A test paper for detecting omethoate and a preparation method and application thereof

Abstract

The application discloses a test strip for detecting omethoate as well as a preparation method and application thereof. The test strip comprises a test paper and a microporous reagent. The test paper comprises a reaction membrane, a sample absorption pad, a water absorption pad and a bottom plate. The reaction membrane is provided with a detection line coated with an omethoate hapten-carrier protein conjugate and a quality control line coated with a sheep anti-mouse antibody. The microporous reagent is freeze-dried with an omethoate monoclonal antibody-colloidal gold marker. The application further provides a method for detecting omethoate residues in fruits and vegetables by using the test strip. The test strip and the detection method have the advantages of simple operation, high sensitivity, fast detection speed, low cost and no limitation on detection equipment, and can realize on-site rapid detection of a large number of samples.

Description

TECHNICAL FIELD

[0001] The present application relates to the detection of oxime, and in particular to a colloidal gold test strip for detecting oxime, which is particularly suitable for detecting oxime residues in fruits and vegetables. BACKGROUND

[0002] Oxime is also known as oxime, which is a high-efficiency, high-toxicity, broad-spectrum insecticide and miticide with strong systemic, contact and stomach toxicity. It is used to control cotton aphids, cotton leafhoppers, rice planthoppers, rice leafhoppers, rice leafhoppers, citrus aphids, red spiders, citrus whiteflies, woodlice and red wax scales. Oxime belongs to high-toxicity organophosphorus pesticides, which has been prohibited for use in fruit and vegetable production in China, but some places still violate the regulations and oxime residues are often detected in water, soil, fruits and vegetables, which poses a serious threat to human health. GB 2763-2021 "National Food Safety Standard Maximum Residue Limits of Pesticides in Foods" stipulates that the maximum residue limit of oxime in vegetables and fruits is 0.02 mg / kg, so it is necessary to establish an efficient, sensitive and accurate method for detecting oxime in fruits and vegetables.

[0003] The methods reported so far for detecting oxime mainly include gas chromatography, gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry. These methods must be operated under laboratory conditions, the sample pretreatment is tedious and time-consuming, and expensive equipment is required, so the detection cost is high, the time is long, the operation is complex, and there is great limitation in practical application, which is difficult to meet the needs of rapid detection of a large number of samples and on-site samples. Therefore, the development of a simple and rapid colloidal gold test strip suitable for oxime residues in fruits and vegetables can meet the needs of on-site screening and monitoring of a large number of samples, and can better meet the detection needs of food supervision departments and others. SUMMARY

[0004] The present application aims to overcome the characteristics of the existing methods for detecting oxime, which have high dependence on equipment and cannot achieve rapid detection of a large number of samples, and to provide a test strip which is simple to operate, high in sensitivity, fast in detection speed, low in cost and not limited by detection equipment, as well as a preparation method and application thereof, so as to realize rapid detection of a large number of samples.

[0005] In order to achieve the purpose of the present application, the present application provides a test strip for detecting oxime, which comprises a test paper and a microporous reagent; the test paper comprises a bottom plate, a sample absorption pad, a reaction membrane and a water absorption pad, which are connected in sequence, the reaction membrane has a detection line coated with oxime hapten-carrier protein conjugate and a quality control line coated with sheep anti-mouse antibody; the microporous reagent has oxime monoclonal antibody-colloidal gold label freeze-dried thereon, and has a microporous plug.

[0006] The monoclonal antibody of omethoate is prepared by taking the omethoate hapten-carrier protein conjugate as an immunogen.

[0007] The omethoate hapten-carrier protein conjugate is obtained by coupling the omethoate hapten with a carrier protein, and the carrier protein is bovine serum albumin, ovalbumin, hemocyanin or human serum albumin.

[0008] The synthesis method of the omethoate hapten is as follows: 2.13 g of omethoate is dissolved in 80 mL of pyridine under nitrogen protection, 5 mL of a pyridine solution containing 1.08 g of acryloyl chloride is added dropwise, and reaction is carried out at 60 DEG C for 4 h; the reaction is stopped, pyridine is removed by rotary evaporation, and toluene is added for dissolution and rotary evaporation to remove pyridine; yellow oil is obtained, which is separated by elution with a silica gel column using a dichloromethane-methanol mixed solution with a volume ratio of 10:1 to obtain the omethoate hapten, and the molecular structural formula is as follows:

[0009]

[0010] The bottom plate is a PVC bottom plate or other hard non-water-absorbing material; the sample absorption pad is made of polyester fiber or glass fiber material; the water absorption pad is a water absorption filter paper; and the reaction membrane is a nitrocellulose membrane or an acetic acid cellulose membrane.

[0011] The application further provides a method for preparing the test strip, which comprises the following steps:

[0012] 1) preparing a micropore reagent with omethoate monoclonal antibody-gold label freeze-dried;

[0013] 2) preparing a reaction membrane with a detection line coated with omethoate hapten-carrier protein conjugate and a quality control line coated with sheep anti-mouse antibody;

[0014] 3) assembling the reaction membrane prepared in 2) with a sample absorption pad, a water absorption pad and a bottom plate into a test paper;

[0015] 4) assembling the micropore reagent with omethoate monoclonal antibody-gold label freeze-dried prepared in 1) and the test paper prepared in 3) into a test strip.

[0016] Specifically, the steps comprise:

[0017] 1) performing esterification reaction of omethoate and acryloyl chloride under catalysis of pyridine to prepare omethoate hapten;

[0018] 2) coupling the omethoate hapten with a carrier protein to prepare omethoate hapten-carrier protein conjugate;

[0019] 3) immunizing mice with the omethoate hapten-carrier protein conjugate, and obtaining hybridoma cell strains secreting omethoate monoclonal antibody by fusing mouse spleen cells and mouse myeloma cells and screening.

[0020] 4) Extracting mouse IgG to immunize healthy goat, and obtaining goat anti-mouse antibody;

[0021] 5) Coating oxpoconazole hapten-carrier protein conjugate and goat anti-mouse antibody on the test line (T) and control line (C) of the reaction membrane respectively;

[0022] 6) Preparing colloidal gold by reacting sodium citrate with chloroauric acid;

[0023] 7) Adding prepared oxpoconazole monoclonal antibody to prepared colloidal gold to obtain oxpoconazole monoclonal antibody-colloidal gold marker;

[0024] 8) Freeze-drying oxpoconazole monoclonal antibody-colloidal gold marker in micropore reagent, and then adding micropore reagent with micropore plug;

[0025] 9) Soaking sample absorption pad in 0.2 mol / L phosphate buffer solution containing 1% bovine serum albumin with pH of 7.2 for 2 h, and drying at 37℃ for 2 h for standby;

[0026] 10) Paste sample absorption pad, reaction membrane and water absorption pad on the bottom plate in sequence, and finally cut into small strips with width of 3.95 mm, add plastic box, and vacuum package;

[0027] 11) Assemble prepared micropore reagent and test paper into test paper strip, and store under condition of 2-8℃ for 12 months.

[0028] The application also provides a method for detecting oxpoconazole residue in fruits and vegetables by using the above test paper strip, which comprises the following steps:

[0029] (1) Sample pretreatment;

[0030] (2) Detecting by using the test paper strip;

[0031] (3) Analyzing detection result.

[0032] The oxpoconazole rapid detection test paper strip of the application adopts highly specific antigen-antibody reaction and immunochromatographic analysis technology, and freeze-dries oxpoconazole monoclonal antibody-colloidal gold marker in micropore reagent, so that oxpoconazole in the sample fully reacts with the marker to form drug-antibody-colloidal gold marker; then the marker is dropped into the hole of the test paper strip card, and the drug in the sample competes with oxpoconazole hapten-carrier protein conjugate on the test line of the reaction membrane to bind with oxpoconazole monoclonal antibody-colloidal gold marker in the flowing process, and whether the sample liquid contains oxpoconazole residue is determined according to the depth of the red band on the test line.

[0033] In the detection, the sample is dropped into the micro-pore reagent after treatment, and then added into the card hole of test strip after sufficient reaction. When the concentration of omethoate in the sample is below the detection limit or zero, the monoclonal antibody-gold label will be coupled with the omethoate hapten-carrier protein conjugate fixed on the reaction membrane in the chromatography process, and a red band will appear on the detection line (T) and the quality control line (C) respectively, and the color of T line is deeper than that of C line or consistent with that of C line; if the concentration of omethoate in the sample is equal to or higher than the detection limit, the monoclonal antibody-gold label will be coupled with omethoate, so that no red band will appear on the T line due to the competition reaction, or the color of T line is shallower than that of C line. As shown in the following table. Figure 5

[0034] Negative: when the quality control line (C) shows a red band, the detection line (T) also shows a red band, and the color of (T) line is close to or deeper than that of (C) line, it is judged as negative.

[0035] Positive: when the quality control line (C) shows a red band, and the detection line (T) does not show color or the color of (T) line is shallower than that of (C) line, it is judged as positive.

[0036] Invalid: when the quality control line (C) does not show a red band, whether the detection line (T) shows a red band or not, the test strip is judged as invalid.

[0037] The test strip of the present application has the advantages of high sensitivity, strong specificity, low cost, simple operation, short detection time, suitability for various units, simple storage, long shelf life. Among them, the high-specificity omethoate monoclonal antibody is used to ensure the reliability of the detection result; the gold-labeled antibody is freeze-dried in the micro-pore reagent, which can make the gold-labeled antibody fully contact with the sample liquid to be detected and fully react in the detection process, thereby reducing the error and increasing the reaction sensitivity of the whole system. The method for detecting omethoate by using the test strip of the present application is simple, rapid, intuitive, accurate, widely applicable, low in cost and easy to popularize. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 It is the synthesis diagram of omethoate hapten.

[0039] Figure 2 It is the nuclear magnetic resonance hydrogen spectrum diagram of omethoate hapten.

[0040] Figure 3 It is the schematic diagram of test strip cross-section structure.

[0041] Figure 4 It is the micro-pore reagent diagram.

[0042] Figure 5 It is the test strip detection result judgment diagram. DETAILED DESCRIPTION ​

[0043] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0044] Example 1: Preparation of a test strip for detecting omethoate

[0045] The preparation method of this test strip mainly includes the following steps:

[0046] 1) Microporous reagent for preparing lyophilized dimethoate monoclonal antibody-colloidal gold label;

[0047] 2) Prepare a reaction membrane with a detection line coated with an aerobic dimethoate hapten-carrier protein conjugate and a control line coated with goat anti-mouse anti-antibody;

[0048] 3) Assemble the reaction membrane prepared in 2) with the sample absorption pad, water absorption pad, and base plate to form a test paper;

[0049] 4) Assemble the lyophilized dimethoate monoclonal antibody-colloidal gold-labeled microwell reagent and test strip prepared in 1) and 3) into a test strip.

[0050] The following is a detailed step-by-step description:

[0051] 1. Synthesis of omethoate hapten (synthetic route is attached) Figure 1 )

[0052] Dissolve 2.13 g of omethoate in 80 mL of pyridine. Under nitrogen protection, add 5 mL of pyridine solution containing 1.08 g of acryloyl chloride. React at 60 °C for 4 h. Stop the reaction, remove pyridine by rotary evaporation, dissolve in toluene, and rotary evaporation to remove pyridine completely, giving a yellow oily substance. Load the substance onto a silica gel column and elute with a 10:1 (v / v) dichloromethane-methanol mixture to obtain 0.47 g of omethoate hapten.

[0053] Hydrogen nuclear magnetic resonance (HNMR) of the hapten 1 H-NMR) determination, results are as follows Figure 2 As shown: 1 1H NMR (500MHz, Chloroform-d): δ (ppm) 6.41–6.30 (m, OH), 6.07 (ddd, J = 16.3, 12.5, 2.4Hz, 1H), 3.84 (s, 1H), 3.79 (d, J = 10.8Hz, 2H), 3.09 (s, 1H). The peaks with chemical shifts δ 6.41–6.30 (m, OH) and 6.07 (ddd, J = 16.3, 12.5, 2.4Hz, 1H) in the 1H NMR spectrum are absorption peaks of the propenyl hydrogen, and the presence of these peaks confirms the correct hapten structure.

[0054] 2. Preparation of immunogens

[0055] Take 100 mg of bovine serum albumin (BSA), dissolve in 10 mL of phosphate buffer at pH 8.0, add 3.9 mg of dithiothreitol (DDT), and react at room temperature for 4 h to obtain solution A; take 6.8 mg of omethoate hapten, dissolve in 0.5 mL of N,N-dimethylformamide (DMF), and then add dropwise to solution A, react at room temperature for 6 h, and purify by dialysis in 0.02 mol / L PB buffer for 3 days, with liquid change 3 times per day, to obtain an omethoate hapten-BSA conjugate, which is the immunogen.

[0056] 3. Preparation of coating antigen

[0057] Take 100 mg of ovalbumin (OVA), dissolve in 10 mL of phosphate buffer at pH 8.0, add 1.7 mg of DDT, and react at room temperature for 4 h to obtain solution A; take 2.97 mg of omethoate hapten, dissolve in 0.5 mL of DMF, and then add dropwise to solution A, react at room temperature for 6 h, and purify by dialysis in 0.02 mol / L PB buffer for 3 days, with liquid change 3 times per day, to obtain an omethoate hapten-OVA conjugate, which is the coating antigen.

[0058] 4. Preparation of omethoate monoclonal antibody

[0059] (1) Animal immunization

[0060] The immunogen obtained in step 2 is injected into Balb / c mice, and the immunization dose is 150 μg per mouse, so that the mice produce antisera.

[0061] (2) Cell fusion and cloning

[0062] Take the spleen cells of the immunized Balb / c mice, and fuse them with SP2 / 0 myeloma cells at a ratio of 8:1 (quantity ratio), determine the cell supernatant by indirect competitive ELISA, and screen positive wells. The positive wells are cloned by limited dilution until a hybridoma cell strain stably secreting monoclonal antibody is obtained.

[0063] (3) Cell cryopreservation and recovery

[0064] The hybridoma cells are prepared into a cell suspension of 1×10 6 / mL with a cryopreservation solution, and stored in liquid nitrogen for long-term preservation. When recovered, the cryopreservation tube is taken out immediately and placed in a 37℃ water bath for rapid thawing. After centrifugation to remove the cryopreservation solution, the cells are transferred into a culture bottle for culture.

[0065] (4) Preparation and purification of monoclonal antibody

[0066] Incremental culture method: the hybridoma cells are placed in cell culture medium and cultured at 37℃, and the obtained culture solution is purified by octanoic acid-saturated ammonium sulfate method to obtain the monoclonal antibody, which is stored at -20℃.

[0067] The cell culture medium is RPMI1640 medium to which calf serum and sodium bicarbonate are added, so that the final concentration of the calf serum in the cell culture medium is 20% (mass fraction) and the final concentration of the sodium bicarbonate in the cell culture medium is 0.2% (mass fraction); the pH of the cell culture medium is 7.4.

[0068] 5. Preparation of goat anti-mouse antibody

[0069] The goat anti-mouse antibody is obtained by immunizing pathogen-free goats with mouse-derived antibodies as immunogens.

[0070] 6. Preparation of oxime gold monoclonal antibody-colloidal gold marker

[0071] (1) Preparation of colloidal gold

[0072] Dilute 1% chloroauric acid with double-distilled deionized water to 0.01% (mass fraction), take 100 mL and place in a conical flask, heat to boiling with a constant-temperature electromagnetic stirrer, add 1.5 mL of 1% trisodium citrate under continuous high temperature and continuous stirring, continue to stir at a uniform speed and heat until the solution is bright red, then stop, cool to room temperature, restore to the original volume with deionized water, and store at 4℃. The prepared colloidal gold is pure, bright, and free of precipitates and floating materials, and the color is wine red under sunlight.

[0073] (2) Preparation of oxime gold monoclonal antibody-colloidal gold marker

[0074] Under magnetic stirring, adjust the pH of the colloidal gold to 7.2 with 0.2 mol / L potassium carbonate solution, add the above-mentioned oxime gold monoclonal antibody to the colloidal gold solution at 5-50 μg of antibody per milliliter of colloidal gold solution, continue to stir and mix for 30 min; after standing for 10 min, add 10% BSA to make the final concentration of BSA in the colloidal gold solution 1%, and stand for 10 min. Centrifuge at 12000 r / min and 4℃ for 40 min, discard the supernatant, wash the precipitate with resuspension buffer twice, resuspend the precipitate with resuspension buffer with a volume of 1 / 10 of the initial colloidal gold volume, and store at 4℃.

[0075] Resuspension buffer: 0.02 mol / L phosphate buffer containing 0.1%-0.5% BSA (mass fraction) and 2%-4% sucrose (mass fraction), pH 7.2.

[0076] 7. Preparation of micropore reagent

[0077] Add 100 μL of omethoate monoclonal antibody-colloidal gold label to a microplate, place it in a freeze dryer, pre-freeze for 3 h at a cold trap temperature of -50 °C, and then vacuum dry for 15 h. The resulting lyophilized omethoate monoclonal antibody-colloidal gold label microplate can be obtained and stored in a sealed container.

[0078] 8. Preparation of sample absorption pads

[0079] The sample absorption pad was soaked in 0.2 mol / L phosphate buffer containing 1% bovine serum albumin at pH 7.2 for 2 hours, and then dried at 37°C for 2 hours before use.

[0080] 9. Preparation of the reaction membrane

[0081] The omethoate hapten-OVA conjugate was coated onto the reaction membrane to form a detection line, and the goat anti-mouse anti-antibody was coated onto the reaction membrane to form a control line.

[0082] Coating process: The omethoate hapten-OVA conjugate was diluted to 1 mg / mL with 0.01 mol / L, pH 7.2 phosphate buffer and coated onto the nitrocellulose membrane as the detection line (T line) using a Bio-dot coating apparatus, with a coating volume of 1.0 μL / cm. The goat anti-mouse anti-antibody was diluted to 200 μg / mL with 0.01 mol / L, pH 7.2 phosphate buffer and coated onto the nitrocellulose membrane as the control line (C line) using a Bio-dot coating apparatus, with a coating volume of 1.0 μL / cm. The coated reaction membranes were dried at 37°C for 16 h for later use.

[0083] 10. Assembly of test strips

[0084] According to the appendix Figure 3 The test strip cross-section structure is shown. The sample absorption pad (1), reaction membrane (2), and absorbent pad (3) are sequentially pasted onto the PVC base plate (6). The end of the sample absorption pad is connected to the beginning of the reaction membrane, and the end of the reaction membrane is connected to the beginning of the absorbent pad. The beginning of the sample absorption pad is aligned with the beginning of the PVC base plate, and the end of the absorbent pad is aligned with the end of the PVC base plate. The reaction membrane has a detection line (4) and a control line (5). The detection line (T line) and the control line (C line) are both strips perpendicular to the length of the test strip. The detection line is located on the side near the end of the sample absorption pad. The control line is located on the side away from the end of the sample absorption pad. The test strip is cut into 3.95mm wide strips by machine and placed in a specially made plastic card.

[0085] According to the appendix Figure 4 The diagram shows a microporous reagent 7 with a microporous plug 8.

[0086] The test paper and the micropore reagent are assembled into a test strip, which is stored in an environment of 2-8°C and has an effective period of 12 months.

[0087] Example 2: Detection of omethoate in fruits and vegetables

[0088] 1. Sample pretreatment

[0089] Fresh samples are taken, and the soil is wiped off. The samples are cut into pieces smaller than 1 cm square. (2.00±0.05) g of the sample is weighed into a 15 mL centrifuge tube, 6 mL of the extraction solution is added, the cap is put on, and the sample is vortexed for 1 min or shaken up and down manually for 1 min. The sample is allowed to stand for 5 min to obtain the sample to be tested.

[0090] 2. Detection with the test strip

[0091] 100 μL of the sample to be tested is taken with a micropipette and slowly sucked into the micropore and mixed well with the reagent in the micropore. After incubation at room temperature (20-25°C) for 3 min, 100 μL of the mixed solution is dropped vertically into the sample addition hole. The reaction is started when the liquid flows, and the reaction is allowed to proceed for 10 min to determine the result.

[0092] 3. Analysis of the detection result

[0093] Negative (-): The color of the T line is higher than or equal to the color of the C line, indicating that the omethoate concentration in the sample is lower than the detection limit, such as Figure 5 a, 5b.

[0094] Positive (+): The color of the T line is lower than the color of the C line, or the T line does not develop color, indicating that the omethoate concentration in the sample is equal to or higher than the detection limit, such as Figure 5 c, 5d.

[0095] Invalid: The C line does not develop color, indicating incorrect operation or that the test strip has deteriorated, such as Figure 5 e, 5f.

[0096] Example 3: Sample detection examples

[0097] 1. Detection limit test

[0098] Blank pear, apple, leek, cowpea, and celery samples are taken, and omethoate is added to the samples to a final concentration of 0.01 mg / kg, 0.02 mg / kg, and 0.04 mg / kg, respectively. The test strip is used for detection, and each sample is determined three times.

[0099] When the test paper strip is used to detect the pear, apple, leek, cowpea and celery samples, the T line color on the test paper strip is higher than or equal to the C line color when there is no omethoate or the added concentration of omethoate is 0.01 mg / kg, which is negative; when the added concentration of omethoate is 0.02 mg / kg or 0.04 mg / kg, the T line color on the test paper strip is lower than the C line color or the T line is not colored, which is positive, indicating that the detection limit of the test paper strip for omethoate in fruits and vegetables is 0.02 mg / kg, which meets the maximum residue limit specified in the national standard GB 2763.

[0100] 2. False positive rate and false negative rate test

[0101] 20 samples of blank pear, apple, leek, cowpea and celery samples and 20 samples of positive pear, apple, leek, cowpea and celery samples with added omethoate to a final concentration of 0.02 mg / kg are taken, and the test paper strips produced in three batches are used for detection respectively, and the positive and negative rates are calculated.

[0102] The results show that when the test paper strips produced in three batches are used to detect the positive pear, apple, leek, cowpea and celery samples, the results are all positive, and the positive coincidence rate is 100% and the false negative rate is 0; when the test paper strips produced in three batches are used to detect the blank pear, apple, leek, cowpea and celery samples, the results are all negative, and the negative coincidence rate is 100% and the false positive rate is 0. It is proved that the test paper strip of the application can rapidly detect the omethoate residue in fruits and vegetables.

[0103] 3. Specificity test

[0104] When the test paper strip is used to detect 4 mg / kg of dimethoate, the T line color on the test paper strip is lower than the C line color or the T line is not colored, which is positive, indicating that the cross-reactivity of the test paper strip to dimethoate is 0.5%; when 10 mg / kg of other similar substances such as fenitrothion, chlorothalonil, phosmet, methyl parathion, triazophos and chlorpyrifos are detected, the T line color on the test paper strip is deeper than the C line color, which is negative, indicating that the test paper strip has small cross-reaction to these structural analogues and good specificity.

Claims

1. A test strip for detecting omethoate, comprising a test strip and a microwell reagent, wherein the test strip comprises a reaction membrane, a sample absorption pad, an absorbent pad, and a base plate; the reaction membrane has a detection line coated with an omethoate hapten-carrier protein conjugate and a control line coated with goat anti-mouse anti-antibody; the microwell reagent contains a lyophilized omethoate monoclonal antibody-colloidal gold label; the omethoate monoclonal antibody is prepared using the omethoate hapten-carrier protein conjugate as an immunogen; the omethoate hapten-carrier protein conjugate is obtained by conjugating the omethoate hapten with a carrier protein, wherein the carrier protein is bovine serum albumin, ovalbumin, hemocyanin, or human serum albumin; characterized in that... The method for synthesizing the omethoate hapten is as follows: Dissolve 2.13 g of omethoate in 80 mL of pyridine. Under nitrogen protection, add 5 mL of a pyridine solution containing 1.08 g of acryloyl chloride dropwise. React at 60 °C for 4 h. Stop the reaction, remove pyridine by rotary evaporation, dissolve in toluene, and remove by rotary evaporation to completely remove pyridine, yielding a yellow oily substance. Column the substance onto a silica gel column and elute with a 10:1 (v / v) dichloromethane-methanol mixture to obtain the omethoate hapten, whose molecular structure is:

2. The test strip as described in claim 1, characterized in that, The test paper is composed of a sample absorption pad, a reaction membrane, and an absorbent pad, which are sequentially adhered to a base plate. The microporous reagent has a microporous plug.

3. A method for preparing the test strip according to any one of claims 1-2, characterized in that, Includes the following steps: 1) Microporous reagent for preparing lyophilized dimethoate monoclonal antibody-colloidal gold label; 2) Prepare a reaction membrane with a detection line coated with an aerobic dimethoate hapten-carrier protein conjugate and a control line coated with goat anti-mouse anti-antibody; 3) Assemble the reaction membrane prepared in 2) with the sample absorption pad, water absorption pad, and base plate to form a test paper; 4) Assemble the lyophilized dimethoate monoclonal antibody-colloidal gold-labeled microwell reagent and test strip prepared in 1) and 3) into a test strip.

4. A method for detecting omethoate residues in fruits and vegetables using the test strip according to any one of claims 1-2, characterized in that, Includes the following steps: 1) Sample pretreatment; 2) Detection is performed using the test strip according to any one of claims 1-2; 3) Analyze the test results.

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