JP2019197006A - Method for analyzing phthalate esters - Google Patents

Abstract

To provide a quick and easy method for analyzing phthalate esters in an embodiment.SOLUTION: A method for analyzing phthalate esters of an embodiment includes: extracting a plasticizer contained in resin or a rubber material for 30 minutes or more and three hours or less by using acetonitrile as an extraction solvent (S1); and attaching an extract obtained from the extraction to an analysis starting point in a stationary phase and developing the extract in a mobile phase to perform thin-film chromatography analysis (S2).SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a method for analyzing phthalates.

  As environmental issues increase, electrical and electronic products are also required to be environmentally friendly. In 2006, the European Union enforced the Restriction for the use of certain hazardous substances in electrical and electronic equipment (RoHS Directive) on the restriction of the use of six specific hazardous substances contained in electrical and electronic equipment. Thus, in recent years, regulations on chemical substances have become stricter, and as a company that manufactures electrical and electronic equipment, management of chemical substances in constituent materials used in products has become very important.

  The revised RoHS directive applied from July 2019 has determined that four types of phthalates (PAE) used as plasticizers for resin and rubber materials will be added as restricted substances. The threshold is 0.1 wt% (1000 ppm).

  Known screening methods for phthalates include thermal desorption gas chromatography mass spectrometry, ion attachment mass spectrometry, and solvent extraction-gas chromatography mass spectrometry. However, these analyzes require dedicated and expensive equipment and specialized techniques, and it is not easy to analyze a wide variety of electric and electronic devices from the viewpoint of equipment and technology.

Japanese Patent Laid-Open No. 2016-200531

  Embodiments of the present invention provide a quick and simple method for analyzing phthalates.

  In the method for analyzing phthalate esters according to the embodiment, acetonitrile is used as an extraction solvent to extract a plasticizer contained in a resin or rubber material for 30 minutes or more and 3 hours or less, and the extract obtained by the extraction is used as a stationary phase. It includes developing an extract with a mobile phase attached to the starting point of analysis and performing thin layer chromatography analysis.

The figure which shows the procedure of the analysis method in connection with embodiment. The figure which shows the procedure which represented the procedure of FIG. 1 in detail. The table | surface of Rf value of the substitute compound of phthalic acid esters and phthalic acid esters concerning embodiment. The image of the result of thin-layer chromatography analysis of the solution containing the substitute compound of phthalates and phthalates according to the embodiment. The image of the analysis result of Example 1. The image of the analysis result of Example 2. The table | surface of the analysis result of Example 2. FIG. Table of analysis results of thermal desorption gas chromatograph mass spectrometry.

Hereinafter, a preferred embodiment will be described in detail with reference to the drawings.
(First embodiment)
The analysis method of the first embodiment includes a plasticizer extraction procedure (S1) and a thin-layer chromatography analysis procedure S2 from a resin material or a rubber material as shown in the diagram showing the procedure relating to the embodiment of FIG. FIG. 2 is a diagram showing a procedure representing the procedure of FIG. 1 in detail.

  It is preferable that extraction procedure S1 includes extracting the plasticizer contained in a resin material or a rubber material for 30 minutes or more and 3 hours or less using acetonitrile as an extraction solvent (procedure). Further, the thin layer chromatography analysis procedure S2 includes a thin layer chromatography analysis (procedure) in which the extract obtained by the extraction is attached to the analysis starting point of the stationary phase and the extract is developed in the mobile phase. preferable.

  The analysis target is a resin material or a rubber material. In the analysis method of the embodiment, qualitative analysis or qualitative analysis and quantitative analysis of a plasticizer contained in a resin material or a rubber material are performed. In the first embodiment, it may be unclear whether the analysis target is a resin material or a rubber material. The analysis target may include additives such as a lubricant in addition to the plasticizer, resin, and rubber.

  The resin contained in the resin material is not particularly limited, and specific resins contained in the resin material are, for example, polyvinyl chloride, polyethylene, polypropylene, polyester, urethane, vinyl acetate, acrylic resin, epoxy resin, nitrocellulose, etc. is there. The resin material is typically a material in which 50 wt% or more of the sample is resin.

  The rubber contained in the rubber material is not particularly limited. The specific rubber contained in the rubber material is a rubber material such as nitrile butadiene rubber or chloroprene rubber, which is typically a material in which 50 wt% or more of the sample is rubber.

  The analysis of the embodiment can perform a simple screening of a plasticizer in a resin material or a rubber material. The plasticizer of the embodiment is preferably a phthalate ester or a substitute for phthalate esters. In the analysis method of the embodiment, a resin material or a rubber material containing a plasticizer of 0.05 wt% to 50 wt%, 0.7% to 50 wt%, or 0.1 wt% to 50 wt% is an analysis target. .

  Plasticizers contained in resin materials or rubber materials are dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), di-2-ethylhexyl phthalate (DEHP), diisobutyl phthalate (DIBP), diisononyl phthalate (DINP) ), Diisodecyl phthalate (DIDP), di-n-octyl phthalate (DNOP), dicyclohexyl phthalate (DCHP), dimethyl phthalate (DMP), diethyl phthalate (DEP), bis-2-ethylhexyl isophthalate (DOIP) ), Tris-2-ethylhexyl terephthalate (DOTP), tris-2-ethylhexyl trimellitic acid (TOTM) and at least one selected from the group consisting of bis-2-ethylhexyl adipate (DOA).

  Among the plasticizers, dibutyl phthalate, butyl benzyl phthalate, di-2-ethylhexyl phthalate, diisobutyl phthalate, diisononyl phthalate, diisodecyl phthalate, di-n-octyl phthalate, dicyclohexyl phthalate, dimethyl phthalate, Diethyl phthalate, bis-2-ethylhexyl isophthalate and tris-2-ethylhexyl terephthalate are phthalate esters.

  Among these, dibutyl phthalate, butyl benzyl phthalate, di-2-ethylhexyl phthalate and diisobutyl phthalate are regulated substances in the RoHS regulation. The analysis method of the embodiment can quickly and easily analyze whether or not dibutyl phthalate, butyl benzyl phthalate, di-2-ethylhexyl phthalate and diisobutyl phthalate are contained in the resin material or rubber material. . If the regulation conditions are changed, the phthalate esters of the regulated substances in the embodiments also change.

  Trimetic acids and adipic acids are alternative compounds for phthalates. Examples of trimellitic acids include tris-2-ethylhexyl trimellitic acid (TOTM), trinormal alkyl trimellitic acid, triisodecyl trimellitic acid, and the like. Examples of the adipate esters include bis-2-ethylhexyl adipate (DOA), diisononyl adipate, diisodecyl adipate, and the like.

  Note that the regulated amount in the RoHS regulation is 0.1 wt% or more. Therefore, it is preferable as an analysis method of the embodiment to detect regulated phthalates of 0.05 wt% or less than the regulated value and 0.07 wt% or more.

  As the extraction solvent for extracting the plasticizer from the resin material or rubber material, acetonitrile is preferably used. By using acetonitrile as an extraction solvent, extraction capable of being detected by thin layer chromatography analysis can be performed in a relatively short time regardless of whether the analysis target is a resin material or a rubber material. By using acetonitrile as an extraction solvent, the plasticizer can be extracted in a relatively short time of 30 minutes or more and 3 hours or less even when only a small amount of phthalates are contained. A more preferable extraction time is 1 hour or more and 2 hours or less although the conditions such as temperature are affected. Let the solution which the plasticizer eluted in the extraction solvent be an extract.

  Even if it is uncertain whether the analysis object is a resin material or a rubber material, screening can be performed under the same conditions by using acetonitrile as an extraction solvent. There is no problem if the material of the analysis object is clear, but the printed material may not match the actual material. Therefore, it is preferable to use acetonitrile as the extraction solvent from the viewpoint of performing screening more reliably.

  The extraction solvent can contain a solvent other than acetonitrile, but is preferably 100% acetonitrile.

  When a solvent such as ethanol is used as an extraction solvent, it is not preferable because it takes several tens of hours or more to extract a low-concentration plasticizer to a detectable level. Acetone can extract a plasticizer in a short time. However, acetone that dissolves a resin such as polyvinyl chloride is not preferable as an extraction solvent. In addition, toluene and hexane do not dissolve the resin and rubber, but are not suitable for extraction in a short time because the extraction rate of the plasticizer is low. Isopropanol can also be extracted in a short time to such an extent that a low-concentration plasticizer can be detected.

  It is preferable to extract from a small resin material or rubber material. It is preferable that the longest side of the resin material or rubber material is chopped or crushed so as to be 4 mm or less. Since extraction efficiency is poor when extracted from a large member, it is preferable to extract from a small member.

  The volume (mL) of the extraction solvent relative to the mass (mg) of the resin or rubber material when the resin material or rubber material is extracted with the extraction solvent [volume of extraction solvent (mL)] / [resin material or rubber material The mass (mg)] is preferably 1/250 mL / mg or more and 1/1000 mL / mg or less. [Volume of extraction solvent (mL)] / [mass of resin material or rubber material (mg)] is more preferably 1/500. In extraction, the extraction time can be shortened by heating. In addition, it is preferable to perform extraction in an airtight container. Further, it is preferable that the resin material or the rubber material is immersed in the extraction solvent and that the extraction solvent is not excessive. If a large amount of extraction solvent is used, the plasticizer concentration in the extraction solvent will be relatively low. By reducing the amount of the extraction solvent to be used, the plasticizer concentration of the extract can be increased to such an extent that thin layer chromatography analysis can be performed as it is without concentrating the solvent after extraction.

  In the extraction, the extraction solvent temperature is preferably 40 ° C to 70 ° C. The extraction speed can be increased by increasing the temperature of the extraction solvent. Moreover, it is preferable to perform ultrasonic irradiation during extraction. Extraction speed can also be increased by ultrasonic irradiation. The extraction is preferably performed in a closed container. It is preferable in that the solvent can be prevented from volatilizing and the plasticizer can be quantitatively analyzed.

  Under this extraction condition, an error due to extraction is small (RSD 10% or less), so that a highly reliable analysis can be performed.

  In the thin layer chromatography analysis of the embodiment, it is preferable to use a plate for reverse phase chromatography (reverse phase plate) using a column (stationary phase) with low polarity. Plasticizers can be analyzed on plates for normal phase chromatography using a column with a high polarity (stationary phase), but in the analysis of phthalates, the accuracy of analysis can be improved by using reversed-phase plates. it can.

The reverse phase plate is preferably a plate in which a stationary phase such as silica gel is laminated on a support. Examples of the support include glass, an aluminum sheet, and a plastic sheet. The silica gel is preferably chemically modified. Examples of chemical modification to silica gel include an octadecyl group (C18), an octyl group (C8), and a dimethylsilyl group (Si (CH ₃ ) ₂ ). As a chemical modification to silica gel, the octadecyl group (C18) is preferable in the analysis of phthalates using acetonitrile as a mobile phase.

  Hereinafter, the analysis method will be described with reference to the diagram illustrating the procedure of FIG. In the diagram showing the procedure of FIG. 2, the plasticizer from the resin material or the rubber material is extracted (procedure) (S1), the extraction liquid is spotted to the stationary phase (procedure) (S2A), and the mobile phase is extracted. Develop liquid (S2B), measure Rf value of each spot (S2C), determine plasticizer type from Rf value (procedure) (S2D), and match Rf value of phthalates If not, the analysis is terminated (S2E), or if it matches the Rf value of phthalates, a flow of concentration analysis or precise analysis (S2F) is described. Concentration analysis and precise analysis can be omitted in the analysis method of the embodiment.

  Hereinafter, the procedure after S2A, which is a thin layer chromatography analysis procedure, will be described. First, the extract obtained by extraction is spotted (S2A) on the stationary phase (reverse phase plate), and the extract is attached to the analysis starting point of the stationary phase. In order to be able to detect a low-concentration plasticizer in the resin material or rubber material, it is preferable to spot a small amount of the extract multiple times. For example, it is preferable that the spotting capacity is 0.5 μL or more and 1.5 μL or less, and the process is performed 5 to 10 times. For spotting, a capillary tube or a pipetter is used. To give a specific example, if the extraction liquid is a plastic material extracted from a resin material or rubber material containing 0.07 wt% of regulated phthalates, 1 μL is spotted 5 times by thin layer chromatography analysis. Can be detected. Therefore, it is preferable to spot 1 μL five times or more. When the plasticizer concentration is high, it is also preferable to perform analysis by diluting the extract or reducing the number of spottings.

  The starting point for analysis, which is a spot for spotting, is preferably separated from the lower end of the stationary phase by, for example, about 1 cm to 2 cm. The development distance by the mobile phase is preferably 7 cm or more for the analysis of phthalates. Therefore, the distance from the upper end of the stationary phase to the analysis starting point is preferably longer than 7 cm. The longer the development distance, the easier the analysis, but the longer the analysis time. Therefore, the development distance is preferably 7 cm to 25 cm, 7 cm to 20 cm, and 7 cm to 17 cm. Since the size of a commercially available plate is 10 cm or 20 cm, the development distance is preferably 7 cm or 17 cm. Since the separation is difficult when the development distance is short, the development distance is preferably 17 cm.

  Next, the extract is developed (S2B) in the mobile phase. Specifically, the lower end of the stationary phase (reverse phase plate) to which the extract is attached by spotting the extract at the analysis starting point is immersed in a developing solvent as a mobile phase. Then, the extract develops and spots appear by the mobile phase. When the extract is developed, it is preferable to carry out in a space containing a developing solvent as a mobile phase and filled with the vapor of the developing solvent. Acetonitrile is preferably used as the mobile phase. Acetonitrile may contain additives for adjusting ph. By using the same acetonitrile for the extraction solvent and the developing solvent, the use of one solvent for the analysis improves the convenience of the analysis and is also preferable from the viewpoint of the treatment of the waste liquid.

  Next, the Rf value of each spot is measured (S2C). When the movement distance of the mobile phase from the analysis starting point is B and the distance from the analysis starting point to the spot generated by the development of the extract is A, the Rf value is obtained from A / B. First, the stationary phase (reverse phase plate) that has been immersed in the developing solvent as the mobile phase is taken out, and the position where the developing solvent is raised is marked. The mark is, for example, a straight line indicating the position where the developing solvent is raised. The distance between the mark placed at the position where the developing solvent is raised and the analysis starting point is the moving distance B of the mobile phase from the analysis starting point. Next, a spot that emits fluorescence is marked by irradiating with a UV lamp (wavelength 254 nm). The distance from the mark of the spot to the starting point of the analysis is the distance A to the spot generated by the development of the extract from the starting point of the analysis.

  The Rf value is a value unique to the substance. FIG. 3 shows a table of Rf values of phthalates and alternative compounds of phthalates. FIG. 4 is an image showing the result of thin layer chromatography analysis of a solution containing phthalates and a substitute compound of phthalates. Although there are phthalate esters whose Rf values are close and difficult to identify, the possibility of containing phthalate esters subject to regulation can be determined by the analysis method of the embodiment. The resulting image in FIG. 4 has a development distance of 17 cm. When the development distance is 17 cm, di-2-ethylhexyl phthalate (DEHP) and di-n-octyl phthalate (DNOP) having a close Rf value can be separated.

Next, the type of plasticizer is determined from the Rf value obtained from each spot (S2D). More specifically, it is determined whether or not the plasticizer contains at least one selected from the group consisting of dibutyl phthalate, butyl benzyl phthalate, di-2-ethylhexyl phthalate, and diisobutyl phthalate. The Rf value of each compound shown in FIG. 3 is compared with the Rf value obtained from each spot. The Rf value of regulated shown in FIG. 3 and Rf _n, when the Rf value obtained from the spot satisfies the following 0.93Rf _n or 1.03Rf _n, regulated and Rf value obtained from the spot of phthalates It is determined that the Rf values (Rf _n ) match. That is, the Rf value obtained from the spot allows an error of ± 3%. For example, the Rf value of the spot is 0.41 to 0.43 (bis (2-ethylhexyl) phthalate), 0.78 to 0.82 (butylbenzyl phthalate), 0.73 to 0.77 When it is (dibutyl phthalate) and 0.74 or more and 0.78 or less (diisobutyl phthalate), it is determined that the plasticizer is a regulated phthalate ester. As a quick and simple analytical method, it is sufficient if screening can be performed to determine whether the plasticizer is a regulated phthalate ester. The Rf values of the plasticizers shown in the table of FIG. 3 are the regulated phthalates (bis (2-ethylhexyl (0.41 to 0.43)) phthalate, butyl benzyl phthalate), even if errors are taken into account. (0.78 or more and 0.82 or less), dibutyl phthalate (0.73 or more and 0.77 or less), diisobutyl phthalate (0.74 or more and 0.78 or less)) and non-regulated plasticizer (diisononyl phthalate) (0.32 or more and 0.34 or less), diisodecyl phthalate (0.26 or more and 0.28 or less), di-n-octyl phthalate (0.36 or more and 0.38 or less), dicyclohexyl phthalate (0.60) 0.64 or less), dimethyl phthalate (0.86 or more and 0.92 or less), diethyl phthalate (0.83 or more and 0.89 or less), bis-2-ethylhexyl isophthalate (0.27 or more and 0.002 or less). 9 or less), tris-2-ethylhexyl terephthalate (0.26 or more and 0.28 or less), and tristrimethyl acid tris (2-ethylhexyl) (0.17 or more and 0.19 or less)). . Therefore, practical phthalate esters and alternative materials can be screened by a quick and simple analysis method called thin layer chromatography analysis. In addition, concentration analysis can be performed using this result, and precise analysis by thermal desorption gas chromatography mass spectrometry, ion attachment mass spectrometry, solvent extraction-gas chromatography mass spectrometry, or the like can be performed.

Further, Rf value obtained from the spot when not satisfy the following 0.97Rf _n or 1.03Rf _n, Rf value phthalates regulated with Rf value obtained from the spot (Rf _n) does not match judge. That is, it is determined that the regulated phthalates are not included in the analyzed resin material or rubber material, and the analysis is terminated (S2E).

When it is determined that the Rf value obtained from the spot matches the Rf value (Rf _n ) of the phthalates, the concentration analysis or precise analysis of the phthalates (S2F) from the results of thin-layer chromatography analysis It can be performed. The S2F analysis procedure is an arbitrary analysis procedure as described above, and can be omitted as a quick and simple analysis method.

  The Rf value of each spot can be obtained by visually observing an image taken by irradiating a UV lamp or by image processing software. An example of the image processing software is Just TLC. In addition, when conducting concentration analysis from thin layer chromatography analysis, thin layer chromatography analysis is performed under the same conditions in a thin layer chromatography analysis using a standard solution containing phthalates of a specific concentration as a standard.

  Density analysis is performed using image processing software. The compound concentration of each spot can be determined by analyzing an image taken by irradiating a UV lamp with image processing software. Examples of precise analysis include thermal desorption gas chromatograph mass spectrometry and ion attachment mass spectrometry.

  If a series of analysis conditions including the processing of the sample are unified, the type of plasticizer can be determined from the distance A to the spot generated by the development of the extract from the analysis starting point.

  According to this embodiment, even if it is not specified whether the sample is a resin material or a rubber material, analysis of phthalates can be performed quickly and easily. The analysis method can be applied from a concentration lower than the lower limit of the regulated amount to a very high concentration, and is preferable as a primary screening method for a wide variety of products. For example, the analysis method of the embodiment is excellent in terms of reliability because the analysis of phthalates can be performed even when the sample is a rubber material despite the notation of PVC. Thin layer chromatography analysis is preferable as a primary screening in which inspection of all samples is required because a large number of uses can be analyzed simultaneously. The analysis method according to the embodiment is preferable as a primary screening method for a wide variety of products in that an expensive apparatus and advanced technology are not required. The rapid and simple analysis of the embodiment can prevent the distribution of products containing regulated phthalates.

(Second Embodiment)
The second embodiment is a modification of the analysis method of the first embodiment. The second embodiment is different from the first embodiment in that the sample to be analyzed is known to be a rubber material, and the type of extraction solvent and the extraction time are different. Except as described below, the first embodiment and the second embodiment are common. Description of common contents is omitted.

  As the extraction solvent of the second embodiment, it is preferable to use ethyl acetate or isopropanol. When using ethyl acetate as the extraction solvent, the extraction time is preferably 3 minutes or more and 10 minutes or less, or 3 minutes or more and 5 minutes or less. Since ethyl acetate is easily absorbed by the rubber material, it is not preferable to extract it for a long time. Since ethyl acetate can extract a plasticizer in a very short time, it can be performed more quickly than the analysis of the first embodiment. When used as an extraction solvent for isopropanol, the extraction time is preferably from 1 hour to 3 hours.

  According to this embodiment, when the sample is specified as a rubber material, analysis of phthalates can be performed quickly and easily. The analysis method can be applied from a concentration lower than the lower limit of the regulated amount to a very high concentration, and is preferable as a primary screening method for a wide variety of products. The analysis method according to the embodiment is preferable as a primary screening method for a wide variety of products in that an expensive apparatus and advanced technology are not required. When ethyl acetate is used as the extraction solvent, the analysis time can be further shortened. The rapid and simple analysis of the embodiment can prevent the distribution of products containing regulated phthalates.

Hereinafter, the analysis method of the present embodiment will be described in more detail by way of examples.
(Example 1)
Example 1 is an experiment in which thin-layer chromatography analysis was performed to determine whether or not low-level regulated phthalates can be detected using samples (samples A to G) whose types and concentrations of plasticizer are known in advance. It is. Sample A is a commercially available standard sample (SPEX). Samples B and E are polyvinyl chloride (resin material) containing a plasticizer prepared for the examples. Samples C and F are nitrile rubbers (rubber materials) containing a plasticizer prepared for the examples. Samples D and G are chloroprene rubbers containing a plasticizer prepared for the examples. Seven samples were chopped with scissors so that the long side was 4 mm or less, and each 250 mg was weighed and placed in a separate 2 mL crimp vial. Then, 0.5 mL of acetonitrile is added to the crimp vial as an extraction solvent, and the lid is sealed. And the plasticizer contained in a sample was extracted, performing an ultrasonic irradiation at 60 degreeC, and the extract was obtained. The extraction time for samples A to D is 1 hour. The extraction time for samples EG is 2 hours. The obtained extract was spotted 5 times at a time of 1 μL onto a 20 cm × 20 cm Merck RP-18F254s (reverse phase plate). Spotting was performed so that the starting point of analysis was 2 cm from the lower end of the reversed phase plate.

  Acetonitrile is added in advance to a container that can accommodate a 20 cm × 20 cm plate, and the container is filled with vaporized acetonitrile. At this time, the liquid level height of acetonitrile was about 1 cm. Place the spotted reversed-phase plate in the container so that the lower end of the spotted reversed-phase plate is immersed in acetonitrile, and when the development distance (the height of acetonitrile from the starting point of analysis as the spotting point) is 17 cm, remove from the container. The reverse phase plate was removed.

  The reverse phase plate taken out was irradiated with a 254 nm UV lamp and photographed with a digital camera under non-flash conditions. The captured images were analyzed with Just TLC, a thin layer chromatography analysis software. FIG. 5 shows an image of the analysis result of Example 1. The analysis result image of Example 1 shown in FIG. 5 is an image after analysis by Just TLC. The image shown in FIG. 5 was close to the result of visual observation after irradiation with a UV lamp. The Rf value of each spot of each sample was obtained by visual observation and image processing software, and the type of plasticizer contained in the sample was examined. The type of plasticizer found from the Rf value in Example 1 was consistent with the type of plasticizer known in advance. Similar results were obtained both visually and by software analysis. The plasticizer concentration at each spot was analyzed using Just TLC. At this time, using the sample A as a standard, the plasticizer concentrations of the samples B to G could be obtained.

(Example 2)
Seven samples (samples H to N) whose type of plasticizer was unclear whether the sample was a resin material or a rubber material were subjected to thin layer chromatography analysis in the same manner as in Example 1. FIG. 6 shows an image of the analysis result of Example 2. The analysis result image of Example 2 shown in FIG. 6 is an image after analysis by Just TLC. The analysis result of Example 2 is shown in the table of FIG. The table in FIG. 7 shows the results of image analysis. In FIG. 7, the evaluation when the spot was confirmed was set as “◯”, the evaluation when the spot was suspected was set as “Δ”, and the evaluation when the spot was not confirmed was left blank.

  The sample analyzed in Example 2 is not only uncertain whether it is a resin material or a rubber material, and the type of plasticizer contained is unknown. Therefore, in order to evaluate the screening result by thin layer chromatography analysis, the sample analyzed in Example 2 was subjected to precise analysis by thermal desorption gas chromatography mass spectrometry. The table of FIG. 8 shows the analysis results of thermal desorption gas chromatograph mass spectrometry. In FIG. 8, the evaluation when inclusion was recognized was rated as “◯”, and the evaluation when the content was below the detection limit was blank.

  Comparing the tables of FIG. 7 and FIG. 8, it can be seen that all the regulated phthalates were correctly detected by thin film chromatography analysis. In thermal desorption gas chromatograph mass spectrometry, it is possible to determine the types of plasticizers having similar Rf values in thin layer chromatographic analysis.

  Example 1 is a preliminary experiment for examining whether the analysis method of the present embodiment can identify the type of low-concentration plasticizer. Even if the sample is unknown whether it is a resin material or a rubber material, it is about the regulated value. This shows that phthalates can be detected. Since visual inspection and analysis by image processing software can be performed quickly and easily, Example 1 shows that the analysis method of the embodiment is highly reliable as primary screening.

  In Example 2, when an unknown sample was analyzed for the type and concentration of the plasticizer, it was examined whether or not phthalate esters could be analyzed, and phthalate esters subject to regulation were detected without omission. As a result, the thin layer chromatography analysis of the embodiment was shown to be a reliable primary screening method.

  Also, the analysis method of the embodiment is a reliable screening method in that the type and concentration of the plasticizer can be analyzed by performing image analysis even when the image is developed in a linear form instead of a spot. Is shown.

Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

Claims (9)

Using acetonitrile as an extraction solvent, extracting the plasticizer contained in the resin or rubber material for 30 minutes to 3 hours;
A method for analyzing phthalates, comprising: attaching an extract obtained by the extraction to an analysis starting point of a stationary phase, developing the extract with a mobile phase, and performing thin layer chromatography analysis. Using ethyl acetate as an extraction solvent, extracting a plasticizer contained in a rubber material for 3 minutes to 10 minutes, or isopropanol as an extraction solvent, and extracting the plasticizer for 1 hour to 3 hours;
A method for analyzing phthalic acid esters, comprising thin layer chromatography analysis in which the extract obtained by the extraction is attached to an analysis starting point of a stationary phase and the extract is developed in a mobile phase.   The method for analyzing phthalates according to claim 1 or 2, wherein in the analysis by the thin layer chromatography, a plate for reverse phase chromatography using the stationary phase is used and acetonitrile is used as the mobile phase.   The plasticizer is dibutyl phthalate, butyl benzyl phthalate, di-2-ethylhexyl phthalate, diisobutyl phthalate, diisononyl phthalate, diisodecyl phthalate, di-n-octyl phthalate, dicyclohexyl phthalate, dimethyl phthalate, 2. One or more selected from the group consisting of diethyl phthalate, bis-2-ethylhexyl isophthalate, tris-2-ethylhexyl terephthalate, tris-2-ethylhexyl trimellitic acid and bis-2-ethylhexyl adipate 4. The method for analyzing phthalates according to any one of items 1 to 3.   The phthalate ester analysis method according to any one of claims 1 to 4, wherein the plasticizer is contained in a resin material or a rubber material in an amount of 0.05 wt% to 50 wt%.   The method for analyzing phthalates according to any one of claims 1 to 5, wherein the extract of 0.5 µL or more and 1.5 µL or less is attached to the analysis starting point 5 to 10 times.   In the analysis by the thin layer chromatography, when the moving distance of the mobile phase from the starting point of analysis is B and the distance to the spot generated by the development of the extract from the starting point of analysis is A, Rf The method for analyzing a phthalate ester according to any one of claims 1 to 6, wherein the kind of plasticizer in the extract is analyzed from A / B as a value.   The method according to any one of claims 1 to 7, wherein it is determined whether or not the plasticizer includes one or more selected from the group consisting of dibutyl phthalate, butyl benzyl phthalate, di-2-ethylhexyl phthalate, and diisobutyl phthalate. The analysis method of phthalates as described in the paragraph.   The method for analyzing phthalates according to claim 7, wherein the Rf value is obtained by visual observation or image processing software.