JP7015705B2 - Extraction method of polychlorinated biphenyls - Google Patents

Description

The present invention relates to a method for extracting polychlorinated biphenyls, particularly a method for extracting polychlorinated biphenyls from a solution containing polychlorinated biphenyls.

Sediment, soil, incinerated ash produced in incinerators, food, biological samples such as blood and breast milk, environmental water such as seawater, river water, lake water and groundwater, industrial wastewater, air, exhaust gas from incinerators, etc. , Evaluation of the pollution status by polychlorinated biphenyls (hereinafter, may be referred to as "PCBs") known as environmental pollutants having strong toxicity to living organisms is required.

In the evaluation of the contamination status by PCBs, PCBs are usually extracted from the sample to be evaluated using a solvent such as an aliphatic hydrocarbon solvent such as hexane or an aromatic hydrocarbon solvent such as toluene, and this extraction is obtained. The PCBs solution is analyzed using a highly sensitive analytical instrument such as a gas chromatograph mass analysis method (GC / MS method) or a gas chromatograph electron capture detection method (GC / ECD method).

PCBs are a general term for biphenyls in which hydrogen atoms are replaced by chlorine atoms, and there are 10 types from monochromobiphenyl to decachlorobiphenyl in terms of the number of substituted chlorines, and 209 depending on the chlorine substitution position. There are types. Therefore, in order to analyze PCBs with high accuracy, the solution of PCBs contains interfering components (contamination components) that affect the measurement results without impairing the recovery rate of each homologue of PCBs when measuring with an analytical instrument. High-precision pretreatment that can be removed is required.

As one of the pretreatment methods, Non-Patent Document 1 describes a pretreatment method for a hexane solution obtained by extracting PCBs from sediment. In this pretreatment method, sulfuric acid treatment is repeated for the hexane solution as a sample, and the hexane solution after this treatment is washed with a saturated sodium chloride solution and concentrated. Then, the concentrated hexane solution is further treated with a silica gel column containing sodium sulfate, and PCBs are extracted from the silica gel column using hexane. Although this pretreatment method can effectively remove contaminants without impairing the recovery rate of each homologue of PCBs, it requires a lot of manual work and takes a long time to complete. The number of samples that can be processed during the actual operating hours of the day is limited. Therefore, it is difficult to treat a large number of samples generated daily by this pretreatment method quickly and economically.

August 2012 Sediment survey method, Water and Air Environment Bureau, Ministry of the Environment (II.6.4)

The present invention makes it possible to extract PCBs from a solution containing PCBs in a short time by a simple operation.

The present invention relates to a method for extracting polychlorinated biphenyls from a solution containing polychlorinated biphenyls. This extraction method is a first layer including a holding layer formed by using a material that is inactive to polybiphenyl chlorides and has a liquid permeability and is permeable to the above solution, and a silica gel sulfate layer. Step 1 of adding the above solution to the holding layer, step 2 of supplying an aliphatic hydrocarbon solvent from the holding layer side to the first layer to which the solution is added and passing it through, and the first alumina layer and the second alumina layer. Step 3 in which the aliphatic hydrocarbon solvent that has passed through the first layer is supplied from the first alumina layer side and passed through the second layer containing the above, and polychloride to the second layer through which the aliphatic hydrocarbon solvent has passed. It includes a step 4 of supplying and passing an extraction solvent for biphenyls, and a step 5 of securing an extraction solvent that has passed through the second layer. The second alumina layer used here contains aluminum oxide containing at least one metal oxide selected from the group consisting of nickel oxide and silver oxide. Further, in the steps 1 and 2 of this extraction method, the temperature of the first layer is set to less than 35 ° C.

In this extraction method, the solution containing the polybiphenyl chloride added to the holding layer in step 1 is dissolved in the aliphatic hydrocarbon solvent supplied in step 2 and together with the aliphatic hydrocarbon solvent, the holding layer and the sulfuric acid silica gel layer. In this order, it passes through the first layer, and in step 3, it passes through the second layer together with the aliphatic hydrocarbon solvent. At this time, since the temperature of the first layer of the polychlorinated biphenyls contained in the above solution is set to less than 35 ° C. in steps 1 and 2, decomposition in the first layer, particularly the silica gel sulfate layer, is suppressed. , It is captured in the first alumina layer or the second alumina layer of the second layer depending on the type. In addition, some of the contaminants other than polychlorinated biphenyls are captured in the first layer, and the residue passes through the first and second layers together with the aliphatic hydrocarbon solvent. Therefore, if the extraction solvent supplied to the second layer in step 4 is secured in step 5, a solution of the extraction solvent for polychlorinated biphenyls can be obtained.

The holding layer of the first layer used in this extraction method is formed by using, for example, silica gel.

In this extraction method, in step 4, it is preferable to supply and pass the extraction solvent to the second layer in the direction opposite to the passing direction of the aliphatic hydrocarbon solvent. Further, it is preferable to remove the aliphatic hydrocarbon solvent remaining in the second layer before supplying the extraction solvent to the second layer in step 4.

The solution from which polychlorinated biphenyls can be extracted by this extraction method is, for example, from a material layer at the bottom of the aquatic zone or on the surface of land, food, biological samples, environmental water, wastewater, incineration ash, or a collector of gas-containing substances. Polychlorinated biphenyls are extracted using a solvent.

The present invention according to another aspect relates to a column for extracting polychlorinated biphenyls from a solution containing polychlorinated biphenyls. This column is filled with a first layer containing a holding layer formed of a material that is permeable to liquid and is permeable to a solution and is inert to polychlorinated biphenyls, and a silica gel sulfate layer. The first column is provided with a second column packed with a second layer including a first alumina layer and a second alumina layer, which are detachably connected to the first column. Here, the second alumina layer contains aluminum oxide containing at least one metal oxide selected from the group consisting of nickel oxide and silver oxide, and the second column has a first end on the first alumina layer side. It is detachably connected to the end of the column on the silica gel sulfate layer side.

The retaining layer used in this column is formed using, for example, silica gel. Further, it is preferable that the second column is filled so that the first alumina layer and the second alumina layer have the same volume.

The column for extracting polychlorinated biphenyls according to the present invention can be used in the extraction method of the present invention.

Since the method for extracting polychlorinated biphenyls according to the present invention includes the above-mentioned steps 1 to 5, polychlorinated biphenyls can be extracted from a solution containing polychlorinated biphenyls in a short time by a simple operation. ..

The schematic diagram of an example of a column which can be used in the extraction method of polychlorinated biphenyls which concerns on this invention. The figure which shows one step of the extraction method using the said column. The figure which shows the other steps of the extraction method using the said column. The figure which shows still another process of the extraction method using the said column. The figure which shows still another process of the extraction method using the said column. The graph which shows the result of Experimental Example I.

The method for extracting polychlorinated biphenyls (PCBs) according to the present invention relates to a method for extracting PCBs from a solution containing PCBs.

The PCB-containing solution that is the target of this extraction method is not particularly limited, but usually requires evaluation of contamination by PCBs, for example, the bottom of the aquatic area such as sediment or soil, or the surface of land. Material layers, agricultural products, foods such as meat and seafood, body fluids such as breast milk and blood, biological samples such as organs and tissues, environmental water such as river water, lake water and groundwater, wastewater such as industrial wastewater and domestic wastewater, Solvents (usually aliphatic hydrocarbons such as hexane) from incineration ash produced in incineration facilities or collectors such as filters that collect inclusions in gases such as the environmental atmosphere and exhaust gas discharged from incineration facilities. It is a solution obtained by extracting PCBs using a solvent or a hydrophobic organic solvent such as an aromatic hydrocarbon solvent such as toluene).

With reference to FIG. 1, an example of an extraction column used for carrying out the method for extracting PCBs according to the present invention will be described. In the figure, the extraction column 1 mainly includes a connecting member 30 for connecting the first column 10, the second column 20, and both columns 10, 20 and extends from the first column 10 to the second column 20. It forms a series of flow path systems.

The first column 10 is formed in a cylindrical shape in which the outer diameter and the inner diameter of the lower end portion 10a are reduced, and has openings 11 and 12 at the upper end portion and the lower end portion, respectively. The first column 10 is formed by using, for example, glass or a resin material having solvent resistance, and a space 13 is provided on the opening 11 side to fill the first layer 14. The first layer 14 includes the holding layer 15 and the silica gel sulfate layer 16 in this order from the opening 11 side to the opening 12 side.

The holding layer 15 is a layer that has liquid permeability and allows a PCB-containing solution to permeate, and is formed by using a material that is inert to the PCBs. The material for forming the holding layer 15 is usually granular silica gel, granular active silica gel, granular or amorphous silicon dioxide, cotton-like glass fiber, cotton-like quartz glass, granular fluorodil (magnesium silicate), and the like. A resin material such as granular active white clay, diatomaceous earth such as Celite, polyethylene resin, polypropylene resin or polytetrafluoroethylene resin, polyvinylidene fluoride resin or fluororesin such as perfluoroalkoxyalkane resin is molded into a particle shape or the like. Things can be mentioned. Two or more kinds of these materials may be used in combination. In this case, the materials may be mixed and used, or may be arranged in multiple layers in the vertical direction. A preferred material is silica gel because it is inexpensively available and easy to fill in the first column 10.

The silica gel sulfate layer 16 is a layer made of silica gel sulfate. The silica gel sulfate used here is prepared by uniformly adding concentrated sulfuric acid to the surface of silica gel (preferably active silica gel).

In the first layer 14, the packing density of the material forming the holding layer 15 is usually preferably set to 0.1 to 2.5 g / cm ³ , preferably 0.2 to 1 g / cm ³ . More preferred. When the packing density is less than 0.1 g / cm ³ , when the PCB-containing solution is added to the first layer 14, the added PCB-containing solution is difficult to be retained in the holding layer 15, and within a short period of time. There is a possibility that the retaining layer 15 will permeate and migrate to the sulfuric acid silica gel layer 16. On the contrary, when the packing density exceeds 2.5 g / cm ³ , it becomes difficult for the aliphatic hydrocarbon solvent to pass through the holding layer 15 when the aliphatic hydrocarbon solvent is supplied to the first layer 14. there is a possibility.

In the first layer 14, the packing density of the silica gel sulfate forming the silica gel sulfate layer 16 is usually preferably set to 0.2 to 2.0 g / cm ³ , preferably 0.5 to 1.0 g / cm ³ . It is more preferable to set it. When the packing density is less than 0.2 g / cm ³ , the contaminating components other than the PCBs contained in the PCB-containing solution are less likely to be captured by the sulfuric acid silica gel layer 16, and the PCBs and the contaminating components in the PCB-containing solution become difficult to be captured. Can be difficult to separate. On the contrary, when the packing density exceeds 2.0 g / cm ³ , when the aliphatic hydrocarbon solvent is supplied to the first layer 14, the aliphatic hydrocarbon solvent is difficult to pass through the sulfuric acid silica gel layer 16. There is a possibility of becoming.

In the first layer 14, the filling amount of the holding layer 15 and the silica gel sulfate layer 16 depends on the amount (sample amount) of the PCB-containing solution applied to the extraction column 1, but for example, when the sample amount is 2 mL or less, the holding layer The filling amount of 15 is usually preferably set to 0.2 to 3 mL, more preferably 0.5 to 1.5 mL. When this filling amount is less than 0.2 mL, when the PCB-containing solution is added to the first layer 14, the added PCB-containing solution is difficult to be retained in the holding layer 15, and the holding layer is quickly retained. There is a possibility that it will permeate through 15 and migrate to the sulfuric acid silica gel layer 16. On the contrary, when the filling amount exceeds 3 mL, it may be difficult for the aliphatic hydrocarbon solvent to pass through the holding layer 15 when the aliphatic hydrocarbon solvent is supplied to the first layer 14. Similarly, when the sample amount is 2 mL or less, the filling amount of the silica gel sulfate forming the silica gel sulfate layer 16 is usually preferably set to 1 to 10 mL, and more preferably set to 3 to 6 mL. When this filling amount is less than 1 mL, contaminants other than PCBs contained in the PCB-containing solution are less likely to be captured by the silica gel sulfate layer 16, and separation of PCBs and contaminants in the PCB-containing solution becomes difficult. There is a possibility of becoming. On the contrary, when the filling amount exceeds 10 mL, it may be difficult for the aliphatic hydrocarbon solvent to pass through the silica gel sulfate layer 16 when the aliphatic hydrocarbon solvent is supplied to the first layer 14. ..

The second column 20 is formed in a cylindrical shape, and has openings 21 and 22 at the upper end and the lower end, respectively. The second column 20 is formed of, for example, glass or a resin material having solvent resistance and heat resistance, and is filled with a second layer 23 for capturing PCBs. The outer diameter and inner diameter of the second column 20 are usually preferably set to be larger than these diameters of the lower end portion 10a of the first column 10, but can also be set to be the same as these diameters of the lower end portion 10a. ..

The second layer 23 is unevenly filled toward the opening 21 so that the gap 24 is formed on the opening 22 side of the second column 20, and the first layer 23 is first directed from the opening 21 side toward the opening 22 side. The alumina layer 25 and the second alumina layer 26 are included in this order.

The first alumina layer 25 is formed by using powdery or particulate aluminum oxide. The aluminum oxide used here is usually preferably intermediate alumina such as γ-alumina, δ-alumina or θ-alumina, and may be basic, neutral or acidic. Further, the activity of aluminum oxide is not limited, and aluminum oxide having various activities can be used in the first alumina layer 25.

The packing density of the first alumina layer 25 is usually preferably set to 0.4 to 2 g / cm ³ , and more preferably 0.5 to 1.6 g / cm ³ . If the packing density is less than 0.4 g / cm ³ , it may be difficult to capture and recover the PCBs having a small chlorine content in the PCB-containing solution in the second layer 23. There is. On the contrary, when the packing density exceeds 2 g / cm ³ , there is a possibility that the recovery of PCBs becomes insufficient or the pressure loss becomes high when the PCBs are extracted from the second layer 23 by the extraction solvent described later. There is.

The second alumina layer 26 is formed by using powdery or particulate aluminum oxide. However, the aluminum oxide used here contains at least one metal oxide selected from the group consisting of nickel oxide and silver oxide. Such metal oxide-containing aluminum oxide is obtained by mixing an aqueous solution of at least one metal salt selected from the group consisting of nickel salts and silver salts with aluminum oxide, and evaporating water from this mixture to dry it. It is obtained by firing the resulting solid in an air atmosphere, where aluminum oxide particles are predominantly directly on at least a portion of its surface or in a metal layer (ie, nickel derived from the metal salt used). Alternatively, it is presumed to have a metal oxide indirectly across the silver layer.).

The aluminum oxide used in the preparation of the metal oxide-containing aluminum oxide is in the form of powder or particles, and usually, intermediate alumina such as γ-alumina, δ-alumina or θ-alumina is preferable, and basicity is also preferable. , Neutral or acidic. Further, the activity of aluminum oxide is not limited, and aluminum oxide having various activities can be used.

Nickel salts, which are metal salts, usually have nickel nitrate, nickel chlorate, nickel perchlorate, nickel formate, nickel acetate, nickel bromide, nickel bromide, because they have good solubility and decomposability in water. Nickel fluoride or nickel iodide is used. Two or more kinds of these nickel salts may be used in combination.

As the silver salt which is a metal salt, silver nitrate, silver chlorate, silver perchlorate, silver acetate or silver fluoride is usually used because of its good solubility and decomposability in water. Two or more kinds of these silver salts may be used in combination.

The concentration of the metal salt in the aqueous solution of the metal salt is not particularly limited. However, the mixing amount of the metal salt aqueous solution with aluminum oxide is usually such that the amount (mmol) of the metal (at least one of nickel and silver) per mass (g) of aluminum oxide is 0.1 to 10 mmol. It is preferable to set it, and it is more preferable to set it to 0.5 to 5 mmol.

Firing in an air atmosphere is a treatment for producing a metal oxide, and this treatment gives the desired metal oxide-containing aluminum oxide. The calcination is usually carried out in an air atmosphere, but it can also be carried out in an air atmosphere followed by a nitrogen atmosphere. The surface of aluminum oxide can be activated by firing in a nitrogen atmosphere. In addition, it is possible to suppress the adsorption of water and oxygen to the generated metal oxide-containing aluminum oxide in the process of lowering the temperature to room temperature after firing, and the activity of the metal oxide-containing aluminum oxide produced thereby is maintained or stabilized. Can be transformed into.

Both firing in an air atmosphere and firing in a nitrogen atmosphere are preferably performed at 1,000 ° C. or lower.

The packing density of the second alumina layer 26 is usually preferably set to 0.4 to 2 g / cm ³ , and more preferably 0.5 to 1.6 g / cm ³ . When the packing density is less than 0.4 g / cm ³ , it becomes difficult for PCBs contained in the PCB-containing solution, especially PCBs having a large chlorine content, to be captured in the second layer 23, and the recovery rate may decrease. There is. On the contrary, when the packing density exceeds 2 g / cm ³ , there is a possibility that the recovery of PCBs becomes insufficient or the pressure loss becomes high when the PCBs are extracted from the second layer 23 by the extraction solvent described later. There is.

In the second layer 23, the filling ratio of the first alumina layer 25 and the second alumina layer 26 is usually 3: 5 to 5: 3 in terms of volume ratio (first alumina layer 25: second alumina layer 26). However, it is particularly preferable to set both to have the same volume. When the filling ratio of the first alumina layer 25 is less than 3 in terms of the volume ratio, it is difficult to capture and recover the PCBs having a small chlorine content among the PCBs contained in the PCB-containing solution in the second layer 23. May become. On the contrary, when the filling ratio of the first alumina layer 25 exceeds 5 in the above volume ratio, the PCBs having a large chlorine content among the PCBs contained in the PCB-containing solution are captured and recovered in the second layer 23. Can be difficult.

The connecting member 30 is a tubular member into which the lower end portion 10a of the first column 10 and the upper end portion of the second column 20 can be inserted, and is stable and heat resistant to various solvents, particularly hydrocarbon solvents. It is formed using a material, for example, a resin material having solvent resistance and heat resistance. The connecting member 30 detachably connects the lower end portion 10a of the first column 10 and the upper end portion of the second column 20. Therefore, in the extraction column 1, the first column 10 and the second column 20 are separable.

The size of the extraction column 1 can be appropriately set according to the amount of the PCB-containing solution to be extracted of the PCBs, but the PCBs are used to measure the concentration of the PCBs contained in the PCB-containing solution. When performing pretreatment to remove contaminants from the class-containing solution, it is sufficient to collect a small amount or a small amount of sample from the PCB-containing solution and apply the extraction method described later. Therefore, the extraction column 1 is made smaller accordingly. Can be set to. For example, when PCBs are extracted for measuring the concentration of PCBs in a sample of about 1.0 to 500 mg collected from a PCB-containing solution, the size of the first column 10 in the extraction column 1 (first). The size of the portion that can be filled with the layer 14) is preferably 10 to 20 mm in inner diameter and 30 to 110 mm in length, and the size of the second column 20 (the size of the portion that can be filled with the second layer 23). The inner diameter is preferably 2.0 to 10.0 mm and the length is preferably 10 to 200 mm.

Next, a method for extracting PCBs from a PCB-containing solution using the above-mentioned extraction column 1 will be described. In this extraction method, first, as shown in FIG. 2, the extraction column 1 is erected so that the first column 10 is on the upper side, and a solvent for receiving the aliphatic hydrocarbon solvent described later that passes through the extraction column 1. The container 40 is placed at the lower end of the second column 20.

Next, a small amount or a small amount (usually about 1.0 to 500 mg) of a sample is taken from the PCB-containing solution, and this sample is collected from the opening 11 at the upper end of the first column 10 to the holding layer 15 of the first layer 14. Add to (step 1). The added sample gradually permeates into the holding layer 15 and is held in the holding layer 15. As a result, even if it may take some time to move to the next step after the addition of the sample, the possibility that the PCBs in the sample come into direct contact with the silica gel sulfate layer 16 during that time is reduced. As a result, the decomposition of PCBs in the sample due to the action of silica gel sulfate, especially PCBs with 1 or 2 chlorine numbers, is suppressed, and the recovery rate of all PCBs including PCBs with low chlorine numbers in this extraction method can be improved. Can be enhanced.

In this step, the sample is added to the holding layer 15 and a hydrocarbon solvent that can dissolve the sample and is miscible with the aliphatic hydrocarbon solvent described later is added to the holding layer 15 to dilute the sample. You may. Normally, the hydrocarbon solvent may be added immediately after the sample is added to the holding layer 15, but it can also be added to the sample in advance.

Next, as shown in FIG. 3, a reservoir 50 for supplying a solvent to the first column 10 is attached to the opening 11 on the upper end side of the first column 10, and an aliphatic hydrocarbon is installed in the reservoir 50. Store the solvent. Then, a pressurizing device 51 for pressurizing the inside of the reservoir 50 is attached to the reservoir 50, and the inside of the reservoir 50 is pressurized by operating the pump 52. As a result, the aliphatic hydrocarbon solvent stored in the reservoir 50 is continuously and gradually supplied into the first column 10 and passes through the first layer 14 (step 2).

At this time, the aliphatic hydrocarbon solvent supplied to the first column 10 permeates into the holding layer 15 while accumulating in the space 13, and while dissolving the held sample, the holding layer 15 and the sulfuric acid silica gel layer 16 are subjected to this. Pass in order. The aliphatic hydrocarbon solvent that has passed through the first layer 14 in this way flows from the opening 12 of the first column 10 to the connecting member 30, and flows from the opening 21 into the second column 20. In this process, when the aliphatic hydrocarbon solvent in which the sample held in the holding layer 15 is dissolved passes through the silica gel sulfate layer 16, some of the contaminants other than PCBs are captured in the silica gel sulfate layer 16.

The aliphatic hydrocarbon solvent flowing into the second column 20 passes through the second layer 23, is discharged from the opening 22, and is received by the solvent container 40 (step 3). At this time, the PCBs dissolved in the aliphatic hydrocarbon solvent from the first column 10 are captured by the first alumina layer 25 or the second alumina layer 26 of the second layer 23 depending on the type, and the second layer. It is kept in 23. In the tendency, among the PCBs, the PCBs having a low chlorine number of about 1 to 2 are mainly captured by the first alumina layer 25, and the other PCBs having a high chlorine number are mainly captured. It is captured by the second alumina layer 26 and retained in the second layer 23.

Here, the PCBs dissolved in the aliphatic hydrocarbon solvent are easily captured by the first alumina layer 25 or the second alumina layer 26 depending on the type thereof, so that the first alumina layer 25 and the second alumina layer 26 are easily captured. It is mainly held at a portion of the inside near the opening 21. Further, the residual contaminating components that were not captured in the first layer 14 and flowed to the second column 20 together with the PCBs pass through the second layer 23 together with the aliphatic hydrocarbon solvent and flow out to the solvent container 40.

The aliphatic hydrocarbon solvent stored in the reservoir 50 is capable of dissolving PCBs in the sample, and is usually an aliphatic saturated hydrocarbon solvent having 5 to 8 carbon atoms, for example, n-pentane, n-. Hexane, n-heptane, n-octane, isooctane, cyclohexane and the like. In particular, n-hexane is preferable. The amount of the aliphatic hydrocarbon solvent stored in the reservoir 50, that is, the total amount of the aliphatic hydrocarbon solvent supplied to the first column 10 is usually preferably set to 10 to 120 mL. Further, the supply rate of the aliphatic hydrocarbon solvent from the reservoir 50 is usually preferably set to 0.2 to 5.0 mL / min by adjusting the pressurized state in the reservoir 50 by the pump 52.

In the above steps 1 to 3, particularly steps 1 and 2, the temperature of the first layer 14 is set to less than 35 ° C, preferably 30 ° C or lower, and more preferably 28 ° C or lower. Therefore, when this extraction operation is performed in a high temperature environment and the temperature of the first layer 14 becomes 35 ° C. or higher, the temperature of the first layer 14 is set to 35 by using a coolant or a cooling device. Control below ° C. When the temperature of the first layer 14 is 35 ° C. or higher, PCBs having a low chlorine content are easily decomposed or adsorbed by the silica gel sulfate layer 16, and the extraction rate (recovery rate) of PCBs having a low chlorine content is high. descend. The lower limit of the temperature of the first layer 14 is not particularly limited as long as it is within a temperature range in which the aliphatic hydrocarbon solvent can smoothly flow, but it is usually preferably about 10 ° C.

Next, the second column 20 and the first column 10 are separated by removing the first column 10 from the connecting member 30. Then, as shown in FIG. 4, the second column 20 is turned upside down, and the heating device 60 is arranged around the second layer 23. Further, as shown in FIG. 4, the pressurizing device 51 is attached to the opening 22 which has been moved to the upper end side of the second column 20 by being turned upside down. Then, the pump 52 is operated while heating the entire second layer 23 to about 35 to 90 ° C. by the heating device 60, and the inert gas such as nitrogen gas or air is supplied from the opening 22 into the second column 20. .. As a result, the solvent such as the aliphatic hydrocarbon solvent remaining in the second column 20 is discharged from the opening 21 which has moved to the lower end side of the second column 20 together with the inert gas and the like. As a result, the solvent such as the aliphatic hydrocarbon solvent is removed from the second layer 23, and the second layer 23 is dried. The heating device 60 used here is a heater, a Pelche element, or the like, and can heat the entire second layer 23 in the second column 20 to a required temperature.

In FIG. 4, the second column 20 is displayed with the connecting member 30 attached, but the connecting member 30 may be removed from the second column 20.

Next, the pressurizing device 51 is removed from the second column 20, and as shown in FIG. 5, the PCBs can be dissolved into the void 24 from the opening 22 of the second column 20 which is erected while being turned upside down. Supply the solvent. The supplied extraction solvent accumulates in the void 24 and gradually permeates into the second layer 23 by its own weight.

The extraction solvent that has penetrated into the second layer 23 passes through the second layer 23 and flows out from the opening 21 that has moved to the lower end side of the second column 20 (step 4). At this time, the extraction solvent dissolves the PCBs trapped in each of the first alumina layer 25 and the second alumina layer 26 of the second layer 23, and flows out from the opening 21 together with the PCBs. Therefore, if the extraction solvent flowing out from the opening 21 is secured, a PCB extraction solvent solution, that is, a target PCB extraction solution can be obtained (step 5).

Here, since the PCBs are mainly captured in the vicinity of the openings 21 of the first alumina layer 25 and the second alumina layer 26, substantially the total amount of the PCBs captured in the second layer 23. Is in a state of being dissolved mainly in the extraction solvent of the early to middle stage portion flowing out from the second column 20. Therefore, since the target PCB extract can be obtained only by securing the extraction solvent for the early to middle portion flowing out from the opening 21, the amount of the extract can be reduced to a small amount that can be easily used in the analysis operation described later. It can be suppressed. Further, since the extract of PCBs obtained here is obtained by removing the aliphatic hydrocarbon solvent from the second layer 23 and then supplying the extraction solvent to the second column 20, the aliphatic hydrocarbon is obtained. It can be a high-purity extract with less contamination of the hydrocarbon solvent and the contaminants dissolved in it.

According to the extraction method according to the present embodiment, the above-mentioned extract can be usually obtained in a short time of about 0.5 to 1 hour from the start of work (step 1).

When extracting PCBs from the second layer 23, it is preferable to supply the extraction solvent while heating the entire second layer 23 with the heating device 60. The heating temperature of the second layer 23 is usually preferably set to at least 35 ° C, more preferably 60 ° C or higher. The upper limit of the heating temperature is not particularly limited, but is usually about 90 ° C. When the second layer 23 is heated at the time of extraction, the entire amount of the PCBs captured in the second layer 23 can be easily extracted with a smaller amount of the extraction solvent. Therefore, the amount of the PCB extracts is used in the analysis operation described later. It can be controlled to a smaller amount than it is easy.

The extraction solvent for extracting the PCBs from the second layer 23 can be selected according to the method for analyzing the PCBs. When the gas chromatography method is adopted as the analysis method, a hydrophobic solvent capable of dissolving PCBs is used as the extraction solvent. Examples of such hydrophobic solvents include toluene, a mixed solvent of toluene and an aliphatic hydrocarbon solvent (for example, n-pentane, n-hexane, n-heptane, n-octane, isooctane, cyclohexane, etc.) and an organic solvent. A mixed solvent of a chlorine-based solvent (for example, dichloromethane, trichloromethane, tetrachloromethane, etc.) and an aliphatic hydrocarbon solvent (for example, n-pentane, n-hexane, n-heptane, n-octane, isooctane, cyclohexane, etc.). And so on. Of these, toluene, which can extract PCBs from the second layer 23 with a smaller amount of use, is preferable.

When a hydrophobic solvent is used as the extraction solvent, the extract obtained in step 5 can be used as it is or by concentrating it as needed as a sample for analysis by a gas chromatography method. The gas chromatography method can be carried out by using gas chromatography equipped with various detectors, but usually includes a gas chromatograph mass analysis method (GC / MS / MS method) having good sensitivity to PCBs. In the sense, the GC / MS method) or the gas chromatograph electron capture detection method (GC / ECD method) is preferable. In particular, according to the GC / MS method, PCBs contained in an analysis sample can be quantified in units of isomers or homologues, and more findings can be obtained from the analysis results.

When the bioassay method is adopted as the analysis method, a hydrophilic solvent capable of dissolving PCBs is used as the extraction solvent. Examples of such a hydrophilic solvent include dimethyl sulfoxide (DMSO) and methanol.

When a hydrophilic solvent is used as the extraction solvent, the extract obtained in step 5 can be used as it is as a sample for analysis in a bioassay method such as an immunoassay method or an ELISA method.

The above-mentioned extraction method can extract a wide range of types of PCBs contained in a PCB-containing solution, from PCBs having a chlorine number of 1 to PCBs having a chlorine number of 10, with a high recovery rate. When the extract obtained by using the above is used as a sample for analysis, the PCBs contained in the PCB-containing solution can be measured with high accuracy. For this reason, the extraction method described above involves a variety of samples that may contain a wide variety of PCBs with chlorine counts from 1 to 10, especially material layers at the bottom of the aquatic zone or on land surfaces such as sediment and soil. , Foods, biological samples, environmental water, wastewater, incineration ash or in the preparation of samples for analysis of PCBs contained in gases such as exhaust gas and air.

The above-described embodiment can be modified as follows, for example.
(1) The first column 10 may further include an auxiliary layer formed below the first layer 14 using a material having liquid permeability and being inert to PCBs. As the material for forming the auxiliary layer, the same material as that for forming the holding layer 15 can be usually used. When the auxiliary layer is provided, a part of the contaminant components that have passed through the first layer 14 together with the PCBs without being captured by the silica gel sulfate layer 16 can be separated in the auxiliary layer, and the PCBs and the contaminant components are higher. Can be separated with precision.

(2) The second column 20 is filled with the second layer 23 so that the void 24 is formed on the opening 22 side, and the same void can be provided on the opening 21 side as well. In this case, since the aliphatic hydrocarbon solvent that has passed through the first column 10 can be stored in the void on the opening 21 side, the aliphatic hydrocarbon solvent can be stably supplied to the second layer 23. ..

(3) The second alumina layer 26 of the second layer 23 is the same as that used in other materials, for example, the first alumina layer 25, together with the metal oxide-containing aluminum oxide, to the extent that the catchability of PCBs is not impaired. It may contain aluminum oxide, cobalt oxide, zirconia oxide, cerium oxide, titanium oxide, iron oxide and the like. As the other material, two or more kinds may be used.

(4) In the above-described embodiment, the first column 10 and the second column 20 are detachably connected by a connecting member 30, but other means may be used for the connection between the columns. .. For example, a sliding portion can be provided at the connecting portion of the columns, and the columns can be detachably connected by connecting the sliding portions.

(5) In the above-described embodiment, the aliphatic hydrocarbon solvent stored in the reservoir 50 is supplied to the first column 10 by pressurizing it with the pressurizing device 51, but the aliphatic hydrocarbon solvent in the reservoir 50 is supplied. It is also possible to naturally flow down to the first column 10 by its own weight without using the pressurizing device 51. Further, the aliphatic hydrocarbon solvent can also be supplied to the first column 10 by using a metering pump such as a syringe pump or a suction device. Further, the aliphatic hydrocarbon solvent can also be supplied to the first column 10 by hand using an instrument such as a pipette.

(6) In the above-described embodiment, the extraction solvent supplied to the void 24 of the second column 20 is naturally supplied to the second layer 23 by its own weight, but the opening 21 of the second column 20 or It is also possible to install a reservoir for supplying the extraction solvent to the opening 22 and change the extraction solvent stored in this reservoir so that the extraction solvent is naturally supplied to the second column 20 by its own weight. Further, the extraction solvent can also be supplied to the second column 20 by using a metering pump such as a syringe pump or a suction device.

(7) In the above-described embodiment, the second layer 23 is heated by the heating device 60 while supplying an inert gas or the like into the second column 20, and the second layer 23 is dried. The layer 23 may be dried without heating. However, by heating, the solvent remaining in the second column 20 can be easily dissipated, and the second layer 23 can be dried in a shorter time.

(8) In the above-described embodiment, the second column 20 is separated from the first column 10 when the inert gas or the like or the extraction solvent is supplied to the second column 20, but the second column 20 is the first. It is also possible to change the second column 20 so that an inert gas or the like or an extraction solvent can be supplied without separating from the first column 10. This can be realized, for example, by connecting the first column 10 and the second column 20 by using a connecting device having a flow path switching valve. The flow path switching valve used in this case has an introduction port for an inert gas or the like and an discharge port for an extraction solvent, and is not a flow path for connecting the first column 10 and the second column 20. It has a flow path for connecting the introduction port of the active gas or the like and the second column 20 and a flow path for connecting the second column 20 and the discharge port of the extraction solvent, and by switching the flow path, Supply of the aliphatic hydrocarbon solvent from the first column 10 to the second column 20, introduction of the inert gas from the introduction port of the inert gas or the like to the second column 20, and the opening 22 to the second column 20. One of the discharges of the supplied extraction solvent from the discharge port can be selected.

[Experimental example]
[Preparation of test sample]
<Sample A>
50 μL of the PCB standard substance solution (trade name “BP-MS” of Wellington Laboratories) and 100 μL of the standard substance solution in PCB (trade name “MBP-MXP” of Wellington Laboratories) are mixed in a microtube, and sample A is used. Was prepared.

<Sample B>
Sample B was prepared by mixing 100 μL of a standard substance solution in PCB (trade name “MBP-MXP” manufactured by Wellington Laboratories) and 100 μL of isooctane in a microtube.

<Sample C>
50 μL of PCB standard substance (trade name “COMPLEHENSIVE NATIVE PCB MIXTURE” of CIL), 100 μL of standard substance solution in PCB (trade name “MBP-MXP” of Wellington Laboratories) and 100 μL of isooctane are mixed in a microtube, and sample C is used. Was prepared.

<Sample D>
Weigh 10 g of the river bottom sediment certification standard substance "JSAC0432" for analysis of dioxins and PCB homologues, and add 1 mL of the standard substance solution in PCB (trade name "MBP-MXP" of Wellington Laboratories) to the eggplant type. Placed in a flask. About 1.2 M of potassium hydroxide / ethanol solution was added to this eggplant-shaped flask, and a reflux condenser was attached to the flask, and the mixture was heat-decomposed in a boiling water bath for about 1 hour. Then, after cooling the contents of the eggplant-shaped flask, 50 mL of n-hexane was added, and the mixture was vigorously shaken with a stopper attached, and then the mixed solution in the eggplant-shaped flask was filtered under reduced pressure using a glass fiber filter paper. On the other hand, the residue in the eggplant-shaped flask was vigorously shaken by adding 20 mL of an ethanol / n-hexane (1/1) mixed solution, and then filtered under reduced pressure in the same manner. The filtrates obtained by these vacuum filtrations were put into a separatory funnel (A) and combined. Further, the residue in the eggplant-shaped flask was washed into a filtration device using 30 mL of n-hexane, and the filtrate was transferred to a separatory funnel (A). 50 mL of water was added to this separating funnel (A), and the mixture was shaken for 10 minutes for extraction, and the aqueous layer after standing was transferred to another separating funnel (B). 50 mL of n-hexane was added to the separatory funnel (B) and shaken again for extraction, and the hexane layer was combined with the hexane solution (oil layer) of the separatory funnel (A). Glass wool was packed in the lower part of the glass funnel, and the hexane solution of the separatory funnel (A) was passed through the laminated product of anhydrous sodium sulfate to dehydrate it. Then, a sample D was obtained by concentrating the dehydrated hexane solution to 5 mL using a rotary evaporator.

[Preparation of metal oxide-containing aluminum oxide]
An aqueous solution prepared by dissolving 3.39 g of silver nitrate in 10 g of distilled water is prepared, and a mixed solution is prepared by mixing the entire amount of this aqueous solution with 10.0 g of aluminum oxide (trade name "MP Aluminuma B Super I" of MP Biomedicals). Obtained. In this mixed solution, the metal concentration (silver concentration) per mass (g) of aluminum oxide is 2 mmol.

Water was evaporated from the mixture using a rotary evaporator to dry the solids. This solid content was placed in a tube furnace controlled to have a temperature of 1,000 ° C. or lower and fired under an air flow of 200 mL / min for 2.5 hours, and then heating of the tube furnace was stopped under a nitrogen stream to stop the heating of the tube furnace. Was cooled to room temperature. As a result, aluminum oxide containing silver oxide was obtained.

[Experimental Example I]
A column with an inner diameter of 13 mm and a length of 70 mm is filled with 3.3 g of silica gel sulfate (trade name "Rapiana Sulfate Silica" of Miura Kogyo Co., Ltd.) so that the height is 35 mm, and 0.5 g of silica gel (0.5 g of silica gel) is filled therein. The first layer was formed by filling the product name "silica gel 60 (spherical)" of Kanto Chemical Co., Inc. so that the height was 10 mm, and the first column was prepared. The inner diameter was 4.6 mm and the length was 4.6 mm. 0.7 g of metal oxide-containing aluminum oxide is filled in a 100 mm column so as to have a height of 35 mm, and aluminum oxide (trade name "MP Aluminuma B Super I" manufactured by MP Biomedicals) is fired therein. A second layer was formed by further filling with 0.6 g of active alumina obtained by activating the mixture so as to have a height of 35 mm, and a second column was prepared. Then, in the first layer, silica gel was prepared. A second column in which the active alumina layer was erected on the upper side was connected to the lower end of the first column in which the layer was erected on the upper side to prepare an extraction column.

The whole amount of sample A and 0.8 mL of isooctane were added onto the first layer of the extraction column, and the mixture was allowed to stand for about 10 minutes. Then, 20 mL of n-hexane was supplied to the upper end of the first column at a rate of 2 mL / min and drained from the lower end of the second column. During this period, the temperature of the first layer of the first column was maintained at room temperature (25 ° C.). After the supply of n-hexane is completed, the first column and the second column are separated, and air is supplied to the inverted second column in the direction opposite to the passage direction of n-hexane to form the second column. The n-hexane remaining in was removed. At this time, the second column was heated and its temperature was maintained at 85 ° C.

Next, toluene was supplied to the second column maintained in the upside-down state in the direction opposite to the passage direction of n-hexane, and PCBs trapped in the second layer were extracted. At this time, the second column was heated to maintain the temperature of the second layer at 85 ° C. The toluene supply rate was set to 100 μL / min, and about 900 μL of the toluene solution discharged from the second column was collected as an extract of PCBs. It took about 0.7 hours from the addition of sample A and isooctane to the acquisition of this extract.

For the obtained extract, the recovery rate of PCBs was calculated. Here, an analytical sample is prepared by adding 50 μL of an internal standard substance solution for calculating the recovery rate (trade name “P48-RS-STK” of Wellington Laboratories) to the extract, and this analytical sample is used. Analysis is performed by the HRGC / LRMS method according to the method described in the "Temporary Manual for Investigation of Extrinsic Endocrine Disrupting Chemicals" presented by the Environment Agency in October 1998, and the PCB recovery rate is calculated by the method described in the manual. did.

The results are shown in FIG. In FIG. 6, the symbol (# 1 etc.) indicating the type of PCBs is an IUPAC number, and the indication such as “1Cl” means the chlorine number of PCBs. According to FIG. 6, it can be seen that all the PCBs, from the PCBs having a chlorine number of 1 to the PCBs having a chlorine number of 10, are recovered with a high recovery rate of more than 80%.

[Experimental Example II]
<Experimental Examples II-1 and II-2>
Work and extract in the same manner as in Experimental Example I except that the sample A was changed to the sample B and the standing time after the addition of the total amount of the sample B and 0.8 mL of isooctane was changed as shown in Table 1. Obtained liquid.

<Experimental Examples II-3, II-4>
A column having a height of 40 mm was prepared by filling a column having an inner diameter of 13 mm and a length of 70 mm with 3.8 g of silica gel sulfate (trade name "Lapiana Sulfate Silica" of Miura Co., Ltd.). The points used as this column and the first column, and the points where sample A was changed to sample B and the standing time after addition of the total amount of sample B and 0.8 mL of isooctane were changed as shown in Table 1. The same procedure as in Experimental Example I was carried out except for the above, and an extract was obtained.

<Evaluation of Experimental Example II>
For the extracts obtained in each experimental example, the recovery rate of PCBs was calculated by the same method as in experimental example I. The results are shown in Table 1.

According to Table 1, in Experimental Examples II-3 and II-4 using the first column consisting of only the silica gel sulfate layer as the first layer, the standing time after the addition of the total amount of sample B and 0.8 mL of isooctane was obtained. If the length is long, the recovery rate of PCBs having a chlorine number of 1 will be greatly reduced. However, Experimental Example II-1 using a first column in which the first layer is silica gel sulfate laminated on silica gel, It can be seen that in II-2, there is substantially no change in the recovery rate of PCBs having a chlorine number of 1 even if the standing time is long.

[Experimental Example III]
<Experimental Examples III-1, III-2, III-3>
The column prepared in Experimental Examples II-3 and II-4 (the first layer is composed of only a silica gel sulfate layer) was used as the first column, and the second column was the same as that used in Experimental Example I. The column is filled with metal oxide-containing aluminum oxide as shown in Table 2, and aluminum oxide (trade name "MP Aluminuma B Super I" manufactured by MP Biomedicals) is fired and activated on the column. The point that the second layer was formed by further filling the obtained 0.6 g of activated alumina to a height of 3.5 cm was used, and the sample A was changed to the sample C, and the sample C was changed. After adding 0.8 mL of isooctane and 0.8 mL of isooctane to the first layer, work in the same manner as in Experimental Example I except that the n-hexane was immediately started to be supplied to the first column to obtain an extract. rice field. It took about 0.8 hours from the addition of sample C and isooctane to the acquisition of this extract.

<Experimental Example III-4>
Experimental Examples III-1, III-2 and Experimental Examples III-1 and III-2, except that the second layer used only a layer composed of a layer filled with 0.7 g of metal oxide-containing aluminum oxide so as to have a height of 3.5 cm. The work was carried out in the same manner as in III-3 to obtain an extract. It took about 0.7 hours from the addition of sample C and isooctane to the acquisition of this extract.

<Evaluation of Experimental Example III>
For the extracts obtained in each experimental example, the recovery rates of PCBs having a chlorine number of 1 and 2 and PCBs having a chlorine number of 10 were calculated by the same method as in Experimental Example I. The results are shown in Table 2. According to Table 2, it can be seen that the recovery rate of PCBs having a low chlorine content is increased by arranging the activated alumina layer on the metal oxide-containing aluminum oxide layer.

[Experimental Example IV]
Except for the fact that sample A was changed to sample D and n-hexane was immediately started to be supplied to the first column after the addition of 0.5 mL of sample D and 0.8 mL of isooctane. The same operation was performed to obtain an extract.

For the obtained extract, the concentration of PCBs was measured and the recovery rate was calculated. Here, a sample for analysis was prepared by adding 50 μL of an internal standard substance solution for calculating the recovery rate (trade name “P48-RS-STK” of Wellington Laboratories) to the extract. Then, this sample for analysis was measured by the capillary column-gas chromatograph quadrupole mass spectrometry method according to the method described in the sediment survey method (II.6.4) of the Water and Air Environment Bureau of the Ministry of the Environment in August 2012. , The concentration of PCBs was measured, and the recovery rate of the standard substance in PCB was calculated. The results are shown in Table 3. The results shown in Table 3 were evaluated based on the average values of PCB concentrations and recovery rates obtained for each extract after performing the extraction preparation work three times.

For any PCB homologue with a chlorine number of 1 to 10, the quantitative value (concentration measurement value) is within ± 2SD (standard deviation) with respect to the certified value, and it is possible to measure the concentration with high reliability. Recognize. The reason why the recovery rate of PCBs having chlorine numbers of 9 and 10 is low is that some of these PCBs are decomposed by the action of alkali (potassium hydroxide) in the process of preparing sample D. ..

1 Extraction column 10 First column 14 First layer 15 Retention layer 16 Sulfuric acid silica gel layer 20 Second column 23 Second layer 25 First alumina layer 26 Second alumina layer

Claims (8)

A method for extracting polychlorinated biphenyls from a solution containing polychlorinated biphenyls.
To the holding layer of the first layer including a holding layer formed by using a material having liquid permeability, permeation of the solution, and inert to polychlorinated biphenyls, and a silica gel sulfate layer. Step 1 of adding the solution and
Step 2 of supplying an aliphatic hydrocarbon solvent from the holding layer side to the first layer to which the solution is added and passing the holding layer and the silica gel sulfate layer in this order .
The aliphatic hydrocarbon solvent that has passed through the first layer is supplied from the first alumina layer side to the second layer including the first alumina layer and the second alumina layer, and the first alumina layer and the first alumina layer are supplied . Step 3 of passing the two alumina layers in order, and
Step 4 of supplying and passing the extraction solvent of polychlorinated biphenyls to the second layer through which the aliphatic hydrocarbon solvent has passed.
Including step 5 of securing the extraction solvent that has passed through the second layer.
The second alumina layer contains aluminum oxide containing at least one metal oxide selected from the group consisting of nickel oxide and silver oxide.
In step 1 and step 2, the temperature of the first layer is set to less than 35 ° C.
Extraction method for polychlorinated biphenyls. The method for extracting polychlorinated biphenyls according to claim 1, wherein the retaining layer is formed using silica gel. The method for extracting polychlorinated biphenyls according to claim 1 or 2, wherein in step 4, the extraction solvent is supplied and passed through the second layer in a direction opposite to the passage direction of the aliphatic hydrocarbon solvent. .. The poly according to any one of claims 1 to 3, wherein the aliphatic hydrocarbon solvent remaining in the second layer is removed before supplying the extraction solvent to the second layer in step 4. Extraction method of biphenyl chlorides. The solution is a collection of polychlorinated biphenyls extracted from a material layer at the bottom of the aquatic zone or on the surface of land, food, biological samples, environmental water, wastewater, incineration ash, or a collection of gas-containing substances using a solvent. The method for extracting polychlorinated biphenyls according to any one of claims 1 to 4. A column for extracting polychlorinated biphenyls from a solution containing polychlorinated biphenyls.
Both ends filled with a holding layer formed of a material that has liquid permeability, is permeable to the solution , and is inert to polychlorinated biphenyls, and a first layer containing a silica gel sulfate layer. The first column with an opening in
A second column having openings at both ends filled with a second layer including a first alumina layer and a second alumina layer, which is detachably connected to the first column, is provided.
The first layer contains the holding layer and the silica gel sulfate in this order from one opening of the first column toward the other opening.
The second layer includes the first alumina layer and the second alumina layer in this order from one opening of the second column toward the other opening.
The second alumina layer contains aluminum oxide containing at least one metal oxide selected from the group consisting of nickel oxide and silver oxide.
In the second column, the end portion on the first alumina layer side is detachably connected to the end portion on the silica gel sulfate layer side of the first column.
Column for extracting polychlorinated biphenyls. The column for extracting polychlorinated biphenyls according to claim 6, wherein the holding layer is formed by using silica gel. The column for extracting polychlorinated biphenyls according to claim 6 or 7, wherein in the second column, the first alumina layer and the second alumina layer are filled so as to have the same volume.

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