Solid-phase extraction system and method suitable for screening unknown pollutants of environmental water sample

Abstract

The invention provides a solid-phase extraction system suitable for screening unknown pollutants in an environmental water sample, which comprises three sample bottles arranged on an oscillator (6), a sample injection interface kit (9), a sample injection needle kit (10), a multi-way valve I (11), a multi-way valve II (19), an injection pump (20), a sample loading needle kit (22) and three solid-phase extraction columns, the neutral extract receiving pipe (32), the acid extract receiving pipe (33), the alkaline extract receiving pipe (34) and the flow guide frame (31) are arranged on the receiving pipe frame (35) and are respectively used for receiving extracts of a solid-phase extraction column, the guide rail (36) is used for moving the flow guide frame (31) and the receiving pipe frame (35), and the flow guide pipe I (27), the flow guide pipe II (28), the water sample flow guide groove (29) and the organic solvent flow guide groove (30) are arranged on the flow guide frame (31). The invention also provides a solid-phase extraction method applicable to screening of unknown pollutants in an environmental water sample, which is realized by adopting the system.

Description

Technical Field

[0001] The present invention relates to the technical fields of detection and analysis of organic matters in water and solid-phase extraction, and particularly to an extraction system and method suitable for extracting organic pollutants in water by using a solid-phase extraction method, and is particularly suitable for screening unknown pollutants in environmental water samples. Background Art

[0002] With the continuous in-depth research of environmental studies, new pollutants have gradually attracted great attention from domestic and foreign research scholars and the public due to their high detection rate and high toxicity, which pose potential threats to the ecological environment or human health. Since there are many types of new pollutants in water and they can be transformed into products with stronger toxicity, traditional extraction methods can no longer meet the monitoring requirements for the discovery, identification, and comprehensive risk assessment of new pollutants. Using solid-phase extraction technology to comprehensively extract and effectively identify known and unknown pollutants in water can greatly increase the throughput of new pollutant monitoring in water, meet the needs of simultaneous monitoring of known and unknown new pollutants, and clarify the occurrence status and pollution characteristics of new pollutants in water.

[0003] In view of the significant differences in the properties of different types of organic pollutants, their existence forms in water are also different. Some exist in molecular state, while some exist in ionic state. Therefore, when synchronously detecting multiple target substances or screening and identifying unknown pollutants, the pH value of the extraction solution has a significant impact on the extraction results. In addition, different types of solid-phase extraction columns show different extraction efficiencies and selectivities for various pollutants. Therefore, reasonably adjusting the pH value of the extraction solution and selecting a suitable solid-phase extraction column are key steps to ensure the accuracy of the analysis results and improve the detection sensitivity. Matching a suitable solid-phase extraction column at the optimal pH value of the sample can improve the extraction efficiency of different types of compounds and ensure the sensitivity, accuracy, and reliability of the analysis results. Neutral pH conditions are suitable for conventional pollutants such as polycyclic aromatic hydrocarbons, organochlorine pesticides, phthalic acid esters, chlorinated hydrocarbons, etc., and are also suitable for new pollutants such as organophosphates, perfluorinated compounds, and some antibiotics. Pollutants suitable for acidic pH conditions are such as phenols with low acid dissociation constants (pKa) and some antibiotics. Pollutants suitable for basic pH conditions are such as anilines and pyridines. This requires the sample to be extracted under neutral, acidic, and basic conditions simultaneously.

[0004] At present, the methods for analyzing pollutants in water using solid phase extraction involve limited types of target substances, and all of them are aimed at a single type of compound, such as "Determination of 17 heterocyclic pesticides in water quality by high performance liquid chromatography" (HJ 1395-2024HLB column, pH4-8), "Determination of 18 sulfonamide antibiotics and trimethoprim in water quality by high performance liquid chromatography-triple quadrupole mass spectrometry" (HJ 1398-2024HLB column, pH4-7), "Determination of 17 fluoroquinolone antibiotics in water quality by high performance liquid chromatography-triple quadrupole mass spectrometry" (HJ 1399-2024HLB column, pH 2-3), "Determination of 9 alkylphenol compounds and bisphenol A in water quality by solid phase extraction / high performance liquid chromatography" (HJ 1192-2021HLB column, pH1-2), "Water Quality - Determination of Perfluorooctane Sulfonic Acid and Perfluorooctanoic Acid and Their Salts - Isotope Dilution / Liquid Chromatography-Triple Quadrupole Mass Spectrometry" (HJ 1333-2023 Weak Anion Exchange SPE Column, pH6-8), "Water Quality - Determination of 17 Aniline Compounds - Liquid Chromatography-Triple Quadrupole Mass Spectrometry" (HJ 1048-2019 Cation Exchange SPE Column, pH7-8), etc. There are many types of pollutants in water, their properties vary greatly, and their occurrence states are unclear. At present, there is a lack of broad-spectrum, high-throughput extraction and enrichment methods for screening pollutants in water. The solid phase extraction method has significant advantages in screening organic matter in water because of its large enrichment ratio, less solvent usage, and convenient automatic enrichment of multiple samples.

[0005] Since the screening method requires as many types of unknown compounds in the enriched sample as possible, it is difficult to achieve the requirement with a single enrichment of the water sample. Therefore, it is necessary to consider the influencing factors when enriching different types of compounds, such as the influence of pH value and the type of solid phase extraction column suitable for the target compound. The same water sample should be extracted and enriched multiple times, and the extraction eluents should be combined for concentration, volume determination and subsequent instrumental analysis.

[0006] However, the existing solid phase extraction devices can only extract and enrich the same sample once. If other target substances are measured under different pH values ​​in the sample, or different types of extraction columns are used, the only option is to re-sample and extract and enrich. Since there may be a risk of cross-extraction of extracted compounds in the two enrichment processes, which will cause significant deviations in the quantitative analysis results, the eluents obtained from the two extractions should not be mixed during analysis, but should be concentrated, fixed to volume and analyzed by instruments separately. This process has doubled the workload of sample analysis. Summary of the invention

[0007] To solve the above problems, the present invention provides a solid-phase extraction system and method that can conveniently achieve multiple solid-phase extractions of the same sample after one-time sampling, that is, the sample taken in one measurement is extracted under neutral, acidic and alkaline conditions or for organic neutral molecules, cations and anions, respectively, which is convenient for subsequent concentration and injection after combining the extraction liquids, and the instrument detection and analysis is completed at one time, improving the accuracy of sample analysis. The technical solution of the present invention is as follows:

[0008] A solid-phase extraction system suitable for screening unknown pollutants in environmental water samples, including three sample bottles, namely a neutral sample bottle 1, an acidic sample bottle 2 and a basic sample bottle 3 placed on an oscillator 6, an injection interface kit 9, an injection needle kit 10, a multi-way valve I 11, a multi-way valve II 19, an injection pump 20, a loading needle kit 22, three solid-phase extraction columns, namely a neutral extraction column 24, an acidic extraction column 25 and a basic extraction column 26, a neutral extract receiving tube 32, an acidic extract receiving tube 33 and a basic extract receiving tube 34 placed on a receiving tube rack 35 for respectively receiving the extracts of the solid-phase extraction columns, a diversion rack 31, a guide rail 36 for moving the diversion rack 31 and the receiving tube rack 35, a diversion tube I 27, a diversion tube II 28, a water sample diversion groove 29 and an organic solvent diversion groove 30 placed on the diversion rack 31; wherein,

[0009] The injection pipeline 8 of each sample bottle can be selectively connected to the injection needle kit 10 through the injection interface kit 9;

[0010] The multi-way valve I 11 is a solvent selection valve, which is provided with a plurality of solvent inflow interfaces and a solvent outflow port 18, and the solvent outflow port 18 is communicated with the selected solvent inflow interface according to needs;

[0011] The multi-way valve II 19 includes a plurality of single-channel interfaces and a selection interface, and the selection interface is communicated with a selected single-channel interface according to needs; the solvent outflow port 18 of the multi-way valve I 11 is communicated with the first single-channel interface of the multi-way valve II 19; the second single-channel interface of the multi-way valve II 19 is communicated with the injection needle kit 10, the third single-channel interface of the multi-way valve II 19 is communicated with the loading needle kit 22, and the injection pump 20 selectively extracts a certain amount of water sample from the sample bottle through the selection interface, the second single-channel interface, the injection needle kit 10 and the injection interface kit 9. After the selected water sample is selected between the selection interface and the third single-channel interface of the multi-way valve II 19, it is injected into the corresponding solid-phase extraction column through the loading needle kit 22. The diversion tube I 27 and the diversion tube II 28 are respectively used to introduce the water samples flowing out after loading the neutral extraction column 24 and the acidic extraction column 25 into the corresponding sample bottles; the water sample diversion groove 29 is used to introduce the water sample flowing out after loading the basic extraction column 26 into the waste water tank 38 through the infusion tube, and the organic solvent diversion groove 30 is used to introduce the organic solvent flowing out after activating the solid-phase extraction column into the organic waste liquid tank 37.

[0012] Furthermore, a counterweight 5 with an outer layer coated with polytetrafluoroethylene is provided at the end of the sample injection pipeline 8 of each sample bottle.

[0013] Furthermore, it also includes a gas source 42, a gas pipeline 39, a solenoid valve 40 and a pressure reducing valve 41. The gas source 42 is connected to the fourth single-channel interface of the multi-way valve 19 through the pressure reducing valve 41, the solenoid valve 40 and the gas pipeline 39 in sequence.

[0014] Furthermore, it also includes a sample pH value adjusting device for measuring and adjusting the pH value of the sample in the sample bottle.

[0015] The present invention also provides a solid phase extraction method for screening unknown pollutants in environmental water samples using the solid phase extraction system. First, the order of sample extraction is determined, and the samples are extracted in the predetermined order. The following steps 1 to 18 are to extract the samples in the order of neutral, acidic, and alkaline. If it is necessary to extract the samples in other orders, the corresponding step order should be adjusted:

[0016] The first step is to prepare neutral samples: place the neutral, acidic and alkaline sample bottles on the oscillator 6 in sequence, take a certain volume of water sample and put it into the neutral sample bottle 1, and place the sampling line 8 with a counterweight 5 at the bottom into the neutral sample bottle 1.

[0017] The second step is to activate the neutral extraction column 24: use the injection pump 20 to extract the liquid required for activating the solid phase extraction column in turn through the multi-way valve 2 19 and the multi-way valve 1 11, and the outflowing liquid is introduced into the organic waste liquid tank 37 or the wastewater tank 38.

[0018] The third step is to load the neutral extraction column 24: use the injection pump 20 to extract the water sample in the neutral sample bottle 1 through the multi-way valve 2 19 and the injection needle kit 10, and inject it into the neutral extraction column 24 through the loading needle sleeve 22, and move the guide frame 31 by moving the guide rail 36 to make the guide tube 1 27 align with the neutral extraction column 24 above, so that the water sample flowing out after the neutral extraction flows into the acid sample bottle 2 through the guide tube 1 27.

[0019] The fourth step is eluting the neutral extraction column 24: the liquid for eluting the neutral extraction column 24 is extracted by the injection pump 20 through the multi-way valve 2 19 and the multi-way valve 1 11 to elute the neutral extraction column 24.

[0020] Step 5, drying the neutral extraction column 24: use the pressure reducing valve 41 to adjust the pressure of the drying gas flowing out of the gas source 42, open the solenoid valve 1 40, connect the multi-way valve 2 19 to the injection needle in the sample needle kit 22, and dry the neutral extraction column 24 with the flowing gas.

[0021] Step 6, elution of neutral extraction column 24: Use syringe pump 20 to extract a certain volume of liquid for eluting neutral extraction column 24 through multi-way valve II 19 and multi-way valve I 11, and pass it through neutral extraction column 24 at a certain flow rate. Move receiving tube rack 35 through guide rail 36 to collect the effluent in neutral extract receiving tube 32.

[0022] Step 7, adjust the pH value of the water sample flowing out of acidic sample bottle 2 after neutral extraction until the required pH value is reached.

[0023] Step 8, activation of acidic extraction column 25: Connect acidic extraction column 25 to sample injection needle kit 22. Select the activation solvent as needed and activate acidic extraction column 25 in the same way as in Step 2.

[0024] Step 9, sample loading on acidic extraction column 25: Move injection interface kit 9 to connect the injection needle in sample injection needle kit 10 to acidic sample bottle 2. Load the sample on acidic extraction column 25 in the same way as in Step 3, and make the water sample flowing out after acidic extraction flow into alkaline sample bottle 3 through diversion tube II 28.

[0025] Step 10, rinsing of acidic extraction column 25: Use syringe pump 20 to extract the solvent or solution for rinsing acidic extraction column 25 through multi-way valve II 19 and multi-way valve I 11 to rinse acidic extraction column 25.

[0026] Step 11, drying of acidic extraction column 25: Dry acidic extraction column 25 in the same way as in Step 5.

[0027] Step 12, elution of acidic extraction column 25: Use syringe pump 20 to extract a certain volume of liquid for eluting acidic extraction column 25 through multi-way valve II 19 and multi-way valve I 11, and pass it through acidic extraction column 25 at a certain flow rate. Move receiving tube rack 35 through guide rail 36 to collect the effluent in acidic extract receiving tube 33.

[0028] Step 13, adjust the pH value of the water sample flowing out of alkaline sample bottle 3 after acidic extraction until the required alkaline pH value is reached.

[0029] Step 14, activation of alkaline extraction column 26: Connect alkaline extraction column 26 to sample injection needle kit 22. Select the activation solvent as needed and activate alkaline extraction column 26 in the same way as in Step 2.

[0030] Step 15, sample loading on alkaline extraction column 26: Move sample injection interface kit 9 to connect the injection needle in sample injection needle kit 10 to alkaline sample bottle 3 and load the sample on alkaline extraction column 26.

[0031] Step 16, rinsing of alkaline extraction column 26.

[0032] Step 17, drying of alkaline extraction column 26.

[0033] Step 18, elution of the basic extraction column 26: Use the syringe pump 20 to extract a certain volume of liquid for eluting the basic extraction column 26 through the multi-way valve II 19 and the multi-way valve I 11, and pass it through the basic extraction column 26 at a certain flow rate. Move the receiving tube rack 35 through the guide rail 36 to collect the effluent in the basic extract receiving tube 34.

[0034] Step 19, combine the eluents in the neutral extract receiving tube 32, the acidic extract receiving tube 33 and the basic extract receiving tube 34 into a concentration tube, concentrate and make up the volume of the eluent, and perform qualitative or quantitative screening tests.

[0035] Furthermore, if the sample is acidic, extract the sample in the order of acidic, neutral, and basic; if the sample is basic, extract the sample in the order of basic, neutral, and acidic.

[0036] The beneficial effects of the present invention are as follows:

[0037] (1) The present invention provides a solid-phase extraction system that can be used to extract the same sample by neutral, acidic, and basic (or for organic neutral molecules, cations, and anions). After multiple extractions, the extraction liquids are combined, enabling comprehensive extraction of compounds with significantly different properties from each other and performing instrumental detection and analysis at one time.

[0038] (2) This system can also be applicable to using different types of solid-phase extraction columns at the same pH value to extract the same sample multiple times, avoiding significant errors in quantification when sampling and extracting separately and then combining the extraction liquids.

[0039] (3) In order to prevent the loss of compounds that are prone to react with metals (such as tetracycline compounds in water), a layer of polytetrafluoroethylene material is wrapped outside the counterweight at the sample end of the sampling pipeline. This can effectively avoid the destruction of the above chemical substances during the extraction process and ensure the accuracy of the analysis results.

[0040] (4) The solid-phase extraction system of the present invention has the advantages of a wide range of pollutant species covered by extraction, high accuracy, high extraction efficiency, and being convenient for realizing automation. Description of the Drawings

[0041] Figure 1 It is a schematic diagram of the solid-phase extraction system of the present invention, that is, a solid-phase extraction system for extracting the same water sample by neutral, acidic, and basic (or for organic neutral molecules, cations, and anions);

[0042] Figure 2 Schematic diagram of the sample pH value adjustment device.

[0043] Among them, 1 - neutral sample bottle; 2 - acidic sample bottle; 3 - alkaline sample bottle; 4 - sample bottle cap; 5 - weight block with polytetrafluoro - wrapped metal; 6 - oscillator; 7 - oscillator bracket; 8 - pipeline; 9 - injection interface kit; 10 - injection needle kit; 11 - multi - way valve 1; 12 - solvent 1 interface; 13 - solvent 2 interface; 14 - solvent 3 interface; 15 - solvent 4 interface; 16 - solvent 5 interface; 17 - solvent 6 interface; 18 - solvent outlet; 19 - multi - way valve 2; 20 - syringe pump; 21 - sample injection needle bracket; 22 - sample injection needle kit; 23 - solid - phase extraction column tray; 24 - neutral extraction column; 25 - acidic extraction column; 26 - alkaline extraction column; 27 - diversion pipe 1; 28 - diversion pipe 2; 29 - water sample diversion trough; 30 - organic solvent diversion trough; 31 - diversion rack; 32 - neutral extract receiving tube; 33 - acidic extract receiving tube; 34 - alkaline extract receiving tube; 35 - receiving tube rack; 36 - guide rail; 37 - organic waste liquid tank; 38 - waste water tank; 39 - gas pipeline; 40 - solenoid valve 1; 41 - pressure reducing valve; 42 - gas source (air or nitrogen); 43 - pH value adjustment controller; 44 - acid liquid tank; 45 - alkali liquid tank; 46 - solenoid valve 2; 47 - solenoid valve 3; 48 - infusion pump; 49 - solenoid valve 4; 50 - pH value measuring instrument probe 1; 51 - pH value measuring instrument probe 2. Detailed implementation mode

[0044] The technical solutions in the present invention will be further described below with reference to the accompanying drawings:

[0045] This embodiment provides a solid - phase extraction system that can be used for neutral, acidic, and alkaline extraction of samples.

[0046] Figure 1Schematic diagram of a solid-phase extraction system for samples extracted by neutral, acidic, and alkaline methods. In the system, the neutral sample bottles 1, 2, and 3 are made of glass or polytetrafluoroethylene. Neutral sample is placed in neutral sample bottle 1, acidic sample in bottle 2, and alkaline sample in bottle 3. The sample caps 4 have openings in the middle and around. The outer layer of the counterweight 5 is a metal block wrapped with polytetrafluoroethylene. The oscillator 6 is connected to the oscillator bracket 7. There are openings on the oscillator bracket to fix the sample bottles and prevent them from tipping over when the samples are oscillated. The pipeline 8 and other pipelines for liquid transmission in the system are all made of polyether ether ketone (PEEK). The injection interface kit 9 includes an interface connected to the injection pipeline and a sealed interface connected to the injection needle kit 10, and can move left and right or back and forth. The injection needle kit 10 can move up and down according to the position of the sealed interface of the injection interface kit 9. The multi-way valve 11 is a solvent selection valve, with multiple solvent (including pure water) inflow interfaces around. The solvent interfaces 12 - 17 correspond to reagents such as methanol, acetonitrile, dichloromethane, pure water (pure water can also be used as a reagent), formic acid-methanol, ammonia-methanol, etc. The solvent outflow port 18 is where the selected solvent flows out according to needs. The multi-way valve 19 is a control valve for solvent inflow and outflow, water sample inflow and outflow, and gas inflow and outflow. The injection pump 20 can accurately extract a certain amount of water sample and inject the water sample into the solid-phase extraction column through the multi-way valve 19. The loading needle bracket 21 is installed with the loading needle kit 22 and connected to the multi-way valve 19 by a liquid transmission pipeline. The loading needle bracket 21 can move up and down. The loading needle kit 22 facilitates the introduction of the water sample into the solid-phase extraction columns 24 - 26 and seals them. The solid-phase extraction column tray 23 can move left and right or back and forth according to needs, and there are gaps on it to fix the positions of the solid-phase extraction columns 24 - 26. The packing in the neutral extraction column 24 (such as C 18, solid-phase extraction columns such as HLB are suitable for extracting neutral compounds, and the acidic extraction column 25 (such as an anion exchange column like WAX) is suitable for extracting acidic compounds; the basic extraction column 26 (such as cation exchange columns like WCX and SCX) is suitable for extracting basic compounds; the upper end of the first diversion pipe 27 has a funnel-shaped opening, which can introduce the water sample passing through the neutral extraction column 24 into the acidic sample bottle 2 through the infusion pipe. The upper end of the second diversion pipe 28 has a funnel-shaped opening, which can introduce the water sample passing through the acidic extraction column 25 into the basic sample bottle 3 through the infusion pipe. The lower end of the water sample diversion trough 29 has an opening, which introduces the water sample passing through the basic extraction column 26 into the waste water tank 38 through the infusion pipe. The lower end of the organic solvent diversion trough 30 has an opening, which introduces the organic solvent flowing out after activating the solid-phase extraction column into the organic waste liquid tank 37. The diversion frame 31 includes the first diversion pipe 27, the second diversion pipe 28, the water sample diversion trough 29 and the organic solvent diversion trough 30. The neutral extract receiving tube 32, the acidic extract receiving tube 33, and the basic extract receiving tube 34 are made of glass or polytetrafluoroethylene. The receiving tube rack 35 is made of plastic and can fix the extract receiving tubes 32 to 34. The guide rail 36 can move left and right or back and forth as needed, so that the diversion frame 31 and the receiving tube rack 35 fixed on it can move to the required positions. The organic waste liquid tank 37 is made of plastic that is not easily dissolved by organic substances. The waste water tank 38 is made of plastic. 39 is a gas transmission pipe, 40 is the first solenoid valve, and 41 is a pressure reducing valve for providing an air flow with a certain pressure; the gas source 42 is high-pressure air or nitrogen with a purity of ≥99.999%.

[0047] Figure 2 It is a schematic diagram of the sample pH value adjustment device. When adjusting the sample pH value, the pH value adjustment controller 43 can measure the pH value of the water sample and control the solenoid valve switches 46, 47, and 49; the acid liquid tank 44 contains acid liquid; the alkali liquid tank 45 contains alkali liquid; the second solenoid valve 46 controls the acid liquid pipeline switch; the third solenoid valve 47 controls the alkali liquid pipeline switch; the 48 infusion pump provides the conveying power; the fourth solenoid valve 49 controls the flow direction of the acid liquid and the alkali liquid; the pH value measuring instrument probe 50 measures the pH value of the sample in the acidic sample bottle 2, and the pH value measuring instrument probe two 51 measures the pH value of the sample in the basic sample bottle 3.

[0048] The working principle of the present invention is as follows:

[0049] When performing sample extraction, the samples can be extracted in the order of neutral, acidic, and basic samples.

[0050] The first step is to prepare neutral samples: Place the neutral sample bottles 1, 2, and 3 on the oscillator bracket 7 of the oscillator 6 in sequence. Take a certain volume of water sample with a neutral pH value (such as 1 L) and put it into the neutral sample bottle 1, and add a matrix modifier (such as to reduce metal interference in the water sample, add a certain amount of Na2 · An EDTA solution), place the pipeline 8 with a counterweight 5 at the bottom into the neutral sample bottle 1, and cover the sample bottle cap 4.

[0051] The second step is to activate the solid-phase extraction column: Use the syringe pump 20 to sequentially extract 10 mL of organic solvent (this solvent can be the same as the solvent for eluting the solid-phase extraction column), methanol, pure water, and an aqueous solution with the same matrix modifier as added to the water sample through the multi-way valve II 19 and the multi-way valve I 11, and sequentially inject them into the neutral extraction column 24 through the sample injection needle sleeve 22. Move the deflector 31 on the moving guide rail 36, and the outflowing organic solvent is guided into the organic waste liquid tank 37 through the organic solvent diversion trough 30, and the wastewater is guided into the wastewater tank 38 through the water sample diversion trough 29.

[0052] The third step is to load the sample: Use the syringe pump 20 to extract the water sample in the neutral sample bottle 1 through the multi-way valve II 19 and the sample injection needle kit 10, and inject it into the neutral extraction column 24 through the sample injection needle sleeve 22. Control the loading speed at 5 - 10 mL / min, and the outflowing liquid is aligned with the first diversion tube 27 through the moving guide rail 36 to make the water sample flow into the acidic sample bottle 2.

[0053] The fourth step is to wash: Use the syringe pump 20 to extract 10 mL of a solvent or solution (such as pure water) for washing the neutral extraction column 24 through the multi-way valve II 19 and the multi-way valve I 11.

[0054] The fifth step is to dry the solid-phase extraction column: Adjust the pressure of the drying gas flowing out of the gas source 42 with the pressure reducing valve 41, open the solenoid valve I 40, connect the multi-way valve II 19 to the sample injection needle in the sample injection needle kit 22, and dry the neutral extraction column 24 with the outflowing gas.

[0055] The sixth step is to elute: Use the syringe pump 20 to extract a certain volume (such as 10 mL) of a solvent or solution (such as methanol) for eluting the neutral extraction column 24 through the multi-way valve II 19 and the multi-way valve I 11, and pass it through the neutral extraction column 24 at a flow rate of 2 - 3 mL / min. Move the solid-phase extraction column tray 35 left and right or forward and backward through the guide rail 36 to collect the outflowing liquid in the neutral extract receiving tube 32.

[0056] The seventh step is to adjust the pH value of the sample: Set the pH value range to be controlled (such as pH 2 - 3) in the pH value adjustment controller 43. Use the pH value measuring probe I of the pH value adjustment controller 43 to measure the pH value of the sample in the acidic sample bottle 2. Turn on the oscillator 6 to ensure that the added acid solution can be evenly mixed with the water sample. Keep the solenoid valve III 47 closed, open the solenoid valve II 46, the solenoid valve III 49, and the flow pump 48, and let the acid solution drip from the acid solution tank 44 into the acidic sample bottle 2 until the required pH value is reached, then close the solenoid valve II 46, the solenoid valve IV 49, and the flow pump 48.

[0057] Step 8 Activation of the solid-phase extraction column: Move the solid-phase extraction column tray 35 left and right or forward and backward to connect the acidic extraction column 25 to the sampling needle kit 22, and activate the extraction column in the same manner as in Step 2. The activation solvent is selected according to the method requirements.

[0058] Step 9 Sampling: Move the injection interface kit 9 left and right or forward and backward to connect the sampling needle in the sampling needle kit 10 to the acidic sample bottle 2, and sample the acidic extraction column 25 in the same steps as in Step 3.

[0059] Step 10 Washing: Use the syringe pump 20 to draw 10 mL of a solvent or solution such as pure water for washing the acidic extraction column 25 through the multi-way valve II 19 and the multi-way valve I 11.

[0060] Step 11 Drying the solid-phase extraction column: Dry the acidic extraction column 25 in the same steps as in Step 5.

[0061] Step 12 Elution: Use the syringe pump 20 to draw a certain volume (such as 10 mL) of a solvent or solution (such as ammonia-methanol) for eluting the acidic extraction column 25 through the multi-way valve II 19 and the multi-way valve I 11, and pass it through the acidic extraction column 25 at a flow rate of 2 - 3 mL / min. Move the solid-phase extraction column tray 35 left and right or forward and backward to collect the effluent in the acidic extract receiving tube 33.

[0062] Step 13 Adjusting the pH value of the sample: Set the pH value range to be controlled (such as pH 9 - 10) in the pH value adjustment controller 43. Use the pH meter probe II of the pH value adjustment controller 43 to measure the pH value of the sample in the alkaline sample bottle 3. Turn on the oscillator 6 to ensure that the added alkali solution can be evenly mixed with the water sample. Keep the solenoid valve IV 6 closed, open the solenoid valves IV 7 and IV 9 and the flow pump 48, and let the alkali solution drip from the alkali solution tank 45 into the alkaline sample bottle 3 until the required pH value is reached. Then close the solenoid valves IV 7, 49 and the flow pump 48.

[0063] Step 14 Activation of the solid-phase extraction column: Move the solid-phase extraction column tray 35 left and right or forward and backward to connect the alkaline extraction column 26 to the sampling needle kit 22, and activate the extraction column in the same manner as in Step 2. The activation solvent is selected according to the method requirements.

[0064] Step 15 Sampling: Move the sampling interface kit 9 left and right or forward and backward to connect the sampling needle in the sampling needle kit 10 to the alkaline sample bottle 3, and sample the alkaline extraction column 26 in the same steps as in Step 3.

[0065] Step 16 Washing: Use the syringe pump 20 to draw 10 mL of a solvent or solution such as pure water for washing the alkaline extraction column 26 through the multi-way valve II 19 and the multi-way valve I 11.

[0066] Step 17: Dry the solid-phase extraction column: Dry the basic extraction column 26 in the same steps as in Step 5.

[0067] Step 18: Elute: Use the syringe pump 20 to extract a certain volume (such as 10 mL) of the solvent or solution (such as formic acid-methanol) for eluting the basic extraction column 26 through the multi-way valve II 19 and the multi-way valve I 11, and pass it through the basic extraction column 26 at a flow rate of 2-3 mL / min. Move the solid-phase extraction column tray 35 left and right or back and forth to collect the effluent in the basic extract receiving tube 34.

[0068] After the extraction is completed, combine the eluents in the receiving tubes 32, 33, and 34 into a concentration tube, concentrate and volume-fix the eluent to 0.1-1.0 mL using a concentration device such as nitrogen blowing or parallel evaporation, add the internal standard substances of the types under key concern (the internal standard substances are used to judge the mass spectrometry response of the corresponding type of compounds), and perform qualitative and quantitative screening and detection using GC-MS, HPLC-MS / MS, GC-high resolution mass spectrometer, or HPLC-high resolution mass spectrometer.

[0069] If the sample itself is acidic (or basic), the sample can also be extracted in the order of acidic (or basic), neutral, basic (or acidic) samples, and the corresponding solid-phase extraction columns are arranged in the order corresponding to the pH value of the sample.

[0070] If necessary, this system is also applicable to the case of extracting samples using different types of solid-phase extraction columns at the same pH value (such as using HLB / C 18 , anion exchange column, and cation exchange column respectively).

[0071] For the devices described in the various embodiments of the present invention, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A solid phase extraction system suitable for screening unknown pollutants in environmental water samples, comprising three sample bottles placed on an oscillator (6), namely a neutral sample bottle (1), an acidic sample bottle (2) and an alkaline sample bottle (3), an injection interface kit (9), an injection needle kit (10), a multi-way valve (11), a multi-way valve (19), a syringe pump (20), a sample loading needle kit (22), three solid phase extraction columns, namely a neutral extraction column (24), an acidic extraction column (25) and an alkaline extraction column ( 26), a neutral extract receiving tube (32), an acid extract receiving tube (33), and an alkaline extract receiving tube (34) placed on a receiving tube rack (35) for receiving extracts from a solid phase extraction column, respectively; a flow guide rack (31), a guide rail (36) for moving the flow guide rack (31) and the receiving tube rack (35), a flow guide tube 1 (27), a flow guide tube 2 (28), a water sample flow guide trough (29), and an organic solvent flow guide trough (30) placed on the flow guide rack (31); wherein, The injection pipeline (8) of each sample bottle can be selectively connected to the injection needle kit (10) through the injection interface kit (9); The multi-way valve 1 (11) is a solvent selection valve, which is provided with a plurality of solvent inlet interfaces and a solvent outlet (18), and the solvent outlet (18) is connected to the solvent inlet interface selected according to the need; The multi-way valve 2 (19) comprises a plurality of single-channel interfaces and a selection interface, wherein the selection interface is connected to a single-channel interface selected as required; the solvent outflow outlet (18) of the multi-way valve 1 (11) is connected to the first single-channel interface of the multi-way valve 2 (19); the second single-channel interface of the multi-way valve 2 (19) is connected to the injection needle kit (10), and the third single-channel interface of the multi-way valve 2 (19) is connected to the sample needle kit (22); the injection pump (20) selectively draws liquid from the sample bottle through the selection interface of the multi-way valve 2 (19), the second single-channel interface, the injection needle kit (10) and the injection interface kit (9). A certain amount of water sample is taken, and after the selection interface of the second multi-way valve (19) and its third single-channel interface are selected, the extracted water sample is injected into the corresponding solid phase extraction column through the sample loading needle kit (22), and the first guide tube (27) and the second guide tube (28) are respectively used to guide the water sample flowing out of the neutral extraction column (24) and the acid extraction column (25) after the sample is loaded into the corresponding sample bottle; the water sample guide groove (29) is used to guide the water sample flowing out of the alkaline extraction column (26) after the sample is loaded into the waste water tank (38) through the infusion tube, and the organic solvent guide groove (30) is used to guide the organic solvent flowing out after the solid phase extraction column is activated into the organic waste liquid tank (37).

2. The solid phase extraction system according to claim 1, characterized in that: The end of the sample injection pipeline (8) of each sample bottle is provided with a counterweight (5) with an outer layer coated with polytetrafluoroethylene material.

3. The solid phase extraction system according to claim 1, characterized in that: The invention also comprises a gas source (42), a gas pipeline (39), a solenoid valve (40) and a pressure reducing valve (41). The gas source (42) is connected to the fourth single-channel interface of the multi-way valve (19) via the pressure reducing valve (41), the solenoid valve (40) and the gas pipeline (39) in sequence.

4. The solid phase extraction system according to claim 1, characterized in that: The device also comprises a sample pH value adjusting device, which is used for measuring and adjusting the pH value of the sample in the sample bottle.

5. A solid phase extraction method for screening unknown pollutants in environmental water samples implemented by the solid phase extraction system according to any one of claims 1 to 4, characterized in that: First, determine the order of sample extraction. Extract samples in the established order. The following steps 1 to 18 are to extract samples in the order of neutral, acidic, and alkaline. If you need to extract samples in other orders, you should adjust the order of steps accordingly: The first step is to prepare a neutral sample: place three sample bottles, namely, neutral, acidic and alkaline, on an oscillator (6) in sequence, take a certain volume of water sample and put it into a neutral sample bottle (1), and place a sample inlet pipe (8) with a counterweight (5) at the bottom into the neutral sample bottle (1); Step 2: Activate the neutral extraction column (24): Use the syringe pump (20) to sequentially extract the liquid required for activating the solid phase extraction column through the multi-way valve 2 (19) and the multi-way valve 1 (11), and the outflowing liquid is introduced into the organic waste liquid tank (37) or the waste water tank (38); The third step is to load the sample onto the neutral extraction column (24): the water sample in the neutral sample bottle (1) is extracted by a syringe pump (20) through the multi-way valve 2 (19) and the injection needle kit (10), and is injected into the neutral extraction column (24) through the injection needle sleeve (22). The loading speed is controlled at (5)-(10) mL / min, and the guide frame (31) is moved by the movable guide rail (36) so that the guide tube 1 (27) is aligned with the neutral extraction column (24) above, so that the water sample flowing out after the neutral extraction flows into the acid sample bottle (2) through the guide tube 1 (27); Step 4: eluting the neutral extraction column (24): using a syringe pump (20) to extract liquid for eluting the neutral extraction column (24) through the multi-way valve 2 (19) and the multi-way valve 1 (11) to elute the neutral extraction column (24); Step 5, drying the neutral extraction column (24): using the pressure reducing valve (41) to adjust the pressure of the drying gas flowing out of the gas source (42), opening the solenoid valve 1 (40), connecting the multi-way valve 2 (19) to the injection needle in the sample needle kit (22), and using the flowing gas to dry the neutral extraction column (24); Step 6: eluting the neutral extraction column (24): using a syringe pump (20) to extract a certain volume of liquid for eluting the neutral extraction column (24) through the multi-way valve 2 (19) and the multi-way valve 1 (11), passing the neutral extraction column (24) at a certain flow rate, and moving the receiving tube rack (35) through the guide rail (36) so that the effluent is collected in the neutral extract receiving tube (32); Step 7, adjusting the pH value of the water sample flowing out of the acid sample bottle (2) after neutral extraction until the required pH value is reached; Step 8, activating the acidic extraction column (25): connecting the acidic extraction column (25) to the sample loading needle kit (22), selecting an activation solvent as required, and activating the acidic extraction column (25) in the same manner as in the second step; Step 9, loading the acidic extraction column (25): Move the injection interface kit (9) to connect the injection needle in the injection needle kit (10) to the acidic sample bottle (2), load the acidic extraction column (25) in the same manner as in the third step, and allow the water sample flowing out after the acidic extraction to flow into the alkaline sample bottle (3) through the second guide tube (28); Step 10, eluting the acidic extraction column (25): using a syringe pump (20) to extract a solvent or solution for eluting the acidic extraction column (25) through the multi-way valve 2 (19) and the multi-way valve 1 (11) to elute the acidic extraction column (25); Step 11, drying the acidic extraction column (25): drying the acidic extraction column (25) in the same manner as in step 5; Step 12: eluting the acid extraction column (25): using a syringe pump (20) to extract a certain volume of liquid for eluting the acid extraction column (25) through the multi-way valve 2 (19) and the multi-way valve 1 (11), passing the acid extraction column (25) at a certain flow rate, and moving the receiving tube rack (35) through the guide rail (36) to collect the effluent in the acid extract receiving tube (33); Step 13, adjusting the pH value of the water sample flowing out of the alkaline sample bottle (3) after acid extraction until the required alkaline pH value is reached; Step 14, activating the alkaline extraction column (26): connecting the alkaline extraction column (26) to the sample loading needle kit (22), selecting an activation solvent as required, and activating the alkaline extraction column (26) in the same manner as in step 2; Step 15, loading the alkaline extraction column (26): moving the loading interface kit (9) to connect the injection needle in the injection needle kit (10) to the alkaline sample bottle (3), and loading the alkaline extraction column (26); Step 16, eluting the alkaline extraction column (26); Step 17, drying the alkaline extraction column (26); Step 18, eluting the alkaline extraction column (26): using a syringe pump (20) to extract a certain volume of liquid for eluting the alkaline extraction column (26) through the multi-way valve 2 (19) and the multi-way valve 1 (11), passing the alkaline extraction column (26) at a certain flow rate, and moving the receiving tube rack (35) through the guide rail (36) to collect the effluent in the alkaline extract receiving tube (34); In the nineteenth step, the eluates in the neutral extract receiving tube (32), the acidic extract receiving tube (33) and the alkaline extract receiving tube (34) are combined in a concentrator tube, the eluate is concentrated and fixed to a fixed volume, and a qualitative or quantitative screening test is performed.

6. The solid phase extraction method according to claim 1, characterized in that: If the sample is acidic, extract the sample in the order of acidic, neutral, and alkaline; if the sample is alkaline, extract the sample in the order of alkaline, neutral, and acidic.

7. The solid phase extraction method according to claim 1, characterized in that: When eluting each solid phase extraction column, the eluent is passed through each solid phase extraction column at a flow rate of 2-3 mL / min.

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