column for collection was then determined. Specifically, assuming that the void volume was the same as the weight W2 (g) of pure water packed into the adsorption column for collection, the void volume was calculated based on the following formula (1). Empty volume of adsorption column for collection (cm 3 ) = W2(g) = W1(g) - W0(g) ... (1) (Equivalent amounts of basic adsorbent and acidic adsorbent contained in the acid component adsorption column) 10 mL of pure water was passed through the acid component adsorption column described in the example to elute the basic adsorbent in the acid component adsorption column and obtain the first eluate. Subsequently, 40 mL of pure water was passed through the acid component adsorption column after the 10 mL of pure water had been passed through it to elute the basic adsorbent in the acid component adsorption column and obtain the second eluate. Both the first and second eluates were subjected to ion chromatography, and the equivalent amount of basic adsorbent contained in each eluate was measured. The sum of the equivalent amounts of basic adsorbent contained in each measured eluate was taken as the equivalent amount of basic adsorbent contained in the acid component adsorption column.

[0085] Similarly, 10 mL of pure water was passed through the basic component adsorption column described in the example to elute the acidic adsorbent in the basic component adsorption column and obtain the first eluate. Subsequently, 40 mL of pure water was passed through the basic component adsorption column after the 10 mL of pure water had been passed through it to elute the acidic adsorbent in the basic component adsorption column and obtain the second eluate. Both the first and second eluates were subjected to ion chromatography, and the equivalent amount of acidic adsorbent contained in each eluate was measured. The sum of the equivalent amounts of acidic adsorbent contained in each measured eluate was taken as the equivalent amount of acidic adsorbent contained in the basic component adsorption column.

[0086] (Pressure loss) A gas suction pump was connected to the adsorption column for collection described in the example, and suction was performed at a rate of 2.0 L / min. The pressure loss at that time was measured with a differential pressure gauge. In this example, the gas suction pump used was the Mini Pump-MP MP-Σ300, manufactured by Shibata Scientific Co., Ltd., which was used for the measurement of the pressure loss and in Examples 3 to 5 described below.

[0087] (Ion chromatograph) The measurement methods using ion chromatography, which were used to measure the equivalent amounts of the basic and acidic adsorbents shown above, as well as the amount of anions and cations attached as described in Examples 3 to 5 below, were as follows.

[0088] The eluate was analyzed using an ion chromatography system equipped with electrolysis suppression and electrical conductivity detection. The anion channel of the ion chromatography system uses a potassium hydroxide (KOH) eluent gradient and an inorganic anion and organic acid anion analysis column. The cation channel of the ion chromatography system uses a methanesulfonic acid eluent gradient and a cation analysis column.

[0089] [Example 1: Production of an acid component adsorption column] 0.9 g of quartz particles with a particle size of 0.5 mm to 1.0 mm were filled into a cylindrical column housing made of polypropylene with an internal volume of 0.92 mL. After passing methanol through, ultrapure water (specific resistance 18 MΩ·cm) was passed through the column for cleaning.

[0090] After passing a mixed aqueous solution of sodium carbonate and glycerin through the column after the above cleaning, clean air was passed through for drying to produce an acid component adsorption column.

[0091] The physical properties of the produced acid component adsorption column were measured by the above method. As a result, in the acid component adsorption column, the void volume was 0.44 cm 3 , the equivalent amount of the adsorbent contained was 1.80 μeq, and the pressure loss when suction was performed at a suction rate of 2.0 L / min was 2.73 kPa.

[0092] [Example 2: Production of a base component adsorption column] 0.9 g of quartz particles with a particle size of 0.5 mm to 1.0 mm were filled into a cylindrical column housing made of polypropylene with an internal volume of 0.92 mL. After passing methanol through, ultrapure water (specific resistance 18 MΩ·cm) was passed through the column for cleaning.

[0093] After passing a mixed aqueous solution of sulfuric acid and glycerin through the column after the above cleaning, clean air was passed through for drying to produce a base component adsorption column.

[0094] The physical properties of the produced base component adsorption column were measured by the above method. As a result, in the base component adsorption column, the void volume was 0.44 cm 3 , the equivalent amount of the adsorbent contained was 1.01 μeq, and the pressure loss when suction was performed at a suction rate of 2.0 L / min was 2.70 kPa.

[0095] [Example 3: Elution of a collection adsorption column that collected air inside a clean booth] The acid component adsorption column prepared in Example 1 and the base component adsorption column prepared in Example 2 were each connected to a gas suction pump, and air from a clean booth in the laboratory was passed through them at a suction rate of 2.0 L / min for 5 hours.

[0096] After the aeration process, ultrapure water was passed through the acid component adsorption column and the base component adsorption column at a rate of 2 mL / min for 5 minutes to obtain eluates containing anions and cations, i.e., acid and base components, from the columns. The obtained eluates were subjected to ion chromatography, and the concentrations (in ng / mL) of anions and cations, i.e., acid and base components, in the eluate were measured. The limit of quantification was also determined from the results of the same procedure performed without sampling air. The measured limit of quantification and the concentrations of acid and base components in the eluate are shown in Table 1. In Table 1, the acid component adsorption column is referred to as "Column A," and the base component adsorption column is referred to as "Column B." The concentrations of acid and base components in the eluate are simply referred to as "Concentration in Elutate."

[0097] [Table 1]

[0098] [Example 4: Analysis results of air inside the clean booth] A quantitative analysis device was fabricated with the configuration shown in Figure 1. Specifically, the acid component adsorption column 1 manufactured in Example 1 and the base component adsorption column 2 manufactured in Example 2 were connected via a connecting tube 4, and the opposite end of the base component adsorption column 2 from the side connected to the acid component adsorption column 1 was connected to a suction pump 3 to create the quantitative analysis device.

[0099] The side of the acid component adsorption column 1 in the aforementioned quantitative apparatus that is connected to the base component adsorption column 2 is connected to a clean booth equipped with a chemical filter. Subsequently, using a suction pump 3, air was drawn through both the acid component adsorption column 1 and the base component adsorption column 2 at a flow rate of 2 L / min for 5 hours. After the airflow, 10 mL of pure water was passed through each of the acid component adsorption column 1 and the base component adsorption column 2 to obtain eluates (4a) and (4b). Elutates (4a) and (4b) were subjected to ion chromatography, and the concentrations of anions, i.e., acid components, in eluate (4a) and cations, i.e., base components, in eluate (4b) were quantified. The concentrations of acid and base components in the air inside the clean booth were calculated by multiplying the quantified concentrations in the obtained eluates (4a) and (4b) by the amount of eluate and dividing by the amount of air sampled. Furthermore, the limit of quantification was calculated from the results of performing the same procedure without collecting air samples. The calculation of each concentration and the limit of quantification was repeated twice, and the average of the two calculated values ​​was used as the respective concentration and limit of quantification.

[0100] The calculated limit of quantification and the concentrations of acidic and basic components within the clean booth are shown in Table 2 below. Similar to Table 1, in Table 2, the acidic component adsorption column is referred to as "Column A," and the basic component adsorption column is referred to as "Column B." Furthermore, in Table 2, the concentrations of acidic and basic components within the clean booth are simply referred to as "Concentration within the clean booth."

[0101] [Table 2]

[0102] [Example 5: Results of periodic analysis of air inside a clean booth] For each clean booth immediately after startup, and one month, two months, and three months after startup, the concentrations of acidic and basic components in the air within the clean booth, as well as the limit of quantification, were calculated using the same method as in Example 4.

[0103] The calculated limit of quantification and the concentrations of acidic and basic components within the clean booth are shown in Table 3 below. Similar to Table 2, in Table 3, the acidic component adsorption column is referred to as "Column A," the basic component adsorption column as "Column B," and the concentrations of acidic and basic components within the clean booth are simply referred to as "Clean Booth Concentration."

[0104] [Table 3]

[0105] [result] As shown in Examples 1 and 2, the adsorption columns for collection manufactured in Examples 1 and 2 satisfy the following requirements (i) to (iii), and therefore qualify as adsorption columns for collection. (i) It is filled with a non-porous substrate. (ii) The non-porous substrate holds a basic adsorbent for adsorbing acidic components or an acidic adsorbent for adsorbing basic components. (iii) The pressure loss when the gas in the collection adsorption column is drawn out at a suction rate of 2.0 L / min is 10 kPa or less.

[0106] Furthermore, based on the descriptions in Examples 4 and 5, the methods for collecting acidic and basic components in Examples 4 and 5 involve passing a gas through the adsorption column for collection to collect acidic or basic components in the gas, and therefore correspond to the collection method described herein.

[0107] Furthermore, based on the descriptions in Examples 4 and 5, the quantitative determination methods for acidic and basic components in Examples 4 and 5 are methods for determining the concentration of acidic or basic components in a gas, including the following steps (iv) to (vi), and therefore correspond to the present quantitative determination method. (iv) A collection step of collecting acidic or basic components in the gas using the collection method. (v) An elution step of passing a solvent through the collection adsorption column from which the acidic or basic components have been collected, thereby eluting the collected acidic or basic components into the solvent to obtain an eluate. (vi) A measurement step of measuring the concentration of the acid component or the base component in the eluate.

[0108] Furthermore, the descriptions in Examples 3 to 5 and Tables 1 to 3 demonstrate that the collection and quantification methods using the collection adsorption columns manufactured in Examples 1 and 2 can collect and quantify acidic and basic components with high sensitivity, even with a short aeration time of 5 hours. Similarly, the descriptions in Examples 4 and 5 and Tables 2 and 3 demonstrate that the collection and quantification methods in Examples 4 and 5 can collect and quantify acidic and basic components with high sensitivity, even with a short aeration time of 5 hours.

[0109] Therefore, it was found that the present adsorption column, collection method, and quantitative method can collect and quantify acidic or basic components in a gas in a short time and with high sensitivity. Furthermore, it was found that the control method using the present adsorption column and quantitative method can identify and remove the source of the pollutant in a short time, even at a low concentration stage, and as a result, a highly clean space can be easily secured. [Industrial applicability]

[0110] This collection adsorption column, collection method, and quantitative method allow for the rapid and highly sensitive collection and quantification of acidic or basic components in a gas. Furthermore, this management method, utilizing this collection adsorption column, collection method, and quantitative method, enables the rapid identification and removal of the contaminant source, even at low concentrations, thereby easily securing a highly clean environment. Therefore, this collection adsorption column, collection method, quantitative method, and management method can be used for managing spaces requiring a highly clean environment, such as in the manufacturing of electronic circuit boards. [Explanation of symbols]

[0111] 1. Acid component adsorption column 2. Basic component adsorption column 3. Suction pump 4 Connecting pipes

Claims

1. An adsorption column for collecting acidic or basic components in a gas, A non-porous substrate is filled in, The non-porous substrate holds a basic adsorbent for adsorbing acidic components or an acidic adsorbent for adsorbing basic components. The pressure loss when gas is drawn from the collection adsorption column at a suction rate of 2.0 L / min is 10 kPa or less. Adsorption column for collecting acidic or basic components in gases.

2. The adsorption column for collection according to claim 1, wherein the void volume of the adsorption column for collection is 200 μL or more and 3000 μL or less.

3. The adsorption column for collection according to claim 1, wherein the amount of the basic adsorbent or the acidic adsorbent is 0.4 μeq or more and 50 μeq or less.

4. A method for collecting acidic or basic components in a gas, comprising passing a gas through an adsorption column for collection described in any one of claims 1 to 3 to collect the acidic or basic components in the gas.

5. The collection method according to claim 4, wherein the gas is passed through the collection adsorption column at an airflow rate of 2.0 L / min or more.

6. A collection step of collecting acidic or basic components in the gas using the collection method described in claim 4, An elution step is to pass a solvent through the collection adsorption column on which the acid component or the base component has been collected, thereby eluting the collected acid component or the base component into the solvent to obtain an eluate, and A method for determining the concentration of an acidic component or a basic component in a gas, comprising a measurement step of measuring the concentration of the acidic component or the basic component in the eluent.

7. A quantitative step of quantifying the concentration of an acidic or basic component in a gas in a space using the quantitative method described in claim 6, and A method for controlling the cleanliness of a space, comprising the step of identifying and removing the source of the acidic or basic component in the gas inside the space when the concentration of the acidic or basic component quantified in the quantitative step exceeds a threshold.

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