JP4194081B2 - Microanalysis of polychlorinated dibenzo-p-dioxins and / or polychlorinated dibenzofurans - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to polychlorinated dibenzo-p-dioxins (PCDD _S ), including 2,3,7,8-tetrachlorodioxin (T ₄ CDD), which are considered to be the most toxic among synthetic organic compounds, as well as extremely toxic Relates to a microanalysis method of polychlorinated dibenzofuran (PCDF _S ).
[0002]
[Prior art]
Conventionally, a technique using activated carbon-embedded silica gel obtained by reacting a mixture of sodium silicate (water glass) and activated carbon with a mineral as a filler for a clean-up column has been disclosed (see Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Publication No. 7-50084
As a result, compared with the case where silica gel or alumina is conventionally used alone as a packing material for the column in the cleanup process, activated carbon has a planar structure (flat plate structure) such as PCDD _S or PSDS _{S in} activated carbon embedded silica gel. to have the ability to specifically adsorb molecules with, since the components of the PCB _S and high-boiling hydrocarbons to be quantified interference in the mass spectrometer can be completely removed, PCDD _S by GS-MS, the PCDF _S It is possible to perform the fractionation of isomers very effectively.
[0005]
However, actual analysis of dioxins is currently performed by combining various column chromatography such as silica gel column, alumina column, and activated carbon embedded silica gel, and the selectivity of the adsorbent of the column is low and complicated. It was necessary to repeat the cleanup operation, and the analysis cost was expensive. Therefore, the present inventors have developed a packing material for a clean-up column that can perform analysis with higher accuracy in trace analysis of PCDD _S and PCDF _S (see Patent Document 2).
[0006]
[Patent Document 2]
Japanese Patent Laid-Open No. 2001-330597
This is an intercalation reaction between the host graphite and the guest incorporated between the graphite layers, and then the expanded graphite obtained by heat treatment and silica gel are mixed and used as a packing material for the cleanup column. Is. When this filler is used, planar compounds such as PCDD _S and PCDF _S molecules are easily adsorbed, and are easily eluted when an organic solvent is added. Therefore, the cleanup can be remarkably improved, and the operation is highly accurate. It is possible to perform microanalysis of PCDD _S and PCDF _S which are excellent in performance.
[0008]
However, even with the above fillers, it is difficult to completely remove substances other than dioxins such as PCDD _S and PCDF _S, and there is a problem that some substances are mixed into the section where dioxins are eluted and become noise. there were. In addition, the process for producing the filler includes an intercalation reaction of expensive graphite fluoride powder and high-temperature heat treatment at about 400 ° C. in an inert gas, and includes pretreatment and cleaning steps. Manufacturing costs are expensive because it requires a minimum of 4 days of production.
[0009]
[Problems to be solved by the invention]
In view of the above problems, it is a technical object of the present invention to provide an analysis method using a packing agent for a clean-up column that is easy to manufacture and that can be analyzed with high accuracy at a low manufacturing cost. .
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention of claim 1 is a microanalysis method of polychlorinated dibenzo-p-dioxin and / or polychlorinated dibenzofuran. Heating around 700 ° C. for about 30 minutes completely removes the crystallites composed of condensed benzene rings with π electrons and the impurities remaining in the gaps between the primary particles, the specific adsorptivity of dioxins, and toluene After the treatment to improve both the elution properties of dioxins by a secondary solvent, etc., the fine powdered conductive carbon black is mixed with silica gel 1 at a 1 to 10% weight ratio to produce an adsorbent. Step 2) Fill the column chromatography tube with quartz wool, anhydrous sodium sulfate, the above adsorbent and anhydrous sodium sulfate in this order to create a column chromatography tube. 3) Set the column chromatograph tube in the fraction collector and let the analytical sample flow down 4) Let the sample flow for 30 minutes and let the column adsorb dioxin 5) Let it stand for 30 minutes Thereafter, elution with 200 ml of 25% dichloromethane / hexane and fractionation with a fraction collector, 6) elution with 200 ml of toluene after completion of elution of the above 25% dichloromethane / hexane with 200 ml, and fractionation with the same fraction collector, 7) After completion of fractionation, the fraction eluted with 25% dichloromethane / hexane was added with 2 ml of isooctane, and then 25% dichloromethane / hexane was evaporated with nitrogen and the extracted components were dissolved in isooctane. And 8) 9,10-dichloroanthracene 13 as an internal standard in the fraction. Analysis method characterized by comprising the steps of measuring by GC / ECD in addition to be 0.27ppm to ppm, it took technical means of.
[0011]
[0012]
[0013]
When the adsorbent produced in the above step 1) is used as a packing material for the column in the cleanup step, and the sample is poured with a solvent such as hexane as in the above steps 3) to 5), only dioxins to be fractionated are obtained. It can be adsorbed on the filler. Thereafter, the dioxins adsorbed on the filler are eluted using a solvent such as toluene as in the above step 6). At this time, when heat is applied from outside and inside, the dioxins are quickly eluted. Can be made.
[0014]
The conductive carbon black has a structure in which primary particles in which crystallites composed of condensed benzene rings having π (pi) electrons gather are gathered in a complicated manner and have a property of being finely dispersed. Moreover, since it has an extremely large surface area and good thermal conductivity, dioxins are eluted from the adsorbent in a very short time.
[0015]
Further, when conductive carbon black is heated at a temperature of about 500 to 700 ° C. for about 30 minutes, the adsorption capacity and elution of dioxins are remarkably improved. The reason for this is that, by heating, impurities remaining in the gaps between the crystallites and the primary particles are completely removed, and the gaps between the crystallites and the aggregated primary particles are opened to facilitate the inflow and elution of dioxins. It is possible that Furthermore, by performing the above steps 7) and 8), it is possible to analyze dioxins with extremely high accuracy.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The properties of the conductive carbon black used in the present invention are shown below.
[0017]
Carbon black is so-called “soot” and is composed of carbon like graphite. Applications are used for inks, toners, paints, etc., resins, batteries, and other electrode materials. The crystallite is composed of a benzene ring in the same manner as graphite, and some of the crystallites exhibit remarkable conductivity due to the movement of π electrons in the condensed benzene ring.
As a feature of conductive carbon black,
1. Small particle size.
2. Specific surface area is extremely large (800-1400m ² / g).
3. Be porous.
4). There is much oil absorption (790-1050 mg / g).
5. Development of a structure in which primary particles are fused.
6). Structures are joined together to form a network structure.
Is mentioned.
[0018]
Typical examples of the conductive carbon black include ketjen black (trade name) manufactured by Ketjen Black International, acetylene black (trade name) manufactured by Denki Kagaku Kogyo. Among them, ketjen black has the above-mentioned characteristics, and it is known that when the resin is filled, the conductivity of the resin is remarkably improved.
[0019]
Carbon black crystallites are nanometer-sized fine particles in which benzene rings are layered, and have the property of specifically adsorbing a planar structure (flat plate structure) material such as dioxins. In particular, conductive carbon black has a structurally strong adsorptive power, and among them, ketjen black has a remarkably high adsorbing ability. As it is, other substances other than dioxins are adsorbed and elution with a secondary solvent such as toluene is insufficient, but by heating conductive carbon black at 500 to 700 ° C. for about 30 minutes, Due to the arrangement of layered benzene rings and the removal of impurities, the specific adsorption property of dioxins and the elution property with toluene are remarkably improved, and the adsorbent packing for the cleanup column for fractionation of dioxins is excellent. It becomes. In the elution step of dioxins with a secondary solvent, if the adsorbent is warmed, its elution performance will be greatly improved. However, in order to perform the heating with good response, conductive carbon black having high thermal conductivity (especially Ketjen Black) is the best.
[0020]
As a column heating method, a method of heating the outside of the column with a temperature-controlled heater, a method of mounting a ceramic heater inside the column, a method of applying heat rays, a method of applying microwaves, and the like are conceivable.
[0021]
[Example 1]
Step 1: Create an adsorbent.
As test adsorbents, (1) activated carbon embedded silica gel (conventional product), (2) expanded graphite fluoride (conventional product), and (3) ketjen black (heated once at 500 ° C in air) , (4) Ketjen black (heated once at 600 ° C in air), (5) Ketjen black (heated once in air at 700 ° C), (6) Mixture of silica gel and ketjen black Six types (1 g of silica gel and 0.02 g of ketjen black (heated once at 700 ° C. in air)) were used.
Step 2: Create a column chromatography tube.
The column chromatography tube was packed in the order of quartz wool (small amount), anhydrous sodium sulfate (small amount), the test adsorbent, and anhydrous sodium sulfate (small amount).
Operation 3: Set the prepared column chromatograph tube in a fraction collector (Advantech, model SF-2120), and let the analysis sample flow down.
Operation 4: Allow the sample to stand for 30 minutes after flowing down to adsorb dioxin on the column (At this time, in order to prevent the flowed analysis sample from getting below the adsorbent layer, wash with about 400 μl of hexane. It was used).
Operation 5: The mixture was allowed to stand for 30 minutes, eluted with 25 ml of dichloromethane / hexane 200 ml, and fractionated with a fraction collector.
Procedure 6: After completion of elution with 25% dichloromethane / hexane 200 ml, elution with 200 ml of toluene, and fractionation with a fraction collector in the same manner.
Step 7: After fractionation is completed, add 2 ml of isooctane to the fraction eluted with 25% dichloromethane / hexane, concentrate with nitrogen, and dissolve in isooctane.
Operation 8: An internal standard substance (9,10-dichloroanthracene: 135 ppm) was added to the fraction so as to be 0.27 ppm, and measurement was performed by GC / ECD.
[0022]
As an analysis sample,
2,3,7-trichloride dioxin (T ₃ CDD): 40 μl (50 ppm)
1,3,7,9-Tetrachloride dioxin (T ₄ CDD): 40 μl (50 ppm)
1,2,3,4,6,7,8,9-octachloride dioxin (OCDD): 20 μl (50 ppm)
2,2 ′, 3,4,4 ′, 5,5′-biphenyl heptachloride (H ₇ CB): 28 μl (35 ppm)
Dieldrin: 2μl (170ppm)
p, p′-DDT: 2 μl (100 ppm)
Isooctane: 168 μl
7 types were used.
[0023]
Fig. 1 shows the fractionation results when using activated carbon-embedded silica gel, Fig. 2 shows the fractionation results when using expanded graphite fluoride, and Fig. 3 shows ketjen black (1 at 500 ° C in air). Fig. 4 shows the fractionation results when using ketjen black (heated once at 600 ° C in air), and Fig. 5 shows the results of fractionation. Fig. 6 shows the results of fractionation using chain black (heated once at 700 ° C in air). Fig. 6 shows a mixture of silica gel and ketjen black (1 g of silica gel and ketjen black (1 in 700 ° C in air). It is the fractionation result when using the one that was mixed twice (0.02 g).
[0024]
Referring to FIG. 1, it can be seen that when a sample is fractionated by a column with a primary solvent or a secondary solvent, there are substances that are eluted for a long time, such as T4CB and OCDD, and it cannot be clearly fractionated. In addition, referring to FIG. 2, although it is superior to FIG. 1, it can be seen that some substances such as T ₄ CB require a long time for elution. As a result, substances that require a long time for elution may be mixed with other substances to be fractionated.
[0025]
Referring to FIG. 3 and FIG. 4, it can be seen that all the substances are clearly fractionated as compared with FIG. 1 or FIG. Further, referring to FIG. 5, it can be seen that although the result is not significantly higher than those of FIGS. 3 and 4, it is clearly fractionated. Since its adsorption characteristics are similar to those of Ketjen Black heated at 600 ° C, good results can be obtained by heating Ketjen Black at 600 ° C or higher.
[0026]
FIG. 6 uses a mixture of silica gel and ketjen black, but is more clearly fractionated than in FIGS.
[0027]
【The invention's effect】
As described above, according to the present invention, in the microanalysis method of polychlorinated dibenzo-p-dioxin and / or polychlorinated dibenzofuran, the following operation steps are performed: Heating around 30 minutes at temperature completely removes the crystallites composed of condensed benzene rings with π electrons and impurities remaining in the gaps between primary particles, specific adsorption of dioxins, and secondary such as toluene A process of producing an adsorbent by mixing the silica gel 1 with 1 to 10% by weight of the fine powdered conductive carbon black after performing a treatment to improve both the elution of dioxins by a solvent; ) Step of filling a column chromatography tube with quartz wool, anhydrous sodium sulfate, the above adsorbent and anhydrous sodium sulfate in this order to prepare a column chromatography tube, 3 The column chromatograph tube is set in a fraction collector, and the analysis sample is allowed to flow down. 4) The sample is allowed to stand for 30 minutes after flowing down, and the dioxin is adsorbed to the column. Elution with 200 ml of hexane / hexane and fractionation with a fraction collector, 6) Elution with 200 ml of toluene after completion of elution with the above 25% dichloromethane / hexane, and fractionation with a fraction collector in the same manner, 7) Completion of fractionation Thereafter, the fraction eluted with 25% dichloromethane / hexane was added with 2 ml of isooctane, and then the 25% dichloromethane / hexane was evaporated with nitrogen, and the extracted components were dissolved in isooctane, and 8) fractionation. As an internal standard substance, 0.15 ppm of 9,10-dichloroanthracene was added to the liquid. The analysis method is characterized by including the step of measuring by GC / ECD in addition to ppm, so that the manufacturing cost is reduced with a simple manufacturing process, and the analysis of dioxins with extremely high accuracy is possible. It can be carried out.
[0028]
In addition, it is possible to analyze dioxins with extremely high accuracy compared to the case where conventional activated carbon-embedded silica gel or expanded graphite fluoride is used.
[0029]
Furthermore, when dioxins are eluted, if heat is applied from the outside or the inside of the cleanup column, the dioxins can be eluted quickly.
[Brief description of the drawings]
FIG. 1 is a fractionation result when activated carbon-embedded silica gel is used.
FIG. 2 is a fractionation result when expanded graphite fluoride is used.
FIG. 3 is a fractionation result when using ketjen black (heated once in air at 500 ° C.).
FIG. 4 is a fractionation result when using ketjen black (heated once at 600 ° C. in air).
FIG. 5 is a fractionation result when using ketjen black (heated once at 700 ° C. in air).
FIG. 6 is a fractionation result when a silica gel and ketjen black mixture (1 g of silica gel and 0.02 g of ketjen black (heated once at 700 ° C. in air) is mixed) is used.

Claims (1)

In the microanalysis method of polychlorinated dibenzo-p-dioxin and / or polychlorinated dibenzofuran, the following operation steps are:
1) The fine powdered conductive carbon black is heated in advance at a temperature of 500 to 700 ° C. for about 30 minutes to completely remove impurities remaining in the gaps between the crystallites composed of condensed benzene rings having π electrons and the primary particles. Then, after the treatment to improve both the specific adsorption property of dioxins and the elution property of dioxins with a secondary solvent such as toluene, 1 to A process of mixing at a 10% weight ratio to produce an adsorbent,
2) A step of preparing a column chromatography tube by filling the column chromatography tube with quartz wool, anhydrous sodium sulfate, the adsorbent and anhydrous sodium sulfate in this order,
3) A step of setting the column chromatograph tube to a fraction collector and causing the analysis sample to flow down,
4) A step of allowing the sample to stand for 30 minutes after allowing the sample to flow and adsorbing dioxins on the column,
5) The step of elution with 25% dichloromethane / hexane 200 ml after standing for 30 minutes and fractionating with a fraction collector,
6) Step of eluting with 200 ml of toluene after elution of the above 25% dichloromethane / hexane 200 ml, and fractionating with a fraction collector,
7) After completion of fractionation, the fraction eluted with 25% dichloromethane / hexane was added with 2 ml of isooctane, and then 25% dichloromethane / hexane was evaporated with nitrogen and the extracted components were dissolved in isooctane. And 8) a step of adding 135 ppm of 9,10-dichloroanthracene as an internal standard substance to the fraction so as to be 0.27 ppm and measuring by GC / ECD,
An analysis method characterized by containing.

Images