CN105717213A - GC-NIC-MS measurement method for penflufen residual amount - Google Patents

Abstract

The invention discloses a GC-NCI-MS measurement method for the penflufen residual amount. The method is mainly used for measuring the content of residual penflufen in grains, animal derived food and other complex substrate food agricultural products. Residual penflufen in a sample is extracted with acetonitrile or an acetonitrile solution with 1% of acetic acid in a homogeneous mode, after purification and condensation are conducted through a C18/PSA solid-phase extraction column, gas chromatography-negative chemical ion-mass spectrum (GC-NCI-MS) detection is conducted, a corrected standard work curve is established through an empty substrate solution containing no to-be-measured pesticide, and external standard method quantitation is conducted. The average recovery rate of the method is 88.9-104.7%, the average relative standard deviation (RSD) is 4.2-7.5%, and the detection limit is lower than 1.09 micrograms per kilogram. The method has the advantages of being easy and convenient to operate, rapid, good in impurity removal effect, high in sensitivity, strong in characteristic feature, good in repeatability and accurate in qualifying and quantifying. The technical requirements of America, European Union, Japan and other countries for safety detection on corresponding products can be met, and powerful technical support is provided for ensuring food safety of people in China and healthy development of export trades.

Description

A kind of GC-NCI-MS assay method of fluxapyroxad residual quantity

Technical field

The present invention relates to the GC-NCI-MS assay method of a kind of fluxapyroxad residual quantity, more specifically use gas phase color Spectrum-Negative chemical ionization-mass spectrum (GC-NCI-MS) qualitative, quantitative measures the animals such as Cereals, Carnis Sus domestica, beef, Carnis caprae seu ovis, Carnis Gallus domesticus In the animals and plants derived food of the complex matrices such as muscle and goods, the method for the fluxapyroxad content of residual, belongs to persticide residue Determination techniques field.

Background technology

Fluxapyroxad (fluxapyroxad) is the succinate dehydrogenase inhibitors series bactericidal agent developed by BASF AG. Chemical name: 3-difluoromethyl-1-methyl-N-(3', 4', 5'-trifluoro-biphenyl-2-base)-1H-pyrazole-4-carboxamide；Molecular formula: C18H12F5N3O；Relative molecular mass: 381.3；Fusing point: 157 DEG C；Relative density: 1.42.Dissolubility in solvent (g/L, 20 DEG C): acetone ＞ 250, acetonitrile 168, ethyl acetate 123, methanol 53.4, toluene 20.0.The chemical constitution of fluxapyroxad Formula is as follows:

Fluxapyroxad has efficiently, wide spectrum, holding effect, excellent Uptake and translocation, have a preventive and therapeutic action etc. simultaneously Advantage.It can suppress the elongation of spore-germination, spore pipe, mycelial growth and Sporulation, can effectively prevent and treat corn, Semen sojae atricolor, The Major Diseases of Semen Maydis, Brassica campestris L and special crop etc..This product prevents and treats a series of fungal disease by blade face and seed treatment, As on corn, Semen sojae atricolor, fruit tree and vegetable by Septoria musiva (Septoria), the pathogen of Botrytis cinerea (Botrytis), powdery mildew (Erysiphe), Tail spore bacterium (Cercospora), handle rest fungus (Puccinia), rhizoctonia (Rhizoctonia), nuclear cavity bacteria (Pyrenophora spp.) etc. The disease caused.It is particularly well-suited to bean, the gray mold that preventing and treating is caused by alternaric bacteria (Alternaria spp.) (Botrytis cinerea), rust, powdery mildew and the microbial disease of septoria musiva, soybean rust (Phakopsora), on Cotton Gossypii by By the microbial disease of rod method on disease that Rhizoctonia solani Kuhn (Rhizoctonia solani) causes and Helianthi and oilseeds dish Deng.Under all test doses, the safest to all crops.Fluxapyroxad suitability is strong, can with pyraclostrobin, three Azoles fungicide and the compounding use of other products of BASF.Research shows, fluxapyroxad has than commercially available acid amide fungicides Preferably activity, no matter this product is active, multi-functional, or is all modern at aspects such as interior absorption and rain wash resistance Antibacterial establishes new mark post.BASF intends to introduce fluxapyroxad more than 50 country in the world, makees for planting 100 more On thing.2011, fluxapyroxad was first in Britain's registration and listing, and the country of existing registration and listing includes Australia, U.S. State, Canada, state of European Union 13, Brazilian and Chinese etc..Company predict, this product year peak value sales volume up to 600,000,000 Euros. This is in all SDHI series bactericidal agents, the product that expected value that development company expresses is the highest.

Along with fluxapyroxad registration, promote and use, as countries such as U.S. in China's main exit market, Canada Formulate its maximum allowable residual quantity (MRL) in the food agricultural product such as veterinary antibiotics, Cereals and livestock products, such as the U.S. Regulation fluxapyroxad MRL in fruit and vegerable is 0.5～30mg/kg, MRL in the animal derived food such as livestock products and aquatic products For 0.01mg/kg, in nut and Cereals, MRL is 0.06～15mg/kg；Canada's regulation fluxapyroxad is in fruit and vegerable MRL is 0.02～2mg/kg, and in the animal derived food such as livestock products and aquatic products, MRL is 0.01～0.05mg/kg, at heavily fortified point In fruit and Cereals, MRL is 0.01～3mg/kg；If European Union, Japan and other countries regulation field use pesticide not register in this country, When not formulating corresponding residue limits standard, the food agricultural product being exported to its country include in the animal derived foods such as livestock meat Residue limits all carries out " uniform limit " of 0.01mg/L.

Present stage, the research to fluxapyroxad determination of residual amount method is less, and the detection method of report is mainly vegetable and water Fluxapyroxad method for detecting residue in Guo, these detection methods all use Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) to measure The detection method of fluxapyroxad residual quantity in vegetable and fruit, uses LC-MS/MS to measure food Residual Pesticides in Farm Produce tool There is quick, easy, sensitivity advantages of higher, but due to its price costly, a lot of testing agencies, enterprise or scientific research institutions are not Configure this instrument or configuration number of units is less, when using LC-MS/MS detection due to different compounds, different flowings need to be used Mutually or chromatographic column, such needs are constantly changed chromatographic column, flowing and mutually and are expended the long time and be balanced system, this Determine to constrain in degree the application of LC-MS/MS.The gaschromatographic mass spectrometry (GC-NCI-MS) being equipped with negative chemical ionization source is analyzed Food Residual Pesticides in Farm Produce tool has great advantage, and Negative chemical ionization (NCI source) is referred to as mass spectrum " soft ionization source ", Analyte containing electronegativity group is had high selectivity and high sensitivity, owing to its characteristic is strong, utilizes it to carry out retention analysis Time, matrix interference is little, very accurately object can be carried out qualitative and quantitative analysis.Existing various testing agencies and enterprise all purchase Having put gas chromatograph-mass spectrometer (GC-MS), be also generally all equipped with Negative chemical ionization (NCI), existing a lot of class pesticide are equal -F ,-Cl ,-Br or-COO-etc. are mostly contained containing electronegativity group, organochlorine and pyrethroid pesticide molecule Strong electronegative group；Organophosphorus pesticide molecule mostly contains=and S ,-OR ,-P, the electricity such as-O-,-Cl or-P=O be negative Property group；And the novel agrochemical developed in recent years contains-F group mostly, therefore, use GC-NCI-MS conveniently to realize The multi-residue analysis of Multiple Pesticides, compared with GC-EI-MS, can obtain more preferable capacity of resisting disturbance, lower sensitivity and more preferably Selectivity, but have no the report of the GC-NCI-MS detection method of fluxapyroxad residual quantity in food agricultural product up to now, Fluxapyroxad belongs to electronegativity compound, owing to the food agricultural product substrate such as Cereals, animal derived food is more complicated, must set up Sample-pretreating method that clean-up effect is good and instrumental conditions could meet testing requirement, therefore, set up gas chromatogram- Fluxapyroxad residual quantity in Negative chemical ionization-mass spectrum (GC-NCI-MS) qualitative and quantitative analysis Cereals and animal derived food Detection method significant.

Summary of the invention

It is an object of the invention to provide the GC-NCI-MS assay method of a kind of fluxapyroxad residual quantity, be mainly used in measuring grain Fluxapyroxad residual quantity in the complex matrices food agricultural product such as paddy, animal derived food.

For realizing object above, the technical solution adopted in the present invention is: the GC-NCI-MS of a kind of fluxapyroxad residual quantity Assay method, comprises the steps:

(1) extract

Weigh mixing sample in tool plug centrifuge tube, after adding suitable quantity of water recovery, be quantitatively adding acetonitrile or equal containing the acetonitrile solution of 1% acetic acid Matter or oscillating ultrasonic extract, and are subsequently adding the one in sodium chloride or sodium acetate and anhydrous magnesium sulfate, centrifugal after violent vortex 1min.

(2) purify

Pipette certain volume sample extracting solution, be concentrated into about 1mL, through C₁₈/ PSA Solid-Phase Extraction column purification, acetonitrile eluting, collection is washed De-liquid, after being concentrated to dryness, dissolves constant volume with the acetone that volume ratio is 1/1/normal hexane mixed solvent, after crossing film, treat gas chromatogram- Negative chemical ionization-mass spectrum (GC-NCI-MS) detects.

(3) preparation of standard working solution

When the same kind matrix blank sample of not Fluxapyroxad-containsterilization is processed by above-mentioned steps (1), (2), obtain sample extraction and purify Residue, adds appropriate solvent and standard solution, and vortex mixes, and is configured to the fluxapyroxad series standard work of at least 3 concentration Liquid.

(4) Gas Chromatography-Negative chemical ionization source-mass spectrography (GC-NCI-MS) measures

The standard working solution of each Concentraton gradient in step (3) is carried out GC-NCI-MS mensuration, with the chromatographic peak face of standard working solution Amass and its respective concentration is carried out regression analysis, obtain standard working curve；Sample after purifying in step (2) under the same conditions Product liquid injects GC-NCI-MS and is measured, and records the chromatographic peak area of fluxapyroxad in sample liquid, substitutes into standard working curve, Obtain fluxapyroxad content in sample liquid, then obtain fluorine azoles bacterium acyl in sample according to the Mass Calculation of sample representated by sample liquid Amine residual quantity.If fluxapyroxad residual quantity exceedes the range of linearity upper limit in upper machine solution, need to be with constant volume solvent by dense for upper machine solution Within degree is diluted to the range of linearity.

Step (1) if in the sample of the moisture content less such as sample Cereals and animal livers, suitable quantity of water must be added before extraction abundant Infiltration.

Add sodium chloride when step (1) uses acetonitrile extraction to saltout, use the acetonitrile solution containing 1% acetic acid to add when extracting Sodium acetate is saltoutd.

Step carries out C in (2)₁₈/ PSA Solid phase extraction, during acetonitrile eluting, elution volume is 6～8mL.

In step (4), GC conditions is: chromatographic column: HP-5MS capillary chromatographic column, column length 30m, internal diameter 0.25 Mm, thickness 0.25 μm；Injector temperature 250 DEG C；Carrier gas: He, not shunt mode sample introduction, sample size: 1 μ L；Constant current mould Formula, flow velocity 1.0mL/min；Heating schedule: initial temperature 60 DEG C keeps 2min, rises to 200 DEG C with the speed of 20 DEG C per minute, so After rise to 220 DEG C with the speed of 2 DEG C per minute, then rise to 280 DEG C with the speed of 20 DEG C per minute, keep 10min；Transmission line temperature Degree: 280 DEG C.

In step (4), Mass Spectrometry Conditions is: ion source temperature 150 DEG C；Quadrupole rod temperature 150 DEG C；Ionization pattern: negative chemistry Ionization, i.e. NCI pattern, energy 70eV；Scan mode: Salbutamol Selected Ion Monitoring (SIM) pattern, the ion of monitoring is: 361.1, 362.1、362.9。

When step (4) measures sample liquid and extraction standard working solution, if sample liquid Pesticides chromatographic peak retention time and standard In solution, corresponding pesticide retention time is consistent, and in the sample mass spectrum after background correction, selected ion all occurs, And abundance of ions is more consistent than the abundance of ions ratio with standard solution, then can determine whether sample liquid exists this pesticide；If above-mentioned two Individual condition can not meet simultaneously, then judge without this kind of pesticide.

The beneficial effects of the present invention is:

The present invention utilizes dispersive solid-phase extraction technology, establishes simplicity, quickly and can be prevented effectively from the sample of sample mesostroma interference Product pre-treating method, this pre-treating method combines GC-NCI-MS, and to be applied in Cereals, animal derived food fluxapyroxad fixed Property confirmation and detection by quantitative, average recovery rate is 88.9%～104.7%, and average relative standard's deviation (RSD) is 4.2%～7.5%, Detection limit is less than 1.09 μ g/kg, has easy and simple to handle, quick, accurate, highly sensitive and reproducible advantage.U.S. can be met State, European Union, the Japan and other countries technology requirement to corresponding product safety detection, for ensureing our people's food safety and to going out Mouth trade sound development provides strong technical support.

Accompanying drawing explanation

Fig. 1 is that the GC-NCI-MS being added on the fluxapyroxad in blank Carnis Sus domestica substrate selects chromatography of ions figure.

Fig. 2 is that the GC-NCI-MS of the Carnis Sus domestica blank sample of not Fluxapyroxad-containsterilization selects chromatography of ions figure.

Fig. 3 is the fluxapyroxad standard working curve with the Carnis Sus domestica blank sample of not Fluxapyroxad-containsterilization as substrate preparation.

Detailed description of the invention

Now with following embodiment, the present invention is described, but is not to limit the scope of the present invention.

The instrument used in embodiment and reagent

T18 Basic homogenizer (IKA, Germany)；CR21G III centrifuge (Hitachi, Japan)；MS3 basic model is revolved Whirlpool blender (IKA, Germany)；TurboVap LV pattern product automatic concentration instrument (Caliper, USA)；7890N gas phase color Spectrum-5977C mass spectrograph (Agilent, USA)；C₁₈/ PSA solid-phase extraction column (6mL, 500mg/500mg) is purchased from Tianjin and wins Na Aijieer Science and Technology Ltd..

Reagent

Acetonitrile, acetone, normal hexane (HPLC level, Merke, Germany)；Acetic acid (HPLC level, CNW, Germany)； Anhydrous magnesium sulfate, sodium chloride and sodium acetate are analytical pure, are purchased from Chemical Reagent Co., Ltd., Sinopharm Group.

Standard substance: purity 99.5%, purchased from Dr.Ehrenstorfer company of Germany.

Embodiment 1: the detection of fluxapyroxad residual quantity in Semen Tritici aestivi

(1) sample pre-treatments

Extract

Weigh through the abundant 5g wheat samples (grinding to form flour) mixed in 50mL centrifuge tube, after adding 20mL water recovery 30min, Accurately add the 20mL acetonitrile solution containing 1% acetic acid, mechanical shaking extraction 20min, supersound extraction 5min, add 3g anhydrous magnesium sulfate With 2g sodium acetate, after vortex 1min, 7000r/min is centrifuged 5min.After Li Xin, take 8mL acetonitrile extraction liquid in 40 DEG C rotation steam or Nitrogen is blown near dry, after adding 1mL acetonitrile vortex, to be clean.

Purify

With 5mL acetonitrile prewashing C₁₈/ PSA solid-phase extraction column, when liquid level arrives the top of adsorbent, proceeds to post by said extracted solution In, wash test tube with 2mL acetonitrile, and cleaning mixture is moved in SPE post, when solution reaches adsorbent top, add 4mL Acetonitrile carries out eluting to pillar, and eluent all receives in quantitative test tube, nitrogen dry up after with the acetone that volume ratio is 1/1/ Normal hexane mixed solvent is settled to 1mL, after crossing 0.22 μm filter membrane, treats that GC-NCI-MS measures.

(2) preparation of standard working solution

Accurately weighing 25 ± 0.1mg standard substance in 25mL volumetric flask, dissolve with methanol, constant volume obtains 1000.0 μ g/mL standard reserving solutions； Pipette 1.0mL standard reserving solution to be placed in 100mL volumetric flask, obtain with the acetone that volume ratio is 1/1/normal hexane mixed solvent constant volume To 10.0 μ g/mL standard intermediate liquids；10 μ g/mL standard solution dilutions are made into 5,2,1,0.5,0.2,0.1 μ g/mL mark Quasi-solution.The Semen Tritici aestivi blank sample of not Fluxapyroxad-containsterilization is processed by above-mentioned pre-treatment step, obtains sample extraction and purify residue, Adding acetone/normal hexane mixed solvent and the 100 above-mentioned standard solution of μ L that 900 μ L volume ratios are 1/1 in this residue, vortex mixes Even, it is made into 10,20,50,100,200,500 μ g/L extraction standard working solutions.

(3) Gas Chromatography-Negative chemical ionization source-mass spectrography (GC-NCI-MS) measures

The standard working solution of variable concentrations gradient is injected separately into GC-NCI-MS, carries out quantitatively dividing of fluxapyroxad content with external standard method Analysis, i.e. carries out regression analysis with the chromatographic peak area of standard working solution to its respective concentration, obtains standard working curve；Identical Under the conditions of sample extracting solution injected GC-NCI-MS be measured, record the chromatographic peak area of fluxapyroxad, generation in sample liquid Enter standard working curve, obtain fluxapyroxad content in sample liquid, then obtain according to the Mass Calculation of sample representated by sample liquid Fluxapyroxad residual quantity in sample.

Wherein chromatographic condition is:

Chromatographic column: HP-5MS capillary chromatographic column, column length 30m, internal diameter 0.25mm, thickness 0.25 μm.

Injector temperature: 250.0 DEG C, sample introduction pattern: Splitless injecting samples, sample size: 1 μ L.

Carrier gas: He, constant current mode, flow velocity 1.0mL/min.

Furnace box heating schedule: initial temperature 60 DEG C keeps 2min, rises to 200 DEG C with the speed of 20 DEG C per minute, then with per minute The speed of 2 DEG C rises to 220 DEG C, then rises to 280 DEG C with the speed of 20 DEG C per minute, keeps 10min.

Transmission line temperature: 280 DEG C.

Wherein, mass spectrometry parameters is:

Ionization pattern: negative chemical ionization, i.e. NCI pattern, energy 70eV.

Ion source temperature: 150 DEG C；Quadrupole rod temperature 150 DEG C.

Scan mode: Salbutamol Selected Ion Monitoring (SIM) pattern；The ion of SIM monitoring is: 361.1,362.1,362.9, Quota ion is 361.1.

Qualitative Identification: at identical conditions, if sample liquid Pesticides chromatographic peak retention time pesticide corresponding to standard solution Retention time is consistent, and in the sample mass spectrum after background correction, selected ion all occurs, and abundance of ions Ratio is consistent with the abundance of ions ratio of standard solution, then can determine whether to exist in sample liquid this pesticide；If above-mentioned two condition can not be same Time meet, then judge without this kind of pesticide.

With the chromatographic peak area of standard working solution, its respective concentration is carried out regression analysis, obtain standard working curve such as table 1.

The standard working curve of fluxapyroxad in table 1 Semen Tritici aestivi bare substrate

Title	Retention time (min)	Regression equation	Correlation coefficient
				Fluxapyroxad	23.36	Y=238.11X-1610	0.9991

Recovery of standard addition and repeatability:

The fluxapyroxad standard of 10,20 and 200 g/kg3 concentration levels of μ is added in the Semen Tritici aestivi of not Fluxapyroxad-containsterilization Solution, carries out the determination of residual amount by above-mentioned process step after pesticide adds 30min.Mensuration concentration is added dense with pesticide theory Degree compares, and obtains pesticide TIANZHU XINGNAO Capsul, each pitch-based sphere parallel assay 6 times, obtains its relative standard deviation, measures The results are shown in Table 2.As can be seen from Table 2, in 3 mark-on levels, the average recovery rate of fluxapyroxad is 88.9%～104.7%, Average relative standard's deviation (RSD) is 4.2%～5.5%, illustrates that the response rate of the inventive method is higher, reproducible.

The response rate of table 2 fluxapyroxad and repeatability (n=6)

Detection limit:

The fluxapyroxad extraction standard working solution of variable concentrations is injected GC-NCI-MS, molten with least concentration extraction standard 3 times of signal to noise ratios at liquid chromatography peak and the cycles of concentration (cycles of concentration of Semen Tritici aestivi is 2.0 times) of sample handling processes calculate detection limit, The detection of fluxapyroxad is limited to 1.09 μ g/kg.

Embodiment 2: the detection of fluxapyroxad residual quantity in Carnis Sus domestica

(1) sample pre-treatments

Extract

Weigh through the abundant 5g Carnis Sus domestica sample mixed in 50mL centrifuge tube, add the mixing of 5mL water, place 30min, accurately add 20mL acetonitrile, homogenizing extracts 2min, adds 3g anhydrous magnesium sulfate and 2g sodium chloride, and after vortex 1min, 7000r/min is centrifuged 5min.After Li Xin, take 8mL acetonitrile extraction liquid and be blown to about 1mL in 40 DEG C of rotation steamings or nitrogen, to be clean.

Purify

With 5mL acetonitrile prewashing C₁₈/ PSA solid-phase extraction column, when liquid level arrives the top of adsorbent, proceeds to post by said extracted solution In, wash test tube with 2mL acetonitrile, and cleaning mixture is moved in SPE post, when solution reaches adsorbent top, add 4mL Acetonitrile carries out eluting to pillar, and eluent all receives in quantitative test tube, nitrogen dry up after with the acetone that volume ratio is 1/1/ Normal hexane mixed solvent is settled to 1mL, after crossing 0.22 μm filter membrane, treats that GC-NCI-MS measures.

(2) preparation of standard working solution

Acetone/normal hexane mixed solvent that 1000 μ g/mL standard solution volume ratios are 1/1 is diluted to 10 μ g/mL standard intermediate liquids, will 10 μ g/mL standard solution dilutions are made into 5,2,1,0.5,0.2,0.1 μ g/mL standard solution.Pig by not Fluxapyroxad-containsterilization Meat blank sample is processed by above-mentioned pre-treatment step, obtains sample extraction and purifies residue, and adding 900 μ L volume ratios in this residue is The acetone of 1/1/normal hexane mixed solvent and the 100 above-mentioned standard solution of μ L, vortex mixes, be made into 10,20,50,100,200, 500 μ g/L extraction standard working solutions.

(3) Gas Chromatography-Negative chemical ionization source-mass spectrography (GC-NCI-MS) measures

Operating procedure, chromatograph are consistent with the mensuration of fluxapyroxad in above-mentioned wheat samples with Mass Spectrometry Conditions.

Qualitative Identification: consistent with the mensuration of fluxapyroxad in above-mentioned wheat samples.

Linear relationship:

With the chromatographic peak area of standard working solution, its respective concentration being carried out regression analysis, obtaining standard working curve is

Y=249.73X-692.44, correlation coefficient is 0.9994.

Recovery of standard addition and repeatability:

The fluxapyroxad standard of 10,20 and 200 3 concentration levels of μ g/kg is added in the Carnis Sus domestica of not Fluxapyroxad-containsterilization Solution, carries out the determination of residual amount by above-mentioned process step after pesticide adds 30min, adds dense by mensuration concentration with pesticide theory Degree compares, and obtains pesticide TIANZHU XINGNAO Capsul, each pitch-based sphere parallel assay 6 times, obtains its relative standard deviation, measures The results are shown in Table 3.As can be seen from Table 3, in 3 mark-on levels, the average recovery rate of fluxapyroxad is 93.6%～95.4%, Average relative standard's deviation (RSD) is 5.0%～7.5%, illustrates that the response rate of the inventive method is high, reproducible.

The response rate of table 3 fluxapyroxad and repeatability (n=6)

Detection limit:

The fluxapyroxad extraction standard working solution of variable concentrations is injected GC-NCI-MS, molten with least concentration extraction standard 3 times of signal to noise ratios at liquid chromatography peak and the cycles of concentration (cycles of concentration of Carnis Sus domestica is 2.0 times) of sample handling processes calculate detection limit, The detection of fluxapyroxad is limited to 0.97 μ g/kg.

Above embodiment is only to be described the preferred embodiment of the present invention, not limits the scope of the present invention Fixed, on the premise of designing spirit without departing from the present invention, it is each that technical scheme is made by this area ordinary skill technology Plant modification and improvement, all should fall in the protection domain that claims of the present invention determines.

Claims (5)

1. the GC-NCI-MS assay method of a fluxapyroxad residual quantity, it is characterised in that said method comprising the steps of:

(1) extract

Weigh mixing sample in tool plug centrifuge tube, after adding suitable quantity of water, after adding acetonitrile or extracting containing the acetonitrile solution homogenizing of 1% acetic acid or oscillating ultrasonic, add the one in sodium chloride or sodium acetate and anhydrous magnesium sulfate, centrifugal after violent vortex 1min；

(2) purify

Pipette certain volume sample extracting solution, be concentrated into about 1mL, through C₁₈/ PSA Solid-Phase Extraction column purification, acetonitrile eluting, collect eluent, after being concentrated to dryness, dissolve constant volume with the acetone that volume ratio is 1/1/normal hexane mixed solvent, after crossing film, treat Gas Chromatography-Negative chemical ionization source-mass spectrum (GC-NCI-MS) detection；

(3) preparation of standard working solution

The same kind matrix blank sample of not Fluxapyroxad-containsterilization is processed by above-mentioned steps (1), (2), obtain sample extraction and purify residue, adding appropriate solvent and standard solution, vortex mixes, and is configured to the fluxapyroxad series standard working solution of at least 3 concentration；

(4) measure and result calculates

The standard working solution of each Concentraton gradient in step (3) is carried out GC-NCI-MS mensuration, with the chromatographic peak area of standard working solution, its respective concentration is carried out regression analysis, obtain extraction standard working curve；Sample liquid after purifying in step (2) under the same conditions is injected GC-NCI-MS and is measured, record the chromatographic peak area of fluxapyroxad in sample liquid, substitute into extraction standard working curve, obtain fluxapyroxad content in sample liquid, then obtain fluxapyroxad residual quantity in sample according to the Mass Calculation of sample representated by sample liquid；If fluxapyroxad residual quantity exceedes the range of linearity upper limit in upper machine solution, within upper machine solution concentration need to being diluted to the range of linearity with constant volume solvent.

The GC-NCI-MS assay method of a kind of fluxapyroxad residual quantity the most according to claim 1, it is characterised in that step (1) if in the sample of sample moisture content less, suitable quantity of water must be added before extraction and fully infiltrate.

The GC-NCI-MS assay method of a kind of fluxapyroxad residual quantity the most according to claim 1, it is characterized in that, sodium chloride need to be added when step (1) uses acetonitrile extraction to saltout, use the acetonitrile solution containing 1% acetic acid need to add sodium acetate when extracting and saltout.

The GC-NCI-MS assay method of a kind of fluxapyroxad residual quantity the most according to claim 1, it is characterised in that step carries out C in (2)₁₈/ PSA Solid phase extraction, during acetonitrile eluting, elution volume is 6～8mL.

The GC-NCI-MS assay method of a kind of fluxapyroxad residual quantity the most according to claim 1, it is characterized in that, in step (4), GC-NCI-MS analysis condition is: chromatographic column: HP-5MS capillary chromatographic column, column length 30m, internal diameter 0.25mm, thickness 0.25 μm；Injector temperature 250.0 DEG C；Carrier gas: He, not shunt mode sample introduction, sample size: 1 μ L；Constant current mode, flow velocity 1.0mL/min；Heating schedule: initial temperature 60 DEG C keeps 2min, rises to 200 DEG C with the speed of 20 DEG C per minute, then rises to 220 DEG C with the speed of 2 DEG C per minute, then rises to 280 DEG C with the speed of 20 DEG C per minute, keeps 10min；Transmission line temperature: 280 DEG C；Ionization pattern: negative chemical ionization, i.e. NCI pattern, energy 70eV；Ion source temperature 150 DEG C；Scan mode: Salbutamol Selected Ion Monitoring (SIM) pattern, the ion of monitoring is: the ion of monitoring is: 361.1,362.1,362.9.