JP2010169676A - Quantitative determination method of polychlorinated biphenyl - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an analysis method for quantitatively determining polychlorinated biphenyls by fully removing, with an easy operation, coexistent material disturbing the quantitative determination of the polychlorinated biphenyls from a hydrophobic sample containing the polychlorinated biphenyls. <P>SOLUTION: In this method, the hydrophobic sample containing the polychlorinated biphenyls is treated by gel permeation chromatography, a dispensed object that is obtained by the treatment and is mainly made of polychlorinated biphenyls is used; and the polychlorinated biphenyls is quantitatively determined by a gas chromatograph. The dispensed object useful for the gas chromatograph, after the treatment by the gel permeation chromatography is previously treated by concentrated sulfuric acid, then polychlorinated biphenyls are quantitatively determined using the gas chromatograph. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for quantifying polychlorinated biphenyls, and more particularly to a method for quantifying polychlorinated biphenyls in a hydrophobic sample.

  Polychlorinated biphenyls [hereinafter sometimes abbreviated as PCBs] contained in hydrophobic samples such as insulating oil used in transformers and the like. ], It is necessary to remove in advance the coexisting substances that interfere with the quantification of PCBs. However, such coexisting substances cannot be separated by ordinary processing methods such as column chromatography. Some are difficult. Therefore, Non-Patent Document 1 [Attached Table 2 “Special Management General Waste and Special Management Industry of July 3, 1992 revised by the Ministry of Health, Labor and Welfare Notification No. 633 on December 28, 2000” In the so-called official method described in “Standard Test Method for Waste”], after repeating the operation of bringing a hydrophobic sample into contact with concentrated sulfuric acid in liquid-liquid contact, the coexisting substances are subjected to the above column chromatographic treatment. The method of removing by such processing methods is disclosed. Further, as a similar pretreatment for PCB analysis in insulating oil, Non-Patent Document 2 [Pretreatment method using gel chromatography in analysis of PCBs in insulating oil: Environmental Chemistry Vol. 13, no. 4, pp. 1033-1040, 2003], a sample is treated with sulfuric acid, and then gel permeation chromatography [hereinafter abbreviated as GPC]. ] Is disclosed.

  The method of treating a hydrophobic sample containing PCBs with concentrated sulfuric acid before the treatment with GPC decomposes coexisting substances that hinder the determination of PCBs contained in the insulating oil, and GPC This is an extremely effective method because PCBs can be separated from a hydrophobic sample, and these decomposition products can be separated together.

  However, in the combined method in which the sample is pre-treated with concentrated sulfuric acid and then treated with GPC, coexisting substances that are difficult to separate from PCBs cannot be sufficiently removed, and further excellent removal is achieved. The emergence of methods is desired.

December 28, 2000 Ministry of Health, Labor and Welfare Notification No. 633, revised on July 3, 1992 Ministry of Health, Labor and Welfare Notification No. 192, Appendix 2 “Examination Methods for Standards Related to Specially Managed General Waste and Specially Managed Industrial Waste” " Pretreatment method using gel chromatography in PCBs analysis in insulating oil: Environmental Chemistry Vol. 13, no. 4, pp. 1033-1040, 2003

  In view of such circumstances, the present inventors have intensively studied to find a method for removing coexisting substances that hinder the quantification of PCBs from a more excellent hydrophobic sample. As a pre-treatment of hydrophobic samples containing sucrose, treatment with concentrated sulfuric acid, which was supposed to be performed prior to GPC treatment (separation of hydrophobic sample and PCBs), was applied to PCBs obtained after treatment with GPC. In the case of carrying out, the present inventors have found that coexisting substances that interfere with the quantification of PCBs are remarkably reduced, leading to the present invention.

  That is, the present invention treats a hydrophobic sample containing polychlorinated biphenyls by gel permeation chromatography, and then uses a fraction mainly composed of polychlorinated biphenyls obtained by the treatment, followed by polychlorination with a gas chromatograph. In the method for quantifying biphenyls, the present invention provides a method for quantifying polychlorinated biphenyls, characterized in that a fraction to be subjected to gas chromatography after gel permeation chromatography is treated with concentrated sulfuric acid in advance.

  The present invention also provides the method for quantifying polychlorinated biphenyls as described above, wherein the treatment with concentrated sulfuric acid is a liquid-liquid treatment of a fraction and concentrated sulfuric acid.

  Furthermore, the present invention provides the method for quantifying polychlorinated biphenyls as described above, wherein the treatment with concentrated sulfuric acid is a liquid-solid treatment of a fraction and sulfuric acid silica gel impregnated with concentrated sulfuric acid. There is.

  In addition, the present invention provides a method for quantifying polychlorinated biphenyls as described above, wherein the gas chromatograph is a high-resolution gas chromatograph.

  The present invention is a method for quantifying PCBs in a hydrophobic sample using a high-resolution gas chromatograph after treating a hydrophobic sample containing PCBs well known in the art with concentrated sulfuric acid and then with GPC. In comparison with this, the coexisting substances that interfere with the quantitative determination of PCBs can be significantly reduced.

2 is a chromatogram of used insulating oil of Company A obtained in Example 1. FIG. 2 is a chromatogram of used insulating oil of Company A obtained in Example 2. FIG. 2 is a chromatogram of a used insulating oil of Company A obtained in Comparative Example 1. 2 is a chromatogram of B company used insulating oil obtained in Example 3. FIG. 4 is a chromatogram of used insulating oil of Company C obtained in Example 3. 6 is a chromatogram of B company used insulating oil obtained in Example 4. FIG. 6 is a chromatogram of used insulating oil of Company C obtained in Example 4. FIG. 6 is a chromatogram of B company used insulating oil obtained by Comparative Example 2. 6 is a chromatogram of used insulating oil of Company C obtained in Comparative Example 2. It is a chromatogram of a PCB standard product.

The hydrophobic sample applied to the method of the present invention is a hydrophobic liquid sample, for example, an insulating oil that is used by being sealed in an electrical device such as a transformer or a condenser for insulation or cooling, the insulating oil And oily samples such as cracked oil obtained by cracking. Such an oily sample may be used as it is without being diluted, or may be diluted with a hydrophobic solvent such as n-hexane or cyclohexane.

  Examples of hydrophobic samples include solid samples such as soot discharged from incinerators, burning husks, soil samples collected from soil, water samples such as rainwater and drainage, n-hexane, toluene and the like. A hydrophobic solution containing PCBs extracted with a hydrophobic solvent is also mentioned.

  In order to extract PCBs from a solid sample or a water quality sample with a hydrophobic solvent, for example, the solid sample or the water quality sample may be brought into contact with the hydrophobic solvent as described above.

  The hydrophobic solvent extract obtained by extracting PCBs from a solid sample or a water quality sample with a hydrophobic solvent may be used as it is as a hydrophobic sample, but usually other coexistence extracted with PCBs. In order to separate the substances, PCBs are further extracted with a polar organic solvent from a hydrophobic solvent extract such as n-hexane or toluene, and the PCBs are transferred from the obtained polar organic solvent extract to a hydrophobic solvent. . Examples of such a polar organic solvent include dimethyl sulfoxide, acetonitrile, methanol, n-methylpyrrolidone and the like. In order to dissolve the polar organic solvent extract into the hydrophobic solvent, for example, water may be added to the polar organic solvent extract and then extracted with the hydrophobic solvent.

  In the practice of the present invention, a hydrophobic sample for quantifying PCBs is first subjected to GPC treatment. The GPC apparatus used in the present invention and its use conditions are not particularly limited. For example, LC-20AD & CTO-20A-sorting apparatus manufactured by Shimadzu Corporation, W2690-Fraction Collector II, 515 & 717 Plus-WFCIII manufactured by Waters, USA, etc. A graph unit (column layer and liquid feed pump) and a sorter attached are used. Moreover, CLNpak EV-2000 (inner diameter 20 mm, length 30 cm), CLNpak PAE-800 (inner diameter 8 mm, length 30 cm), etc. are used as a column used. As eluents, ethyl acetate / cyclohexane (volume ratio 3/7), flow rate 4.2 ml / min, hexane / acetone (volume ratio 70/30 to 90/10), flow rate 4 to 6 mL / min, and acetone / cyclohexane. (Volume ratio 95/5 to 80/20), a flow rate of 0.8 mL / min, etc. are used in combination with a column or the like. The column temperature may be lower than the boiling point of the eluent to be used, and is usually in the range of about 30 to 50 ° C.

Since the collected PCB eluate contains coexisting substances that interfere with the determination of PCBs, the coexisting substances that interfere with the determination of PCBs are decomposed by contacting with concentrated sulfuric acid. The treatment method using concentrated sulfuric acid is not particularly limited. For example, an organic solvent such as hexane or heptane is added to the PCB preparatory solution, and then the solution is supplied into the container. Concentrated sulfuric acid is added to the solution, and then gently using a stirrer or the like. Stir for 0.5-5 hours, usually 1-3 hours. The mixing ratio of the organic solvent containing the PCB fraction used for the sulfuric acid treatment and the concentrated sulfuric acid is not particularly limited, but the volume ratio may be 1: 1 to 5: 1, usually 2: 1 to 3: 1. . Moreover, you may concentrate and use the PCB fraction solution which adds an organic solvent by methods, such as solvent distillation, as needed. Further, the stirring treatment is performed for the purpose of decomposing coexisting substances which interfere with the determination of PCBs in the PCB preparative solution by sufficient contact between the PCB preparative solution and concentrated sulfuric acid. If so, for example, a method may be used in which the container is shaken and the PCB preparative solution is brought into contact with concentrated sulfuric acid. The processing liquid after stirring is transferred to a separating funnel and left to stand to separate the non-oil layer (mainly concentrated sulfuric acid) and the oil layer, and the non-oil layer is discarded. The treatment with sulfuric acid may be performed once, but may be performed a plurality of times as necessary. Next, an aqueous alkaline solution is added to the remaining oil layer to neutralize it, and then left to stand to separate the non-oil layer and the oil layer, and the non-oil layer is discarded. In order to remove water-soluble impurities remaining in the oil layer, pure water is added and mixed by shaking, and then left to stand to separate the non-oil layer and the oil layer, and the non-oil layer is discarded. Such a washing operation with pure water may be performed a plurality of times as necessary using the color of the non-oil layer, which has been allowed to stand and separate, as a judgment material. The oil layer after the water washing treatment is dehydrated by adding a dehydrating material or the like. The oil layer after the dehydration treatment is concentrated as necessary and used as a sample for quantifying polychlorinated biphenyls using a gas chromatograph. Since the sample used for a gas chromatograph is about 1 microliter normally, what is necessary is just to determine the sulfuric acid processing amount in connection with this.
In the present invention, concentrated sulfuric acid means sulfuric acid having a concentration of 90% (mass%) or more, usually sulfuric acid having a concentration of about 96 to about 98% (mass%), preferably a commercially available reagent special grade ( Application of a concentration of 98%) is recommended.

  The above method is a liquid-liquid treatment in which a so-called PCB eluate is treated with concentrated sulfuric acid. Alternatively, the PCB eluate may be treated with sulfuric acid silica gel impregnated with concentrated sulfuric acid. The sulfuric acid silica gel impregnated with concentrated sulfuric acid to be applied to the present invention is not particularly limited. For example, an empty glass fiber paper, silver nitrate silica gel layer, silica gel layer, sulfuric acid silica gel layer, and anhydrous sodium sulfate layer are sequentially laminated from the bottom of the container. A small filtration container (column) such as a reservoir may be used. A PCB preparatory solution may be introduced from the top into the dry sulfate silica gel / silver nitrate silica gel column formed as described above and contacted with sulfuric acid. The PCB fraction to be introduced into the column may be used after being concentrated by a method such as evaporation of the solvent, if necessary, or may be introduced into the column in a plurality of times. After the PCB fraction is introduced into the column, a solvent such as hexane is then introduced, and PCBs adhering to the column are eluted with a solvent such as hexane and collected in a container installed at the bottom of the column. The recovered solvent containing PCBs may be concentrated as necessary and used as a sample for quantifying polychlorinated biphenyls using a gas chromatograph.

  The sample after the sulfuric acid treatment may then be quantified for PCBs in the sample using a gas chromatograph. The gas chromatograph to be used is not particularly limited and may be any known one, but a high resolution gas chromatograph (capillary gas chromatograph) to which a capillary column can be attached is more desirable. The detector is not particularly limited and may be any known one. For example, a gas chromatograph equipped with a gas chromatograph-mass spectrometer (GC-MS) and an electron capture detector (ECD) [hereinafter, GC / Sometimes abbreviated as ECD. And the like.

  In the present invention, the sample after the liquid-liquid sulfuric acid treatment may be quantified as it is by polychromic biphenyls contained in the sample by gas chromatography, and if necessary, the oil layer (sample) after the dehydration treatment may be used as commercially available silica gel. The coexisting substances remaining in the oil layer may be further removed by passing through the packed bed. The treatment in the silica gel packed bed is performed, for example, by passing the sample after the sulfuric acid treatment through a silica gel column packed with silica gel, potassium hydroxide-coated silica gel, sulfuric acid-coated silica gel or the like in the column. The silica gel filler may be used alone in a column or may be used as a multilayer silica gel column having a multilayer structure. The sample after passing through the silica gel column may be concentrated by a method such as solvent distillation.

  As described above, when quantifying PCBs in a hydrophobic sample by gas chromatography, a method of performing sulfuric acid treatment after GPC treatment as a pretreatment method of the sample is the GPC after sulfuric acid treatment which has been generally performed. Compared with the method of treatment, it is not clear why the effect of removing coexisting substances that hinder the quantitative determination of PCBs is not clear, but when concentrated sulfuric acid is applied to a hydrophobic sample. At the same time as the coexisting substances are decomposed and removed, a new interfering substance is generated by the reaction of the hydrophobic sample component and concentrated sulfuric acid, and the purification efficiency reaches its peak, but the hydrophobic sample is treated with GPC prior to the sulfuric acid treatment, In the case of reacting with concentrated sulfuric acid, the amount of new interfering substances generated by the reaction between the hydrophobic sample and concentrated sulfuric acid is remarkably reduced, so that it is considered that the purification efficiency is improved.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by this Example.

Example 1
A used insulating oil of Company A was used, and PCBs contained in the insulating oil were analyzed by the GC / ECD method. In the analysis, pretreatment as a gas chromatograph sample was performed according to the following procedure and conditions. The analysis results are shown in FIG. In the figure, the range of about 8.5 min to about 32 min described on the horizontal axis is the PCB detection range. For comparison, a chromatogram of a standard PCB is shown in FIG.

(GPC processing)
Of the sample obtained by dissolving 0.8 g of used insulating oil in 5 mL of GPC eluent (ethyl acetate / cyclohexane --- volume ratio 3/7), 2 mL was injected into the GPC device, and the PCB elution range was fractionated. did. The fractionated solution was concentrated to 5 mL using a rotary evaporator, and n-hexane [Wako Pure Chemical Industries, “residual agricultural chemicals / PCB test 300”] was added thereto and diluted to 10 mL.

(Liquid-liquid sulfuric acid treatment)
Into a 100 mL Erlenmeyer flask, 10 mL of the diluted solution obtained by the above GPC treatment was transferred, and 10 mL of n-hexane [manufactured by Wako Pure Chemical Industries, Ltd., “300 for residual agricultural chemicals / PCB test”] was added, followed by concentrated sulfuric acid (concentration) 98%) [manufactured by Wako Pure Chemical Industries, Ltd., reagent grade 1] was added, and a stir bar was inserted and the mixture was gently stirred for 2 hours with a stirrer so that the internal sample did not fly off.

  After stirring, this solution was transferred to a 100 mL separatory funnel and separated into an oil layer (n-hexane sample solution) and a non-oil layer (sulfuric acid) by a stationary method, and the non-oil layer was discharged from the bottom of the separatory funnel. When transferring the solution, the inner wall of the Erlenmeyer flask was washed with n-hexane (same as above), and this washing solution was also transferred to a separating funnel.

  Next, 10 mL of a 0.1 mol / L potassium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd., reagent grade 1) was added to the above separating funnel from which the non-oil layer had been discharged, and after gently shaking by hand, about 5 minutes, The oil layer and the non-oil layer (KOH) were separated by standing, and the non-oil layer was discharged from the bottom of the separating funnel.

  Next, 10 mL of pure water is added so as to wash the wall surface from the upper part of the separating funnel from which the non-oil layer has been discharged. After gently shaking by hand, the oil layer and the non-oil layer (water) are left standing for about 5 minutes. The non-oil layer was separated and discharged from the bottom of the separatory funnel.

  The washing process with pure water was repeated again to discharge the non-oil layer, and then the oil layer remaining in the separatory funnel was transferred to a 100 mL beaker. When transferring the solution, the inner wall of the separatory funnel was washed with n-hexane (same as above), and this washing solution was also transferred into the same beaker as above.

  Next, 5 g of anhydrous sodium sulfate (manufactured by Wako Pure Chemical Industries, Ltd., “for residual pesticide test”) was added to the above beaker, gently stirred by hand, filtered and filtered using filter paper, and the oil layer after filtration was rotary. It concentrated to 1 mL with the evaporator.

(ECD measurement)
The n-hexane sample solution obtained above was quantified for PCBs by a gas chromatograph (with an ECD detector) [GC / ECD apparatus].

The configuration and conditions of the GC / ECD apparatus used for quantification are as follows.
Gas chromatograph part column: Capillary column: DB-5 ms [manufactured by J & W: length 30 m, inner diameter 0.25 mm, membrane pressure 0.1 μm]
Column temperature: 60 to 300 ° C. (temperature increase rate: 1 to 20 ° C./min)
Injection volume: 1 μL
Inlet temperature: 280 ° C
Carrier gas: helium gas, 1 mL / min

ECD temperature: 300 ° C

Example 2
Using the same insulating oil as in Example 1, except that the sulfuric acid treatment method as a gas chromatographic sample is different in the analysis, the PCBs contained in the insulation are GC / ECD under the same apparatus and conditions as in Example 1. Analyzed by the method. The result is shown in FIG. In the figure, the range of about 8.5 min to about 32 min described on the horizontal axis is the PCB detection range.

(GPC processing)
Of the sample obtained by dissolving 0.8 g of used insulating oil in 5 mL of GPC eluent (ethyl acetate / cyclohexane --- volume ratio 3/7), 2 mL was injected into the GPC device, and the PCB elution range was fractionated. did. This aliquot was concentrated to 0.5 mL using a rotary evaporator.

(Manufacture of sulfuric acid silica gel)
To a 1000 mL separatory funnel, 100 g of silica gel (Wako Pure Chemical Industries, Wakogel DX, 238-01781) is supplied, and 83 g of sulfuric acid (concentration 98%) (manufactured by Wako Pure Chemical Industries, reagent special grade) is added thereto, The mixture was shaken for about 1 hour until the additive became free flowing to obtain 44% silica gel.

(Manufacture of silver nitrate silica gel / sulfuric acid silica gel columns)
Put a glass fiber filter paper (Toyo RoshiKaisha, LTD ADVANTEC GLASS FIBER FILTER GA-100, 13mm) on a 6 mL polypropylene syringe (GL Science Co., Ltd., 5010-60102). First, 10% silver nitrate silica gel (Wako Pure Chemical Industries, Ltd.) , "Dioxins for analysis", 197-11611) 0.2g, and then 0.5g of silica gel (Wako Pure Chemical Industries, Wakogel DX, 238-01781) is placed on the 10% silver nitrate silica gel layer. Next, 2 g of 44% sulfuric acid silica gel produced by the above method was filled on the silica gel layer, and anhydrous sodium sulfate (made by Wako Pure Chemical Industries, “Residual agricultural chemical test”) was further put on the silica gel silica layer. 197-07125] 0.5 g was filled and laminated.

(Liquid-solid sulfuric acid treatment)
The syringe barrel (column) filled with the silver nitrate silica gel / sulfuric acid silica gel thus obtained is placed on a Spitz tube (inner diameter 16.5 mm, length 105 mm), and 0.5 mL of the concentrated solution obtained by GPC treatment is added. The paste was transferred to a syringe using a Pasteur pipette, and the filtrate was stored in a Spitz tube. The concentrated liquid container obtained by the GPC treatment was washed with about 1 mL of n-hexane [Wako Pure Chemical Industries, Ltd., “residual agricultural chemicals / PCB test 300”], and this washing liquid was transferred to a syringe. This operation was repeated until the amount of liquid stored in the Spitz tube became 7 mL, and then concentrated to about 0.5 mL using an automatic concentration apparatus (manufactured by Youth Engineering Co., Ltd., AUTOMATIC EVAPORATER ACMD-120). N-Hexane (Wako Pure Chemical Industries, “residual agricultural chemicals / PCB test 300”) was added thereto, and the volume was adjusted to 1 mL.

(ECD measurement)
PCBs were quantified by a gas chromatograph (with an ECD detector) [GC / ECD apparatus] using the n-hexane sample solution obtained by the liquid-solid sulfuric acid treatment. The configuration and conditions of the GC / ECD apparatus used for the determination are the same as those in Example 1.

Comparative Example 1
The same insulating oil as in Example 1 was used, and the PCBs contained in the insulation were GC / ECD using the same equipment and conditions as in Example 1 except that the pretreatment conditions as gas chromatographic samples were different during the analysis. Analyzed by the method. The result is shown in FIG. In the figure, the range of about 8.5 min to about 32 min described on the horizontal axis is the PCB detection range.

(Sulfuric acid treatment)
In a 100 mL Erlenmeyer flask, 0.8 g of the same used insulating oil (without PCB) as used in Example 1 and n-hexane [Wako Pure Chemical Industries, Ltd., “300 for residual agricultural chemicals / PCB test”] 20 mL was added, 10 mL of sulfuric acid (concentration 98%) (manufactured by Wako Pure Chemical Industries, Ltd., special grade reagent) was added thereto, and a stir bar was inserted, and the mixture was gently stirred for 2 hours so that the internal sample did not fly off.

  After stirring, this solution was transferred to a 100 mL separatory funnel and separated into an oil layer (n-hexane sample solution) and a non-oil layer (sulfuric acid) by a stationary method, and the non-oil layer was discharged from the bottom of the separatory funnel. When transferring the solution, the inner wall of the Erlenmeyer flask was washed with n-hexane (same as above), and this washing solution was also transferred to a separating funnel.

  Next, 10 mL of a 0.1 mol / L potassium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd., reagent grade 1) is added to the above separating funnel from which the non-oil layer has been discharged, and after shaking by hand, the mixture is left to stand for about 5 minutes. The oil layer and the non-oil layer (KOH) were separated by the method, and the non-oil layer was discharged from the lower part of the separating funnel.

  Next, 10 mL of pure water is added so as to wash the wall surface from the top of the separatory funnel from which the non-oil layer has been discharged. After shaking by hand, the oil layer and the non-oil layer (water) are separated by standing for about 5 minutes. The non-oil layer was discharged from the bottom of the separating funnel.

  The washing process with pure water was repeated again to discharge the non-oil layer, and then the oil layer remaining in the separatory funnel was transferred to a 100 mL beaker. When transferring the solution, the inner wall of the separatory funnel was washed with n-hexane (same as above), and this washing solution was also transferred into the same beaker as above.

  Next, 5 g of anhydrous sodium sulfate (manufactured by Wako Pure Chemical Industries, Ltd., “for residual pesticide test”) was added to the above beaker, gently stirred by hand, filtered and filtered using filter paper, and the oil layer after filtration was rotary. The solution was concentrated to 3 mL with an evaporator.

(GPC processing)
3 mL of the concentrated solution (n-hexane sample solution) obtained by the sulfuric acid treatment was made up to 5 mL with a GPC eluent (ethyl acetate / cyclohexane--volume ratio 3/7). 2 mL of the sample thus obtained was injected into the GPC apparatus, and the PCB elution range was fractionated. Then, this fractionated solution was concentrated using a rotary evaporator (to 0.5 mL), and n-hexane (Wako Pure Chemical Industries, Ltd., “residual agricultural chemicals / PCB test 300”) was added thereto to a constant volume of 1 mL. did.

(ECD measurement)
PCBs were quantified by a gas chromatograph (with an ECD detector) [GC / ECD apparatus] using the n-hexane sample solution obtained by the GPC treatment. The configuration and conditions of the GC / ECD apparatus used for the determination are the same as those in Example 1.

Example 3
PCBs contained in the insulating oil were analyzed by GC / ECD method using the insulating oil used by Company B and the insulating oil used by Company C. In the analysis, pretreatment as a gas chromatograph sample was performed according to the following procedure and conditions. FIG. 4 shows the analysis result of the used insulating oil of Company B, and FIG. 5 shows the analysis result of the used insulating oil of Company C. In the figure, the range of about 8.5 min to about 32 min described on the horizontal axis is the PCB detection range.

(GPC processing)
Of the sample obtained by dissolving 0.7 g of used insulating oil in 5 mL of GPC eluent (ethyl acetate / cyclohexane --- volume ratio 3/7), 2 mL was injected into the GPC device, and the PCB elution range was fractionated. did. The fractionated solution was concentrated to 5 mL using a rotary evaporator, and n-hexane [Wako Pure Chemical Industries, “residual agricultural chemicals / PCB test 300”] was added thereto and diluted to 10 mL.

(Liquid-liquid sulfuric acid treatment)
Into a 100 mL Erlenmeyer flask, 10 mL of the diluted solution obtained by the above GPC treatment was transferred, and 10 mL of n-hexane [manufactured by Wako Pure Chemical Industries, Ltd., “300 for residual agricultural chemicals / PCB test”] was added, followed by concentrated sulfuric acid (concentration) 98%) [manufactured by Wako Pure Chemical Industries, Ltd., reagent grade 1] was added, and a stir bar was inserted and the mixture was gently stirred for 2 hours with a stirrer so that the internal sample did not fly off.

  After stirring, this solution was transferred to a 100 mL separatory funnel and separated into an oil layer (n-hexane sample solution) and a non-oil layer (sulfuric acid) by a stationary method, and the non-oil layer was discharged from the bottom of the separatory funnel. When transferring the solution, the inner wall of the Erlenmeyer flask was washed with n-hexane (same as above), and this washing solution was also transferred to a separating funnel.

  Next, 10 mL of a 0.1 mol / L potassium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd., reagent grade 1) was added to the above separating funnel from which the non-oil layer had been discharged, and after gently shaking by hand, about 5 minutes, The oil layer and the non-oil layer (KOH) were separated by standing, and the non-oil layer was discharged from the bottom of the separating funnel.

  Next, 10 mL of pure water is added so as to wash the wall surface from the upper part of the separating funnel from which the non-oil layer has been discharged. After gently shaking by hand, the oil layer and the non-oil layer (water) are left standing for about 5 minutes. The non-oil layer was separated and discharged from the bottom of the separatory funnel.

  The washing process with pure water was repeated again to discharge the non-oil layer, and then the oil layer remaining in the separatory funnel was transferred to a 100 mL beaker. When transferring the solution, the inner wall of the separatory funnel was washed with n-hexane (same as above), and this washing solution was also transferred into the same beaker as above.

  Next, 5 g of anhydrous sodium sulfate (manufactured by Wako Pure Chemical Industries, Ltd., “for residual pesticide test”) was added to the above beaker, gently stirred by hand, filtered and filtered using filter paper, and the oil layer after filtration was rotary. It concentrated to 1 mL with the evaporator.

(ECD measurement)
The n-hexane sample solution obtained above was quantified for PCBs by a gas chromatograph (with an ECD detector) [GC / ECD apparatus].

The configuration and conditions of the GC / ECD apparatus used for quantification are as follows.
Gas chromatograph part column: Capillary column: DB-5 ms [manufactured by J & W: length 30 m, inner diameter 0.25 mm, membrane pressure 0.1 μm]
Column temperature: 60 to 300 ° C. (temperature increase rate: 1 to 20 ° C./min)
Injection volume: 1 μL
Inlet temperature: 280 ° C
Carrier gas: helium gas, 1 mL / min

ECD temperature: 300 ° C

Example 4
The same insulating oil as in Example 3 was used, and the PCBs contained in the insulation were the same as in Example 3 with the same apparatus and conditions as in Example 3, except that the GPC treatment and the sulfuric acid treatment method as a gas chromatograph sample were different. Analyzed by the GC / ECD method. FIG. 6 shows an analysis result of the used insulating oil of the B company, and FIG. 7 shows an analysis result of the used insulating oil of the C company. In the figure, the range of about 8.5 min to about 32 min described on the horizontal axis is the PCB detection range.

(GPC processing)
Used insulating oil 0.35g was melt | dissolved in hexane to 1.4mL, 0.5mL in it was inject | poured into the GPC apparatus, and the PCB elution range was fractionated. This aliquot was concentrated to 0.5 mL using a rotary evaporator.

(Manufacture of sulfuric acid silica gel)
To a 1000 mL separatory funnel, 100 g of silica gel (Wako Pure Chemical Industries, Wakogel DX, 238-01781) is supplied, and 83 g of sulfuric acid (concentration 98%) (manufactured by Wako Pure Chemical Industries, reagent special grade) is added thereto, The mixture was shaken for about 1 hour until the additive became free flowing to obtain 44% silica gel.

(Manufacture of silver nitrate silica gel / sulfuric acid silica gel columns)
Put a glass fiber filter paper (Toyo RoshiKaisha, LTD ADVANTEC GLASS FIBER FILTER GA-100, 13 mm) on a 6 mL polypropylene syringe (GL Science Co., Ltd., 5010-60102). First, 10% silver nitrate silica gel (Wako Pure Chemical Industries, Ltd.) , "Dioxins for analysis", 197-11611) 0.2g, and then 0.5g of silica gel (Wako Pure Chemical Industries, Wakogel DX, 238-01781) is placed on the 10% silver nitrate silica gel layer. Next, 2 g of 44% sulfuric acid silica gel produced by the above method was filled on the silica gel layer, and anhydrous sodium sulfate (made by Wako Pure Chemical Industries, “Residual agricultural chemical test”) was further put on the silica gel silica layer. 197-07125] 0.5 g was filled and laminated.

(Liquid-solid sulfuric acid treatment)
The syringe barrel (column) filled with the silver nitrate silica gel / sulfuric acid silica gel thus obtained is placed on a Spitz tube (inner diameter 16.5 mm, length 105 mm), and 0.5 mL of the concentrated solution obtained by GPC treatment is added. The paste was transferred to a syringe using a Pasteur pipette, and the filtrate was stored in a Spitz tube. The concentrated liquid container obtained by the GPC treatment was washed with about 1 mL of n-hexane [Wako Pure Chemical Industries, Ltd., “residual agricultural chemicals / PCB test 300”], and this washing liquid was transferred to a syringe. This operation was repeated until the amount of liquid stored in the Spitz tube became 7 mL, and then concentrated to about 0.5 mL using an automatic concentration apparatus (manufactured by Youth Engineering Co., Ltd., AUTOMATIC EVAPORATER ACMD-120). N-Hexane (Wako Pure Chemical Industries, “residual agricultural chemicals / PCB test 300”) was added thereto, and the volume was adjusted to 1 mL.

(ECD measurement)
PCBs were quantified by a gas chromatograph (with an ECD detector) [GC / ECD apparatus] using the n-hexane sample solution obtained by the liquid-solid sulfuric acid treatment. The configuration and conditions of the GC / ECD apparatus used for quantification are the same as those in Example 3.

Comparative Example 2
Using the same insulating oil as in Example 3 and analyzing the PCBs contained in the insulation with the same equipment and conditions as in Example 3, except that the pretreatment conditions as a gas chromatographic sample were different, GC / ECD was used. Analyzed by the method. FIG. 8 shows an analysis result of the used insulating oil of the B company, and FIG. 9 shows an analysis result of the used insulating oil of the C company. In the figure, the range of about 8.5 min to about 32 min described on the horizontal axis is the PCB detection range.

(Sulfuric acid treatment)
To a 100 mL Erlenmeyer flask, 2.5 g of the same used insulating oil as used in Example 3 and 20 mL of n-hexane (Wako Pure Chemical Industries, Ltd., “300 for residual agricultural chemicals / PCB test”) were added. 10 mL of sulfuric acid (concentration 98%) [manufactured by Wako Pure Chemical Industries, Ltd., reagent grade] was added, and a stir bar was added and gently stirred for 2 hours with a stirrer so that the internal sample did not fly off.

  After stirring, this solution was transferred to a 100 mL separatory funnel and separated into an oil layer (n-hexane sample solution) and a non-oil layer (sulfuric acid) by a stationary method, and the non-oil layer was discharged from the bottom of the separatory funnel. When transferring the solution, the inner wall of the Erlenmeyer flask was washed with n-hexane (same as above), and this washing solution was also transferred to a separating funnel.

  Next, 10 mL of a 0.1 mol / L potassium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd., reagent grade 1) is added to the above separating funnel from which the non-oil layer has been discharged, and after shaking by hand, the mixture is left to stand for about 5 minutes. The oil layer and the non-oil layer (KOH) were separated by the method, and the non-oil layer was discharged from the lower part of the separating funnel.

  Next, 10 mL of pure water is added so as to wash the wall surface from the top of the separatory funnel from which the non-oil layer has been discharged. After shaking by hand, the oil layer and the non-oil layer (water) are separated by standing for about 5 minutes. The non-oil layer was discharged from the bottom of the separating funnel.

  The washing process with pure water was repeated again to discharge the non-oil layer, and then the oil layer remaining in the separatory funnel was transferred to a 100 mL beaker. When transferring the solution, the inner wall of the separatory funnel was washed with n-hexane (same as above), and this washing solution was also transferred into the same beaker as above.

  Next, 5 g of anhydrous sodium sulfate (manufactured by Wako Pure Chemical Industries, Ltd., “for residual pesticide test”) was added to the above beaker, gently stirred by hand, filtered and filtered using filter paper, and the oil layer after filtration was rotary. The solution was concentrated to 3 mL with an evaporator.

(GPC processing)
3 mL of the concentrated solution (n-hexane sample solution) obtained by the sulfuric acid treatment was made up to 5 mL with a GPC eluent (ethyl acetate / cyclohexane--volume ratio 3/7). 2 mL of the sample thus obtained was injected into the GPC apparatus, and the PCB elution range was fractionated. Then, this fractionated solution was concentrated using a rotary evaporator (to 0.5 mL), and n-hexane (Wako Pure Chemical Industries, Ltd., “residual agricultural chemicals / PCB test 300”) was added thereto to a constant volume of 1 mL. did.

(ECD measurement)
PCBs were quantified by a gas chromatograph (with an ECD detector) [GC / ECD apparatus] using the n-hexane sample solution obtained by the GPC treatment. The configuration and conditions of the GC / ECD apparatus used for quantification are the same as those in Example 3.

  As is apparent from the chromatograms of Examples 1 to 4, Comparative Example 1 and Comparative Example 2, a sample pretreatment method for treating a sample made of a hydrophobic solution with concentrated sulfuric acid, which is a conventional method, followed by GPC treatment It can be seen that the method of the present invention in which concentrated sulfuric acid treatment is performed after GPC treatment can significantly reduce the coexisting substances that hinder the determination of PCBs.

  According to the present invention, in a method of quantifying polychlorinated biphenyls from a hydrophobic sample containing PCBs using a gas chromatograph, the quantification of PCBs can be carried out by an extremely simple treatment method compared to a conventionally known pretreatment method. Since the coexisting substances that interfere can be significantly reduced, PCBs can be easily and accurately quantified, and the applicability in industrial fields such as waste disposal is great.

Claims (4)

  A hydrophobic sample containing polychlorinated biphenyls is treated by gel permeation chromatography, and then the fraction of polychlorinated biphenyls obtained by the treatment is used to determine the amount of polychlorinated biphenyls by gas chromatography. A method for quantifying polychlorinated biphenyls, characterized in that a fraction to be subjected to gas chromatography after gel permeation chromatography is treated with concentrated sulfuric acid in advance.   2. The method for quantifying polychlorinated biphenyls according to claim 1, wherein the treatment with concentrated sulfuric acid is a liquid-liquid treatment of a fraction and concentrated sulfuric acid.   2. The method for quantifying polychlorinated biphenyls according to claim 1, wherein the treatment with concentrated sulfuric acid is a liquid-solid treatment between a fraction and a sulfuric acid silica gel impregnated with concentrated sulfuric acid.   The method for quantifying polychlorinated biphenyls according to claim 1, wherein the gas chromatograph is a high-resolution gas chromatograph.

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