Method for fractionating dioxins

Abstract

In a fractionation column (20) in which a first tube body (200) filled with a first layer (210) of a first agent containing hydrated activated magnesium silicate that is in powder form and that has been adjusted to have a water content of 1-4 mass% is coupled with a second tube body (300) filled with a second layer (310) of a second agent containing zirconia in powder form, a purification column (10) is coupled with an upper portion of the first tube body (200), a dioxin solution is added, and n-hexane is further supplied. A resultant n-hexane solution of dioxins passes through the first layer (210) in the first tube body (200) and the second layer (310) in the second tube body (300) in this order from the purification column (10). At such time, a dioxin group in the n-hexane solution is selectively captured in the first layer (210), and a polychlorinated biphenyl group in the n-hexane solution which has passed through the first layer (210) is captured in the second layer (310).

Description

Dioxin fractionation method

[0001] This application claims priority from Japanese Patent Application No. 2024-20686, filed on February 14, 2024, the contents of which are incorporated herein by reference. The present invention relates to a method for fractionating dioxins, and in particular to a method for fractionating dioxins contained in an aliphatic hydrocarbon solvent solution of dioxins.

[0002] Due to concerns about environmental pollution by highly toxic dioxins, countries are calling for the analysis and evaluation of dioxin contamination in exhaust gases from waste incineration plants, the atmosphere, water such as industrial wastewater and river water, fly ash generated at waste incineration plants, soil, etc. Similar analysis and evaluation is also often required for food.

[0003] Dioxins is a general term that refers to dioxins, such as polychlorinated dibenzoparadioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs). DL-PCBs are a group of 209 types of polychlorinated biphenyls (PCBs) that exhibit toxicity similar to that of PCDDs and PCDFs, and include non-ortho PCBs and mono-ortho PCBs.

[0004] When assessing dioxin contamination of environmental samples such as air or soil, or samples such as food samples, it is first necessary to extract dioxins from the sample to obtain a sample for analysis. When the sample is a solid material such as soil or solid food, dioxins are extracted from the solid material, for example, by the Soxhlet extraction method. When the sample is a fluid such as air or industrial wastewater, dioxins in the fluid are captured and collected using a collector such as a filter, and then the dioxins collected in the collector are extracted by cleaning the collector or applying the Soxhlet extraction method to the collector. The resulting extract is then purified and used as a sample for dioxin analysis.

[0005] Because this analytical sample contains all the extracted dioxins simultaneously, the results may be unreliable when quantitatively analyzed using an analytical instrument such as a gas chromatograph mass spectrometer (GC / MS). For example, it is known that mono-ortho-PCBs affect the quantitative analysis results of PCDDs and PCDFs, and conversely, PCDDs and PCDFs affect the quantitative analysis results of mono-ortho-PCBs.

[0006] Therefore, attempts have been made to fractionate the dioxins contained in the extract into several types, prepare multiple analytical samples, and analyze each analytical sample individually. For example, Patent Document 1 describes that by passing a solution of dioxins in an aliphatic hydrocarbon solvent through a treatment layer using an adsorbent containing activated magnesium silicate, it is possible to fractionate dioxins into a first group containing non-ortho PCBs, PCDDs, and PCDFs, and a second group containing mono-ortho PCBs and PCBs that do not fall under the category of DL-PCBs (non-DL-PCBs).

[0007] However, even if dioxins are fractionated in this manner, the accuracy of quantifying non-ortho PCBs may be impaired in analytical samples containing Group 1 when PCDDs are present at high concentrations. Furthermore, dioxins and PCBs may be required to be measured separately. For example, the U.S. Environmental Protection Agency (EPA) uses Method 1613B to measure PCDDs and PCDFs that may be present in matrices such as water, soil, and sediment, while Method 1668C measures all 209 PCBs that may be present in matrices such as wastewater. These methods require separate analysis of dioxins as PCDDs and PCDFs and PCBs.

[0008] Japanese Patent Application Laid-Open No. 2020-115111

[0009] The present invention is intended to separate dioxins into the dioxin group of PCDDs and PCDFs and the polychlorinated biphenyl group of DL-PCBs and other PCBs.

[0010] The present invention relates to a method for fractionating dioxins, which comprises a step of passing a solution of dioxins in an aliphatic hydrocarbon solvent through a first layer of a first agent containing hydrous magnesium silicate, the hydrous magnesium silicate used here having a water content of 1 to 4 mass %.

[0011] In the fractionation method of the present invention, when the aliphatic hydrocarbon solvent solution of dioxins passes through the first layer, the dioxin group of dioxins, i.e., PCDDs and PCDFs, is adsorbed and captured by the first agent. On the other hand, the polychlorinated biphenyl group of dioxins, i.e., DL-PCBs and other PCBs, remains in the aliphatic hydrocarbon solvent solution and passes through the first layer. As a result, the dioxins in the aliphatic hydrocarbon solvent solution are fractionated into the dioxins captured by the first layer and the polychlorinated biphenyls remaining in the aliphatic hydrocarbon solvent solution.

[0012] One form of the first agent used in the fractionation method of the present invention further comprises a carbon material mixed with the hydrous magnesium silicate.

[0013] The hydrous magnesium silicate used in the fractionation method of the present invention is prepared, for example, by adding water to activated magnesium silicate prepared by heat-treating magnesium silicate.

[0014] The fractionation method of the present invention typically further comprises the step of supplying a first polar solvent to the first layer through which the aliphatic hydrocarbon solvent solution has passed, and retaining the first polar solvent that has passed through the first layer.

[0015] In one embodiment of the fractionation method of the present invention, the aliphatic hydrocarbon solvent solution that has passed through the first layer is further passed through a second layer containing a second agent that includes at least one of an alumina-based material and a zirconia-based material.

[0016] In the fractionation method of the present invention according to this aspect, when the aliphatic hydrocarbon solvent solution that has passed through the first layer passes through the second layer, the polychlorinated biphenyls remaining in the aliphatic hydrocarbon solvent solution are adsorbed and captured by the second agent, and as a result, the dioxins in the aliphatic hydrocarbon solvent solution are fractionated into dioxins captured in the first layer and polychlorinated biphenyls captured in the second layer.

[0017] The fractionation method of the present invention according to this aspect typically further includes the step of separately supplying a first polar solvent and a second polar solvent to the first layer and the second layer through which the aliphatic hydrocarbon solvent solution has passed, respectively, and retaining the first polar solvent that has passed through the first layer and the second polar solvent that has passed through the second layer, respectively.

[0018] Another aspect of the present invention relates to a method for preparing a sample for analyzing dioxins contained in an aliphatic hydrocarbon solvent solution of dioxins. This preparation method includes the steps of passing the aliphatic hydrocarbon solvent solution through a first layer containing a first agent containing hydrous magnesium silicate, passing the aliphatic hydrocarbon solvent solution that has passed through the first layer through a second layer containing a second agent containing at least one of an alumina-based material and a zirconia-based material, supplying a first polar solvent to the first layer through which the aliphatic hydrocarbon solvent solution has passed and reserving the first polar solvent that has passed through the first layer as a first analytical sample, and supplying a second polar solvent to the second layer through which the aliphatic hydrocarbon solvent solution has passed and reserving the second polar solvent that has passed through the second layer as a second analytical sample. The hydrous magnesium silicate used here has a water content of 1 to 4% by mass.

[0019] In the preparation method of the present invention, when the aliphatic hydrocarbon solvent solution of dioxins passes through the first layer, the dioxin group of dioxins, i.e., PCDDs and PCDFs, is adsorbed and captured by the first agent. Meanwhile, the polychlorinated biphenyl group of dioxins, i.e., DL-PCBs and other PCBs, remains in the aliphatic hydrocarbon solvent solution and passes through the first layer. Then, when the aliphatic hydrocarbon solvent solution that has passed through the first layer passes through the second layer, the polychlorinated biphenyl group remaining in the aliphatic hydrocarbon solvent solution is adsorbed and captured by the second agent. As a result, the dioxins in the aliphatic hydrocarbon solvent solution are fractionated into the dioxins captured in the first layer and the polychlorinated biphenyls captured in the second layer. Therefore, the first analytical sample obtained by collecting the first polar solvent that has passed through the first layer can be used for analyzing the dioxin group of PCDDs and PCDFs among the dioxins contained in the aliphatic hydrocarbon solvent solution, and the second analytical sample obtained by collecting the second polar solvent that has passed through the second layer can be used for analyzing the polychlorinated biphenyl group of DL-PCBs and other PCBs among the dioxins contained in the aliphatic hydrocarbon solvent solution.

[0020] According to yet another aspect, the present invention relates to a method for analyzing dioxins contained in a solution of dioxins in an aliphatic hydrocarbon solvent, which comprises the step of separately analyzing, by gas chromatography or bioassay, a first analysis sample and a second analysis sample prepared by the method for preparing a sample for analyzing dioxins according to the present invention.

[0021] In this analytical method, the dioxin group of PCDDs and PCDFs among the dioxins contained in the aliphatic hydrocarbon solvent solution can be analyzed by analyzing the first analytical sample, and the polychlorinated biphenyl group of DL-PCBs and other PCBs among the dioxins contained in the aliphatic hydrocarbon solvent solution can be analyzed by analyzing the second analytical sample.

[0022] According to yet another aspect, the present invention relates to an apparatus for fractionating dioxins contained in a solution of dioxins in an aliphatic hydrocarbon solvent. The fractionation apparatus includes a first tubular body with both ends open and filled with a first layer made of a first agent containing hydrous magnesium silicate. The hydrous magnesium silicate used here has a water content of 1 to 4 mass %.

[0023] In one embodiment of the fractionation device according to the present invention, the first agent further comprises a carbon material mixed with the hydrous magnesium silicate.

[0024] The hydrous magnesium silicate used in the fractionation device according to the present invention is, for example, hydrous activated magnesium silicate.

[0025] Another embodiment of the fractionation device according to the present invention further includes a second tubular body having both open ends and filled with a second layer made of a second agent containing at least one of an alumina-based material and a zirconia-based material, and one end of the second tubular body is detachably connectable to one end of the first tubular body.

[0026] According to yet another aspect, the present invention relates to a fractionating agent for dioxins contained in an aliphatic hydrocarbon solvent solution, the fractionating agent comprising hydrous magnesium silicate, wherein the hydrous magnesium silicate used herein has a water content of 1 to 4 mass %.

[0027] One embodiment of the fractionation agent according to the present invention further comprises a carbonaceous material mixed with the hydrous magnesium silicate.

[0028] The hydrous magnesium silicate used in the fractionation agent of the present invention is, for example, hydrous activated magnesium silicate.

[0029] According to the method for fractionating dioxins of the present invention, dioxins contained in an aliphatic hydrocarbon solvent solution of dioxins can be fractionated into the dioxin group of PCDDs and PCDFs and the polychlorinated biphenyl group of DL-PCBs and other PCBs.

[0030] The method for preparing a sample for analyzing dioxins according to the present invention fractionates dioxins contained in an aliphatic hydrocarbon solvent solution of dioxins into dioxin group (PCDDs and PCDFs) and polychlorinated biphenyl group (DL-PCBs and other PCBs), thereby making it possible to individually prepare a first analytical sample for analyzing dioxin group (PCDDs and PCDFs) and a second analytical sample for analyzing polychlorinated biphenyl group (DL-PCBs and other PCBs).

[0031] The method for analyzing dioxins according to the present invention individually analyzes the first analysis sample and the second analysis sample prepared by the method for preparing a sample for analyzing dioxins according to the present invention, and therefore can improve the analytical accuracy of dioxins contained in an aliphatic hydrocarbon solvent solution, with respect to both the dioxin group of PCDDs and PCDFs and the polychlorinated biphenyl group of DL-PCBs and other PCBs.

[0032] The dioxin fractionation device according to the present invention can fractionate dioxins contained in an aliphatic hydrocarbon solvent solution of dioxins into dioxin groups such as PCDDs and PCDFs and polychlorinated biphenyl groups such as DL-PCBs and other PCBs.

[0033] The fractionation agent for dioxins according to the present invention can selectively adsorb and capture dioxin group PCDDs and PCDFs among dioxins contained in an aliphatic hydrocarbon solvent solution of dioxins, and separate them from polychlorinated biphenyl group DL-PCBs and other PCBs.

[0034] 1 is a schematic vertical cross-sectional view of a dioxin fractionator using one embodiment of the dioxin fractionation device according to the present invention.

[0035] The following describes a method for analyzing dioxins, while touching upon a method for fractionating dioxins and a method for preparing an analytical sample according to the present invention. This analytical method analyzes dioxins contained in a sample solution prepared by extracting dioxins from a target object in order to evaluate the level of contamination by dioxins.

[0036] The objects to be evaluated for dioxin contamination include, for example, environmental samples, food samples, and biological samples. Examples of environmental samples include material layers at the bottom of the hydrosphere or on the land surface, such as sediment and soil; environmental waters such as river water, lake water, and groundwater; wastewater such as industrial wastewater and domestic wastewater; electrical insulating oil; incineration ash produced in incineration facilities; and environmental air and exhaust gases emitted from incineration facilities. Examples of food samples include agricultural crops, meat, seafood, and processed foods thereof. Examples of biological samples include biological tissues, blood, and breast milk.

[0037] When the target substance is solid or liquid, the sample liquid can be prepared from the target substance by selecting an appropriate extraction method from various solid-liquid extraction methods or liquid-liquid extraction methods. When the target substance is gaseous, the target sample liquid can be prepared by collecting the gaseous components using a filter or the like and applying a solid-liquid extraction method to the filter or the like. When the food sample is an oily food such as fish oil, the food sample itself can also be used as the sample liquid.

[0038] The extraction solvent for preparing a sample solution from a target substance is not particularly limited as long as it can dissolve dioxins and polychlorinated biphenyls, and is typically an organic solvent. Examples of organic solvents that can be used include aliphatic hydrocarbon solvents, particularly nonpolar aliphatic hydrocarbon solvents having 5 to 10 carbon atoms such as n-hexane, isooctane, nonane, or decane; aromatic hydrocarbon solvents such as toluene or xylene; and polar organic solvents such as acetone, diethyl ether, or dichloromethane. It is preferable to use an extract obtained using an aromatic hydrocarbon solvent or a polar organic solvent as a sample solution by replacing the solvent with the aforementioned aliphatic hydrocarbon solvent.

[0039] Sample solutions typically contain various contaminants derived from the target substance along with dioxins. For example, sample solutions prepared from environmental samples typically contain polycyclic aromatic hydrocarbons such as halogenated diphenyl ethers (PCDEs) and paraffinic substances along with dioxins. PCDEs can affect the analysis results of PCDFs. Furthermore, paraffinic substances (especially hydrocarbons with 20 or more carbon atoms) present in large amounts in sample solutions can cause ionization suppression in GC / MS analysis, potentially affecting the analysis results of dioxins and polychlorinated biphenyls.

[0040] One embodiment of an analytical sample preparer used in carrying out the dioxin analysis method of the present invention will be described with reference to Figure 1. In the figure, preparer 1 is installed in an upright position and mainly comprises a purification column 10 and a fractionation column 20 (one embodiment of the dioxin fractionation device of the present invention) connected to purification column 10 so as to form a continuous flow path system. Note that Figure 1 shows an overview of each part of preparer 1 and does not accurately reflect the structure, shape, size, proportions, etc. of each part.

[0041] The purification column 10 is a cylindrical member with both ends open, and is made of a material that is at least solvent-resistant, chemical-resistant, and heat-resistant, such as glass, resin, or metal. The purification column 10 has a threaded portion (not shown) on the outer surface of the lower end for connecting to the fractionation column 20, and is filled with a purification layer 100 inside. The purification layer 100 is used to process some of the impurities contained in the sample solution, for example, to decompose the impurities or capture the impurities or their decomposition products. The purification layer 100 is a multi-layer silica gel layer formed by stacking a silver nitrate silica gel layer 110 and a sulfate silica gel layer 120 in this order downward within the purification column 10.

[0042] The silver nitrate silica gel layer 110 is a layer formed from silver nitrate silica gel. The silver nitrate silica gel used here is prepared by uniformly adding an aqueous solution of silver nitrate to the surface of granular silica gel (usually activated silica gel whose activity has been increased by heating) with a particle size of approximately 40 to 210 μm, followed by removing water by heating under reduced pressure. The amount of silver nitrate supported relative to the silica gel is usually preferably set to 5 to 20% by mass of the silica gel. If this amount is less than 5%, the effect of treating impurities in the silver nitrate silica gel layer 110 may be reduced. Conversely, if it exceeds 20%, the amount of silver ions in the silver nitrate silica gel layer 110 increases, making it easier for dioxins to be captured, and there is a possibility that some of the dioxins contained in the dioxin solution may be lost.

[0043] The water content of the silver nitrate silica gel layer 110 is generally preferably set to 2 to 10% by mass of silica gel, and more preferably 3.5 to 5%. If the water content is 2% or less, the activity of silver ions in the silver nitrate silica gel layer 110 increases, making it easier to capture dioxins, and there is a possibility that some of the dioxins contained in the dioxin solution will be lost. Conversely, if the water content exceeds 10%, there is a possibility that the effect of treating impurities in the silver nitrate silica gel layer 110 will be reduced.

[0044] The packing density of the silver nitrate silica gel in the silver nitrate silica gel layer 110 is not particularly limited as long as it can ensure liquid permeability, but is usually 0.3 to 0.8 g / cm ３ It is preferable to set it to 0.4 to 0.7 g / cm ３ It is more preferable to set the density to 0.3 g / cm ３ If the density is less than 0.8 g / cm3, the efficiency of treating impurities may decrease. ３ If the temperature exceeds this range, it becomes difficult for the aliphatic hydrocarbon solvent, which will be described later, to pass through the purification layer 100 .

[0045] The sulfated silica gel layer 120 is a layer formed from sulfated silica gel. The sulfated silica gel used here is prepared by uniformly adding concentrated sulfuric acid to the surface of granular silica gel (usually activated silica gel whose activity has been increased by heating) with a particle size of approximately 40 to 210 μm. The amount of concentrated sulfuric acid added to the silica gel is usually preferably set to 10 to 60% of the mass of the silica gel.

[0046] The packing density of the sulfate silica gel in the sulfate silica gel layer 120 is not particularly limited as long as it can ensure liquid permeability, but is usually 0.3 to 1.1 g / cm ３ It is preferable to set it to 0.5 to 1.0 g / cm ３ It is more preferable to set the density to 0.3 g / cm ３ If the density is less than 1.1 g / cm3, the efficiency of treating impurities may decrease. ３ If the temperature exceeds this range, it becomes difficult for the aliphatic hydrocarbon solvent, which will be described later, to pass through the purification layer 100 .

[0047] In the purification layer 100, the ratio of the silver nitrate silica gel layer 110 to the sulfate silica gel layer 120 is preferably set to 1.0 to 50 times, more preferably 3.0 to 30 times, by mass, of the sulfate silica gel layer 120 to the silver nitrate silica gel layer 110. When the mass ratio of the sulfate silica gel layer 120 exceeds 50 times, the proportion of the silver nitrate silica gel layer 110 becomes relatively small, and the purification layer 100 may be unable to process impurities contained in the sample solution, particularly its ability to adsorb impurities. Conversely, when the mass ratio of the sulfate silica gel layer 120 is less than 1.0 times, the purification layer 100 may be unable to process impurities contained in the sample solution, particularly its ability to decompose impurities.

[0048] The purification layer 100 may have an activated silica gel layer disposed between the silver nitrate silica gel layer 110 and the sulfuric acid silica gel layer 120. This activated silica gel layer is intended to prevent the silver nitrate silica gel layer 110 and the sulfuric acid silica gel layer 120 from chemically reacting with each other due to direct contact between them. The purification layer 100 may also have an activated silica gel layer disposed below the sulfuric acid silica gel layer 120. This activated silica gel layer is intended to adsorb decomposition products generated when impurities in the sample solution are treated in the silver nitrate silica gel layer 110 and the sulfuric acid silica gel layer 120, as well as sulfuric acid eluted from the sulfuric acid silica gel layer 120, and to prevent these from migrating to the fractionation column 20.

[0049] Fractionation column 20 is essentially a cylindrical member with both ends open, made of the same material as purification column 10, and is divided into an upper first tubular body 200 and a lower second tubular body 300. First tubular body 200 has a first mounting section 21 formed at its upper end, into which the lower end portion of purification column 10 can be inserted. The inner circumferential surface of first mounting section 21 is formed with a threaded portion (not shown) that corresponds to the threaded portion of the lower end portion of purification column 10. Furthermore, first tubular body 200 has a first branch channel 22 with an open tip below first mounting section 21, and a threaded portion (not shown) on the outer circumferential surface of the lower end portion of the figure for connecting to second tubular body 300.

[0050] The second pipe 300 has a second attachment section 31 formed at its upper end, into which the lower end portion of the first pipe 200 can be inserted. A threaded section (not shown) corresponding to the threaded section at the lower end of the first pipe 200 is formed on the inner circumferential surface of the second attachment section 31. The second pipe 300 also has a second branch passage 32 below the second attachment section 31, the tip of which is open.

[0051] The inside of the first tubular body 200 is filled with a first layer 210 below the first branched passage 22. The first layer 210 is for selectively adsorbing dioxin groups (PCDDs and PCDFs) among dioxins, and is made of a first agent containing hydrous magnesium silicate. The hydrous magnesium silicate contained in the first agent is obtained by adding water to magnesium silicate to give it moisture. Magnesium silicate is a silicate in which electronegative atomic groups containing oxygen and magnesium are coordinated around a silicon atom at the center, and is generally represented by xMgO.ySiO ２ Magnesium silicate exists in a variety of compositions with different combinations of x and y, and can be expressed as a hydrate (in this case, xMgO.ySiO ２ ・nH ２ It may be represented by the chemical formula: 0. Typical examples of the combination of x and y (x:y) in sodium silicate include 2:5, 2:3, and 3:4. Of these, it is preferable to use one in which the ratio of x:y is 2:3.

[0052] The magnesium silicate used in the first agent is preferably in a porous granular or powder form, for example, having a particle size of 38 to 250 μm (60 to 390 mesh), particularly 75 to 150 μm (100 to 200 mesh), which is capable of ensuring liquid permeability in the first layer 210. Granular or powdered magnesium silicate is commercially available from several companies under the trade name "Florisil," for example, and these commercially available products can be used.

[0053] Furthermore, the magnesium silicate used in the first agent is preferably activated magnesium silicate, which is obtained by heat-treating magnesium silicate to remove moisture and thereby enhance its adsorption capacity. The use of activated magnesium silicate makes it easier to control the moisture content of the target hydrous magnesium silicate. Furthermore, it is possible to remove organic matter that may be mixed into the magnesium silicate, and the selective adsorption capacity of the first agent for dioxins can be further stabilized.

[0054] Heat treatment to activate magnesium silicate is typically performed using a constant-temperature dryer at approximately 130°C for approximately 24 hours. Alternatively, heat treatment can be performed using a tubular furnace under a stream of inert gas such as nitrogen. In this case, the heat treatment time can be shortened and magnesium silicate can be activated efficiently. In this case, the heating temperature is preferably set to 650°C or less, and more preferably set to 550°C or less. Magnesium silicate heated at temperatures above 650°C may be altered beyond the activation level due to moisture removal and lose its desired functionality. The lower limit of the heating temperature is not particularly limited, but is typically preferably set to 100°C or higher, and more preferably set to 450°C or higher. The flow rate of the inert gas is preferably set to 0.5 to 1.0 L / min. The heating time may vary depending on the heating temperature, but is typically preferably set to 0.5 to 3 hours, and more preferably set to 1 to 2 hours.

[0055] Hydrous magnesium silicate is prepared by adding water to magnesium silicate or activated magnesium silicate to adjust the water content to 1 to 4% by mass. The added water is purified water such as distilled water, ion-exchanged water, or pure water. If the water content of the hydrous magnesium silicate is less than 1% by mass, the adsorption power of the first agent becomes too strong, and some of the polychlorinated biphenyls tend to be easily adsorbed along with the dioxins in the first layer 210. Conversely, if the water content exceeds 4% by mass, the adsorption power of the first agent becomes weak, and some of the dioxins tend to be less easily adsorbed in the first layer 210. Note that when the magnesium silicate is a hydrate, the water content of the hydrous magnesium silicate includes that due to water of hydration.

[0056] The first agent may further contain a carbon material mixed with hydrous magnesium silicate in order to finely adjust and enhance the selective adsorption power of dioxins in the first layer 210. The carbon material is in the form of granules or powder with a particle size of about 1 to 300 μm and a specific surface area of ​​10 to 2,500 m as measured by the BET method. ２Porous materials with a pore size of 1 / g and adsorbent properties can be used, for example, graphite, activated carbon materials such as coconut shell charcoal (i.e., unactivated activated carbon materials), or activated carbon, in order of decreasing adsorption power. The carbon material is preferably one that has been heat-treated or washed with an organic solvent to remove organic compounds remaining as impurities. Two or more types of carbon materials may also be used in combination.

[0057] The amount of carbonaceous material mixed with hydrous magnesium silicate may vary depending on the type of carbonaceous material, but since increasing the amount makes it easier for the first agent to adsorb not only dioxins but also some of the polychlorinated biphenyls, it is preferable to control the amount to a small amount depending on the adsorption power of the carbonaceous material used. For example, it is preferable to set the amount to about 0.01 to 2 mass % for graphite, about 0.1 to 0.5 mass % for activated carbon material, and about 0.01 to 0.04 mass % for activated carbon.

[0058] The first agent containing a carbonaceous material together with hydrous magnesium silicate can also be prepared by heating a mixture of magnesium silicate and the carbonaceous material to activate the magnesium silicate, and then adding water to the mixture. The heat treatment method in this case is the same as the heat treatment method for activating magnesium silicate described above.

[0059] The filling density of the first agent in the first layer 210 is not particularly limited as long as it is within a range that ensures liquid permeability, but is usually 0.2 to 1.5 g / cm ３ It is preferable to set it to 0.3 to 0.8 g / cm ３ It is more preferable to set it to .

[0060] The inside of the second pipe 300 is filled with a second layer 310 below the second branch passage 32. The second layer 310 is made of a second agent made of an alumina-based material or a zirconia-based material. The alumina-based material used as the second agent has a specific surface area of ​​10 to 500 m ２The second agent is a porous aluminum oxide having an adsorption property and a particle size of about 40 to 300 μm, and is usually either basic alumina, neutral alumina, or acidic alumina. The zirconia-based material used as the second agent has a specific surface area of ​​10 to 500 m. ２ The alumina-based material and the zirconia-based material may be mixed and used.

[0061] The filling density of the second agent in the second layer 310 is not particularly limited as long as it is within a range that ensures liquid permeability, but is usually 0.5 to 1.2 g / cm ３ It is preferable to set it to 0.6 to 1.1 g / cm ３ It is more preferable to set it to .

[0062] The fractionation column 20 is integrated by screwing the lower end of the first tubular body 200 to the second attachment portion 31 of the second tubular body 300 to provide a liquid-tight and detachable connection, and in this state, the first tubular body 200 and the second tubular body 300 form a continuous flow path. Furthermore, the fractionation column 20, in which the first tubular body 200 and the second tubular body 300 are integrated, is liquid-tightly and detachably connected to the purification column 10 by screwing the lower end of the purification column 10 to the first attachment portion 21.

[0063] The size of the preparer 1 can be appropriately set depending on the amount of sample liquid to be treated. For example, when the amount of sample liquid is about 1 to 20 mL, it is preferable that the inner diameter of the portion of the purification column 10 that can be packed with the purification layer 100 is 13 to 16 mm and the length is about 180 to 190 mm, and that the inner diameters of the first tubular body 200 and the second tubular body 300 that can be packed with the first layer 210 are both 5 to 7 mm, and that the length of the portion of the first tubular body 200 that can be packed with the first layer 210 is about 31 to 33 mm, and that the length of the portion of the second tubular body 300 that can be packed with the second layer 310 is about 29 to 31 mm.

[0064] Next, a method for preparing a dioxin analysis sample from a sample solution using the preparer 1 will be described. In preparing the analysis sample, the preparer 1 is placed upright as shown in Figure 1, and the sample solution is added onto the purification layer 100 in the purification column 10 through the opening at the top. At this time, it is preferable to heat part of the purification layer 100, i.e., the entire silver nitrate silica gel layer 110 and the upper part of the sulfate silica gel layer 120.

[0065] The added sample liquid permeates the upper part of the silver nitrate silica gel layer 110 and is heated together with a portion of the purification layer 100. The heating temperature of the purification layer 100 is set to 35°C or higher, preferably 50°C or higher, and more preferably 60°C or higher. This heating causes some of the impurities other than dioxins contained in the sample liquid to react with the purification layer 100 and be decomposed. If the heating temperature is lower than 35°C, the reaction between the impurities and the purification layer 100 will be slower, and some of the impurities may be more likely to remain in the analytical sample. There is no particular upper limit to the heating temperature, but from a safety standpoint, it is usually preferable that the temperature be equal to or lower than the boiling point of the sample liquid.

[0066] Next, after a predetermined time, e.g., 10 to 60 minutes, has elapsed since the start of heating, an aliphatic hydrocarbon solvent is supplied to and passed through the purification layer 100 in the purification column 10 through the opening at the top. At this time, the purification layer 100 is typically cooled to room temperature after heating is stopped, or the heating is maintained so that the temperature is between 35°C and 60°C. If the purification layer 100 is heated to a high temperature of 60°C or higher when the aliphatic hydrocarbon solvent is supplied, some of the polychlorinated biphenyls contained in the added sample solution may decompose. The aliphatic hydrocarbon solvent supplied here is capable of dissolving dioxins and polychlorinated biphenyls, and is preferably an aliphatic saturated hydrocarbon solvent having 5 to 8 carbon atoms. For example, n-pentane, n-hexane, n-heptane, n-octane, isooctane, or cyclohexane is preferably used. These solvents may also be used in combination.

[0067] The aliphatic hydrocarbon solvent supplied to purification layer 100 dissolves dioxins and polychlorinated biphenyls contained in the sample solution that has permeated purification layer 100, as well as decomposition products of the impurities and remaining undecomposed impurities, and passes through purification layer 100 as an aliphatic hydrocarbon solvent solution. During this process, some of the decomposition products and impurities are adsorbed onto silver nitrate silica gel layer 110 and sulfuric acid silica gel layer 120, but the paraffinic substances and PCDEs, which are impurities, pass through purification layer 100 together with the aliphatic hydrocarbon solvent. The aliphatic hydrocarbon solvent solution passing through purification layer 100 is naturally cooled as it passes through the non-heated portion, i.e., the lower part of sulfuric acid silica gel layer 120.

[0068] The aliphatic hydrocarbon solvent solution that has passed through the purification layer 100 flows from the purification column 10 to the fractionation column 20, and passes through the first layer 200 of the first tubular body 200. At this time, dioxins contained in the aliphatic hydrocarbon solvent solution from the purification layer 100 are adsorbed and captured by the first agent 210, and are separated from the aliphatic hydrocarbon solvent solution. On the other hand, polychlorinated biphenyls and impurities such as paraffinic substances and PCDEs contained in the aliphatic hydrocarbon solvent solution from the purification layer 100 remain in the aliphatic hydrocarbon solvent solution and pass through the first layer 210, and the aliphatic hydrocarbon solvent solution flows from the first tubular body 200 to the second tubular body 300.

[0069] The aliphatic hydrocarbon solvent solution that has flowed into the second tubular body 300 passes through the second layer 310, flows out from the opening at the lower end of the second tubular body 300, and is discarded. At this time, the polychlorinated biphenyls and PCDEs contained in the aliphatic hydrocarbon solvent solution are adsorbed and captured by the second layer 310 and separated from the aliphatic hydrocarbon solvent solution. Meanwhile, the paraffin-based substances contained in the aliphatic hydrocarbon solvent solution remain in the aliphatic hydrocarbon solvent solution, pass through the second layer 310, and are discarded. As a result, the polychlorinated biphenyls captured in the second layer 310 are separated from the paraffin-based substances.

[0070] Through the above process, the dioxins contained in the sample solution are fractionated into a dioxin-group fraction of PCDDs and PCDFs captured in the first layer 210 in the fractionation column 20, and a polychlorinated biphenyl-group fraction of DL-PCBs and other PCBs captured in the second layer 310. Each fraction can be extracted by the following procedure.

[0071] After the aliphatic hydrocarbon solvent solution has passed through the second layer 310, the opening at the upper end of the purification column 10 and the opening of the first branch passage 22 of the first tubular body 200 are hermetically closed, and the first extraction solvent is supplied from the opening at the lower end of the second tubular body 300 and passed through the second layer 310.

[0072] The extraction solvent used here is preferably a polar solvent (i.e., a second polar solvent) suitable for gas chromatography, a common method for analyzing dioxins, such as toluene or benzene. Alternatively, a mixed solvent in which an aliphatic hydrocarbon solvent or an organic chlorine-based solvent is added to toluene or benzene can also be used as the polar solvent. Examples of the aliphatic hydrocarbon solvent used in the mixed solvent include n-pentane, n-hexane, n-heptane, n-octane, isooctane, and cyclohexane. Examples of the organic chlorine-based solvent include dichloromethane, trichloromethane, and tetrachloromethane. If necessary, a bioassay method can also be used as the analysis method for dioxins. In this case, a hydrophilic polar solvent such as dimethyl sulfoxide (DMSO) or methanol is used as the extraction solvent.

[0073] The extraction solvent supplied to the second layer 310 extracts the polychlorinated biphenyls captured in the second layer 310, flows to the second branched channel 32 of the second pipe 300, and is discharged from the second branched channel 32. By securing the extraction solvent discharged from the second branched channel 32 in this manner, i.e., the extraction solvent that has passed through the second layer 310, an extract of polychlorinated biphenyls, i.e., a sample for analysis of polychlorinated biphenyls of DL-PCBs and other PCBs (i.e., a second analysis sample), is obtained.

[0074] Next, the opening at the top end of the purification column 10 and the opening at the second branch path 32 of the second tubular body 300 are airtightly closed, and a polar solvent (i.e., a first polar solvent) is supplied as an extraction solvent from the opening at the bottom end of the second tubular body 300 and passed through the second layer 310 and the first layer 210 in that order. The polar solvent used here is similar in its selection to the second polar solvent. The first polar solvent may be the same as or different from the second polar solvent.

[0075] The extraction solvent supplied to the first layer 210 through the second layer 310 extracts the dioxins captured in the first layer 210, flows to the first branched channel 22 of the first pipe 200, and is discharged from the first branched channel 22. By securing the extraction solvent discharged from the first branched channel 22 in this manner, i.e., the extraction solvent that has passed through the first layer 210, an extract of the dioxins captured in the first layer 210, i.e., a sample for analysis of the dioxins of PCDDs and PCDFs (i.e., a first analytical sample), is obtained.

[0076] As described above, a sample for analysis of dioxins (first sample for analysis) and a sample for analysis of polychlorinated biphenyls (second sample for analysis) can be separately prepared from a sample solution using preparer 1. Furthermore, the first sample for analysis is reduced in contamination with PCDEs, which may affect the quantification of some dioxins, and the second sample for analysis is reduced in contamination with paraffinic substances, which may affect the quantification of some polychlorinated biphenyls.

[0077] The first analytical sample and the second analytical sample can be analyzed by gas chromatography, preferably gas chromatography using a high-resolution GC / MS, or by bioassay. Here, analysis of the first analytical sample allows for highly accurate analysis of individual PCDDs and PCDFs of the dioxin group contained in the sample solution, and analysis of the second analytical sample allows for highly accurate analysis of individual DL-PCBs and other PCBs of the polychlorinated biphenyl group contained in the sample solution.

[0078] The preparer 1 according to the above-described embodiment can be modified in various ways. For example, the order of the silver nitrate silica gel layer 110 and the sulfuric acid silica gel layer 120 in the purification layer 100 of the purification column 10 may be reversed. In this case, impurities contained in the sample solution are decomposed mainly in the sulfuric acid silica gel layer 120, and the decomposition products and some of the impurities are captured mainly in the silver nitrate silica gel layer 110.

[0079] Furthermore, the fractionation column 20 may not have the first branch path 22 and the second branch path 32. When such a fractionation column 20 is used, the dioxins and polychlorinated biphenyls captured in the first layer 210 and the second layer 310 of the fractionation column 20, respectively, can be extracted by removing the fractionation column 20 from the purification column 10, dividing the fractionation column 20 into the first tubular body 200 and the second tubular body 300, and supplying the extraction solvent to the first tubular body 200 and the second tubular body 300, respectively.

[0080] The present invention can contribute to improving living environments through the analysis of dioxins and polychlorinated biphenyls, which are known as environmental pollutants, and can therefore contribute to the realization of Goal 3 of the United Nations-led Sustainable Development Goals (SDGs), which aims to "ensure good health and promote well-being for all."

[0081] Examples will be given below, but the present invention is not limited to these examples.

[0082] The sample solutions used in the following examples are as follows. Mock sample: Mock samples were prepared by adding 0.02 mL of a diluted solution prepared by adding 100 mL of decane to 1 mL of a dioxin group standard substance (trade name "Mass-Labelled PCDD / PCDF Solution / Mixture DF-LCS-A" by Wellington Laboratories) and 0.02 mL of a diluted solution prepared by adding 100 mL of decane to 1 mL of a polychlorinated biphenyl group standard substance (trade name "Native PCB Solution / Mixture for MS Detection BP-MS" by Wellington Laboratories) to 5 mL of n-hexane. The dioxin group standard substances used here were１３ C １２ The polychlorinated biphenyl standard substance used here contains 62 polychlorinated biphenyl congeners / isomers identified by IUPAC numbers in Table 1 and elsewhere, and the individual concentrations are known. Of the 62 polychlorinated biphenyl congeners / isomers, non-ortho PCBs #77, #81, #126, and #169 and mono-ortho PCBs #105, #114, #118, #123, #156, #157, #167, and #189 are DL-PCBs, while the others are non-DL-PCBs. Six types, #28, #52, #101, #138, #153, ​​and #180, are non-DL-PCBs but are subject to EU food regulations.

[0083] Environmental sample: 10 g of soil collected from a factory site was subjected to the Soxhlet extraction method using toluene as the extraction solvent to obtain a toluene extract. The toluene was removed from the toluene extract, and the residue was dissolved in n-hexane to prepare 5 mL of a hexane solution. To this hexane solution, 0.02 mL of a dilution solution prepared by adding 1 mL of decane to 100 mL of a dioxin group standard substance (Wellington Laboratories' product name "Mass-Labelled PCDD / PCDF Solution / Mixture DF-LCS-A") and 0.02 mL of a dilution solution prepared by adding 1 mL of decane to 1 mL of a polychlorinated biphenyl group standard substance (Wellington Laboratories' product name "Mass-Labelled PCB Extraction Standard PCB-LCS-H") were added to prepare environmental samples. The polychlorinated biphenyl group standard substances used here were: １３ C １２ The study included 35 polychlorinated biphenyl congeners / isomers labeled with chlorine-containing ...

[0084] Comparative Example 1 An analytical sample was prepared from a sample solution using a preparer 1 having the configuration shown in Figure 1. The specifications of each part of the preparer 1 are as follows: Purification column 10 In a purification column 10 having an outer diameter of 18 mm, an inner diameter of 16 mm, and a length of 220 mm, a purification layer 100 was formed by layering 2.5 g of silver nitrate silica gel (packing height 30 mm) on 8 g of sulfate silica gel (packing height 70 mm). The sulfate silica gel and silver nitrate silica gel used here are as follows:

[0085] Sulfuric acid silica gel: Sulfuric acid silica gel was prepared by uniformly adding concentrated sulfuric acid (product name "Concentrated Sulfuric Acid" 190-04675, for precision analysis, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) to activated silica gel (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) and then drying. The amount of concentrated sulfuric acid added to the activated silica gel was set so that the amount of sulfuric acid relative to the activated silica gel was 44% by mass.

[0086] Silver nitrate silica gel: An aqueous solution of silver nitrate (product name "Silver Nitrate" 198-00835, special grade reagent, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) dissolved in distilled water was added to activated silica gel (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and mixed uniformly. This mixture was heated to 70°C under reduced pressure using a rotary evaporator and dried to prepare silver nitrate silica gel. Here, the silver nitrate aqueous solution used had a silver nitrate content of 10% relative to the mass of the activated silica gel, and the silver nitrate content in the silver nitrate silica gel was set to 10% based on the mass of the activated silica gel.

[0087] Fractionation column 20, first tubular body 200: The first tubular body 200 had an outer diameter of 8 mm, an inner diameter of 6 mm, and a length of 60 mm. 0.4 g of the first agent was packed to a height of 30 mm to form the first layer 210. The first agent used here was activated magnesium silicate obtained by heating magnesium silicate (trade name "Florisil, 75-150 μm" by Fujifilm Wako Pure Chemical Industries, Ltd.) in a tubular furnace at 500°C for 2 hours under a nitrogen gas flow at a flow rate of 0.5 L / min to remove organic matter and moisture.

[0088] Second tubular body 300: The second tubular body 300 had an outer diameter of 8 mm, an inner diameter of 6 mm, and a length of 60 mm. 0.75 g of the second agent was filled to a height of 30 mm to form the second layer 310. The second agent used here was powdered zirconia (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.).

[0089] In the analytical sample preparation operation, approximately 5 mL of the simulant sample was added to the silver nitrate silica gel layer 110 of the purification layer 100. The purification layer 100 was then heated at 60°C for 10 minutes and then cooled to 40°C. Then, while the purification layer 100 was maintained at 40°C, 85 mL of n-hexane was gradually supplied to the purification layer 100, and this n-hexane was passed through the purification layer 100, first layer 210, and second layer 310, in that order. After the n-hexane passed through the second layer 310, compressed air was passed through the first layer 210 and second layer 310 to dry both layers. Then, 1.2 mL of toluene was supplied to the second layer 310 from the opening at the lower end of the second tubular body 300, and the toluene that passed through the second layer 310 was collected through the second branch path 32, thereby obtaining a second analytical sample. Next, 1.5 mL of toluene was supplied from the opening side of the lower end of the second tubular body 300 through the second layer 310 to the first layer 210, and the toluene that passed through the first layer 210 was collected through the first branch path 22, thereby obtaining a first analytical sample. The time required from the addition of the simulation sample to the preparation of the first analytical sample was approximately 90 minutes.

[0090] The first and second analytical samples were each quantitatively analyzed by HRGC / HRMS, and the recovery rates of dioxins and polychlorinated biphenyls contained in the simulated samples were calculated. For this analysis, 0.02 mL of a dilution solution prepared by adding 1 mL of a dioxin internal standard (Wellington Laboratories' product name "Mass-Labelled PCDD syringe spike solution DF-IS-J") to 100 mL of decane was added to each analytical sample. Also, 0.02 mL of a dilution solution prepared by adding 1 mL of a polychlorinated biphenyl internal standard (Wellington Laboratories' product name "Mass-Labelled PCB Extraction Standard PCB-LCS-H") to 100 mL of decane was added to each analytical sample. The recovery rate refers to the ratio (%) of the dioxins or polychlorinated biphenyls contained in the respective analytical samples (i.e., the dioxins or polychlorinated biphenyls recovered in each analytical sample) to the dioxins or polychlorinated biphenyls contained in the sample solution added to the purification layer 100. The results are shown in Table 1.

[0091] Examples 1 and 2 Distilled water was added to the activated magnesium silicate used as the first agent in Comparative Example 1 to prepare hydrous activated magnesium silicate with a water content adjusted to 1% by mass (Example 1) or 3% by mass (Example 2). A first analytical sample and a second analytical sample were prepared from the simulated sample in the same manner as in Comparative Example 1, except that this hydrous activated magnesium silicate was used as the first agent. Each analytical sample was quantitatively analyzed in the same manner as in Comparative Example 1, and the recovery rates of dioxins and polychlorinated biphenyls were calculated. The results are shown in Table 1.

[0092] Comparative Example 2 Distilled water was added to the activated magnesium silicate used as the first agent in Comparative Example 1 to prepare hydrous activated magnesium silicate with a water content adjusted to 5% by mass. A first analytical sample and a second analytical sample were prepared from the simulated sample in the same manner as in Comparative Example 1, except that this hydrous activated magnesium silicate was used as the first agent. Each analytical sample was quantitatively analyzed in the same manner as in Comparative Example 1, and the recovery rates of dioxins and polychlorinated biphenyls were calculated. The results are shown in Table 1.

[0093]

[0094]

[0095]

[0096] Examples 3 to 7: A mixture of magnesium silicate (trade name "Florisil, 75 to 150 μm" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and powdered coconut shell charcoal (trade name "CHD" manufactured by Futamura Chemical Co., Ltd.; specific surface area 345 m) was used. ２ / g) was added in the proportions shown in Table 2 and mixed uniformly. This mixture was heated in a tubular furnace at 500°C for 2 hours under a nitrogen stream with a flow rate of 0.5 L / min to prepare a mixture containing activated magnesium silicate and coconut shell charcoal, from which organic matter and moisture had been removed. Distilled water was added to this mixture to obtain a mixture containing hydrous activated magnesium silicate and coconut shell charcoal, with the moisture content adjusted as shown in Table 2. A first analytical sample and a second analytical sample were prepared from the simulated sample in the same manner as in Comparative Example 1, except that this mixture was used as the first agent. Each analytical sample was quantitatively analyzed in the same manner as in Comparative Example 1, and the recovery rates of dioxins and polychlorinated biphenyls were calculated. The results are shown in Table 3.

[0097]

[0098]

[0099]

[0100]

[0101]

[0102] Examples 8 to 11: First and second analytical samples were prepared from the environmental samples in the same manner as in Examples 3, 4, 5, and 7, except that the simulated samples were replaced with environmental samples. Each analytical sample was quantitatively analyzed in the same manner as in Comparative Example 1, except that the internal standard substance for the polychlorinated biphenyl group added to each analytical sample was changed to 0.02 mL of a dilution solution prepared by adding 100 mL of decane to 1 mL of "Mass-Labelled PCB Internal / Recovery Standards PCB-ISS-H" (a product name of Wellington Laboratories). The recovery rates of the dioxins and polychlorinated biphenyls were calculated, and the results are shown in Table 4.

[0103]

[0104]

[0105] Reference Example 1: Instead of the activated magnesium silicate used as the first agent in Comparative Example 1, silica gel (trade name "Wakosil 60, 64 μm to 210 μm" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and activated carbon (trade name "Taiko S" manufactured by Futamura Chemical Co., Ltd.) were mixed to prepare activated carbon-dispersed silica gel with an activated carbon content of 0.8% by mass. This activated carbon-dispersed silica gel corresponds to the activated carbon-dispersed silica gel used for fractionating dioxins as specified in Japanese Industrial Standards JIS K 0311:2020 and the like. A first analytical sample and a second analytical sample were prepared from the simulated sample using the same procedure as in Comparative Example 1, except that the prepared activated carbon-dispersed silica gel was used as the first agent. Each analytical sample was quantitatively analyzed in the same manner as in Comparative Example 1, and the recovery rates of dioxins and polychlorinated biphenyls were calculated. The results are shown in Table 5.

[0106] Reference Example 2 A first analytical sample and a second analytical sample were prepared from the simulated sample in the same manner as in Reference Example 1, except that powdered alumina (Merck trade name "Aluminum Oxide 90, activated, basic, activity level I") was used instead of the powdered zirconia used as the second agent in Reference Example 1. Each analytical sample and the n-hexane waste liquid that had passed through the second layer were quantitatively analyzed in the same manner as in Comparative Example 1, and the recovery rates of dioxins and polychlorinated biphenyls were calculated. The results are shown in Table 5.

[0107]

[0108]

[0109]

[0110] 20 fractionation column 200 first tubular body 210 first layer 300 second tubular body 310 second layer

Claims

1. A method for fractionating dioxins, comprising the step of passing a solution of dioxins in an aliphatic hydrocarbon solvent through a first layer of a first agent containing hydrous magnesium silicate, wherein the water content of the hydrous magnesium silicate is 1 to 4 mass%.

2. The method for fractionating dioxins according to claim 1, wherein the first agent further comprises a carbon material mixed with the hydrous magnesium silicate.

3. The method for fractionating dioxins according to claim 1, wherein the hydrous magnesium silicate is prepared by adding water to activated magnesium silicate which has been prepared by heat-treating magnesium silicate.

4. A method for fractionating dioxins according to any one of claims 1 to 3, further comprising the step of supplying a first polar solvent to the first layer through which the aliphatic hydrocarbon solvent solution has passed, and retaining the first polar solvent that has passed through the first layer.

5. A method for fractionating dioxins according to any one of claims 1 to 3, wherein the aliphatic hydrocarbon solvent solution that has passed through the first layer is further passed through a second layer containing a second agent containing at least one of an alumina-based material and a zirconia-based material.

6. The method for fractionating dioxins according to claim 5, further comprising the steps of separately supplying a first polar solvent and a second polar solvent to the first layer and the second layer through which the aliphatic hydrocarbon solvent solution has passed, respectively, and retaining the first polar solvent that has passed through the first layer and the second polar solvent that has passed through the second layer, respectively.

7. A method for preparing a sample for analyzing dioxins contained in an aliphatic hydrocarbon solvent solution of dioxins, comprising the steps of: passing the aliphatic hydrocarbon solvent solution through a first layer made of a first agent containing hydrous magnesium silicate; passing the aliphatic hydrocarbon solvent solution that has passed through the first layer through a second layer made of a second agent containing at least one of an alumina-based material and a zirconia-based material; supplying a first polar solvent to the first layer through which the aliphatic hydrocarbon solvent solution has passed, and securing the first polar solvent that has passed through the first layer as a first analytical sample; and supplying a second polar solvent to the second layer through which the aliphatic hydrocarbon solvent solution has passed, and securing the second polar solvent that has passed through the second layer as a second analytical sample, wherein the water content of the hydrous magnesium silicate is 1 to 4 mass %.

8. A method for analyzing dioxins contained in an aliphatic hydrocarbon solvent solution of dioxins, comprising the step of separately analyzing, by gas chromatography or bioassay, a first analytical sample and a second analytical sample prepared by the method for preparing a sample for analyzing dioxins described in claim 7.

9. An apparatus for fractionating dioxins contained in an aliphatic hydrocarbon solvent solution of dioxins, comprising a first tubular body with both ends open and filled with a first layer made of a first agent containing hydrous magnesium silicate, wherein the water content of the hydrous magnesium silicate is 1 to 4% by mass.

10. The apparatus for fractionating dioxins according to claim 9, wherein the first agent further comprises a carbon material mixed with the hydrous magnesium silicate.

11. The dioxins fractionation device according to claim 9, wherein the hydrous magnesium silicate is hydrous activated magnesium silicate.

12. A dioxins fractionation device according to any one of claims 9 to 11, further comprising a second tubular body with both ends open and filled with a second layer made of a second agent containing at least one of an alumina-based material and a zirconia-based material, one end of the second tubular body being detachably connectable to one end of the first tubular body.

13. A fractionation agent for dioxins contained in an aliphatic hydrocarbon solvent solution of dioxins, the fractionation agent comprising hydrous magnesium silicate, the hydrous magnesium silicate having a water content of 1 to 4 mass %.

14. The dioxins fractionation agent according to claim 13, further comprising a carbon material mixed with the hydrous magnesium silicate.

15. The dioxin fractionating agent according to claim 13 or 14, wherein the hydrous magnesium silicate is hydrous activated magnesium silicate.

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