A method for the determination of methyl acrylate and methyl methacrylate in soil and sediments

Abstract

The present application belongs to the technical field of soil and sediment detection, and relates to a method for determining methyl acrylate and methyl methacrylate in soil and sediment, which comprises sample collection and moisture content determination, sample pretreatment, purging and trapping enrichment, gas chromatography-mass spectrometry detection and internal standard method quantification. By adding an internal standard and a surrogate standard solution to the sample, after purging, dry blowing, thermal desorption and baking treatment, the sample is separated by split injection and programmed temperature chromatography, data is collected in full scan mode, qualitative analysis is performed according to retention time and characteristic ions, and quantitative analysis is performed by internal standard standard curve method. The present method is suitable for soil and sediment matrix, can eliminate matrix interference, has no target compound detection in blank, and meets the requirements of environmental monitoring in terms of detection sensitivity, precision and accuracy. The present method is convenient to operate, has strong stability, can realize accurate quantitative detection of methyl acrylate and methyl methacrylate in soil and sediment, and is suitable for actual environmental monitoring and batch sample analysis.

Description

Technical Field

[0001] This invention belongs to the field of soil and sediment detection technology, specifically relating to a method for determining methyl acrylate and methyl methacrylate in soil and sediment. Background Technology

[0002] Methyl acrylate and methyl methacrylate are widely used organic chemical raw materials, extensively used in plastics, coatings, adhesives, and other fields. These substances are volatile and toxic, and can easily enter the soil and sediment environment through leakage and volatilization during production, transportation, and disposal, posing a potential threat to ecosystems and human health. With the deepening of soil pollution prevention and control efforts in my country, accurate detection of these pollutants in soil and sediments is a crucial technical foundation for conducting pollution investigations, risk assessments, and remediation.

[0003] Currently, the mainstream detection technique for volatile organic compounds (VOCs) in environmental samples is purge-trap-gas chromatography-mass spectrometry (PCMS). This method is highly sensitive, requires no organic solvent extraction, and has been widely used for multi-component screening of matrices such as water and soil. However, existing methods are mostly designed for broad-spectrum VOCs, and there are significant shortcomings in the specific detection of methyl acrylate (MEA) and methyl methacrylate (MMA): First, they are not well-suited to complex matrices such as soil and sediments, and are easily affected by humus and minerals, resulting in large fluctuations in recovery rates and poor accuracy. Second, they lack detection sensitivity and specificity; some methods have high detection limits, making it difficult to detect trace amounts, and the chromatographic separation parameters are not specifically optimized, leading to peak overlap and false positives. Third, the standardization of the methods is low, with inconsistent operating procedures throughout the process, resulting in poor repeatability of results from different laboratories, which is not conducive to widespread application.

[0004] Furthermore, my country's current environmental standards system lacks specific standards for the detection of methyl acrylate and methyl methacrylate in soil and sediments. Existing methods are mostly industry-specific or enterprise-internal, suffering from inconsistencies in parameters and insufficient validation data, thus failing to provide standardized and reliable technical support for soil pollution prevention and control. Therefore, there is an urgent need to develop a detection method that is adaptable to soil and sediment matrices, highly specific, highly sensitive, and with standardized procedures to fill the current technological gap and provide solid technical support for environmental monitoring and pollution control. Summary of the Invention

[0005] To address the problems mentioned in the background art, this invention proposes a method for determining methyl acrylate and methyl methacrylate in soil and sediments. The method optimizes the entire detection process based on the matrix characteristics of soil and sediments, and is adapted to both types of samples from sample collection and preservation, pretreatment to instrument parameter settings. It can effectively eliminate matrix interference, and no target substances are detected in blank samples. It can be specifically applied to the detection of two target substances in soil and sediments, and is suitable for the application needs of actual environmental monitoring.

[0006] The technical solution adopted by this invention to solve its technical problem is: to provide a method for determining methyl acrylate and methyl methacrylate in soil and sediments, comprising the following steps:

[0007] Samples were collected in accordance with soil and sediment sampling specifications, and the moisture content of the collected samples was determined.

[0008] Add internal standard solution and substitute standard solution to the sample vial containing the sample to complete the sample pretreatment;

[0009] The pretreated sample was transferred into a purge trap and subjected to purge, dry purge, thermal desorption and baking treatment in sequence. The analyte after thermal desorption was then introduced into a gas chromatograph-mass spectrometer.

[0010] The analytes were separated using gas chromatography with split injection and programmed temperature, and the data were acquired using mass spectrometry in full scan mode.

[0011] Qualitative analysis was performed using the retention time and characteristic ions of methyl acrylate and methyl methacrylate. An internal standard method was used, and a working curve was established with the ratio of the target analyte to the internal standard content as the x-axis and the ratio of the target analyte quantitative ion response value to the internal standard response value as the y-axis to complete the quantitative detection.

[0012] Furthermore, in S1, the samples are transported under refrigeration after collection, sealed and stored below 4°C, and the test is completed within 7 days; the moisture content is determined by taking a quantitative sample, drying it at a constant temperature to a constant weight, and then converting it into the ratio of the mass difference of the sample before and after drying to the mass of the sample before drying.

[0013] Furthermore, in S2, the standard solution for the substitute is a mixed solution containing dibromofluoromethane, toluene-d8, and 4-bromofluorobenzene, with methanol as the solvent, and the mass concentration of each component is 23-27 mg / L.

[0014] Furthermore, in S2, the internal standard solution is a mixed solution containing fluorobenzene, chlorobenzene-d5, and 1,4-dichlorobenzene-d4, with each component having a mass concentration of 25 mg / L, using methanol as the solvent.

[0015] Furthermore, in S3, the processing conditions of the purge and trap instrument are as follows: purge sample volume 5 mL, purge flow rate 38-42 mL / min, purge temperature 38-42℃, purge time 10-12 min, dry purge time 1.5-2.5 min; pre-desorption temperature of the trap tube 240-250℃, desorption temperature 240-260℃, desorption time 1.5-2.5 min, baking temperature 270-280℃, baking time 10-12 min; the purge gas is high-purity nitrogen, and the carrier gas for backflushing the trap tube is high-purity nitrogen.

[0016] Furthermore, in S4, the gas chromatography detection conditions are as follows: the chromatographic column is a DB-624 quartz capillary column with dimensions of 60m×250μm×1.4μm; the injection port temperature is 210-230℃, the injection is in split mode with a split ratio of 60:1; the column flow rate is 1.0-1.2mL / min; the temperature program is as follows: initial temperature 35-40℃ held for 1.5-2min, temperature increased to 110-120℃ at 8-12℃ / min, and then temperature increased to 230-250℃ at 13-17℃ / min and held for 5-7min.

[0017] Furthermore, in S4, the mass spectrometry detection conditions are as follows: ion source temperature is 225-235℃, transfer line temperature is 240-260℃, quadrupole temperature is 150-160℃; ion source electron energy is 70-80eV, mass scan range is 35~270amu; and data acquisition mode is full scan.

[0018] Further, in S5, the internal standard used in the internal standard method is fluorobenzene, with a mass concentration of 50.0 μg / L. Methyl acrylate and methyl methacrylate standard solutions, along with the substitute standard solution, are added to blank reagent water to prepare a series of standard solutions with concentrations of 10.0, 20.0, 50.0, 100, and 200 μg / L. A portion of the standard solution is placed in a sample vial, and the internal standard solution is added to bring the internal standard mass concentration to 50.0 μg / L. The concentrations are measured sequentially from low to high according to instrument conditions, and the retention times and quantitative ion response values ​​of the target analyte and the internal standard are recorded. A working curve is established with the ratio of the target analyte to the internal standard content as the abscissa and the ratio of the target analyte to the internal standard response value as the ordinate.

[0019] Furthermore, the methyl acrylate and methyl methacrylate standard solutions are prepared by stepwise dilution of a mixed standard solution of methyl acrylate and methyl methacrylate in methanol to obtain standard solutions with a mass concentration of 25 mg / L. Compared with the prior art, the beneficial effects of the present invention are:

[0020] (1) The method of the present invention optimizes the entire detection process for the matrix characteristics of soil and sediment. From sample collection and preservation, pretreatment to instrument parameter settings, it is suitable for both types of samples. It can effectively eliminate matrix interference, and no target substances are detected in blank samples. It can be specifically applied to the detection of two target substances in soil and sediment, and is suitable for the application needs of actual environmental monitoring.

[0021] (2) The method of the present invention clarifies the full process specifications and standardized parameters of sample collection, preservation, moisture content determination and purge and trap, and gas chromatography-mass spectrometry detection. The instruments used are conventional detection equipment and the reagents are high-purity general reagents. No special customized consumables are required. The operation process is clear and the parameters are fixed, which facilitates standardized detection in the laboratory. It has strong feasibility for implementation and promotion. Detailed Implementation

[0022] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1:

[0024] 1. Instruments and equipment

[0025] Table 1 Experimental Instruments and Equipment and Models

[0026]

[0027] 2. Validation of standard substances and reagents

[0028] Methyl acrylate: Product code: 25020524, 99.9%, Manufacturer: Tanmo, Expiry date: 2029.03.02;

[0029] Methyl methacrylate: Product code: 25060297, concentration 99.9%, manufacturer: Tanmo, expiration date: 2031.06.12;

[0030] Three substitutes for methanol: Product code: 2426921, concentration: 2000 μg / mL, manufacturer: Anpu, expiration date: 2029.02.18;

[0031] Three internal standards for methanol: No. 2422903, concentration 2000 μg / mL, manufacturer: Anpu, expiration date: 2029.08.04;

[0032] Standard solutions of three substitutes in methanol: dibromofluoromethane, toluene-d8, and 4-bromofluorobenzene, all with a mass concentration of 2000 mg / L, product number: 2426921, concentration 2000 μg / mL, manufacturer: Anpu, expiration date: 2029.02.18;

[0033] The mixed standard working solution of dibromofluoromethane, toluene-d8, and 4-bromofluorobenzene in methanol: The mass concentrations of dibromofluoromethane, toluene-d8, and 4-bromofluorobenzene are all 25 mg / L. Accurately transfer 125 μL of the mixed standard solution of fluorobenzene, chlorobenzene-d5, and 1,4-dichlorobenzene-d4 in methanol into a 10 mL volumetric flask, dilute to the mark with methanol, and mix well.

[0034] Substitutes: These are substances not present in the sample but with similar physicochemical properties to the target analyte. They are generally added before sample extraction or other pretreatment. Recovery rates can be used to evaluate the impact of the sample matrix and sample processing on the analytical results.

[0035] Three internal standard solutions in methanol: fluorobenzene, chlorobenzene-d5, and 1,4-dichlorobenzene-d4, all with a mass concentration of 2000 mg / L, product number: 2422903, concentration 2000 μg / mL, manufacturer: Anpu, expiration date: 2029.08.04;

[0036] The mixed standard solution of fluorobenzene, chlorobenzene-d5, and 1,4-dichlorobenzene-d4 in methanol is prepared by using a pipette. The mass concentrations of fluorobenzene, chlorobenzene-d5, and 1,4-dichlorobenzene-d4 are all 25 mg / L. 125 μL of the mixed standard solution of fluorobenzene, chlorobenzene-d5, and 1,4-dichlorobenzene-d4 in methanol is accurately transferred to a 10 mL volumetric flask and diluted to the mark with methanol. The mixture is then thoroughly mixed.

[0037] Methyl acrylate and methyl methacrylate standard solutions in methanol: The mass concentration of methyl acrylate and methyl methacrylate is 20000 mg / L. Accurately weigh 0.2000 g of methyl acrylate and 0.2000 g of methyl methacrylate into a 10 mL volumetric flask containing methanol, dissolve in methanol and dilute to the mark, and mix well.

[0038] Methyl acrylate and methyl methacrylate standard working solutions in methanol: The mass concentration of methyl acrylate and methyl methacrylate is 25.0 mg / L. Accurately transfer 12.5 μL of the methyl acrylate and methyl methacrylate standard solutions in methanol into a 10 mL volumetric flask, dilute to the mark with methanol, and mix well.

[0039] 3. Confirmation of environmental conditions

[0040] The laboratory is equipped with ventilation facilities and vibration-damping test benches. The analytical instrument room is equipped with an air conditioning system to monitor and record temperature and humidity. The temperature is controlled within the range of 5℃ to 35℃, and the relative humidity is controlled below 85%. The laboratory environmental conditions can meet the requirements of the testing method standards and the environmental control requirements of the instruments and equipment.

[0041] 4. Method Validation

[0042] Method Principles

[0043] Volatile organic compounds in the sample were concentrated in a collection tube after purging with high-purity nitrogen. The collection tube was then heated and backflushed with high-purity helium. The thermally desorbed components were introduced into a gas chromatograph, separated, and then detected by a mass spectrometer. Qualitative analysis was performed by comparing the mass spectra with those of the target analyte standard and by using retention times, while quantification was performed using the internal standard method.

[0044] Sample collection and preservation

[0045] Soil and sediment samples should be collected in accordance with the relevant provisions of HJ / T 166 and GB17378.3, respectively. Portable instruments for volatile organic compound (VOC) determination can be used on-site to initially screen samples for target analyte content. At least three parallel samples should be collected for each sample, and an additional sample should be collected in a 60 mL sample bottle (or a larger size sample bottle) to determine the VOC content and moisture content of the high-content sample.

[0046] Before sampling, place a clean magnetic stir bar in each 40 mL brown sample bottle, seal it, label it, and weigh it (accurate to 0.01 g). Record the weight and indicate it on the label. During sampling, use a sampler to collect an appropriate amount of sample into the sample bottle, quickly remove any sample adhering to the threads and outer surface of the sample bottle, and seal the sample bottle.

[0047] Samples should be transported under refrigeration after collection. They should be analyzed as soon as possible after being returned to the laboratory. The laboratory storage area should be free from inorganic substances, and samples should be stored below 4°C for up to 7 days.

[0048] Determination of sample moisture content

[0049] Take 5 g (accurate to 0.01) of sample and dry it at (105±5)℃ for at least 6 h. Calculate the moisture content by dividing the difference in sample mass before and after drying by the sample mass before drying and then multiplying by 100. (%), accurate to 0.1%.

[0050] 5. Instrument conditions

[0051] 5.1 Reference Conditions for Purge and Trap Instruments

[0052] Purge and trap apparatus: Purge sample volume: 5 mL; Purge flow rate: 40 mL / min; Purge temperature: 40℃; Purge time: 11 min; Dry purge time: 2 min; Pre-desorption temperature: 245℃; Desorption temperature: 250℃; Desorption time: 2 min; Baking temperature: 280℃; Baking time: 10 min.

[0053] 5.2 Reference Conditions for Gas Chromatography-Mass Spectrometer

[0054] 5.2.1 Gas Chromatography-Mass Spectrometry (GC-MS): Instrument: Agilent 7890B-5977A; Column: DB-624 (60m × 250μm × 1.4μm); Injector temperature: 220℃; Split mode; Split ratio: 60:1; Temperature program: Initial temperature 38℃, hold for 1.8 min, increase to 120℃ at 10℃ / min, then increase to 240℃ at 15℃ / min, hold for 6 min; Column flow rate: 1.0 mL / min.

[0055] 5.2.2 Mass spectrometer: Ion source temperature: 230℃; transfer line temperature: 250℃; quadrupole temperature: 150℃; ion source electron energy: 70 eV; mass range: 35~270 amu; data acquisition mode: full scan.

[0056] 6. Standard Curve

[0057] 6.12 Standard Series Formulation of VOCs (Methyl Acrylate and Methyl Methacrylate)

[0058] Standard solution preparation process:

[0059] Using a microsyringe, transfer a certain amount of the standard working solution and the surrogate standard solution to blank reagent water to prepare a standard series of the target analyte and the surrogate (two VOC concentration standards: 10.0, 20.0, 50.0, 100, and 200 μg / L). Using an airtight syringe, measure 5.00 mL of the above standard solutions into 40 mL sample vials, and add a certain amount of internal standard solution to each vial to ensure that the internal standard concentration at each point is 50.0 µg / L. According to the instrument reference conditions, determine the concentrations sequentially from low to high, and record the retention time of the target analyte and the corresponding internal standard, as well as the response value of the quantitative ion (first or second characteristic ion). Establish a working curve with the ratio of the target analyte to the internal standard concentration on the x-axis and the ratio of the corresponding response value to the internal standard response value on the y-axis.

[0060] Table 2. Standard working curves and linear relationships of two volatile organic compounds (VOCs)

[0061]

[0062] 7. Method precision and accuracy

[0063] 7.1 Accuracy and precision of standard samples

[0064] Table 3. Description of spiking test conditions for quartz sand sample matrix

[0065]

[0066] Table 4. Precision and accuracy results of spiking methyl acrylate and methyl methacrylate in quartz sand matrix.

[0067]

[0068] 7.2 Soil sample matrix recovery rate and precision

[0069] Table 5. Description of soil sample matrix spiking test conditions (spiking concentration: 10.0 µg / L)

[0070]

[0071] Table 6. Precision and accuracy results of spiking methyl acrylate and methyl methacrylate in soil samples.

[0072] (Spike concentration: 10.0 µg / L)

[0073]

[0074] Table 7. Description of soil sample matrix spiking test conditions (spiking concentration: 40.0 µg / L)

[0075]

[0076] Table 8. Precision and accuracy results of spiking methyl acrylate and methyl methacrylate in soil samples.

[0077] (Spiked concentration: 40.0 µg / L)

[0078]

[0079] 7.3 Matrix recovery and precision of sediment samples

[0080] Table 9. Description of spiking conditions for sediment sample matrix (spiking concentration: 100 µg / L)

[0081]

[0082] Table 10. Precision and accuracy results of spiking methyl acrylate and methyl methacrylate in sediment samples.

[0083] (Spike concentration: 100 µg / L)

[0084]

[0085] Table 11. Description of spiking conditions for sediment sample matrix (spiking concentration: 100 µg / L)

[0086]

[0087] Table 12 Precision and accuracy results of spiking methyl acrylate and methyl methacrylate in sediment samples

[0088] (Spike concentration: 100 µg / L)

[0089]

[0090] 8. Limit of detection and limit of quantification

[0091] Method detection limit = S (standard deviation of n blank parallel experiments) × t （n-1,0.99） (t-distribution with n-1 degrees of freedom and 99% confidence level (one-sided))

[0092] Method limit of determination: The method limit of determination is calculated by using a concentration that is 4 times the detection limit based on the method limit of detection.

[0093] Add 5.0 g of quartz sand to each of the 10 purge bottles, then add 4.0 µl of standard working solution (10.0 mg / L) and 5.0 µl of substitute standard solution (50 mg / L) to each bottle, and finally add 10.0 µl of internal standard working solution (25 mg / L). Immediately cap and seal the bottles, shake well, and analyze them sequentially according to the instrument reference conditions. The measurement data are shown in Tables 13 and 14.

[0094] Table 13 Validation results of the method detection limits for methyl acrylate and methyl methacrylate

[0095]

[0096] Table 14. Compliance Verification Results of Detection Limits and Lower Measure Limits for Methyl Acrylate and Methyl Methacrylate

[0097]

[0098] In summary, this embodiment validated the method for determining methyl acrylate and methyl methacrylate in soil and sediment using purge-trap-gas chromatography-mass spectrometry (GC-MS). The entire process was standardized and the operation was regulated. All instruments and reagents used were conventional and general-purpose, with no special customization requirements. The method detection limit was as low as 2.3–2.4 μg / kg, and the lower limit of quantification met the requirements of HJ168-2020. The RSD of the detection precision under various matrices was less than 6%, and the recovery rate was within a reasonable range. It effectively eliminated matrix interference from soil and sediment, and no target analytes were detected in the blank sample. This method is highly specific, sensitive, and reproducible, demonstrating excellent feasibility for implementation and promotion. It can accurately achieve qualitative and quantitative detection of two target analytes in soil and sediment, providing reliable technical support for soil pollution investigation, risk assessment, and remediation, and filling the industry gap in dedicated detection methods for these pollutants.

[0099] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for determining methyl acrylate and methyl methacrylate in soil and sediments, characterized in that, Includes the following steps: S1. Collect samples according to the soil and sediment sampling specifications, and determine the moisture content of the collected samples; S2. Add internal standard solution and substitute standard solution to the sample vial containing the sample to complete the sample pretreatment; S3. Transfer the pretreated sample into the purge trap and perform purge, dry purge, thermal desorption and baking treatment in sequence. The analyte after thermal desorption is then introduced into the gas chromatograph-mass spectrometer. S4. The analyte is separated by gas chromatography with split injection and programmed temperature, and the data is acquired by mass spectrometry in full scan mode. S5. Qualitative analysis was performed using the retention time and characteristic ions of methyl acrylate and methyl methacrylate. An internal standard method was used, with the ratio of the target analyte to the internal standard content as the abscissa and the ratio of the target analyte quantitative ion response value to the internal standard response value as the ordinate, to establish a working curve for quantitative detection.

2. The method for determining methyl acrylate and methyl methacrylate in soil and sediments according to claim 1, characterized in that, In S1, samples are transported under refrigeration after collection, sealed and stored below 4°C, and tested within 7 days. The moisture content is determined by taking a quantitative sample, drying it at a constant temperature to a constant weight, and then converting the difference in mass between the sample before and after drying to the mass of the sample before drying.

3. The method for determining methyl acrylate and methyl methacrylate in soil and sediments according to claim 1, characterized in that, In S2, the standard solution for the substitute is a mixed solution containing dibromofluoromethane, toluene-d8, and 4-bromofluorobenzene in methanol as solvent, with each component having a mass concentration of 23-27 mg / L.

4. The method for determining methyl acrylate and methyl methacrylate in soil and sediments according to claim 1, characterized in that, In S2, the internal standard solution is a mixed solution containing fluorobenzene, chlorobenzene-d5, and 1,4-dichlorobenzene-d4, with each component having a mass concentration of 25 mg / L, using methanol as the solvent.

5. The method for determining methyl acrylate and methyl methacrylate in soil and sediments according to claim 1, characterized in that: In S3, the processing conditions of the purge and trap instrument are as follows: purge sample volume 5 mL, purge flow rate 38-42 mL / min, purge temperature 38-42℃, purge time 10-12 min, dry purge time 1.5-2.5 min; pre-desorption temperature of the trap tube 240-250℃, desorption temperature 240-260℃, desorption time 1.5-2.5 min, baking temperature 270-280℃, baking time 10-12 min; the purge gas is high-purity nitrogen, and the carrier gas for backflushing the trap tube is high-purity nitrogen.

6. The method for determining methyl acrylate and methyl methacrylate in soil and sediments according to claim 1, characterized in that: In S4, the gas chromatography detection conditions are as follows: the chromatographic column is a DB-624 quartz capillary column with dimensions of 60m×250μm×1.4μm; the injection port temperature is 210-230℃, the injection mode is split, the split ratio is 60:1; the column flow rate is 1.0-1.2mL / min; the temperature program is as follows: initial temperature 35-40℃, hold for 1.5-2min, increase the temperature to 110-120℃ at 8-12℃ / min, and then increase the temperature to 230-250℃ at 13-17℃ / min and hold for 5-7min.

7. The method for determining methyl acrylate and methyl methacrylate in soil and sediments according to claim 1, characterized in that: In S4, the mass spectrometry detection conditions are as follows: ion source temperature is 225-235℃, transfer line temperature is 240-260℃, quadrupole temperature is 150-160℃; ion source electron energy is 70-80eV, mass scan range is 35~270amu; data acquisition mode is full scan.

8. The method for determining methyl acrylate and methyl methacrylate in soil and sediments according to claim 1, characterized in that: In S5, the internal standard used in the internal standard method is fluorobenzene, with a mass concentration of 50.0 μg / L. Methyl acrylate and methyl methacrylate standard solutions, along with the substitute standard solution, are added to blank reagent water to prepare a series of standard solutions with concentrations of 10.0, 20.0, 50.0, 100, and 200 μg / L. A portion of the standard solution is placed in a sample vial, and the internal standard solution is added to bring the internal standard mass concentration to 50.0 μg / L. The concentrations are measured sequentially from low to high according to instrument conditions, and the retention times and quantitative ion response values ​​of the target analyte and the internal standard are recorded. A working curve is established with the ratio of the target analyte to the internal standard content as the abscissa and the ratio of the target analyte to the internal standard response value as the ordinate.

9. The method for determining methyl acrylate and methyl methacrylate in soil and sediments according to claim 8, characterized in that, The methyl acrylate and methyl methacrylate standard solutions are prepared by gradually diluting a mixed standard solution of methyl acrylate and methyl methacrylate in methanol with methanol to obtain standard solutions with a mass concentration of 25 mg / L.

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