Determination of dioctyl sebacate content in polyvinyl acetate

Abstract

The present invention discloses a method for determining the content of diethyl hexyl sebacate in polyvinyl acetate. The method comprises the following steps: (1) adding a dissolving solvent to a pretreated polyvinyl acetate sample, and after the sample is completely dissolved, adding a main precipitant dropwise to the solution until no polymer continues to precipitate, then adding a co-precipitant dropwise until the precipitation is complete, and constant volume with the co-precipitant as a test solution, wherein the co-precipitant is selected from one of isopropanol, water and heptane; (2) preparing a standard working solution; (3) performing gas chromatography-mass spectrometry analysis on the standard working solution and the test solution. The assay method proposed by the present invention can meet higher detection requirements, such as reducing the detection limit, and the method also has the advantages of being simple to operate and fast, and has a very wide range of application prospects.

Description

Technical field:

[0001] The invention relates to the technical field of food analysis, and in particular to a method for determining the content of diisooctyl sebacate in polyvinyl acetate. Background technology:

[0002] There are currently no reports on the detection technology for the content of diisooctyl sebacate in polyvinyl acetate at home and abroad. Diisooctyl sebacate is often used in combination with phthalates and is a low-temperature resistant plasticizer used in a variety of plastic resins. Existing reports mainly focus on the detection of the synthesis process and product performance indicators of this substance. There are no reports on the analytical detection methods or relevant standards for this substance, and it is impossible to meet the increasingly stringent regulations or health standards. The current extraction method for plasticizers is the solvent extraction-GC / MS method, which uses Soxhlet extraction, accelerated solvent extraction, microwave extraction and other methods to extract the plasticizer in the plastic into an organic solvent, and then conducts GC / MS determination after treatment with suitable purification methods. However, these methods have shortcomings such as long extraction time, low efficiency, and easy contamination of the chromatography-mass spectrometry system. This problem needs to be solved urgently. Summary of the invention:

[0003] In order to solve the problems existing in the prior art, the present invention proposes a method for determining the content of diisooctyl sebacate in polyvinyl acetate. The method comprises the following steps: dropwise adding a main precipitant to precipitate polymer molecules, then using an auxiliary precipitant to thoroughly remove the polymer, and finally using GC-MS to determine the content of diisooctyl sebacate in polyvinyl acetate. The method has low interference, high sensitivity, solvent saving, and high analysis efficiency.

[0004] The object of the present invention is to provide a method for determining the content of diethyl hexyl sebacate in polyvinyl acetate, comprising the steps of:

[0005] (1) Preparation of test solution: Add a dissolving solvent to the pretreated polyvinyl acetate sample, and after the sample is completely dissolved, obtain a solution with a sample mass concentration of 0.1-0.3 g / mL, add a main precipitant dropwise to the solution until no polymer continues to precipitate, then add an auxiliary precipitant dropwise until precipitation is complete, and adjust the volume with the auxiliary precipitant to obtain the test solution, wherein the auxiliary precipitant is selected from one of isopropyl alcohol, water, and heptane;

[0006] (2) Preparation of standard working solution:

[0007] Preparation of dioctyl sebacate stock solution: Accurately weigh 10 mg of dioctyl sebacate standard into a 10 mL volumetric flask and dilute to the mark with methanol to obtain a stock solution with a concentration of 1000 mg / L.

[0008] Preparation of dioctyl sebacate standard intermediate solution: Pipette 0.1 mL of dioctyl sebacate stock solution into a 10 mL volumetric flask and dilute to the mark with a 1:1 volume ratio of methanol to isopropanol to obtain a 10 mg / L standard intermediate solution.

[0009] Preparation of standard working solutions: Accurately pipette a 10 mg / L dioctyl sebacate standard intermediate solution and dilute it step by step to prepare standard working solutions with concentrations of 0.1 mg / L, 0.2 mg / L, 0.5 mg / L, 1.0 mg / L, and 2.0 mg / L.

[0010] (3) Gas chromatography-mass spectrometry: The standard working solution and the test solution were analyzed by gas chromatography-mass spectrometry.

[0011] The dissolution-precipitation method not only completely extracts the plasticizer by dissolving the plastic, but also removes the polymer through precipitation, protecting the chromatography-mass spectrometry system from contamination. The present invention aims to establish a "dissolution-primary precipitation-auxiliary precipitation" method based on the conventional "dissolution-precipitation" method. The method precipitates the polymer molecules by dropwise addition of an excess primary precipitant, then thoroughly removes the polymer using an auxiliary precipitant. Finally, GC-MS is used to determine the content of dioctyl sebacate in polyvinyl acetate. This method has low interference, high sensitivity, solvent conservation, and high analytical efficiency, capable of detecting the compound at a level of 0.25 mg / kg.

[0012] Preferably, the dissolving solvent in step (1) is selected from one of benzene, acetone and chloroform.

[0013] Preferably, the main precipitant in step (1) is selected from one of methanol, n-hexane and petroleum ether.

[0014] More preferably, in step (1), the volume ratio of the main precipitant to the dissolving solvent is 0.5-1.0:1, and the volume ratio of the auxiliary precipitant to the dissolving solvent is 0.3:1.0.

[0015] More preferably, in step (1), the main precipitant is methanol and the auxiliary precipitant is isopropanol.

[0016] Preferably, the pretreatment step of the polyvinyl acetate sample pretreated in step (1) is: cutting the polyvinyl acetate sample into small pieces with scissors, placing the pieces into a freeze-crushing container, and freeze-crushing the sample with liquid nitrogen until the sample is crushed into a powdery solid with a particle size of 100 to 200 μm.

[0017] Preferably, the volume is fixed with a precipitant in step (1), and the specific steps of preparing the test solution are as follows: fixing the volume with a co-solvent, shaking the fixed solution thoroughly and letting it stand, taking 5 mL of the supernatant, concentrating it to 1 mL with nitrogen blowing, and filtering it with an organic filter membrane to obtain a test solution for gas chromatography-mass spectrometry analysis.

[0018] Preferably, the operating parameters of the gas chromatography-mass spectrometry in step (3) are:

[0019] Chromatographic conditions: HP-5MS capillary column, 30 m × 0.25 mm, 0.25 μm; temperature program: initial temperature 100°C, increase at 20°C / min to 260°C and hold for 5 min, then increase at 20°C / min to 300°C and hold for 1 min; carrier gas: helium, column flow rate 1.5 mL / min; injection volume: 1 μL; injection mode: splitless injection; injection port temperature: 280°C;

[0020] Mass spectrometry conditions: chromatographic-mass spectrometry interface temperature, 280°C; ionization mode, EI; ion source temperature, 230°C; transfer line temperature, 320°C; scanning mode, selected ion scanning (SIM); quadrupole mass analyzer temperature, 150°C; ionization energy, 70 eV; solvent delay, 4 min; detection mode, selected ion; run time, 16 min.

[0021] Preferably, the characteristic ions for gas chromatography-mass spectrometry analysis in step (3) are: the quantitative ion m / z 185, and the qualitative ions m / z 112 and m / z 197 of diisooctyl sebacate.

[0022] The present invention also protects the application of the aforementioned determination method to the determination of diisooctyl sebacate content in polyvinyl acetate. To effectively investigate the safety and potential risks of polyvinyl acetate, a food contact material, the present invention utilizes GC-MS technology to study diisooctyl sebacate in the material and establishes accurate and efficient qualitative and quantitative detection techniques to rapidly identify and accurately detect the substance.

[0023] The present invention has the following advantages over existing technologies: after dissolving polyvinyl acetate, the present invention employs a "primary precipitation + auxiliary precipitation" approach to purify the sample matrix, followed by gas chromatography-mass spectrometry analysis and detection. Compared with primary precipitation alone, the method proposed in the present invention utilizes auxiliary precipitation, resulting in better purification effects. For diisooctyl sebacate of the same known concentration, the former exhibits higher response and recovery rates. Furthermore, the method effectively protects the instrumentation and chromatographic columns, meeting higher detection requirements, such as reducing the detection limit. Furthermore, the method is simple and rapid to operate, and has broad application prospects. Description of the drawings:

[0024] Figure 1Gas chromatograms of diisooctyl sebacate obtained in Example 5 and Comparative Example 1; 1 in the figure represents the use of a main precipitant + an auxiliary precipitant (i.e., Example 5), and 2 represents the use of only the main precipitant (i.e., Comparative Example 1). Specific implementation method:

[0025] Below in conjunction with the embodiment of the present invention, technical scheme of the present invention is clearly and completely described, it is obvious that described embodiment is only a part of embodiment of the present invention, rather than whole embodiment. Based on the embodiment in the present invention, every other embodiment obtained by those of ordinary skill in the art without making creative work premise all falls within the scope of protection of the present invention. Unless otherwise specified, the equipment and reagent used in the present invention are conventional commercial products in the art.

[0026] Example 1

[0027] A method for determining the content of dioctyl sebacate in polyvinyl acetate comprises the following steps:

[0028] (1) Preparation of standard working solution:

[0029] Preparation of 1000 mg / L dioctyl sebacate stock solution: Accurately weigh 10 mg of dioctyl sebacate standard into a 10 mL volumetric flask and dilute to the mark with methanol to obtain a 1000 mg / L stock solution.

[0030] Preparation of 10 mg / L dioctyl sebacate standard intermediate solution: Pipette 0.1 mL of dioctyl sebacate stock solution into a 10 mL volumetric flask and dilute to the mark with a 1:1 volume ratio of methanol to isopropanol to obtain a 10 mg / L standard intermediate solution.

[0031] Preparation of standard working solution: Accurately pipette the 10 mg / L dioctyl sebacate standard intermediate solution and dilute it step by step to prepare standard working solutions with concentrations of 0.1 mg / L, 0.2 mg / L, 0.5 mg / L, 1.0 mg / L, and 2.0 mg / L.

[0032] (2) Preparation of test solution:

[0033] (a) Sample pretreatment: Weigh approximately 3.00–4.00 g of polyvinyl acetate sample and cut it into 5 mm × 5 mm pieces with scissors. Place the sample into a pre-prepared, clean cryo-crushing cylinder and freeze-crush the sample with liquid nitrogen for 2 min until the sample is reduced to a powdery solid with a particle size of 100–200 μm.

[0034] (b) Sample Extraction: Weigh the ground polyvinyl acetate sample obtained in step (a) into a clean volumetric flask and dissolve it in 10 mL of acetone, shaking the flask until it is completely dissolved. Add 5 mL of methanol dropwise to the flask, shaking the flask while adding, until no further polymer precipitation is observed. Add 3 mL of isopropanol dropwise to the flask until precipitation is complete. Dose the volume to the mark with isopropanol. Shake the solution thoroughly and allow it to stand. Take 5 mL of the supernatant, concentrate it to 1 mL under nitrogen, filter it with an organic filter membrane, and use it for gas chromatography-mass spectrometry analysis.

[0035] (3) Preparation of blank sample: Dissolve the sample in 10 mL of acetone in a 25 mL volumetric flask without sample. Add methanol dropwise to the flask, then add isopropanol dropwise to the flask, and adjust the volume to the calibrated mark with isopropanol. Shake the solution thoroughly and let it stand. Take 5 mL of the supernatant, concentrate it to 1 mL with nitrogen, filter it with an organic filter membrane, and then test it.

[0036] (4) The standard working solution and the test solution were analyzed by gas chromatography-mass spectrometry. The injection port temperature was selected to be 280°C. Under full scan and selected ion conditions, the quantitative ion of diisooctyl sebacate was determined to be 185, and the qualitative ions were 112 and 197.

[0037] The operating parameters of gas chromatography-mass spectrometry are:

[0038] Chromatographic conditions: HP-5MS capillary column, 30 m × 0.25 mm, 0.25 μm; temperature program: initial temperature 100°C, increase at 20°C / min to 260°C and hold for 5 min, then increase at 20°C / min to 300°C and hold for 1 min; carrier gas: helium, column flow rate 1.5 mL / min; injection volume: 1 μL; injection mode: splitless injection; injection port temperature: 280°C;

[0039] Mass spectrometry conditions: chromatographic-mass spectrometry interface temperature, 280°C; ionization mode, EI; ion source temperature, 230°C; transfer line temperature, 320°C; scanning mode, selected ion scanning (SIM); quadrupole mass analyzer temperature, 150°C; ionization energy, 70 eV; solvent delay, 4 min; detection mode, selected ion; run time, 16 min.

[0040] Gas chromatography-tandem mass spectrometry analysis and confirmation of positive results: Analyze the sample and standard working solution using the above-described gas chromatography-mass spectrometry conditions. If the sample's mass chromatographic peak retention time matches that of the standard and both target selected ion pairs are present, confirm the positive result based on the type and relative abundance ratio of the qualitative selected ion pairs. For qualitative analysis, if the allowable deviation of the relative abundance does not exceed the range specified in Table 1, the presence of the corresponding target substance in the sample is confirmed.

[0041] Table 1 Maximum allowable deviation of relative ion abundance ratios for confirmation of positive results

[0042]

[0043] Inject the blank sample and sample solution sequentially. After subtracting the blank background, calculate the chromatographic peak area of ​​dioctyl sebacate. Inject each solution twice in parallel and calculate the average peak area. Ensure consistent operating conditions throughout the measurement of the sample and standard working solution. Quantification is performed using the external standard method.

[0044] Example 2: Selection of dissolving solvent

[0045] Polyvinyl acetate is soluble in organic solvents such as benzene, acetone, and chloroform. A positive sample of dioctyl sebacate was frozen and crushed, then dissolved in benzene, acetone, and chloroform. The experiments revealed that chloroform dissolves vinyl acetate more slowly, while benzene and acetone dissolve equally well. For the same mass of material, benzene requires slightly more solvent. Therefore, based on comprehensive considerations, acetone is preferred as the dissolution solvent, as it is more environmentally friendly and less toxic.

[0046] Example 3: Selection of primary precipitant

[0047] With reference to the precipitant selected for the dissolution and precipitation of phthalates in plastic resins, methanol was preferred as the main precipitant. The precipitation effects of n-hexane and petroleum ether were also compared. The results are shown in Table 2.

[0048] As can be seen from Table 2, methanol has the best precipitation effect and petroleum ether has the worst precipitation effect. Therefore, methanol is selected as the main precipitant.

[0049] Table 2 Precipitation effect of three solvents on polyvinyl acetate

[0050]

[0051] Example 4: Selection of precipitation aids

[0052] Although adopting methanol as precipitation agent, obtain visible supernatant, but still there is the tiny polymer small molecule invisible to the naked eye in the supernatant, form larger sample matrix solution background, weaken the response of target object on chromatogram, long time sample introduction analysis simultaneously, cause polymer small molecule accumulation, also may cause burden to chromatographic system.Therefore the present embodiment, according to the characteristic of material, selects isopropyl alcohol, water and heptane to test as precipitation aid, by the mode of secondary precipitation, carries out deep purification.The polymer small molecule in supernatant is precipitated more thoroughly, further reduce the interference of plastic matrix to target object detection, improve the response of target object on chromatogram simultaneously.

[0053] Experimental method: Weigh 2.0g of each sample known to be free of dioctyl sebacate into a volumetric flask, add 0.025mL, 0.1mL, and 0.2mL of a 1000mg / L standard solution (the solvent used for this mixed standard solution is acetone), use methanol as a precipitant, and prepare multiple dioctyl sebacate sample solutions. Use isopropanol, water, and heptane as co-precipitants for separate tests. Add equal volumes of the three solutions dropwise, preparing two replicates for each solution, and gently shake the volumetric flask during the process. After standing for 10 minutes, take 5mL of the supernatant, concentrate it to 1mL with nitrogen purge, filter it with an organic filter membrane, and use it for gas chromatography-mass spectrometry analysis. The solution was tested after treatment, and the test results of the target substances obtained are shown in Table 3.

[0054] Table 3 Precipitation effect of precipitants

[0055]

[0056] As can be seen from Table 3, when the sample solutions were treated with different precipitants, it can be seen that at the same concentration, the recovery rate of the target compound in the solution treated with water was the lowest, followed by heptane, while the recovery rate of isopropanol was closest to 100%. Therefore, isopropanol was selected as the precipitant.

[0057] Example 5: Linear range, detection limit, and quantification limit

[0058] A method for determining the content of dioctyl sebacate in polyvinyl acetate comprises the following steps:

[0059] (1) Preparation of standard working solution:

[0060] Preparation of 1000 mg / L dioctyl sebacate stock solution: Accurately weigh 10 mg of dioctyl sebacate standard into a 10 mL volumetric flask and dilute to the mark with methanol to obtain a 1000 mg / L stock solution.

[0061] Preparation of 10 mg / L dioctyl sebacate standard intermediate solution: Pipette 0.1 mL of dioctyl sebacate stock solution into a 10 mL volumetric flask and dilute to the mark with a 1:1 volume ratio of methanol to isopropanol to obtain a 10 mg / L standard intermediate solution.

[0062] Preparation of standard working solutions: dioctyl sebacate standard intermediate solution with a concentration of 10 mg / L was diluted stepwise to prepare standard working solutions with concentrations of 0.1 mg / L, 0.2 mg / L, 0.5 mg / L, 1.0 mg / L, and 2.0 mg / L.

[0063] (2) Preparation of test solution:

[0064] (a) Sample pretreatment: Weigh approximately 3.00–4.00 g of polyvinyl acetate sample and cut it into 5 mm × 5 mm pieces with scissors. Place the sample into a clean, pre-prepared cryo-crushing cylinder and freeze-crush the sample with liquid nitrogen for 2 min until the sample is reduced to a powdery solid with a particle size of 100–200 μm.

[0065] (b) Sample Extraction: Weigh the ground polyvinyl acetate sample obtained in step (a) into a clean 25 mL volumetric flask and dissolve it in 10 mL of acetone, shaking the flask until it is completely dissolved. Add 5 mL of methanol dropwise to the flask, shaking the flask while adding, until no further polymer precipitation is observed. Add 3 mL of isopropanol dropwise to the flask until precipitation is complete, and then adjust the volume to the designated mark with isopropanol. Shake the solution thoroughly and let it stand. Take 5 mL of the supernatant, concentrate it to 1 mL under nitrogen, filter it with an organic filter membrane, and use it for gas chromatography-mass spectrometry analysis.

[0066] (3) The standard working solution and the test solution were analyzed by gas chromatography-mass spectrometry. The injection temperature was selected to be 280°C. Under full scan and selected ion conditions, the quantitative ion of diisooctyl sebacate was determined to be 185, and the qualitative ions were 112 and 197.

[0067] The gas chromatography-mass spectrometry operating parameters were as follows: chromatographic conditions: HP-5MS capillary column, 30 m × 0.25 mm, 0.25 μm; heating program: initial temperature 100°C, increase to 260°C at 20°C / min and hold for 5 min, then increase to 300°C at 20°C / min and hold for 1 min; carrier gas: helium, column flow rate 1.5 mL / min; injection volume: 1 μL; injection mode: splitless injection; injection port temperature: 280°C;

[0068] Mass spectrometry conditions: chromatographic-mass spectrometry interface temperature, 280°C; ionization mode, EI; ion source temperature, 230°C; transfer line temperature, 320°C; scanning mode, selected ion scanning (SIM); quadrupole mass analyzer temperature, 150°C; ionization energy, 70 eV; solvent delay, 4 min; detection mode, selected ion; run time, 16 min.

[0069] Under the above assay conditions, standard working solutions (0.1-2.0 mg / L) were tested. A standard working curve was plotted with the concentration of each standard expressed in mg / L as the abscissa and the average peak area as the ordinate, yielding a linear equation and correlation coefficient. The test results demonstrated a good linear relationship between concentration and response. The linear equation and correlation coefficient are shown in Table 4.

[0070] As can be seen from Table 4, within the linear range of 0.2-10 mg / L, the linear correlation coefficient of diethyl sebacate is greater than 0.995, which can well meet the needs of the test work.

[0071] Table 40. Linear relationship between 2 and 10 mg / L

[0072]

[0073] Detection limit and quantification limit: The detection limit and quantification limit of the method proposed in the present invention are determined by the sensitivity of dioctyl sebacate in GC-MS detection. A sample with a blank sample matrix is ​​tested according to the optimized measurement conditions to obtain an extract. The extract with the blank sample matrix is ​​used to prepare a series of standard solutions with a concentration of 0.2-1.0 mg / L for testing. A signal-to-noise ratio (S / N) of 3 times is used as the minimum detection limit, and the detection limit concentration obtained is calculated by the standard deviation S of 7 repeated tests. MDL × coefficient T (n-1，1-α＝0.99) The validity of the detection limit was verified when T was 3.143 with 7 replicates and a 99% confidence level. This was established when the calculated value was ≤ the detection limit derived from the signal-to-noise ratio. Using a 10x signal-to-noise ratio (S / N) as the limit of quantification, the detection limit for dioctyl sebacate was 0.25 mg / kg, and the limit of quantification was 0.5 mg / kg.

[0074] Recovery and Precision of the Method: Recovery of dioctyl sebacate was tested using a blank sample spiked with the target compound. Blank samples containing no target compound were extracted according to the method in step (b) and prepared at three concentration levels: 1.5 mg / L, 10 mg / L, and 40 mg / L. Recovery and precision tests were performed six times at each concentration. The results are detailed in Table 5.

[0075] Table 5 Recovery and precision

[0076]

[0077]

[0078] The test results show that the spiked recovery of diethylhexyl sebacate in polyvinyl acetate determined by this method is between 99.3% and 104.4%, and the relative standard deviation is less than 7.4%, indicating that this method has good recovery and precision.

[0079] Comparative Example 1

[0080] The same as Example 5, except that no precipitation aid is added.

[0081] The results of Example 5 were compared with those of Comparative Example 1, and the response results of the target objects obtained were shown in Table 6.

[0082] Table 6 Precipitation effect of precipitants

[0083]

[0084] As can be seen from Table 6, the test results obtained in Comparative Example 1 without the addition of a precipitant ranged from 76% to 87.6%, while the test results using isopropyl alcohol as a precipitant achieved a recovery rate closest to 100%. This indicates that the "dissolution-primary precipitation-assisted precipitation" method for determining diisooctyl sebacate in polyvinyl acetate significantly reduces interference from the sample matrix compared to the traditional "dissolution-primary precipitation" method, resulting in higher accuracy.

[0085] The description of the above embodiments is only used to help understand the technical solution and core ideas of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for determining the content of dioctyl sebacate in polyvinyl acetate, characterized in that: The steps include: (1) Preparation of test solution: (a) Sample pretreatment: Weigh approximately 3.00–4.00 g of polyvinyl acetate sample and cut it into 5 mm × 5 mm pieces with scissors. Place the sample into a clean, pre-prepared cryo-crushing cylinder and freeze-crush the sample with liquid nitrogen for 2 min until the sample is ground into a powdery solid with a particle size of 100–200 μm. (b) Sample Extraction: Weigh the ground polyvinyl acetate sample obtained in step (a) and place it in a clean 25 mL volumetric flask. Dissolve it in 10 mL of acetone, shaking the flask until it is completely dissolved. Add methanol dropwise to the flask, shaking the flask while adding, until no more polymer precipitation is observed. The amount of methanol added is 5 mL. Add 3 mL of isopropanol dropwise to the flask until precipitation is complete. Make up the volume to the calibration mark with isopropanol. Shake the solution in the flask thoroughly and let it stand. Take 5 mL of the supernatant, concentrate it to 1 mL by nitrogen purge, and filter it through an organic filter membrane to obtain the sample solution for gas chromatography-mass spectrometry analysis. (2) Preparation of standard working solution; (3) Gas chromatography-mass spectrometry: The standard working solution and the test solution were analyzed by gas chromatography-mass spectrometry.

2. The measuring method according to claim 1, wherein The operating parameters of the gas chromatography-mass spectrometry in step (3) are: Chromatographic conditions: HP-5MS capillary column, 30 m × 0.25 mm, 0.25 μm; temperature program: initial temperature 100°C, increase to 260°C at 20°C / min and hold for 5 min, then increase to 300°C at 20°C / min and hold for 1 min; carrier gas: helium, column flow rate 1.5 mL / min; injection volume: 1 mL; injection mode: splitless injection; injection port temperature: 280°C; Mass spectrometry conditions: chromatographic-mass spectrometry interface temperature, 280°C; ionization mode, EI; ion source temperature, 230°C; transfer line temperature, 320°C; scan mode, selected ion scanning (SIM); quadrupole mass analyzer temperature, 150°C; ionization energy, 70 eV; solvent delay, 4 min; detection mode, selected ion; run time, 16 min.

3. The measuring method according to claim 1, wherein Characteristic ions of gas chromatography-mass spectrometry analysis in step (3) are: quantitative ion m / z 185, and qualitative ions m / z 112 and m / z 197 of diisooctyl sebacate.

4. The use of the method according to any one of claims 1 to 3, characterized in that Applied to the determination of diethylhexyl sebacate content in polyvinyl acetate.

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