Active and passive sampling device

Abstract

The utility model belongs to the technical field of water body heavy metal and organic matter pollution monitoring, and particularly relates to an active and passive sampling device which comprises a film coating support, a filter adapter, a liquid sampler and a collector, and the collector is arranged on the support; the collector is provided with an inlet and an outlet; the liquid sampler comprises a sleeve, a first porous sieve plate and a second porous sieve plate are sequentially arranged in the sleeve from top to bottom, and an adsorbent is filled between the first porous sieve plate and the second porous sieve plate; and the filter adapter is communicated with the inlet of the collector through the sleeve. The device is different from a traditional adsorption type sampler, overcomes two defects of gradient diffusion thin film technology (DGT) sampling, and has more sensitive pollutant identification capability. Meanwhile, a traditional passive sampler principle is combined, a microporous structure material is used as a sieve plate, and good stability and a recycling effect are achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of monitoring heavy metal and organic pollution in water bodies, and in particular relates to an active and passive sampling device. Background Art

[0002] The presence of heavy metal ion pollution and organic micropollutants in aquatic environments is worrisome because their long-term effects on aquatic organisms and human health are unknown. Sample collection is the first step in environmental analysis, and active sampling methods have disadvantages such as being time-consuming and labor-intensive, unstable components that are prone to change, and requiring complex pretreatment steps. Passive sampling, as a new method for extracting analytes from the environment, is a new technology for evaluating the free dissolved concentration of analytes based on the adsorption or absorption of pollutants in environmental media such as water, sediment, and soil by polymers. The traditional thin film diffusion gradient DGT passive sampling device consists of a filter membrane, a diffusion membrane, an adsorption membrane, and a plastic jacket that fixes these three membranes. Long-term use will cause a layer of microorganisms to adsorb on the membrane surface, affecting the adsorption effect; and its adsorption curve has certain disadvantages such as hysteresis. Summary of the invention

[0003] The purpose of this utility model is to solve the technical problems existing in the prior art, and to provide a convenient, efficient, affordable and durable active and passive sampling device, which innovatively transforms the permeable film of the traditional passive sampling technology, improves the adsorption efficiency, and avoids the attachment of biofilms. At the same time, the utility model is unique in that it adds a filter membrane that has no adsorption effect on the target pollutants to protect the filler from the influence of microorganisms. Different from the permeable film of the traditional passive sampler, it not only improves the sampling rate, but also avoids the limitations of the shortcomings of the traditional technology.

[0004] Depending on the purpose of the experiment, the liquid sampler can be used to capture organic and inorganic analytes in the water in an active or passive manner through the built-in adsorption filler, and then the enriched analytes can be eluted through devices such as peristaltic pumps.

[0005] In order to achieve the above-mentioned invention object, the utility model adopts the following technical measures:

[0006] An active and passive sampling device, comprising a coating bracket, a filter adapter, a liquid sampler and a collector, wherein the collector is arranged on the coating bracket (a plurality of collectors may be arranged according to actual needs), the collector is provided with an inlet and an outlet, the liquid sampler comprises a sleeve, a first porous sieve plate and a second porous sieve plate are arranged in sequence from top to bottom in the sleeve, an adsorbent is filled between the first porous sieve plate and the second porous sieve plate, and the filter adapter is connected to the inlet of the collector through the sleeve;

[0007] Furthermore, the active and passive sampling device also includes a first glass fiber filter membrane laid on the first porous sieve plate and a second glass fiber filter membrane arranged under the second porous sieve plate.

[0008] Furthermore, a limiting ring is arranged inside the sleeve, and the first glass fiber filter membrane is placed between the limiting ring and the first porous sieve plate.

[0009] Furthermore, the liquid sampler also includes a gland disposed above the limiting ring, and a plurality of filter holes are formed on the gland; the filter adapter is connected to the filter holes through the inlet of the collector.

[0010] Furthermore, grooves are provided on the outer sides of the upper and lower ends of the liquid sampler sleeve, and O-rings are installed inside the grooves to tightly fit the sleeve and the collector outside it.

[0011] Furthermore, the collector and the coating bracket have two installation methods. The first method is: the coating bracket is a non-supporting PTFE coating bracket, the collector is a built-in collector, and the upper part of the built-in collector has an outer ring, which is fixed to the non-supporting PTFE coating bracket with screw holes by screws;

[0012] The second method is: the coating bracket is a supporting PTFE coating bracket, and the collector is an independent collector, which can be directly supported on the supporting plate of the supporting PTFE coating bracket.

[0013] Compared with the prior art, the utility model has the following advantages and beneficial effects:

[0014] (1) The sampler of the utility model is light and compact, suitable for carrying;

[0015] (2) Low price and reusable;

[0016] (3) It can realize the simultaneous and stable determination of multiple index pollutants such as common heavy metal ions and organic matter, with high determination capacity and strong environmental resistance;

[0017] (4) This device is different from the traditional adsorption sampler. It overcomes the two major drawbacks of gradient diffusion film technology (DGT) sampling and has a more sensitive pollutant identification capability. It can monitor μg·L -1 Even ng L -1 The concentration level of pollutants can meet more than 90% of the pollutant monitoring needs. At the same time, it combines the traditional passive sampler principle and microporous structure materials as the sieve plate, which has good stability and reuse effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a simplified structural diagram of the liquid sampler of the utility model;

[0019] Figure 2 This is a schematic diagram of the structure of the liquid sampler body of the utility model (unit: mm);

[0020] Figure 3 This is a schematic diagram of the assembly structure of the overall sampling system of the utility model (front view);

[0021] FIG4 is a schematic diagram of the internal structure of the liquid sampling adsorption device and a diagram of disassembled accessories;

[0022] FIG5 is a schematic diagram of two installation methods of the collector and the coating support;

[0023] Figure 6 Schematic diagram of assembling the air exhaust device for the liquid sampler;

[0024] Figure 7 It is the enrichment curve of the target substance between the water phase and the absorption phase in the first-order kinetic model proposed by Huckins et al. in 1993;

[0025] Figure 8 In Example 2, the number of days of experiment is taken as the horizontal axis, and the Cd 2+ The mass of metal ions is the ordinate, and the trend graph of 7-day passive sampling of high-concentration cadmium ions;

[0026] Fig. 9 In Example 2, the number of experimental days is the horizontal axis, and the Cd in the sampler is 2+ The mass of metal ions is the ordinate, and the trend graph of 7-day passive sampling of low-concentration cadmium ions;

[0027] in:

[0028] 1-filter adapter; 2-liquid sampler; 3-built-in collector; 4-clip; 5-sample bottle; 6-hydrophilic sieve plate; 7-conductive hose; 8-peristaltic pump; 2-1-first porous sieve plate; 2-2-second porous sieve plate; 2-3-limiting ring; 2-4-pressure cover; 2-5-O-ring; 9-wrench socket; 10-unsupported PTFE-coated bracket; 11-supported PTFE-coated bracket; 12-independent collector; 13-adapter. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0030] See also Figure 1-5, the utility model provides an active and passive sampling device with a microporous structural material as a filter membrane, which includes a coating bracket, a filter adapter 1, a liquid sampler 2 and a collector, wherein a plurality of collectors are provided, and the plurality of collectors are supported on the coating bracket, the liquid sampler 2 includes a sleeve and a first porous sieve plate 2-1 and a second porous sieve plate 2-2 placed inside the sleeve from top to bottom, wherein a first glass fiber filter membrane is placed above the first porous sieve plate 2-1, an adsorbent filler is placed between the first porous sieve plate and the second porous sieve plate 2-2, and a second glass fiber filter membrane is placed below the second porous sieve plate 2-2, the collector is provided with an inlet and an outlet, and the filter adapter is connected to the inlet of the collector through the sleeve. The collector outlet is connected to an external collection container through a peristaltic pump 8 via a conductive hose 7.

[0031] In this embodiment, in order to ensure that the liquid sampler 2 and the collector are tightly nested, grooves are opened on the outside of the upper and lower ends of the sleeve, and O-rings are installed inside the grooves to fit the sleeve and the external collector tightly.

[0032] In order to better fix the components in the liquid sampler 2, a limit ring 2-3 is placed above the first glass fiber filter membrane inside the sleeve. The limit ring 2-3 can be designed in different models and sizes, and limit rings 2-3 of different heights can be selected according to the thickness of the adsorbent filler after compaction. To further ensure that the components in the liquid sampler 2 do not turn over, a pressure cap 2-4 is detachably installed above the limit ring 2-3 inside the sleeve, and a plurality of filter holes are opened on the pressure cap 2-4; the filter adapter is connected with the filter hole through the inlet.

[0033] In the present invention, the collector and the coating bracket can be installed in two ways. Assembly method 1: The coating bracket is a non-supporting PTFE coating bracket 10. In this case, the two are connected in the following way: the collector is a built-in collector 3, which has an outer ring on the upper part, which is fixed to the non-supporting PTFE coating bracket 10 with screw holes by screws;

[0034] Assembly method 2: The coating support is a supporting PTFE coating support 11. In this case, the collector is an independent collector 12, which can be directly supported on the supporting plate of the supporting PTFE coating support 11 (see FIG. 5).

[0035] The sampler sieve plate in the utility model is filtered by microporous structural materials. Different from permeable films, microporous structural materials can attach heavy metal films on their surfaces to prevent the formation of microbial films due to their toxicity, thereby avoiding the influence of adsorption efficiency. Two porous sieve plates are selected and arranged on the upper and lower sides of the adsorbent to support the adsorbent. A layer of 0.45μm glass fiber filter membrane can be added to the outside of the sieve plate to protect the adsorbent filler. The additional limiting ring will not make the adsorbent too loose and lose with the impact of the water flow.

[0036] In the following implementations, see Figure 3 The top of the filter adapter 1 is connected to the sample loading bottle 5, and the two are connected by a buckle 4. A hydrophilic sieve plate 6 is installed between the filter adapter 1 and the sample loading bottle 5 to initially filter the sampled water (a layer of 0.2 μm microporous water filter membrane can be covered to prevent the hydrophilic sieve plate from floating); the liquid sampler 2 is connected to the inside of the filter adapter 1 at the top, and the lower part is nested in the built-in collector 3, and then the outlet of the built-in collector 3 is connected to a conductive hose 7 with an inner diameter of 3 mm and a wall thickness of 1 mm to elute the sample into a collection container through a peristaltic pump 8.

[0037] See also Figure 2 4 , in this embodiment, the top inner diameter of the sleeve is 20 mm, the bottom inner diameter is 16 mm (the 4 mm inner ring serves as a supporting structure for internal assembly), and the first glass fiber filter membrane and the second glass fiber filter membrane are both 0.45 μm glass fiber filter membranes.

[0038] In this embodiment, the matching wrench sleeve 9 is used to assist the liquid sampler 2 in installing the first porous sieve plate 2-1 and the second porous sieve plate 2-2, the limit ring 2-3, and the gland 2-4. The seven holes on the surface of the gland 2-4 form a complementary structure with the protruding part of the matching wrench sleeve 9. In this form, the gland can be rotated and fixed to the upper thread of the sampler by using the wrench sleeve to complete the assembly of the sampling device.

[0039] Referring to Fig. 4, the inner cavity assembly structure of the liquid sampler 2 is adopted to avoid the adsorption deviation of the target pollutant due to environmental factors, and the hollow cylinder design is adopted to reduce the water resistance. In the utility model, when actually used, firstly, a layer of 0.45 μm glass fiber filter membrane is placed at the bottom of the sleeve; then the second porous sieve plate 2-2 is placed, and then the required adsorbent filler is placed. Different adsorbent fillers can be selected according to different pollutants. In the test stage of the sampling system of the utility model, analytical grade Chelex 100 sodium chelating resin (200-400 mesh) is selected for adsorption of heavy metal ions, and HLB (divinyl / N-vinyl pyrrolidone, average particle size 40-60 μm) is selected as the adsorbent filler for adsorption of organic pollutants, both of which can achieve good adsorption effect. A layer of porous sieve plate, namely the first porous sieve plate 2-1, still needs to be added on top of the adsorbent filler to compress the adsorbent filler; finally, a layer of 0.45 μm glass fiber filter membrane needs to be placed. The two outermost filter membranes are used to protect the adsorbent filler, thereby avoiding contamination by impurities in the wild water body. The top is fixed with a limiting ring 2-3 to ensure that the adsorbent filler will not be dispersed by the water flow, and the built-in adsorbent filler can stably adsorb the analyte in the environment. Finally, the pressure cover 2-4 is fixed with the matching tool wrench socket 9 to complete the assembly of the liquid sampler 2.

[0040] See also Figure 6Before the liquid sampling system starts to load the sample, the assembled liquid sampler 2 needs to be evacuated. In this embodiment, an independent collector 12 is nested at the top and bottom of the liquid sampler 2. The outlet of the independent collector 12 near the top (the end of the gland 2-4) of the liquid sampler 2 is connected to a 10mL syringe (without the needle) adapter 13; the outlet of the independent collector 12 near the bottom (the filter membrane end) of the liquid sampler 2 is placed in pure water. Use a syringe to start extracting pure water. When pure water is sucked into the syringe, stop extracting, remove the syringe, and then take out the liquid sampler 2 nested in the two independent collectors 12 and put it into pure water to complete the air exhaust step.

[0041] See also Figure 7 , driven by the chemical potential difference, the target pollutant migrates from the water phase to the passive sampling device by passive diffusion. The first-order kinetic model proposed by Huckins et al. in 1993 can describe the enrichment process. According to the characteristics of the sampling process, the accumulation process of the target substance in the sampler can be divided into Figure 7 The three stages shown are: linear enrichment stage, curve enrichment stage and equilibrium enrichment stage. The sampling process of the embodiments of the utility model patent is relatively short and all belong to the linear enrichment stage.

[0042] In the following embodiments, the filter adapter 1, the liquid sampler 2 sleeve, the collector, the limit rings 2-3, and the pressure caps 2-4 in the liquid sampling system are all made of PTFE. PTFE, as a functional polymer material in the industrial field, can be used for non-stick coatings to withstand high temperatures and corrosion, and can be applied to various water environments.

[0043] The liquid sampler 2 provides a high-precision internal cavity and corresponding accessories, and is placed in the water body by an inner cavity assembly method. The water body contacts the adsorbent exposed in the sampler window by flow rate, avoiding human or aquatic organisms from affecting the adsorption process of the target pollutants, thereby causing adsorption errors.

[0044] The present invention is further described in detail below in conjunction with specific embodiments:

[0045] Sampler field performance and initial application:

[0046] The liquid sampler 2 of the utility model is placed in outdoor water bodies and simulated water bodies to collect heavy metals and organic pollutants therein and evaluate its performance in actual environments.

[0047] The sampling process of the liquid sampling system can select the sampling-testing process according to the target pollutants to be measured.

[0048] Heavy metals; exhaust air - activation - active sampling / passive sampling - membrane removal - elution - sample measurement.

[0049] Organic matter: exhaust air - activation - active sample loading / passive sampling - membrane removal - freeze drying - elution - concentration - sample testing.

[0050] Example 1

[0051] Example of active sampling of heavy metals (South Lake water);

[0052] This embodiment provides an example of active sampling and analysis of trace divalent metal ions in water, which can well characterize the risks of water pollutants.

[0053] 1.1 Sampling

[0054] Use a 1L plexiglass sampler to continuously collect 5L of Nanhu water. Be careful to avoid metal products during the collection process.

[0055] 1.2 Filtering

[0056] Instruments and consumables: Jinteng model T-50.1L, solvent filter with a filter head pore size of 10μm, and a diaphragm vacuum pump for auxiliary filtration; 15cm double-circle medium-speed qualitative filter paper from General Electric Biotechnology (Hangzhou) Co., Ltd. and Jinteng 0.2μm and 0.45μm microporous filter membranes (water system); 15mL centrifuge tubes.

[0057] Pretreatment steps before heavy metal recovery in water:

[0058] 1. Primary filtration: The collected water samples are filtered through a 15 cm double-circle medium-speed qualitative filter paper;

[0059] 2. Precision filtration: first pass through a 0.45μm microporous water filter membrane, then pass through a 0.2μm microporous water filter membrane.

[0060] 1.3 Sampler to recover heavy metals in water

[0061] Instruments and consumables: peristaltic pump BT100-L, pump head DG-6 or DG-12 (6 channels or 12 channels), 3*1 (inner diameter 3mm, wall thickness 1mm) or 16# (inner diameter 3.2mm, wall thickness 1.6mm) hose.

[0062] Chelex100 sodium chelating resin (200-400 mesh) is used as adsorbent filler to recover divalent metal ions in water.

[0063] The loading bottle 5 can be connected to the liquid sampler 2 according to actual conditions. In this embodiment, the pretreated water is placed in the loading bottle 5, and the loading bottle 5 is connected to the filter adapter 1 through the buckle 4. In order to further ensure the sample filtering effect, a layer of hydrophilic sieve plate 6 can be placed between the loading bottle 5 and the filter adapter 1 for preliminary filtration, and a layer of 0.2μm microporous water filter membrane can also be covered to prevent the hydrophilic sieve plate 6 from floating.

[0064] Follow these steps in order:

[0065] (1) Assemble the liquid sampler 2: Place a 0.45 μm glass fiber filter membrane, a second porous sieve plate (5 μm pore size, PP material), 0.5 g Chelex100 sodium chelating resin, a first porous sieve plate (5 μm pore size, PP material), a 0.45 μm glass fiber filter membrane, and a limit ring 2-3 in the sleeve in sequence, and finally use a wrench socket 9 to cover the pressure cover 2-4.

[0066] (2) Exhaust air: nest the assembled liquid sampler 2 into two independent collectors 12, install the syringe adapter 13 at the water outlet of the independent collector at the end of the pressure cap 2-4, put the water outlet of the independent collector 12 at the filter membrane end into pure water, slowly pull the upper syringe, and stop pulling when pure water enters the syringe. Remove the syringe, adapter 13 and independent collectors 12 at both ends in turn, and then soak the liquid sampler 2 in pure water for use.

[0067] (3) According to Figure 3 The assembly of the active and passive sampling device is completed. When assembling the present embodiment, the collector selects the built-in collector 3 and connects it with the unsupported PTFE coated bracket 10 .

[0068] (4) Activation: According to the number of peristaltic pump channels, a corresponding number of active and passive sampling devices can be set to carry out multi-channel sample enrichment and recovery. In this embodiment, 6 groups of experiments are set (5 parallel test groups and one blank test group), and 10 mL of 0.5 mol / L CH3COONH4 is added to each of the 6 sample loading bottles 5. In order to prevent the filter membrane from being damaged, the peristaltic pump flow rate is set to 1.5 mL / min. After being turned on, the sample is drained for activation.

[0069] (5) Sampling: 500 mL of the water filtered in step 1.2 was added to the sample bottle 5 of the five parallel test groups. 500 mL of pure water was added to the sample bottle 5 of the blank test group. The peristaltic pump flow rate was set to 1.5 mL / min to prevent damage to the filter membrane, and the pump was dried after it was turned on.

[0070] (6) Membrane removal: After removing the liquid sampler 2, use the wrench socket 9 and tweezers to help clamp out the glass fiber filter membranes at both ends of the liquid sampler 2, and then put the liquid sampler 2 back.

[0071] (7) Washing: Add 10 mL of pure water to the sample bottle 5 for each of the six test groups, set the peristaltic pump flow rate to 5 mL / min, and start the pump to drain. The liquid extracted in the above steps is treated as waste liquid.

[0072] (8) Elution: 10 mL of 5% HNO3 was added to the sample bottle 5 for all six test groups. The peristaltic pump flow rate was set to 5 mL / min. After it was turned on, it was pumped dry to complete the elution. The eluate was collected in a 15 mL centrifuge tube.

[0073] 1.4 Sample analysis

[0074] ICP-OES is used to analyze the heavy metal content of the eluate, and the concentration of heavy metals in the water can be calculated based on the concentration coefficient.

[0075] 1.5 Results Analysis

[0076] The ICP-OES was used to detect the contents of four metal ions, namely cadmium, lead, chromium and copper, in the eluents collected from each test group. After analysis, it was found that the contents of the four heavy metals adsorbed on the liquid sampler 2 were based on the concentration factor of this active sampling experiment (sample volume 500mL / eluent volume 10mL) = 50. The heavy metal content in the water of Nanhu Lake sampled this time can be calculated according to heavy metal content = detection value / concentration factor (Table T1), and then the next step of analysis and research can be carried out (it has been verified in the present utility model that the heavy metals can be completely eluted during the above elution process).

[0077] Table T1 Statistical characteristics of heavy metal content in Nanhu Lake water (unit: μg·L -1 )

[0078]

[0079] Example 2

[0080] Heavy metal passive sampling verification example - 7-day experiment (select cadmium ion determination):

[0081] Materials: 10 2L transparent glass jars, Chelex 100 sodium chelating resin (200-400 mesh) adsorbent filler, 15mL centrifuge tubes.

[0082] 2.1 Preparation

[0083] (1) 10 glass cylinders, 9 of which are filled with 1 L of pure water, and a blank glass cylinder is set, labeled No. 10, and the remaining 9 are labeled in sequence and set to a concentration of 5 ppb (5 μL of a single-label solution of divalent cadmium ions with a single-label concentration of 1000 ppm is added to each glass cylinder), and are labeled No. 1-9;

[0084] (2) In this embodiment, three parallel liquid samplers 2 are arranged in each numbered glass cylinder, and a total of 30 liquid samplers 2 are required.

[0085] 2.2 Heavy metals in sampler recovery standard samples (7 days)

[0086] After 30 liquid samplers 2 are activated according to the method of steps (1)-(4) in 1.3 of Example 1, the peristaltic pump 8 is started to continue to add a small amount of pure water to the liquid sampler 2 to ensure that the liquid sampler 2 is moistened (that is, pure water flows out from the collector connected to the peristaltic tube), and then the 30 liquid samplers 2 are taken out and evenly placed horizontally in 10 glass cylinders to start passive sampling.

[0087] The liquid samplers 2 in glass jars No. 1 and No. 2 are subjected to membrane removal, elution and washing according to steps (6)-(8) in 1.3 of Example 1 at 0.25 d (6 h) and 0.5 d (12 h), and the liquid samplers 2 in the remaining glass jars are subjected to membrane removal, elution and washing at 1 d (24 h)-7 d (168 h), respectively. Every 24 h, only the liquid samplers 2 in one of the glass jars are subjected to membrane removal, elution and washing, while the liquid samplers 2 in the other glass jars remain unchanged. At the same time, the liquids in the other glass jars are replaced with the liquids before sampling.

[0088] like:

[0089] In this embodiment, the liquid samplers 2 of all glass cylinders start sampling at 9:00 on the first day. The liquid sampler 2 in glass cylinder No. 1 is rinsed and eluted at 15:00 on the first day, and the liquid sampler 2 in glass cylinder No. 2 is rinsed and eluted at 21:00. The liquid samplers 2 in glass cylinders No. 3-10 remain unchanged. The liquid in glass cylinders No. 3-10 is replaced with the same liquid as before the start of sampling, and passive sampling continues.

[0090] At 9:00 on the next day, the membrane was removed, eluted and the liquid sampler 2 in the No. 3 glass cylinder was washed, and the liquid samplers 2 in the No. 4-10 glass cylinders remained unchanged. The liquid in the No. 4-10 glass cylinders was replaced with the same liquid as before the sampling started, and passive sampling continued;

[0091] On the third day at 9:00, wash and elute the liquid sampler 2 in glass jar No. 4, and the liquid sampler 2 in glass jars No. 5-10 remains unchanged. Replace the liquid in glass jars No. 5-10 with the same liquid as before the start of sampling, and continue passive sampling; and so on, starting at 9:00 every day, remove the membrane and rinse the samplers in the corresponding glass jars. On the last day, remove the membrane and rinse the samplers in glass jars No. 9 and No. 10 according to the above steps. After each elution, collect the corresponding eluate and mark it.

[0092] 2.3 Sample analysis

[0093] ICP-OES was used to analyze the content of heavy metals in the eluent, and the concentration of heavy metals in the standard sample was calculated based on the concentration factor.

[0094] 2.4 Results Analysis

[0095] The accumulation process of the passive sampler can be divided into the following two types according to the characteristics of the sampling process: Figure 7 The three stages shown are: linear enrichment stage, curve enrichment stage and equilibrium enrichment stage (from Huckins JN, Manuweera GK, Petty JD, et al. Lipid-containing semipermeable membrane devices for monito-ring organic contaminants in water [J]. Environmental Science & Technology, 1993, 27 (12): 2489-2496.) When the sampling time is short, that is, the linear enrichment stage, the sampling quality increases linearly with the increase of time, and the dynamics between the receiving phase and the water phase can be simulated by a first-order mathematical model.

[0096] Passive sampling experiment selection Cd 2+ Metal ions were used as the analysis object and analyzed according to the above experimental steps combined with the sample data. 2+ The mass of metal ions (detection concentration value × eluent volume) is used as the ordinate, and the trend of cadmium ion passive sampling for 7 days is plotted ( Figure 8 ), the linear fit is 0.95. The experimental period is set to 7 days, which is consistent with the first stage of sampling (kinetic stage), according to formula (1):

[0097] N s (t) = C bulk ·R s t (1)

[0098] The sampling rate R of liquid sampler 2 is calculated as s Where N s (t) represents the mass of the analyte on the filler, μg; C bulk Indicates the concentration of the analyte in water, μg·L -1 ; R s represents the sampling rate, mL / d; t represents the sampling time, days.

[0099] according to Figure 8 The fitting curve y = 0.0393x, the slope 0.0393 represents the average daily increase in the adsorbed cadmium ion mass (0.0393 μg / d), so R s for:

[0100]

[0101] Based on the R measured during the passive sampling verification phases The water concentration can be inferred from future water sampling to facilitate water environment monitoring.

[0102] 2.5 Low-concentration 7-day passive sampling experiment (selecting cadmium ion determination)

[0103] The same low concentration (100ppt) 7-day blue-capped bottle passive sampling experiment was carried out as in steps 2.1-2.3 of Example 2. During the experiment, except for injection and sampling, the blue-capped bottle was kept sealed to play a good dust-proof role. The specific steps are as follows:

[0104] 2.5.1 Preparation

[0105] (1) 9 blue-capped bottles, 8 of which are filled with 1 L of pure water, and a blank blue-capped bottle is set, numbered 9, and the remaining 8 are numbered in sequence and set to a concentration of 100 ppt (ng·L -1 ) (Add 0.1 μL of 1000ppm divalent cadmium ion single-label solution to each blue-cap bottle), numbered 1-8;

[0106] (2) In this embodiment, two parallel liquid samplers 2 are arranged in each numbered glass cylinder, and a total of 18 liquid samplers 2 are required.

[0107] 2.5.2 Heavy metals in sampler recovery standard samples (7-day low concentration)

[0108] After all 18 liquid samplers 2 are activated according to the method of steps (1)-(4) in 1.3 of Example 1, a small amount of pure water is continued to be added to the liquid sampler 2 to ensure that the liquid sampler 2 is moistened (when pure water flows out from the place where the collector is connected to the peristaltic tube), and then they are evenly placed horizontally into 9 blue-capped bottles to start passive sampling.

[0109] The liquid sampler 2 in the blue-capped bottle No. 1 was taken out 10 minutes after being placed in the blue-capped bottle, and the liquid samplers 2 in the blue-capped bottles No. 2-9 were taken out after being placed in the blue-capped bottle at 24h, 48h, 72h, 96h, 120h, 144h, and 168h respectively (a total of 7 days), and the membrane was removed, rinsed, and eluted according to steps (6)-(8) in 1.3 of Example 1. Each time, only the liquid sampler 2 in one of the blue-capped bottles was removed, rinsed, and eluted. On Day 7, the liquid samplers 2 in the blue-capped bottle No. 8 and the blank blue-capped bottle No. 9 (blank sample control group) were removed, rinsed, and eluted according to the above steps. After each elution, the corresponding eluate was collected and marked.

[0110] This experiment does not require replacing the liquid in the blue-cap bottle every day. At the same time, the water temperature in the blue-cap bottle must be maintained at 23℃-25℃.

[0111] 2.5.3 Sample analysis

[0112] ICP-MS was used to analyze the content of heavy metals in the eluent, and the concentration and mass of heavy metals in the standard sample were calculated based on the concentration factor.

[0113] 2.5.4 Result Analysis

[0114] Low concentration passive sampling experiment selected Cd 2+ Metal ions were used as the analysis object and analyzed according to the above experimental steps combined with the sample data. 2+ The mass of metal ions is the ordinate, and the trend of 7-day passive sampling of low-concentration cadmium ions is plotted ( Fig. 9 ), the linear fit is 0.99. The experimental period is set to 7 days, which is consistent with the first stage of sampling (kinetic stage). According to formula (1) and Fig. 9 The fitting curve y = 0.9624x gives R s It is 9.6mL / d.

[0115] Example 3

[0116] Refer to the method of Example 2 above to carry out active sampling of organic matter (select atrazine, β-chloronaphthalene C 10 Determination of 6 organic pollutants including H7Cl, metazolam, anthracene, carbamazepine and pyrene).

[0117] Six groups of samples were prepared, of which five were parallel sample groups, each of which was added with the above six organic substances, and the concentration of each organic substance was 100 ppt, and the other was a blank control group (only pure water was added). Each group of solutions was adjusted to a pH value of about 2 with 1 mol / L HCl before use;

[0118] 3.1 Sampler recovery of organic matter in standard samples

[0119] Instruments and consumables: peristaltic pump BT100-L, pump head DG-6 or DG-12 (6 channels, or 12 channels), 3*1 (inner diameter 3mm, wall thickness 1mm) or 16# (inner diameter 3.2mm, wall thickness 1.6mm) hose; Christ ALPHA 2-4 LD plus freeze dryer; Christ RVC 2-25 CD plus vacuum centrifugal concentrator.

[0120] 3.2 Recovery of organic matter from standard samples using HLB (40-60 μm) adsorbent filler

[0121] Configuration of standard samples:

[0122] (1) Configure 6 types of target pollutants 5000ppm, 2mL single standard

[0123] 10 mg of each of the six types of target pollutants were weighed, 2 mL of acetone (chromatographic grade) was added to 5 mL centrifuge tubes, and after ultrasonic dissolution, the samples were stored in 2 mL glass bottles (a total of 6 glass bottles).

[0124] (2) Prepare 1ppm, 20mL mixed standard stock solution

[0125] Prepare a 50 mL glass bottle, take 4 μl of each of the 6 target single markers from step (1) and add it, then add acetone to 20 mL, mix well and place in a -20°C refrigerator.

[0126] (3) Prepare 100ppt, 500mL standard sample

[0127] Prepare a 500mL beaker, take out 50μL of the 1ppm mixed standard mother solution in step (2) and add it to it, then add pure water to 500mL, mix well to obtain the standard sample, and set aside.

[0128] Refer to steps (1) to (4) of Example 1 1.3 for assembly, air exhaust and activation. The difference is that during activation in this example, 6 mL of methanol and 6 mL of water were added to each of the six test groups, the peristaltic pump flow rate was set to 1 mL / min, the mixture was pumped dry for activation, and then the following steps were performed.

[0129] (1) Sampling: For each of the five parallel test groups, add 100 mL of standard sample to the sample bottle 5. For the blank test group, add 100 mL of pure water to the sample bottle 5. Set the peristaltic pump flow rate to 2.5 mL / min, turn it on, and drain. Then, add 6 mL of pure water to each liquid sampler 2 and drain it to remove possible salts.

[0130] (2) Freeze drying: remove all liquid samplers 2 and place them in a -20°C refrigerator for one night (12 hours), then place them in a freeze dryer for 5 hours to dry the fillers therein.

[0131] (3) Elution: 15 mL of methanol was added to the sample bottle 5 of each of the six experimental groups. The flow rate of the peristaltic pump was set to 1 mL / min. The eluate was collected by pumping and placed in a 15 mL centrifuge tube. The centrifuge tube was removed from the cap and placed in a concentrator to be concentrated to 2 mL. 15 mL of dichloromethane was added to the sample bottle 5 of each experimental group. The flow rate of the peristaltic pump 8 was set to 1 mL / min and the eluate was pumped. The eluate was concentrated to 2 mL using a concentrator.

[0132] (4) Re-concentration: Mix the methanol concentrate and the dichloromethane concentrate after each concentration, and continue to concentrate each liquid until it is dry (no liquid in the centrifuge tube); then add 2 mL of n-hexane to each centrifuge tube for mutual dissolution, and then continue to concentrate to 200 μL for use.

[0133] (5) Passing through a membrane: Since some organic solvents and water have good mutual solubility, each group of liquid after concentration needs to be passed through a desiccant anhydrous sodium sulfate (using a 0.22 μm water filter membrane) and then fixed to 1 mL with n-hexane to obtain the collected liquid. If stratification occurs, centrifugation can be considered. If no stratification occurs, the liquid can be directly tested on the machine.

[0134] 3.2 Sample analysis

[0135] GC-MS is used to analyze the content of organic matter in the collected liquid. Based on the concentration factor, the concentration of organic matter in the standard sample can be calculated, thereby knowing the recovery rate of pollutants adsorbed by the liquid sampler 2.

[0136] 3.3 Results Analysis

[0137] The adsorption data of the six organic pollutants on the liquid sampler 2 were detected. According to the 100mL concentration (100ppt) set by the standard sample, the theoretical recovery value is 10ppb. Using the ratio of the measured organic concentration to the theoretical value, the recovery rate of each organic pollutant (Table T2) is 80%-90%, which shows that the liquid sampler 2 has a stable and good adsorption rate.

[0138] Table T2 Organic Pollution Recovery Rate (Unit %)

[0139]

[0140] Example 4: Active loading of heavy metals and organic matter

[0141] Heavy metal selection Cd 2+ As the target pollutant to be measured, atrazine is selected as the target pollutant to be measured for organic matter. Ten groups of liquid samplers 2 are prepared, and two liquid samplers 2 are prepared in each group, for a total of 20.

[0142] 4.1 Sampler recovery of heavy metals and organic matter in standard samples

[0143] The 10 groups of liquid samplers 2 were assembled and vented according to the method of steps (1)-(3) in 1.3 of Example 1, with the following differences: the liquid samplers 2 of groups 1-6 were filled with 0.5g of two fillers (Chelex100 on the upper layer, HLB on the lower layer, and a porous sieve plate between the two); then the liquid samplers 2 of groups 1-2 were activated according to the method of step (4) in 1.3 of Example 1; the liquid samplers 2 of groups 3-4 were activated according to the activation steps of Example 3; after the activation steps of step (4) in 1.3 of Example 1, groups 5-6 were activated again according to the activation steps of Example 3. (Groups 1-2 were used as the control group for heavy metal recovery, and groups 3-4 were used as the control group for organic matter recovery). Then the following operations were performed:

[0144] (1) Sample loading: Add 50 mL of 500 ppt Cd to group 1-2 2+ Add the single-label solution to sample bottle 5. For groups 3-4, add 50 mL of 500 ppt atrazine single-label solution to sample bottle 5. For groups 5-6, add 50 mL of 500 ppt Cd 2+ Add the single-label solution and 50 mL of 500 ppt atrazine single-label solution into sample bottle 5. To prevent the filter membrane from being damaged, set the peristaltic pump flow rate to 1.5 mL / min and drain after turning it on.

[0145] (2) Disassembly of membrane: After removing the liquid sampler 2, use the wrench socket 9 and tweezers to help clamp out the glass fiber filter membranes at both ends of the sampler, and then reassemble the liquid sampler 2.

[0146] (3) Washing: Add 10 mL of pure water to the sample bottle 5 for both the 1-2 and 5-6 test groups, set the peristaltic pump flow rate to 5 mL / min, and start the pump to drain. The liquid extracted in the above steps is treated as waste liquid.

[0147] (4) Elution: Add 10 mL of 5% HNO3 to the sample bottle 5 for both the 1-2 group and the 5-6 group test groups, set the peristaltic pump flow rate to 5 mL / min, start it and pump dry to complete the elution; then collect the eluate in a 15 mL centrifuge tube.

[0148] After the above steps, the liquid samplers 2 of the test groups 5-6 and the liquid samplers 2 of the groups 3-4 continue to perform freeze-drying, elution, re-concentration and membrane filtering to complete the collection of the collected liquid with reference to steps (2) to (5) of 3.1 of Example 3.

[0149] 4.2 Sample analysis

[0150] ICP-MS was used to analyze the content of heavy metals in the eluents of test groups 1-2 and 5-6, and the concentration of heavy metals in the standard samples was calculated based on the concentration factor. GC-MS was also used to analyze the content of organic matter in test groups 3-4 and 5-6, and the concentration of organic matter in the standard samples was calculated based on the concentration factor, so as to know the recovery rate of pollutants adsorbed by the liquid sampler.

[0151] 4.3 Results Analysis

[0152] Target analyte of heavy metals: Cd 2+ The adsorption of atrazine, the target analyte of pollutants and organic matter, on the liquid sampler was detected. Groups 1-2 were used as the heavy metal control group for the two types of pollutants to be adsorbed and eluted together, and groups 3-4 were used as the organic control group for the two types of pollutants to be adsorbed and eluted together. According to the set loading of 50mL500ppt (ng·L -1) Two types of pollutant standards and 10mL of heavy metal eluent, 1mL of organic collection solution, it can be seen that the theoretical recovery concentration of heavy metals is 2.5ppb, and the theoretical recovery concentration of organic matter is 25ppb. The concentration measured on the machine / theoretical recovery concentration can finally calculate the recovery rate comparison of the two types of pollutants.

[0153] Table T3 Recovery rate of two types of pollutants (unit %)

[0154]

[0155] Both types of pollutants have good recovery rates, and the interference between the two types of pollutants is relatively small. Therefore, it can be concluded that the liquid sampler 2 of the utility model has good stability in the co-adsorption and elution of heavy metals and organic matter.

[0156] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An active and passive sampling device, characterized in that: The active and passive sampling device includes a coating bracket, a filter adapter, a liquid sampler and a collector, wherein the collector is arranged on the coating bracket; the collector is provided with an inlet and an outlet; the liquid sampler includes a sleeve, wherein a first porous sieve plate and a second porous sieve plate are arranged in sequence from top to bottom in the sleeve, and an adsorbent is filled between the first porous sieve plate and the second porous sieve plate; the filter adapter is connected to the inlet of the collector through the sleeve.

2. The active and passive sampling device according to claim 1, characterized in that: The active and passive sampling device also includes a first glass fiber filter membrane laid on the first porous sieve plate and a second glass fiber filter membrane arranged under the second porous sieve plate.

3. The active and passive sampling device according to claim 2, characterized in that: A limiting ring is arranged inside the sleeve, and the first glass fiber filter membrane is placed between the limiting ring and the first porous sieve plate.

4. The active and passive sampling device according to claim 3, characterized in that: The liquid sampler also includes a gland arranged above the limiting ring, and a plurality of filter holes are formed on the gland; the filter adapter is connected with the filter holes through the inlet of the collector.

5. The active and passive sampling device according to claim 4, characterized in that: The upper and lower ends of the liquid sampler sleeve are both provided with grooves, and O-rings are installed inside the grooves.

6. The active and passive sampling device according to any one of claims 1 to 5, characterized in that: The installation method of the collector and the coating bracket is: the coating bracket is a non-supporting PTFE coating bracket, and the collector is a built-in collector. The upper part of the built-in collector has an outer ring, which is fixed to the non-supporting PTFE coating bracket with screw holes by screws.

7. The active and passive sampling device according to any one of claims 1 to 5, characterized in that: The collector and the coating bracket are installed in the following manner: the coating bracket is a supporting PTFE coating bracket, and the collector is an independent collector, which is directly supported on a supporting plate of the supporting PTFE coating bracket.

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