Method for rapidly detecting typical halogenated organic pollutants in aquatic plants

Abstract

The invention relates to the technical field of pollutant analysis and identification, and discloses a method for rapidly detecting typical halogenated organic pollutants in aquatic plants. According to the method provided by the invention, synchronous detection of various volatile halogenated organic matters including trichloromethane, dichloromethane monobromide, monochloromethane dibromide, tribromomethane, dichloroacetaldehyde, trichloroacetaldehyde, dichloroacetonitrile, dibromoacetonitrile and trichloronitromethane can be realized at one time, so that the detection efficiency is greatly improved; the possibility is provided for rapid screening and quantitative analysis of complex and diversified halogenated pollutants in plants. The method provided by the invention is a detection means for volatile halogenated organic pollutants in plants, and has the characteristics of simplicity, convenience and rapidness in operation, lower detection limit, high sensitivity and excellent linear correlation, and ensures that the measurement result is accurate.

Description

Technical Field

[0001] The invention relates to the technical field of pollutant analysis and identification, and in particular to a method for rapidly detecting typical halogenated organic pollutants in aquatic plants. Background Art

[0002] The safety of sewage discharge is crucial to ensure safe drinking water for residents and maintain a stable ecological environment. The tailwater discharged from sewage treatment plants into rivers contains a series of halogenated organic pollutants (such as halogenated disinfection by-products). The lipophilicity of these pollutants makes them have significant biological toxicity and potential bioaccumulation, posing risks to human health and serious threats to the ecosystem. In addition, the ecological risk entropy values ​​of some volatile disinfection by-products (such as haloacetonitriles and haloacetic acids) exceed those of personal care products and endocrine disruptors.

[0003] At present, the determination technology for halogenated organic pollutants is mainly concentrated in the field of water bodies. For example, USEPA 551.1 and USEPA 552.3 have formulated standard methods for detecting common disinfection by-products in drinking water. Application No. 201810391533.5 discloses a method for simultaneously detecting 6 chlorophenylacetonitriles in drinking water, and Application No. 201710560481.5 discloses a method for simultaneously detecting 8 disinfection by-products including 4 halogenated acetonitriles.

[0004] However, there are relatively few studies on the detection of halogenated organic pollutants in organisms. Although some studies (Lee, WN; Huang, CH; Zhu, G., Analytical methods for conventional and emerging disinfection by-products in fresh-cut produce [J], Food Chemistry, 2019, 291: 30-37.) have disclosed a method for detecting disinfection by-products in fresh-cut vegetables based on gas chromatography electron capture detector, this method requires a large amount of plant (10g) and has a high minimum detection limit (0.3-10ng / g).

[0005] Given that halogenated organic matter in plants may be metabolized and decomposed, reducing the detection limit is of great significance for a deeper understanding of the changes of halogenated organic matter in plants. Application No. 202410917094.2 discloses a rapid detection method for aromatic nitrogen-containing disinfection byproducts in biological tissues, but due to the weak volatility of aromatic disinfection byproducts, this method uses nitrogen blowing for concentration and enrichment, which is not suitable for highly volatile halogenated organic pollutants.

[0006] Application No. 202410932557.2 discloses a method for detecting 12 disinfection by-products in fish meat based on gas chromatography-tandem electron capture detector. This method can avoid interference from non-halogen substances, but it is only qualitatively determined by retention time, which makes it difficult to accurately identify the types of halogenated organic pollutants under complex mechanisms. Therefore, it is particularly important to establish a method for accurately analyzing halogenated organic pollutants. In addition, the main interfering impurities in fish and plants are different, and chlorophyll in plants is the main influencing factor. The fish method is difficult to apply to pollutant detection in plants.

[0007] As an important part of the water environment, aquatic plants play an important role in the balance of ecological health in terms of the absorption, transformation and toxicity mechanism of halogenated organic pollutants, but the contribution of plants to halogenated organic matter and the related mechanism are still unclear. Detecting the content of halogenated organic pollutants in plants can help us gain a deeper understanding of the absorption and transformation mechanism of halogenated organic pollutants by plants. However, the complex plant matrix, low concentration of volatile halogenated organic matter, low boiling point and volatility make the detection technology face many challenges. Summary of the invention

[0008] The purpose of the present invention is to provide a method for rapidly detecting typical halogenated organic pollutants in aquatic plants based on the above technical problems.

[0009] In order to achieve the above object, the first aspect of the present invention provides a method for rapidly detecting typical halogenated organic pollutants in aquatic plants, the method comprising the following steps:

[0010] (1) grinding aquatic plants, internal standard substances, sodium chloride, anhydrous sodium sulfate, and volatile halogenated organic pollutants to obtain intermediate I;

[0011] (2) adding 0.5-1 mL of methyl tert-butyl ether to the intermediate I for a first extraction treatment to obtain supernatant I and intermediate I-1; adding 0.5-1 mL of methyl tert-butyl ether to the intermediate I-1 for a second extraction treatment to obtain supernatant II and intermediate I-2; adding 0.5-1 mL of methyl tert-butyl ether to the intermediate I-2 for a third extraction treatment to obtain supernatant III and intermediate I-3; adding 0.5-1 mL of methyl tert-butyl ether to the intermediate I-3 for a fourth extraction treatment to obtain supernatant IV and intermediate I-4;

[0012] (3) combining the above supernatants I, II, III, and IV, adding saturated sodium bicarbonate solution thereto, shaking at 1800-2800 rpm for 4-10 min, letting stand for 4-10 min, and taking supernatant V;

[0013] (4) Add a purifier to the supernatant V, shake at 1800-2800 rpm, and then centrifuge at 3000-5000 rpm for 3-10 min, take the supernatant VI, filter it using a nylon filter membrane with a pore size of 0.22 um, take the filtrate and place it in an injection bottle, and transfer it to GC-MS to detect volatile halogenated organic pollutants.

[0014] Preferably, in step (1), the amount of the aquatic plant used is 0.5 to 1.5 g, preferably 1 g, fresh weight.

[0015] Preferably, in step (1), the internal standard is selected from at least one of decafluorobiphenyl, deuterated acetonitrile and 1,1,1-trichloropropane.

[0016] More preferably, in step (1), the internal standard is preferably decafluorobiphenyl, and the amount of decafluorobiphenyl used is 50 ng relative to 1 g of the aquatic plant.

[0017] Preferably, in step (1), the amount of sodium chloride used is 0.2-0.5 g relative to 1 g of the aquatic plant; the amount of anhydrous sodium sulfate used is 0.2-0.5 g relative to 1 g of the aquatic plant.

[0018] Further preferably, in step (2), the first extraction treatment, the second extraction treatment, the third extraction treatment, and the fourth extraction treatment are first shaken at 1800-2800 rpm for 4-10 min, then ultrasonicated for 5-15 min, and then centrifuged at 3000-5000 rpm for 3-10 min.

[0019] Preferably, in step (3), the amount of the saturated sodium bicarbonate solution is 0 to 5 mL, preferably 2 mL.

[0020] Preferably, in step (4), the volume of the supernatant VI is 1.6 to 2 mL.

[0021] More preferably, in step (4), the purifier is at least one of graphitized carbon, N-propylethylenediamine, and neutral alumina, preferably graphitized carbon.

[0022] Preferably, in step (4), the amount of the purifier used is 50-150 mg, preferably 100 mg.

[0023] According to a preferred embodiment, in step (4), the parameters in the GC-MS are set as follows:

[0024] Chromatographic column: Rtx-5MS (length 30.0m, film thickness 0.25um, inner diameter 0.25um);

[0025] Carrier gas: high purity helium;

[0026] Carrier gas flow control method: linear speed control;

[0027] Carrier gas linear velocity: 30.0 cm / sec;

[0028] Injection method: splitless injection;

[0029] Inlet temperature: 180°C;

[0030] Ion source temperature: 200°C;

[0031] Interface temperature: 250℃;

[0032] Collection method: SIM;

[0033] Injection volume: 2 μL;

[0034] Column temperature: The initial temperature was 32°C and maintained at this temperature for 10 min; then increased to 80°C at a rate of 3°C / min; then increased to 240°C at a rate of 40°C / min and maintained at this temperature for 5 min.

[0035] Preferably, the volatile halogenated organic pollutants are chloroform, bromodichloromethane, dibromochloromethane, bromomethane, dichloroacetaldehyde, trichloroacetaldehyde, dichloroacetonitrile, dibromoacetonitrile, and chloropicrin.

[0036] The method provided by the present invention has at least the following beneficial effects:

[0037] (1) The method provided by the present invention is a detection method for volatile halogenated organic pollutants in plants, which is characterized by simple and quick operation, low detection limit, high sensitivity and excellent linear correlation, ensuring accurate measurement results. In view of the many difficulties in detection of volatile halogenated organic compounds due to their low concentration, low boiling point and high volatility, the present invention effectively fills the gap in the current field for efficient and accurate detection of such pollutants, and provides strong technical support for in-depth exploration of the migration path and transformation mechanism of halogenated organic compounds in plants.

[0038] (2) The method provided by the present invention can realize the simultaneous detection of various volatile halogenated organic compounds including chloroform, bromodichloromethane, dibromochloromethane, bromoform, dichloroacetaldehyde, trichloroacetaldehyde, dichloroacetonitrile, dibromoacetonitrile and chloropicrin at one time, which greatly improves the detection efficiency and provides the possibility for rapid screening and quantitative analysis of complex and diverse halogenated pollutants in plants.

[0039] (3) The method provided by the present invention uses gas phase mass spectrometry technology to achieve synchronous and sensitive detection of 9 volatile halogenated organic compounds, with a detection limit as low as 0.13-2.55 ng, showing excellent sensitivity and good reproducibility. This method is not only suitable for the detection needs of various types of plants, but also has a wide range of applicability, laying a solid foundation for future in-depth research in the fields of environmental science, ecology and food safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is the standard curve of chloroform, the target halogenated organic pollutant of the present invention;

[0041] Figure 2 is the standard curve of bromodichloromethane, the target halogenated organic pollutant of the present invention;

[0042] Figure 3 is the standard curve of dibromochloromethane, the target halogenated organic pollutant of the present invention;

[0043] Figure 4 is the standard curve of bromoform, the target halogenated organic pollutant of the present invention;

[0044] Figure 5 is the standard curve of the target halogenated organic pollutant dichloroacetaldehyde of the present invention;

[0045] Figure 6 is the standard curve of the target halogenated organic pollutant chloroacetaldehyde of the present invention;

[0046] Figure 7 is the standard curve of the target halogenated organic pollutant dichloroacetonitrile of the present invention;

[0047] Figure 8 is the standard curve of the target halogenated organic pollutant dibromoacetonitrile of the present invention;

[0048] Fig. 9 is the standard curve of the target halogenated organic pollutant chloropicrin of the present invention;

[0049] Fig.10 is a gas chromatogram of the target halogenated organic pollutant of the present invention;

[0050] Fig.11 is a diagram of optimization parameters of the method of the present invention;

[0051] Fig.12 It is a schematic flow chart of the method of the present invention. DETAILED DESCRIPTION

[0052] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0053] In the present invention, the amount of extraction solvent is an important technical feature. If the amount of the extraction solvent is too much, the target substance in the solvent will decrease, which is not easy to detect by instruments; if the amount of the extraction solvent is too little, the ground plant sample cannot be immersed, and it is not conducive to the purification process. The inventors of the present invention found in the experimental process that when the amount of the extraction solvent is 1.5±0.5mL, the extraction solvent can not only completely immerse the sample to ensure the extraction effect, but also save the amount of extraction solvent to ensure the concentration of the target substance in the extraction solvent.

[0054] In the present invention, the number of extractions is an important technical feature. The inventors of the present invention found in the experimental process that when the number of extractions is 2 to 4 times, the recovery rate of the target substance can be significantly increased compared to a single extraction, and the detection limit of the target substance can be reduced.

[0055] Due to the large number of plant matrices and the large number of extracted impurities, direct sampling may affect the response of the target substance, the peak time, and even damage the instrument, so purification is essential. In the present invention, the inventors of the present invention first use saturated sodium bicarbonate solution to remove water-soluble co-extracts during the experiment. In the collected extraction supernatant, 0mL and 2mL of saturated sodium bicarbonate were added, shaken, and the upper organic matter was taken again. It was found that the retention time of the nutrient without the addition of saturated sodium bicarbonate solution was moved forward, which greatly affected the detection of chloroform with the earliest peak time. The retention time of the sample with saturated sodium bicarbonate added was similar to that of the standard sample. Therefore, it was finally determined to add 2mL of saturated sodium bicarbonate solution. In addition, pigment is also a factor that has a great influence in this experiment. This experiment selects one or more of the commonly used purifiers graphitized carbon, N-propylethylenediamine, and neutral alumina, with a dosage of 150 mg, and directly adds them to a 50 μg / L standard dissolved in methyl tert-butyl ether. The recovery rate of graphitized carbon for the target substance is between 95% and 116%. Finally, graphitized carbon is selected as the purifier and added to the standard.

[0056] In the present invention, the amount of the purifier is an important technical feature. The inventors of the present invention found in the experiment that when the amount of the purifier is 50 to 150 mg, impurities such as pigments can be effectively removed and detection interference can be reduced.

[0057] In the present invention, the selection of the internal standard needs to ensure that the properties are similar to those of the target substance and that it has good instrument response and stability. In the present invention, decafluorobiphenyl, deuterated acetonitrile, and 1,1,1-trichloropropane are used for experiments, respectively. Among them, deuterated acetonitrile has a low response in GC-MS detection, and 1,1,1-trichloropropane has poor stability in organic solutions, which is not conducive to repeated detection of samples. Finally, decafluorobiphenyl with good instrument response and strong stability is selected as the internal standard.

[0058] In the present invention, by adjusting the initial temperature, holding time and heating rate of the GC-MS heating program, and comparing the peak time, chromatographic peak separation, peak height and peak area of ​​the target halogenated organic pollutants, the following heating program is obtained: the initial temperature is 32°C, maintained for 10 minutes; then increased to 80°C at a rate of 3°C / min; increased to 240°C at a rate of 40°C / min, maintained for 5 minutes. The inventors of the present invention have found that under this heating program, the target halogenated organic pollutants can be guaranteed to have normal peaks and good peak shapes.

[0059] In the present invention, in order to ensure that impurities in plants reduce interference with the detection of target halogenated organic pollutants, fragment ions with stable responses and no interference from impurities are selected. In the actual experimental process, the inventors of the present invention compared the response of each target halogenated organic pollutant fragment ion and the spike recovery, and determined one fragment ion as the target ion and two fragment ions as reference ions to assist in qualitative analysis.

[0060] In the present invention, other conditions of GC-MS are controlled to remain unchanged, and the injection volume is set to 1 μL, 2 μL, and 3 μL respectively. For the injection volume, only integer settings can be performed in GC-MS, and the size of the injection volume will affect the peak time of the substance. The peak area and peak time of the corresponding substance are examined, and the injection volume is compared to be not less than 2 μL. When it is less than 2 μL, the obtained peak area is too small, which is not conducive to the detection of target halogenated organic pollutants, and the peak time is moved forward, which is not conducive to the detection of substances with early peak times such as chloroform.

[0061] In the present invention, there is no special requirement for the grinding treatment conditions in step (1), which only needs to be ground into a homogenous state. Exemplarily, manual grinding is used.

[0062] The present invention will be described in detail below by way of examples. In the following examples, unless otherwise specified, the raw materials are all commercially available.

[0063] In the optimization experiment of multiple solid-liquid extraction parameters, chloroform, bromodichloromethane, dibromochloromethane, bromoform, dichloroacetaldehyde, trichloroacetaldehyde, dichloroacetonitrile, dibromoacetonitrile, and trichloropicrin standards were used to determine the recovery of the target analyte under different experimental conditions. Take an appropriate amount of standard and dissolve it in an organic solvent to prepare a mixed solution of standard for subsequent recovery detection. Use an organic solvent to dilute the target analyte and the internal standard substance to different concentrations to establish a standard curve. Prepare a sample with a concentration of 50 ng / g, determine the target concentration after multiple solid-liquid extraction pretreatment, and the recovery is determined according to the following formula. The schematic diagram of the multiple solid-liquid extraction operation process is shown in the figure. Fig.12 shown.

[0064]

[0065] Preparation Example 1

[0066] This example is used to establish a standard curve, specifically, including the following steps:

[0067] S1: Take 10 μL (1000 mg / L) of a mixed standard solution of chloroform, bromodichloromethane, dibromochloromethane and bromoform, and take 10 μL of dichloroacetaldehyde standard solution (1000 mg / L), 10 μL of trichloroacetaldehyde standard solution (1000 mg / L), 10 μL of dichloroacetonitrile standard solution (1000 mg / L), 10 μL of dibromoacetonitrile standard solution (1000 mg / L), and 100 μL of trichloropicrin standard solution (100 mg / L), respectively, and dissolve them in 850 μL of methyl tert-butyl ether to make a mixed standard solution with a concentration of 10 μg / mL and place them in brown bottles I respectively.

[0068] S2: Weigh 0.1 g of decafluorobiphenyl, add it to 100 mL of methyl tert-butyl ether, prepare a storage solution with an initial concentration of 1 g / L, and place it in a brown bottle II. Take 10 μL of the storage solution from the brown bottle II and dissolve it in 990 μL of methyl tert-butyl ether to prepare a standard solution of 10 μg / mL, and place it in a brown bottle III.

[0069] S3: Take 0.5 μL, 1 μL, 2 μL, 5 μL, 8 μL, 10 μL, 12 μL, and 15 μL of the mixed standard solution from the brown bottle I, respectively, dissolve them in 994.5 μL, 994 μL, 993 μL, 990 μL, 987 μL, 985 μL, 983 μL, and 980 μL of methyl tert-butyl ether, respectively, and add 5 μL of the standard solution in the brown bottle III, respectively, to prepare gradient standard calibration solutions with a volume of 1 mL and gradient mass concentrations of 5 μg / L, 10 μg / L, 20 μg / L, 50 μg / L, 80 μg / L, 100 μg / L, 120 μg / L, and 150 μg / L, respectively, which are recorded as gradient standard calibration solution 1 to gradient standard calibration solution 9;

[0070] Relative to 1g of aquatic plants, the concentration of the gradient standard correction solution 1 is 5ng / g, the concentration of the gradient standard correction solution 2 is 10ng / g, the concentration of the gradient standard correction solution 3 is 20ng / g, the concentration of the gradient standard correction solution 4 is 50ng / g, the concentration of the gradient standard correction solution 5 is 80ng / g, the concentration of the gradient standard correction solution 6 is 100ng / g, the concentration of the gradient standard correction solution 7 is 120ng / g, and the concentration of the gradient standard correction solution 8 is 150ng / g.

[0071] S4: The above-mentioned gradient standard calibration solution is batch analyzed by gas chromatography / mass spectrometry, and the standard curves of the target halogenated organic pollutants are generated by 1absolution workstation, such as Figures 1 to 9 shown.

[0072] in, Fig.10 is the measured gas chromatogram. Fig.10 It can be seen that the elution time of chloroform is 3.84min; the elution time of monobromodichloromethane is 5.665min; the elution time of dibromochloromethane is 10.125min; the elution time of bromoform is 16.540min; the elution time of dichloroacetaldehyde is 4.030min; the elution time of trichloroacetaldehyde is 5.895min; the elution time of dichloroacetonitrile is 4.820min; the elution time of dibromoacetonitrile is 18.860min; the elution time of trichloropicrin is 9.160min; and the elution time of decafluorobiphenyl is 28.100min.

[0073] Table 1

[0074]

[0075]

[0076] As shown in Table 1, the detection method of the present invention enables the target halogenated organic pollutants to be well separated during the analysis process, and the linearity is good in the range of 5 to 150 ng / g (R 2 >0.99), and the method detection limit (MDL) was 0.13~2.55ng / g.

[0077] Preparation Example 2

[0078] S1: Take 10 μL (1000 mg / L) of a mixed standard solution of chloroform, bromodichloromethane, dibromochloromethane, and bromoform, and take 10 μL of dichloroacetaldehyde standard solution (1000 mg / L), 10 μL of trichloroacetaldehyde standard solution (1000 mg / L), 10 μL of dichloroacetonitrile standard solution (1000 mg / L), 10 μL of dibromoacetonitrile standard solution (1000 mg / L), and 100 μL of trichloropicrin standard solution (100 mg / L) respectively, dissolve them in 850 μL of methyl tert-butyl ether, prepare a mixed standard solution with a concentration of 10 μg / mL and place it in a brown bottle I.

[0079] S2: Take 50 μL of the mixed standard solution from the brown bottle I, add it to 10 mL of methyl tert-butyl ether to dissolve, then add 150 mg of graphitized carbon, shake at 2300 rpm for 5 min, centrifuge at 3000 rpm for 5 min, take the supernatant, filter it with a nylon filter membrane with a pore size of 0.22 um, and transfer it to GC-MS for detection. The results are shown in Table 2.

[0080] Preparation Example 3

[0081] The method in Preparation Example 2 was followed, except that the same amount of N-propylethylenediamine was used to replace the graphitized carbon, and the remaining steps and methods were the same as in Preparation Example 2.

[0082] Preparation Example 4

[0083] The method in Preparation Example 2 was followed, except that the same amount of neutral alumina was used to replace the graphitized carbon, and the remaining steps and methods were the same as in Preparation Example 2.

[0084] Preparation Example 5

[0085] The method in Preparation Example 2 was followed, except that 75 mg of neutral alumina and 75 mg of graphitized carbon were used, and the remaining steps and methods were the same as in Preparation Example 2.

[0086] Preparation Example 6

[0087] The method in Preparation Example 2 was followed, except that 75 mg of N-propylethylenediamine and 75 mg of graphitized carbon were used, and the remaining steps and methods were the same as those in Preparation Example 2.

[0088] Preparation Example 7

[0089] The method in Preparation Example 2 was followed, except that 75 mg of N-propylethylenediamine and 75 mg of neutral alumina were used. The remaining steps and methods were the same as in Preparation Example 2.

[0090] Table 2

[0091]

[0092] As shown in Table 2, the recovery rate of graphitized carbon for the target halogenated polluted organic matter is within 95-116%, which has a good recovery effect and will not bring in other impurities to affect the detection.

[0093] Example 1

[0094] This example is used to provide a combination Fig.12 A method for detecting volatile halogenated organic pollutants in plants based on multiple solid-liquid extractions is described, the method comprising the following steps:

[0095] (1) 0.2 g of sodium chloride, 0.2 g of anhydrous sodium sulfate, 1 g of fresh weight of copper coin grass, 9 halogenated organic pollutants, and decafluorobiphenyl were manually ground into a homogenous state to obtain intermediate I; relative to 1 g of the copper coin grass, the amount of the 9 halogenated organic pollutants was 50 ng; relative to 1 g of the copper coin grass, the amount of the decafluorobiphenyl was 50 ng.

[0096] (2) adding 1 mL of methyl tert-butyl ether to the intermediate I for the first extraction treatment to obtain supernatant I and intermediate I-1; adding 500 μL of methyl tert-butyl ether to the intermediate I-1 for the second extraction treatment to obtain supernatant II and intermediate I-2; adding 500 μL of methyl tert-butyl ether to the intermediate I-2 for the third extraction treatment to obtain supernatant III and intermediate I-3; adding 500 μL of methyl tert-butyl ether to the intermediate I-3 for the fourth extraction treatment to obtain supernatant IV and intermediate I-4;

[0097] The first extraction treatment, the second extraction treatment, the third extraction treatment and the fourth extraction treatment are firstly shaken at 2300 rpm for 5 minutes, then ultrasonicated for 10 minutes, and then centrifuged at 3000 rpm for 5 minutes.

[0098] (3) The supernatant I, supernatant II, supernatant III, and supernatant IV were combined, and 2 mL of saturated sodium bicarbonate solution was added thereto. The mixture was then shaken at 2300 rpm for 5 min, allowed to stand for 5 min, and supernatant V was collected.

[0099] (4) 100 mg of graphitized carbon was added to 1.8 mL of the supernatant V, shaken at 2300 rpm for 5 min, and then centrifuged at 3000 rpm for 5 min. The supernatant VI was taken and filtered using a nylon filter membrane with a pore size of 0.22 μm. The filtrate was placed in a 1.5 mL injection bottle and transferred to GC-MS for detection. The results are shown in Table 4;

[0100] The parameters in the GC-MS were set as follows:

[0101] Chromatographic column: Rtx-5MS (length 30.0m, film thickness 0.25um, inner diameter 0.25um);

[0102] Carrier gas: high purity helium;

[0103] Carrier gas flow control method: linear speed control;

[0104] Carrier gas linear velocity: 30.0 cm / sec;

[0105] Injection method: splitless injection;

[0106] Inlet temperature: 180°C;

[0107] Ion source temperature: 200°C;

[0108] Interface temperature: 250℃;

[0109] Collection method: SIM;

[0110] Injection volume: 2 μL;

[0111] Column temperature: Initial temperature was 32°C and maintained at this temperature for 10 min; then increased to 80°C at a rate of 3°C / min; increased to 240°C at a rate of 40°C / min and maintained at this temperature for 5 min;

[0112] Among them, the target halogenated organic pollutant fragment ion selection is shown in Table 3.

[0113] Table 3

[0114] Target halogenated organic pollutants Target ion m / z Reference ion 1m / z Reference ion 2m / z Chloroform 83 85 47 Bromodichloromethane 83 85 47 Dibromochloromethane 129 127 131 Bromoform 173 171 175 Dichloroacetaldehyde 49 48 84 Chloral 82 84 111 Dichloroacetonitrile 74 82 76 Dibromoacetonitrile 120 118 199 Chloropicrin 117 119 121 Decafluorobiphenyl 334 265 335

[0115] Table 4

[0116]

[0117]

[0118] As shown in Table 4, the recovery rates of the nine halogenated organic pollutants were between 74% and 124%, and the detection limits were between 0.75 and 34.96 ng / g. It can be seen that the detection method provided by the present invention has high sensitivity.

[0119] Example 2

[0120] The method in Example 1 was followed, except that in step (1), the same amount of Ceratophyllum exposed to a halogenated organic pollutant environment was used to replace the pennywort, and the 9 halogenated organic pollutants were not added. The remaining steps and methods were the same as in Example 1. The test results are shown in Table 5.

[0121] Table 5

[0122] Target halogenated organic pollutants Concentration (ng / g) Standard Deviation Chloroform 127.48 3.45 Bromodichloromethane <LOD - Dibromochloromethane <LOD - Bromoform <LOD - Dichloroacetaldehyde <LOD - Chloral 5.81 0.70 Dichloroacetonitrile <LOD - Dibromoacetonitrile <LOD - Chloropicrin <LOD -

[0123] As shown in Table 5, 2 out of 9 halogenated organic pollutants were detected in Ceratophyllum, and the standard deviations were all lower than 3.45. It can be seen that the detection method of the present invention has high sensitivity and has good detection effects in different types of plants.

[0124] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for rapid detection of typical halogenated organic pollutants in aquatic plants, characterized in that: The method comprises the following steps: (1) grinding aquatic plants, internal standard substances, sodium chloride, anhydrous sodium sulfate, and volatile halogenated organic pollutants to obtain intermediate I; (2) adding 0.5-1 mL of methyl tert-butyl ether to the intermediate I for a first extraction treatment to obtain supernatant I and intermediate I-1; adding 0.5-1 mL of methyl tert-butyl ether to the intermediate I-1 for a second extraction treatment to obtain supernatant II and intermediate I-2; adding 0.5-1 mL of methyl tert-butyl ether to the intermediate I-2 for a third extraction treatment to obtain supernatant III and intermediate I-3; adding 0.5-1 mL of methyl tert-butyl ether to the intermediate I-3 for a fourth extraction treatment to obtain supernatant IV and intermediate I-4; (3) combining the above supernatants I, II, III, and IV, adding saturated sodium bicarbonate solution thereto, shaking at 1800-2800 rpm for 4-10 min, letting stand for 4-10 min, and taking supernatant V; (4) Add a purifier to the supernatant V, shake at 1800-2800 rpm, and then centrifuge at 3000-5000 rpm for 3-10 min, take the supernatant VI, filter it using a nylon filter membrane with a pore size of 0.22 um, take the filtrate and place it in an injection bottle, and transfer it to GC-MS to detect volatile halogenated organic pollutants.

2. The method according to claim 1, wherein: In step (1), the amount of the aquatic plant used is 0.5 to 1.5 g fresh weight, preferably 1 g.

3. The method according to claim 1 or 2, wherein: In step (1), the internal standard is selected from at least one of decafluorobiphenyl, deuterated acetonitrile, and 1,1,1-trichloropropane; And / or, in step (1), the internal standard is preferably decafluorobiphenyl, and the amount of decafluorobiphenyl used is 50 ng relative to 1 g of the aquatic plant.

4. The method according to claim 1 or 2, wherein: In step (1), the amount of sodium chloride used is 0.2-0.5 g relative to 1 g of the aquatic plant; the amount of anhydrous sodium sulfate used is 0.2-0.5 g relative to 1 g of the aquatic plant.

5. The method according to claim 1 or 2, wherein: In step (2), the first extraction treatment, the second extraction treatment, the third extraction treatment, and the fourth extraction treatment are first shaken at 1800-2800 rpm for 4-10 minutes, then ultrasonicated for 5-15 minutes, and then centrifuged at 3000-5000 rpm for 3-10 minutes.

6. The method according to claim 1 or 2, wherein: In step (3), the amount of the saturated sodium bicarbonate solution is 0 to 5 mL.

7. The method according to claim 1 or 2, wherein: In step (4), the volume of the supernatant VI is 1.6 to 2 mL.

8. The method according to claim 1 or 2, wherein: In step (4), the purifier is at least one of graphitized carbon, N-propylethylenediamine, and neutral alumina, preferably graphitized carbon; And / or, in step (4), the amount of the purifier used is 50-150 mg, preferably 100 mg.

9. The method according to claim 1 or 2, wherein: In step (4), the parameters in the GC-MS are set as follows: Chromatographic column: Rtx-5MS (length 30.0m, film thickness 0.25um, inner diameter 0.25um); Carrier gas: high purity helium; Carrier gas flow control method: linear speed control; Carrier gas linear velocity: 30.0 cm / sec; Injection method: splitless injection; Inlet temperature: 180°C; Ion source temperature: 200°C; Interface temperature: 250℃; Collection method: SIM; Injection volume: 2 μL; Column temperature: The initial temperature was 32°C and maintained at this temperature for 10 min; then increased to 80°C at a rate of 3°C / min; then increased to 240°C at a rate of 40°C / min and maintained at this temperature for 5 min.

10. The method according to claim 1 or 2, wherein the volatile halogenated organic pollutants are chloroform, bromodichloromethane, dibromochloromethane, bromomethane, dichloroacetaldehyde, trichloroacetaldehyde, dichloroacetonitrile, dibromoacetonitrile, and chloropicrin.

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