CN114910588B - Synchronous detection method for couchgrass, dicamba, penta-nitrophenol, fenpyroxim and penconazole in tea - Google Patents
Synchronous detection method for couchgrass, dicamba, penta-nitrophenol, fenpyroxim and penconazole in tea Download PDFInfo
- Publication number
- CN114910588B CN114910588B CN202210522528.XA CN202210522528A CN114910588B CN 114910588 B CN114910588 B CN 114910588B CN 202210522528 A CN202210522528 A CN 202210522528A CN 114910588 B CN114910588 B CN 114910588B
- Authority
- CN
- China
- Prior art keywords
- tea
- dicamba
- phase
- penconazole
- sample
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/04—Preparation or injection of sample to be analysed
- G01N30/06—Preparation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/62—Detectors specially adapted therefor
- G01N30/64—Electrical detectors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/62—Detectors specially adapted therefor
- G01N30/72—Mass spectrometers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/86—Signal analysis
- G01N30/8624—Detection of slopes or peaks; baseline correction
- G01N30/8631—Peaks
- G01N30/8637—Peak shape
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/04—Preparation or injection of sample to be analysed
- G01N30/06—Preparation
- G01N2030/065—Preparation using different phases to separate parts of sample
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/30—Against vector-borne diseases, e.g. mosquito-borne, fly-borne, tick-borne or waterborne diseases whose impact is exacerbated by climate change
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
- Agricultural Chemicals And Associated Chemicals (AREA)
- Investigating Or Analysing Biological Materials (AREA)
Abstract
The invention belongs to the technical field of pesticide residue detection, and discloses a synchronous detection method for couchgrass, dicamba, pentanitol, indoxacarb and penconazole in tea. Mixing water, formic acid and acetonitrile mixed solution for vortex mixing extraction, adding sodium chloride for vortex mixing, and centrifuging; adding anhydrous magnesium sulfate, GCB and C18 powder into the supernatant, vortex mixing, purifying and centrifuging; controlling the ratio of the tea leaf sample to water, formic acid, acetonitrile and sodium chloride to be 1 g:5-7.5 mL:0.10-0.15 mL:10-15 mL:2-3 g; impurities can be removed by this specific treatment method and only the target product remains. The detection limit of an instrument for detecting 5 pesticides is 0.1-0.8 ng/mL, the detection limit of a method is 0.1-0.8 mug/kg, and the correlation coefficient R 2 More than or equal to 0.999, the method has practical application for detecting the residue of the thatch, the dicamba, the pentanitol, the indoxacarb and the phenol in the tea.
Description
Technical Field
The invention belongs to the technical field of pesticide residue detection, and particularly relates to a synchronous detection method for couchgrass, dicamba, pentanitol, fenpyroxim and penconazole in tea.
Background
The tea is rich in tea polyphenol, catechin, flavone and other substances, and has the effects of refreshing, clearing heat and detoxicating and the like, so the tea is deeply favored by people. In the growth process of tea, tea farmers spray pesticides on tea trees for weeding and pest removal. In order to meet the strict standards of maximum residual quantity of pesticides in tea leaves at home and abroad, and ensure the quality safety of the tea leaves, the maximum residual quantity of pesticides in the tea leaves is up to 106 in the standard of maximum residual quantity of pesticides in food safety national Standard food (GB 2763-2021) which is formally implemented in 9 months and 3 days of 2021. Wherein the temporary maximum residual limit values of the newly added couchgrass cake, the dicamba, the penta-nitrophenol, the fenpyroxim and the penconazole in the tea are all 0.01mg/kg.
Up to now, related standards or literature reports of methods for detecting couchgrass, dicamba, pentanitrophenol, indoxacarb and penconazole in tea leaves are not yet available at home and abroad. The only standard and literature reports about the detection method of the coumargrass, the dicamba, the pentanitrophenol, the fenpyroxim and the penconazole mainly aim at the determination of the coumargrass or the dicamba in water quality or soil, the detection method is to extract the coumargrass or the dicamba in a sample by adopting dichloromethane or a solid phase extraction small column, re-dissolve the coumargrass or the dicamba by using concentrated acetone, then derivatize the coumargrass or the dicamba by adopting pentafluorobenzyl bromide, then purifying the derivative by a column, re-dissolving the sample, and finally determine the coumargrass or the dicamba by adopting a gas chromatography or gas chromatography tandem mass spectrometry. The detection method uses a large amount of organic solvents, and the sample pretreatment process is complex, long in time consumption, high in cost and limited in detection items. For three detection items of the pentanitrophenol, the fenpyroximate and the penconazole, no related literature report exists in water quality or soil at present, and the detection method is in a technical blank point.
Therefore, there is a need to establish a sensitive, accurate, efficient and convenient synchronous detection method for the pesticide residues of the coumarone, the dicamba, the penta-nitrophenol, the indomethacin and the penconazole in the tea leaves so as to fill up the technical blank points of the pesticide residues of the coumarone, the dicamba, the penta-nitrophenol, the penconazole and the penconazole in the tea leaves, and provide a powerful technical support means for the residue detection of the coumarone, the dicamba, the penta-nitrophenol, the penconazole and the penconazole in the tea leaves in China.
Disclosure of Invention
The invention aims to fill the technical blank point of residual detection of coumarone, dicamba, penta-nitrophenol, tebuconazole and penconazole in the existing tea, and provides a novel synchronous detection method of coumarone, dicamba, penta-nitrophenol, tebuconazole and penconazole in the tea.
Specifically, the invention provides a synchronous detection method of couchgrass, dicamba, pentanitrophenol, indoxacarb and penconazole in tea, wherein the method comprises the following steps:
s1: sample pretreatment
Weighing a proper amount of tea samples to be tested, putting the tea samples into a centrifuge tube, performing vortex mixing extraction by adopting a mixed solution of water, formic acid and acetonitrile, adding sodium chloride, performing vortex mixing, and centrifuging to obtain a product I; adding anhydrous magnesium sulfate, GCB and C18 powder into the supernatant, vortex mixing, purifying and centrifuging II; collecting supernatant, blowing nitrogen to dryness at 35-45 ℃, adding 25-35% v/v methanol aqueous solution for re-dissolution, and finally filtering with a 0.1-0.3 mu m filter membrane to obtain a sample solution to be detected, and reserving for LC-MS/MS detection; wherein the ratio of the tea sample to be tested to water, formic acid, acetonitrile and sodium chloride is 1g (5-7.5) mL (0.10-0.15) mL (10-15) mL (2-3) g; the ratio of the tea leaf sample to be tested to anhydrous magnesium sulfate, GCB and C18 powder is 1g (600-900 mg) (200-300 mg) (100-150 mg);
s2: preparing standard solution of matrix
Taking a negative blank tea sample, and performing sample pretreatment according to the step S1 to obtain a matrix blank solution; dissolving standard substances of coumarone, dicamba, pentanitrophenol, fenpyroxim and penconazole in a solvent, and preparing a series of matrix mixed standard solutions with concentration gradients of 2-50 ng/mL respectively by using a matrix blank solution;
s3: sample detection
Carrying out LC-MS/MS measurement on the mixed standard solution of the matrix of the coumarone, the dicamba, the penta-nitrophenol, the fenpyroximate and the virulent phenol in the step S2 to obtain a matrix standard working curve; and (3) carrying out LC-MS/MS determination on the sample solution to be detected in the step (S1), quantifying by adopting a matrix standard curve external standard method, and comparing the obtained detection curve with a standard working curve to obtain the contents of coumarone, dicamba, pentanitrophenol, indomethacin and penconazole in the tea sample to be detected.
It should be noted that, in the present invention, for convenience of description, the two centrifugation in the sample pretreatment process is referred to as "centrifugation I" and "centrifugation II" for the purpose of distinguishing different objects only, and should not be construed as indicating or implying relative importance thereof. The negative blank tea sample is a tea sample with the contents of couchgrass, dicamba, pentanitrophenol, indoxacarb and penconazole lower than the detection limit of an experimental method.
In a preferred embodiment, in step S1, the condition of the vortex mixing extraction is vortex for 10 to 15min.
In a preferred embodiment, the condition of vortex mixing is vortex 30-60 s.
In a preferred embodiment, the vortex mixing and purifying conditions are vortex 60-90 s.
In a preferred embodiment, in step S1, the conditions of the centrifugation I include a centrifugation speed of 10000 to 20000rpm and a centrifugation time of 5 to 10min.
In a preferred embodiment, the conditions of the centrifugation II comprise a centrifugation speed of 10000-20000 rpm and a centrifugation time of 5-10 min.
In a preferred embodiment, in step S1, the filter is an organic filter having a pore size of 0.22. Mu.m.
In a preferred embodiment, in step S3, the LC-MS/MS measurement process liquid chromatography conditions include: the chromatographic column is Waters BEH C18; the column temperature is 35 ℃; the flow rate is 0.30mL/min; the sample injection amount is 5 mu L; the mobile phase was eluted with a gradient using aqueous formic acid at a concentration of 0.02% v/v as phase A and methanol as phase B and the gradient elution procedure was as follows: the mobile phase of 0-0.3 min is a mixed solution of 70% of A phase and 30% of B phase, the mobile phase of 0.3-3.5 min is a mixed solution of 70% -5%A phase and 30-95% of B phase, the mobile phase of 3.5-5 min is a mixed solution of 5%A phase and 95% of B phase, the mobile phase of 5-5.1 min is a mixed solution of 5% -70% of A phase and 95-30% of B phase, and the mobile phase of 5.1-8 min is a mixed solution of 70% of A phase and 30% of B phase.
In a preferred embodiment, in step S3, the LC-MS/MS measurement process mass spectrometry conditions include: a Dionex Ultimate3000/TSQ QUANTIVA ultra-high performance liquid chromatography mass spectrometer is adopted; the ion source is ESI-; the ion source voltage is 2800V; the temperature of the ion transmission tube is 350 ℃; the needle temperature was 300 ℃.
In a preferred embodiment, the tea leaf is at least one of oolong tea, black tea, green tea, black tea, white tea, brick tea, yellow tea and substitute tea.
In a preferred embodiment, the grass bud daub employs as its parent ion two isotopic ion peaks of 222.9 and 224.9.
The invention has the beneficial effects that:
(1) The invention provides a synchronous detection method of coumarone, dicamba, penta-nitrophenol, indomethacin and penconazole in tea, which comprises the steps of firstly adopting a mixed solution of water, formic acid and acetonitrile to perform vortex mixing extraction on a tea sample to be detected, adding sodium chloride to perform vortex mixing uniformly, performing high-speed centrifugation, adding anhydrous magnesium sulfate, GCB and C18 powder into the obtained supernatant to perform vortex mixing purification, and carrying out vortex mixing purification on the tea to be detected in the pretreatment process of the sampleThe ratio of the sample to water, formic acid, acetonitrile and sodium chloride is controlled to be 1g (5-7.5) mL (0.10-0.15) mL (10-15) mL (2-3) g, and the ratio of the tea sample to be tested to anhydrous magnesium sulfate, GCB and C18 powder is controlled to be 1g (600-900) mg (200-300) mg (100-150) mg; through the specific sample pretreatment mode, impurities affecting the test result in the sample, such as pigments and polysaccharides in tea, can be effectively removed, and only target products are reserved. The detection method provided by the invention can be used for simultaneously detecting 5 pesticides, namely coumarone, dicamba, pentanitrophenol, fenpyroxim and penconazole, wherein the instrument detection limit of the 5 pesticides is 0.1-0.8 ng/mL, the method detection limit is 0.1-0.8 mug/kg, and the correlation coefficient R of the 5 pesticides in the concentration range of 2-50 ng/mL 2 Is more than or equal to 0.999, and has good linear relation. The detection method provided by the invention has the advantages of rapidness, simplicity, convenience, high accuracy and high sensitivity, is favorable for qualitative and quantitative determination, and is easy to popularize and use.
(2) According to analysis of chemical structural formulas of 5 pesticides in the invention, couchgrass and grass bud aversion are chloridized acid pesticides, and pentatriclopyr, fenpyroxim and penconazole are phenol-bearing acid pesticides, and all the 5 compounds can provide protons, so that one proton is easily lost and negatively charged. Therefore, the invention preferably adopts ESI negative mode (ESI-) to realize synchronous detection of the 5 compounds, thereby improving detection efficiency.
(3) The grass bud is trichlorobenzoic acid, and because of three chlorine atoms on the structure, 223, 225, 227 and 229 isotope ion peaks can be generated in ESI negative mode, and the abundance ratio is 27:27:9:1, therefore, the invention prefers 222.9 and 224.9 ion peaks with larger abundance to be used as parent ions. Because of the special structure of the grass bud, after collision energy is applied, after parent ions lose one molecule of carboxylate radicals, a trichlorobenzene ring structure is remained, and the chemical structure is stable and difficult to break, so that only one trichlorobenzene ring fragment is obtained in fragment ions of the grass bud. According to the invention, by utilizing the difference of molecular weight of the chlorine atom isotopes, 178.8 fragment ions generated by the parent ion with mass-to-charge ratio of 222.9 are preferably used as quantitative ions, and 180.9 fragment ions generated by the parent ion with mass-to-charge ratio of 224.9 are used as qualitative ions, so that the accurate qualitative and quantitative detection of the grass bud daub is realized.
(4) According to the invention, 5 pesticides including coumarone, dicamba, pentanitrophenol, chlorphenol and phenol are measured by adopting a liquid chromatography-tandem mass spectrometry method, derivatization treatment is not needed for a tea sample to be measured, the sample pretreatment experimental step is simplified, a large amount of organic solvents such as methylene dichloride and the like are avoided in the sample pretreatment process, the personal safety of experimenters is improved, and the environmental protection is realized.
(5) During ESI negative mode analysis, formic acid can inhibit ionization efficiency of parent ions and reduce detection sensitivity, but can improve pH value of liquid phase mobile phase, so that retention performance of the compound on chromatographic column is changed. In the invention, when 5 pesticides including coumarone, dicamba, pentanitrophenol, fenpyroxim and penconazole are detected by adopting an ESI negative mode, a formic acid aqueous solution with the volume ratio of 0.02% v/v is added into a mobile phase to serve as a phase A. The 5 pesticides obtained through the test have reasonable retention time, good separation degree, sharp peak shape, symmetry and narrow peak, can greatly improve the peak shape of the target object, ensure that the sensitivity of the target object meets the detection requirement, can be better distinguished from other impurity peaks, and improve the accuracy and sensitivity of quantification and qualitative.
(6) The invention adopts the matrix standard curve external standard method, can effectively eliminate the matrix effect brought by the tea matrix, and effectively correct the recovery rate, so that the experimental result has higher accuracy and sensitivity.
Drawings
FIG. 1 is a standard graph of a standard sample of a couchgrass substrate;
FIG. 2 is a standard graph of a standard sample of a grass bud aversion matrix;
FIG. 3 is a standard graph of a standard sample of a pentanitrophenol matrix;
FIG. 4 is a standard graph of a standard sample of a reference matrix of the acarid-eliminating phenol;
FIG. 5 is a standard graph of a standard sample of a reference matrix of penconazole;
FIG. 6 (a) is an ion flow diagram of the extraction of 2ng/mL of coumarone, (b) 2ng/mL of dicamba, (c) 2ng/mL of pentanitol, (d) 2ng/mL of indomethacin, and (e) 2ng/mL of penconazole;
FIG. 7 (a) is an ion flow chart of the extraction of 10ng/mL of coumarone, (b) 10ng/mL of dicamba, (c) 10ng/mL of pentanitol, (d) 10ng/mL of indomethacin and (e) 10ng/mL of penconazole when mobile phase A is pure water;
FIG. 8 is an extract ion flowsheet of 10ng/mL coumarone, (b) 10ng/mL dicamba, (c) 10ng/mL pentanitol, (d) 10ng/mL indomethacin and (e) 10ng/mL penconazole in mobile phase A phase with 0.02% formic acid added.
Detailed Description
The present invention will be described in detail by examples.
(1) The reagents and medicines involved in the examples and comparative examples of the present invention are as follows:
standard couchgrass (purity 99.9%, bePure); grass bud daub standard (purity 99.3%, bePure); pentanitrophenol standard (purity 99.9%, bePure); the reference product of the fenpyroximate (purity 99.9%, bePure); standard mycophenolic (99.5% purity, bePure); methanol (chromatographic purity, epleren, sweden); formic acid (mass spectrometry grade, ACS chemistry in the united states); sodium chloride (superior purity, ridge science); anhydrous magnesium sulfate (analytically pure, schwann science); GCB, graphitized carbon black adsorbent (120-400 mesh, shanghai An Spectrometry laboratory technologies Co., ltd.); c18 powder (40-63 μm, shanghai An Spectrum laboratory technology Co., ltd.); water (primary water according to GB/T6682-2008).
(2) The experimental apparatus involved in the examples and comparative examples of the present invention is as follows:
waters BEH C18 (2.1 mm. Times.100 mm,1.7 μm, waters Co.); dionex Ultimate3000/TSQ QUANTIVA ultra performance liquid chromatography mass spectrometer (Thermo company, U.S.A.); MTV-100 multitube vortex mixer (Beijing Jin Yangmo, science and technology Co.); IKA MS3 Digital vortex mixer (xiaomen risi scientific instruments limited); ke Ruifeng ultrapure water system (Sichuan De Lishi technology Co., ltd.); GL-20C-II high-speed refrigerated centrifuge (Shanghai Anting scientific instruments Co.); KQ-600DE type digital controlled ultrasonic cleaner (Kunshan ultrasonic instruments Co., ltd.); autoEVA-60 full-automatic parallel concentrator (Ruiaceae group (Xiamen Co., ltd.); 0.22 μm polytetrafluoroethylene needle filter (Tianjin laboratory equipment Co., ltd.).
Example 1
S1: sample pretreatment
Weighing 2g of tea leaf sample to be tested (accurate to 0.01 g) in a 50mL centrifuge tube, respectively adding 10mL of water, 0.2mL of formic acid and 20mL of acetonitrile solution, performing vortex mixing and extraction for 10min, adding 4g of sodium chloride, performing vortex mixing for 30s, centrifuging for 5min at a rotating speed of 10000rpm, and standing for layering; transferring the supernatant into a 50mL centrifuge tube, adding 1200mg anhydrous magnesium sulfate, 400mg GCB and 200mg C18 powder, fully vortex mixing and purifying for 60s, centrifuging for 5min at the rotating speed of 15000rpm, standing and layering; accurately transferring 10mL of supernatant, blowing in water bath nitrogen at 45 ℃ until the supernatant is nearly dry, adding 1mL of 30% v/v methanol aqueous solution for re-dissolution and uniform mixing, and finally filtering by a 0.22 mu m organic microporous filter membrane to obtain a sample solution to be detected.
S2: preparing standard solution
(1) Preparing a standard product: respectively dissolving standard substances of the grass bud dicamba, the pentanitrophenol, the fenpyroxim and the penconazole in acetonitrile to prepare a standard stock solution with the concentration of 1.0mg/mL, diluting the standard substance of the grass bud dicamba in acetonitrile to prepare a standard stock solution with the concentration of 100 mug/mL, and diluting the standard stock solution with acetonitrile to prepare a mixed standard working solution with the concentration of 1.0 mug/mL;
(2) Preparing standard solution of matrix
Selecting tea samples with the contents of coumarone, dicamba, pentanitrophenol, fenpyroxim and penconazole lower than the detection limit of an experimental method as negative blank tea samples, performing sample pretreatment according to the step S1 to obtain a matrix blank solution, and preparing the standard working solution in the step (1) into a series of matrix mixed standard solutions with concentration gradients of 2ng/mL, 5ng/mL, 10ng/mL, 20ng/mL and 50ng/mL respectively by using the matrix blank solution.
S3: sample detection
Carrying out LC-MS/MS measurement on the mixed standard solution of the matrix of the coumarone, the dicamba, the penta-nitrophenol, the fenpyroximate and the virulent phenol in the step S2 to obtain a matrix standard working curve; and (3) carrying out LC-MS/MS determination on the sample solution to be detected in the step (S1), quantifying by adopting a matrix standard curve external standard method, and comparing the obtained detection curve with a standard working curve to obtain the contents of coumarone, dicamba, pentanitrophenol, indomethacin and penconazole in the tea sample to be detected.
In the LC-MS/MS assay, the liquid chromatography conditions include: the column was a Waters BEH C18 (2.1 mm. Times.150 mm,1.7 μm); the column temperature is 35 ℃; the flow rate is 0.30mL/min; the sample injection amount is 5 mu L; the mobile phase was eluted with a gradient with 0.02% v/v formic acid in water as phase A and methanol as phase B and the procedure was as follows: the mobile phase of 0-0.3 min is a mixed solution of 70% of A phase and 30% of B phase, the mobile phase of 0.3-3.5 min is a mixed solution of 70% -5%A phase and 30-95% of B phase, the proportion gradient between the A phase and the B phase is linear change, the mobile phase of 3.5-5 min is a mixed solution of 5%A phase and 95% of B phase, the mobile phase of 5-5.1 min is a mixed solution of 5% -70% of A phase and 95-30% of B phase, the proportion gradient between the A phase and the B phase is linear change, and the mobile phase of 5.1-8 min is a mixed solution of 70% of A phase and 30% of B phase.
In the LC-MS/MS detection process, mass spectrum conditions include: a Dionex Ultimate3000/TSQ QUANTIVA ultra-high performance liquid chromatography mass spectrometer is adopted; the ion source is ESI-; the ion source voltage is 2800V; the temperature of the ion transmission tube is 350 ℃; the temperature of the spray needle is 300 ℃; the mass spectrometry information is specifically shown in table 1.
TABLE 1
Quantitative ion pairs are shown in Table 1
The corresponding concentrations at 10 times of the signal-to-noise ratio are selected as the detection limit of the target object, the results obtained by correlation coefficients of 5 pesticide standard curves of coumarone, dicamba, pentatriclopyr, fenpyroxim and penconazole are shown in table 2 and figures 1-5, and the test results of the ion extraction flow diagram of coumarone, dicamba, pentatriclopyr, fenpyroxim and penconazole with the concentration of 2ng/mL under the detection conditions are shown in figure 6. The results show that the 5 pesticides have good linear relationship in the mass concentration range of 2-50 ng/mLCorrelation coefficient R 2 The detection limit of the instrument is 0.9990-0.9996, and the detection limit of the instrument is 0.1-0.8 ng/mL, and the detection limit of the method is 0.1-0.8 mug/kg. Therefore, the detection method provided by the invention has good accuracy and high sensitivity, and the detection limit meets the requirement (0.01 mg/kg) of the temporary maximum residue limit value specified by the current national standard (GB 2763-2021), so that the detection requirements of the pesticide residues of couchgrass, dicamba, pentanitrophenol, fenpyroxim and penconazole in tea can be met.
TABLE 2
Comparative example 1
In the sample detection, an aqueous solution of formic acid of 0.02% v/v was not added as phase A (i.e., pure water was directly used as phase A) and the other conditions were the same as in example 1, except that the test results were as shown in FIG. 7 and FIG. 8. It is known that the addition of formic acid suppresses ionization efficiency of parent ions and decreases detection sensitivity when performing ESI negative mode analysis, but can improve pH of a liquid phase mobile phase and change retention performance of a compound on a chromatographic column. From the results of fig. 7 and 8, it is understood that when pure water is used as phase a, the retention effect of the 5 pesticides obtained by the test is poor, and peak broadening and even peak cracking occur to different degrees. However, when the sample is detected, formic acid with the volume ratio of 0.02% v/v is added into pure water as phase A, and 5 pesticides obtained by testing have reasonable retention time, good separation degree, sharp peak shape, symmetry and narrow peak. Therefore, formic acid with the volume ratio of 0.02% v/v is added into pure water as phase A, so that the peak shape of a target object can be greatly improved, the sensitivity of the target object can be ensured to meet the detection requirement, the target object can be better distinguished from other impurity peaks, and the accuracy and the sensitivity of quantification and qualitative are improved. Thus, the present invention selects an aqueous formic acid solution at a concentration of 0.02% v/v as phase A and methanol as phase B as the mobile phase.
Test case
The commercial Tieguanyin, jinjunmei and Pu' er tea were used as test subjects, 5 pesticide standard solutions of couchgrass, paravom, pentaniferous phenol, indomethacin and penconazole were added to negative samples and marked 5 μg/kg, 20 μg/kg and 40 μg/kg respectively, and parallel tests (n=6) were performed to determine recovery and Relative Standard Deviation (RSD) as shown in Table 3. From the experimental data in table 3, the results show that the recovery rate of 5 pesticides under three standard concentration conditions is 60.2% -91.1%, and the relative standard deviation RSD (n=6) is 2.6% -8.8%. The measurement result meets the requirements of GB/T27404-2008 "laboratory quality control Specification food physicochemical detection".
TABLE 3 Table 3
By applying the synchronous detection method of the coumarone, the dicamba, the penta-nitrophenol, the indomethacin and the penconazole in the tea provided by the invention, 100 batches of commercial tea are detected, and the result shows that all samples do not detect the 5 pesticide residues.
Although embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives, and variations may be made in the above embodiments by those skilled in the art without departing from the spirit and principles of the invention.
Claims (7)
1. A synchronous detection method for couchgrass, dicamba, penta-nitrophenol, fenpyroxim and penconazole in tea leaves is characterized by comprising the following steps:
s1: sample pretreatment
Weighing a proper amount of tea samples to be tested, putting the tea samples into a centrifuge tube, performing vortex mixing extraction by adopting a mixed solution of water, formic acid and acetonitrile, adding sodium chloride, performing vortex mixing, and centrifuging to obtain a product I; adding anhydrous magnesium sulfate, GCB and C18 powder into the supernatant, vortex mixing, purifying and centrifuging II; collecting supernatant, blowing nitrogen to dryness at 35-45 ℃, adding 25-35% v/v methanol aqueous solution for re-dissolution, and finally filtering with a 0.1-0.3 mu m filter membrane to obtain a sample solution to be detected, and reserving for LC-MS/MS detection; wherein the ratio of the tea sample to be tested to water, formic acid, acetonitrile and sodium chloride is 1g (5-7.5) mL (0.10-0.15) mL (10-15) mL (2-3) g; the ratio of the tea leaf sample to be tested to anhydrous magnesium sulfate, GCB and C18 powder is 1g (600-900 mg) (200-300 mg) (100-150 mg);
s2: preparing standard solution of matrix
Taking a negative blank tea sample, and performing sample pretreatment according to the step S1 to obtain a matrix blank solution; dissolving standard substances of coumarone, dicamba, pentanitrophenol, fenpyroxim and penconazole in a solvent, and preparing a series of matrix mixed standard solutions with concentration gradients of 2-50 ng/mL respectively by using a matrix blank solution;
s3: sample detection
Carrying out LC-MS/MS measurement on the mixed standard solution of the matrix of the coumarone, the dicamba, the penta-nitrophenol, the fenpyroximate and the virulent phenol in the step S2 to obtain a matrix standard working curve; carrying out LC-MS/MS determination on the sample solution to be detected in the step S1, quantifying by adopting a matrix standard curve external standard method, and comparing the obtained detection curve with a standard working curve to obtain the contents of coumarone, dicamba, pentanitrophenol, indomethacin and penconazole in the tea sample to be detected;
in step S3, the LC-MS/MS measurement process includes: the chromatographic column is Waters BEH C18; the column temperature is 35 ℃; the flow rate is 0.30mL/min; the sample injection amount is 5 mu L; the mobile phase was eluted with a gradient using aqueous formic acid at a concentration of 0.02% v/v as phase A and methanol as phase B and the gradient elution procedure was as follows: the mobile phase of 0-0.3 min is a mixed solution of 70% of A phase and 30% of B phase, the mobile phase of 0.3-3.5 min is a mixed solution of 70% -5%A phase and 30-95% of B phase, the mobile phase of 3.5-5 min is a mixed solution of 5%A phase and 95% of B phase, the mobile phase of 5-5.1 min is a mixed solution of 5% -70% of A phase and 95-30% of B phase, and the mobile phase of 5.1-8 min is a mixed solution of 70% of A phase and 30% of B phase.
2. The method for synchronously detecting coumarone, dicamba, penta-nitrophenol, indomethacin and penconazole in tea leaves according to claim 1, wherein in the step S1, the condition of vortex mixing extraction is vortex for 10-15 min; the vortex mixing condition is vortex 30-60 s; the vortex mixing purification condition is vortex 60-90 s.
3. The method for synchronously detecting coumarone, dicamba, penta-nitrophenol, tebufenpyrad and penconazole in tea leaves according to claim 1, wherein in step S1, the condition of centrifugation I comprises centrifugation speed of 10000-20000 rpm for 5-10 min; the conditions of the centrifugal II comprise centrifugal rotation speed of 10000-20000 rpm and centrifugal time of 5-10 min.
4. The method for simultaneous detection of coumarone, dicamba, penta-nitrophenol, indomethacin and penconazole in tea leaves according to claim 1, wherein in step S1, the filter membrane is an organic filter membrane, and the pore size of the filter membrane is 0.22 μm.
5. The method for simultaneous detection of coumarone, dicamba, pentanifloric, indomethacin and penconazole in tea leaves according to claim 1, wherein in step S3, mass spectrometry conditions in the LC-MS/MS measurement process comprise: a Dionex Ultimate3000/TSQ QUANTIVA ultra-high performance liquid chromatography mass spectrometer is adopted; the ion source is ESI-; the ion source voltage is 2800V; the temperature of the ion transmission tube is 350 ℃; the needle temperature was 300 ℃.
6. The method for simultaneous detection of couchgrass, dicamba, pentanifol, indomethacin and penconazole in tea leaves according to claim 1, wherein said tea leaves are at least one of oolong tea, black tea, green tea, black tea, white tea, brick tea, yellow tea and substituted tea.
7. The method for simultaneous detection of coumarone, dicamba, pentanifol, indoxacarb and penconazole in tea leaves according to claim 5, wherein said dicamba uses two isotopic ion peaks 222.9 and 224.9 as parent ions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210522528.XA CN114910588B (en) | 2022-05-13 | 2022-05-13 | Synchronous detection method for couchgrass, dicamba, penta-nitrophenol, fenpyroxim and penconazole in tea |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210522528.XA CN114910588B (en) | 2022-05-13 | 2022-05-13 | Synchronous detection method for couchgrass, dicamba, penta-nitrophenol, fenpyroxim and penconazole in tea |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114910588A CN114910588A (en) | 2022-08-16 |
| CN114910588B true CN114910588B (en) | 2023-10-10 |
Family
ID=82765976
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210522528.XA Active CN114910588B (en) | 2022-05-13 | 2022-05-13 | Synchronous detection method for couchgrass, dicamba, penta-nitrophenol, fenpyroxim and penconazole in tea |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114910588B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108152395A (en) * | 2017-12-12 | 2018-06-12 | 大连理创科技有限公司 | A kind of method for measuring pesticide residue in agricultural products |
| CN109212070A (en) * | 2018-09-24 | 2019-01-15 | 丁立平 | Gas chromatography that is a kind of while measuring four kinds of benzoic acid herbicides in cereal |
| CN111965287A (en) * | 2020-08-26 | 2020-11-20 | 浙江宏盛科技信息服务有限公司 | Method for determining 5 nitrophenol compounds in soil based on ultrahigh pressure high performance liquid chromatography tandem mass spectrometry |
-
2022
- 2022-05-13 CN CN202210522528.XA patent/CN114910588B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108152395A (en) * | 2017-12-12 | 2018-06-12 | 大连理创科技有限公司 | A kind of method for measuring pesticide residue in agricultural products |
| CN109212070A (en) * | 2018-09-24 | 2019-01-15 | 丁立平 | Gas chromatography that is a kind of while measuring four kinds of benzoic acid herbicides in cereal |
| CN111965287A (en) * | 2020-08-26 | 2020-11-20 | 浙江宏盛科技信息服务有限公司 | Method for determining 5 nitrophenol compounds in soil based on ultrahigh pressure high performance liquid chromatography tandem mass spectrometry |
Non-Patent Citations (3)
| Title |
|---|
| Recent Modifications and Validation of QuEChERS-dSPE Coupled to LC-MS and GC-MS Instruments for Determination of Pesticide/Agrochemical Residues in Fruits and Vegetables: Review;Abubakar Lawal et al.;Journal of Chromatographic Science;第56卷(第7期);第656-669页 * |
| 液相色谱串联质谱法测定蔬菜水果中六种农药残留;张伟彪等;农业与技术;第39卷(第13期);第24-26页 * |
| 衍生气相色谱-质谱法测定水中氯代酸性除草剂;张莉等;分析试验室;第29卷(第3期);第19-22页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114910588A (en) | 2022-08-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108663471B (en) | Method for determining contents of multiple endocrine disruptors in estuary sediments | |
| CN105548412B (en) | Method that is a kind of while measuring 5 kinds of aminoglycoside medicaments residual quantities in food | |
| CN107884493B (en) | Method for analyzing short-chain chlorinated paraffin in environmental sample by using full-two-dimensional gas chromatography-time-of-flight mass spectrometry | |
| CN106124674B (en) | A kind of pre-treating method of quick measurement Pesticide Residues in Tea and quantitative analysis method | |
| CN115184497B (en) | Method for determining content of 2, 4-epibrassinolide in dendrobium candidum | |
| CN109828071B (en) | Method for simultaneously detecting 9 water-infused drug residues in pork | |
| CN103217498B (en) | Method for detecting dicyandiamide in milk powder with LC-MS (liquid chromatography/mass spectrometry) and sample preparation method | |
| CN114910588B (en) | Synchronous detection method for couchgrass, dicamba, penta-nitrophenol, fenpyroxim and penconazole in tea | |
| CN103344732A (en) | Method for simultaneous detection of ofloxacin and sarafloxacin in water body | |
| CN110887922A (en) | Method for rapidly detecting residual quantity of cyromazine in vegetables | |
| CN103207256B (en) | Method for detecting floridoside and isofloridoside contents in porphyra haitanensis | |
| CN112903836B (en) | Method for determining isopropyl-beta-D-thiogalactopyranoside in-vitro cultured bear gall powder | |
| CN111337610B (en) | Method for detecting trace estrogen, nonyl phenol and bisphenol A in complex environment matrix | |
| CN114705785B (en) | Method for detecting chlorophthalic acid in vegetable oil | |
| CN111220722B (en) | Method for simultaneously determining 8 p-hydroxybenzoate compounds in soil | |
| CN113325107A (en) | Method for high-efficiency qualitative and quantitative analysis of plant metabolic modification group by using LC-MS/MS | |
| CN108519454B (en) | Pretreatment method for measuring various pesticide residues in tea and detection method thereof | |
| CN111337611A (en) | Method for detecting malachite green, leucomalachite green, crystal violet and leucocyte crystal violet in aquatic products | |
| CN113311085B (en) | Method for measuring content of chlorogenic acid and linarin in wild chrysanthemum granules | |
| CN105116091B (en) | Method for measuring dibromochloropropane residues in fruits and vegetables by GC-NCI-MS | |
| CN109324140A (en) | Ribosylzeatin Solid Phase Extraction-liquid chromatography-tandem mass spectrometry measuring method in a kind of tobacco leaf | |
| CN115015446B (en) | Method for simultaneously measuring L-theanine, caffeine, tea polyphenol and hexadecanoic acid in green tea | |
| CN114778746B (en) | Method for detecting 9 alkaloids in blood by liquid chromatography-tandem mass spectrometry and application | |
| CN113640401B (en) | Method for detecting aristolochic acid in soil | |
| CN111879879B (en) | Method for detecting methamidophos and octachlorodipropyl ether in plant food |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |