A rapid quantitative detection method for harmful residues of agricultural products

Abstract

The application relates to the technical field of food detection, in particular to a rapid quantitative detection method for harmful residues of agricultural products. 3+ S1: after sample crushing, extraction is carried out through an acetonitrile-carbonic acid-PBS mixed solution, and oil samples are defatted by n-hexane; S2: 5nm CdTe fluorescent quantum dots are ultrasonically compounded with Eu A long-acting immunological probe is prepared by coupling six contaminant specific antibodies through EDC / NHS according to a mass ratio of 1:2; S3: constant temperature competition immunization and washing are carried out on a multi-antigen microwell plate; S4: signals are collected by a time-resolved fluorescence instrument, and multistage operations of base deduction, spectral decoupling, quenching compensation, nonlinear fitting and matrix correction are sequentially carried out; and S5: comparison and grading determination are carried out according to a national standard. Chlorpyrifos, carbofuran, sulfadiazine, enrofloxacin, aflatoxin B1 and vomitoxin can be synchronously detected, and the method is suitable for vegetables, livestock and poultry meat and grains; the method is rapid in detection, resistant to matrix interference and suitable for primary site batch screening.

Description

Technical Field

[0001] This invention relates to the field of food testing technology, and in particular to a rapid quantitative detection method for harmful residues in agricultural products. Background Technology

[0002] Vegetables, livestock and poultry meat, and grains are the basic bulk agricultural products in the residents' diet, covering the entire industrial chain from planting and livestock and poultry breeding to grain storage. In vegetable planting, farmers use large amounts of organophosphates and carbamates to control pests and diseases; in livestock and poultry breeding, the illegal feeding of sulfonamides and quinolone veterinary drugs is widespread; and grains such as corn and wheat are highly susceptible to mold growth under high temperature and humidity storage and transportation conditions, producing potent carcinogenic fungal toxins such as aflatoxin and vomitoxin. If the residues of these three types of harmful substances exceed the national food safety limits, long-term intake can damage the human liver, kidneys, and hematopoietic system, and even induce cancer. Therefore, routine, rapid, and accurate quantitative screening of residues in all categories of agricultural products is a rigid requirement for food safety supervision.

[0003] Currently, the main methods for detecting harmful residues in agricultural products are divided into two categories: large-scale instrumental confirmatory methods and rapid immunoassay methods. Large-scale chromatography-mass spectrometry (GC-MS) confirmatory detection technology offers high quantitative accuracy and low detection limits, and is a national standard arbitration method. However, the equipment purchase and maintenance costs are hundreds of thousands of yuan, pretreatment takes 1-2 hours, and it requires professionally certified testing personnel. It cannot achieve on-site, large-scale screening, making it unsuitable for widespread use in township regulatory offices, small food production enterprises, and farmers' markets. Traditional single-fluorescence immunoassay methods suffer from drawbacks such as easy photobleaching of individual organic fluorescent dyes and strong interference from the autofluorescence of agricultural product matrices; single CdTe quantum dots lack time-resolved, long-lifetime anti-interference capabilities, and fluorescence continuously decays after prolonged instrument excitation and scanning; single Eu... 3+ Rare earth microspheres exhibit insufficient fluorescence intensity and high detection limits in complex matrices rich in pigments and proteins. None of the three types of single-labeling materials can simultaneously achieve the triple advantages of high luminescence intensity, long fluorescence lifetime, and resistance to photoquenching. Commercially available reagent kits only support the independent detection of a single pollutant. Simultaneous screening for pesticides, veterinary drugs, and mycotoxins requires multiple sets of reagents and multiple instrument runs, significantly increasing time and material costs, and resulting in extremely low efficiency for batch sampling. Summary of the Invention

[0004] To address the shortcomings of existing technologies, a rapid quantitative detection method for harmful residues in agricultural products is provided. This method enables simultaneous and accurate quantification of multiple harmful residues in multi-matrix agricultural products such as vegetables, livestock and poultry meat, and grains. It also has the advantages of high sensitivity, stable storage, fast detection speed, and strong resistance to matrix interference.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is a rapid quantitative detection method for harmful residues in agricultural products, comprising the following steps: S1. Sample pretreatment: After crushing agricultural product samples, add the extract, and obtain the supernatant solution to be tested by shaking, sonication, and centrifugation; oil samples are first defatted with n-hexane; S2. Preparation of immune probes: Quantum dots are combined with time-resolved fluorescent materials to obtain markers, and the markers are coupled with antibodies specific to multiple pollutants to prepare immune probes. S3. Immunological reaction: The test solution and the immune probe are mixed and added to the coated antigen microplate. The mixture is reacted at a constant temperature and then washed. S4. Quantitative fluorescence analysis: The original fluorescence signal was acquired using a time-resolved fluorescence device, and the residual concentration was obtained by sequentially undergoing quenching compensation, nonlinear fitting, and matrix correction. S5. Result determination: Compare the corrected concentration with the national standard limit to determine whether the sample is qualified or exceeds the standard; the agricultural products mentioned include three categories: vegetables, livestock and poultry meat, and grains.

[0006] The above-mentioned rapid quantitative detection method for harmful residues in agricultural products uses the quantum dot fluorescence quenching compensation operation formula as follows: Y 补偿 =Y 校正信号 ·e λ·t ; In the formula: Y 校正信号 The fluorescence signal after preprocessing; Y 补偿 λ represents the fluorescence value used for curve fitting after quenching compensation; t represents the duration of a single instrument scan in seconds; λ represents the quantum dot quenching rate constant, ranging from 0.002 to 0.008 s. -1 .

[0007] The above-mentioned rapid quantitative detection method for harmful residues in agricultural products uses the following nonlinear fitting curve operation formula: Y=a·X b +c; In the formula: Y is the fluorescence signal intensity; X is the concentration of harmful residues; a takes a value of 1000 to 5000, b takes a value of 0.8 to 1.2, and c takes a value of 50 to 200. a, b, and c are obtained by fitting the test data of the standard.

[0008] The matrix correction formula for the above-mentioned rapid quantitative detection method for harmful residues in agricultural products is as follows: X 校正 =X 检测 / K; In the formula: X 检测 The original concentration is derived from the standard curve; K is the matrix interference correction coefficient, ranging from 0.85 to 0.95, calibrated by adding a blank matrix.

[0009] In the above-mentioned rapid quantitative detection method for harmful residues in agricultural products, in step S2, the quantum dots are 5nm CdTe quantum dots, and the time-resolved fluorescent material is Eu. 3+-β-diketone complex, with a composite mass ratio of 1:2; the composite process involves ultrasonication at 300-500W for 10-15 minutes, followed by coupling at 25-30℃ for 2-4 hours using an EDC / NHS system; the resulting probe is stable at 4℃ in the dark for ≥3 months.

[0010] In the above-mentioned rapid quantitative detection method for harmful residues in agricultural products, in step S3, the concentration of antigen coating on the microplate is 1-5 μg / mL, and the coating time is 4℃ for 12-16 h; the immunoreaction temperature is 37℃, and the reaction time is 10-15 min; the washing buffer contains 0.05% Tween-20, and the washing is performed 3 times.

[0011] In the above-mentioned rapid quantitative detection method for harmful residues in agricultural products, in step S1, the supernatant test solution is a mixture of acetonitrile and phosphate with a volume ratio of 3:1, and 0.1% formic acid is added; the centrifugation speed is 4000-5000 r / min, the centrifugation time is 5 min, the vortex oscillation is 5-10 min, and the ultrasonic extraction is 3-5 min.

[0012] In the above-mentioned rapid quantitative detection method for harmful residues in agricultural products, the time-resolved fluorescence device parameters in step S4 are: excitation wavelength 365nm, emission wavelength 610nm, fluorescence delay 100μs, and single detection duration 200μs.

[0013] The above-mentioned rapid quantitative detection method for harmful residues in agricultural products can simultaneously detect six targets: chlorpyrifos, carbofuran, sulfadiazine, enrofloxacin, aflatoxin B1, and vomitoxin. The method has a detection limit of 0.01–0.05 ng / mL, a quantitation limit of 0.03–0.15 ng / mL, a spiked recovery rate of 85%–95%, and an RSD ≤ 5%.

[0014] The beneficial effect of this invention's rapid quantitative detection method for harmful residues in agricultural products is that CdTe quantum dots combined with Eu... 3+ The β-diketone complex is ultrasonically compounded in a 1:2 ratio, which combines the advantages of high brightness of quantum dots and long lifespan of rare earth elements to resist background interference. The immune probe can be stored stably at 4°C in the dark for no less than 3 months, with a detection limit as low as 0.01 ng / mL, making it suitable for trace residue screening.

[0015] The extraction solution is acetonitrile:PBS = 3:1 with the addition of 0.1% formic acid. For oily and meat products, an additional hexane defatting step is added. The process is compatible with three types of substrates: vegetables, livestock and poultry meat, and grains.

[0016] Employing a power function nonlinear model, coupled with a complete calculation chain including dedicated quenching compensation, product-specific matrix correction, substrate noise reduction, crosstalk decoupling, secondary calibration, and risk grading, the retest RSD is ≤5%, significantly reducing quantitative errors.

[0017] The parameters for fluorescence-based ultrasound, EDC / NHS antibody conjugation, and microwell antigen coating are clearly defined, ensuring high process repeatability and facilitating standardized mass production of the kit.

[0018] The entire testing process can be completed within 30 minutes, without the need for large-scale mass spectrometry equipment. It can be operated immediately on-site by grassroots regulatory offices and food companies, and the testing cost is low. Attached Figure Description

[0019] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0021] As shown in the figure, a rapid quantitative detection method for harmful residues in agricultural products includes the following steps: S1. Sample pretreatment: Take the agricultural product sample to be tested, crush it, add the extraction solution, vortex for 5-10 min, extract with ultrasound for 3-5 min, centrifuge at 4000-5000 r / min for 5 min, and take the supernatant as the test solution; for oily livestock and poultry meat samples, first add n-hexane to defatt them, and then perform the extraction operation; the extraction solution is a mixture of acetonitrile and phosphate buffer at a volume ratio of 3:1, and add 0.1% formic acid to improve the extraction efficiency of residues; The acetonitrile-phosphate buffer system is polarly compatible with various residues, and formic acid can improve the dissolution rate of weakly polar pesticides and fungal toxins, effectively increasing the recovery rate compared with single aqueous solution extraction. A hexane defatting process was added to remove the inhibitory effect of meat fat on immune binding and solve the problem of low recovery rate of oil samples. The combination of vortex and ultrasonic extraction eliminates the need for complex purification steps such as solid phase extraction and nitrogen blowing, reducing the pretreatment time to less than 10 minutes and significantly lowering the operational threshold. By using a uniform centrifugation speed and time, the supernatant achieves high clarity, preventing impurities from clogging the detection system and reducing interference from the fluorescent substrate.

[0022] S2. Preparation of multi-component immunoprobes: 5nm CdTe quantum dots and Eu... 3+ -β-diketone time-resolved fluorescent materials were mixed at a mass ratio of 1:2 and ultrasonically dispersed at 300-500W for 10-15 min to form bifunctional fluorescent labels. Using an EDC / NHS activation covalent coupling process, the reaction was carried out at 25-30℃ for 2-4 h. The labels were then conjugated with specific monoclonal antibodies against chlorpyrifos, carbofuran (pesticide), sulfadiazine, enrofloxacin (veterinary drug), aflatoxin B1, and vomitoxin (fungal toxin). The resulting multi-component immunoprobes were dispersed in phosphate buffer containing 1% bovine serum albumin and stored at 4℃ in the dark, sealed for at least 3 months. A 1:2 combination of CdTe quantum dots and rare earth fluorescent materials combines the high luminescence intensity of quantum dots with the long-lifetime fluorescence and anti-background interference characteristics of rare earth materials, resulting in a significant reduction in the detection limit compared to single rare earth labeling. • Limiting ultrasonic power and time ensures uniform dispersion of markers without aggregation, avoiding detection bias caused by uneven fluorescence signals; • Mild EDC / NHS coupling conditions protect antibody activity and probe specificity; BSA blocks the non-specific binding sites of the marker, and the probe can be stored at 4°C for up to 90 days, which is far superior to the 1-month shelf life of conventional fluorescent probes, reducing the storage loss of the kit.

[0023] S3. Immunoassay: The test solution and multi-component immunoprobe are mixed at a volume ratio of 1:1 and added to a multi-antigen coated microplate. The antigen coating concentration in the microplate is 1-5 μg / mL. The coating is carried out overnight at 4°C for 12-16 h. The reaction is carried out at 37°C with shaking for 10-15 min. After the reaction, the microplates are washed three times with phosphate buffer containing 0.05% Tween-20 to remove unspecifically bound free probes. • Multi-antigen co-coated microplates enable simultaneous competitive immunization of six targets on a single plate, eliminating the need for multiple tests on separate plates and effectively improving batch testing efficiency; • Low-temperature overnight coating results in stronger binding of the antigen to the solid-phase carrier and better signal repeatability between batches; • Constant temperature oscillation at 37℃ accelerates the competitive binding of antigen and antibody, with the reaction time controlled within 15 minutes; The Tween-20 washing system effectively elutes non-specifically adsorbed free probes, reduces blank fluorescence background, and decreases the probability of false positives.

[0024] S4. Fluorescence Acquisition and Quantitative Calculation: Fluorescence signals were acquired using a time-resolved fluorescence detector with the following parameters: excitation wavelength 365 nm, emission wavelength 610 nm, delay time 100 μs, and single detection duration 200 μs. After acquiring the raw fluorescence signal, a complete set of calculation procedures was performed, including microporous substrate fluorescence subtraction, multi-component crosstalk matrix decoupling, quantum dot fluorescence quenching compensation, nonlinear standard curve fitting, matrix primary correction, and recovery rate secondary calibration, to obtain the true concentration of residues after double correction. Time-resolved parameters are matched to the optical properties of composite markers, automatically filtering out spontaneous short-lived fluorescence in agricultural products and significantly reducing substrate interference; A multi-level continuous correction algorithm is cascaded to eliminate multiple interferences from the substrate, spectral crosstalk, fluorescence attenuation, matrix suppression, and batch bias layer by layer; Unlike traditional univariate linear fitting, the power function nonlinear model perfectly matches the high and low concentration response patterns of the immune competition curve, effectively reducing the quantitative error between high and low concentrations. The matrix correction coefficient is categorized to differentiate the inhibition effects of different matrices in vegetables, meat, and starch, and is universally applicable to all tested agricultural products.

[0025] Quantum dot fluorescence quenching compensation operation formula: Y 补偿 =Y 校正信号 ·e λ·t ; In the formula: Y 校正信号 The fluorescence signal after preprocessing; Y 补偿 λ represents the fluorescence value used for curve fitting after quenching compensation; t represents the duration of a single instrument scan in seconds; λ represents the quantum dot quenching rate constant, ranging from 0.002 to 0.008 s. -1 .

[0026] Formula for nonlinear fitting curve operation: Y=a·X b +c; In the formula: Y is the fluorescence signal intensity; X is the concentration of harmful residues; a takes a value of 1000 to 5000, b takes a value of 0.8 to 1.2, and c takes a value of 50 to 200. a, b, and c are obtained by fitting the test data of the standard.

[0027] Matrix correction operation formula: X 校正 =X 检测 / K; In the formula: X 检测 The original concentration is derived from the standard curve; K is the matrix interference correction coefficient, ranging from 0.85 to 0.95, calibrated by adding a blank matrix.

[0028] The formula for fluorescence subtraction on microporous substrates is: ; The raw fluorescence readings are directly read by the instrument. The background fluorescence value of the blank micropore substrate; The base attenuation coefficient has a value of 0.90 to 0.98. This represents the pure basic fluorescence signal after removing substrate interference.

[0029] The formula for decoupling a multi-component crosstalk matrix is: Y 校正信号 =M -1 ·Y 有效 ; Y 有效 is the multidimensional fluorescence vector after basis subtraction; M is the crosstalk coupling matrix, with element coefficients ranging from 0.01 to 0.08; M -1 Y is the inverse of the coupling matrix; 校正信号 To eliminate the interference of spectral overlap and obtain a pure fluorescence signal.

[0030] Concentration back-calculation operation formula: ; The uncorrected original residual concentration was calculated by reverse calculation of the compensated fluorescence value. .

[0031] Secondary calibration formula for recovery rate: ; S5. Result determination: Compare the corrected residue content with the national food safety standard limit to determine whether the sample is qualified or exceeds the standard. Formula for determining residual risk classification: ; RI risk index; L corresponds to the national standard limit for residues; RI < 0.5 indicates low risk, 0.5 ≤ RI indicates warning, and RI ≥ 1 indicates exceeding the standard.

[0032] This invention is applicable to the following agricultural products: vegetables (fresh vegetables such as bok choy, lettuce, and cabbage), livestock and poultry meat (pork, chicken, beef, etc.), and grains (corn, wheat, rice, etc.). The method's performance indicators are: detection limits for each target are 0.01–0.05 ng / mL, quantitation limits are 0.03–0.15 ng / mL, spiked recoveries are 85%–95%, and the relative standard deviation (RSD) of the detection results is ≤5%. Example 1

[0033] Detection of Chlorpyrifos Residue in Green Vegetables (Vegetable Substrate) Sample pretreatment: Weigh 5g of crushed green vegetable sample, add 10mL of extraction solution (acetonitrile: phosphate buffer = 3:1, containing 0.1% formic acid), vortex for 8min, sonicate for 4min, centrifuge at 4500r / min for 5min. Since the green vegetable is oil-free, defatting is not necessary. Take the supernatant directly for testing.

[0034] Preparation of immunoprobes: CdTe quantum dots and Eu³⁺-β-diketone complex were mixed at a mass ratio of 1:2 and ultrasonicated at 400W for 12 min to prepare composite markers; EDC / NHS system was used for constant temperature coupling at 28℃ for 3 h to obtain chlorpyrifos-specific immunoprobes, which were then stored at 4℃ in the dark for later use.

[0035] Microplate immunoassay: Vegetable supernatant was mixed with immunoprobe at a volume ratio of 1:1 and added to a microplate coated with antigen at a concentration of 3 μg / mL and coated at 4℃ for 14 h. The plate was then incubated at 37℃ with shaking for 12 min. The plate was washed three times with 0.05% Tween-20 phosphate buffer.

[0036] Fluorescence acquisition and stepwise calculation: Instrument parameters were set to excitation 365nm, emission 610nm, delay 100μs, and single scan 200μs, and the raw fluorescence was read. ①Base subtraction: Substitute η is taken as 0.94; ② Matrix decoupling operations eliminate cross-interference in the spectra of multiple probes, yielding Y. 校正信号 ; ③Quenching compensation: Substitute Y 补偿 =Y 校正信号 ·e λ·t λ=0.005S -1 , t=0.2s; ④ The nonlinear curve fitting parameters a=2860, b=0.92, c=110 are substituted into the concentration back-calculation formula for calculation. ; ⑤ The substrate correction coefficient for leafy greens, K = 0.91, is substituted into the first-level correction formula to obtain X. 校正 ; ⑥ Based on the measured recovery rate of this batch of green vegetables, substitute it into the secondary calibration formula to obtain X. 最终 ; ⑦ Calculate the risk index RI=X 最终 / L, compared with the national standard limit to complete the classification determination.

[0037] Test results: The spiked value of the vegetable substrate was 0.1 ng / g, and the actual value measured by this method was 0.096 ng. The spiked recovery rate was 96%, and the RSD of 6 parallel tests was 3.2%. Example 2

[0038] Detection of sulfadiazine veterinary drugs in pork (high-fat livestock and poultry matrix) The parts that are the same as those in Example 1 will not be repeated here. The differences are as follows: • Pretreatment: Weigh 5g of minced pork, add 5mL of n-hexane and vortex for 5min to defatt it, discard the upper oil phase, add the extract, shake, sonicate, and centrifuge to obtain the supernatant; pork matrix correction coefficient K=0.88.

[0039] The immune probe was replaced with a sulfadiazine-specific probe, and the fluorescence acquisition and complete formula calculation process were the same as in Example 1. Example 3

[0040] The parts that are the same as those in Example 1 will not be repeated here. The differences are as follows: • Pretreatment: Corn is fat-free and does not require defatting; it is extracted directly; grain matrix correction coefficient K=0.93.

[0041] Stability verification: After the composite probe was stored at 4℃ in the dark for 90 days, the fluorescence signal attenuation was less than 8%, and the quantitative results showed no significant shift after correction with the quenching compensation formula. Example 4

[0042] Batch multi-target synchronous detection verification The parts that are the same as in Example 1 will not be repeated here. The differences are as follows: Three blank matrix samples of vegetables, pork, and corn were taken respectively. Six mixed standards of chlorpyrifos, carbofuran, sulfadiazine, enrofloxacin, aflatoxin B1, and vomitoxin were added to each matrix sample simultaneously. The complete detection process of this invention was used to simultaneously measure the samples. The whole operation took only 28 minutes. The same sample was tested separately 6 times using a commercially available single-target reagent kit. The total time took more than 90 minutes, and the amount of consumables used was increased by 3.6 times.

[0043] The complete data for the limits of detection, average spiked recoveries, and parallel detection RSDs for each target in the three types of matrices are as follows:

[0044] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A rapid quantitative detection method for harmful residues in agricultural products, characterized in that, Includes the following steps: S1. Sample pretreatment: After crushing agricultural product samples, add the extract, and obtain the supernatant solution to be tested by shaking, sonication, and centrifugation; oil samples are first defatted with n-hexane; S2. Preparation of immune probes: Quantum dots are combined with time-resolved fluorescent materials to obtain markers, and the markers are coupled with antibodies specific to multiple pollutants to prepare immune probes. S3. Immunological reaction: The test solution and the immune probe are mixed and added to the coated antigen microplate. The mixture is reacted at a constant temperature and then washed. S4. Quantitative fluorescence analysis: The original fluorescence signal was acquired using a time-resolved fluorescence device, and the residual concentration was obtained by sequentially undergoing quenching compensation, nonlinear fitting, and matrix correction. S5. Result determination: Compare the corrected concentration with the national standard limit to determine whether the sample is qualified or exceeds the standard; The agricultural products mentioned include three categories: vegetables, livestock and poultry meat, and grains.

2. The rapid quantitative detection method for harmful residues in agricultural products according to claim 1, characterized in that, Quantum dot fluorescence quenching compensation operation formula: AND 补偿 =Y 校正信号 ·and λ·t ; In the formula: Y 校正信号 The fluorescence signal after preprocessing; Y 补偿 The fluorescence value used for curve fitting after quenching compensation; t is the duration of a single instrument scan, in seconds; λ is the quantum dot quenching rate constant, ranging from 0.002 to 0.008 s. -1 .

3. The rapid quantitative detection method for harmful residues in agricultural products according to claim 2, characterized in that, Formula for nonlinear fitting curve operation: Y=a·X b +c; In the formula: Y is the fluorescence signal intensity; X is the concentration of harmful residues; a takes a value of 1000 to 5000, b takes a value of 0.8 to 1.2, and c takes a value of 50 to 200. a, b, and c are obtained by fitting the test data of the standard.

4. The rapid quantitative detection method for harmful residues in agricultural products according to claim 3, characterized in that the matrix... Correction operation formula: X 校正 =X 检测 / K; In the formula: X 检测 The original concentration is derived from the standard curve; K is the matrix interference correction coefficient, ranging from 0.85 to 0.95, calibrated by adding a blank matrix.

5. The rapid quantitative detection method for harmful residues in agricultural products according to claim 4, characterized in that, In step S2, the quantum dots are 5nm CdTe quantum dots, and the time-resolved fluorescent material is Eu. 3+ The β-diketone complex was prepared with a mass ratio of 1:

2. The composite process involved sonication at 300–500 W for 10–15 min, followed by coupling at 25–30 °C for 2–4 h using an EDC / NHS system. The resulting probe was stable for ≥3 months when stored at 4 °C in the dark.

6. The rapid quantitative detection method for harmful residues in agricultural products according to claim 5, characterized in that, In step S3, the antigen coating concentration of the microplate is 1-5 μg / mL, and the coating time is 4℃ for 12-16 h; the immune reaction temperature is 37℃, and the reaction time is 10-15 min; the washing buffer contains 0.05% Tween-20, and the washing is performed 3 times.

7. The rapid quantitative detection method for harmful residues in agricultural products according to claim 6, characterized in that the steps are as follows: In S1, the supernatant test solution is a mixture of acetonitrile and phosphate with a volume ratio of 3:1, and 0.1% formic acid is added; the centrifugation speed is 4000-5000 r / min, the centrifugation time is 5 min, the vortexing is 5-10 min, and the ultrasonic extraction is 3-5 min.

8. The rapid quantitative detection method for harmful residues in agricultural products according to claim 7, characterized in that, In step S4, the time-resolved fluorescence device parameters are: excitation wavelength 365nm, emission wavelength 610nm, fluorescence delay 100μs, and single detection duration 200μs.

9. The rapid quantitative detection method for harmful residues in agricultural products according to claim 8, characterized in that, This method can simultaneously detect six targets: chlorpyrifos, carbofuran, sulfadiazine, enrofloxacin, aflatoxin B1, and vomitoxin. The method detection limit is 0.01–0.05 ng / mL, the quantitation limit is 0.03–0.15 ng / mL, the spiked recovery rate is 85%–95%, and the RSD of the detection results is ≤5%.

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