Method for determining residual quantity of diflufenican in plant-derived food

Abstract

The invention relates to a method for determining the residual quantity of diflufenican in plant-derived food. The method comprises the following specific steps: (1) drawing a standard curve; (2) sample extraction; (3) purifying; (4) determining the recovery rate; (5) determining the content of the diflufenican in the sample; according to the method for measuring the diflufenican residual quantity in the plant-derived food, acetonitrile is used for extraction, an extracting solution is purified by a solid-phase extraction column and then measured on a machine, an ultra-high performance liquid chromatography-tandem mass spectrometry multi-reaction monitoring mode is adopted, high selectivity and sensitivity are achieved, the matrix effect and impurity interference are effectively reduced, and the method is suitable for large-scale industrial production. The method can directly adopt a solvent standard curve for quantification, has high accuracy and precision, and provides technical support for further perfecting and supplementing diflufenican dietary intake and risk data of residents and formulating maximum residual limit.

Description

Technical Field

[0001] The present invention belongs to the field of modern food, and particularly relates to a method for determining the residue amount of picolinafen in phytogenic foods. Background Art

[0002] Picolinafen belongs to a new type of pyridinecarboxamide herbicide, which is mainly used for controlling annual broad-leaved weeds in crop fields. With the popularization and application of picolinafen, people pay more and more attention to the dietary intake risk and risk control of picolinafen. Therefore, it is becoming more and more urgent to study and formulate the residue limit standard of picolinafen. However, there is currently a lack of a residue analysis method for picolinafen in phytogenic foods with high sensitivity and low matrix effect. Solving the residue detection method of picolinafen in phytogenic foods is the premise and basis for formulating the limit standard and studying the dietary intake risk. Zhang Yanqing et al. developed a high-performance liquid chromatography analysis method for 20% picolinafen suspension concentrate. This method is applicable to the quality control field of pesticide formulations and is not applicable in the residue analysis field due to its low method sensitivity and weak anti-matrix interference. Luo Qiao et al. developed a gas chromatography-mass spectrometry method for determining picolinafen in plasma. This method has low sensitivity and high matrix effect, requires the preparation of matrix-matched standard solutions, increases the detection process and complexity, and this method is applicable to plasma and is not applicable to the determination of picolinafen in phytogenic foods. Summary of the Invention

[0003] The purpose of the present invention is to develop an ultra-high performance liquid chromatography tandem mass spectrometry method with high sensitivity and low matrix effect, which can directly quantify using a solvent standard curve to determine the residue amount of picolinafen in phytogenic foods, filling the blank.

[0004] The present invention is achieved through the following technical solutions: A method for determining the residue amount of picolinafen in phytogenic foods, characterized by including the following specific steps: (1). Standard curve drawing Absorb 0.5 mL of 1000 mg / L picolinafen standard solution into a 50 mL volumetric flask, dilute and make up the volume with methanol to obtain a 10 mg / L picolinafen solution. Gradually dilute the 10 mg / L picolinafen solution with methanol to obtain a picolinafen standard working solution of 0.002 mg / L to 0.1 mg / L, and perform ultra-high performance liquid chromatography tandem mass spectrometry analysis and detection. The linear correlation is good. Perform regression with the concentration as the abscissa and the peak area as the ordinate to obtain the picolinafen standard curve; (2). Sample extraction Weigh the pulverized sample to be tested, add acetonitrile and water, vortex for 3 min, then centrifuge at room temperature for 3 min and freeze for 30 min to separate the acetonitrile phase and the water phase; (3). Purification Absorb the upper layer of acetonitrile solution to be purified and directly pass it through a solid-phase extraction cartridge, collect the filtrate for testing; (4). Recovery rate determination Weigh the blank sample after pulverization, add the flufenican standard solution at the addition amounts of 0.002 mg / kg, 0.01 mg / kg, and 0.1 mg / kg respectively, repeat steps (2) and (3), conduct ultra-high performance liquid chromatography-tandem mass spectrometry analysis, compare with the flufenican standard curve in step (1), calculate, obtain the measured value of flufenican, and calculate the recovery rate; (5). Determination of the content of flufenican in the sample Compare and calculate the content of flufenican detected in step (3) with the flufenican standard curve in step (1) to obtain the actual content of flufenican in the sample to be tested; In the above step (3), absorb 3 - 5 mL of the acetonitrile solution to be purified, and the filler of the solid-phase extraction cartridge used is one of diphenylmethane diisocyanate-polyethylene glycol, diphenylmethane diisocyanate-polypropylene glycol, diphenylmethane diisocyanate-polyoxytetramethylene glycol, tolylene diisocyanate-polyethylene glycol, tolylene diisocyanate-polypropylene glycol, tolylene diisocyanate-polyoxytetramethylene glycol, polymethylene diphenyl diisocyanate-polyethylene glycol, polymethylene diphenyl diisocyanate-polypropylene glycol, polymethylene diphenyl diisocyanate-polyoxytetramethylene glycol; In steps (1) and (4) above, the liquid chromatography conditions are as follows: chromatographic column: ZORBAX SB C18 2.1×50 mm×3.5μm; column temperature 30°C; mobile phase A: 0.1% formic acid water, mobile phase B: methanol; mobile phase gradient: 10%B from 0 to 1.0 min, 10%B - 95%B from 1.0 to 6.0 min, 95%B from 6.0 to 9.0 min, 10%B at 9.5 min; flow rate 0.4 mL / min; injection volume 1μL; the mass spectrometry conditions are atmospheric pressure chemical ionization positive ion mode; desolvation tube temperature 200°C; heating module temperature 200°C; ion source temperature 350°C; drying gas flow rate 5 L / min, nebulizing gas flow rate 3 L / min, collision gas pressure 230 kPa; scanning mode is multiple reaction monitoring; the quantitative ion pair of flufenican: 377 / 238, qualitative ion pairs: 377 / 266 and 377 / 359.

[0005] Preferably, in step (1) above, the specific concentration range with good linear correlation is: flufenican has good linearity between 0.002 mg / L and 0.1 mg / L.

[0006] Furthermore, in step (1) above, the standard curve of flufenican is: Y = 116209646X - 51267, and the correlation coefficient r = 0.9999.

[0007] Preferably, in step (2), the mass of the sample to be measured is 2.0 - 10.0 g, the added water is 5 - 10 mL, the added acetonitrile is 10 - 20 mL, and the freezing temperature is -10°C to -20°C.

[0008] The method for detecting the residue of flufenacet in phytogenic foods uses a mixture of acetonitrile and water for extraction. The extraction solution is frozen to promote the stratification of acetonitrile and water, reducing the impurities dissolved in the acetonitrile layer. Further purification by a solid-phase extraction column reduces impurities even more. Through two-step impurity removal and using the positive mode of atmospheric pressure chemical ionization source in ultra-high performance liquid chromatography tandem mass spectrometry, the matrix effect is greatly reduced, and it has high selectivity and sensitivity. This enables the method to directly quantify using a solvent standard curve, with high accuracy and precision, providing technical support for further improving and supplementing the dietary intake and risk data of flufenacet for residents and formulating the maximum residue limit. Description of the Drawings

[0009] Figure 1 : MRM chromatogram of ultra-high performance liquid chromatography tandem mass spectrometry of the sample added with 0.01 mg / kg flufenacet standard solution in the embodiment of the present invention. Detailed Embodiments

[0010] The following refers to the drawings to give the detailed embodiments of the present invention to further illustrate the detection method of the present invention.

[0011] Example 1 1. Main instrument equipment and materials Shimadzu LC / MS 8040; multi-tube vortex mixer (Detelogy); LUXIANGYI centrifuge TG 16; Sartorius BL610 electronic analytical balance; Merck Milli-Q ultrapure water system; solid-phase extraction column (150mg, 6mL); methanol, acetonitrile, and formic acid are all chromatographically pure.

[0012] 2. Determination method (1). Drawing of the standard curve Absorb 0.5 mL of 1000 mg / L flufenacet standard solution into a 50 mL volumetric flask, dilute and make up the volume with methanol to obtain a 10 mg / L flufenacet solution. Gradually dilute the 10 mg / L flufenacet solution with methanol to obtain 0.002mg / L, 0.005 mg / L, 0.01 mg / L, 0.05 mg / L, 0.1 mg / L flufenacet standard working solutions, and perform ultra-high performance liquid chromatography tandem mass spectrometry analysis and detection; use the concentration as the abscissa and the peak area as the ordinate for regression to obtain the flufenacet standard curve: Y = 116209646X - 51267, and the correlation coefficient r = 0.9999; (2). Sample extraction Weigh 2.0 g of crushed wheat, add 10 mL of water and 20 mL of acetonitrile, vortex for 3 min, centrifuge for 3 min, and freeze at -10 °C for 30 min to separate the acetonitrile phase and the water phase; (3). Purification Pipette 3 mL of the acetonitrile solution to be purified directly through a polydiphenylmethane diisocyanate - polyethylene glycol solid-phase extraction column, collect the filtrate for further testing; (4). Recovery rate determination Weigh 15 portions of 2.0 g of blank wheat samples after crushing, add at three levels of 0.002 mg / kg, 0.01 mg / kg, and 0.1 mg / kg respectively, repeat steps (2) and (3), repeat each addition concentration 5 times, perform ultra-high performance liquid chromatography tandem mass spectrometry analysis, obtain the determined values of flufenican, and calculate the recovery rate. The data is shown in Table 1; (5). Determination of the flufenican content in the sample Compare and calculate the flufenican content detected in step (3) with the flufenican standard curve in step (1) to obtain the actual residual flufenican content in the sample to be tested.

[0013] Among them, the instrument conditions for ultra-high performance liquid chromatography tandem mass spectrometry are set as follows: Liquid chromatography conditions: Chromatographic column: ZORBAX SB C18 2.1×50 mm×3.5 μm; column temperature 30 °C; mobile phase A: 0.1% formic acid in water, mobile phase B: methanol; mobile phase gradient: 10% B from 0 to 1.0 min, 10% B - 95% B from 1.0 to 6.0 min, 95% B from 6.0 to 9.0 min, 10% B at 9.5 min; flow rate 0.4 mL / min; injection volume 1 μL; Mass spectrometry conditions: Atmospheric pressure chemical ionization positive ion mode; desolvation tube temperature 200 °C; heating module temperature 200 °C; ion source temperature 350 °C; drying gas flow rate 5 L / min, nebulizing gas flow rate 3 L / min, collision gas pressure 230 kPa; scanning mode: multiple reaction monitoring; Quantitative ion pair of flufenican: 377 / 238, qualitative ion pairs: 377 / 266 and 377 / 359.

[0014] Table 1 Recovery rate and precision of flufenican

[0015] Detect and analyze the flufenican residue in 30 randomly selected wheat samples according to the above detection steps, and the residue amount is <0.002 mg / kg - 0.01 mg / kg.

[0016] Example 2 1. Main instruments and equipment (same as Example 1) 2. Determination method (1) Drawing of standard curve (same as Example 1) (2) Sample extraction Weigh 5.0 g of crushed corn sample, add 8 mL of water and 15 mL of acetonitrile, vortex for 3 min, centrifuge for 3 min, and freeze at -15 °C for 30 min to separate the acetonitrile phase and the water phase; (3) Purification Pipette 5 mL of the acetonitrile solution to be purified directly through a diphenylmethane diisocyanate - polypropylene glycol solid-phase extraction column, collect the filtrate for later measurement; (4) Recovery rate determination Weigh 15 portions of 5.0 g of crushed corn samples, add at three levels of 0.002 mg / kg, 0.01 mg / kg, and 0.1 mg / kg respectively, repeat steps (2) and (3), repeat 5 times for each added concentration, perform liquid chromatography - tandem mass spectrometry analysis, obtain the measured value of flufenican, and calculate the recovery rate. The data are shown in Table 2; (5) Determination of flufenican content in the sample Compare and calculate the flufenican content detected in step (3) with the flufenican standard curve in step (1) to obtain the actual residual flufenican content in the sample to be measured.

[0017] Among them, the instrument conditions for ultra-high performance liquid chromatography - tandem mass spectrometry are the same as those in Example 1.

[0018] Table 2 Recovery rate and precision of flufenican

[0019] According to the above detection steps, the flufenican residue in 10 random corn samples was detected and analyzed, and the residue was all < 0.002 mg / kg.

[0020] Example 3 1. Main instruments and equipment (same as Example 1) 2. Determination method (1) Drawing of standard curve (same as Example 1) (2) Sample extraction Weigh 10.0 g of crushed celery sample, add 5 mL of water and 10 mL of acetonitrile, vortex for 3 min, centrifuge for 3 min, and freeze at -20 °C for 30 min to separate the acetonitrile phase and the water phase; (3) Purification Pipette 4 mL of the acetonitrile solution to be purified directly through a diphenylmethane diisocyanate - polytetrahydrofuran solid-phase extraction column, collect the filtrate for later measurement; (4). Recovery rate determination Weigh 15 portions of 10.0 g of crushed celery blank samples, and add them at three levels of 0.002 mg / kg, 0.01 mg / kg, and 0.1 mg / kg respectively. Repeat steps (2) and (3), with each addition concentration repeated 5 times, and conduct ultra-high performance liquid chromatography-tandem mass spectrometry analysis to obtain the measured values of flufenican, and calculate the recovery rate. The data are shown in Table 3; (5). Determination of flufenican content in samples Compare and calculate the flufenican content detected in step (3) with the flufenican standard curve in step (1) to obtain the actual residual flufenican content in the sample to be tested.

[0021] Among them, the instrument conditions for ultra-high performance liquid chromatography-tandem mass spectrometry are the same as those in Example 1.

[0022] Table 3 Recovery rate and precision of flufenican

[0023] Detect and analyze the residual amount of flufenican in 20 randomly selected celery samples according to the above detection steps, and the residual amount is all <0.002 mg / kg.

[0024] Example 4 1. Main instrument and equipment (same as in Example 1) 2. Determination method (1)Standard curve drawing (same as in Example 1) (2)Sample extraction Weigh 5.0 g of crushed pepper samples, add 5 mL of water and 10 mL of acetonitrile, vortex for 3 min, centrifuge for 3 min, and freeze at -18 °C for 30 min to separate the acetonitrile phase and the water phase; (3). Purification Absorb 5 mL of the acetonitrile solution to be purified and directly pass it through a poly-tolylene diisocyanate-polyethylene glycol solid-phase extraction column, and collect the filtrate for further testing; (4). Recovery rate determination Weigh 15 portions of 5.0 g of crushed pepper blank samples, and add them at three flufenican addition concentrations of 0.002 mg / kg, 0.01 mg / kg, and 0.1 mg / kg respectively. Repeat steps (2) and (3), with each addition concentration repeated 5 times, and conduct ultra-high performance liquid chromatography-tandem mass spectrometry analysis to obtain the measured values of flufenican, and calculate the recovery rate. The data are shown in Table 4; (5). Determination of flufenican content in samples Compare and calculate the flufenican content detected in step (3) with the flufenican standard curve in step (1) to obtain the actual residual flufenican content in the sample to be tested.

[0025] The instrument conditions of ultra-high performance liquid chromatography tandem mass spectrometry are the same as those in Example 1.

[0026] Table 4 Recovery and precision of fluazifop-butyl

[0027] According to the above detection steps, 20 random pepper samples were tested and analyzed for fluazifop residues, and the residues were all <0.002 mg / kg.

[0028] Example 5 1. Main instruments and equipment (same as Example 1) 2. Determination method (1) Drawing of standard curve (same as Example 1) (2) Sample extraction Weigh 8.0 g of crushed apple sample, add 8 mL of water and 20 mL of acetonitrile, vortex for 3 min, centrifuge for 3 min, and freeze at -12 °C for 30 min to separate the acetonitrile phase and the aqueous phase; (3) Purification 4 mL of the acetonitrile solution to be purified was directly passed through the poly(toluene diisocyanate)-polypropylene glycol) solid phase extraction column, and the filtrate was collected for testing; (4) Recovery rate determination Weigh 15 portions of 8.0 g of crushed apple blank samples, add three concentrations of fluazifop-butyl at 0.002 mg / kg, 0.01 mg / kg and 0.1 mg / kg, repeat steps (2) and (3), repeat each addition concentration 5 times, perform ultra-performance liquid chromatography tandem mass spectrometry analysis, obtain the fluazifop-butyl determination value, and calculate the recovery rate. The data are shown in Table 5. (5) Determination of fluazifop content in samples The content of fluazifop detected in step (3) is compared with the fluazifop standard curve in step (1) and calculated to obtain the actual residual fluazifop content in the sample to be tested.

[0029] The instrument conditions of ultra-high performance liquid chromatography tandem mass spectrometry are the same as those in Example 1.

[0030] Table 5 Recovery and precision of fluazifop-butyl

[0031] According to the above detection steps, 20 random apple samples were tested and analyzed for fluazifop residues, and the residues were all <0.002 mg / kg.

[0032] Example 6 1. Main instruments and equipment (same as Example 1) 2. Determination method (1) Standard curve plotting (same as Example 1) (2) Sample extraction Weigh 9.0 g of crushed citrus samples, add 9 mL of water and 18 mL of acetonitrile, vortex for 3 min, centrifuge for 3 min, and freeze at -16 °C for 30 min to separate the acetonitrile phase and the water phase; (3). Purification Pipette 3 mL of the acetonitrile solution to be purified directly through a polytoluene diisocyanate - polytetrahydrofuran solid-phase extraction column, collect the filtrate for further measurement; (4). Recovery rate determination Weigh 15 portions of 9.0 g of crushed citrus blank samples, add at three levels of 0.002 mg / kg, 0.01 mg / kg, and 0.1 mg / kg respectively, repeat steps (2) and (3), repeat 5 times for each added concentration, perform ultra-high performance liquid chromatography tandem mass spectrometry analysis, obtain the measured value of flufenican, and calculate the recovery rate. The data is shown in Table 6; (5). Determination of flufenican content in samples Compare and calculate the flufenican content detected in step (3) with the flufenican standard curve in step (1) to obtain the actual residual flufenican content in the sample to be measured.

[0033] Among them, the instrument conditions for ultra-high performance liquid chromatography tandem mass spectrometry are the same as those in Example 1.

[0034] Table 6 Recovery rate and precision of flufenican

[0035] According to the above detection steps, the flufenican residue in 20 randomly selected citrus samples was detected and analyzed, and the residue was all < 0.002 mg / kg.

[0036] Example 7 1. Main instrument and equipment (same as Example 1) 2. Determination method (1) Standard curve plotting (same as Example 1) (2) Sample extraction Weigh 10.0 g of crushed shiitake mushroom samples, add 10 mL of water and 20 mL of acetonitrile, vortex for 3 min, centrifuge for 3 min, and freeze at -18 °C for 30 min to separate the acetonitrile phase and the water phase; (3). Purification Pipette 4 mL of the acetonitrile solution to be purified directly through a polymethylene diphenyl diisocyanate - polyethylene glycol solid-phase extraction column, collect the filtrate for further measurement; (4). Recovery rate determination Weigh 15 portions of 10.0 g of crushed blank shiitake mushroom samples, add them at three levels of 0.002 mg / kg, 0.01 mg / kg, and 0.1 mg / kg respectively, repeat steps (2) and (3), repeat each addition concentration 5 times, conduct ultra-high performance liquid chromatography tandem mass spectrometry analysis, obtain the determination values of fluopyram, and calculate the recovery rates. The data are shown in Table 7; (5) Determination of the fluopyram content in the sample Compare and calculate the fluopyram content detected in step (3) with the fluopyram standard curve in step (1) to obtain the actual residual fluopyram content in the sample to be tested.

[0037] Among them, the instrument conditions for ultra-high performance liquid chromatography tandem mass spectrometry are the same as those in Example 1.

[0038] Table 7 Recovery rates and precisions of fluopyram

[0039] Detect and analyze the fluopyram residues in 20 randomly selected shiitake mushroom samples according to the above detection steps. The residue amounts are all < 0.002 mg / kg.

[0040] Example 8 1. Main instrument and equipment (same as in Example 1) 2. Determination method (1) Drawing of the standard curve (same as in Example 1) (2) Sample extraction Weigh 2.0 g of crushed green tea samples, add 10 mL of water and 20 mL of acetonitrile, vortex for 3 min, centrifuge for 3 min, and freeze at -20 °C for 30 min to separate the acetonitrile phase and the water phase; (3). Purification Absorb 5 mL of the acetonitrile solution to be purified and directly pass it through a polymethylene diphenyl diisocyanate - polypropylene glycol solid phase extraction column. Collect the filtrate for future testing; (4). Determination of the recovery rate Weigh 15 portions of 2.0 g of crushed blank green tea samples, add them at three levels of 0.002 mg / kg, 0.01 mg / kg, and 0.1 mg / kg respectively, repeat steps (2) and (3), repeat each addition concentration 5 times, conduct ultra-high performance liquid chromatography tandem mass spectrometry analysis, obtain the determination values of fluopyram, and calculate the recovery rates. The data are shown in Table 8; (5) Determination of the fluopyram content in the sample Compare and calculate the fluopyram content detected in step (3) with the fluopyram standard curve in step (1) to obtain the actual residual fluopyram content in the sample to be tested.

[0041] Among them, the conditions of the ultra-high performance liquid chromatography-tandem mass spectrometry instrument are the same as those in Example 1.

[0042] Table 8 Recovery and Precision of Fluopicolide

[0043] According to the above detection steps, the fluopicolide residue in 20 randomly selected green tea samples was detected and analyzed, and the residue amount was all < 0.002 mg / kg.

[0044] Example 9 1. Main Instrument and Equipment (Same as Example 1) 2. Determination Method (1) Standard Curve Drawing (Same as Example 1) (2) Sample Extraction Weigh 2.0 g of crushed Chinese prickly ash samples, add 10 mL of water and 12 mL of acetonitrile, vortex for 3 min, centrifuge for 3 min, and freeze at -18 °C for 30 min to separate the acetonitrile phase and the water phase. (3). Purification Pipette 4 mL of the acetonitrile solution to be purified directly through a polymethylene diphenyl diisocyanate-poly(tetrahydrofuran) solid-phase extraction column, collect the filtrate for later measurement. (4). Recovery Determination Weigh 15 portions of 2.0 g of blank Chinese prickly ash samples after crushing, add them at three levels of 0.002 mg / kg, 0.01 mg / kg, and 0.1 mg / kg respectively, repeat steps (2) and (3), repeat each addition concentration 5 times, perform ultra-high performance liquid chromatography-tandem mass spectrometry analysis, obtain the measured values of fluopicolide, and calculate the recovery rate. The data are shown in Table 9. (5). Determination of Fluopicolide Content in Samples Compare and calculate the fluopicolide content detected in step (3) with the fluopicolide standard curve in step (1) to obtain the actual residual fluopicolide content in the sample to be measured.

[0045] Among them, the conditions of the ultra-high performance liquid chromatography-tandem mass spectrometry instrument are the same as those in Example 1.

[0046] Table 9 Recovery and Precision of Fluopicolide

[0047] According to the above detection steps, the fluopicolide residue in 20 randomly selected Chinese prickly ash samples was detected and analyzed, and the residue amount was all < 0.002 mg / kg.

[0048] The preferred embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0049] In addition, it should be noted that, in the various specific technical features described in the above specific embodiments, they can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combination methods.

[0050] Furthermore, any combination can be made between various different embodiments of the present invention as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A method for determining the residue amount of picolinafen in phytogenic foods, characterized in that It includes the following specific steps: (1). Standard curve drawing Take 0.5 mL of the 1000 mg / L fluopyram standard solution and place it in a 50 mL volumetric flask. Dilute and make up the volume with methanol to obtain a 10 mg / L fluopyram solution. Gradually dilute the 10 mg / L fluopyram solution with methanol to obtain a 0.002 mg / L - 0.1 mg / L fluopyram standard working solution. Perform ultra-high performance liquid chromatography-tandem mass spectrometry analysis and detection. The linear correlation is good. Take the concentration as the abscissa and the peak area as the ordinate for regression to obtain the fluopyram standard curve; (2). Sample extraction Weigh the pulverized sample to be tested, add acetonitrile and water, vortex for 3 min, then centrifuge at room temperature for 3 min and freeze for 30 min to separate the acetonitrile phase and the water phase; (3). Purification Take the upper layer of the acetonitrile solution to be purified and directly pass it through a solid-phase extraction cartridge, and collect the filtrate for testing; (4). Recovery rate determination Weigh the pulverized blank sample, add the fluopyram standard solution at the addition amounts of 0.002 mg / kg, 0.01 mg / kg, and 0.1 mg / kg respectively. Repeat steps (2) and (3), perform ultra-high performance liquid chromatography-tandem mass spectrometry analysis, compare with the fluopyram standard curve in step (1), calculate to obtain the measured value of fluopyram, and calculate the recovery rate; (5). Determination of the fluopyram content in the sample Compare and calculate the fluopyram content detected in step (3) with the fluopyram standard curve in step (1) to obtain the actual fluopyram content in the sample to be tested; In the said step (3), take 3 - 5 mL of the acetonitrile solution to be purified, and the filler of the solid-phase extraction cartridge used is one of diphenylmethane diisocyanate-polyethylene glycol, diphenylmethane diisocyanate-polypropylene glycol, diphenylmethane diisocyanate-polyoxytetramethylene glycol, tolylene diisocyanate-polyethylene glycol, tolylene diisocyanate-polypropylene glycol, tolylene diisocyanate-polyoxytetramethylene glycol, polymethylene diphenyl diisocyanate-polyethylene glycol, polymethylene diphenyl diisocyanate-polypropylene glycol, polymethylene diphenyl diisocyanate-polyoxytetramethylene glycol; In the steps (1) and (4), the liquid chromatography conditions are as follows: chromatographic column: ZORBAX SB C18 2.1×50 mm×3.5 μm; column temperature 30°C; mobile phase A: 0.1% formic acid in water, mobile phase B: methanol; mobile phase gradient: 10% B from 0 to 1.0 min, 10% B to 95% B from 1.0 to 6.0 min, 95% B from 6.0 to 9.0 min, 10% B at 9.5 min; flow rate 0.4 mL / min; injection volume 1 μL; mass spectrometry conditions: atmospheric pressure chemical ionization positive ion mode; desolvation tube temperature 200°C; heating module temperature 200°C; ion source temperature 350°C; drying gas flow rate 5 L / min, nebulizing gas flow rate 3 L / min, collision gas pressure 230 kPa; scanning mode: multiple reaction monitoring; quantitative ion pair of picolinafen: 377 / 238, qualitative ion pairs: 377 / 266 and 377 / 359.

2. The method for determining the residue amount of picolinafen in phytogenic foods according to claim 1, characterized in that: In the step (1), the specific concentration range with good linear correlation is that picolinafen has good linearity between 0.002 mg / L and 0.1 mg / L.

3. The method for determining the residue amount of picolinafen in phytogenic foods according to claim 1, wherein: In the step (1), the standard curve of picolinafen is: Y = 116209646X - 51267, and the correlation coefficient r = 0.9999.

4. The method for determining the residue amount of picolinafen in phytogenic foods according to claim 1, wherein: In the step (2), the mass of the sample to be measured is weighed as 2.0 - 10.0 g, 5 - 10 mL of water is added, 10 - 20 mL of acetonitrile is added, and the freezing temperature is -10°C to -20°C.

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