JP6558040B2 - Analysis method - Google Patents

Description

  The present invention relates to an analysis method.

  From the viewpoint of impact on the environment, plasticizers containing low molecular weight compounds having a benzene ring, such as phthalates, are regulated. In addition, added plasticizers such as trimellitic acid esters also have adverse effects such as elution. For this reason, it is desired to easily qualify the plasticizer contained in the resin sample (see, for example, Patent Document 1).

  As a method for analyzing the plasticizer contained in the resin sample, gas chromatograph mass spectrometry, liquid chromatograph mass spectrometry, and the like are used. However, with these gas chromatograph mass spectrometry and liquid chromatograph mass spectrometry, it is possible to qualitatively qualify plasticizers. However, the analysis requires a great deal of man-hours and advanced technical skills. It takes a long time to obtain a measurement result when making a request to the institution.

  As a simple analysis method, an analysis method using thin layer chromatography (TLC: Thin Layer Chromatography) is known.

Japanese Patent Laid-Open No. 11-44678

  However, in thin layer chromatography, it is possible to identify the mixed components in the mobile phase by separating them into stationary phases. Here, when the plasticizer as the analysis target in the resin sample is dissolved in the extraction solvent, components (resins) other than the additive containing the plasticizer as the analysis target may be dissolved together. For this reason, when the extraction solution is applied to a plate for thin layer chromatography and developed, the resin not analyzed and the plasticizer to be analyzed are not separated, and it may be difficult to perform a qualitative analysis. . In addition, if the extraction capacity is reduced to prevent the inclusion of components other than the analysis target, the extraction efficiency of the target component may be reduced, and thin-layer chromatography using an extraction solvent is considered inefficient. There was also. For this reason, conventionally, it has been difficult to easily qualitatively analyze a plasticizer in a resin sample by a simple method.

  The present invention has been made in view of the above, and it is a main object of the present invention to provide an analysis method capable of easily qualitatively analyzing a plasticizer in a resin sample.

  The analysis method of the present invention is characterized in that the extraction solvent for thin layer chromatography of a resin sample containing at least a low molecular compound having a benzene ring as a plasticizer contains ethanol.

  According to the present invention, the plasticizer in the resin sample can be easily qualitatively analyzed.

The figure which shows the evaluation result of Example 5. FIG. The figure which shows the evaluation result of the comparative example 1.

  Hereinafter, embodiments of the analysis method will be described in detail.

  The analysis method according to the present embodiment is an analysis method using thin layer chromatography (TLC: Thin Layer Chromatography). The analysis object is a plasticizer contained in the resin sample. In the present embodiment, the plasticizer to be analyzed is a low molecular compound having at least a benzene ring.

  The present inventors have found that by using an extraction solvent containing ethanol as the extraction solvent, the plasticizer contained in the resin sample can be selectively dissolved in the extraction solvent. That is, it has been found that in the extraction solvent containing ethanol, components (for example, resin) other than the additive containing the plasticizer to be analyzed contained in the resin sample do not have remarkable solubility.

  For this reason, according to the formation analysis method of the present embodiment, it has been clarified that the plasticizer in the resin sample can be easily qualitated.

  Details will be described below.

<Resin sample>
The resin sample includes a plasticizer to be analyzed, a resin, a lubricant, a filler, and the like.

-resin-
The resin contained in the resin sample is not limited. Examples of the resin included in the resin sample include polyvinyl chloride, polyethylene, polypropylene, and polyester. The resin contained in the resin sample may contain two or more of the above resins.

―Plasticizer―
In the present embodiment, the plasticizer to be analyzed is a low molecular compound having at least a benzene ring.

  In the present embodiment, the term “low molecule” means that the weight average molecular weight is in the range of 1000 or less, and the number of binding molecules is 1 or more and 4 or less.

  The plasticizer to be analyzed in the present embodiment may be any low molecular compound having at least a benzene ring, and specific examples include phthalic acid esters and trimellitic acid esters.

  Examples of phthalic acid esters include di-2-ethylhexyl phthalate (DEHP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), di-n-butyl phthalate (DBP), and dimethyl phthalate (DMP). , Butyl benzyl phthalate (BBP), diethyl phthalate (DEP), dicyclohexyl phthalate (DCHP), di-n-heptyl phthalate (DNHP), di-n-octyl phthalate (DNOP), dipropyl phthalate (DPRP) ), Dipentyl phthalate (DPP), dihexyl phthalate (DHP), diisobutyl phthalate (DIBP), and the like.

  Examples of trimellitic acid esters include tri-2-ethylhexyl trimellitic acid (TOTM), trinormal alkyl trimellitic acid, and triisodecyl trimellitic acid.

  Among these, in the analysis method of the present embodiment, diisononyl phthalate (DINP), di-2-ethylhexyl phthalate (DEHP), di-n-butyl phthalate (DBP), and tri-2-ethylhexyl trimellitic acid This is particularly effective for qualitative analysis of (TOTM).

  In addition, the plasticizer contained in the resin sample may be one kind or plural kinds.

  In the present embodiment, the content of the plasticizer contained in the resin sample is preferably 1000 ppm or more found in various legal and regulatory thresholds.

<Extraction solvent>
The extraction solvent used in the analysis method of the present embodiment includes ethanol.

  The content of ethanol contained in the extraction solvent is preferably 50% by volume or more with respect to 100% by volume of the extraction solvent, and when the extraction temperature is increased to 55 ° C., it is 20% by volume or more. Is preferred. Further, the extraction solvent may be ethanol (ethanol 100% by volume).

  The extraction solvent may be a solvent containing ethanol, and may contain other solvents that are compatible with ethanol (such as aromatic solvents are not included in the molecular structure) such as polar solvents such as water and organic solvents. .

  Specific examples of the solvent other than ethanol that may be contained in the extraction solvent include polypropylene glycol and polyoxyether. In consideration of the influence on analysis results and volatility, and from the viewpoint of easy handling at production sites that do not have special chemical analysis equipment, the extraction solvent should be ethanol alone or ethanol and water. It is preferable to use an ethanol solution containing.

  When the extraction solvent is an ethanol solution containing ethanol and water, the ethanol concentration in the ethanol solution is preferably 20% to 100%, more preferably 50% to 100%, and particularly preferably 80% to 100%. preferable.

<TLC plate>
The TLC plate has a structure in which a stationary phase is laminated on a support.

  The support used for TLC is not particularly limited. The support used for TLC is, for example, a glass plate, an aluminum sheet, a plastic sheet, or the like.

  The stationary phase used for TLC is not particularly limited. The stationary phase used for TLC is, for example, silica gel, silica gel-calcium sulfate, silica gel-sodium borate, silica gel-silver nitrate, hydrophobic silica gel, alumina, cellulose, agarose, various chemically modified carriers, and the like. Among these, it is preferable to use silica gel for the stationary phase for separating the plasticizer in the present embodiment.

<Developing solvent>
The developing solvent used for TLC is not limited.

  For example, the developing solvent is a mixture solvent of acetone and n-hexane 1: 4 (volume ratio, the same applies hereinafter), a mixture solvent of acetone: n-hexane 1: 6, a mixture of acetone: n-hexane 1: 9 Solvent, 100% acetone, 1 to 30 mixed solvent of acetone and n-hexane, 50 to 1 mixed solvent of acetone and n-hexane, 8 to 2 mixed solvent of acetonitrile, acetonitrile and water, ethanol, ethanol and acetone 2: 1 mixed solvent, methanol, 9: 1 mixed solvent of methanol and water, 1: 1 mixed solvent of methanol and water, 6: 1 mixed solvent of IPA (isopropyl alcohol) and ethanol, IPA and ethanol 3: 1 mixed solvent, acetic acid, 1 to 6 mixed solvent of acetic acid and ethanol, and the like.

  The developing solvent may be appropriately selected according to the type of plasticizer to be analyzed and the composition of the extraction solvent.

  Among the above, from the viewpoint of ease of separation when developing each of these types of plasticizers when the resin sample contains a plurality of types of plasticizers, acetonitrile, IPA (isopropyl alcohol) are used as developing solvents. It is preferable to use a 6: 1 mixed solvent of ethanol and ethanol, a 3: 1 mixed solvent of IPA and ethanol, acetic acid, or a 1: 6 mixed solvent of acetic acid and ethanol. Among these, it is particularly preferable to use acetonitrile as a developing solvent.

<Analysis process>
Next, the flow of an analysis method using TLC in the present embodiment will be described.

―Dissolution process―
First, a resin sample is pulverized and immersed in an extraction solvent containing ethanol in the present embodiment. Although the finer the degree of pulverization, the plasticizer can be eluted without pulverization until a powder is obtained using a mill or the like. For example, when the elution target is a main component, the resin sample may be pulverized to a size of about several cm.

  Next, the plasticizer contained in the resin sample is dissolved in the extraction solvent by stirring the immersion solution in which the resin sample is immersed in the extraction solvent.

  At this time, it is preferable to heat the immersion solution in which the resin sample is immersed in the extraction solvent at a temperature lower than the boiling point of the extraction solvent. For example, when ethanol is used as the extraction solvent, heating is performed at 50 ° C. Although the heating time depends on the type of plasticizer to be analyzed, for example, the plasticizer to be analyzed contained in the resin sample is di-n-butyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP). ), Diisononyl phthalate (DINP), trimellitic acid tri-2-ethylhexyl (TOTM) and the like as main components, it is 1 hour to 3 hours. Further, when the content of these plasticizers in the resin sample is several percent or less, the maximum is 60 hours.

  Next, the immersion solution is preferably concentrated. For example, the concentration may be performed by putting the immersion solution in a watch glass, an aluminum dish, an aluminum cup or the like, and evaporating only the immersion solution at room temperature with these containers inclined.

―Development process―
A developing solvent is placed in a glass development layer so that the depth is 5 to 7 mm, the lid is covered and left for several hours to equilibrate the vapor in the layer.

  Then, the immersion solution is spotted (spotted) on a TLC plate using a capillary tube or a microsyringe. Then, the spotted TLC plate is put in a developing layer and left until the developing solvent reaches about 3 mm from the upper end of the TLC plate (that is, developed).

―Confirmation process―
After the developed TLC plate is dried, an ultraviolet ray having a central wavelength of 254 nm is irradiated, and a portion that absorbs this light (darkens like a spot on the plate) is confirmed. This position is a position where a substance having an aromatic molecular structure exists. By comparing the Rf value of the spot on the plate with the Rf value of the standard substance, the type of plasticizer is qualitatively determined. This qualifies the plasticizer contained in the resin material.

  As described above, in the analysis method of the present embodiment, the extraction solvent for thin layer chromatography of a resin sample containing at least a low molecular compound having a benzene ring as a plasticizer contains ethanol.

  By using an extraction solvent containing ethanol, the plasticizer contained in the resin sample can be selectively dissolved in the extraction solvent. For this reason, it is possible to easily qualify the plasticizer contained in the resin sample by performing qualitative analysis by TLC using the extraction solvent in which the plasticizer is selectively dissolved.

  Therefore, in the analysis method of this embodiment, the plasticizer contained in the resin sample can be easily qualitatively analyzed.

  In addition, when the plasticizer component of interest is a very small amount of the extracted component when spotted (spotted) on the TLC plate, concentration may be further performed when the TLC plate is spotted. Specifically, a 1 mm spot or a constant scale of a microcapillary is always dropped on the plate several times to several dozen times and concentrated.

  In addition, it is also possible to apply the immersion solution which immersed the resin sample in the extraction solvent of this Embodiment to a well-known analysis method. For example, the plasticizer may be analyzed by FT-IR (Fourier transform infrared spectroscopy) or gas chromatograph mass spectrometry (GC-MS) using the immersion solution in the present embodiment.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the following, “%” is based on mass unless otherwise specified.

<Preparation of extraction solvent>
The following extraction solvents were prepared as extraction solvents.
-Extraction solvent 1: Ethanol-Extraction solvent 2: Mixture of ethanol and water-Comparative solvent 1: Methanol

<Preparation of developing solvent>
The following developing solvents were prepared as developing solvents.
・ Developing solvent 1: acetonitrile

<TLC plate>
-Plate 1 for TLC: As plate 1, Kelselgel 60F254 manufactured by Merck & Co., Inc. was prepared. This plate 1 is a plate for normal phase chromatography using a highly polar column (stationary phase).
-Plate 2 for TLC: As the plate 2, RP-18 F254S manufactured by Merck & Co., Inc. was prepared. This plate 2 is a plate for reverse phase chromatography using a low polarity column (stationary phase).

<Preparation of resin sample>
The following resin samples were prepared as resin samples.
Resin sample 1: The kind and content of the plasticizer contained in resin sample 1 are TOTM, DBP (content 37 ppm in the resin sample), DEHP (content 34000 ppm in the resin sample), DINP (content 140 ppm in the resin sample) )Met. Moreover, the kind of resin contained in the resin sample 1 was PVC (polyvinyl chloride).
Resin sample 2: The type and content of the plasticizer contained in the resin sample 2 are TOTM, DBP (content 85 ppm in the resin sample), DEHP (content 250 ppm in the resin sample), DINP (content 30 ppm in the resin sample) Less). Moreover, the kind of resin contained in the resin sample 2 was PVC (polyvinyl chloride).
Resin sample 3: The type and content of the plasticizer contained in the resin sample 3 are TOTM, DBP (content 150 ppm in the resin sample), DEHP (content 220 ppm in the resin sample), DINP (content 30 ppm in the resin sample) Less). Moreover, the kind of resin contained in the resin sample 3 was PVC (polyvinyl chloride).
-Resin sample 4: The kind and content of the plasticizer contained in the resin sample 4 were TOTM and DEHP (content 200 ppm in the resin sample). Moreover, the kind of resin contained in the resin sample 4 was PVC (polyvinyl chloride).

[Example 1]
In this example, the resin sample 1, the extraction solvent 1, and the developing solvent 1 were used, and qualitative analysis was performed by thin layer chromatography using the prepared TLC plate 2.

  First, the resin sample 1 was pulverized and immersed in the extraction solvent 1. The resin sample was pulverized with scissors so that the length was 1 mm or less.

  Then, an immersion solution in which the pulverized resin sample 1 is immersed in the extraction solvent 1 is put into a 6 mL screw tube bottle, stoppered, stirred for 1 to 2 minutes, put in an oven, and less than the boiling point of the extraction solvent 1 The mixture was heated at 50 ° C. for 60 hours.

  Next, the heated immersion solution was concentrated by substantially evaporating the solvent component at room temperature.

  Next, the developing solvent 1 was put in a 300 cc beaker so as to have a depth of 5 mm, and the lid was covered and left for 1 hour to equilibrate the vapor in the layer.

  And the immersion solution in a present Example was spotted (spot) on the plate 2 for TLC using the micro syringe. The spotted TLC plate 2 was placed in a developing layer and left until the developing solvent reached about 1 cm from the upper end of the TLC plate 2, that is, developed. The developed TLC plate 2 was irradiated with UV (254 nm).

-Evaluation results-
When the development time was 15 minutes, the Rf value of the developed TLC plate 2 was compared with the Rf value of a separately prepared standard material, and when the type of plasticizer was qualitatively, DEHP was confirmed.

  For this reason, in Example 1, it was confirmed that DEHP among all kinds of plasticizers contained in the resin sample 1 can be easily and satisfactorily qualitatively using TLC.

[Example 2]
Development was performed in the same manner as in Example 1 except that the resin sample 2 was used instead of the resin sample 1.
-Evaluation results-
By comparing the Rf value of the developed TLC plate 2 with the Rf value of a separately prepared standard material at the stage of 15 minutes of development time, the type of plasticizer was qualitatively determined. It could be confirmed.

  For this reason, in Example 2, it was confirmed that TOTM and DBP among all kinds of plasticizers contained in the resin sample 2 can be easily and satisfactorily qualitatively using TLC.

[Example 3]
Development was performed in the same manner as in Example 1 except that the resin sample 3 was used instead of the resin sample 1.

-Evaluation results-
When the Rf value in the developed TLC plate 2 was compared with the Rf value of the separately prepared standard material at the stage of 15 minutes of development time, the type of plasticizer was qualitatively determined. TOTM and DINP were It could be confirmed.

  For this reason, in Example 3, it was confirmed that TOTM and DINP among all types of plasticizers contained in the resin sample 3 can be easily and satisfactorily qualitatively using TLC.

[Example 4]
Development was performed in the same manner as in Example 1 except that the resin sample 4 was used instead of the resin sample 1.

-Evaluation results-
When the Rf value in the developed TLC plate 2 was compared with the Rf value of a separately prepared standard material at the stage of 15 minutes of development time, the type of plasticizer was qualitatively confirmed, and TOTM was confirmed.

  For this reason, in Example 4, it was confirmed that TOTM among all types of plasticizers contained in the resin sample 4 can be easily and satisfactorily qualitatively using TLC.

[Example 5]
Development was performed in the same manner as in Example 2 except that the extraction solvent 2 was used instead of the extraction solvent 1. As a result, the result shown in FIG. 1 was obtained.

-Evaluation results-
When the Rf value in the developed TLC plate 2 was compared with the Rf value of a separately prepared standard material at the stage of 15 minutes of development time, the type of plasticizer was qualitatively determined. TOTM and DEHP were It could be confirmed.

  For this reason, in Example 5, it was confirmed that TOTM and DEHP among all kinds of plasticizers contained in the resin sample 2 can be easily and satisfactorily qualitatively using TLC.

[Comparative Example 1]
Development was performed under the same conditions as in Example 2, except that Comparative Solvent 1 (methanol) was used instead of Extractive Solvent 1 as the extracting solvent. As a result, the result shown in FIG. 2 was obtained.

-Evaluation results-
At a stage where the development time was 15 minutes, the Rf value in the developed TLC plate 2 was compared with the Rf value of a separately prepared standard material, and the type of plasticizer was qualitatively determined. TOTM and DNOP (phthalic acid Di-n-octyl) was confirmed.

  The resin sample 2 used in this comparative example does not contain DNOP. For this reason, in Comparative Example 1, the plasticizer contained in the resin sample could not be qualitatively favorably using TLC.

Claims (3)

An extraction solvent for thin layer chromatography of a resin sample containing at least a low molecular weight compound having a benzene ring as a plasticizer contains ethanol at 20% by volume or more, and the extraction solvent is heated at a temperature below the boiling point of ethanol. Characteristic analysis method. The analysis method according to claim 1, wherein the developing solvent for thin layer chromatography is acetonitrile. The plasticizer includes at least one of the low molecular weight compounds of diisononyl phthalate, di-2-ethylhexyl phthalate, di-n-butyl phthalate, and tri-2-ethylhexyl trimellitic acid,
The analysis method according to claim 1 or claim 2 .