JP2003344378A - Pretreating column and method for analyzing dioxins - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an effective method of speedily, simple, and inexpensively pretreating an analysis sample for the analysis of dioxins while maintaining a high recovery rate with satisfactory reproducibility, and to provide a pretreating column for analyzing dioxins for implementing the method. <P>SOLUTION: A diatomaceous earth column 10 having a silica gel layer 14, a sulfuric diatomaceous earth layer 16, and a polarity carrier layer 18 is connected to an active carbon column 20. By making a sample to be analyzed and a solvent flow down through the diatomaceous earth column 10 and making impurities adsorbed in the diatomaceous earth column 10, the dioxins are eluted into the active carbon column 20. The active carbon column 20 is inverted to make the solvent flow down to elute the dioxins. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rapid purification method for dioxins analysis. In particular, the present invention relates to a pretreatment method for an analytical sample used for dioxins analysis.

[0002]

2. Description of the Related Art Dioxins are compounds that belong to highly toxic chlorinated aromatic hydrocarbons, and as a typical compound, polychlorodibenzo-p-dioxin (PCD
D), polychlorodibenzofuran (PCDF) and coplanar PCB.

Qualitative / quantitative analysis of dioxins contained in the ambient atmosphere is usually carried out by a gas chromatograph / mass spectrometer (GC / MS). At this time, the dioxins contained in the analytical sample collected from the environmental atmosphere are in very small amounts (ppb to ppq level), and there is a large excess of impurities that affect the analytical value. It is necessary to perform pretreatment to reduce the content of impurities. In addition, there are many isomers in dioxins, which requires extraction and purification steps of dioxins,
There is a problem that these steps take time.

For example, as a method for analyzing dioxins contained in an environmental atmosphere, there is a "measuring method for dioxins and coplanar PCB in exhaust gas (JIS K0311)" (1999) in which sulfuric acid treatment and an activated carbon column are combined. .

The pretreatment of the sample to be analyzed in the JIS method (K0311: 1999) is as shown in FIG. 1, after adding an internal standard substance to the collected sample (cleanup spike), filter paper,
Extraction for each form of resin, absorption liquid, etc., and after combining these extraction liquids, if necessary, fractionate and perform sulfuric acid treatment silica gel column chromatograph operation or multi-layer silica gel chromatography operation sample for dioxins measurement And a sample for coplanar PCB measurement, further, an alumina column chromatographic operation was performed on each sample, and further purified by high-performance liquid chromatography, etc., if necessary, and an internal standard substance was added to the obtained sample ( Syringe spike), followed by gas chromatograph mass spectrometry. Since the two-step purification of the silica gel chromatograph and the alumina column chromatograph is required as described above, the pretreatment can be performed with high accuracy, but the pretreatment operation is complicated and time-consuming, and it is expensive and complicated high-performance liquid chromatography. There is the problem of requiring a graph device. In addition, because analysis work requires skill, there are variations in results among workers, purification operations require more than a week, and large amounts of reagents and solvents are required, which is expensive and reagent storage There is a problem that a large work area is required for the work and that an analysis using a high-performance liquid chromatograph does not allow an accurate analysis due to cross-contamination when simultaneously analyzing a sample having a large concentration difference.

[0006] Therefore, the method of Matsumura et al. (Hyogo Prefectural Institute of Environmental Pollution), which is a modification of the JIS method aimed at shortening the time and reducing the amount of solvent used (8th Environmental Chemistry Conference, 202 -203 (1999)) has been proposed.

The method of Matsumura et al. Is based on a multilayer silica gel column commonly used in the art and a carbon column "Carboxen 1000 Reversing Tube (Si) for coplanar PCB fractionation.
gma-Aldrich) ”(hereinafter abbreviated as“ carbon column ”)
And are combined. Specifically, a solvent reservoir is connected to the upstream side of the multilayer silica gel column, a carbon column is connected to the downstream side of the multilayer silica gel column, and 10 to 20 mL of hexane is flown into the solvent reservoir for conditioning, and then a sample is loaded, Hexane 50 mL flow rate 3-4 mL / m
Pour in to collect the eluate on the carbon column (fraction 1). Next, the multilayer silica gel column was removed, the solvent reservoir was directly connected to the carbon column, and dichloromethane / n-hexane = 20/80 was flown into the solvent reservoir at a flow rate of 3 to 4 mL / mi.
Flow 60 mL of n and collect the eluate on the carbon column (Fraction 2). Next, the carbon column was removed from the solvent reservoir, the carbon column was again attached to the solvent reservoir in the opposite direction, and 80 to 100 mL of toluene was flowed at a flow rate of 1 to 2 mL / min to collect the eluate in the solvent reservoir ( Fraction 3). Separate the obtained eluate by 10 mL and concentrate to 1 mL, then add H
This is a method of quantifying by RGC / HRMS.

[0008] However, the effect of sulfuric acid treatment on the actual sample and the recovery rate with respect to the amount added are unknown. From the graph in the summary, elution with 80 mL of toluene (room temperature) continued to elute dioxin, and the elution occurred. It can be seen that it is insufficient, and further, the coplanar PCB remains in the column, which makes it extremely difficult to manage the column thereafter. Further, from the viewpoint of preventing secondary pollution of dioxins, it is not preferable that elution of dioxins continues in a gradual manner. The method of Matsumura et al. Is not so practical as a simple alternative pretreatment method of JIS method. That is, the method of Matsumura et al. Has problems such as insufficient efficiency of sulfuric acid treatment, high running cost, and insufficient recovery rate of dioxins.

The activated carbon column used for pretreatment of dioxins analysis has a high purification effect due to its strong retention of dioxins, but has a low recovery rate.
It has a drawback of high elution of impurities. Therefore, conventionally, depending on the type of activated carbon, an efficient and complicated high-performance liquid chromatograph was constructed (Hypercarb: Thermo Hypers
When using il-Keystone), add 1 part of toluene heated to 70 ℃.
Flow 00 mL (when using Envicarb C: Sigma-Aldrich) or compromise about 50% recovery (Carboxen1000: S
(When using igma-Aldrich), only coping therapy is provided.

Although column chromatography technology is widely used as a pretreatment for dioxins analysis, it is well known to those skilled in the art that, in column chromatography technology, a carrier suitable for the substance to be analyzed is selected. is important. However, in the case of dioxins, since various isomers coexist, a carrier suitable for rapid and simple pretreatment has not been established yet.

[0011]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the above-mentioned drawbacks of the prior art and to provide a practical pretreatment method for dioxin analysis as a simple alternative pretreatment method of JIS method. . That is, it is an object of the present invention to provide an effective pretreatment method for an analyte sample to be used for dioxins analysis, while maintaining high recovery rate quickly, simply and inexpensively with good reproducibility.

Another object of the present invention is to carry out an effective pretreatment method for the sample to be analyzed for dioxins, while maintaining high recovery rate quickly, simply and inexpensively, with good reproducibility. To provide a pretreatment column for the analysis of dioxins.

[0013]

As a result of intensive research to solve the above problems, the present inventors have found that a diatomaceous earth column containing a sulfated diatomaceous earth layer formed by treating diatomaceous earth with a predetermined amount of sulfuric acid,
It was found that by introducing a sample for analysis containing dioxin, impurities can be sufficiently adsorbed and retained in the diatomaceous earth sulfate and removed from the sample for analysis containing dioxin. That is, according to the present invention, a dioxin analysis pretreatment column including a diatomaceous earth column containing a sulfated diatomaceous earth layer obtained by treating diatomaceous earth with sulfuric acid and a dioxin-containing analyte sample using the dioxin analysis pretreatment column A pretreatment method is provided.

The diatomaceous earth column used in the present invention is a column containing a sulfated diatomaceous earth layer obtained by treating with sulfuric acid (FIG. 2).
This diatomaceous earth column can be easily manufactured by simply filling the column with commercially available diatomaceous earth for column packing and injecting sulfuric acid from above the diatomaceous earth (FIG. 3). The diatomaceous earth which can be used in the sulfated diatomaceous earth layer of the present invention preferably has a particle size of 90% or more at a 60 mesh collection rate and 95% or more at a 100 mesh collection rate. The loss on ignition is less than 1%. The packing density of diatomaceous earth in the column is preferably about 0.3 g / mL. The filling amount of diatomaceous earth varies depending on the type and amount of the sample to be analyzed. For example, for a 30 g bottom sample, about 6.3 g diatomaceous earth can be used.

The sulfuric acid retained in the diatomaceous earth is preferably that specified in JIS K8951 or that of equivalent quality. By retaining the sulfuric acid in the diatomaceous earth, it is possible to improve the sulfuric acid treatment efficiency of the dioxin-containing sample to be analyzed. Diatomaceous earth has many small pores of biological origin,
Although there are large gaps between the carriers, the sulfuric acid is retained more in the smaller pores, which have a higher space packing density. Therefore, it is considered that the ratio of the small pores to the large gaps of the diatomaceous earth becomes larger after the addition of the sulfuric acid than in the case where the sulfuric acid is not added. Furthermore, after adding sulfuric acid,
The sulfuric acid is retained in the small pores and the pore diameter is smaller, so that the solvent flows in a larger amount in the relatively large gap. After the sample to be analyzed is added to the diatomaceous earth column, the sample is allowed to stand for a predetermined time (preferably about 15 minutes) so that the sample to be analyzed permeates deep inside the small pores of the diatomaceous earth to remove the sulfuric acid retained in the diatomaceous earth. The contact of
Improves sulfuric acid treatment efficiency. However, if the treatment efficiency is too high, depending on the sample, contaminants may not be retained by the diatomaceous earth and may leak into the extract, which may change the extract to a mucus, and after the diatomaceous earth column treatment, A filtration operation with a silica gel column may be necessary. Such an additional operation is not desirable for rapid and simple pretreatment of dioxins analysis sample. Therefore,
In order to omit the silica gel column treatment after the diatomaceous earth column treatment, it is desirable to maintain the treatment efficiency of the diatomaceous earth sulfate layer in an optimum range in which impurities are retained in the sulfate diatomaceous earth layer for a predetermined time and do not leak into the extract. As a result of the experiments described below to identify the optimum range, the present inventors found that the diatomaceous earth column used in the present invention has a column capacity of about 70%.
It has been found that it is preferable to contain a diatomaceous earth sulfate layer formed by holding up to 90% by volume of sulfuric acid, and particularly preferable that a diatomaceous earth layer formed by holding about 80% by volume of sulfuric acid in the column holding volume. Here, the “column holding capacity” means the maximum amount of pure water added from the upper part of the column that can be held inside without leaking from the lower part of the column. In addition, the amount of sulfuric acid added per 1 g of diatomaceous earth constituting the sulfated diatomaceous earth layer is
About 0.7-1.8 mL, especially about 1.42 mL is preferred.

The diatomaceous earth column used in the present invention preferably includes a silica gel layer disposed upstream of the diatomaceous earth sulfate layer. The silica gel constituting the silica gel layer is silica gel for column chromatography (63 to 212 μm).
m) simple substance or silver nitrate (10 mass%) silica gel (JIS K8550 for 100 g of silica gel for column chromatography)
28 ml of silver nitrate solution (400 g / l) prepared with silver nitrate specified in
And the like) and the like can be used. Furthermore, in addition to these silica gels, anhydrous sodium sulfate may be spread on the silica gel layer.

By disposing the silica gel layer on the upstream side of the sulfated diatomaceous earth layer, when the sample to be analyzed containing dioxin is introduced into the diatomaceous earth column and pretreatment is carried out, the sample to be analyzed containing dioxin is introduced to the sulfated diatomaceous earth layer. By allowing the silica gel layer to pass through before the reaction, impurities in the dioxins-containing analyte sample can be adsorbed and retained on the silica gel layer and removed from the dioxins-containing analyte sample. As described above, before passing through the diatomaceous earth sulfate layer, the impurities in the dioxins-containing analyte sample are adsorbed on the silica gel layer and removed in advance, thereby reducing the contaminant retention capacity, that is, the load amount by the diatomaceous earth sulfate layer. be able to. However, if the amount of silica gel packed upstream of the diatomaceous earth sulfate layer is too large, the time required for the dioxins-containing sample to be analyzed to come into contact with the downstream diatomaceous earth layer becomes longer. This is because, when compared with a fixed treatment time, the greater the amount of silica gel packed, the shorter the contact time between the dioxin-containing analyte sample and the sulfated diatomaceous earth layer, resulting in a reduction in the treatment efficiency of the sulfated diatomaceous earth layer. Means that. Therefore, the packing amount of silica gel disposed on the upstream side of the diatomaceous earth sulfate layer can efficiently reduce the contaminant load of the dioxin-containing analyte sample passing through the diatomaceous earth sulfate layer, and the dioxin-containing analyte It is desirable that the contact time between the sample and the diatomaceous earth sulfate layer be sufficiently maintained. As a result of performing experiments described below to identify the optimum range, the inventors have found that in the diatomaceous earth column used in the present invention, the packing amount of the silica gel layer arranged on the upstream side of the sulfated diatomaceous earth layer is Is preferably about 30 to 80% by weight, particularly about 35 to 70% by weight. Column retention capacity 10
It has been found that when the diatomaceous earth column of mL is packed with about 7 g of diatomaceous earth, the maximum amount is preferably about 4 g, and particularly about 2 g is preferable.

Further, as described above, by disposing the silica gel layer on the upstream side of the diatomaceous earth sulfate layer, it is possible to control the flow rate when the analytical sample retained in the diatomaceous earth sulfate layer is eluted with the solvent. There are also advantages. As mentioned above, the sulfuric acid added to the diatomaceous earth is retained in a larger amount by the smaller pores having a higher space filling density. However, if the flow rate of the solvent at the time of elution is high, the elution solvent will not penetrate deep into the small holes, and the recovery rate will decrease. Therefore, by disposing a silica gel layer on the upstream side of the diatomaceous earth sulfate layer, the solvent flow rate is slowed down, and the solvent is sufficiently diffused in the diatomaceous earth sulfate layer to suppress channeling, thereby improving the recovery rate. it can. Here, channeling means that when the amount of sulfuric acid added to the diatomaceous earth increases, the sulfuric acid coating on the diatomaceous earth becomes non-uniform, and a wide solvent flow path occurs in the thin portion of the sulfuric acid coating, causing a larger amount of solvent to flow. Say. By this channeling, the solvent easily flows into the thin portion of the sulfuric acid coating, so that the contact efficiency with the dioxins in the analytical sample retained in the sulfuric acid-treated diatomaceous earth decreases, and the recovery rate of dioxins decreases. . Therefore, suppressing the channeling also prevents a decrease in the recovery rate of dioxins. Although it is possible for an analyst to control the flow rate by pipetting from the viewpoint of flow rate control only, from the viewpoint of eliminating variations among operators and improving reproducibility, the silica gel layer can be arranged. It is more preferable to control the flow rate by setting.

Further, the diatomaceous earth column of the pretreatment column for dioxins analysis of the present invention preferably comprises a polar carrier layer disposed on the downstream side of the sulfated diatomaceous earth layer. Since the polar carrier layer can retain contaminants such as polycyclic aromatic organic compounds, the purification efficiency can be further improved. Examples of the polar carrier layer that can be used in the present invention include polar carrier layers filled with diatomaceous earth, silica gel, alumina, magnesium silicate and the like. In particular, from the viewpoint of improving the work efficiency of filling the column
It is preferable to use diatomaceous earth. Further, by using alkaline diatomaceous earth, there is also an advantage that a highly efficient post-treatment can be performed without performing a necessary alkali treatment as a post-treatment for sulfuric acid treatment according to the JIS method. The ratio of the polar carrier layer and the sulfated diatomaceous earth layer packed in the diatomaceous earth column is preferably 1: 9 to 3: 7 as the polar carrier layer: sulfated diatomaceous earth layer, and particularly preferably 2: 8.

The diatomaceous earth column of the present invention is, for example, a column having a column holding capacity of 10 ml filled with 7 g of diatomaceous earth, and sulfuric acid is injected onto the diatomaceous earth and left for about 15 minutes to allow the diatomaceous earth to retain sulfuric acid. It can be prepared by forming a polar carrier layer at the bottom and a diatomaceous earth layer on the polar carrier layer, and then filling silica gel on the diatomaceous earth to form a silica gel layer. Alternatively, instead of packing the diatomaceous earth into the column, a commercially available diatomaceous earth packed column (for example, trade name: CE-1010 (10 mL holding volume); CE-1005 (5 mL
Retaining capacity), both manufactured by Varian) can also be used. By using such a commercially available diatomaceous earth-filled column, it is possible to omit the column packing work which is complicated and varies among operators, and it is possible to improve reproducibility.

The diatomaceous earth column of the present invention enhances the efficiency of sulfuric acid treatment of a dioxins-containing sample to be analyzed containing impurities to improve the purification efficiency, and the filtration operation using a silica gel column can be omitted, and the diatomaceous earth column can be quickly (for example, 20%). Minute), with high reproducibility and high recovery, it is possible to pretreat the sample to be analyzed containing dioxins.

Further, the pretreatment column for dioxins analysis of the present invention preferably further comprises an activated carbon column which is removable from the diatomaceous earth column, particularly an activated carbon column in the form of a reverse cartridge column, on the downstream side of the diatomaceous earth column. .

Since activated carbon has a property of specifically adsorbing molecules having a flat structure such as dioxins, it is possible to separate dioxins from other organic compounds. However, if the dioxin retention capacity of the activated carbon is too strong, it becomes difficult to elute and recover the dioxin retained on the activated carbon in a later elution step,
On the contrary, if the activated carbon has too weak a holding power for dioxins, a large amount of dioxins will flow out. Therefore, the activated carbon column used as the pretreatment column for dioxins analysis of the present invention has characteristics such as excellent separability between dioxins and contaminants, high elution recovery of dioxins, and little elution of contaminants. Is preferred. Such an activated carbon column is particularly preferably an activated carbon column packed with activated carbon having a pore size that does not match the molecular size of various isomers of dioxins. Most of the adsorption of activated carbon occurs between the two graphite layers of the micropore, and the oxygen complex (ox
ygen complex) is also thought to affect adsorption (“Suzuki, M. 1990. Adsorption Engineering, Elsev
ier, ISBN 0-444-98802-5 ”). That is, due to the interaction between the planar structure of graphite that constitutes activated carbon and the planar structures of dioxins and coplanar PCB, and the polarity of the oxygen complex on the activated carbon surface,
It is thought that selective adsorption occurs. When the pore size of activated carbon and the molecular size of dioxins are close to each other,
That is, in the micropore, since the dioxin is sandwiched between the two graphite layers, the interaction becomes large, and the dioxin is adsorbed to the activated carbon very strongly. Also,
Since the micropores are located at the innermost part of the pores of the activated carbon in terms of the three-dimensional structure, the penetration and diffusion of the solvent are poor. Therefore, once dioxins are adsorbed on the micropores,
Elution with an organic solvent becomes very difficult. Therefore, the present inventors eliminated the influence of micropores that adsorb anything,
It has been found that the interaction with one graphite layer can selectively adsorb dioxins without adsorbing contaminants and improve the recovery rate of dioxins. In particular, it has been found that in mesopores having a size several times to several tens of times the molecular size of dioxins, the spacing between the graphite layers is appropriately wide, and adsorption / desorption is performed smoothly. Based on these findings, the activated carbon column that can be used in the present invention has a pore size of
Substantially free of micropores smaller than 2 nm, pore size 2 ~
An activated carbon column containing 0.1 mL / g or more of 50 nm mesopores can be preferably mentioned. In particular, an activated carbon column having a particle size of 60/80 mesh or 177 to 250 μm of activated carbon, preferably graphite carbon, having a density of 0.5 g / mL or more and a surface area of about 75 m ² / g, can be preferably mentioned. . Thus, by eliminating the effect of micropores that very strongly adsorb dioxins, by selectively adsorbing dioxins to mesopores in the activated carbon column, it becomes easier to elute from the activated carbon column in the next elution step, It is possible to increase the recovery rate of dioxins and obtain sharp fractionated peaks. Examples of such activated carbon columns include "Carboxen 1016" and "Carboxen
A commercially available activated carbon cartridge column such as "1017" (manufactured and sold by Sigma-Aldrich) can be used. When such a commercially available activated carbon cartridge is used, there is an advantage that the column filling work which is complicated and causes variations among workers can be omitted, and reproducibility can be improved.

The activated carbon column used as the pretreatment column for dioxins analysis of the present invention is preferably in the form of a reverse cartridge which can be attached to and detached from the diatomaceous earth column. The reverse type cartridge is a cartridge capable of reversing the flow direction of the fluid. In the present invention, the reverse type cartridge is first attached to the diatomaceous earth column, and the eluate from the diatomaceous earth column is introduced into the upper inlet (diatomaceous earth column eluate flow). It is received from the inlet) and is retained by the activated carbon packed in the activated carbon column. Next, remove the activated carbon column cartridge from the diatomaceous earth column, turn it upside down, introduce the eluent from the upper inlet (activated carbon column extraction solvent inlet), and dioxins retained on the activated carbon to the lower outlet. (In the first step, it can be eluted from the diatomaceous earth column eluate inlet port). By using such a detachable cartridge form, it becomes easy to remove the dioxin adsorbed and retained in the activated carbon column after adsorbing and retaining the dioxin on the activated carbon column. . Also, by adopting a reverse type cartridge, the inflow route of dioxins eluting from the diatomaceous earth column becomes the same as the outflow route of dioxins eluting from the activated carbon column, so it is eluted from the diatomaceous earth column to the activated carbon column. At this time, it becomes possible to sufficiently elute the dioxins adsorbed and held in the middle of the activated carbon column, and the recovery rate of dioxins can be increased. Furthermore, the reverse type cartridge is simple in design and manufacturing since it is sufficient to provide one liquid inflow / outflow path.

As described above, according to the pretreatment column for dioxins analysis of the present invention, the sample to be analyzed used for the analysis of dioxins can be rapidly, simply and inexpensively, with good reproducibility and maintaining a high recovery rate. An effective pretreatment method can be implemented. Compared with the conventional JIS method, this is
Regardless of the skill of the analyst, it enables measurement with little variation, the purification operation can be shortened from 2 days to 2 hours, and the use of reagents for extraction, purification and elution The advantages are that the amount is reduced, the management is easy, the expensive and complicated high-performance liquid chromatogram is not required, and the risk of cross-contamination is reduced.

Further, according to the present invention, dioxins comprising introducing a dioxins-containing sample to be analyzed into a pretreatment column for dioxins analysis containing a diatomaceous earth column containing a sulfated diatomaceous earth layer holding sulfuric acid. A method for pretreating a contained analyte is provided (FIG. 4). In particular, a silica gel layer, a diatomaceous earth sulfate layer obtained by retaining sulfuric acid in diatomaceous earth,
A polar carrier layer that adsorbs organic matter, and a pore size of 2 to 50 n, which does not substantially include micropores having a pore size of less than 2 nm.
It is preferable to remove impurities from the dioxin-containing sample to be analyzed by sequentially introducing m mesopores into the activated carbon layer containing 0.1 mL / g or more.

In the method of the present invention, the step of removing obstacles by sulfuric acid treatment, which has been carried out in the silica gel column chromatographic operation specified in JIS K0311 shown in FIG. The diatomaceous earth column is used as a pretreatment column for dioxins analysis, omitting the alumina column chromatograph operation specified in JIS K0311, and the high-performance liquid chromatographic operation is performed by the activated carbon column of the pretreatment column for dioxins analysis of the present invention described above. It can be carried out in the same manner as the pretreatment operation for the analysis of dioxins specified in JIS K0311, except that it is carried out in.

In order to explain the pretreatment method of the present invention, first, the pretreatment method defined in JIS K0311 will be outlined. J
IS K0311 specifies the following procedures for silica gel column chromatograph operations. The extract extracted from the sample is collected, concentrated, and the toluene is removed by a nitrogen stream. Wash with hexane, add sulfuric acid, shake gently, let stand, and remove the sulfuric acid layer. This operation is repeated until the sulfuric acid layer becomes lightly colored. The hexane layer is washed with hexane washing water, repeatedly washed until the washing liquid becomes almost neutral, dehydrated with sodium sulfate, and concentrated.
Quartz glass wool is packed in the bottom of a column chromatograph tube (inner diameter 10 mm, length 300 mm), the inside of the tube is washed with hexane, and hexane is left up to the top of the quartz glass wool. Weigh 3 g of silica gel into a beaker containing hexane, gently stir with a glass rod to remove air bubbles, and fill the column chromatograph tube. Hexane is allowed to flow down to stabilize the silica gel layer, sodium sulfate is placed on it, and the sodium sulfate adhering to the tube wall is washed off with hexane. After allowing hexane to flow down onto the silica gel, lower the liquid surface to the upper surface of sodium sulfate, gently transfer the solution prepared in to the column, wash with hexane several times, lower the liquid surface to the sodium sulfate surface, and add hexane dropwise. . Concentrate the eluate and use it as the sample solution for alumina column chromatography.

Alternatively, the following procedure is defined as the multilayer silica gel column chromatography method. The bottom of a column chromatograph tube (15 mm inside diameter, 300 mm length) is packed with quartz glass wool, and 0.9 g of silica gel, 3 g of potassium hydroxide (2 mass%) silica gel, 0.9 g of silica gel, 4.5 g of sulfuric acid (44 mass%) silica gel, sulfuric acid ( 22mass%) silica gel 6g, silica gel 0.9g, silver nitrate (10mass%) silica gel 3
g and 6 g of sodium sulfate are sequentially charged. After allowing hexane to flow down, the liquid surface is lowered to the upper surface of sodium sulfate. The extract is separated and concentrated, then toluene is removed by a nitrogen stream, and the mixture is gently poured into the column to lower the liquid level to the top of the column. Wash the extract container with hexane, and put the washing liquid while washing the inner wall of the column. Repeat this operation 2-3 times. Add hexane dropwise. Concentrate the eluate and use it as the sample solution for alumina column chromatography. When there is a lot of coloring in the filling part, the operations from to are repeated.

Next, the alumina column chromatographic operation specified in JIS K0311 will be outlined. Quartz glass wool is packed in the bottom of a column chromatograph tube (inner diameter 10 mm, length 300 mm), the inside of the tube is washed with hexane, and hexane is left up to the top of the quartz glass wool. Weigh 10 g of alumina into a beaker containing hexane, gently stir with a glass rod to remove air bubbles, and fill a column chromatograph tube. After allowing hexane to flow down and stabilizing the alumina layer, sodium sulfate is placed on it and the sodium sulfate adhering to the tube wall is washed off with hexane. After allowing hexane to flow down, the liquid surface is lowered to the upper surface of sodium sulfate. Gently transfer the sample solution prepared by silica gel column chromatograph operation or multi-layer silica gel column chromatograph operation, wash it with hexane, lower the liquid surface to sodium sulfate, and then flow it with a hexane solution containing the next chloromethane (2 vol%). To obtain the first fraction. Further, a hexane solution containing dichloromethane (50 vol%) is flowed to obtain a second fraction. The second fraction was concentrated, and the solvent was removed by volatilization with a nitrogen stream, and the internal standard substance for syringe spike was added to the same concentration as the standard solution for preparing the calibration curve, nonane was added, and the nitrogen stream was added again. The sample with a constant liquid volume is used as a measurement sample for dioxins.

As described above, the pretreatment method defined in JIS K0311 requires silica gel chromatographic operation or multilayer silica gel chromatographic operation and alumina column chromatographic operation. An object of the present invention is to provide a pretreatment method in which this two-step chromatographic operation is extremely easily performed in one step.

The pretreatment method of the present invention comprises a diatomaceous earth column (column holding capacity 10 mL) in which a polar carrier layer, a diatomaceous earth sulfate layer and a silica gel layer are packed in this order from the bottom of the column and an activated carbon column which does not substantially contain micropores. In the pretreatment column for dioxins analysis of the present invention, which is linked with
An analyte sample containing dioxins is introduced. Specifically, as shown in FIG. 4, n-hexane 10 was added from the top of the diatomaceous earth column with the diatomaceous earth column and the activated carbon column being connected.
After introducing mL and washing with n-hexane, 1 mL of the dioxin-containing analyte sample was added to the diatomaceous earth column,
Next, add 5 mL of a dichloromethane washing solution and leave it for 15 minutes. Next, add 10 mL of n-hexane to the diatomaceous earth column, and add a mixture of n-hexane and dichloromethane (2: 1) 30
Pour mL. Thus, the contaminants in the sample to be analyzed are retained in the diatomaceous earth column for separation, and dioxins are eluted in the activated carbon column. In the activated carbon column, dioxins are adsorbed and retained by the activated carbon, and the impurities contained in the sample to be analyzed flow down and are discharged from the activated carbon column. Next, remove the activated carbon column from the diatomaceous earth column, turn it upside down, and attach it to the solvent supply station (the lure port adapter of the secondary conduit) of the automatic liquid transfer system described below, supply the eluent (warm toluene), and remove it from the activated carbon column. The fraction containing dioxins (analyte sample to be analyzed for dioxins) is eluted. The temperature of hot toluene is 40
To 55 ° C, preferably 45 to 50 ° C.

The solvent which can be used in the pretreatment method of the sample for analysis containing dioxins of the present invention is
A commonly used solvent can be used. For example, n-
Hexane, n-heptane, n-octane, n-nonane and n-decane, dichloromethane, and mixtures thereof can be preferably mentioned. As the solvent used for elution from the activated carbon column, alkylbenzene: toluene, xylene and a mixture thereof can be preferably mentioned, and warm toluene at about 40 to 55 ° C is particularly preferable. Specifically, in order to adjust the solvent composition, it is preferable to first saturate the pretreatment column with hexane. Then, in order to improve the washing efficiency and the elution efficiency, it is preferable to flow down a highly polar solvent such as a hexane-dichloromethane mixed solution (2: 1). The mixing ratio of hexane and dichloromethane varies depending on the purpose of analysis, but is preferably in the range of about 3: 1 to 1: 1. Then, during elution to the activated carbon column,
It is preferable to let hexane flow down. Finally, for elution of dioxins from the activated carbon column, it is preferable to use toluene, particularly warm toluene at about 50 ° C, as an eluent.

According to the pretreatment method of the present invention, the silica gel layer removes a part of the impurities to reduce the load on the downstream diatomaceous earth sulfate layer, so that the efficiency of the sulfuric acid treatment is improved. Further, by introducing the sulfuric acid-treated analyte sample as it is into the polar carrier layer and introducing it, impurities such as polycyclic aromatic organic compounds can be adsorbed and removed, so that the purification efficiency can be further improved. Further, since the pore size is substantially free of micropores less than 2 nm and the activated carbon column containing 0.1 mL / g or more of mesopores having a pore size of 2 to 50 nm is used, dioxins are selectively adsorbed and separated from contaminants. Since the adsorbed dioxins can be easily eluted, the recovery efficiency can be improved.
In particular, in the pretreatment method performed using the dioxin-containing analyte pretreatment column of the present invention, all the steps can be performed by one pretreatment column, so the pretreatment work becomes very easy, The pretreatment time can be greatly shortened.

Further, according to the present invention, the solvent bath provided with the flow rate control means for controlling the flow rate of the solvent, the constant temperature bath for heating the solvent, and the solvent heated in the constant temperature bath are supplied to the object to be supplied. A solvent supply station, a main conduit provided between the solvent tank and the constant temperature tank for flowing a solvent, connected to the main conduit on the outside of the upstream side of the constant temperature tank, and on the outside of the downstream side of the constant temperature tank. An automatic liquid delivery device is provided that comprises one or more secondary conduits of corrosion resistant, pressure resistant, heat resistant material connected to a solvent supply station (FIG. 5). This device can be advantageously used in the elution step from the activated carbon column in the pretreatment method for the dioxins-containing analyte sample. That is, the present apparatus can be used to quantitatively and safely supply an eluent used when eluting dioxins adsorbed and held on an activated carbon column. Hereinafter, a specific description will be given with reference to FIG.

As shown in FIG. 5, the automatic liquid feeding system 100 includes a solvent tank 110 in which a solvent bottle 112 and a liquid feeding pump 114 are incorporated, a main conduit 130 for feeding a solvent from the solvent tank 110 to a constant temperature tank 120, A constant temperature tank 120 for heating the solvent, a sub-conduit 140 for feeding the solvent from the main conduit 130 to each activated carbon column 20 inside the constant temperature tank 120, a splitter 132 and a splitter 132 for separating the solvent from the main conduit 130 to the sub-conduit 140. It includes a stopcock 134 provided on the downstream side for opening and closing according to the number of activated carbon columns requiring a solvent, and a luer port adapter 150 for injecting the solvent from each auxiliary conduit 140 into each activated carbon column 20. The main conduit 130, the splitter 132, and the stopcock 132 are positioned outside the upstream side of the constant temperature tank 120, and are connected to the sub conduits 140 outside the constant temperature tank 120. Inside the constant temperature bath 120, the auxiliary conduit is made seamless so as to prevent leakage and to safely heat a flammable solvent such as toluene. The main conduit 130 from the solvent bath 110 to the inlet of the constant temperature bath 120 may be made of polyetheretherketone (PEEK), but the constant temperature bath
The secondary conduit 140 from the 120 outlet to the luer adapter 150 is SUS
Must be made. Being made of PEEK, the constant temperature bath 12
The solvent heated at 0 is cooled, which is not preferable. SUS
When manufactured, the heat can be transferred to the solvent from the sub-conduit 140 itself heated inside the thermostat 120 and the thermostat 120
Activated carbon column 20 by moderate air cooling of the secondary conduit 140 outside
There is not much heat applied to the plastic part of.
For example, if the length of the SUS conduit outside the thermostat 120 is 15 cm, and the thermostat 120 is set to 70 ° C, the temperature of the solvent (toluene is preferable here) sent in the laboratory atmosphere is
It will be about 45 ℃.

By supplying the eluent by using such an automatic liquid feeding system, the elution can be performed without causing the problem of the eluent leakage due to the expansion of the connector portion which occurs when heating the entire column which is the conventional mode. By heating only the liquid, the dioxins retained on the activated carbon column can be eluted with a small amount of solvent. This is
This is particularly advantageous because it makes handling of toluene very safe, such as when it is necessary to heat and use toluene which is a flammable solvent when eluting from a column of activated carbon such as dioxins. In addition, before starting the pretreatment work, by using this automatic liquid feeding system, the activated carbon column used in the pretreatment column of the present invention is washed with a preheated solvent (preferably toluene heated to 50 ° C.) to obtain dioxin. It is also possible to achieve the lower limit of quantitation of 0.2 pg or less, which complies with the Act on Special Measures for Class II That is, since such an automatic liquid feeding system can safely supply a desired amount of solvent to an activated carbon column at a desired temperature, the solvent temperature is made uniform, the solvent supply amount is automatically controlled, and the solvent supply speed is automatically controlled. Etc. can be achieved, the solvent can be handled safely, variation in pretreatment efficiency among workers can be avoided, and work time can be shortened. Further, by using this automatic liquid feeding system, the background noise of the activated carbon column can be reduced by washing the activated carbon column with a heated solvent (toluene) before use. The automatic liquid feeding system can be used in each step of the pretreatment for dioxins analysis. For example, if a diatomaceous earth column is attached to the solvent supply station, the temperature and the amount of the solvent introduced into the diatomaceous earth column can be automatically controlled in the steps of developing, concentrating, washing, and eluting the sample with the solvent. . Further, this automatic liquid feeding system can be applied to the pretreatment of various trace analysis samples in addition to the dioxin analysis pretreatment method.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in more detail with reference to the accompanying drawings, but the present invention is not limited thereto.

FIG. 2 is a sectional view schematically showing the structure of a pretreatment column for dioxins analysis of the present invention (hereinafter abbreviated as "pretreatment column"). The pretreatment column 1 includes a diatomaceous earth column 10 including a sulfated diatomaceous earth layer formed by sulfuric acid treatment, and an activated carbon column 20 that is detachably connected to the downstream side of the diatomaceous earth column 10. Diatomaceous earth column 10 has an open top 10a
And a fluid communication port 12 for connection that can be detached from the activated carbon column 20.
And a lower end portion 10b having.
In the diatomaceous earth column 10, the silica gel layer 14, the sulfate diatomaceous earth layer 16 and the polar carrier layer 18 are arranged from the upstream side, that is, the open upper end 10a side.
Is filled.

The method for preparing the pretreatment column of the present invention will be described. Here, a commercially available diatomaceous earth column (CE-1010: column volume 10 mL; diatomaceous earth filling amount 7 g) was used.
A case where a commercially available activated carbon column (Carboxen 1016) is used as an activated carbon column will be described.

As shown in FIG. 3, first, the diatomaceous earth column 10
And the activated carbon column 20 are connected. Next, diatomaceous earth column 10
Add 8 mL of sulfuric acid to the mixture and leave it for 15 minutes to remove the diatomite sulfate layer 16
To form. At this time, since sulfuric acid does not reach the lowermost part of the diatomaceous earth layer packed in the diatomaceous earth column 10, the lower part of the diatomaceous earth layer in the diatomaceous earth column 10 remains untreated with sulfuric acid.
The untreated diatomaceous earth layer remaining without reaching this sulfuric acid is used as the polar carrier layer 18. Next, 2 g of silica gel is laid over the diatomaceous earth sulfate layer 16 to form the silica gel layer 14.

Next, the pretreatment method of the sample to be analyzed containing dioxins using the pretreatment column of the present invention will be explained.
As shown in FIG. 4, a diatomaceous earth column 10 (column holding capacity 10 mL) and an activated carbon column (Carboxen 1016) 20 in which a polar carrier layer 18, a sulfated diatomaceous earth layer 16 and a silica gel layer 14 are packed in this order from the bottom of the column are provided. In the pretreatment column for dioxin analysis of the present invention which is connected, after introducing n-hexane 10 mL and washing with n-hexane, the diatomaceous earth column 10 from the top of the silica gel layer 14 dioxin-containing analyte sample Add 1 mL, then add 5 mL dichloromethane wash and let stand for 15 minutes. Next, 10 mL of n-hexane is added to the diatomaceous earth column 10 from above the silica gel layer 14, and 30 mL of a mixed solution (2: 1) of n-hexane and dichloromethane is flown.
In this way, the contaminants in the sample to be analyzed are retained and separated in the silica gel layer 14, the diatomaceous earth sulfate layer 16 and the polar carrier layer 18 in the diatomaceous earth column 10, and the dioxins are eluted in the activated carbon column 20. Next, the activated carbon column 20 is removed from the diatomaceous earth column 10 and turned upside down, and the automatic liquid feeding system shown in FIG.
Attach to 100 lure adapter 150 of secondary conduit 150.
The automatic liquid delivery system 100 is operated to separate the solvent (toluene) from the solvent tank 110 into the auxiliary conduit 140 via the main conduit 130, and the solvent (toluene) in the auxiliary conduit 140 inside the constant temperature tank 120 (75 ° C) ( (Toluene) is heated to make it hot toluene (about 50 ℃), and this hot toluene is used as luer adapter.
It is supplied to the activated carbon column 20 via 150, and the sample to be analyzed for dioxins analysis is extracted from the activated carbon column 20.

Hereinafter, the present invention will be described in more detail with reference to Examples.

[0044]

[Example] Preparation of an analyte sample containing dioxins The concentration of dioxins collected from an urban river estuary is about 15
A high-temperature high-pressure solvent extractor (ASE
300: manufactured by Dionex Co., Ltd.), the step of applying a pressure of 2000 psi at 195 ° C. for 15 minutes was repeated twice, and 30 g of each bottom sample was extracted to prepare a crude extract of about 100 mL of toluene. Approximately 1 mL of this crude extract was rotovapped.
It concentrated until it became and the concentrated liquid was produced. Next, the flask containing the crude extract was washed with 5 mL of dichloromethane to prepare a washing liquid. The concentrated solution and the washing solution were combined and used as a standard sample. In the following examples, the sample to be analyzed containing dioxins prepared here was used as an actual sample. Example 1: Effect of amount of sulfuric acid added to diatomaceous earth layer A commercially available diatomaceous earth column (trade name: CE-1010 (1
0mL capacity), manufacturer name: Varian, diatomaceous earth 7g),
Sulfuric acid was added under the conditions shown in Table 1 to prepare a diatomaceous earth column of the present invention, and an internal standard substance (IS) was introduced.

[0045]

[Table 1]

An internal standard substance ( ¹³
2378 chlorine-substituted dioxins labeled with C) alone,
And, 2 to 4 ng of the internal standard substance was added to the actual sample of dioxin (a dioxin-containing soil of 30 g or 60 g was extracted with toluene using a high-temperature high-pressure solvent extractor (ASE300: manufactured by Dionex)) by natural dropping, After performing the pretreatment according to the procedure shown in FIG. 4, the measurement was performed using PolarisQ (ion trap mass spectrometer: Thermo Finnigan Co., USA).

FIG. 6 shows the relationship between the added amount of sulfuric acid and the diatomaceous earth column after the treatment. The impurities in the sample to be analyzed react with sulfuric acid and turn black. Therefore, it can be seen from FIG. 6 that most of the impurities that have reacted with sulfuric acid are retained in the sulfated diatomaceous earth layer. It can be seen that when the amount of sulfuric acid added is 10 mL (100% of the sulfuric acid retention capacity of the diatomaceous earth column), the sulfuric acid completely passes through the diatomaceous earth layer and reaches the lower part of the diatomaceous earth column. This means that a part of the impurities that should originally be retained in the sulfated diatomaceous earth layer has leaked because it has passed through the diatomaceous earth layer together with sulfuric acid.

Chromaticity was measured according to JIS K0101-10.1 to determine the change in color of the sample liquid with the change in the amount of sulfuric acid added. The results are shown in Table 2.
Shown in.

[0049]

[Table 2]

From Table 2, from 0 mL to 8 mL of sulfuric acid addition (from 0% to 80% of column retention capacity), the coloring of the sample liquid becomes lighter as the addition amount of sulfuric acid increases, and the addition amount of sulfuric acid is 10 mL.
It can be seen that the color of the sample solution becomes darker again at (100% of the column retention capacity). From this, as the addition amount of sulfuric acid increases, the retention capacity of contaminants in the diatomaceous earth layer increases, but when the addition amount of sulfuric acid reaches 100% of the retention capacity of the diatomaceous earth column,
It can be said that the leak amount is larger than the holding capacity of the diatomaceous earth layer. Further, when the added amount of sulfuric acid is 6 mL, the chromaticity is high, indicating that the sulfuric acid treatment is not sufficiently performed.

From the above experimental results, when using a diatomaceous earth column with a retention capacity of 10 mL to retain contaminants in the diatomaceous earth layer, add sulfuric acid in an amount of more than 6 mL and less than 10 mL to the diatomaceous earth layer. Is preferred, 7-9 mL, especially 8 mL
Is the optimum addition amount. Example 2: Effect of silica gel addition amount on diatomaceous earth column From Example 1, it was found that the optimum retention volume of contaminants was obtained when the addition amount of sulfuric acid was 8 mL. The effect of silica gel addition was investigated for the case of sulfuric acid addition of 8 mL and internal standard substance addition of 20 μL.

On the diatomaceous earth sulfate layer of the diatomaceous earth column prepared in Example 1 (sulfuric acid addition amount: 80% of the column retention volume),
Silica gel (2 g, 4 g and 6 g) was added and the silica gel layers were laminated. To each diatomaceous earth column (sulfuric acid + silica gel),
The actual sample of dioxin added with 2 to 4 ng of internal standard substance (30 g or 60 g of dioxin-containing soil extracted with toluene using a high-temperature high-pressure solvent extractor (ASE300: Dionex)) was loaded by natural dropping, and the figure The pretreatment shown in 4 was carried out, and the chromaticity of the change in color of the sample liquid due to the change in the amount of silica gel added was measured according to JIS K0101-10.1. The results are shown in Table 3.

[0053]

[Table 3]

It was visually observed that when the amount of silica gel added was 2 g, the color of the treatment liquid was light, but as the amount of silica gel added increased, the color of the treatment liquid became darker. This is because as the amount of silica gel added increases, the thickness of the silica gel layer increases, so it takes time for the sample to reach the diatomaceous earth sulfate layer on the downstream side of the silica gel layer, and the contact time with the diatomaceous earth sulfate layer becomes shorter. , It is considered that the impurities in the sample were not sufficiently retained in the diatomaceous earth sulfate layer.

From the results of this experiment, the present concentration / washing method (concentrated toluene solution 1 mL + wash dichloromethane solution 5) was used using a diatomaceous earth column with a holding capacity of 10 mL (sulfuric acid addition amount 80%).
It can be seen that the optimum amount of silica gel added when performing (mL) is 2 g to 4 g. Example 3: Effect on recovery rate of diatomaceous earth column Changes in recovery rate with changes in the amount of added sulfuric acid were investigated.

NK-LCS-AD PCDD / Fs standard mixture (We
llington Laboratories, Ontario, Canada) was used as a standard sample. A diatomaceous earth column without the addition of sulfuric acid
After washing with 10 mL of n-hexane and adding 1 mL of standard sample, 15
After standing for 10 minutes, 10 mL of n-hexane was added, and then 30 mL of n-hexane-dichloromethane (2: 1) was flown to elute the solution, which was measured with Polaris Q to determine the area value on the chromatogram. This area value was set as the recovery rate of 100%. Next, using sulfuric acid modified as shown in Table 4 and added to the diatomaceous earth column, the same procedure was performed to obtain the area on the chromatogram, and the area was compared with the value when sulfuric acid was not added. I asked for the rate. The results are shown in Table 4.

[0057]

[Table 4]

From Table 4, it can be seen that the recovery rate is highest when 2 mL of sulfuric acid is added to the diatomaceous earth column having a column holding capacity of 10 mL, and the recovery rate decreases as the amount of sulfuric acid added exceeds 2 mL. This is because the sulfuric acid coating on the diatomaceous earth layer varies, and the thinner the coating, the wider the passage of the solvent (channel), and the higher the flow rate, the larger part of the solvent will pass through the channel.
It is considered that this is because the efficiency of contact with the sample deteriorates and the recovery rate decreases.

Therefore, by controlling the flow rate and sufficiently diffusing the solvent, it is possible to suppress the channeling and improve the recovery rate. Therefore, a silica gel layer is provided on the upstream side of the diatomaceous earth sulfate layer to suppress the flow rate. The effect on the recovery rate was investigated.

As shown in Table 5 below, except that silica gel was laminated on the diatomaceous earth layer, the recovery rate was obtained in the same manner as in the case of measuring the change in recovery rate with the change in the addition amount of sulfuric acid. . The results are shown in Table 5.

[0061]

[Table 5]

From Table 5, it can be seen that the recovery rate can be improved by providing a silica gel layer (addition amount: 2 g to 4 g) on the upstream side of the diatomaceous earth sulfate layer and suppressing the flow rate of the sample. Example 4: Effect of diatomaceous earth column on chromatogram The effect of the silica gel layer on the chromatogram in the diatomaceous earth column of the present invention will be considered. The chromatogram obtained in Example 3 is shown in FIG. In the case where silica gel was not added, the influence of impurities was large even in the state of being diluted 2.5 times as compared with the other cases, and the peak was broken, and quantification was not possible. When 2 g of silica gel was added, a very clean spectromatogram was obtained. When 6 g of silica gel was added, the background level due to noise increased. It is considered that this is because the contact time of the sample with the diatomaceous earth sulfate layer became shorter. From this experimental result, it can be seen that the purification efficiency becomes highest when 2 g of silica gel is added. Example 5: Effect on recovery rate of activated carbon column Commercially available diatomaceous earth column used in Example 1 (trade name: CE-101
0 (10 mL capacity), manufacturer name: Varian, diatomaceous earth 7 g)
8 mL of sulfuric acid was added to form a diatomaceous earth layer of sulfuric acid, and then 2 g of silica gel was evenly laid on the top of the layer of diatomaceous earth sulfate to stack the silica gel layers, thereby preparing two diatomaceous earth columns of the present invention.

To each of the prepared diatomaceous earth columns of the present invention,
A commercially available activated carbon cartridge having physical properties as the activated carbon column of the present invention (Carboxen 1016: Sigma-Aldrich)
The pre-treatment column of the present invention is the one that has been connected to a commercially available activated carbon cartridge (Carb
oxen 1000: Sigma-Aldrich) was used as a control pretreatment column. Each of the activated carbon cartridge columns used here was an activated carbon cartridge having a cartridge capacity of 1 mL filled with 200 mg of graphite carbon, and Table 6 shows the difference in physical properties between the two.

[0064]

[Table 6]

The pretreatment columns of the present invention and the control were loaded with 100 μL of an internal standard substance ( ^13C- labeled 2378 chlorine-substituted dioxins) diluted with 1 mL of toluene, and developed with 5 mL of dichloromethane. Next, the control pretreatment column was washed with 30 mL of n-hexane, and then with 30 mL of a mixed solution of n-hexane: dichloromethane (2: 1) (wash solution). on the other hand,
The pretreatment column of the present invention was washed with 30 mL of n-hexane, and then the n-hexane: dichloromethane mixed solution (3: 1) 30
It was washed with mL, and further with 30 mL of a mixed solution of n-hexane: dichloromethane (1: 1) (washing solution).

Both the pretreatment column of the present invention and the control pretreatment column were removed from the diatomaceous earth column, turned upside down, and a constant temperature pump was used to heat toluene at 50 ° C. until no internal standard substance was detected. I continued to run.
The total amount eluted was 100%, and the amount of toluene added was 30 mL.
The eluate fraction of each was analyzed using PolarisQ to obtain the recovery rate. The results are shown in Fig. 7.

FIG. 7 (a) shows the fluctuation of the recovery rate by the pretreatment column of the present invention, and FIG. 7 (b) shows the fluctuation of the recovery rate by the control pretreatment column. In the figure, T4-P5CDD / F is tetrachlorinated and pentachlorinated dioxin, H6CDD / F is 6 chlorinated dioxin and dibenzofuran, and H7-O8CDD / F is 7 chlorinated and 8 chlorinated dioxin and 7 chlorinated. Non-ortho PCBs are dibenzofurans with octachlorination, and non-ortho PCBs are coplanar PCBs in which chlorine is not substituted at the ortho position. Mono-ortho PCBs are coplanar PCBs in which only one chlorine is substituted at the ortho position. Table 7 shows the recovery rate of dioxins in each fraction.

[0068]

[Table 7]

From FIG. 7 and Table 7, in the case of the pretreatment column of the present invention, the amount of warm toluene added required to achieve a recovery rate of 99% or more is 60 mL, whereas the control pretreatment is It can be seen that 250 mL or more is required in the case of a column.
In the control pretreatment column, 60 mL of toluene was added to obtain about 70
The recovery rate is more than%, but the recovery rate after that is extremely low. It is considered that this is because the dioxins adsorbed to the mesopores on the surface of the activated carbon were first eluted and the elution efficiency of the dioxins adsorbed to the micropores located deeper than the mesopore layer was low. On the other hand, in the pretreatment column of the present invention, not only the surface of the activated carbon but also the mesopore layer immediately below the surface are present.Therefore, after the dioxin adsorbed on the surface mesopores is eluted, it is adsorbed to the mesopore layer immediately below the surface. Since the elution of dioxins that had been used progresses and the elution efficiency is high, 99
It is considered that more than 100% of dioxins were eluted.

[0070]

INDUSTRIAL APPLICABILITY According to the present invention, a dioxin for carrying out an effective pretreatment method for an analytical sample to be subjected to dioxin analysis while maintaining a high recovery rate rapidly, simply and inexpensively with good reproducibility. A pretreatment column for class analysis is provided.

By using the pretreatment column for dioxins analysis of the present invention, it is possible to effectively prepare an analytical sample to be subjected to dioxins analysis quickly, simply and inexpensively with good reproducibility and maintaining a high recovery rate. A treatment method can be implemented.

Further, according to the pretreatment method using the pretreatment column for the sample to be analyzed containing dioxins of the present invention, JIS
Instead of the complicated sulfuric acid treatment and alumina column chromatographic operation by the complicated silica gel column chromatographic operation or multilayer silica gel chromatographic operation specified in K0311, pretreatment can be performed very easily, and for various isomers Is also effective, the number of dioxins extraction and purification steps can be reduced, and the extremely time-consuming dioxin analysis pretreatment step can be completed in a very short time.

[Brief description of drawings]

FIG. 1 is a flowchart of a pretreatment for dioxins analysis according to JIS K0311 (1999).

FIG. 2 is a sectional view schematically showing the structure of a pretreatment column for dioxins analysis of the present invention.

FIG. 3 is a flow chart of a method for preparing a pretreatment column for dioxins analysis according to the present invention.

FIG. 4 is a flowchart of the pretreatment method for dioxins analysis of the present invention.

FIG. 5 is a schematic diagram showing a schematic configuration of an automatic liquid feeding system used when performing a dioxin analysis pretreatment step using the pretreatment column for a dioxin-containing analyte sample of the present invention.

FIG. 6 is a chromatogram chart for changes in the amount of silica gel added to the diatomaceous earth column used in the pretreatment column for dioxins analysis of the present invention.

FIG. 7 (a) is a graph showing the fluctuation of the recovery rate by the pretreatment column of the present invention, and FIG. 7 (b) is a graph showing the fluctuation of the recovery rate by the control pretreatment column.

[Explanation of symbols]

10: Diatomaceous earth column 14: Silica gel layer 16: Diatomaceous earth layer of sulfate 18: Polar carrier layer 20: Activated carbon column 110: Solvent tank 120: Constant temperature bath 130: Main conduit 132: Splitter 140: Secondary conduit 150: Lure mouth adapter

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01J 20/28 B01J 20/28 Z G01N 1/10 G01N 1/10 A 30/04 30/04 P 30 / 48 30/48 C G J K Y // G01N 30/26 30/26 A 30/72 30/72 A F Term (reference) 2G052 AA20 AB11 AC03 AD14 AD26 AD46 EB11 ED01 ED07 ED11 FC06 FC11 FD09 GA24 GA27 HC28 JA07 4D017 AA01 BA04 CA03 CA05 CA06 CB01 DA02 EA01 EB01 4G066 AA05B AA22B AA70B BA23 BA25 DA08 FA12

Claims (10)

[Claims] 1. A pretreatment column for dioxins analysis, which comprises a diatomaceous earth column containing a sulfated diatomaceous earth layer obtained by retaining sulfuric acid in diatomaceous earth. 2. The pretreatment column for analysis of dioxins according to claim 1, wherein the diatomaceous earth sulfate layer holds 70 to 90% by volume of sulfuric acid of the diatomaceous earth column holding capacity. 3. The pretreatment column for analysis of dioxins according to claim 1, wherein the diatomaceous earth column further includes a silica gel layer arranged upstream of the diatomaceous earth sulfate layer. 4. The diatomaceous earth column further comprises a polar carrier layer disposed downstream of the sulfated diatomaceous earth layer for adsorbing organic matter in an amount of at least 10% by volume of the diatomaceous earth column retention volume. The pretreatment column for dioxins analysis according to any one of 1. 5. Further, on the downstream side of the diatomaceous earth column,
The pretreatment column for dioxins analysis according to any one of claims 1 to 4, wherein the diatomaceous earth column includes a removable activated carbon column. 6. The activated carbon column has a pore size of 2 nm.
Substantially free of micropores of less than 2-50n
The pretreatment column for dioxins analysis according to claim 5, which is an activated carbon column containing 0.1 mL / g or more of m mesopores. 7. A diatomaceous earth column packed with diatomaceous earth and an activated carbon column that can be attached to and detached from the diatomaceous earth column are combined so that the amount of diatomaceous earth packed in the diatomaceous earth column does not reach the bottom of the diatomaceous earth. A method for preparing a pretreatment column for dioxins analysis, which comprises adding sulfuric acid to form a sulfated diatomaceous earth layer holding sulfuric acid, and adding silica gel on the sulfated diatomaceous earth layer to form a silica gel layer . 8. A dioxin-containing analyte sample, which comprises introducing a dioxin-containing analyte sample into a dioxin-analyzing pretreatment column including a diatomaceous earth column containing a sulfated diatomaceous earth layer obtained by retaining sulfuric acid in diatomaceous earth. Pretreatment method. 9. An analysis sample containing dioxins is provided with a silica gel layer, a diatomaceous earth sulfate layer obtained by retaining sulfuric acid in diatomaceous earth, a polar carrier layer for adsorbing organic matter, and a pore size of 2n.
Substantially no micropores less than m and pore size 2 ~
A method for pretreating an analyte sample containing dioxins, which comprises sequentially introducing mesopores of 50 nm into an activated carbon layer containing 0.1 mL / g or more. 10. A solvent bath provided with a flow rate control means for controlling the flow rate of the solvent, a constant temperature bath for heating the solvent, a solvent supply station for supplying the solvent heated in the constant temperature bath to an object to be supplied, A main conduit provided between the solvent tank and the constant temperature tank for flowing a solvent, connected to the main conduit outside the constant temperature tank upstream side, and connected to the solvent supply station outside the constant temperature tank downstream side. An automatic liquid feeder comprising one or more auxiliary conduits made of a corrosion-resistant, pressure-resistant and heat-resistant material.