Method for detecting pesticide residues in vegetables
Vegetable samples were treated through freeze-drying and low-temperature high-speed centrifugation, combined with macroporous resin particles and GC-MS detection, and the time pressure and manpower and material load problems of pesticide residue detection in vegetable samples were solved, and the detection efficiency and detection ability of various components were improved.
Patent Information
- Application Number
- CN202411290015.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-14
- Publication Date
- 2024-12-13
AI Technical Summary
In the prior art, pesticide residue detection for vegetable samples needs to be carried out in a short time, resulting in serious manpower and material loads and difficult sample storage, affecting detection efficiency.
After freeze-drying, samples were taken in batches, low-temperature high-speed centrifugation and agitation of macroporous resin particles. Combined with GC-MS detection, the sample processing process is simplified, the sample storage time is extended, and the detection workload is reduced.
The batch preprocessing and storage of samples is realized, which reduces the urgency of detection work, improves detection efficiency, and can detect multiple pesticide components at the same time.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of pesticide residue detection methods, and in particular to a method for detecting pesticide residues in vegetables. Background Art
[0002] Pyrethroid pesticides have significant insecticidal effects and are widely used in modern agriculture. Studies have shown that pyrethroids have a long residual period after use. Improper use will lead to high residual amounts and enter the human body with food (especially fresh vegetables). After entering the human body, they have obvious toxic effects on the body's immunity and cardiovascular system. Therefore, pyrethroid pesticides are the key detection targets of pesticide residues in vegetable agricultural products. In the prior art, a variety of detection technologies can be used to detect pyrethroid pesticide residues, such as gas chromatography, liquid chromatography, and a variety of detection methods. However, these methods generally require more complicated pre-treatment, and general vegetable samples cannot be stored for a long time. In order to avoid unnecessary troubles caused by the rotting of vegetable samples, it is necessary to process a large number of test samples in a relatively short time, which requires a large amount of manpower and material resources in a short time, increasing the detection workload. Summary of the invention
[0003] In view of the deficiencies in the prior art, the present invention provides a method for detecting pesticide residues in vegetables, which solves the problem in the prior art that pesticide residue detection in vegetable samples needs to be performed in a relatively short period of time, resulting in a heavy burden on manpower and material resources.
[0004] According to an embodiment of the present invention, a method for detecting pesticide residues in vegetables comprises: quantitatively sampling 10 g, followed by freeze drying, crushing into powder, then adding pure water to make the total weight 10 g, then performing low-temperature high-speed centrifugation, filtering the supernatant and then fixing the volume to 100 ml, then taking 15 ml and adding 1 g of macroporous resin particles and stirring for 15-20 min, then separating the macroporous resin particles, then adding 5 ml of dichloromethane solution to the macroporous resin particles and stirring for 15-20 min, and aspirating 1 ml for GC-MS detection.
[0005] Further, the sample includes stem and leaf tissues of vegetables.
[0006] Furthermore, the conditions for low-temperature high-speed centrifugation treatment are: 4°C, 13000r / min, and treatment for 10-20min.
[0007] Furthermore, both stirrings were magnetic stirring, with the first stirring speed being 200 r / min and the second stirring speed being 300 r / min.
[0008] Furthermore, the chromatography used an Agilent DB-5MS column, and the programmed temperature conditions were: 40°C for 1 min, then programmed to 250°C at 30°C / min, then to 280°C at 6°C / min, then to 300°C at 10°C / min, and maintained for 5 min; carrier gas: helium, purity ≥99.999%, flow rate 1.0 mL / min; injection port temperature: 280°C; injection mode: splitless injection; injection volume: 1 μL.
[0009] Furthermore, the mass spectrometry conditions were: electron bombardment source: 70 eV; ion source temperature: 280° C.; transfer line temperature: 280° C.; solvent delay: 3 min; scanning mode: positive ion scanning; detection mode: multiple reaction monitoring.
[0010] Furthermore, the pesticide includes one or more of tefluthrin, bifenthrin, and cypermethrin.
[0011] Furthermore, the freeze-drying conditions are: -18 to -20°C, and the drying process is 20-30 hours.
[0012] Compared with the prior art, the present invention has the following beneficial effects:
[0013] Batch sampling can be carried out first, then freeze-dried and stored, and then the normal progress can be installed for step-by-step testing, which will not increase the workload in a short period of time. This solves the problem in the prior art that pesticide residue testing of vegetable samples needs to be carried out in a relatively short period of time, resulting in a heavy burden on manpower and material resources. At the same time, multiple pesticide components can be detected, which also increases the efficiency of the testing work to a certain extent. DETAILED DESCRIPTION
[0014] The technical solution of the present invention is further described below in conjunction with embodiments.
[0015] The present embodiment provides a method for batch detection of multiple pesticide residues, which includes: quantitatively sampling 10g of vegetable stem and leaf samples, and then freeze-drying them at -18 to -20°C for 20-30h, then taking out the samples and crushing them into powder, adding pure water to the samples to make the total weight 10g, and then low-temperature high-speed centrifugation at 4°C and 13000r / min for 10-20min, filtering the supernatant with a 0.45μm filter membrane and then fixing the volume to 100ml, then taking 15ml and adding 1g of macroporous resin particles and stirring for 15-20min at a stirring speed of 200r / min, then separating the macroporous resin particles, and then adding 5ml of dichloromethane solution to the macroporous resin particles and stirring for 15-20min at a stirring speed of 300r / min, and taking 1ml for GC-MS detection; the chromatogram adopts Agilent DB-5MS chromatographic column, programmed temperature conditions: maintain at 40℃ for 1 min, then increase the temperature to 250℃ at 30℃ / min, then increase the temperature to 280℃ at 6℃ / min, then increase the temperature to 300℃ at 10℃ / min, and maintain for 5 min; carrier gas: helium, purity ≥99.999%, flow rate 1.0mL / min; inlet temperature: 280℃; injection mode: splitless injection; injection volume: 1μL; mass spectrometry conditions: electron bombardment source: 70eV; ion source temperature: 280℃; transfer line temperature: 280℃; solvent delay: 3min; scanning mode: positive ion scanning; detection mode: multiple reaction monitoring.
[0016] The following is a comparison of the test results of a specific embodiment:
[0017]
[0018]
[0019] Take Chinese cabbage as an example. “ / ” means not detected.
[0020] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.
Claims
1. A method for detecting pesticide residues in vegetables. It is characterized in that include: 10 g of the sample was quantitatively sampled, freeze-dried, crushed into powder, and then pure water was added to make the total weight 10 g. The sample was then centrifuged at low temperature and high speed. The supernatant was filtered and the volume was fixed to 100 ml. Then 15 ml was added with 1 g of macroporous resin particles and stirred for 15-20 min. The macroporous resin particles were separated. Then 5 ml of dichloromethane solution was added to the macroporous resin particles and stirred for 15-20 min. 1 ml was taken and then subjected to GC-MS detection.
2. The method for detecting pesticide residues in vegetables as claimed in claim 1, It is characterized in that The samples included stem and leaf tissues of vegetables.
3. The method for detecting pesticide residues in vegetables as claimed in claim 1, It is characterized in that The conditions for low-temperature high-speed centrifugation treatment are: 4°C, 13000r / min, and treatment for 10-20min.
4. The method for detecting pesticide residues in vegetables as claimed in claim 1, It is characterized in that The stirring was performed twice by magnetic stirring, the first stirring speed was 200 r / min, and the second stirring speed was 300 r / min.
5. The method for detecting pesticide residues in vegetables as claimed in claim 1, It is characterized in that The chromatography used an Agilent DB-5MS column, and the programmed temperature conditions were: 40 °C for 1 min, then programmed to 250 °C at 30 °C / min, then programmed to 280 °C at 6 °C / min, then programmed to 300 °C at 10 °C / min, and maintained for 5 min; Carrier gas: helium, purity ≥99.999%, flow rate 1.0mL / min; injection port temperature: 280℃; injection mode: splitless injection; injection volume: 1μL.
6. The method for detecting pesticide residues in vegetables as claimed in claim 5, It is characterized in that The mass spectrometry conditions were as follows: electron bombardment source: 70 eV; ion source temperature: 280°C; transfer line temperature: 280°C; solvent delay: 3 min; scanning mode: positive ion scanning; detection mode: multiple reaction monitoring.
7. The method for detecting pesticide residues in vegetables as claimed in claim 1, It is characterized in that The pesticides include one or more of tefluthrin, bifenthrin, and cypermethrin.
8. The method for detecting pesticide residues in vegetables according to any one of claims 1 to 7, It is characterized in that The freeze-drying conditions are: -18 to -20°C, drying for 20-30 hours.