Convenient and ready-to-use solvent extraction rod and detection method thereof

Abstract

The invention belongs to the technical field of analysis and detection, and particularly relates to a convenient and ready-to-use solvent extraction rod and a detection method thereof. The invention provides a convenient and ready-to-use solvent extraction rod. The convenient and ready-to-use solvent extraction rod comprises a hollow rod and a fiber head, the hollow rod is provided with an open end and a closed end, and the hollow rod is filled with an extracting solvent; the fiber head is fixed at the opening end of the hollow rod; a breaking line is arranged on the pipe wall, close to the closed end, of the hollow rod; the extraction solvent is a deep eutectic solvent or ionic liquid; and the fiber head is made of a lipophilic fiber material. The convenient and ready-to-use solvent extraction rod can rapidly extract and enrich hydrophobic target objects in a large-volume aqueous sample, not only avoids complex extraction, separation and other operations in pretreatment, but also realizes lower detection limit and higher enrichment efficiency, greatly improves the sample pretreatment efficiency, meets the requirement of rapid monitoring, and has wide application prospects. And a new strategy can be provided for sample pretreatment and analysis detection of trace target objects in a large-volume aqueous sample.

Description

Technical Field

[0001] The present invention belongs to the technical field of analytical detection, and particularly relates to a convenient and ready-to-use solvent extraction rod and a detection method thereof. Background Art

[0002] In recent years, the threats of environmental pollution and organic pollutants to human health and the ecosystem have become increasingly severe. The complex chemical components and potential harmful substances contained in traditional Chinese medicine liquids, food and beverages, sewage, etc. have brought huge challenges to their quality control and safety assurance. Therefore, it has become an urgent task to develop efficient detection technologies applicable to harmful substances in complex matrices.

[0003] Pesticides such as triazole compounds are often used as fungicides to control pathogens in agricultural production due to their strong adsorption and persistence. However, the excessive or improper use of these pesticides may lead to environmental pollution and food safety problems, and some pesticide metabolites have high cytotoxicity, which also poses potential risks to human health. Therefore, in order to ensure that pesticide use is within an acceptable limit, it is crucial to monitor the residual levels of pesticide compounds.

[0004] For a long time, the traditional technologies that have been used for the analysis of pesticide compound residues mainly include high performance liquid chromatography (HPLC), gas chromatography (GC), liquid chromatography - mass spectrometry (LC - MS), etc. However, in view of the challenges brought by low - concentration pesticides and complex matrices, these detection methods often fail to achieve high sensitivity and accuracy. Therefore, researchers have tried to optimize the sample pretreatment process to simplify the operation, achieve environmental sustainability, improve analyte enrichment and detection sensitivity, so as to meet the requirements of trace pesticide detection.

[0005] However, although there are various extraction and detection pretreatment technologies in the analysis field, many methods still face challenges such as complex operation, dependence on laboratory environment, and difficulty in processing large - volume liquid samples such as traditional Chinese medicine decoctions, food and beverages, sewage, etc. These limitations not only reduce the detection efficiency but also hinder the wide application of these methods in practical applications.

[0006] Therefore, it is crucial to develop a simple, efficient, and environmentally friendly solvent extraction device and a matching detection method to meet the actual detection needs of trace target compounds in large - volume liquid samples. Summary of the Invention

[0007] Aiming at the deficiencies in the prior art, the purpose of the present invention is to provide a convenient and ready-to-use solvent extraction rod. Using this convenient and ready-to-use solvent extraction rod for the detection of target substances in large-volume aqueous samples can quickly extract and sensitively detect hydrophobic target substances (such as pesticides, etc.) in large-volume aqueous samples, and solve the problems that traditional detection equipment and detection processes are cumbersome, time-consuming, and costly, and cannot meet the requirements of efficient enrichment and efficient monitoring of target substances in large-volume aqueous samples.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A convenient and ready-to-use solvent extraction rod, comprising: a hollow rod and a fiber head; the hollow rod is provided with an open end and a closed end, and the hollow rod is filled with an extraction solvent; the fiber head is fixed at the open end of the hollow rod; the hollow rod is provided with a breaking line on the tube wall near the closed end; the extraction solvent is a deep eutectic solvent or an ionic liquid; the material of the fiber head is a lipophilic fiber material.

[0010] The present invention does not particularly limit the type of lipophilic fiber material, and those skilled in the art can conventionally select fiber types suitable for adsorbing hydrophobic target substances in aqueous samples. In a preferred embodiment of the present invention, the lipophilic fiber material is polypropylene fiber or polyester fiber.

[0011] In a preferred embodiment of the present invention, the material of the hollow rod is glass, plastic or other permitted materials.

[0012] The application of the above-mentioned convenient and ready-to-use solvent extraction rod, and the application is the application of the convenient and ready-to-use solvent extraction rod in the detection of target substances in aqueous samples.

[0013] A method for detecting target substances in aqueous samples using the above-mentioned convenient and ready-to-use solvent extraction rod, comprising the following steps:

[0014] (1) Prepare the convenient and ready-to-use solvent extraction rod, place the closed end of the hollow rod in the convenient and ready-to-use solvent extraction rod upward, and then break the hollow rod along the breaking line. The extraction solvent filled in the hollow rod is adsorbed on the fiber head by gravity.

[0015] (2) Immerse the fiber head adsorbed with the extraction solvent completely in the aqueous sample to be tested for extraction.

[0016] (3) Perform desorption treatment on the extracted fiber head with a desorption solvent, then collect the desorption solution and perform instrumental analysis to obtain the content of the target substance in the aqueous sample to be tested.

[0017] The present invention does not specifically limit the type of aqueous sample, and technicians can routinely select the type of sample to be tested. In a preferred embodiment of the present invention, in step (2), the aqueous sample to be tested is selected from one or more of traditional Chinese medicine liquid, food and beverage, and sewage; the target is a hydrophobic compound; the hydrophobic compound is selected from one or more of triazole pesticides, organochlorine pesticides, organophosphorus pesticides, and perfluoroalkanoic acid compounds. The concentration range of the target in the aqueous sample is trace to micro level, which is suitable for environmental monitoring, food safety testing, drug analysis and other fields.

[0018] In a preferred embodiment of the present invention, in step (2), the extraction time is 1 to 3 hours, and the extraction is carried out under stirring or shaking conditions. The stirring or shaking treatment can improve the extraction efficiency.

[0019] In a preferred embodiment of the present invention, in step (3), the desorption treatment is to immerse the extracted fiber head in a desorption solvent for desorption treatment; the desorption solvent is one or more of acetonitrile, ethanol, and acetone; the desorption treatment is carried out under ultrasound; and the desorption treatment time is 1 to 10 minutes.

[0020] In a preferred embodiment of the present invention, the instrument used for the instrumental analysis is one or more of an ultraviolet-visible spectrophotometer, a high performance liquid chromatograph, a gas chromatograph, a liquid chromatography-mass spectrometer, and a gas chromatography-mass spectrometer.

[0021] In a preferred embodiment of the present invention, when the target is a triazole pesticide, the material of the fiber head is polypropylene fiber, the extraction solvent is a deep eutectic solvent, and the decomposition solvent is acetonitrile; the deep eutectic solvent is composed of methyl trioctyl ammonium bromide and capric acid; the molar ratio of methyl trioctyl ammonium bromide to capric acid is 1:(1.5-2.5); for every 200 mL of aqueous sample to be tested, the corresponding amounts of polypropylene fiber, deep eutectic solvent, and desorption solvent are (15-25) mg, (50-70) μL, and (400-600) μL, respectively.

[0022] In a further preferred embodiment of the present invention, when the target is a triazole pesticide, the fiber head is made of polypropylene fiber, the extraction solvent is a deep eutectic solvent, and the decomposition solvent is acetonitrile; the deep eutectic solvent is composed of methyl trioctyl ammonium bromide and capric acid; the molar ratio of methyl trioctyl ammonium bromide and capric acid is 1:2; for every 200mL of the aqueous sample to be tested, the corresponding amounts of polypropylene fiber, deep eutectic solvent, and desorption solvent are 20mg, 60μL, and 500μL, respectively. Under this experimental condition, the detection of five triazole compounds (paclobutrazol, cyproconazole, tebuconazole, diniconazole, metconazole) can be achieved simultaneously, and a high enrichment factor and detection sensitivity are shown.

[0023] The technical solution of the present invention has the following advantages and beneficial effects:

[0024] The convenient and ready-to-use solvent extraction rod provided by the present invention includes: a hollow rod and a fiber head; the hollow rod is provided with an open end and a closed end, and the hollow rod is filled with an extraction solvent; the fiber head is fixed at the open end of the hollow rod; the hollow rod is provided with a breaking line on the tube wall near the closed end; the extraction solvent is a deep eutectic solvent or an ionic liquid; the material of the fiber head is a lipophilic fiber material. The above-mentioned convenient and ready-to-use solvent extraction rod of the present invention, when detecting hydrophobic target substances in aqueous samples, only needs to adsorb the extraction solvent in the fiber head, and can be directly used for the extraction of large-volume aqueous samples and the enrichment of target substances, greatly improving the detection efficiency, avoiding complex extraction, separation and other operations in the pretreatment, and also reducing the use of extraction solvents. Moreover, the device has a simple structure, is convenient for batch production and transportation, and is beneficial to reducing the detection cost.

[0025] The method for detecting target substances in aqueous samples using the above-mentioned convenient and ready-to-use solvent extraction rod provided by the present invention is based on liquid-phase microextraction with a fiber head and an extraction solvent, and can quickly extract and detect target substances in large-volume aqueous samples, achieving a lower detection limit and a higher enrichment efficiency, effectively improving the detection efficiency of target substances in large-volume aqueous samples, and meeting the requirements of rapid monitoring. Moreover, compared with traditional detection methods, this method has the advantages of simplicity, rapid extraction, low cost and environmental protection, and is suitable for the pretreatment of large-volume aqueous samples. Description of the Drawings

[0026] Figure 1 It is a schematic structural diagram of the convenient and ready-to-use solvent extraction rod of the present invention;

[0027] Figure 2 It is the scanning electron microscope (SEM) characterization result of the fiber diameters of four different polypropylene fiber samples in Test Example 1 of the present invention;

[0028] Figure 3 It is a visual experimental flow chart of the extraction when Oil Red O is added to the sample solution as a model analyte in Test Example 2 of the present invention;

[0029] Figure 4 It is the LC-UV chromatogram of the triazole pesticide standard solution (curve a), the aqueous solution of triazole pesticides after DES extraction treatment (curve b) and the aqueous solution of triazole pesticides without DES extraction treatment (curve c) in Test Example 2 of the present invention;

[0030] Figure 5 It is the optimization result of the molar ratio (A) and volume (B) of DES in Test Example 3 of the present invention;

[0031] Figure 6Optimization results of the volume of the aqueous solution of the sample to be tested in Test Example 3 of the present invention;

[0032] Figure 7 Optimization results of the DES extraction time in Test Example 3 of the present invention;

[0033] Figure 8 Optimization results of the type (A) of the desorption solvent, the volume (B) of the desorption solvent, and the desorption time (C) in Test Example 3 of the present invention;

[0034] Figure 9 Optimization results of the type of polypropylene fiber in Test Example 3 of the present invention;

[0035] Figure 1 In the figure, the meanings of the reference numerals are as follows: 1, hollow rod; 2, fiber head; 3, open end; 4, closed end; 5, extraction solvent; 6, broken line. Detailed implementation manners

[0036] In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be further described in detail below in conjunction with the specific implementation manners. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below. On the premise of no conflict, the following technical features of the embodiments of the present invention can also be combined with each other.

[0037] In the following embodiments and test examples of the present invention, taking the detection of triazole pesticides in aqueous samples as an example, the use effect of the convenient and ready-to-use solvent extraction rod of the present invention is described. Specifically, in the following embodiments and test examples, the target substances are five triazole pesticides (TPs), namely paclobutrazol, cyproconazole, tebuconazole, diniconazole, and metconazole. In other embodiments, the target substances can also be selected from other types, such as organochlorine pesticides, organophosphorus pesticides, perfluoroalkyl acids, etc.

[0038] In the embodiment of the present invention, paclobutrazol (PBZ, purity ≥ 95%), cyproconazole (CPZ, purity ≥ 95%), tebuconazole (TBZ, purity ≥ 98%), diniconazole (DNZ, purity ≥ 95%), trioctylmethylammonium chloride (MTOAB, purity ≥ 98%), and decanoic acid (DA, purity ≥ 99%) were purchased from Shanghai Titan Technology Co., Ltd. Methiconazole (MEZ, purity ≥ 96%) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. The stock solutions of the five TPs (TBZ, PBZ, CPZ, DNZ, and MEZ) were dissolved in acetonitrile at a concentration of 10 mg / mL; the TPs working solution was obtained by diluting the stock solution to the required concentration and diluting it with acetonitrile.

[0039] In the following embodiments and test examples of the present invention, four different polypropylene fibers are involved, which are from Huizhou Kangzhimei (recorded as brand 1), Fuzhou Bi'an Home Furnishing (recorded as brand 2), Zhejiang Youqin (recorded as brand 3) and Beijing Zhongzhou Lily (recorded as brand 4). All polypropylene fibers are used directly after purchase without treatment. Other raw materials, unless otherwise specified, are materials commonly used in the field and can be obtained through commercial channels.

[0040] Example 1

[0041] This embodiment provides a convenient and ready-to-use solvent extraction stick, the structural schematic diagram of which is shown in FIG. Figure 1 As shown: it includes a hollow rod 1 and a fiber head 2; the hollow rod 1 is provided with an open end 3 and a closed end 4, and the hollow rod 1 is filled with an extraction solvent 5; the fiber head 2 is fixed to the open end 3 of the hollow rod 1; the hollow rod 1 is provided with a break line 6 on the tube wall near the closed end 4; wherein the extraction solvent 5 is specifically a deep eutectic solvent; the fiber head 2 is made of a lipophilic fiber material, and the lipophilic fiber material is specifically polypropylene fiber. The material of the hollow rod 1 is plastic. When the convenient and ready-to-use solvent extraction rod is not in use, the closed end of the hollow rod is placed downward to prevent the extraction solvent from flowing out.

[0042] When using the convenient and ready-to-use solvent extraction stick to detect targets in aqueous samples, directly place the closed end of the hollow stick in the convenient and ready-to-use solvent extraction stick upwards, then break the hollow stick along the breaking line, and the extraction solvent filled in the hollow stick is adsorbed on the fiber head by gravity, and then the fiber head adsorbed with the extraction solvent is immersed in the aqueous sample to be tested to extract the aqueous sample to be tested and enrich the target. Experiments have confirmed that after the convenient and ready-to-use solvent extraction stick is used for the detection of targets in aqueous samples, it can quickly and efficiently enrich the hydrophobic targets in the aqueous samples, has the advantages of simple operation and low cost, and is suitable for the detection of trace targets in aqueous samples. In addition, since the convenient and ready-to-use solvent extraction stick is easy to prepare and low in cost, in order to avoid sample contamination, the convenient and ready-to-use solvent extraction stick usually needs to be used once to avoid reuse.

[0043] In other embodiments, based on the above-mentioned convenient and ready-to-use solvent extraction rod, a fiber head can also be fixed to the closed end of the hollow rod to prevent the extraction solvent from splashing out when it is broken.

[0044] In other embodiments, the hollow rod can also be made of glass or other suitable materials, and the diameter of the hollow rod can be set according to the amount of the extraction solvent, generally 0.2 to 3 mm. The lipophilic fiber material can also be polyester fiber or other lipophilic materials. The extraction solvent can also be an ionic liquid or other high-boiling hydrophobic solvent.

[0045] Example 2

[0046] This embodiment provides a method for detecting a target in an aqueous sample using the convenient, ready-to-use solvent extraction stick of Embodiment 1. Specifically, this embodiment uses an aqueous solution containing triazole pesticides as the aqueous sample to be tested and triazole pesticides as the target to illustrate the detection method of the present invention. In other embodiments, the aqueous sample may also be other samples with water as the matrix, and the target may also be other compounds to be tested.

[0047] The method for detecting a target in an aqueous sample using the above-mentioned convenient and ready-to-use solvent extraction stick comprises the following steps:

[0048] (1) Preparation of a convenient and ready-to-use solvent extraction rod: Take a hollow rod with an open end and a closed end, set a break line on the tube wall of the closed end, then place the open end upward, inject the extraction solvent into the hollow rod along the open end, and further wrap the fiber head at the open end to obtain a convenient and ready-to-use solvent extraction rod. Among them, the fiber head is polypropylene fiber (20 mg), and the extraction solvent is a deep eutectic solvent (60 μL). The deep eutectic solvent is composed of methyl trioctyl ammonium bromide and capric acid in a molar ratio of 1:2. When preparing the deep eutectic solvent, methyl trioctyl ammonium bromide and capric acid are mixed in a molar ratio of 1:2, and stirred in a 60°C water bath until a uniform, clear and transparent oily liquid is obtained, that is, a deep eutectic solvent.

[0049] (2) Place the closed end of the hollow rod in the convenient ready-to-use solvent extraction rod upward, then break the hollow rod along the break line. The extraction solvent filled in the hollow rod is adsorbed on the fiber head by gravity. Immerse the fiber head adsorbed with the deep eutectic solvent in a beaker containing 200 mL of the aqueous sample to be tested. Use a cardboard partition to stabilize the device to ensure that the fiber head is immersed to about one-third of the liquid surface and is located in the center of the solution. Add a rotor to the beaker, start the stirring device at the bottom of the beaker, and stir the extraction for 120 minutes to enhance the transfer of the target.

[0050] (3) After the extraction is completed, add 500 μL of desorption solvent (ACN) to the centrifuge tube, take out the polypropylene fiber and immerse it in the desorption solvent to ensure sufficient contact. Use ultrasonic treatment for 2 min to promote desorption. Finally, collect the desorbed solution, take 20 μL and analyze it by high performance liquid chromatography-ultraviolet detection method to obtain the content of triazole compounds in the aqueous sample to be tested.

[0051] Experimental Example 1. Characterization of Polypropylene Fibers

[0052] The fiber diameters of four different brands of polypropylene fibers (Brands 1-4) were characterized by scanning electron microscopy (SEM), and the results are as Figure 2 shown. Among them, Figure 2 A, B, C, and D in are the SEM images of Brands 1, 2, 3, and 4 of polypropylene fibers in sequence. Different lowercase letters (a)-(c), (d)-(f), (g)-(i), (j)-(l) are the SEM characterization results of Brands 1, 2, 3, and 4 of polypropylene fibers at different magnification factors respectively.

[0053] Figure 2 The results show that the fiber diameters of Brands 1-4 of polypropylene fibers range from 18 to 27 μm. This relatively small fiber diameter significantly enhances the specific surface area of the polypropylene fiber, thus providing optimal conditions for the mass transfer of effective adsorption of DES and target analytes. SEM morphological analysis further reveals that the fiber structure of the polypropylene fiber presents a highly ordered and densely distributed network, and the fiber arrangement is uniform and smooth. Further, through methylene blue staining and oil red O staining tests, the present invention also confirms that the polypropylene fiber has excellent hydrophobicity and lipophilicity.

[0054] Experimental Example 2. Preliminary Verification of the Extraction Performance of Deep Eutectic Solvents

[0055] Triazole compounds (TPs) have high hydrophobicity (the Log P values of paclobutrazol, cyproconazole, tebuconazole, diniconazole, and metconazole are between 3.18 and 4.28, all exceeding 3) and low solubility in water. Therefore, a suitable extractant needs to be selected. Through preliminary screening, the present invention selects methyltrioctylammonium chloride (MTOAB) and decanoic acid (DA) with appropriate viscosity and hydrophobicity, prepares a deep eutectic solvent (DES) by mixing them in a specific molar ratio, and uses it in the extraction test of triazole pesticides to explore its feasibility in extracting triazole pesticides.

[0056] In this test, the present invention adds oil red O as a model analyte to water to show the extraction process and conducts a visualization experiment of oil red O. The operation process is as Figure 3 shown. Figure 3Among them, (A) is a picture of adding Oil Red O to the sample solution and the polypropylene fiber before extracting the sample solution; (B) is a picture of adding the deep eutectic solvent (DES) of Example 2 to the polypropylene fiber; (C) is a picture of putting the polypropylene fiber added with DES into the sample solution and stirring for extraction for 80 minutes; (D) is a picture of taking out the polypropylene fiber after the extraction ends; (E) is a picture of transferring the polypropylene fiber to 500 μL of acetonitrile (ACN) for desorption; (F) is a picture of taking out the polypropylene fiber after ACN desorption to obtain a desorbed solution containing the analyte. Through Figure 3 The visualization experiment of Oil Red O in

[0057] further verified that DES can effectively adsorb Oil Red O, supporting its potential as an extractant for triazole pesticides. In further experiments, an aqueous solution containing PBZ, CPZ, TBZ, DNZ, MEZ and a total concentration of 200 ng / mL of triazole compounds was prepared according to the present invention. The detection method of Example 2 was adopted, and the deep eutectic solvent (DES) was used for extraction. The extracted and desorbed samples were analyzed by high performance liquid chromatography-ultraviolet detection (LC-UV), and compared with the aqueous solution of triazole pesticides (total concentration of 200 ng / mL) without extraction treatment in this experiment and the standard solution of triazole pesticides (10 μg / mL). Among them, LC-UV analysis was performed using an Agilent 1200 HPLC system, which included a quaternary pump (G1311A), an autosampler (G1313A), a column thermostat (G1316A), a degassing unit (G1322A), a diode array detector (DAD, G1315B) and a fluorescence detector (FLD, G1321A). Data processing was carried out by Agilent Chem Station or Open Lab CDS software. The separation of the five TPs was carried out using an Agilent ZORBAX SB-C18 column (4.6×250 mm, 5 μm), the mobile phase was solvent A (ultrapure water) and solvent B (ACN), the volume ratio was 40:60, the elution time was 20 min, the column temperature was 30 °C, the flow rate was 1.0 mL / min, the detection wavelength was 225 nm, and the injection volume was 10 μL. The LC-UV chromatograms of the three solutions are as Figure 4 shown.

[0058] It can be seen from Figure 4 that the chromatogram (curve b) after extraction with the deep eutectic solvent successfully detected the five TPs, and the chromatographic peaks were consistent with the reference chromatogram (curve a). In the sample without extraction with the deep eutectic solvent (curve c), the pesticide peak signal was significantly weakened, indicating that the deep eutectic solvent plays a key role in extraction, while the extraction ability of the polypropylene fiber is limited. This part of the experiment provides a preliminary verification for the extraction of triazole pesticides in aqueous samples by the polypropylene fiber and deep eutectic solvent of the present invention, laying a foundation for subsequent optimization and performance research.

[0059] Experimental Example III: Optimization of Extraction Conditions

[0060] (1) Molar Ratio and Volume of DES

[0061] In the present invention, trioctylmethylammonium chloride (MTOAB) was used as the hydrogen bond acceptor (HBA), and decanoic acid (DA) was used as the hydrogen bond donor (HBD) to synthesize the deep eutectic solvent (DES). The specific operation was as follows: MTOAB and DA were mixed at a molar ratio of 1:2 and stirred in a water bath at 60 °C until a uniform, clear, and transparent oily liquid was obtained. The synthesized DES was stored at room temperature for experimental use. At the same time, DES with other molar ratios (2:1, 1:1, 1:3, 1:4) was prepared using the same method and stored at room temperature for experimental use.

[0062] The DES with different molar ratios synthesized above was used, and the extraction experiment of TPs was carried out using the convenient ready-to-use solvent extraction rod of Example 1. Under the same other conditions, the enrichment factors of TPs by DES with different molar ratios are as shown in Figure 5 Figure A therein.

[0063] The molar ratio of HBA to HBD significantly affects the physicochemical properties of DES, and thus affects the extraction efficiency of TPs. As can be seen from Figure 5 Figure A therein, when the molar ratio of MTOAB (HBA) to DA (HBD) is 1:2, the extraction efficiency is the best. Considering that a higher DA content results in a lower viscosity, an excessive amount of HBD will affect the interaction between HBA and TPs, leading to a decrease in the enrichment factor. Therefore, 1:2 was selected as the optimal molar ratio.

[0064] During the extraction process, the volume of the extractant is also crucial for the extraction efficiency. Using the above-synthesized DES (molar ratio of MTOAB to DA is 1:2), the volume of the DES extractant was changed (50, 60, 70, 80, 100 μL), and the extraction experiment of TPs was carried out. The enrichment factors of TPs with different DES volumes are as shown in Figure 5 Figure B therein.

[0065] As can be seen from Figure 5 Figure B therein, as the volume of DES increases, the enrichment factor first increases and then decreases, and the enrichment factor value is the largest at 60 μL. Too small a volume will result in insufficient extraction, and too large a volume will reduce the efficiency due to the dilution effect. Therefore, 60 μL was determined as the optimal volume.

[0066] (2) Volume of Sample Solution

[0067] During the single-drop liquid-phase microextraction process, the volume of the sample solution to be measured has an important impact on the extraction efficiency and enrichment factor. Using the DES synthesized with the above-mentioned optimal molar ratio and the convenient and ready-to-use solvent extraction rod of Example 1, while keeping other conditions the same, the volume of the sample solution to be measured (50, 100, 150, 200 mL) was changed to conduct the extraction experiment of TPs. Under different sample solution volume conditions, the enrichment factors of TPs are as shown in Figure 6 as follows.

[0068] Figure 6 In

[0069] , by comparing the experiments with different volumes of the sample solution to be measured, the results show that the enrichment factor gradually increases with the increase of the sample solution volume and reaches the peak value at 200 mL. Therefore, 200 mL is determined as the optimal volume. (3) Extraction time

[0070] Using the DES synthesized above and the convenient and ready-to-use solvent extraction rod of Example 1, while keeping other conditions the same, the extraction time (40, 80, 120, 160, 200, 240 min) was changed to conduct the extraction experiment of TPs. Under different extraction time conditions, the enrichment factors of TPs are as shown in Figure 7 as follows.

[0071] Figure 7 The optimization results of the extraction time in

[0072] show that the enrichment factor increases significantly within 40 to 120 min, and then the increase rate slows down. Therefore, 120 min is determined as the optimal extraction time to ensure efficient extraction and a large enrichment factor. (4) Types, volumes and desorption times of desorption solvents

[0073] The types, volumes and times of desorption solvents also have an impact on the desorption efficiency. Using the DES synthesized above and the convenient and ready-to-use solvent extraction rod of Example 1, while keeping other conditions the same, the types of desorption solvents (acetonitrile - ACN, methanol - MeOH, ethanol - EtOH, acetone - Acetone), volumes (0.5, 0.8, 1, 1.2 mL) and desorption times (1, 2, 3, 5, 8, 10 min) were changed to conduct the extraction experiment of TPs. Under different conditions of the types, volumes and desorption times of desorption solvents, the enrichment factors of TPs are respectively as shown in A - C in Figure 8 as follows.

[0074] It can be seen from Figure 8 that ACN performs the best as the desorption solvent (Figure A), a volume of 0.5 mL of ACN can obtain the highest enrichment factor (Figure B), and 2 min of ultrasonic treatment is sufficient to achieve effective desorption (Figure C).

[0075] (5) Selection of polypropylene fiber types

[0076] This experiment evaluated the effect of different brands of polypropylene fibers on the extraction efficiency at the fiber head. Using the synthesized DES above and the convenient and ready-to-use solvent extraction rod of Example 1, under the same other conditions, the type of polypropylene fiber (Brand 1, Brand 2, Brand 3, Brand 4) was changed to conduct the extraction experiment of TPs. The enrichment factors of TPs with different polypropylene fibers are as Figure 9 shown.

[0077] As Figure 9 can be seen, the polypropylene fiber produced by Brand 4 (Zhongzhou Lily brand) of polypropylene fiber showed the best performance, significantly improving the enrichment factor of the target analyte. Therefore, Brand 4 was selected as the best polypropylene fiber.

[0078] Test Example IV. Method verification

[0079] Under the optimal conditions optimized in Test Example III, the enrichment factors of the five TPs measured were 38 times for PBZ, 42 times for CPZ, 67 times for TBZ, 80 times for MEZ, and 96 times for DNZ.

[0080] To further verify the method and analyze actual samples, the present invention uses LC-MS to determine TPs for further verification. The analysis uses an Applied Biosystems Sciex 5500QTrap mass spectrometer, equipped with a Turbo V ion source, using the electrospray ionization (ESI) mode. The mass spectrometry operates in the multiple reaction monitoring (MRM) mode, with positive ion detection. The MRM parameters are optimized, including the cone voltage (CV) and collision energy (CE).

[0081] The mass spectrometry parameters are: source temperature 550 °C, spray voltage 5500 V, curtain gas pressure 30 psi, nitrogen flow rate 50 psi, turbo gas flow 50 psi. Data processing uses software. Chromatographic separation uses a Waters Acquity BEH C18 column (100 mm × 2.1 mm, 1.7 μm). The eluent is solvent A (0.1% formic acid aqueous solution) and solvent B (0.1% formic acid acetonitrile solution), with a volume ratio of 45:55, a flow rate of 0.2 mL / min, an injection volume of 2 μL, a total analysis time of 10 min, and the sample bottle temperature is maintained at 4 °C.

[0082] After LC-MS verification, the linear ranges, regression data, and the measured results of LOD and LOQ of each TPs are shown in Table 1. The intra-day, intra-day relative recovery rates, and RSD results at three peak levels of the 5 TPs are shown in Table 2.

[0083] Table 1. Determination of linear range, regression data, LOD, and LOQ

[0084]

[0085] Table 2. Intra-day and inter-day relative recovery rates and RSDs at three peak levels for the determination of five TPs

[0086]

[0087]

[0088] As can be seen from Table 1, through LC-MS coupling verification, TPs showed a good linear relationship in the concentration range of 10 - 100 ng / mL. The LODs were 2.98 ng / mL for PBZ, 2.83 ng / mL for CPZ, 3.67 ng / mL for TBZ, 2.65 ng / mL for MEZ, and 2.60 ng / mL for DNZ, respectively. As can be seen from Table 2, both the precision (RSD < 10%) and the relative recovery rate (91.3% - 102.7%) met the requirements, indicating the high precision and reliability of this method.

[0089] Based on the above experimental results, for the detection of triazole compounds in aqueous samples, the optimized extraction conditions of the present invention include: 20 mg polypropylene fiber (from brand 4), DES composed of MTOAB and DA with a molar ratio of 1:2, 60 μL extractant, 200 mL sample solution, 120 min extraction, 2 min ultrasonic desorption, and 500 μL desorption solvent. Under the optimized conditions, the EF range of the five TPs was 38 to 96, showing a high enrichment factor and detection sensitivity. In the concentration range of 10 to 100 ng / mL, the correlation coefficients (R2) of the linear calibration curves of the five triazole pesticides all exceeded 0.995, indicating that this method has a good linear range and high precision. The limit of quantification (LOQ) was 8.85 - 9.93 ng / mL, meeting the requirements for the detection of triazole pesticide residues. The precision (RSD < 10.0%) and accuracy (relative recovery rate: 91.3% - 102.7%) of the method were both within the acceptable range, verifying the reliability and stability of the method.

[0090] In summary, the convenient and ready-to-use solvent extraction rod provided by the present invention can be directly used for the extraction of large-volume aqueous samples and the enrichment of hydrophobic targets, effectively improving the detection efficiency, avoiding complex extraction, separation and other operations in the pretreatment, and also reducing the use of extraction solvents. Moreover, the device has a simple structure, is convenient for mass production and transportation, and is conducive to reducing the detection cost.

[0091] Furthermore, the method for detecting target substances in aqueous samples using a convenient and ready-to-use solvent extraction rod provided by the present invention has the following comprehensive characteristics: (i) The DES is composed of methyltrioctylammonium bromide (MTOAB) and decanoic acid (DA), has good hydrophobicity and low volatility, can effectively extract hydrophobic target substances in aqueous samples, and is harmless to the environment, making it an ideal choice for green analytical methods. (ii) The combination of polypropylene fiber and deep eutectic solvent can effectively improve the extraction efficiency and shorten the desorption time. Experimental results show that desorption can be achieved within only <5 min after extraction by the present invention, thus significantly shortening the time of the traditional desorption step. (iii) The combination of polypropylene fiber and deep eutectic solvent can effectively improve the detection sensitivity, achieving a low detection limit (LOD) and a high enrichment factor (EF), which is beneficial to improving the detection efficiency of target substances in large-volume aqueous samples. (iv) Detection is carried out using liquid chromatography in combination with an ultraviolet detector, without the need to configure expensive detection instruments such as mass spectrometers, simplifying the operation process and improving the detection efficiency.

[0092] Therefore, the detection method provided by the present invention, based on an efficient and simple extraction technique, can quickly extract and effectively enrich trace target substances in large-volume aqueous samples, achieve a low detection limit and a high enrichment efficiency, has excellent accuracy and precision, can also effectively improve the detection efficiency of large-volume aqueous samples, and meet the requirements of rapid monitoring. Moreover, compared with traditional detection methods, especially in the analysis of traditional Chinese medicine liquids, food and beverages, and sewage, this method has the advantages of simplicity, rapid extraction, low cost, and environmental protection, is suitable for the treatment of large-volume aqueous samples, can not only provide a new strategy for the detection of trace target substances in large-volume aqueous samples, but also provide a new technical direction and technical support for the improvement of analytical detection means, and has broad application potential in actual environmental monitoring.

[0093] Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A convenient, ready-to-use solvent extraction stick, characterized in that: include: A hollow rod and a fiber head; the hollow rod is provided with an open end and a closed end, and the hollow rod is filled with an extraction solvent; the fiber head is fixed at the open end of the hollow rod; a break line is provided on the tube wall of the hollow rod near the closed end; the extraction solvent is a deep eutectic solvent or an ionic liquid; the fiber head is made of a lipophilic fiber material.

2. The convenient, ready-to-use solvent extraction stick according to claim 1, characterized in that: The lipophilic fiber material is polypropylene fiber or polyester fiber.

3. A use of the convenient, ready-to-use solvent extraction stick as claimed in claim 1, characterized in that: The application is the use of a convenient, ready-to-use solvent extraction stick in the detection of a target in an aqueous sample.

4. A method for detecting a target in an aqueous sample using the convenient, ready-to-use solvent extraction stick as claimed in claim 1, characterized in that: The following steps are involved: (1) preparing a convenient and ready-to-use solvent extraction rod, placing the closed end of the hollow rod in the convenient and ready-to-use solvent extraction rod upward, and then breaking the hollow rod along the breaking line, so that the extraction solvent filled in the hollow rod is adsorbed on the fiber head by gravity; (2) completely immersing the fiber head adsorbed with the extraction solvent into the aqueous sample to be tested for extraction; (3) Desorbing the extracted fiber head with a desorption solvent, collecting the desorption liquid, and performing instrumental analysis to obtain the content of the target substance in the aqueous sample to be tested.

5. The method for detecting a target in an aqueous sample using a convenient, ready-to-use solvent extraction stick according to claim 4, characterized in that: In step (2), the aqueous sample to be tested is selected from one or more of traditional Chinese medicine liquid, food and beverage, and sewage; the target substance is a hydrophobic compound; the hydrophobic compound is selected from one or more of triazole pesticides, organochlorine pesticides, organophosphorus pesticides, and perfluoroalkanoic acid compounds.

6. The method for detecting a target in an aqueous sample using a convenient, ready-to-use solvent extraction stick according to claim 4, characterized in that: In step (2), the extraction time is 1 to 3 hours; the extraction is carried out under stirring or shaking conditions.

7. The method for detecting a target in an aqueous sample using a convenient, ready-to-use solvent extraction stick according to claim 4, characterized in that: In step (3), the desorption treatment is to immerse the extracted fiber head in a desorption solvent for desorption treatment; the desorption solvent is one or more of acetonitrile, ethanol, and acetone; the desorption treatment is carried out under ultrasound; and the desorption treatment time is 1 to 10 minutes.

8. The method for detecting a target in an aqueous sample using a convenient, ready-to-use solvent extraction stick according to claim 4, characterized in that: The instrument used for the instrumental analysis is one or more of an ultraviolet visible spectrophotometer, a high performance liquid chromatograph, a gas chromatograph, a liquid chromatography-mass spectrometer, and a gas chromatography-mass spectrometer.

9. The method for detecting a target in an aqueous sample using a convenient and ready-to-use solvent extraction stick according to claim 4, characterized in that: When the target is a triazole pesticide, the material of the fiber head is polypropylene fiber, the extraction solvent is a deep eutectic solvent, and the decomposition solvent is acetonitrile; the deep eutectic solvent is composed of methyl trioctyl ammonium bromide and capric acid; the molar ratio of methyl trioctyl ammonium bromide to capric acid is 1:(1.5-2.5); for every 200 mL of the aqueous sample to be tested, the corresponding amounts of polypropylene fiber, deep eutectic solvent, and desorption solvent are (15-25) mg, (50-70) μL, and (400-600) μL, respectively.

10. The method for detecting a target in an aqueous sample using a convenient and ready-to-use solvent extraction stick according to claim 9, characterized in that: When the target is a triazole pesticide, the material of the fiber head is polypropylene fiber, the extraction solvent is a deep eutectic solvent, and the decomposition solvent is acetonitrile; the deep eutectic solvent is composed of methyl trioctyl ammonium bromide and capric acid; the molar ratio of methyl trioctyl ammonium bromide to capric acid is 1:2; for every 200 mL of aqueous sample to be tested, the corresponding amounts of polypropylene fiber, deep eutectic solvent, and desorption solvent are 20 mg, 60 μL, and 500 μL, respectively.

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