A method and system for detecting pesticide residues in soil

Abstract

The invention relates to the technical field of soil pollution, and in particular to a method and system for detecting soil pesticide residues, comprising: determining a mixed solution ratio; drying to obtain a dry soil sample; performing air condensation on circulating air to obtain a first solution and a second solution; the mass of the soil sample remains unchanged, and whether there are pesticide residues is determined according to a volume change rate; if it is determined that there are no pesticide residues, it is determined that the drying is completed; using a mixed solution to extract the dry soil sample to obtain a third solution; mixing to obtain a detection solution, and detecting the pesticide residues in the detection solution; the invention dries the soil in a closed environment to obtain dry soil and humid air, and further condenses and dries the humid air, thereby dividing the pesticide residues into three parts, namely, in the dry soil, in the dry air, and in the condensed water, thereby avoiding the loss of the pesticide residues and increasing the accuracy of the pesticide detection process.

Description

Technical Field

[0001] The present invention relates to the technical field of soil pollution, and in particular to a method and system for detecting pesticide residues in soil. Background Art

[0002] Soil pesticide residue detection plays a vital role in ensuring food safety, protecting the ecological environment, and promoting sustainable agriculture. Through effective detection and management, the harmonious development of agriculture and the environment can be achieved, ensuring human health and ecological balance. In existing detection equipment, pre-treatment is performed before detection to collect soil samples and gases; however, in the process of treating the silt at the bottom of the river, the volatilization of water in the silt will also affect the detection value, but the existing detection equipment does not have a device for collecting water in the soil, and during the soil pesticide detection process, some pesticides will volatilize into the air, resulting in inaccurate detection results of soil pesticide residues. Summary of the invention

[0003] The purpose of the present invention is to provide a method and system for detecting soil pesticide residues, so as to solve the problem of inaccurate detection results of soil pesticide residues in the prior art.

[0004] In one aspect, the present invention provides a method for detecting pesticide residues in soil, comprising:

[0005] Determine the ratio of the mixed solution based on the soil application history;

[0006] The soil sample is placed in a closed drying chamber, and the soil sample is dried to obtain a dry soil sample;

[0007] During the drying process, the air in the closed drying chamber is circulated and the circulating air is condensed to obtain a first solution and a second solution;

[0008] During the drying process, the soil quality is tested periodically. When the quality of the soil sample remains unchanged, the volume change rate after the dry air is passed into the mixed solution is used to determine whether there are pesticide residues in the circulating air.

[0009] If it is determined that there is no pesticide residue in the circulating air, it is determined that the drying is completed;

[0010] Extracting the dried soil sample using the mixed solution to obtain a third solution;

[0011] The first solution, the second solution and the third solution are mixed to obtain a detection solution, and the pesticide residues in the detection solution are detected;

[0012] Wherein: the first solution is obtained by passing dried circulating air into a mixed solution, and the second solution is obtained by extracting condensed water through a solid phase extraction column and then eluting with a mixed solution.

[0013] As a preferred technical solution of the method for detecting soil pesticide residues, the step of circulating air in the closed drying chamber includes:

[0014] Extracting the air in the closed drying chamber from the air outlet;

[0015] Air condensation is performed on the extracted air;

[0016] The condensed dry air is passed into the mixed solution, and the condensed water is collected by a collecting device;

[0017] The dry air after passing through the mixed solution is transported back to the closed drying chamber to complete a complete air cycle.

[0018] As a preferred technical solution of the method for detecting pesticide residues in soil, the preparation of the second solution specifically includes the following steps:

[0019] During the drying process, the condensed water is collected by a collection device;

[0020] After determining that the drying is completed, activating the solid phase extraction column using the mixed solution;

[0021] introducing the condensed water into the solid phase extraction column until all the condensed water flows through the solid phase extraction column;

[0022] The pesticide on the solid phase extraction column is eluted with the mixed solution to obtain an eluate, which is recorded as the second solution.

[0023] As a preferred technical solution of the method for detecting pesticide residues in soil, passing the dry air into the mixed solution to obtain the first solution specifically includes:

[0024] placing the soil sample into the closed drying chamber;

[0025] Starting drying and turning on the air circulation;

[0026] After condensation, the circulating air is dried.

[0027] The dry air is continuously introduced into the mixed solution;

[0028] After it is determined that the drying is completed, the air circulation is continued and the volume change rate of the bubbles in the mixed solution from the bottom to the top is continuously detected, and whether there is any residual pesticide in the circulating air is determined according to the volume change rate;

[0029] After it is determined that there is no pesticide residue, the air circulation is stopped. At this time, the mixed solution into which the dry air is introduced is recorded as the first solution.

[0030] As a preferred technical solution for detecting pesticide residues in soil, whether there are pesticides remaining in the circulating air is determined based on the volume change rate, wherein:

[0031] If the volume change rate is greater than or equal to the change rate threshold, it is determined that there is no residual pesticide in the circulating air and the drying is completed;

[0032] If the volume change rate is less than the change rate threshold, it is determined that there are residual pesticides in the circulating air and the air circulation continues.

[0033] As a preferred technical solution for the method of detecting pesticide residues in soil, after it is determined that the drying is completed, the air circulation channel is closed.

[0034] In another aspect, the present invention provides a detection system for a method for detecting pesticide residues in soil, comprising:

[0035] A drying module, comprising a closed drying chamber, a drying device, a circulating air inlet and a circulating air outlet;

[0036] An air circulation module, which is connected to the drying module and includes an air pump and a one-way exhaust port for providing power for air circulation in the closed drying chamber;

[0037] a condensation module, which is connected to the air circulation module and the drying module respectively, and is used to condense the circulating air;

[0038] A recovery module, which is connected to the condensation module and the drying module respectively, and includes a first recovery unit for recovering the pesticide in the dry air and a second recovery unit for recovering the pesticide in the condensed water;

[0039] The detection module is connected to the drying module and the recovery module respectively, and includes a quality detection unit arranged in the drying module for detecting the soil quality during the drying process, an image acquisition unit arranged in the recovery module for collecting the bubble volume, and a pesticide residue detection unit for detecting pesticides.

[0040] As a preferred technical solution for the detection system of soil pesticide residues, the image acquisition unit is used to calculate the volume of the bubble when it appears at the bottom of the gas collecting bottle and the volume just before it breaks on the surface of the mixed solution based on the collected image. The calculation formula of the volume change rate is configured as: volume change rate = (volume just before the bubble breaks - volume when the bubble appears) / volume when it is just formed.

[0041] As a preferred technical solution of the soil pesticide residue detection system, the first recovery unit includes a dry air inlet, a gas collecting bottle containing a mixed solution, and a dry air outlet;

[0042] The second recovery unit includes a collecting device, a water pump and a solid phase extraction column.

[0043] As a preferred technical solution for the soil pesticide residue detection system, before drying begins, the air pump is also used to extract the air in the closed drying chamber and exhaust it to the outside through the one-way exhaust port. After the air pressure in the closed drying chamber reaches the air pressure threshold, the air pump stops and closes the one-way exhaust port.

[0044] Compared with the prior art, the beneficial effect of the present invention lies in that the present invention dries the soil in a closed environment to obtain dry soil and moist air, and further condenses and dries the moist air, thereby dividing the pesticide residues into three parts, namely, in the dry soil, in the dry air, and in the condensed water. The same mixed solution allows the first solution, the second solution, and the third solution obtained after drying to be directly mixed, thereby detecting multiple pesticide concentrations at one time, and during the detection process, the loss of pesticide residues is avoided, thereby increasing the accuracy of the pesticide detection process. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A flow chart of the steps of a method for detecting pesticide residues in soil provided by an embodiment of the present invention;

[0046] Figure 2 A flowchart of the steps of performing air circulation on the closed drying chamber according to an embodiment of the present invention;

[0047] Figure 3 This is a flow chart of the steps of passing the dry air into the mixed solution to obtain the first solution according to an embodiment of the present invention;

[0048] Figure 4 The structure diagram of the soil pesticide residue detection system according to an embodiment of the present invention is shown in FIG. DETAILED DESCRIPTION

[0049] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0050] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0051] See also Figure 1 As shown, it is a flow chart of the steps of a method for detecting pesticide residues in soil provided by an embodiment of the present invention, comprising the steps of:

[0052] Determine the proportion of the mixed solution based on the soil application history;

[0053] The soil sample is placed in a closed drying chamber, and the soil sample is dried to obtain a dry soil sample;

[0054] During the drying process, the air in the closed drying chamber is circulated and the circulating air is condensed to obtain a first solution and a second solution;

[0055] During the drying process, the soil quality is tested periodically. When the quality of the soil sample remains unchanged, the volume change rate of the dry air passing into the mixed solution is used to determine whether there are pesticide residues in the circulating air.

[0056] If it is determined that there is no pesticide residue in the circulating air, it is determined that the drying is completed;

[0057] Extracting the dried soil sample using the mixed solution to obtain a third solution;

[0058] The first solution, the second solution and the third solution are mixed to obtain a detection solution, and the pesticide residues in the detection solution are detected;

[0059] Wherein: the first solution is obtained by passing dried circulating air into a mixed solution, and the second solution is obtained by extracting condensed water through a solid phase extraction column and then eluting with a mixed solution.

[0060] Specifically, the ratio of the mixed solution is determined according to the soil application history:

[0061] Determine the type of pesticide based on the soil pesticide application history;

[0062] After the type of organic solution of the mixed solution is determined according to the type of pesticide, several organic solutions are mixed. Each organic solution in the mixed solution formula should meet the following requirements: they can be mutually soluble and can dissolve the determined type of pesticide, and the mixing ratio of each organic solution must meet the concentration of each pesticide within the effective range of detection. Among them: the type of pesticide, suitable organic solution, the mutual solubility between organic solutions, and the overall concentration after mixing that can ensure the concentration of the pesticide is within the effective range of detection can all be directly obtained through limited experiments or big data, and will not be repeated here.

[0063] In detail, in the above embodiment, a suitable mixed solution is configured according to the pesticide application history, so that multiple pesticide residues can be detected at one time, saving detection time; by drying the soil in a closed environment, dry soil and humid air are obtained, and the humid air is further condensed and dried, the pesticide residues are divided into three parts, namely, in the dry soil, in the dry air, and in the condensed water. The same mixed solution allows the first solution, the second solution, and the third solution obtained after the drying to be directly mixed, so that multiple pesticide concentrations can be detected at one time, and during the detection process, the loss of pesticide residues is avoided, thereby increasing the accuracy of the pesticide detection process.

[0064] See also Figure 2 As shown, it is a flow chart of the steps of performing air circulation in the closed drying chamber according to an embodiment of the present invention, including:

[0065] Extracting the air in the closed drying chamber from the air outlet;

[0066] Air condensation is performed on the extracted air;

[0067] The condensed dry air is passed into the mixed solution, and the condensed water is collected by a collecting device;

[0068] The dry air after passing through the mixed solution is transported back to the closed drying chamber to complete a complete air cycle.

[0069] In detail, the air in the closed drying chamber is continuously condensed and introduced into the mixed solution through air circulation, so that the volatile pesticide residues in the closed drying chamber can be extracted.

[0070] Specifically, the second solution is prepared by extracting condensed water through a solid phase extraction column and further comprises the following steps:

[0071] During the drying process, the condensed water is collected by a collection device;

[0072] After determining that the drying is completed, activating the solid phase extraction column using the mixed solution;

[0073] introducing the condensed water into the solid phase extraction column until all the condensed water flows through the solid phase extraction column;

[0074] The pesticide on the solid phase extraction column is eluted with the mixed solution to obtain an eluate, which is recorded as the second solution.

[0075] See also Figure 3 As shown, it is a flow chart of the steps of passing the dry air into the mixed solution to obtain the first solution according to an embodiment of the present invention, including the steps of:

[0076] placing the soil sample into the closed drying chamber;

[0077] Starting drying and turning on the air circulation;

[0078] After condensation, the circulating air is dried.

[0079] The dry air is continuously introduced into the mixed solution;

[0080] After it is determined that the drying is completed, the air circulation continues and the volume change rate of the bubbles in the mixed solution from the bottom to the top is continuously detected, and whether there is residual pesticide in the circulating air is determined according to the volume change rate;

[0081] After it is determined that there is no pesticide residue, the air circulation is stopped. At this time, the mixed solution introduced by the dry air is the first solution.

[0082] Specifically, whether there is residual pesticide in the circulating air is determined based on the volume change rate, where:

[0083] If the volume change rate is greater than or equal to the change rate threshold, it is determined that there is no residual pesticide in the circulating air and the drying is completed;

[0084] If the volume change rate is less than the change rate threshold, it is determined that there are residual pesticides in the circulating air and the air circulation continues.

[0085] In detail, if there is no pesticide residue in the air, the molecular weight of the air in the bubble is unchanged at the moment the bubble bursts from the bottom to the top of the mixed solution, and the selection of the change rate threshold can be calculated through a finite number of experiments or formulas such as the ideal gas state equation. On the one hand, if there is pesticide in the air, it will dissolve into the mixed solution, the molecular weight in the bubble will decrease, and the volume of the bubble before splitting will change less than the volume of air without pesticides. If a finite number of experiments are used to determine the change rate threshold, the average value of the valid experimental data is taken. The calculation process or the experimental process belongs to the prior art. The embodiment of the present invention does not limit the specific selection method, which will not be repeated here.

[0086] Specifically, after the air circulation is finished, the air circulation channel is closed.

[0087] See also Figure 4 As shown, it is a structural block diagram of a soil pesticide residue detection system according to an embodiment of the present invention, comprising:

[0088] A drying module, comprising: a closed drying chamber, a drying device, a circulating air inlet and a circulating air outlet;

[0089] An air circulation module, which is connected to the drying module and includes an air pump and a one-way exhaust port for providing power for air circulation in the closed drying chamber;

[0090] A condensation module, connected to the air circulation module and the drying module, for condensing the circulating air;

[0091] A recovery module, which is connected to the condensation module and the drying module, and includes: a first recovery unit for recovering pesticides in dry air and a second recovery unit for recovering pesticides in condensed water;

[0092] The detection module is connected to the drying module and the recovery module respectively, and includes: a quality detection unit arranged in the drying module for detecting the quality of the soil during the drying process, an image acquisition unit arranged in the recovery module for collecting the volume of bubbles, and a pesticide residue detection unit for detecting pesticides.

[0093] Wherein: the detection method of the pesticide residue detection unit can be selected as gas chromatography or liquid chromatography for detection.

[0094] Specifically, the image acquisition unit is used to calculate the volume of the bubble when it is just formed at the bottom of the gas collecting bottle and the volume of the bubble just before it bursts on the surface of the mixed solution based on the collected image. The calculation formula of the volume change rate is configured as: volume change rate = (volume just before the bubble bursts - volume when the bubble appears) / volume when the bubble appears.

[0095] Specifically, the first recovery unit and the second recovery unit include:

[0096] The first recovery unit: a dry air inlet, a gas collecting bottle containing a mixed solution, and a dry air outlet;

[0097] The second recovery unit: condensed water collection device, water pump and solid phase extraction column.

[0098] Specifically, before drying begins, the air pump draws out the air in the closed drying chamber and opens the one-way exhaust port to exhaust the air outwards. After the air pressure in the closed drying chamber reaches the air pressure threshold, the air pump stops and closes the one-way exhaust port.

[0099] In detail, the determination of the air pressure threshold needs to be based on the maximum pressure that the closed drying chamber can withstand. After determining the maximum pressure, the maximum value of the air pressure before drying can be obtained while ensuring the safety of the closed drying chamber based on the ideal gas state equation or experiments. The calculation formula or experimental process are all existing technologies and will not be elaborated here.

[0100] In detail, in the above embodiment, part of the air in the closed drying chamber is extracted before drying begins, so that after the air expands due to heat during the drying process, it will not cause a large pressure on the closed drying chamber, thereby ensuring safety during the drying process.

[0101] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. 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 claims of the present invention.

Claims

1. A method for detecting pesticide residues in soil, characterized in that: include: Determine the proportion of the mixed solution based on the history of pesticide application; The soil sample is placed in a closed drying chamber, and the soil sample is dried to obtain a dry soil sample; During the drying process, the air in the closed drying chamber is circulated and the circulating air is condensed; The condensed dry air is passed into the mixed solution, and the condensed water is collected by a collecting device to obtain a first solution and a second solution; During the drying process, the soil quality is tested periodically. When the quality of the soil sample remains unchanged, the volume change rate after the dry air is passed into the mixed solution is used to determine whether there are pesticide residues in the circulating air. If it is determined that there is no pesticide residue in the circulating air, it is determined that the drying is completed; Extracting the dried soil sample using the mixed solution to obtain a third solution; The first solution, the second solution and the third solution are mixed to obtain a detection solution, and the pesticide residues in the detection solution are detected; Wherein: the first solution is obtained by passing the dry air into the mixed solution, and the second solution is obtained by extracting condensed water through a solid phase extraction column and eluting with the mixed solution.

2. The method for detecting soil pesticide residues according to claim 1, characterized in that: The step of circulating air in the closed drying chamber comprises: Extracting the air in the closed drying chamber from the air outlet; Air condensation is performed on the extracted air; The condensed dry air is passed into the mixed solution, and the condensed water is collected by a collecting device; The dry air after passing through the mixed solution is transported back to the closed drying chamber to complete a complete air cycle.

3. The method for detecting soil pesticide residues according to claim 2, characterized in that: The preparation of the second solution specifically comprises the following steps: During the drying process, the condensed water is collected by a collection device; After determining that the drying is completed, activating the solid phase extraction column using the mixed solution; introducing the condensed water into the solid phase extraction column until all the condensed water flows through the solid phase extraction column; The pesticide on the solid phase extraction column is eluted with the mixed solution to obtain an eluate, which is recorded as the second solution.

4. The method for detecting soil pesticide residues according to claim 1, characterized in that: Passing the dry air into the mixed solution to obtain the first solution specifically comprises: placing the soil sample into the closed drying chamber; Start drying and start the air circulation; After condensation, the circulating air is dried. The dry air is continuously introduced into the mixed solution; After it is determined that the drying is completed, the air circulation is continued and the volume change rate of the bubbles in the mixed solution from the bottom to the top is continuously detected, and whether there is any residual pesticide in the circulating air is determined according to the volume change rate; After it is determined that there is no pesticide residue, the air circulation is stopped. At this time, the mixed solution into which the dry air is introduced is recorded as the first solution.

5. The method for detecting soil pesticide residues according to claim 4, characterized in that: Whether there is residual pesticide in the circulating air is determined based on the volume change rate, where: If the volume change rate is greater than or equal to the change rate threshold, it is determined that there is no residual pesticide in the circulating air and the drying is completed; If the volume change rate is less than the change rate threshold, it is determined that there are residual pesticides in the circulating air and the air circulation continues.

6. The method for detecting soil pesticide residues according to claim 4, characterized in that: After it is determined that the drying is completed, the air circulation channel is closed.

7. A detection system using the method for detecting soil pesticide residues according to any one of claims 1 to 6, characterized in that: include: A drying module, comprising a closed drying chamber, a drying device, a circulating air inlet and a circulating air outlet; An air circulation module, which is connected to the drying module and includes an air pump and a one-way exhaust port for providing power for air circulation in the closed drying chamber; a condensation module, which is connected to the air circulation module and the drying module respectively, and is used to condense the circulating air; A recovery module, which is connected to the condensation module and the drying module respectively, and includes a first recovery unit for recovering the pesticide in the dry air and a second recovery unit for recovering the pesticide in the condensed water; The detection module is connected to the drying module and the recovery module respectively, and includes a quality detection unit arranged in the drying module for detecting the soil quality during the drying process, an image acquisition unit arranged in the recovery module for collecting the bubble volume, and a pesticide residue detection unit for detecting pesticides.

8. The detection system of the method for detecting pesticide residues in soil according to claim 7, characterized in that: The image acquisition unit is used to calculate the volume of the bubble when it appears at the bottom of the gas collecting bottle and the volume just before it breaks on the surface of the mixed solution based on the collected images. The calculation formula for the volume change rate is configured as: volume change rate = (volume just before the bubble breaks - volume when the bubble appears) / volume when it is just formed.

9. The detection system of the method for detecting pesticide residues in soil according to claim 8, characterized in that: The first recovery unit comprises a dry air inlet, a gas collecting bottle containing a mixed solution, and a dry air outlet; The second recovery unit includes a collecting device, a water pump and a solid phase extraction column.

10. The detection system of the method for detecting pesticide residues in soil according to claim 9, characterized in that: Before drying begins, the air pump is also used to extract the air in the closed drying chamber and exhaust it outward through the one-way exhaust port. After the air pressure in the closed drying chamber reaches the air pressure threshold, the air pump stops and closes the one-way exhaust port.

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