A method for preparing a matrix standard substance of 21-component phenolic endocrine disruptors in soil

Abstract

The application discloses a preparation method of a 21-component phenolic endocrine disruptor matrix standard substance in soil, which comprises the following steps: using high-standard farmland soil as an original matrix, performing acetone gradient extraction cleaning, ethanol gradient extraction cleaning and drying treatment on the original matrix soil to obtain clean matrix soil, and adding 21 kinds of phenolic compounds with accurate purity in a stepwise increasing manner to prepare the 21-component phenolic endocrine disruptor matrix standard substance in soil, wherein the corresponding concentration content can be accurately controlled in the range of 5 mg / kg to 10 mg / kg. The application provides a preparation process and a split process of the standard substance, the prepared standard substance is stable in composition, can be stored for 36 months under the conditions of light shielding and refrigeration, and the method is stable, reliable, and highly reproducible, and has a good popularization and application prospect.

Description

Technical Field

[0001] This invention relates to the field of standard material technology, and in particular to a method for preparing a standard material matrix of 21 phenolic endocrine disruptors in soil. Background Technology

[0002] In the fields of environmental monitoring and agricultural product safety, phenolic endocrine disruptors (EDCs) in soil have become a key target for soil environmental quality monitoring and food safety risk assessment due to their bioaccumulation, environmental persistence, and potential carcinogenic, teratogenic, and mutagenic risks. Developing soil matrix standard materials that are consistent with the actual soil sample matrix and have accurate and reliable values ​​is of great significance for achieving quality control throughout the detection process and ensuring the accuracy and comparability of monitoring data.

[0003] The existing technologies for preparing reference materials of phenolic endocrine disruptors in soil have the following main drawbacks: First, naturally occurring phenolic compounds or historical pollution residues in the soil background are difficult to completely remove, seriously affecting the accuracy of the measurements; second, traditional mechanical mixing methods are difficult to achieve uniform mixing of trace phenolic compounds with large quantities of soil; at the same time, phenolic compounds are chemically reactive and have poor long-term stability under conventional preparation and storage conditions; finally, there is a lack of domestically developed soil matrix reference materials for trace phenolic compounds, and we still rely on imported products, which are expensive and have limited supply channels. Therefore, this invention proposes a method for preparing a matrix standard of 21 phenolic endocrine disruptors in soil. The method removes background phenolic residues from the soil through acetone gradient extraction and ethanol gradient extraction. A step-by-step mixing technique combined with low-temperature argon-protected gas flow pulverization is used to achieve uniform mixing of trace amounts of multi-component phenolic compounds with large quantities of soil. Furthermore, the use of PTFE containers, P2O5 drying, and inert gas protection effectively solves the technical challenges of soil background interference, poor uniformity, and insufficient stability. This invention fills the gap in domestic soil matrix standard materials for trace multi-component phenolic compounds, providing accurate and reliable technical support for soil environmental monitoring, agricultural product quality and safety testing, and laboratory quality control, and has significant scientific value and socio-economic benefits. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a matrix standard of 21 phenolic endocrine disruptors in soil.

[0005] To achieve the above objectives, the present invention is implemented according to the following technical solution: This invention includes the following steps: Farmland soil samples were collected, and soil samples in which no phenolic compounds were detected were selected as the original matrix soil samples. The original matrix soil samples were stored in a sealed PETF container. The total mass of the original matrix soil samples was approximately 50 kg. The inner wall of the PETF container was made of polytetrafluoroethylene. The original substrate soil sample was washed by acetone gradient extraction, then by ethanol gradient extraction, and finally dried to obtain clean substrate soil. In a nitrogen atmosphere operating chamber, weigh 1g of each of the 21 phenolic compounds into the same dry, clean, sealed bottle and mix them evenly. Store the mixture at room temperature, away from light and in a dry environment. The phenolic compounds in the sealed bottle are transferred to the mixing tank through the inlet of an argon gas jet mill; the mixing tank is a PTFE tank with a capacity of 50 kg. A total of 50 kg of clean substrate soil was mixed with 21 kinds of phenolic compounds in a graded and incremental manner to obtain substrate standard materials, which were then aliquoted and stored.

[0006] Furthermore, the method for performing acetone gradient extraction and washing includes: Add 80L of chromatographic grade acetone to a sealed PETF container, seal the container, place it on a three-dimensional mixer and mix for a preset time, then drain the excess acetone solution. The acetone gradient extraction and washing process was performed four times. The preset times for the acetone gradient extraction and washing are 48 hours, 24 hours, 12 hours, and 12 hours, respectively.

[0007] Furthermore, the method for performing ethanol gradient extraction and washing includes: Add 80L of clean chromatographic grade ethanol to a sealed PETF container, seal the container, place it on a three-dimensional mixer and mix for a preset time, then remove the excess ethanol solution. The ethanol gradient extraction and washing process is repeated three times. The preset times for the ethanol gradient extraction and washing are 48 hours, 24 hours, and 12 hours, respectively.

[0008] Furthermore, the drying process includes: Soil samples in sealed PETF containers were air-dried naturally, placed in an oven at 180°C for 48 hours, cooled to room temperature, and then stored in sealed PETF containers for later use.

[0009] Furthermore, the 21 phenolic endocrine disruptors include: phenol, 2-chlorophenol, 2-methylphenol, 4-methylphenol, 3-methylphenol, 2,4-dimethylphenol, 2-nitrophenol, 2,4-dichlorophenol, 2,6-dichlorophenol, 4-chloro-3-methylphenol, 2,4,6-trichlorophenol, 2,4,5-trichlorophenol, 2,4-dinitrophenol, 4-nitrophenol, 2,3,4,6-tetrachlorophenol, 2,3,4,5-tetrachlorophenol, 2,3,5,6-tetrachlorophenol, 4,6-dinitro-o-cresol, pentachlorophenol, dichlorophenol, and dichlorophenol.

[0010] Furthermore, the method for performing graded incremental mixing includes: Weigh a pre-set mass of clean substrate soil and transfer it to a mixing drum through the feed inlet of an argon gas flow pulverizer. The solids in the mixing drum are then pulverized and mixed at a mesh size of 60 for a pre-set time. The pulverization and mixing are carried out at a temperature of -10°C and in an argon atmosphere. The number of times the graded incremental mixing is performed is 4; The preset mass for graded incremental mixing is 5kg, 10kg, 15kg, and 20kg, and the corresponding preset time is 24 hours, 48 ​​hours, 48 ​​hours, and 60 hours.

[0011] Furthermore, the method for repackaging and storing includes: In an argon atmosphere operating chamber, brown high-density polyethylene bottles are filled with argon gas beforehand. Then, the matrix standard material is dispensed into brown high-density polyethylene bottles. Finally, argon gas is filled above the bottles containing soil samples. The polyethylene bottles are then sealed, evacuated, and frozen for storage.

[0012] The beneficial effects of this invention are: This invention provides a method for preparing a matrix standard of 21 phenolic endocrine disruptors from soil. Compared with existing technologies, this invention has the following technical advantages: This invention utilizes a synergistic process of acetone gradient extraction and ethanol gradient extraction, combined with a high-temperature drying process, to thoroughly remove residual phenolic compounds and organic interfering substances from the soil background. The resulting pure soil matrix ensures the accuracy and specificity of the values ​​of 21 target phenolic compounds, avoiding systematic errors caused by background interference. This invention employs a small-scale, incremental mixing strategy. First, a mixture of 21 phenolic compounds is initially mixed with a small amount of soil. Then, the amount of soil added is gradually increased and the mixing time is extended accordingly. The mixture is pulverized and mixed under a low-temperature argon atmosphere. This effectively solves the technical problem of uniformly mixing trace compounds with large quantities of soil, ensuring that the standard substances have good uniformity between and within the bottles. The method provided by this invention can prepare 21-component phenolic endocrine disruptor matrix standard substances in soil with a concentration of 5.00 mg / kg to 10.0 mg / kg. The standard substances are stable and can be stored for 36 months under light-proof and frozen conditions, combined with the dispensing process. The preparation method is stable, reliable, and highly reproducible, and has good prospects for promotion and application. Attached Figure Description

[0013] Figure 1 This is a flowchart illustrating the steps of a method for preparing a matrix standard of 21 phenolic endocrine disruptors in soil according to the present invention. Detailed Implementation

[0014] The present invention will be further described below through specific embodiments. The illustrative embodiments and descriptions herein are used to explain the present invention, but are not intended to limit the present invention.

[0015] The present invention discloses a method for preparing a matrix standard of 21 phenolic endocrine disruptors in soil, comprising the following steps: like Figure 1 As shown, this embodiment includes the following steps: Farmland soil samples were collected, and soil samples in which no phenolic compounds were detected were selected as the original matrix soil samples. The original matrix soil samples were stored in a sealed PETF container. The total mass of the original matrix soil samples was approximately 50 kg. The inner wall of the PETF container was made of polytetrafluoroethylene. The original substrate soil sample was washed by acetone gradient extraction, then by ethanol gradient extraction, and finally dried to obtain clean substrate soil. In a nitrogen atmosphere operating chamber, weigh 1g of each of the 21 phenolic compounds into the same dry, clean, sealed bottle and mix them evenly. Store the mixture at room temperature, away from light and in a dry environment. The phenolic compounds in the sealed bottle are transferred to the mixing tank through the inlet of an argon gas jet mill; the mixing tank is a PTFE tank with a capacity of 50 kg. A total of 50 kg of clean substrate soil was mixed with 21 kinds of phenolic compounds in a graded and incremental manner to obtain substrate standard materials, which were then aliquoted and stored.

[0016] In practice, high-standard farmland soil samples were collected in accordance with the relevant provisions of HJ / T 166. The high-standard farmland soil samples were analyzed and tested using HJ 703-2014 "Determination of Phenolic Compounds in Soil and Sediments by Gas Chromatography". High-standard farmland soil samples were screened (soil samples in which no phenolic compounds were detected were selected as the original matrix soil samples). The original matrix soil samples with a total mass of about 50 kg were stored in a sealed PETF container with a polytetrafluoroethylene inner wall. Acetone gradient extraction and washing of the original substrate soil sample: 80L of chromatographic grade acetone was added to a sealed PETF container, the container was sealed and placed on a three-dimensional mixer for 48 hours, and the excess acetone solution was exported. 80L of chromatographic grade acetone was added to the sealed PETF container a second time, the container was sealed and placed on a three-dimensional mixer for 24 hours, and the excess acetone solution was exported. 80L of chromatographic grade acetone was added to the sealed PETF container a third time, the container was sealed and placed on a three-dimensional mixer for 12 hours, and the excess acetone solution was exported. 80L of chromatographic grade acetone was added to the sealed PETF container a fourth time, the container was sealed and placed on a three-dimensional mixer for 12 hours, and the excess acetone solution was exported. The original soil sample that had undergone acetone gradient extraction and cleaning was then subjected to ethanol gradient extraction and cleaning: 80L of clean chromatographic grade ethanol was added to a sealed PETF container, the container was sealed and placed on a three-dimensional mixer for 48 hours, and the excess ethanol solution was drained. 80L of clean chromatographic grade ethanol was added to the sealed PETF container, the container was sealed and placed on a three-dimensional mixer for 24 hours, and the excess ethanol solution was drained. 80L of clean chromatographic grade ethanol was added to the sealed PETF container, the container was sealed and placed on a three-dimensional mixer for 12 hours, and the excess ethanol solution was drained. After the original soil sample has been cleaned by gradient ethanol extraction, it is removed from the sealed PETF container and air-dried. It is then placed in an oven at 180°C for 48 hours, cooled to room temperature, and returned to the sealed PETF container for later use. In a nitrogen atmosphere operating chamber, weigh 1g of each of the 21 phenolic compounds into the same dry, clean, sealed bottle and mix them evenly. Store the mixture at room temperature, away from light and in a dry environment. The phenolic compounds in the sealed bottle are transferred to the mixing tank through the inlet of an argon gas jet mill; the mixing tank is a PTFE tank with a capacity of 50 kg. The 21 phenolic compounds include: phenol (CAS: 108-95-2, purity ≥99.9%), 2-chlorophenol (CAS: 95-57-8, purity ≥99.9%), 2-methylphenol (CAS: 95-48-7, purity ≥99.5%), 4-methylphenol (CAS: 106-44-5, purity ≥99.5%), 3-methylphenol (CAS: 108-39-4, purity ≥99.5%), and 2,4-dimethylphenol. (CAS: 105-67-9, purity ≥99.9%), 2-nitrophenol (CAS: 88-75-5, purity ≥99.5%), 2,4-dichlorophenol (CAS: 120-83-2, purity ≥99.5%), 2,6-dichlorophenol (CAS: 87-65-0, purity ≥99.9%), 4-chloro-3-methylphenol (CAS: 59-50-7, purity ≥99.5%), 2,4,6-trichlorophenol (CAS: 88- 06-2, purity ≥99.6%), 2,4,5-trichlorophenol (CAS: 95-95-4, purity ≥99.9%), 2,4-dinitrophenol (CAS: 51-28-5, purity ≥99.9%), 4-nitrophenol (CAS: 100-02-7, purity ≥99.8%), 2,3,4,6-tetrachlorophenol (CAS: 58-90-2, purity ≥99.9%), 2,3,4,5-tetrachlorophenol (CAS: 4901) -51-3, purity ≥99.9%), 2,3,5,6-tetrachlorophenol (CAS: 935-95-5, purity ≥99.9%), 4,6-dinitro-o-cresol (CAS: 534-52-1, purity ≥99.5%), pentachlorophenol (CAS: 87-86-5, purity ≥99.5%), dichlorophenol (CAS: 88-85-7, purity ≥99.8%), and acaricide (CAS: 131-89-5, purity ≥99.7%).

[0017] A total of 50 kg of clean substrate soil was mixed with 21 phenolic compounds in a graded, incremental manner to obtain substrate standard materials: 5 kg of clean substrate soil was weighed and transferred to a mixing tank through the inlet of an argon gas jet mill. The solids in the mixing tank were then pulverized and mixed at a 60-mesh screen for 24 hours. A second batch of 10 kg of clean substrate soil was weighed and transferred to the mixing tank through the inlet of an argon gas jet mill. The solids in the mixing tank were then pulverized and mixed at a 60-mesh screen for 48 hours. A third batch of 15 kg of clean substrate soil was weighed... The soil sample was transferred to a mixing tank through the inlet of an argon gas jet mill. The solids in the mixing tank were then pulverized and mixed using a 60-mesh pulverizer for 48 hours. A fourth batch of 20 kg of clean soil was weighed and transferred to the mixing tank through the inlet of the argon gas jet mill. The solids in the mixing tank were then pulverized and mixed using a 60-mesh pulverizer for another 60 hours to obtain a uniformly granulated and well-mixed standard reference material of 21 phenolic compounds in the soil matrix. The temperature environment and gas atmosphere during the pulverization and mixing process were -10℃. In an argon atmosphere operating chamber, brown high-density polyethylene bottles are filled with argon gas beforehand. Then, the matrix standard material is dispensed into brown high-density polyethylene bottles. Finally, argon gas is filled above the bottles containing soil samples. The polyethylene bottles are then sealed, evacuated, and frozen for storage.

[0018] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. 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 preparing a matrix standard of 21 phenolic endocrine disruptors in soil, characterized in that, Includes the following steps: S1. Collect farmland soil samples, screen soil samples that do not contain phenolic compounds as original matrix soil samples, and store the original matrix soil samples in a sealed PETF container; the total mass of the original matrix soil samples is approximately 50 kg; the inner wall of the PETF container is made of polytetrafluoroethylene. S2. The original substrate soil sample was washed by acetone gradient extraction, then by ethanol gradient extraction, and finally dried to obtain clean substrate soil. S3. In a nitrogen atmosphere operating chamber, weigh 1g of each of the 21 phenolic compounds into the same dry and clean sealed bottle and mix them evenly. Store at room temperature, protected from light and in a dry environment. S4. Take the phenolic compound from the sealed bottle and transfer it to the mixing tank through the inlet of the argon gas flow pulverizer; the mixing tank is a PTFE tank with a capacity of 50kg. S5. Take 50 kg of clean substrate soil and mix it with 21 kinds of phenolic compounds in a graded and incremental manner to obtain substrate standard materials. Then, the substrate standard materials are aliquoted and stored.

2. The method for preparing a matrix standard material of 21 phenolic endocrine disruptors in soil according to claim 1, characterized in that, The method for performing acetone gradient extraction and washing includes: Add 80L of chromatographic grade acetone to a sealed PETF container, seal the container, place it on a three-dimensional mixer and mix for a preset time, then drain the excess acetone solution. The acetone gradient extraction and washing process was performed four times. The preset times for the acetone gradient extraction and washing are 48 hours, 24 hours, 12 hours, and 12 hours, respectively.

3. The method for preparing a matrix standard material of 21 phenolic endocrine disruptors in soil according to claim 1, characterized in that, The method for performing ethanol gradient extraction and washing includes: Add 80L of clean chromatographic grade ethanol to a sealed PETF container, seal the container, place it on a three-dimensional mixer and mix for a preset time, then remove the excess ethanol solution. The ethanol gradient extraction and washing process is repeated three times. The preset times for the ethanol gradient extraction and washing are 48 hours, 24 hours, and 12 hours, respectively.

4. The method for preparing a matrix standard material of 21 phenolic endocrine disruptors in soil according to claim 1, characterized in that, The drying process includes: Soil samples in sealed PETF containers were air-dried naturally, placed in an oven at 180°C for 48 hours, cooled to room temperature, and then stored in sealed PETF containers for later use.

5. The method for preparing a matrix standard material of 21 phenolic endocrine disruptors in soil according to claim 1, characterized in that, The 21 phenolic compounds include: phenol, 2-chlorophenol, 2-methylphenol, 4-methylphenol, 3-methylphenol, 2,4-dimethylphenol, 2-nitrophenol, 2,4-dichlorophenol, 2,6-dichlorophenol, 4-chloro-3-methylphenol, 2,4,6-trichlorophenol, 2,4,5-trichlorophenol, 2,4-dinitrophenol, 4-nitrophenol, 2,3,4,6-tetrachlorophenol, 2,3,4,5-tetrachlorophenol, 2,3,5,6-tetrachlorophenol, 4,6-dinitro-o-cresol, pentachlorophenol, dichlorophenol, and acaricide.

6. The method for preparing a matrix standard material of 21 phenolic endocrine disruptors in soil according to claim 1, characterized in that, The method for graded incremental mixing includes: Weigh a pre-set mass of clean substrate soil and transfer it to a mixing drum through the feed inlet of an argon gas flow pulverizer. The solids in the mixing drum are then pulverized and mixed at a mesh size of 60 for a pre-set time. The pulverization and mixing are carried out at a temperature of -10°C and in an argon atmosphere. The stepwise incremental mixing is performed 4 times; The preset mass for graded incremental mixing is 5kg, 10kg, 15kg, and 20kg, and the corresponding preset time is 24 hours, 48 ​​hours, 48 ​​hours, and 60 hours.

7. The method for preparing a matrix standard material of 21 phenolic endocrine disruptors in soil according to claim 1, characterized in that, The method for dispensing and storing includes: In an argon atmosphere operating chamber, brown high-density polyethylene bottles are filled with argon gas beforehand. Then, the matrix standard material is dispensed into brown high-density polyethylene bottles. Finally, argon gas is filled above the bottles containing soil samples. The polyethylene bottles are then sealed, evacuated, and frozen for storage.

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