A filtering extraction device for liquid sample pesticide detection

Abstract

The utility model discloses a kind of filtering extraction devices for liquid sample pesticide detection, it is related to pesticide residue detection technical field.The device includes filter tank, switch valve, communication pipeline and separating funnel, filter tank is connected with separating funnel by communication pipeline sealing and is controlled by switch valve to open and close.Filter tank top is equipped with sample liquid inlet and exhaust port with sealing plug cover, inside top is equipped with conical filter port and detachable conical filter paper, in tank is arranged with helical openwork blade stirring assembly, outside is wound with flexible heating wire and is equipped with temperature sensor, and outer package heat insulation layer;Separating funnel bottom is equipped with liquid outlet pipe A with two-way piston, near bottom is connected with inclined flow guide pipe and liquid outlet pipe B.The device realizes the integration of filtering and extraction, continuous processing, simultaneously accurately controls extraction condition, reduces artificial error, significantly improves the efficiency and quality of liquid sample pesticide detection pretreatment.

Description

Technical Field

[0001] This utility model relates to the field of pesticide residue detection technology, and more specifically, to a filtration and extraction device for pesticide detection in liquid samples. Background Technology

[0002] Pesticide residue detection is an important part of ensuring food and environmental safety, and the pretreatment (filtration and extraction) of liquid samples is a key step in the pesticide residue detection process. Its treatment effect directly affects the accuracy and reliability of subsequent test results.

[0003] In pesticide testing, filtering and extraction of liquid samples are crucial pretreatment steps to remove impurities and separate target pesticide components, ensuring accurate subsequent detection. Currently, the filtration and extraction of liquid samples are typically performed using a separatory funnel, but this method has significant shortcomings:

[0004] 1. Low precision in extraction condition control: The separatory funnel has a simple structure and lacks precise temperature control and stirring adjustment functions. Due to the differences in the physicochemical properties (such as boiling point, solubility, etc.) of different pesticides, specific extraction temperatures and stirring intensities are required to achieve efficient extraction. However, existing devices cannot meet this requirement, resulting in low extraction efficiency, large fluctuations in the recovery rate of target pesticide components, and affecting the stability of detection.

[0005] 2. Cumbersome operation and high risk of error: Filtration and extraction require two different devices to operate in steps, which is complicated. This not only prolongs the sample processing time, but also easily introduces human error during the equipment switching process (such as loss or contamination during sample transfer), making it difficult to meet the needs of rapid processing of batch samples.

[0006] Therefore, there is an urgent need for an integrated and precise device to solve the problems of low extraction efficiency, poor condition control, and inconvenient operation in existing technologies, and to improve the efficiency and quality of pretreatment for pesticide detection of liquid samples. Utility Model Content

[0007] To address the shortcomings of existing devices, the purpose of this invention is to provide a filtration and extraction device for pesticide detection in liquid samples. This device solves the problems of low filtration and extraction efficiency, inaccurate control of extraction conditions, and inconvenient operation of existing devices. It achieves integrated and continuous processing of filtration and extraction, while precisely controlling extraction conditions, reducing human error, and significantly improving the efficiency and quality of pretreatment for pesticide detection in liquid samples.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0009] A filtration and extraction device for detecting pesticides in liquid samples includes a filter tank, a switching valve, a connecting pipe, and a separating funnel; the filter tank and the separating funnel are connected by a connecting pipe, and the connecting pipe is equipped with a switching valve.

[0010] The filter tank is provided with a sample inlet at the top, and a sealing plug is provided inside the sample inlet. The top of the sample inlet is provided with an exhaust port that communicates with the inside of the filter tank. The filter tank is provided with a filter port at the top inside, and a filter layer is provided inside the filter port. The filter tank is provided with a stirring assembly inside. The filter tank is also provided with a heating module on the outside.

[0011] The separatory funnel is provided with a liquid outlet pipe A at the bottom, and a two-way piston is provided on the liquid outlet pipe A; an inclined guide pipe is connected to the separatory funnel near the bottom, and a vertical liquid outlet pipe B is connected to the bottom of the guide pipe, and a rubber stopper is provided inside the guide pipe.

[0012] Furthermore, the stirring assembly consists of a motor and a stirrer. The motor is located on one side of the filter tank, and the stirrer is inclinedly located inside the filter tank, with the upper end of the stirrer connected to the output end of the motor.

[0013] Furthermore, the stirrer includes a stirring shaft and stirring blades, the stirring blades are spirally distributed at the lower end of the outer side of the stirring shaft, and the surface of the stirring blades is provided with several hollow holes.

[0014] Furthermore, the heating module includes a flexible heating wire wrapped around the outside of the filter canister, and a temperature sensor that works in conjunction with the flexible heating wire is provided at the bottom of the filter canister, with the sensing end of the temperature sensor extending into the interior of the filter canister.

[0015] Furthermore, the temperature sensor is electrically connected to an external controller, which is also electrically connected to the flexible heating wire. The external controller can adjust the heating power of the flexible heating wire based on the temperature data fed back by the temperature sensor, with a temperature control accuracy of ±0.5℃.

[0016] Furthermore, the filter canister is covered with a heat insulation layer, and the flexible heating wire is located between the heat insulation layer and the outer wall of the filter canister. The thickness of the heat insulation layer is 1-2 cm.

[0017] Furthermore, the filter layer is filter paper, and the filter opening is a conical structure. The filter paper is folded into a conical structure that fits the filter opening and is detachably snapped into the filter opening.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. This device directly connects the filter tank and the separatory funnel through a connecting pipeline. After impurities are filtered in the filter tank, the sample can be directly controlled by the switch valve to flow into the separatory funnel for extraction. There is no need to transfer the sample to a separate device, which reduces at least two sample transfer steps, reduces processing time, and avoids sample loss and external contamination risks during the transfer process, thus improving the stability of sample processing.

[0020] 2. The stirring component of this device adopts a spiral blade + hollow hole design, and with an adjustable speed motor, the stirring intensity can be adjusted according to the sample viscosity and the type of extractant to ensure that the sample and extractant are fully mixed. The mixing uniformity is improved by more than 40% compared with traditional manual shaking. The heating and temperature control components can achieve precise temperature control from room temperature to 60°C, which can meet the optimal extraction temperature requirements of different pesticides.

[0021] 3. The filter layer of this device uses removable conical filter paper. When replacing it, simply open the sealing plug to remove the old filter paper and install the new one. The operation time is no more than 30 seconds. The heat insulation layer keeps the outer wall temperature of the filter tank at room temperature, preventing burns to the operator. The liquid outlet pipe A and liquid outlet pipe B control the discharge of the upper and lower liquid layers respectively. The operation logic is clear, and even novice operators can quickly master it, lowering the operating threshold. In addition, all components of the device are made of corrosion-resistant materials and are compatible with a variety of commonly used extraction agents (such as acetonitrile, dichloromethane, and ethyl acetate), making it widely applicable.

[0022] Of course, any product implementing this utility model does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0025] Figure 2 This is a front view of the present invention.

[0026] Figure 3 This is a schematic diagram of the filter tank in this utility model.

[0027] Figure 4 This is a cross-sectional view of the filter tank in this utility model.

[0028] Figure 5 This is a schematic diagram of the separation funnel in this utility model.

[0029] Figure 6 This is a partial cross-sectional view of the liquid outlet pipe B in this utility model.

[0030] In the diagram: 1. Filter tank; 2. Switch valve; 3. Connecting pipe; 4. Separating funnel; 5. Outlet pipe A; 6. Sample inlet; 7. Sealing cap; 8. Exhaust port; 9. Motor; 10. Insulation layer; 11. Filter layer; 12. Filter port; 13. Stirrer; 14. Temperature sensor; 15. Flexible heating wire; 16. Two-way piston; 17. Outlet pipe B; 18. Guide pipe; 19. Rubber stopper. Detailed Implementation

[0031] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0032] Example 1:

[0033] like Figures 1 to 6 As shown, a filtration and extraction device for detecting pesticides in liquid samples includes a filter tank 1, a switch valve 2, a connecting pipe 3, and a separating funnel 4. The filter tank 1 is made of transparent glass and is sealed to the separating funnel 4 through the connecting pipe 3. The switch valve 2 is connected in series in the middle of the connecting pipe 3 to control the flow of fluid between the filter tank 1 and the separating funnel 4. Both ends of the connecting pipe 3 are integrally connected to the bottom of the filter tank 1 and the top of the separating funnel 4, respectively, to ensure no leakage during fluid transmission.

[0034] A circular sample inlet 6 is provided at the center of the top of the filter tank 1. The inner diameter of the sample inlet 6 is 3-5cm. It is fitted with a rubber sealing cap 7. The outer diameter of the sealing cap 7 is interference-fitted with the inner diameter of the sample inlet 6, so that it can be tightly embedded in the sample inlet 6 to prevent sample leakage or external air and impurities from entering the tank.

[0035] The top of the sample inlet 6 is integrally formed with a cylindrical vent 8. The inner diameter of the vent 8 is 0.5-1cm. One end of the vent 8 is connected to the internal space of the filter tank 1, and the other end extends to the outside of the filter tank 1. It is used to expel the air in the tank during sample injection or stirring to avoid excessive pressure in the tank from hindering sample flow or causing the sealing cap 7 to pop out.

[0036] A filter port 12 is provided at the top of the filter tank 1, directly below the sample inlet 6. The filter port 12 has a tapered structure that is wider at the top and narrower at the bottom, with a cone angle of 60-90°. The filter port 12 has a removable filter layer 11 inside, which is convenient for replacement and cleaning.

[0037] The filter layer 11 uses quantitative filter paper, which is pre-folded into a conical structure that matches the cone angle of the filter port 12 and is detachably clipped into the filter port 12. The conical structure design can increase the contact area between the filter paper and the sample, improve the filtration speed, and facilitate the concentrated retention of impurities on the surface of the filter paper, reducing clogging.

[0038] A motor 9 is fixedly installed on one side of the outer wall of the filter tank 1 via a special interface. The motor 9 is a miniature DC geared motor. The stirrer 13 includes a stirring shaft and stirring blades. The upper end of the stirring shaft is connected to the output shaft of the motor 9 via a coupling. The lower end of the stirring shaft extends into the filter tank 1 at an angle of 30-45° relative to the vertical direction, which can expand the stirring range and avoid the formation of dead zones at the bottom of the tank. The stirring blades are made of stainless steel and are spirally welded to the outer side of the lower end of the stirring shaft. There are two blades, and the surface of the blades is evenly provided with several perforations with a diameter of 1-2 mm. The perforations can reduce the resistance to the sample during stirring, reduce sample splashing, and promote the convection mixing of the sample and the extractant, thereby improving the mixing uniformity.

[0039] A flexible heating wire 15 is wound around the outer wall of the filter canister 1. The flexible heating wire 15 is made of nickel-chromium alloy and has a winding density of 2-3 turns per centimeter. The heating wire is tightly attached to the outer wall of the filter canister 1 to ensure efficient heat transfer. A temperature sensor 14 is installed at the bottom of the filter canister 1 by threads. The temperature sensor 14 is a platinum resistance temperature sensor. Its probe extends into the canister through the bottom wall of the filter canister 1. The surface of the probe is covered with a polytetrafluoroethylene protective layer to prevent it from being corroded by the sample.

[0040] Temperature sensor 14 is electrically connected to external controller via a PLC controller or microcontroller through wires. External controller is also electrically connected to flexible heating wire 15 through wires. External controller can receive real-time temperature data fed back by temperature sensor 14 and automatically adjust the heating power of flexible heating wire 15 according to the preset temperature threshold adjustment range of room temperature to 60℃, so as to achieve precise control of sample temperature in filter tank 1. Temperature control accuracy can reach ±0.5℃.

[0041] The outer side of the filter tank 1 is also covered with a heat insulation layer 10. The heat insulation layer 10 is made of rock wool or polyurethane foam and is 1-2cm thick. The flexible heating wire 15 is completely wrapped between the heat insulation layer 10 and the outer wall of the filter tank 1, which can effectively reduce heat loss, improve heating efficiency, and prevent operators from touching the heating wire and getting burned.

[0042] Separating funnel 4 is made of transparent glass and has a volume of 250-500mL. A liquid outlet tube A5 is integrally formed at the center of its bottom. Two pistons 16 are connected in series on the liquid outlet tube A5. The opening and closing of the liquid outlet tube A5 can be controlled by rotating the piston core. It is used to discharge the lower liquid after separation in the separating funnel 4, which is usually the extractant phase.

[0043] A guide tube 18 is integrally formed at an angle on the lower side wall of the separatory funnel 4, 1-2 cm from the bottom. The inner diameter of the guide tube 18 is the same as that of the outlet tube A5. The guide tube 18 is connected to the internal space of the separatory funnel 4. The angle of inclination of the guide tube 18 is 30-45° relative to the horizontal direction to facilitate the smooth flow of the upper liquid. An outlet tube B17 is integrally formed at the middle of the bottom of the free end of the guide tube 18. The inner diameter of the outlet tube B17 is the same as that of the guide tube 18. A rubber stopper 19 is fitted inside the outer end of the guide tube 18. The outer diameter of the rubber stopper 19 is interference-fitted with the inner diameter of the guide tube 18. The flow of the guide tube 18 can be controlled by inserting and removing the rubber stopper 19. This is used to discharge the upper liquid after stratification in the separatory funnel 4, which is usually the aqueous phase of the sample.

[0044] Example 2:

[0045] This embodiment uses "pretreatment for detecting organophosphorus pesticide residues in fruit and vegetable washing liquid" as an example to illustrate the steps of using this device:

[0046] 1. Sample preparation: Take 100mL of fruit and vegetable washing liquid sample, add 20mL of acetonitrile extractant, mix well, and use it as the sample to be processed.

[0047] 2. Filtration operation: Open the sealing plug 7 on the top of the filter tank 1, and insert the folded conical filter paper into the filter port 12, ensuring that the filter paper is tightly attached to the inner wall of the filter port 12; slowly pour the sample to be processed into the sample inlet 6. After the sample is filtered by the conical filter paper, the impurities are trapped on the filter paper, and the filtrate flows into the bottom of the filter tank 1; tighten the sealing plug 7, and the gas in the tank is discharged through the exhaust port 8 to avoid obstructing the sample flow.

[0048] 3. Stirring and heating extraction: The heating temperature is set to 35℃ by the external controller, and the heating function is started. The flexible heating wire 15 starts heating, and the temperature sensor 14 monitors the temperature inside the tank in real time. When the temperature reaches 35℃, the controller automatically adjusts the heating power to maintain a stable temperature. At the same time, the motor 9 is started and the speed is set to 200r / min. The stirrer 13 starts to rotate and stirs the mixture of sample and extractant in the tank for 5 minutes to ensure that the target pesticide components are fully dissolved in acetonitrile.

[0049] 4. Separation Operation: After stirring, turn off motor 9 and heating function, open switch valve 2, and the mixture in filter tank 1 flows into separatory funnel 4 through connecting pipe 3; after all the mixture has been transferred, close switch valve 2 and let the mixture in separatory funnel 4 stand for 10 minutes to allow the mixture to separate into two layers: the upper layer is the aqueous phase sample, and the lower layer is the acetonitrile phase containing the target pesticide; if it is necessary to collect the lower acetonitrile phase to be tested, slowly rotate the two-way stopcock 16 to open the outlet pipe A5, and the lower liquid flows out from the outlet pipe A5 and is collected into the sample bottle, so that the liquid surface is located in the area between the two-way stopcock 16 and the interface of the guide pipe 18. After collection is completed, close the two-way stopcock 16; then drain the upper aqueous phase, pull out the rubber stopper 19 in the guide pipe 18, and the upper liquid flows out from the outlet pipe B17 through the guide pipe 18 and is collected into the waste liquid bucket. After draining, put the rubber stopper 19 back in; finally, open the two-way stopcock 16 again to drain the remaining liquid on the liquid surface through the outlet pipe A5.

[0050] 5. Device Cleaning and Maintenance: After the test is completed, open the sealing plug 7, remove the waste filter paper from the filter port 12 and discard it; inject 200mL of clean water into the sample inlet 6, and at the same time start the motor 9 to drive the stirrer 13 to rotate. After a certain period of time, open the switch valve 2, and the clean water flows into the separatory funnel 4 and is discharged through the outlet pipe A5 and outlet pipe B17 respectively. Clean the filter tank 1, the connecting pipe 3 and the separatory funnel 4; after cleaning, dry the moisture inside the device to ensure normal use next time.

[0051] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating this utility model, and are not intended to limit the implementation of this utility model. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. Any obvious variations or modifications derived from the technical solutions of this utility model are still within the protection scope of this utility model.

Claims

1. A filtration extraction device for liquid sample pesticide detection, characterized in that, It includes a filter tank (1), a switch valve (2), a connecting pipe (3) and a separating funnel (4); the filter tank (1) and the separating funnel (4) are connected by the connecting pipe (3), and the connecting pipe (3) is equipped with a switch valve (2). The filter tank (1) is provided with a sample inlet (6) at the top, and a sealing plug (7) is provided inside the sample inlet (6). The top of the sample inlet (6) is provided with an exhaust port (8) that communicates with the inside of the filter tank (1). The filter tank (1) is provided with a filter port (12) at the top inside, and a filter layer (11) is provided inside the filter port (12). The filter tank (1) is provided with a stirring assembly inside. The filter tank (1) is also provided with a heating module on the outside. The bottom of the separating funnel (4) is provided with a liquid outlet pipe A (5), and the liquid outlet pipe A (5) is provided with two pistons (16); an inclined guide pipe (18) is connected to the bottom of the separating funnel (4), and a vertical liquid outlet pipe B (17) is connected to the bottom of the guide pipe (18), and a rubber stopper (19) is provided inside the guide pipe (18).

2. The filter extraction device for liquid sample pesticide detection according to claim 1, characterized in that: The stirring assembly consists of a motor (9) and a stirrer (13). The motor (9) is located on one side of the filter tank (1), and the stirrer (13) is inclined inside the filter tank (1). The upper end of the stirrer (13) is connected to the output end of the motor (9).

3. The filtration and extraction device for pesticide detection in liquid samples according to claim 2, characterized in that: The stirrer (13) includes a stirring shaft and stirring blades. The stirring blades are spirally distributed at the lower end of the outer side of the stirring shaft, and the surface of the stirring blades is provided with several hollow holes.

4. The filtration and extraction device for pesticide detection in liquid samples according to claim 1, characterized in that: The heating module includes a flexible heating wire (15), which is wound around the outside of the filter canister (1). The bottom of the filter canister (1) is provided with a temperature sensor (14) that works in conjunction with the flexible heating wire (15). The detection end of the temperature sensor (14) extends into the filter canister (1).

5. The filtration and extraction device for pesticide detection in liquid samples according to claim 4, characterized in that: The temperature sensor (14) is electrically connected to an external controller, which is also electrically connected to the flexible heating wire (15). The external controller can adjust the heating power of the flexible heating wire (15) based on the temperature data fed back by the temperature sensor (14), with a temperature control accuracy of ±0.5℃.

6. The filtration and extraction device for pesticide detection in liquid samples according to claim 4, characterized in that: The filter tank (1) is covered with a heat insulation layer (10) on the outside, and the flexible heating wire (15) is located between the heat insulation layer (10) and the outer wall of the filter tank (1). The thickness of the heat insulation layer (10) is 1-2 cm.

7. The filtration and extraction device for pesticide detection in liquid samples according to claim 1, characterized in that: The filter layer (11) is filter paper, and the filter port (12) is a conical structure. The filter paper is folded into a conical structure that fits the filter port (12) and can be detachably locked in the filter port (12).

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