A method for rapid detection of typical halogenated organic pollutants in aquatic plants

Abstract

The present 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. The method provided by the present invention can simultaneously detect a variety of volatile halogenated organic compounds including chloroform, bromodichloromethane, dibromochloromethane, bromoform, dichloroacetaldehyde, trichloroacetaldehyde, dichloroacetonitrile, dibromoacetonitrile and chloropicrin at one time, greatly improving the detection efficiency and providing the possibility for rapid screening and quantitative analysis of complex and diverse halogenated pollutants in plants. The method provided by the present invention is a detection method for volatile halogenated organic pollutants in plants, which is characterized by being simple and quick to operate, having a low detection limit, high sensitivity and excellent linear correlation, and ensuring accurate measurement results.

Description

Technical Field

[0001] The present 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 wastewater discharge is crucial to ensuring safe drinking water for residents and maintaining a stable ecological environment. Wastewater treatment plant tailwaters discharged into rivers contain a range of halogenated organic pollutants (such as halogenated disinfection byproducts). The lipophilic nature of these pollutants makes them highly biotoxic and potentially bioaccumulative, posing risks to human health and a serious threat to ecosystems. Furthermore, the ecological risk entropy values ​​of some volatile disinfection byproducts (such as haloacetonitriles and haloacetic acids) exceed those of personal care products and endocrine disruptors.

[0003] Currently, the determination of halogenated organic pollutants is primarily focused on water. For example, USEPA 551.1 and USEPA 552.3 have established standard methods for detecting common disinfection byproducts in drinking water. Application No. 201810391533.5 discloses a method for the simultaneous detection of six chlorophenylacetonitriles in drinking water, while Application No. 201710560481.5 discloses a method for the simultaneous detection of eight disinfection byproducts, including four haloacetonitriles.

[0004] However, relatively little research has been conducted on the detection of halogenated organic pollutants in organisms. Although one study (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) has published a method for detecting disinfection by-products in fresh-cut vegetables using a gas chromatography electron capture detector, this method requires a large amount of plant material (10g) and has a high minimum detection limit (0.3-10ng / g).

[0005] Given that halogenated organic compounds in plants may be metabolized, lowering the detection limit is crucial for gaining a deeper understanding of their behavior in plants. Application No. 202410917094.2 discloses a rapid detection method for aromatic nitrogen-containing disinfection byproducts in biological tissues. However, due to the low volatility of aromatic disinfection byproducts, this method uses nitrogen purging for concentration and enrichment, making it unsuitable for highly volatile halogenated organic pollutants.

[0006] Application No. 202410932557.2 discloses a method for detecting 12 disinfection byproducts in fish meat based on gas chromatography-tandem electron capture detection. 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. Chlorophyll in plants is the main influencing factor. The fish method is difficult to apply to pollutant detection in plants.

[0007] Aquatic plants, as a vital component of the aquatic environment, play a crucial role in maintaining ecological health through the absorption, transformation, and toxicity of halogenated organic pollutants. However, the contribution of plants to halogenated organic compounds and the underlying mechanisms remain unclear. Measuring the levels of halogenated organic pollutants in plants can provide insights into their absorption and transformation mechanisms. However, the complex nature of plant matrices, the low concentrations of volatile halogenated organic compounds, their low boiling points, and their volatility present numerous challenges to detection techniques. 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, an internal standard, 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) Combine the above supernatants I, II, III, and IV, add saturated sodium bicarbonate solution, shake at 1800-2800 rpm for 4-10 minutes, let stand for 4-10 minutes, and collect 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 μm, take the filtrate and place it in an injection bottle, and transfer it to GC-MS for detection of volatile halogenated organic pollutants.

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

[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 to 0.5 g relative to 1 g of the aquatic plant; the amount of anhydrous sodium sulfate used is 0.2 to 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 minutes, then ultrasonicated for 5-15 minutes, and then centrifuged at 3000-5000 rpm for 3-10 minutes.

[0019] Preferably, in step (3), the amount of the saturated sodium bicarbonate solution is 0-5 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 scavenger 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 30.0 m, film thickness 0.25 μm, inner diameter 0.25 μm);

[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 means for detecting volatile halogenated organic pollutants in plants. It is characterized by its simple and rapid operation, low detection limit, high sensitivity, and excellent linear correlation, ensuring accurate measurement results. Given the numerous difficulties in detecting 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, providing strong technical support for in-depth exploration of the migration pathways and transformation mechanisms of halogenated organic compounds in plants.

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

[0039] (3) The method provided by this invention achieves simultaneous and sensitive detection of nine volatile halogenated organic compounds using gas chromatography-mass spectrometry, with detection limits as low as 0.13 to 2.55 ng, demonstrating excellent sensitivity and reproducibility. This method is not only applicable to the detection needs of various plant types, but also, due to its broad applicability, lays a solid foundation for future in-depth research in fields such as environmental science, ecology, and food safety. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

[0044] Figure 5 This 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 chloral of the present invention;

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

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

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

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

[0050] Figure 11 is a diagram of optimized parameters of the method of the present invention;

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

[0052] The endpoints of the ranges and any values ​​disclosed herein 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 endpoints of each range, the endpoints of each range and 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 to be specifically disclosed herein.

[0053] In the present invention, the amount of extraction solvent used is an important technical feature. If the amount of the extraction solvent is too much, the concentration of the target substance in the solvent will decrease, making it difficult for the instrument to detect; if the amount of the extraction solvent is too little, it will not be able to immerse the ground plant sample and will be detrimental to the purification process. During the experiment, the inventors of the present invention found 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] The number of extractions is an important technical feature of the present invention. The inventors of the present invention have found during experiments that when the number of extractions is 2 to 4, 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 lowered.

[0055] Since there are many plant matrices and many 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 used a saturated sodium bicarbonate solution to remove water-soluble co-extracts during the experiment. 0mL and 2mL of saturated sodium bicarbonate were added to the collected extraction supernatant, shaken, and the upper organic matter was taken again. It was found that the retention time of the nutrient product without the addition of saturated sodium bicarbonate solution was shifted forward, which greatly affected the detection of chloroform with the earliest peak time. The retention time of the sample with the addition of saturated sodium bicarbonate 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 selected one or more of the commonly used purifiers graphitized carbon, N-propylethylenediamine, and neutral alumina, with a dosage of 150 mg, and directly added them to a 50 μg / L standard dissolved in methyl tert-butyl ether. The recovery rate of graphitized carbon for the target substance was between 95% and 116%. Finally, graphitized carbon was 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 during experiments that when the amount of the purifier is 50 to 150 mg, it can effectively remove impurities such as pigments and reduce detection interference.

[0057] In the present invention, the internal standard must be selected to ensure that its properties are similar to those of the target substance and that it has good instrument response and stability. In this study, experiments were conducted using decafluorobiphenyl, deuterated acetonitrile, and 1,1,1-trichloropropane. Deuterated acetonitrile has a low GC-MS response, and 1,1,1-trichloropropane has poor stability in organic solutions, making it difficult to perform repeated sample testing. Ultimately, decafluorobiphenyl was selected as the internal standard due to its good instrument response and strong stability.

[0058] In the present invention, by adjusting the initial temperature, hold time, and heating rate of the GC-MS temperature program and comparing the peak emission time, chromatographic peak resolution, peak height, and peak area of ​​the target halogenated organic pollutants, the following temperature program was developed: initial temperature 32°C, hold for 10 minutes; then increase to 80°C at a rate of 3°C / min; then increase to 240°C at a rate of 40°C / min, hold for 5 minutes. The inventors found that this temperature program ensures the normal emission of the target halogenated organic pollutants with a good peak shape.

[0059] In this study, 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 were selected. During actual experiments, the inventors compared the responses of each target halogenated organic pollutant fragment ion and the spike recovery, identifying one fragment ion as the target ion and two fragment ions as reference ions for auxiliary qualitative analysis.

[0060] In the present invention, other GC-MS conditions are controlled 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 injection volume size will affect the peak time of the substance. The peak area and peak time of the corresponding substance are examined, and the comparison shows that the injection volume is 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 shifted 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 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 through 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 standard mixed solution for subsequent recovery detection. Use an organic solvent to dilute the target analyte and the internal standard substance to different concentrations and establish a standard curve. Prepare a sample with a concentration of 50 ng / g, and determine the target concentration after multiple solid-liquid extraction pretreatment. The recovery rate is determined according to the following formula. The schematic diagram of the multiple solid-liquid extraction operation process is as follows: Figure 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 chloropicrin 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 bottle I respectively.

[0068] S2: Weigh 0.1 g of decafluorobiphenyl and add it to 100 mL of methyl tert-butyl ether to prepare a stock solution with an initial concentration of 1 g / L, and place it in a brown bottle II. Take 10 μL of the stock solution from the brown bottle II and dissolve it in 990 μL of methyl tert-butyl ether to prepare a 10 μg / mL standard solution, 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, and 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 gradient standard calibration solutions were batch analyzed by gas chromatography / mass spectrometry, and the standard curves of the target halogenated organic pollutants were generated by 1absolution workstation, such as Figures 1 to 9 shown.

[0072] in, Figure 10 is the gas chromatogram obtained. Figure 10 It can be seen that the elution time of chloroform is 3.84min; the elution time of bromodichloromethane 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 chloropicrin 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, with good linearity (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 chloropicrin 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 it in 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 through a nylon filter membrane with a pore size of 0.22 μm, 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. The remaining steps and methods were the same as those 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. The remaining steps and methods were the same as those in Preparation Example 2.

[0088] Preparation Example 7

[0089] The method of 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 those of Preparation Example 2.

[0090] Table 2

[0091]

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

[0093] Example 1

[0094] This example is used to provide a combination Figure 12 A method for detecting volatile halogenated organic pollutants in plants based on multiple solid-liquid extractions is described, 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 Herba, 9 halogenated organic pollutants, and decafluorobiphenyl were manually ground into a homogenous state to obtain intermediate I; relative to 1 g of Copper Coin Herba, the amount of the 9 halogenated organic pollutants was 50 ng; relative to 1 g of Copper Coin Herba, 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 first shaking at 2300 rpm for 5 minutes, then ultrasonicating for 10 minutes, and then centrifuging at 3000 rpm for 5 minutes.

[0098] (3) Combine the supernatant I, supernatant II, supernatant III, and supernatant IV, add 2 mL of saturated sodium bicarbonate solution, shake at 2300 rpm for 5 min, let it stand for 5 min, and take supernatant V.

[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 30.0 m, film thickness 0.25 μm, inner diameter 0.25 μm);

[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; then 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 ions are selected as shown in Table 3.

[0113] Table 3

[0114] Target halogenated organic pollutants Target ion m / z Reference ion 1 m / z Reference ion 2 m / 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 recoveries of the nine halogenated organic pollutants were between 74% and 124%, and the detection limits were between 0.75 and 34.96 ng / g. This shows 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 demersum exposed to a halogenated organic pollutant environment was used instead of the pennywort, and the nine 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 of the 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 plant species.

[0124] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection 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, an internal standard, sodium chloride, anhydrous sodium sulfate, and volatile halogenated organic pollutants to obtain intermediate I; the volatile halogenated organic pollutants are chloroform, bromodichloromethane, dibromochloromethane, bromomethane, dichloroacetaldehyde, trichloroacetaldehyde, dichloroacetonitrile, dibromoacetonitrile, and chloropicrin; (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) Combine the above supernatants I, II, III, and IV, add saturated sodium bicarbonate solution, shake at 1800-2800 rpm for 4-10 minutes, let stand for 4-10 minutes, and collect 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 μm, take the filtrate and place it in an injection bottle, and transfer it to GC-MS for detection of 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 in fresh weight.

3. The method according to claim 1, 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 amount of the internal standard is 50 ng per gram of aquatic plant.

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

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

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

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

9. The method according to claim 1, wherein: In step (4), the parameters in the GC-MS are set as follows: Chromatographic column model: Rtx-5MS; Column specifications: 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.

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