Determination and evaluation method for plasticizer in aging product of plastic product

Abstract

The invention discloses a method for determining and evaluating a plasticizer in an aging product of a plastic product, which belongs to the technical field of detection and analysis, and comprises the following steps: (1) crushing the plastic product, and then adding artificial fresh water; (2) carrying out suction filtration and reserving leachate for later use; (3) activating and balancing the solid-phase extraction column by using methanol and deionized water, and eluting the leachate treated in the step (2) for later use; (4) concentrating the eluent under mild nitrogen until the eluent is nearly dry, fixing the volume by using methanol, and passing through a 0.22 mu m organic filter membrane to obtain an extract for later use; (5) carrying out detection by utilizing HPLC-MS / MS; (6) determining an LC50 measured value of the phthalic acid ester component according to the measured phthalic acid ester component; and (7) carrying out toxicity calculation on different types of phthalate components. The method disclosed by the invention can give consideration to concentration and toxicity double factors, and is more scientific and risk oriented; based on model prediction, preliminary screening can be completed without a large number of biological experiments, and time and resources are saved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of detection analysis, and particularly relates to a method for determining and evaluating plasticizers in aging products of plastic products. BACKGROUND

[0002] Plasticizers, also known as plasticizers, are a kind of polymer material additives widely added in plastic products. There are many types of plasticizers, and the most common type is phthalate plasticizer. Phthalate plasticizers generally refer to ester compounds formed by phthalic acid and 4-15 carbon alkyl alcohol, which are a kind of commonly used plastic additives in industry. The structure mainly has benzene ring, long-chain or branched alkane and carbonate group. Because its structure is similar to hormones, it is also called "environmental hormone". Long-term contact or ingestion will seriously affect the endocrine system and hormone level of human body, and even affect the development of sexual organs of adolescents. Its toxicity is much higher than that of melamine. It must stay in the body for a period of time before being discharged. Long-term use may cause decline of immunity and reproductive ability. Therefore, phthalate esters have been listed as the fourth type of toxic chemical substances in some areas. Therefore, the detection of phthalate plasticizers and their content in plastics is of great importance to the quality control of plastic products and the study of pollutants.

[0003] Phthalate esters (PAEs) are widely used as plasticizers for plastic products, and have the characteristics of easy migration and easy release. Studies have shown that microplastics can continuously release PAEs during environmental aging, which can cause potential toxicity to aquatic organisms, especially fish and benthic animals. There are two main problems in the current research on pollutants released by microplastics: first, the traditional screening of phthalate esters (PAEs) pollutants only focuses on concentration and ignores toxicity intensity; second, the types of substances released by microplastics are various, and there is a lack of scientific and efficient toxicity priority screening method. SUMMARY

[0004] The purpose of the present application is to provide a method for determining and evaluating plasticizers in aging products of plastic products, which is a combined evaluation method based on leaching concentration and toxicity equivalent factor (TEF), and can systematically evaluate the toxicity contribution of different PAEs, and realize the identification and screening of high-priority pollutants in microplastics.

[0005] The method for determining and evaluating plasticizers in aging products of plastic products provided by the present application comprises the following steps: (1) The disposable plastic products are crushed and then artificial fresh water is added; (2) Then, the mixture is shaken in a constant temperature shaker for 5-7 days, and the filtrate is obtained after the solid-liquid mixture is filtered and reserved; (3) The solid phase extraction column is activated and balanced by methanol and deionized water, and after the mixed internal standard is added to the percolate treated in step (2), the HLB solid phase extraction column is used for enrichment treatment, the column is vacuum dried for 2h, then 10 mL of methanol is used to elute the column, and the eluate is collected in a glass tube for standby; (4) The eluate is concentrated to near dryness under gentle nitrogen, and then diluted with methanol, and then filtered through a 0.22 μm organic filter membrane to obtain the extract for standby; (5) Detection by HPLC-MS / MS; (6) For the determined phthalate ester components, the LC 50 measured value; (7) Toxicity calculation is performed for different types of phthalate ester components, and the calculation is performed according to the following formula: TU i = C i / LC 50i ; Wherein, C i is the measured concentration of the i-th phthalate ester component; LC 50i is the LC 50 of the corresponding monomer; TU is the toxicity value; i takes the value of 1, 2, 3, …; (8) Toxicity contribution ratio calculation is performed for different types of phthalate ester components, and the calculation is performed according to the following formula: First, calculate the total toxicity: ΣTU=∑ i TU i ; Then calculate the toxicity contribution rate: Contributioni=TU / ΣTU×100%.

[0006] Further, the crushing treatment in step (1) is then placed in an artificial aging oven for aging treatment for 35-40 days.

[0007] Further, the components and contents contained in the artificial fresh water in step (1) are: 63 mg / L NaHCO3, 5.5 mg / L KCl, 123.3 mg / L MgSO4 and 294 mg / L CaCl2, and the balance is water.

[0008] Further, the shaking treatment in step (2) is performed at a shaking speed of 200-300 rpm, 25°.

[0009] Further, the mixed internal standard in step (3) is composed of DMP-d4, DEP-d4, DBP-d4, DiBP-d4, DOP-d4 and DEHP-d4, each with a concentration of 100 μg / mL.

[0010] Further, the detection conditions of the HPLC-MS / MS in step (5) are as follows: BETASIL C18 chromatographic column, 5 μm, 100 mm x 2.1 mm, column temperature 40 DEG C, injection volume 1 μL; mobile phase: A is 0.1% methanolic ammonium solution, B is methanol solution, flow rate 0.2 mL / min, gradient elution.

[0011] Further, the gradient elution program is as follows: 0 ~ 1.5 min, 10.0% B; 1.6 ~ 3.0 min, 10 ~ 95% B; 3.1 ~ 7.0 min, 95% B; 7.1 ~ 7.5 min, 95 ~ 10% B; 7.6 ~ 10 min, 10% B.

[0012] Further, the LC 50 The measured value is specifically retrieved from the LC 50 measured value; if the database shows that "50% lethal is not reached at the highest measurable concentration", it is recorded as LC 50 ≥ the highest test concentration, which is taken as a conservative estimate in the calculation; the unit is μg / L, and the source of each data, exposure stage and solvent condition are recorded; when there are multiple LC 50 values for the same monomer, the data with a time length of 96 h and high methodological quality are preferred, and if necessary, the median or geometric mean is used as the representative value.

[0013] Advantages of the present application: The method of the present application can take into account both concentration and toxicity, and is more scientific and risk-oriented; it can be based on model prediction, and can complete the preliminary screening without a large number of biological experiments, saving time and resources; it can also be extended to other microplastic materials and pollutant species, and has strong universality; it can provide clear preferred basis in actual operation, support efficient toxicological verification experiment design, and provide effective reference for safety evaluation and pollutant limit value formulation of disposable plastic products. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The actual leaching concentration of the plasticizer measured for Example 2 of the present application; Figure 2The plasticizer toxicity contribution rate measured for Example 2 of the present application. DETAILED DESCRIPTION

[0015] The specific embodiments of the present application are described in further detail in conjunction with the accompanying drawings, examples, and comparative examples. The following examples are used to illustrate the present application, but are not used to limit the scope of the present application.

[0016] Example 1: A determination and evaluation method for plasticizers in aging products of plastic products, comprising the following steps: (1) The disposable plastic products are crushed and then added with artificial fresh water; (2) Then, the mixture is shaken in a constant temperature shaker for 5-7 days, and the filtrate is obtained after the solid-liquid mixture is filtered and reserved; (3) The solid phase extraction column is activated and balanced with methanol and deionized water, the mixed internal standard is added to the filtrate treated in step (2), and the HLB solid phase extraction column is used for enrichment treatment, the column is vacuum dried for 2h, then 10 mL of methanol is used to elute the column, and the eluate is collected in a glass tube for standby; (4) The eluate is concentrated to near dryness under mild nitrogen, and then the methanol is used to make up the volume, and the extract is obtained through a 0.22 μm organic filter membrane for standby; (5) Detection is performed by using HPLC-MS / MS; (6) For the determined phthalate ester components, the LC 50 measured value; (7) The toxicity of different types of phthalate ester components is calculated, which is calculated according to the following formula: TU i = C i / LC 50i ; Wherein, C i is the measured concentration of the i-th phthalate ester component; LC 50i is the LC 50 of the corresponding monomer; TU is the toxicity value; i is 1, 2, 3, …; (8) The toxicity contribution ratio of different types of phthalate ester components is calculated, which is calculated according to the following formula: First, the total toxicity is calculated: ΣTU=∑ i TU i ; Then, the toxicity contribution rate is calculated: Contributioni=TU / ΣTU×100%.

[0017] In step (1), the crushed products are placed in an artificial aging oven for aging treatment for 35-40 days.

[0018] The artificial freshwater in step (1) contains the following components and amounts: 63 mg / L NaHCO3, 5.5 mg / L KCl, 123.3 mg / L MgSO4, and 294 mg / L CaCl2, with the balance being water.

[0019] The shaking treatment in step (2) is performed at a shaking speed of 200-300 rpm and 25°.

[0020] The mixed internal standard in step (3) is composed of DMP-d4, DEP-d4, DBP-d4, DiBP-d4, DOP-d4, and DEHP-d4, each at a concentration of 100 μg / mL.

[0021] The detection conditions for HPLC-MS / MS in step (5) are as follows: BETASIL C18 column, 5 μm, 100 mm x 2.1 mm, column temperature 40°C, injection volume 1 μL; mobile phase: A is 0.1% methanolic ammonium solution, B is methanol solution, flow rate 0.2 mL / min, gradient elution, gradient elution program: 0 ~ 1.5 min, 10.0% B; 1.6 ~ 3.0 min, 10 ~ 95% B; 3.1 ~ 7.0 min, 95% B; 7.1 ~ 7.5 min, 95 ~ 10% B; 7.6 ~ 10 min, 10% B.

[0022] The LC in step (6) is performed using an Agilent 1290 Infinity LC system. 50 The measured value is specifically the LC50 value of the corresponding phthalate component of the same species matched with Danio rerio, with a methodological standard and an exposure time of 96 h, retrieved from the ECOTOX database of the United States Environmental Protection Agency. 50 The measured value; if the database shows that the LC50 value has not reached 50% at the highest measurable concentration, it is recorded as LC 50 ≥ the highest test concentration, which is taken as a conservative estimate in the calculation; the unit is μg / L, and the source of each data, the exposure stage, and the solvent conditions are recorded; when there are multiple LC 50 values for the same monomer, the data with a time length of 96 h and high methodological quality are preferred, and if necessary, the median or geometric mean is used as the representative value.

[0023] Example 2: A method for determining and evaluating plasticizers in aging products of plastic products, comprising the following steps: (1) Manually cut and crush disposable polypropylene (PP) plastic cups, crush them with a crusher, put them into an artificial aging chamber for aging treatment for 40 days, then weigh 0.1 g of plastic fragments into a glass bottle with a smooth mouth, add 10 mL of artificial fresh water (63 mg / L NaHCO3, 5.5 mg / L KCl, 123.3 mg / L MgSO4 and 294 mg / L CaCl2, the remainder is water); (2) Then, shake the mixture in a constant temperature shaker at a speed of 200-300 rpm and 25° for 6 days. After filtering the solid-liquid mixture, keep the filtrate for later use. (3) The solid-phase extraction column was activated and equilibrated with methanol and deionized water. 50 ng of mixed internal standard (composed of DMP-d4, DEP-d4, DBP-d4, DiBP-d4, DOP-d4 and DEHP-d4, each with a concentration of 100 μg / mL) was added to the permeate after step (2). The column was then enriched using an HLB solid-phase extraction column (Oasis HLB 6cc 500 mg, Waters). After vacuum drying the column for 2 h, the column was eluted with 10 mL of methanol. The eluent was collected in a glass tube for later use. (4) The eluent was concentrated to near dryness under mild nitrogen, diluted to volume with 1 mL of methanol, and then filtered through a 0.22 μm organic filter membrane to obtain the extract for later use. (5) Detection was performed using HPLC-MS / MS. The detection conditions were: BETASIL C18 column, 5 μm, 100 mm × 2.1 mm, column temperature 40℃, injection volume 1 μL; mobile phase: A was 0.1% ammonium methyl ether aqueous solution, B was methanol solution, flow rate 0.2 mL / min, gradient elution, gradient elution program was: 0 ~ 1.5 min, 10.0% B; 1.6 ~ 3.0 min, 10 ~ 95% B; 3.1 ~ 7.0 min, 95% B; 7.1 ~ 7.5 min, 95 ~ 10% B; 7.6 ~ 10 min, 10% B.

[0024] (6) The measured concentrations (Ci) of the seven PAEs (dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), diisobutyl phthalate (DiBP), benzyl butyl phthalate (BBP), dioctyl phthalate (DOP), and di(2-ethylhexyl) phthalate (DEHP)) were used as the evaluation objects, and the units were uniformly expressed in μg / L. Figure 1 The figure shows the measured concentrations of several PAEs; their LC50 values ​​were determined. 50Measured values; specifically, LC values ​​for the above seven PAEs that are matched with Danio rerio in terms of methodology and exposure duration of 96 h were retrieved from the U.S. Environmental Protection Agency's ECOTOX database. 50 Measured value; if the database shows "lethal at concentrations below 50% of the highest detectable concentration", then record it as LC. 50 ≥The highest test concentration, and use this highest concentration as a conservative estimate in the calculation; record the source, exposure stage, and solvent conditions for each data point; when the same monomer exists in multiple LC... 50 When selecting data, priority should be given to those with a duration consistent with 96 hours and high methodological quality. If merging is necessary, the median or geometric mean should be used as the representative value. For those "DOP" with historical abbreviation ambiguity, it should be clearly defined as "DnOP (di-n-octylphthalate)" and distinguished by its CAS number to avoid confusion with DEHP.

[0025] (7) Toxicity calculations were performed for different types of phthalate esters, specifically according to the following formula: TU i =C i / LC 50i ; Among them, C i LC represents the measured concentration of the i-th phthalate ester; 50i For the corresponding individual zebrafish LC 50 TU represents the toxicity value; i takes values ​​of 1, 2, 3...7. (8) The toxicity contribution percentage of different types of phthalate esters is calculated according to the following formula: First, calculate the overall total toxicity: ΣTU=∑ i TU i ; Recalculate the contribution of toxicity: Contributioni=TU / ΣTU×100%.

[0026] like Figure 2 As shown, the toxicity contribution rates of several PAEs were measured.

[0027] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for determining and evaluating plasticizers in aging products of plastic articles, characterized in that, Includes the following steps: (1) The plastic products are crushed and then artificial fresh water is added; (2) Then, shake the mixture in a constant temperature shaker for 5-7 days, filter the solid-liquid mixture and keep the filtrate for later use; (3) The solid phase extraction column was activated and equilibrated with methanol and deionized water. After adding mixed internal standards to the permeate after step (2), HLB solid phase extraction column was used for enrichment. After vacuum drying the column for 2 hours, the column was eluted with 10 mL of methanol and the eluent was collected in a glass tube for later use. (4) The eluent was concentrated to near dryness under mild nitrogen, and then diluted to volume with methanol before being filtered through a 0.22 μm organic filter membrane to obtain the extract for later use. (5) Detection was performed using HPLC-MS / MS; (6) Determine the LC50 of the phthalate esters that were detected. 50 Measured value; (7) Toxicity calculations were performed for different types of phthalate esters, specifically according to the following formula: TU i =C i / LC 50i ; Among them, C i LC represents the measured concentration of the i-th phthalate ester; 50i For the corresponding individual zebrafish LC 50 TU represents the toxicity value; i takes values ​​of 1, 2, 3, ... (8) The toxicity contribution ratio of different types of phthalate esters is calculated according to the following formula: First, calculate the overall total toxicity: ΣTU=∑ i YOU i ; Recalculate the toxicity contribution rate: Contributioni=TU / ΣTU×100%.

2. The method for determining and evaluating plasticizers in aging products of plastic products according to claim 1, characterized in that, After the crushing process described in step (1), it is placed in an artificial aging chamber for aging treatment for 35-40 days.

3. The method for determining and evaluating plasticizers in aging products of plastic products according to claim 1, characterized in that, The artificial freshwater mentioned in step (1) contains the following components and contents: 63 mg / L NaHCO3, 5.5 mg / L KCl, 123.3 mg / L MgSO4 and 294 mg / L CaCl2, with the remainder being water.

4. The method for determining and evaluating plasticizers in aging products of plastic products according to claim 1, characterized in that, The oscillation process described in step (2) involves oscillating at a speed of 200-300 rpm and 25°.

5. The method for determining and evaluating plasticizers in aging products of plastic products according to claim 1, characterized in that, The mixed internal standard mentioned in step (3) consists of DMP-d4, DEP-d4, DBP-d4, DiBP-d4, DOP-d4 and DEHP-d4, each with a concentration of 100 μg / mL.

6. The method for determining and evaluating plasticizers in aging products of plastic products according to claim 1, characterized in that, The HPLC-MS / MS detection conditions described in step (5) are as follows: BETASIL C18 column, 5 μm, 100 mm × 2.1 mm, column temperature 40℃, injection volume 1 μL; mobile phase: A is 0.1% ammonium methyl methacrylate aqueous solution, B is methanol solution, flow rate 0.2 mL / min, gradient elution.

7. The method for determining and evaluating plasticizers in aging products of plastic products according to claim 6, characterized in that, The gradient elution program is: 0 ~ 1.5 min, 10.0% B; 1.6 ~ 3.0 min, 10 ~ 95% B; 3.1 ~ 7.0 min, 95% B; 7.1 ~ 7.5 min, 95 ~ 10% B; 7.6 ~ 10 min, 10% B.

8. The method for determining and evaluating plasticizers in aging products of plastic products according to claim 1, characterized in that, The LC described in step (6) 50 The measured values ​​were specifically obtained from the LC-100 of the corresponding phthalate components retrieved from the US EPA's ECOTOX database, which matched Danio rerio in terms of methodology and exposure duration of 96 hours. 50 Measured value; if the database displays "lethal at the highest detectable concentration not reaching 50%", then record it as LC. 50 The highest concentration (≥) is used as a conservative estimate in the calculation. The unit is uniformly set in μg / L. Record the source, exposure stage, and solvent conditions for each data point; when the same monomer exists in multiple LC... 50 When selecting data, priority should be given to those with a duration of 96 hours and high methodological quality. If merging is required, the median or geometric mean should be used as the representative value.

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