Method for rapidly extracting and detecting declone in soil and sediment

Abstract

The invention discloses a method for rapidly extracting and detecting declone in soil and sediment, and belongs to the technical field of environment detection. Aiming at declones in soil and sediments, after rapid extraction, chromatographic column purification and concentration, a gas chromatograph-triple quadrupole mass spectrometer is used for analysis and detection. According to the present invention, the declone in the soil and the sediment is detected through the rapid extraction-gas chromatography triple quadrupole mass spectrometer, the detection efficiency of the declone is substantially improved, and the method has advantages of rapid detection, simple operation, good reproducibility, accurate result, high sensitivity and the like, and meets the detection requirements of the declone in the soil and the sediment.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental detection, and more specifically, relates to a method for rapidly extracting and detecting declone in soil and sediment. Background Art

[0002] Declone, or bis(hexachlorocyclopentadiene)cyclooctane, is a highly chlorinated flame retardant with stable chemical properties. It is widely used in industrial polymers such as plastics, fibers, nylon, resins, wire and cable coatings, and computer connectors. Declone has similar characteristics to persistent organic matter, such as high bioaccumulation and long-range migration, and has been found to be ubiquitous in the atmosphere, water, soil, and organisms. Studies have shown that Declone-like substances have neurobehavioral toxicity, can cause damage to the lungs, liver, and reproductive system, and can affect embryonic development. In 2023, my country will include cis- and trans-declone in the list of new pollutants under key control, and will prohibit their production, processing, use, import and export from January 1, 2024. Declone enters the environment through industrial wastewater, waste gas, and electronic waste dismantling. Its strong hydrophobicity, semi-volatility, and lipophilicity make it easily adsorbed in soil and sediments. Therefore, it is urgent to establish an efficient, rapid and accurate method for detecting declone in soil and sediment to provide technical support for subsequent research on the migration and transformation of this compound in environmental media, pollution control, and ecological safety.

[0003] In soil and sediment, decloaking generally exists in trace concentrations (ng / kg-μg / kg). At present, gas chromatography-electron capture detector, gas chromatography / negative chemical ionization source-single quadrupole mass spectrometer, gas chromatography-high resolution mass spectrometer, etc. are commonly used instrumental methods to detect decloaking in environmental media. Among them, gas chromatography-electron capture detector and gas chromatography / negative chemical ionization source-single quadrupole mass spectrometer have high sensitivity to decloaking, but may produce false positive results when detecting complex matrix samples; gas chromatography-high resolution mass spectrometer can improve the accuracy and sensitivity of qualitative analysis, but the instrument is expensive and difficult to popularize. Gas chromatography-triple quadrupole tandem mass spectrometry is a selective and highly sensitive detection method that can avoid false positive results. The method is relatively economical and accurate.

[0004] In addition, the matrix media of soil and sediment are complex, and there will be matrix effects during the detection process, which will interfere with the instrumental detection of declone. In order to improve the sensitivity and accuracy of the entire analytical method, it is necessary to combine sample pretreatment technology with instrumental detection methods. Sample pretreatment technology is one of the key steps in the entire analytical method and will directly affect the accuracy and reliability of the analytical results. At present, Soxhlet extraction and accelerated solvent extraction are mostly used for the extraction of declone in soil and sediment samples.

[0005] The method of determining declone in soil and sediment using gas chromatography-electron capture detector disclosed in the Chinese patent application with publication number CN116068113A uses Soxhlet extraction as a pretreatment method. The extraction time is long (10 h), the entire operation process is complicated, and a large amount of organic reagents are consumed. It is impossible to process large batches of samples at the same time. Xie Hui et al. used two methods, oscillation extraction and accelerated solvent extraction, to extract declone residues in soil and rice. Among them, the accelerated solvent extraction method has a high degree of automation, and the recovery rate of declone is significantly better than that of the oscillation extraction method, but the throughput of the accelerated extractor is small (≤6 digits), which limits its large-scale application. The current extraction methods for declone in soil and sediments are cumbersome, time-consuming, and inefficient. They cannot process multiple batches of samples at the same time and have high operating requirements for experimental personnel. Summary of the invention

[0006] In view of the above problems existing in the prior art, the technical problem to be solved by the present invention is to provide a method for quickly extracting and detecting Declona in soil and sediment, so as to achieve rapid, accurate and efficient determination of the content of Declona in soil and sediment.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for rapidly extracting and detecting declone in soil and sediment comprises the following steps:

[0009] (1) Rapid extraction: Add soil or sediment into a centrifuge tube, then add the substitute solution, adsorbent and organic mixed solvent respectively for extraction and shaking, and then pass through anhydrous sodium sulfate to obtain the extract;

[0010] (2) Purifying the extract: Purify the extract through a glass chromatography column, collect and concentrate the eluent, and add an internal standard solution to obtain the sample solution to be tested;

[0011] (3) Preparation of standard curve: prepare at least five concentrations of cis-Declone and trans-Declone standard working solutions;

[0012] (4) Determination and result analysis: The cis-Declone and trans-Declone standard working solutions of each concentration gradient in step (3) are measured by gas chromatography-triple quadrupole mass spectrometry, and the ratio of the target concentration to the internal standard compound concentration is used as the horizontal coordinate, and the ratio of the response value of the target quantitative ion pair to the response value of the internal standard compound quantitative ion pair is used as the vertical coordinate. Regression analysis is performed to obtain the cis-Declone and trans-Declone standard working curves; under the same conditions, the sample solution to be tested obtained in step (2) is measured by gas chromatography-triple quadrupole mass spectrometry to measure the response values ​​of the characteristic ions of cis-Declone and trans-Declone in the sample solution, and substitute them into the corresponding standard working curves to obtain the cis-Declone and trans-Declone contents in the sample solution, and then the Declone content in the soil or sediment sample is calculated based on the mass of the sample represented by the sample solution.

[0013] Preferably, in step (1), the substitute solution is 13 C-Declon-602, the adsorbent is selected from any one of diatomaceous earth, N-propylethylenediamine solid phase adsorbent, and Mg / Al layered double metal hydroxide, and the organic mixed solvent is selected from any one of an acetone / n-hexane mixed solution with a volume ratio of 1:1, a dichloromethane / n-hexane mixed solution with a volume ratio of 1:1, and an acetone / dichloromethane mixed solution with a volume ratio of 1:1.

[0014] Preferably, in step (1), the substitute solution is 13 C-Declone-602, the adsorbent is Mg / Al layered double hydroxide, and the organic mixed solvent is a dichloromethane / n-hexane mixed solution with a volume ratio of 1:1.

[0015] Preferably, in step (1), the extraction and oscillation time is 10 min to 30 min. More preferably, in step (1), the extraction and oscillation time is 20 min.

[0016] Preferably, in step (2), the specific process of purification by glass chromatography column is as follows: the extract is passed through the glass chromatography column, eluted with 20 mL of organic solvent at a elution rate of 2 mL / min, the eluent is collected, concentrated to 1 mL by nitrogen blowing, and an internal standard is added. 13 C-PCB-209 solution was then used to obtain the test solution.

[0017] Preferably, in step (2), the organic solvent is selected from any one of n-hexane, dichloromethane and acetone. More preferably, the organic solvent is n-hexane;

[0018] Preferably, in step (4), the operating conditions of the gas chromatograph of the gas chromatograph-triple quadrupole mass spectrometer are as follows: injection port temperature: 280°C; splitless injection, high pressure injection, pressure 150 kPa; injection volume: 1.0 μL; chromatographic column: DB-5MS, specification 15 m×0.25 mm×0.1 μm; column box temperature: 100°C for 1 min, increased to 310°C at 20°C / min, and maintained for 2 min; carrier gas mode is constant flow 1.5 mL / min.

[0019] Preferably, in step (4), the operating conditions of the triple quadrupole mass spectrometer of the gas chromatography-triple quadrupole mass spectrometer are: electron bombardment source; ion source temperature of 280°C; ionization energy of 70 eV; transfer line temperature of 300°C; multiple reaction monitoring; and solvent delay of 3.5 min.

[0020] Preferably, in step (2), the preparation process of the glass chromatography column is as follows: a small ball of quartz wool is placed at the bottom of the glass chromatography column, and 1 g of anhydrous sodium sulfate, 4 g of silica gel, 2 g of Florisil and 1 g of anhydrous sodium sulfate are sequentially filled to obtain a glass chromatography column.

[0021] Preferably, before the soil or sediment in step (1) is subjected to oscillation extraction, foreign matter such as branches, leaves, and stones are removed, and the soil or sediment is freeze-dried, ground, and sieved.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention detects Declona in soil and sediment by rapid extraction-gas chromatography triple quadrupole mass spectrometry. This method has the advantages of low detection limit, good reproducibility, accurate results, high sensitivity, etc., and meets the needs of Declona detection in soil and sediment;

[0024] (2) Compared with the prior art, the present invention has simple operation steps, short extraction time, high recovery rate, and can process a large number of samples at the same time, greatly improving the detection efficiency of Declona in soil and sediment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The standard curve diagram of cis-Declone and trans-Declone in Example 1;

[0026] Figure 2 This is the MRM scan of the Deklon standard solution in Example 1 using a gas chromatography-triple quadrupole mass spectrometer. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described below in conjunction with specific embodiments. In the following examples, unless otherwise specified, the technical means used are conventional means well known to those skilled in the art. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0028] The preparation method of the glass chromatography column used in the following examples is as follows: a small ball of quartz wool is placed at the bottom of the glass chromatography column, and 1 g of anhydrous sodium sulfate, 4 g of silica gel, 2 g of florisil and 1 g of anhydrous sodium sulfate are sequentially filled. The preparation method of Mg / Al layered double metal hydroxide is as follows: 2 g of magnesium nitrate and 1.2 g of aluminum nitrate are dissolved in 40 mL of deionized water, and ammonia water is added dropwise during stirring until the pH of the mixed solution is 10. After continuing to stir for a period of time, the mixed solution is centrifuged, washed with deionized water and acetone several times, placed in an oven to dry at 80°C, and ground to obtain the product. The ceramic homogenizer used was purchased from Agilent; the 13 C-Declone-602 solution, 13 C-PCB-209, cis-Declone and trans-Declone were purchased from CIL, Cambridge, USA.

[0029] Example 1

[0030] In this embodiment, soil from a plot of land in Suzhou is used as the test sample.

[0031] This embodiment provides a method for quickly extracting and detecting Declone in soil, which specifically includes the following steps:

[0032] (1) Preparation of soil samples:

[0033] Foreign matter such as branches, leaves, and stones were removed from the soil, and the samples were freeze-dried, ground, and sieved (0.25 mm). The dry matter content of the soil samples was determined according to HJ 613;

[0034] (2) Rapid extraction of soil samples:

[0035] Weigh 10.0 g (accurate to 0.01 g) of sample into a 50 mL centrifuge tube and add 10 μL of substitute 13 C-Declone-602 solution, 100 mg Mg / Al layered double hydroxide, 20 mL of a 1:1 volume ratio dichloromethane / n-hexane mixed solution and a ceramic homogenizer were added in sequence, and the mixture was shaken vigorously for 20 min. After dehydration with anhydrous sodium sulfate, an extract was obtained;

[0036] (3) Purification of the extract:

[0037] The extract was passed through a glass chromatography column and eluted with 20 mL of n-hexane at a rate of 2 mL / min. The eluate was collected and concentrated to 1 mL by nitrogen blowing. 10 μL of internal standard was added. 13 C-PCB-209 solution to obtain the test solution;

[0038] (4) Standard curve configuration:

[0039] Prepare at least 5 standard series with 1 μg / mL cis-Declone and trans-Declone standard solution, with concentrations of 1.0, 2.0, 5.0, 10.0, 20.0, and 50.0 ng / mL. Add 1 μg / mL internal standard 13 C-PCB-209 standard solution was used to make its concentration 10 ng / mL. The ratio of the target compound concentration to the internal standard compound concentration was used as the horizontal axis, and the ratio of the response value of the target compound quantitative ion pair to the response value of the internal standard compound quantitative ion pair was used as the vertical axis to draw a linear regression equation. The results are shown in Figure 1 As shown, the linear regression equation of cis-Declone is y= 81244x + 5973, with a correlation coefficient of 0.9996, and the linear regression equation of trans-Declone is y= 82247x +11, with a correlation coefficient of 0.9994;

[0040] (5) Sample testing:

[0041] The above standard curve and the liquid to be tested were detected by gas chromatography-triple quadrupole mass spectrometry; the operating conditions of the gas chromatograph were as follows: injection port temperature: 280 °C; splitless injection, high pressure injection, pressure 150 kPa; injection volume: 1.0 μL; chromatographic column: DB-5MS (15 m×0.25 mm×0.1 μm); column box temperature: 100 °C for 1 min, increased to 310 °C at 20 °C / min, and maintained for 2 min; carrier gas mode was constant flow 1.5 mL / min; chromatographic column was DB-5MS (15 m×0.25 mm×0.1 μm, Agilent). The operating conditions of the mass spectrometer were as follows: electron bombardment source; ion source temperature was 280 °C; ionization energy was 70 eV; transfer line temperature was 300 °C; multiple reaction monitoring; solvent delay was 3.5 min. The qualitative and quantitative ion parameter settings of Deklon are shown in Table 1. The MRM scanning of Deklon standard solution by gas chromatography-triple quadrupole mass spectrometry is as follows: Figure 2 As shown. Figure 2 It can be seen that the method of the present invention can effectively separate cis-Declone and trans-Declone by gas chromatography-triple quadrupole mass spectrometry.

[0042] Table 1 MRM monitoring conditions of Declone

[0043]

[0044] (6) Spike recovery experiment of actual samples:

[0045] The soil was spiked at three concentration levels: low, medium, and high. The spiked amounts were 0.2 μg / kg, 1 μg / kg, and 4 μg / kg, respectively, and the measurements were performed six times. The sample measurement results, spiked recovery, and relative standard deviation are shown in Table 2.

[0046] Table 2 Experimental results of actual soil samples

[0047]

[0048] As shown in Table 2, the cis-Declone was not detected in the soil sample collected from a soil block in Suzhou, the concentration of trans-Declone was 0.08 μg / kg, and the spiked recoveries of cis-Declone and trans-Declone at low, medium and high concentration levels were 81.7%-101% and 72.3%-102%, respectively, and the relative standard deviations were 1.48%-2.50% and 2.02%-3.97%, respectively. The results show that the method of the present invention has a high recovery rate and good precision for the determination of Declone in soil, and can meet the requirements for the determination of Declone content in soil.

[0049] (7) Sample detection limit

[0050] Quartz sand was used for blank test and 7 low-concentration blank spike experiments. Extraction, purification and instrumental analysis were performed according to steps (1) to (5). The standard deviation (SD) of the 7 low-concentration blank spike results was calculated, and then the sample detection limit (DL = 3.143 × SD) was calculated, as shown in Table 3.

[0051] Table 3 Blank samples and blank spiked samples

[0052]

[0053] As shown in Table 3, using the detection method of the present invention, when the sampling amount is 10.0 g, the detection limits of cis and trans forms of Declona are both 0.01 μg / kg, and the lower limit of determination is 0.04 μg / kg, indicating that the method of the present invention has high sensitivity and is beneficial to the determination of trace Declona in soil and sediment.

[0054] Example 2

[0055] In this embodiment, sediment from a certain place in Suzhou is used as the test sample.

[0056] This example provides a method for rapid extraction and detection of declone in sediment. Preparation of sediment samples: The samples were freeze-dried, ground, and sieved (0.25 mm). The dry matter content of the sediment samples was determined according to GB17378.5. The remaining experimental steps were the same as in Example 1. The sample determination results, spiked recovery rate, relative standard deviation, etc. are shown in Table 4.

[0057] Table 4 Experimental results of actual sediment samples

[0058]

[0059] As shown in Table 4, cis-Declone was not detected in the sediment sample, the concentration of trans-Declone was 0.04 μg / kg, and the recoveries of cis-Declone and trans-Declone at three concentrations were 91.0%-100% and 101%-108%, respectively, and the relative standard deviations were 2.22%-4.47% and 3.43%-5.07%, respectively. The results show that the method of the present invention has a high recovery rate and good precision for the determination of Declone in sediments, and can meet the requirements for the determination of Declone content in sediments.

[0060] In summary, the method of the present invention is used to detect Declone in soil and sediment, with high extraction efficiency, easy operation, low detection limit, high accuracy and precision, and fully meets the needs of analyzing large quantities of actual samples.

[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for rapid extraction and detection of declone in soil and sediment, characterized in that: The following steps are involved: (1) Rapid extraction: Add soil or sediment into a centrifuge tube, then add the substitute solution, adsorbent and organic mixed solvent respectively for extraction and shaking, and then pass through anhydrous sodium sulfate to obtain the extract; (2) Purifying the extract: Purify the extract through a glass chromatography column, collect and concentrate the eluent, and add an internal standard solution to obtain the sample solution to be tested; (3) Preparation of standard curve: prepare at least five concentrations of cis-Declone and trans-Declone standard working solutions; (4) Determination and result analysis: The cis-Declone and trans-Declone standard working solutions of each concentration gradient in step (3) are measured by gas chromatography-triple quadrupole mass spectrometry, and the ratio of the target concentration to the internal standard compound concentration is used as the horizontal coordinate, and the ratio of the response value of the target quantitative ion pair to the response value of the internal standard compound quantitative ion pair is used as the vertical coordinate. Regression analysis is performed to obtain the cis-Declone and trans-Declone standard working curves; under the same conditions, the sample solution to be tested obtained in step (2) is measured by gas chromatography-triple quadrupole mass spectrometry to measure the response values ​​of the characteristic ions of cis-Declone and trans-Declone in the sample solution, and substitute them into the corresponding standard working curves to obtain the cis-Declone and trans-Declone contents in the sample solution, and then the Declone content in the soil or sediment sample is calculated based on the mass of the sample represented by the sample solution.

2. The method for rapid extraction and detection of decloaking in soil and sediment according to claim 1, characterized in that: In the step (1), the substitute solution is 13 C-Declon-602, the adsorbent is selected from any one of diatomaceous earth, N-propylethylenediamine solid phase adsorbent, and Mg / Al layered double metal hydroxide, and the organic mixed solvent is selected from any one of an acetone / n-hexane mixed solution with a volume ratio of 1:1, a dichloromethane / n-hexane mixed solution with a volume ratio of 1:1, and an acetone / dichloromethane mixed solution with a volume ratio of 1:

1.

3. The method for rapid extraction and detection of decloaking in soil and sediment according to claim 2, characterized in that: In the step (1), the substitute solution is 13 C-Declone-602, the adsorbent is Mg / Al layered double hydroxide, and the organic mixed solvent is a dichloromethane / n-hexane mixed solution with a volume ratio of 1:

1.

4. The method for rapid extraction and detection of decloaking in soil and sediment according to claim 1, characterized in that: In the step (1), the extraction oscillation time is 10 min to 30 min.

5. The method for rapid extraction and detection of decloaking in soil and sediment according to claim 1, characterized in that: In the step (2), the organic solvent is selected from any one of n-hexane, dichloromethane and acetone.

6. The method for rapid extraction and detection of decloaking in soil and sediment according to claim 1, characterized in that: In step (2), the specific process of glass chromatography column purification is as follows: the extract is passed through the glass chromatography column, eluted with 20 mL of organic solvent at a elution rate of 2 mL / min, the eluent is collected, concentrated to 1 mL by nitrogen blowing, and an internal standard is added. 13 C-PCB-209 solution was then used to obtain the test solution.

7. The method for rapid extraction and detection of decloaking in soil and sediment according to claim 1, characterized in that: In the step (4), the gas chromatograph operating conditions of the gas chromatograph-triple quadrupole mass spectrometer are: injection port temperature: 280°C; splitless injection, high pressure injection, pressure 150 kPa; injection volume: 1.0 μL; Chromatographic column: DB-5MS, specification: 15m×0.25 mm×0.1 μm; column box temperature: 100℃ for 1 min, increase to 310℃ at 20℃ / min, and maintain for 2 min; carrier gas mode: constant flow 1.5 mL / min.

8. The method for rapid extraction and detection of decloaking in soil and sediment according to claim 1, characterized in that: In the step (4), the operating conditions of the triple quadrupole mass spectrometer of the gas chromatography-triple quadrupole mass spectrometer are: electron bombardment source; ion source temperature of 280°C; ionization energy of 70 eV; transfer line temperature of 300°C; multiple reaction monitoring; and solvent delay of 3.5 min.

9. The method for rapid extraction and detection of decloaking in soil and sediment according to claim 1, characterized in that: In the step (2), the preparation process of the glass chromatography column is as follows: a small ball of quartz wool is placed at the bottom of the glass chromatography column, and 1 g of anhydrous sodium sulfate, 4 g of silica gel, 2 g of Florisil and 1 g of anhydrous sodium sulfate are filled in sequence to obtain a glass chromatography column.

10. The method for rapid extraction and detection of decloaking in soil and sediment according to claim 1, characterized in that: Before the soil or sediment in step (1) is subjected to oscillation extraction, foreign matter such as branches, leaves, and stones are removed, and the soil or sediment is freeze-dried, ground, and sieved.

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