JP2016180710A - Method of preparing samples for analyzing residual pesticides - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of easily, quickly, and accurately analyzing residual pesticides in food.SOLUTION: Residual pesticides are extracted from food using a water soluble first solvent to prepare a mix solution by mixing the obtained extract with water. The mix solution is injected into a second unit 200 of a centrifuge tube 10 having a first unit 100 and the second unit 200 mounted therein, the first unit having an absorption layer 103 made of a pesticide absorbent and the second unit having a separation membrane 203 that can act as a nanofiltration membrane, ultrafiltration membrane, or microfiltration membrane. Centrifugal force is applied to the centrifuge tube 10 to force the mix solution to pass through the separation membrane 203 and the absorption layer 103 in the described order. After pulling out the first unit 100 and the second unit 200 and washing the centrifuge tube 10, the first unit 100 is reinserted into the centrifuge tube and an extraction solvent is injected thereto, and then centrifugal force is applied to the centrifuge tube 10 to force the extraction solvent to pass through the absorption layer 103. The extraction solvent accumulated at the bottom of the centrifuge tube 10 is used as a sample for simultaneous analysis of residual pesticides.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for preparing a sample for analysis of residual agricultural chemicals, and more particularly to a method for preparing a sample used for analyzing residual agricultural chemicals in food.

  The positive list system, which in principle prohibits the sale of foods with residual agricultural chemicals exceeding the specified amount, was enforced in Japan in 2006, and it is clear that there is no risk of harming human health among many agricultural chemicals Residual standard values have been set for all of the approximately 800 types of pesticides except for pesticides. Therefore, it is necessary to analyze about 800 kinds of agricultural chemicals at the same time for the food to be sold, and the Ministry of Health, Labor and Welfare has notified the analysis method for that purpose (Non-patent Document 1).

  The simultaneous analysis method notified by the Ministry of Health, Labor and Welfare (hereinafter referred to as the “notification method”) is basically a sample preparation process for homogenizing by crushing food samples, and extracting residual pesticides from the prepared samples An extraction step, a purification step for removing contaminants from the extract obtained in the extraction step, and a measurement / analysis step for analyzing the test solution obtained by the purification step. In the extraction step, a solvent (acetonitrile) is added to the sample homogenized in the sample preparation step and homogenized, followed by suction filtration. And after salting out this filtrate, the residue obtained by removing a solvent is melt | dissolved in a mixed solvent (mixed solvent of acetonitrile and toluene), and an extract is prepared. In the purification step, the extract obtained in the extraction step and the mixed solvent of acetonitrile and toluene are injected in this order into the graphite carbon / aminopropylsilylated silica gel laminated minicolumn to obtain an eluate from the minicolumn. Then, a predetermined amount of the test solution is prepared by dissolving the residue obtained by removing the solvent from the eluate in a predetermined solvent. In the measurement / analysis step, the prepared test solution is analyzed by GC / MS, GC / MS / MS, LC / MS, or LC / MS / MS, thereby simultaneously evaluating agricultural chemicals contained in the food sample.

  However, the notification method requires a large amount of organic solvent due to the use of a mini-column, and the operation process is complicated and requires several steps to remove the solvent. It takes a long time to prepare a possible test solution.

  Thus, a QuEChERS method (Catchers method) has been proposed in which a sample for analysis can be obtained in a short time by a simple operation (Non-Patent Document 2). The QuEChERS method is also adopted in EU standards, and is being adopted by food business operators and the like in Japan as a simultaneous analysis method for residual agricultural chemicals replacing the notification method.

  The QuEChERS method analyzes an extraction process for extracting residual agricultural chemicals from food samples, a salting-out process of the extract obtained in the extraction process, a purification process of the extract that has undergone the salting-out process, and an extract that has undergone the purification process. Measurement and analysis process. In the extraction process, acetonitrile is added to the food sample and the residual pesticide is extracted by shaking. In the salting out process, salt is added to the extract obtained in the extraction process and shaken to separate water and acetonitrile. The residual pesticides contained in the extract are transferred to the acetonitrile layer, and are highly polar. The contaminated substances are transferred to the water layer. In the purification process, a powdered or granular solid phase such as ethylenediamine-N-propylsilylated silica gel or graphite carbon capable of adsorbing contaminants contained in the extract subjected to the salting-out process is added to and dispersed in the extract. After centrifugation, centrifuge. In the measurement / analysis process, the supernatant solution obtained by centrifugation in the purification process is analyzed by GC / MS, LC / MS, or LC / MS / MS to simultaneously evaluate pesticides contained in food samples. .

  The QuEChERS method removes contaminants contained in the extract by adding a solid phase to the extract and is therefore easier to operate than the notification method using a mini-column. Sample (test solution) can be prepared, but because the purification process is dispersed solid-phase extraction, contaminants such as food matrix are likely to remain in the test solution, which may affect the analysis results. There is. Further, the obtained test solution may significantly contaminate an analytical instrument such as GC / MS and its column due to contaminants.

Ministry of Health, Labor and Welfare, “Testing methods for substances remaining in foodstuffs such as agricultural chemicals, feed additives or veterinary drugs”, [March 9, 2015 search], Internet (URL: http: //www.mhlw. go.jp/stf/seisakunitsuite/bunya/kenkou_iryou/shokuhin/zanryu/zanryu3/siken.html)

Food Analysis and Development Center SUNATEC, “QuEChERS Law”, [March 9, 2015 search], Internet (URL: http://www.mac.or.jp/mail/140401/03.shtml)

  The present invention is intended to enable analysis of residual agricultural chemicals in foods easily, in a short time, and with high accuracy.

  The present invention relates to a method for preparing a sample used for analyzing residual agricultural chemicals in food. In this preparation method, a pesticide residue is extracted from food using a water-soluble first solvent, and the resulting extract is mixed with water to prepare a mixed solution, a nanofiltration membrane, and an ultrafiltration membrane. Alternatively, using a separation membrane that can be used as a microfiltration membrane, Step 2 for obtaining a filtrate by filtering the mixed solution, Step 3 for passing the filtrate through an adsorbent capable of adsorbing residual agricultural chemicals in the filtrate, and Step 3 Then, the process 4 which makes the adsorbent pass the 2nd solvent which can extract a residual agrochemical is included.

  When the mixed solution prepared in step 1 is filtered in step 2, a mixed solution from which solids contained in the extract are separated is obtained as a filtrate. Since a predetermined separation membrane is used in step 2, the residual agricultural chemical contained in the mixed solution passes through the separation membrane and remains in the filtrate. When this filtrate is passed through the adsorbent in step 3, residual agricultural chemicals contained in the filtrate are adsorbed by the adsorbent, and contaminants contained in the filtrate pass through the adsorbent together with the filtrate. Then, when the second solvent is passed through the adsorbent in step 4, the residual agricultural chemical adsorbed on the adsorbent is extracted by the second solvent. Therefore, the second solvent that has passed through the adsorbent can be used as a sample for analyzing residual agricultural chemicals in food.

  In the preparation method of the present invention, for example, Step 2, Step 3, and Step 4 can be performed by applying centrifugal force to the mixed solution, the filtrate, and the second solvent, respectively.

  In this case, Step 2, Step 3 and Step 4 can be executed efficiently, and the target analytical sample can be prepared more easily and quickly.

  The separation membrane used in step 2 is, for example, polysulfone resin, polyether sulfone resin, polyvinylidene fluoride resin, aromatic polyamide resin, cellulose acetate resin, polytetrafluoroethylene resin, polyamide resin, polyacrylonitrile resin, polyvinyl chloride. -An organic film or an alumina film made of a resin material selected from the group consisting of a polyacrylonitrile copolymer resin and a polycarbonate resin.

  The organic membrane used as the separation membrane is preferably subjected to plasma treatment or ozone treatment. The organic film that has been subjected to plasma treatment or ozone treatment has increased hydrophilicity, so that residual agricultural chemicals are less likely to adhere to it, and the residual agricultural chemicals contained in the mixed solution can pass smoothly.

  The adsorbent used in step 3 is, for example, at least one selected from the group consisting of styrene / divinylbenzene copolymer resin, divinylbenzene copolymer resin, cyanopropylated silica gel, phenylated silica gel, and octadecylated silica gel. is there.

  One form of the preparation method of the present invention further includes a step 5 of allowing the second solvent that has passed through the adsorbent to pass through a purified material that can adsorb the contaminant contained in the second solvent that has passed through the adsorbent. When step 5 is included, since the contaminants remaining in the second solvent that has passed through the adsorbent are captured by the purified material, an analysis sample that is less susceptible to the effects of contaminants can be prepared.

  Step 5 can be performed, for example, by applying a centrifugal force to the second solvent. In this case, step 5 can be performed efficiently, and the target analytical sample can be prepared more easily and quickly.

  The purification material used in step 5 is at least one selected from the group consisting of, for example, ethylenediamine-N-propylsilylated silica gel, aminopropylsilylated silica gel, graphite carbon, octadecylated silica gel, and magnesium silicate.

  In the preparation method of the present invention, for example, acetonitrile or methanol is used as the first solvent, and at least one selected from the group consisting of acetone, toluene, dichloromethane and hexane is used as the second solvent. Also use a low polarity.

  This invention which concerns on another viewpoint is related with the kit for preparing the sample used in order to analyze the residual agricultural chemical of foodstuffs by the preparation method of this invention. This preparation kit adsorbs residual pesticides contained in a mixture of water and a water-soluble solvent that can dissolve residual pesticides that can be inserted into and removed from the centrifuge tube with the bottom closed. A first unit capable of partitioning the inside of a centrifuge tube up and down with an adsorbable layer that is capable of liquid permeability, and a nanofiltration membrane, an ultrafiltration membrane that can be inserted into and removed from the inside of the first unit, or And a second unit capable of partitioning the inside of the centrifuge tube vertically above the adsorption layer of the first unit by a separation membrane that can be used as a microfiltration membrane.

  When the first unit is inserted into the centrifuge tube, the mixed solution containing the residual agricultural chemical is injected into the second unit of the preparation kit in which the second unit is inserted into the first unit, and the centrifuge tube is applied to the centrifuge. The mixed liquid receives centrifugal force and passes through the separation membrane of the second unit and the adsorption layer of the first unit in this order. At this time, the solid content contained in the mixed solution is separated by the separation membrane, and the residual agricultural chemical that has passed through the separation membrane together with the mixed solution is adsorbed by the adsorption layer.

  Next, the first unit is extracted from the centrifuge tube together with the second unit, and the mixed liquid accumulated at the bottom of the centrifuge tube is discarded. After washing the centrifuge tube, only the removed first unit is inserted into the centrifuge tube again, and a residual pesticide extraction solvent is injected into the first unit. When the centrifuge tube is applied to the centrifuge, the extraction solvent receives centrifugal force and passes through the adsorption layer of the first unit. At this time, the residual pesticide adsorbed on the adsorption layer is extracted by an extraction solvent that passes through the adsorption layer. Therefore, the pesticide residual liquid by the extraction solvent accumulates at the bottom of the centrifuge tube. When the first unit is extracted again from the centrifuge tube, the extract stored at the bottom of the centrifuge tube can be extracted, and this extract can be used as a sample for analysis of residual agricultural chemicals.

  One embodiment of the preparation kit according to the present invention is capable of adsorbing contaminants mixed in residual pesticides that can be inserted into and removed from the inside of the centrifuge tube and the first unit can be inserted into and removed from the inside. In addition, a third unit capable of partitioning the inside of the centrifuge tube vertically between the bottom portion and the adsorption layer of the first unit by a purified layer having liquid permeability is further provided.

  The third unit can be inserted into the centrifuge tube after washing, and the first unit can be inserted into the third unit inserted into the centrifuge tube. When the extraction solvent for residual agricultural chemicals is injected into the first unit of the centrifuge tube in which the third unit and the first unit are inserted in this way, and the centrifuge tube is applied to a centrifuge, the extraction solvent receives centrifugal force. It passes through the adsorption layer of the first unit and the purification layer of the third unit in this order. At this time, the residual pesticide adsorbed on the adsorption layer is extracted by the extraction solvent that passes through the adsorption layer, and the contaminant contained in the extraction solvent from which the residual pesticide is extracted passes through the purification layer. When adsorbed on the purification layer. Therefore, the pesticide residual liquid by the extraction solvent accumulates at the bottom of the centrifuge tube. When the third unit and the first unit are extracted from the centrifuge tube, the extract stored at the bottom of the centrifuge tube can be extracted, and this extract can be used as a sample for analysis of residual agricultural chemicals. Since this sample for analysis is one in which impurities are removed by the purification layer, the analysis accuracy of residual agricultural chemicals can be improved.

  The preparation kit according to the present invention may include two same centrifuge tubes. In this case, the first unit can be removed together with the second unit from the centrifuge tube in which the mixed liquid has accumulated at the bottom, and the removed second unit can be inserted into another centrifuge tube to execute the next step. It is not necessary to clean the centrifuge tube during the preparation of the pesticide analysis sample.

  Since the method for preparing an analytical sample for residual agricultural chemical according to the present invention includes the above-described steps, an analytical sample capable of analyzing the residual agricultural chemical in food with high accuracy can be prepared easily and in a short time. .

  Since the kit for preparing a pesticide residue analysis sample according to the present invention is a combination of a first unit having an adsorption layer and a second unit having a separation membrane for a centrifuge tube, the pesticide residue in food is highly accurate. It is possible to easily prepare an analytical sample that can be analyzed easily and quickly.

The longitudinal cross-sectional view of one form of the preparation sample preparation kit for analysis based on this invention. The longitudinal cross-sectional view of the state which isolate | separated the said preparation kit for every element. The figure which shows 1 process of the preparation method of the sample for analysis using the said preparation kit. The figure which shows the other process of the preparation method of the sample for analysis using the said preparation kit. The figure which shows the other process of the preparation method of the sample for analysis using the said preparation kit. The figure which shows the other process of the preparation method of the sample for analysis using the said preparation kit. Sectional drawing of the plasma processing apparatus used in the Example. The GC / MS SCAN chromatogram of the analytical sample obtained in Example 1 and Comparative Example 1. The GC / MS SCAN chromatogram of the analytical trial material obtained in Example 2 and Comparative Example 2. The GC / MS SCAN chromatogram of the analytical sample obtained in Example 2 and Comparative Example 3.

  With reference to FIG. 1 and FIG. 2, one form of the sample preparation kit for analysis which concerns on this invention is demonstrated. This analytical sample preparation kit 1 uses an analytical instrument such as a gas chromatograph mass spectrometer (GC / MS) or a liquid chromatograph mass spectrometer (LC / MS) that can simultaneously analyze a multi-component-containing sample, so that it remains from the food. Prepare an analytical sample suitable for analyzing residual agricultural chemicals in foods, especially an analytical sample suitable for simultaneous analysis, prepared from the extract obtained by extracting agricultural chemicals from the mixture described below The centrifuge tube 10, the first unit 100, the second unit 200, and the third unit 300 are mainly provided.

  The centrifuge tube 10 and each unit 100, 200, 300 are formed using a solvent-resistant resin such as polypropylene resin, polyethylene resin, polytetrafluoroethylene resin, perfluoroalkoxyalkane resin, or polyamide resin. is there. The centrifuge tube 10 may be made of glass.

  The centrifuge tube 10 is a cylindrical container applicable to a centrifuge that can be used in a laboratory. The centrifuge tube 10 is closed by opening the entire upper end and forming a conical bottom.

  The first unit 100 is a cylindrical container that can be inserted into and removed from the inside of the centrifuge tube 10. The first unit 100 is open at the top and has a first liquid passage hole 101 at the center of the bottom. The upper part of the first unit 100 has a first flange portion 102 protruding in the horizontal direction. Further, the adsorption layer 103 is disposed on the entire bottom of the first unit 100.

  The adsorption layer 103 is formed at the bottom of the first unit 100 by filling a powder, particulate, or granular adsorbent that can adsorb residual agricultural chemicals contained in the mixed solution to a certain thickness. Yes, it has liquid permeability that allows the liquid mixture to pass through.

  The adsorbent used in the adsorption layer 103 is capable of adsorbing residual agricultural chemicals contained in the mixed solution, while being capable of desorbing the agricultural chemicals adsorbed when it comes into contact with a low polarity solvent. Examples of the adsorbent having such a function include various carbon-based materials such as basic, neutral or acidic alumina, silica, activated carbon, graphite carbon, mesoporous carbon or activated carbon fiber, or styrene / divinylbenzene. A resin porous body formed using a resin material such as a polymer resin or a divinylbenzene copolymer resin can be used. As the styrene / divinylbenzene copolymer resin, various resins can be used as long as they contain styrene and divinylbenzene as structural units. For example, styrene / divinylbenzene copolymer resin and styrene / divinylbenzene / methacrylate. A copolymer resin can be used. As the divinylbenzene copolymer-based resin, various resins can be used as long as they contain divinylbenzene as a structural unit. For example, divinylbenzene / methacrylate copolymer resins and divinylbenzene / vinylpyrrolidone copolymers can be used. Resin can be used.

  As the adsorbent, a material into which a functional group is introduced by chemical modification may be used in order to enhance the adsorptivity of the agricultural chemical contained in the mixed solution. For example, various aluminas and silicas used as adsorbents may have an aromatic ring such as a cyanopropyl group, a phenyl group, or an octadecyl group, or an alkyl chain introduced therein. In addition, the resin material may be a resin material into which a carboxy group or a piperazine group is introduced, such as a carboxydivinylbenzenevinylpyrrolidone copolymer resin or a piperazine divinylbenzenevinylpyrrolidone copolymer resin.

  Particularly preferred adsorbents are styrene / divinylbenzene copolymer resins, divinylbenzene copolymer resins, cyanopropylated silica gel, phenylated silica gel, or octadecylated silica gel.

  The adsorbent can be appropriately selected according to the type of solvent used in the preparation of the target analytical sample. In this case, two or more kinds can be used together by mixing or laminating. Further, the adsorbent may be used by mixing with other materials as long as the adsorbability of the residual agricultural chemical contained in the mixed solution and the desorption of the residual agricultural chemical when touched with a low polarity solvent are not impaired.

  On the bottom surface of the first unit 100, a liquid-permeable net or sheet (not shown) for preventing leakage of the adsorbent from the first liquid passage hole 101 is arranged.

  The second unit 200 is a cylindrical container that can be inserted into and removed from the inside of the centrifuge tube 10. The entire upper part is open and has a first liquid passage hole 201 at the center of the bottom part. The upper part of the second unit 200 has a second flange portion 202 protruding in the horizontal direction. In the second unit 200, the outer diameter of the container portion is set to be substantially the same as the inner diameter of the first unit 100 so that the second unit 200 can be inserted into the first unit 100, and the outer diameter of the second flange portion 202 is the first flange. The setting is the same as that of the unit 102.

  In the second unit 200, the separation membrane 203 is disposed on the entire bottom. The separation membrane 203 has a function as a nanofiltration membrane, an ultrafiltration membrane, or a microfiltration membrane that can separate contaminants other than the residual agricultural chemical and the solvent from the mixed solution. And a material having solvent resistance.

  As such a separation membrane 203, an organic membrane or an inorganic membrane can be used. The organic film is a film formed using an organic material, for example, polysulfone resin, polyether sulfone resin, vinylidene fluoride resin, aromatic polyamide resin, cellulose acetate resin, polytetrafluoroethylene resin, polyamide resin, Examples thereof include those made of a resin material such as a polyacrylonitrile resin, a polyvinyl chloride-polyacrylonitrile copolymer resin, or a polycarbonate resin. Among these, in terms of solvent resistance, polysulfone resin, polyether sulfone resin, vinylidene fluoride resin, aromatic polyamide resin, polytetrafluoroethylene resin or polyamide resin is particularly preferable.

  On the other hand, the inorganic film is a film formed using an inorganic material, and examples thereof include those made of alumina, titanium oxide, zirconia, or the like. Of these, an alumina film is preferable.

  When a nanofiltration membrane or an ultrafiltration membrane is used as the separation membrane 203, it is preferable to use one having a pore size of at least 1,000 molecular weight cut-off (MWCO), in particular, one having a pore size of at least 3,000 MWCO. Nanofiltration membranes and ultrafiltration membranes with a pore size of less than 1,000 MWCO have a high separation effect between residual agricultural chemicals and contaminants, but it is necessary to apply a higher pressure to filter the mixed solution. If mistaken, some solid contaminants may pass through the separation membrane 203 together with residual agricultural chemicals.

  Further, when a microfiltration membrane is used as the separation membrane 203, the pore diameter is preferably 0.1 μm or less. A microfiltration membrane having a pore diameter exceeding 0.1 μm may cause a solid contaminant to pass through together with residual agricultural chemicals.

  When an organic membrane is used as the separation membrane 203, it is preferable that the organic membrane, particularly an organic membrane having a function as a nanofiltration membrane, is subjected to plasma treatment or ozone treatment. The organic film that has been subjected to plasma treatment or ozone treatment has increased hydrophilicity, so that residual agricultural chemicals are less likely to adhere to it, and the residual agricultural chemicals contained in the mixed solution can pass smoothly. In addition, even if the nanofiltration membrane has a pore size of less than 1,000 MWCO, residual pesticides can be passed smoothly through plasma treatment or ozone treatment, so that a high pressure is used to filter the mixture. Even if it does not add, it can isolate | separate a pesticide residue and a contaminant with high precision.

  The third unit 300 is a cylindrical container that can be inserted into and removed from the inside of the centrifuge tube 10. The third unit 300 is open at the top and has a third liquid passage hole 301 at the center of the bottom. The upper part of the third unit 300 has a third flange portion 302 protruding in the horizontal direction. The outer diameter of the container portion of the third unit 300 is set to be substantially the same as the inner diameter of the centrifuge tube 10, and the inner diameter of the container portion of the first unit 100 is such that the first unit 100 can be inserted therein. It is set to be approximately the same as the outer diameter. The outer diameter of the third flange portion 302 is set to be the same as that of the first flange portion 102.

  As for the 3rd unit 300, the refinement | purification layer 303 is arrange | positioned at the whole bottom part. The purification layer 303 has a constant thickness of a powdery, particulate, or granular purification material that can adsorb impurities other than residual agricultural chemicals contained in the low-polarity extraction solvent described below at the bottom of the third unit 300. It is formed by filling in, and has a liquid permeability through which the extraction solvent can pass.

  The purification material used in the purification layer 303 is capable of adsorbing contaminants contained in the extraction solvent, while being difficult to adsorb residual agricultural chemicals contained in the extraction solvent, that is, adsorbing contaminants, It is possible to separate contaminants and residual pesticides. Examples of the purification material having such a function include various carbon-based materials such as basic, neutral or acidic alumina, silica, magnesium silicate, activated carbon, graphite carbon or activated carbon fiber, or styrene / divinylbenzene. A resin porous body formed using a resin material such as a copolymer resin or a divinylbenzene copolymer resin can be used. As the styrene / divinylbenzene copolymer resin and the divinylbenzene copolymer resin, the same resins that can be used as the adsorbent used in the adsorption layer 103 can be used.

  In order to enhance the adsorptivity of the contaminants contained in the extraction solvent, the above-mentioned purified material is chemically modified with ethylenediamine N-propyl group, propylamino group, octadecyl group, octyl group, trimethylaminopropyl group, cyanopropyl group, A functional group such as a phenyl group, a diol group or an amino group may be introduced.

  Particularly preferred as the purification material is ethylenediamine-N-propylsilylated silica gel, aminopropylsilylated silica gel, graphite carbon, octadecylated silica gel or magnesium silicate.

  The purification material can be appropriately selected depending on the type of the extraction solvent used in the preparation of the target analytical sample. In this case, two or more kinds can be used together by mixing or laminating. In addition, the refining material may be used by mixing with other materials as long as it does not impair the separability between contaminants and residual agricultural chemicals.

  On the bottom surface of the third unit 300, a liquid-permeable net or sheet (not shown) for preventing leakage of the purified material from the third liquid passage hole 301 is arranged.

  As shown in FIG. 1, the analysis sample preparation kit 1 is usually integrated by inserting the third unit 300, the first unit 100, and the second unit 200 into the centrifuge tube 10 in this order, and sold in this state. And can be transported. When the units 100, 200, and 300 are integrated into the centrifuge tube 10 by integration, the adsorption layer 103 of the first unit 100 partitions the inside of the centrifuge tube 10 vertically. The separation membrane 203 of the second unit 200 partitions the inside of the centrifuge tube 10 above and below the adsorption layer 103. Further, the purification layer 303 of the third unit 300 divides the inside of the centrifuge tube 10 up and down between its bottom and the adsorption layer 103.

  The integrated sample preparation kit for analysis 1 may be equipped with a lid for closing the opening of the second unit 200 in order to prevent the separation membrane 203 and the like from being contaminated. As this lid, for example, a cover that can be screwed to the outer peripheral surface of the centrifuge tube 10 so as to cover the entire flange portions of the second flange portion 202, the first flange portion 102, and the third flange portion 302, or the entire flange portion is used. The thing which has the softness | flexibility which can be inserted so that it may cover is used.

  When preparing a target analytical sample, the analytical sample preparation kit 1 separates each unit 100, 200, 300 from the centrifuge tube 10 as shown in FIG. In each step of the preparation method, a necessary one of the units 100, 200, 300 is selected and inserted into the centrifuge tube 10.

  Next, a method for preparing an analytical sample used for simultaneous analysis of residual agricultural chemicals in food using the above-described analytical sample preparation kit 1 will be described. The analytical sample preparation method mainly includes the residual agricultural chemical extraction process, the purification process for separating the residual agricultural chemical from the residual agricultural chemical-containing liquid obtained by the extraction process, and the residual agricultural chemical analysis sample separated in the purification process. 3 steps of the preparation process for preparing

(Extraction process)
In this step, the residual agricultural chemical is extracted from the food to be subjected to simultaneous analysis of the residual agricultural chemical, and a predetermined residual agricultural chemical-containing liquid, that is, a mixed solution is prepared (step 1). There are no particular restrictions on the type of food that is used to extract residual agricultural chemicals, such as various agricultural crops, meat, seafood, or processed products thereof. It is made uniform by crushing or chopping.

  Extraction of residual pesticides from food can be carried out according to the method adopted in the notification method or the QuEChERS method. That is, a residual pesticide extraction solvent (first solvent) is added to a homogenized required amount of food sample and homogenized, followed by suction filtration. The solvent for extraction used here is usually a highly polar organic solvent that can dissolve residual agricultural chemicals and is easily soluble in water, such as acetonitrile, methanol, or acetone.

  In general, the filtrate obtained by suction filtration, that is, the residual pesticide extract, is preferably precipitated by adding salt and salting out. The salt used here is sodium chloride, trisodium citrate or its hydrate, disodium hydrogen citrate or its hydrate, anhydrous magnesium sulfate, magnesium sulfate, anhydrous sodium sulfate, sodium sulfate, anhydrous sodium acetate or acetic acid Sodium and the like. These salts may be used in combination as appropriate.

  Next, the extract is centrifuged to separate the solid and the extract. And water is added to an extract and the liquid mixture L of an extract and water is prepared.

(Purification process)
In this step, a filtrate is obtained by filtering the mixed solution L prepared in the extraction step using the separation membrane 203 using the analytical sample preparation kit 1 (step 2), and the filtrate passes through the adsorption layer 103. (Step 3).

  Here, in the sample preparation kit 1 for analysis in which each unit 100, 200, 300 is separated from the centrifuge tube 10, the first unit 100 is inserted into the centrifuge tube 10 as shown in FIG. The second unit 200 is inserted into the 100. And as shown in FIG. 4, the liquid mixture L is inject | poured in the 2nd unit 200, and the centrifuge tube 10 is centrifuged with a centrifuge. By this processing, the mixed liquid L is subjected to centrifugal force and passes through the separation membrane 203 of the second unit 200 as indicated by an arrow in FIG. The filtrate that has passed through the separation membrane 203 scatters into the first unit 100 through the second liquid passage hole 201, passes through the adsorption layer 103 through the application of centrifugal force, and passes through the first liquid passage hole 101 to the centrifuge tube 10. Accumulate at the bottom. At this time, a mainly solid contaminant contained in the mixed solution L is separated from the mixed solution L by the separation membrane 203. In addition, the residual agricultural chemicals contained in the filtrate that has passed through the separation membrane 203 are adsorbed by the adsorbent of the adsorption layer 103, and the contaminants dissolved in the filtrate pass through the adsorption layer 103 together with the filtrate. As a result, the residual agricultural chemical in the mixed solution L is separated from the contaminants, extraction solvent and water contained in the mixed solution L and purified.

  The analytical sample preparation kit 1 after performing the purification step extracts the second unit 200 and the first unit 100 from the centrifuge tube 10 in this order or simultaneously. Then, the liquid mixture L accumulated at the bottom of the second unit 200 and the centrifuge tube 10 is discarded, and the centrifuge tube 10 is washed for the next step.

(Preparation process)
In this step, an extraction solvent (second solvent) capable of extracting residual agricultural chemicals is passed through the adsorption layer 103 (step 4), and the extraction solvent (second solvent) that has passed through the adsorption layer 103 is purified layer 303. (Step 5) to prepare a target analytical sample.

  Here, as shown in FIG. 5, the third unit 300 is inserted into the centrifuge tube 10 washed after the purification step, and the first unit 100 that has undergone the purification step is inserted into the third unit 300. And as shown in FIG. 6, the solvent S for extraction is inject | poured in the 1st unit 100, and the centrifuge tube 10 is centrifuged with a centrifuge. By this treatment, the extraction solvent S passes through the adsorption layer 103 of the first unit 100 as indicated by an arrow in FIG. 6 by applying centrifugal force, and extracts the residual agricultural chemical adsorbed on the adsorbent at that time. In addition, the extraction solvent S that has passed through the adsorption layer 103 scatters into the third unit 300 through the first fluid passage hole 101, and passes through the purification layer 303 through the third fluid passage hole 301 by applying centrifugal force. It collects at the bottom of the centrifuge tube 10. At this time, the contaminants extracted from the adsorption layer 103 together with the residual agricultural chemicals by the extraction solvent S are adsorbed on the purification material and separated from the extraction solvent S.

  The extraction solvent S used in this step is usually an organic solvent having a relatively lower polarity than the extraction solvent (first solvent) used in the extraction step. For example, acetone, toluene, hexane or dichloromethane or these solvents A mixture of those appropriately selected from solvents can be used.

  The extraction solvent S accumulated at the bottom of the centrifuge tube 10 in this step can be collected from the centrifuge tube 10 when the first unit 100 and the third unit 300 are extracted from the centrifuge tube 10 in this order or simultaneously. Since this extraction solvent S is obtained by extracting residual pesticides from the adsorption layer 103, the pesticide residues for simultaneous application to GC / MS, LC / MS, etc. as they are or as necessary are concentrated as needed. It can be used as a sample for analysis.

  The analytical sample preparation kit 1 and the analytical sample preparation method using the analytical sample preparation kit 1 according to the above-described embodiment use the third unit 300 provided with the purification layer 303. Depending on the type and amount, the separation component 203 can sufficiently remove contaminant components, or the contaminant components adsorbed together with the residual agricultural chemicals on the adsorption layer 103 are extracted by the extraction solvent S applied to the adsorption layer 103 in the preparation step. In cases such as when it is difficult, the third unit 300 can be omitted, whereby step 5 can be omitted.

  The sample preparation kit 1 for analysis may have two same centrifuge tubes 10. In this case, there is no need to wash the centrifuge tube 10 when moving from the purification process to the preparation process, and the centrifuge tube 10 used in the purification process and the centrifuge tube 10 used in the preparation process can be used properly.

  In the preparation of the analysis sample, when the water in the mixed solution L is easily adsorbed on the adsorption layer 103 of the first unit 100, the residual pesticide adsorbed on the adsorption layer 103 is extracted with the extraction solvent S. The adsorbed water may be mixed in the extraction solvent S, and as a result, the analysis sample may contain water. In this case, the analytical sample preparation kit 1 is located below the adsorption layer 103 in the centrifuge tube 10 (when the analytical sample preparation kit 1 includes the third unit 300, between the adsorption layer 103 and the purification layer 303). ) A fourth unit capable of disposing a dewatering layer including a dewatering material may be further included as an element. In this case, in the preparation step, a dehydration layer can be disposed below the adsorption layer 103, and the extraction solvent S that has passed through the adsorption layer 103 is removed when passing through the dehydration layer. An analytical sample with less contamination can be prepared.

  As the dehydrating material, various materials such as anhydrous sodium sulfate, anhydrous potassium carbonate, calcium chloride, potassium fluoride, silica gel, molecular sieve or zeolite can be used depending on the type of the extraction solvent S and the like. These dehydrating materials may be used alone or in combination by mixing or laminating two or more kinds. When the analytical sample preparation kit 1 includes the third unit 300, a dehydration layer can be stacked on the purification layer 303 without using the fourth unit.

  In the above-described analytical sample preparation method using the analytical sample preparation kit 1, steps 2, 3, 4 and 5 are executed by centrifuging the centrifuge tube 10 using a centrifuge. The process can also be performed without using a centrifuge. For example, after injecting a liquid mixture, a solvent, or the like into a predetermined unit inserted into the centrifuge tube 10, the internal pressure is increased by airtight introduction of nitrogen gas or air from the opening side of the unit. A solvent or the like can be passed through the separation membrane 203 or the adsorption layer 103.

  When the analytical sample preparation method according to the present invention is carried out using the analytical sample preparation kit 1, a sample for simultaneous analysis of residual agricultural chemicals can be efficiently prepared. It can also be performed by using a general-purpose instrument or device for each process without using it.

  The analytical sample preparation method and preparation kit according to the present invention can also be used to prepare a sample to be used for individually analyzing residual agricultural chemicals in food.

[Plasma treatment of separation membrane]
The separation membrane was subjected to plasma processing using the plasma processing apparatus 400 shown in FIG. The plasma processing apparatus 400 includes a copper rod 410, a first glass tube 420, a second glass tube 430, and a third glass tube 440 that are arranged in order coaxially with the copper rod 410, a first glass tube 420, and a second glass. The first copper plate 421 disposed between the tube 430 and the second copper plate 441 wound around the outer peripheral surface of the third glass tube 440 is provided, and the space between the second glass tube 430 and the third glass tube 440 is provided. When an AC voltage is applied between the copper rod 410 and the second copper sales 441 while flowing argon gas, plasma can be generated between the second glass tube 430 and the third glass tube 440.

  Argon gas containing a small amount of water is passed through the plasma processing apparatus 400 in a state where the separation membrane 500 is wound around the outer peripheral surface of the second glass tube 430, and an AC voltage is applied between the copper rod 410 and the second copper plate 441. did. The surface of the separation membrane 500 was subjected to plasma treatment for 2 minutes by the plasma generated thereby. The flow rate of argon gas was 250 mL / min.

  The separation membrane treated here is a nanofiltration membrane made of polypiperazine amide (trade name “XN45” manufactured by TriSep: molecular weight cut-off (MWCO) 500).

[Preparation of food samples]
Food sample A:
A commercially available cucumber was homogenized by finely chopping, and a food sample A was prepared.
Food sample B:
The food version B was prepared by finely chopping the city version of spinach into fine pieces.

Example 1
10.0 g of food sample A and pesticide standard solution (trade name “Pesticide Standard Mixture 31” from Kanto Chemical Co., Ltd.) were weighed into a 50 mL centrifuge tube and allowed to stand for a while after stirring and mixing. The pesticide standard solution was added so that the concentration in the food sample A was 200 ppb.

  10 mL of acetonitrile was added to a centrifuge tube from which food sample A and the like were weighed and shaken manually for 1 minute. To this was added 1 g of trisodium citrate dihydrate, 0.5 g of disodium hydrogen citrate 1.5 hydrate, 1 g of sodium chloride and 4 g of anhydrous magnesium sulfate, and the mixture was shaken vigorously for another 1 minute. Analyzed. Subsequently, the centrifuge tube was attached to a centrifuge and centrifuged at 3,500 rpm for 10 minutes, and 6.0 mL of water was added to the liquid layer (4.0 mL) in the centrifuge tube to prepare a mixed solution.

  20 mL of a solvent in which acetonitrile and water were mixed at a volume ratio of 2: 3 was passed through the plasma-treated nanofiltration membrane to wash the nanofiltration membrane. And using the filtration cell (trade name "HP4750 Stirred Cell" of STERLITEC) equipped with this nanofiltration membrane, the total amount (10 mL) of the mixed solution is filtered by pressurizing with nitrogen gas, and the first filtrate is filtered. Obtained. Moreover, 5 mL of the solvent which mixed acetonitrile and water by the volume ratio of 2: 3 with the nanofiltration membrane after obtaining the 1st filtrate was filtered in the same way, and the 2nd filtrate was obtained.

  Mixing acetonitrile and water in a volume ratio of 2: 3 in an adsorption column packed with 750 mg of a polymer adsorbent (trade name “InertSep RP-1” of GL Science Co., Ltd .: styrene / divinylbenzene / methacrylate copolymer) 6 mL of the solvent was injected, and air pressure was applied to the adsorption column from the syringe. Thereby, the solvent was passed through the adsorption column, and the eluate was discarded. Next, 5 mL was collected from the mixed filtrate of the first filtrate and the second filtrate, and this mixed filtrate was injected into the adsorption column and passed in the same manner, and the eluate was discarded.

  5 mL of acetone was injected into the adsorption column after passing the mixed filtrate, and this acetone was passed in the same manner to secure an eluate. The eluate was dehydrated with anhydrous sodium sulfate and then concentrated as appropriate to obtain an analytical sample having a sample concentration of 1 g / mL. Here, the sample concentration refers to a concentration representing how much weight 1 mL of the sample for analysis is obtained from the extract of the food sample. For example, when the sample concentration is 1 g / mL, this means that the extract corresponding to 1 g of the food sample is finally concentrated to prepare a 1 mL solution. The sample concentration can be adjusted according to the degree of concentration of the extract.

  The time required for the preparation of the analytical sample was 55 minutes from the start of the operation of adding acetonitrile to the centrifuge tube from which the food sample A and the like were weighed.

Comparative Example 1 (Preparation of analytical sample by QuEChERS method according to European standard EN15662)
10.0 g of food sample A and pesticide standard solution (trade name “Pesticide Standard Mixture 31” from Kanto Chemical Co., Ltd.) were weighed into a first centrifuge tube with a capacity of 50 mL, and allowed to stand for a while after stirring and mixing. The pesticide standard solution was added so that the concentration in the food sample A was 200 ppb.

  10 mL of acetonitrile was added to the first centrifuge tube from which food sample A and the like were weighed and shaken manually for 1 minute. To this was added 1 g of trisodium citrate dihydrate, 0.5 g of disodium hydrogen citrate 1.5 hydrate, 1 g of sodium chloride, and 4 g of anhydrous magnesium sulfate. did. Subsequently, the first centrifuge tube was attached to a centrifuge and centrifuged at 3,500 rpm for 10 minutes.

  To another second centrifuge tube, 150 mg of magnesium sulfate and 25 mg of ethylenediamine-N-propylsilylated silica gel (trade name “InertSep PSA” from GL Sciences Inc.) were added, and 1 mL of the liquid layer separated from the first centrifuge tube was added thereto. The mixture was stirred for 30 seconds with a vortex mixer. Then, the second centrifuge tube was attached to a centrifuge and centrifuged at 13,000 rpm for 2 minutes, and 500 μL of the supernatant in the second centrifuge tube was collected. Three types of phenanthrene d-10, anthracene d-10, and 9-bromoanthracene were added to the supernatant as injection spikes so that the concentration was 100 ppb, respectively, and an analysis sample having a sample concentration of 1 g / mL was prepared. The time required for the preparation of this analytical sample was 30 minutes from the start of the work of adding acetonitrile to the first centrifuge tube in which the food sample A and the like were taken.

Example 2
Conducted except that the plasma-treated nanofiltration membrane was changed to a polytetrafluoroethylene membrane (trade name “Porefluoron membrane” from Poron Industries Co., Ltd .: pore diameter 0.1 μm), which is a microfiltration membrane that has not been plasma-treated. The sample for analysis was prepared from food sample B in the same manner as in Example 1. Further, this analytical sample was further purified.

For the purification of the sample for analysis, a mixture of 30 mg of graphite carbon (trade name “InertSep GC” from GL Sciences Inc.) and 250 mg of aminopropylsilylated silica gel (trade name “InertSep NH ₂ ” from GL Sciences Inc.) is filled. A sample for analysis was injected into the prepared column, and air pressure was applied to the column from a syringe. As a result, the entire amount of the sample for analysis that passed through the column was heated to 40 ° C. and concentrated as appropriate, and then, as an injection spike, three concentrations of phenanthrene d-10, anthracene d-10, and 9-bromoanthracene were each set to a concentration of 100 ppb. It added so that it might become. As a result, two types of analytical samples having a sample concentration of 1 g / mL and 4 g / mL were prepared. The time required for the preparation of the analytical sample and the entire purification process was 70 minutes from the start of the operation of adding acetonitrile to the centrifuge tube from which the food sample B and the like were weighed.

Comparative Example 2 (Preparation of analytical sample by notification method)
20.0 g of food sample B was weighed and added to this with an agrochemical standard solution (trade name “Agricultural Chemical Standard Mixture 31” from Kanto Chemical Co., Inc.) so as to be 50 ppb. 50 mL of acetonitrile was added to this and homogenized, followed by suction filtration to obtain a first filtrate. Moreover, 20 mL of acetonitrile was added to the residue on the filter paper and homogenized, followed by suction filtration to obtain a second filtrate. The 1st filtrate and the 2nd filtrate were match | combined, and acetonitrile was added to this, and the extract was prepared by adjusting to 100 mL correctly.

  To 20 mL of the collected extract, 10 g of sodium chloride and 20 mL of 0.5 mol / L phosphate buffer (pH 7.0) are added, shaken with a shaker and allowed to stand, and the separated aqueous layer is discarded. did. On the other hand, the acetonitrile layer was dehydrated by adding anhydrous sodium sulfate, and after removing anhydrous sodium sulfate by filtration, the solvent was removed at 40 ° C. or lower. To this residue, 2 mL of a solvent prepared by mixing acetonitrile and toluene in a volume ratio of 3: 1 was added to obtain a sample solution.

Next, 3: 1 volume of acetonitrile and toluene from the graphite carbon side of a mini column (trade name “InertSep GC / NH ₂ ” of GL Science Co., Ltd.) in which 500 mg of graphite carbon and 500 mg of aminopropylsilylated silica gel are stacked and packed. 10 mL of solvent mixed in proportion was injected and the effluent was discarded. And after inject | pouring a sample solution from the graphite carbon side of this mini column, 20 mL of solvent which mixed acetonitrile and toluene in the volume ratio of 3: 1 was inject | poured, and all the eluates were ensured. The eluate was concentrated to 1 mL or less at 40 ° C. or less, and 10 mL of acetone was added thereto, and the mixture was again concentrated to 1 mL or less at 40 ° C. or less. The concentrate was dissolved again by adding 5 mL of acetone, and then the solvent was removed. The residue at this time was dissolved in acetone so that the volume was exactly 1 mL, and an analytical sample having a sample concentration of 4 g / mL was obtained. The time required for the preparation of the analysis sample was 110 minutes from the time when the work of adding acetonitrile after the mixing of the food material B and the pesticide standard solution was started. In this analysis sample, three kinds of phenanthrene d-10, anthracene d-10 and 9-bromoanthracene were added as injection spikes so that the concentration was 100 ppb.

Comparative Example 3 (Preparation of analytical sample by QuEChERS method according to European standard EN15662)
In the second centrifuge tube, 150 mg of magnesium sulfate, 25 mg of ethylenediamine-N-propylsilylated silica gel (trade name “InertSep PSA” from GL Sciences Inc.) and 7.5 mg of graphite carbon (trade name “Grafted Carbon Black” from Waters) In addition, an analytical sample having a sample concentration of 1 g / mL was prepared from the food sample B in the same manner as in Comparative Example 1 except that 1 mL of the liquid layer collected from the first centrifuge tube was added thereto. The time required for the preparation of this analytical sample was 30 minutes from the start of the operation of adding acetonitrile to the first centrifuge tube in which the food sample B and the like were taken.

Analytical samples prepared in each Example and each Comparative Example were analyzed under the following conditions using evaluation GC / MS (trade name “Trace GC / PolarisQ” of Thermo Fisher Scientific Co., Ltd.) The recovery rate was determined. The results are shown in Table 1A, Table 1B and Table 1C. FIG. 8 shows a GC / MS SCAN chromatogram of the analytical sample obtained in Example 1 and Comparative Example 1. FIG. 9 shows a GC / MS SCAN chromatogram of the analytical sample obtained in Example 2 and Comparative Example 2. FIG. 10 shows GC / MS SCAN chromatograms of the analytical samples obtained in Example 2 and Comparative Example 3, respectively.

column:
5% phenyl-methyl silicon, 0.25mm inner diameter, 30m length, 0.25μm film thickness
Column temperature:
50 ° C (1 minute) -30 ° C / minute-125 ° C (0 minute) -5 ° C / minute-200 ° C (0 minute) -10 ° C / minute-300 ° C (11 minutes 30 seconds)
Inlet temperature: 220 ° C
Carrier gas: Helium ionization mode (voltage): EI (70 eV)

  Table 2 shows the results of determining the ratio of the pesticide peak number with a recovery rate of 70 to 120% and the pesticide peak number with a recovery rate of 70 to 120% with respect to the total number of pesticide peaks.

  When Example 1 was compared with Comparative Example 1, the number of pesticides that yielded 70 to 120% recovery was almost the same. However, according to FIG. 8, Example 1 has fewer contamination peaks than Comparative Example 1, and the purification effect is higher.

  When Example 2 and Comparative Example 2 were compared, the number of pesticides at which a recovery rate of 70 to 120% was obtained was almost the same. However, according to FIG. 9, Example 2 has fewer contamination peaks than Comparative Example 2 and has a higher purification effect.

  When Example 2 was compared with Comparative Example 3, the number of pesticides that yielded a recovery rate of 70 to 120% was higher in Example 2. Moreover, according to FIG. 10, Example 2 has fewer contamination peaks than Comparative Example 3, and the purification effect is higher.

DESCRIPTION OF SYMBOLS 1 Analytical sample preparation kit 10 Centrifuge tube 100 1st unit 103 Adsorption layer 200 2nd unit 203 Separation membrane 300 3rd unit 303 Purification layer L Mixture S Solvent for extraction

Claims (12)

A method for preparing a sample used for analyzing pesticide residues in foods,
Step 1 of extracting the residual pesticide from the food using a water-soluble first solvent and mixing the resulting extract with water to prepare a mixture;
Using a separation membrane that can be used as a nanofiltration membrane, an ultrafiltration membrane or a microfiltration membrane, and filtering the mixture to obtain a filtrate; and
Passing the filtrate through an adsorbent capable of adsorbing the residual agricultural chemical in the filtrate; and
After step 3, a step 4 of passing a second solvent capable of extracting the residual agricultural chemical through the adsorbent;
Of a sample for analysis of residual pesticides containing   The method for preparing a sample for analysis of residual agricultural chemicals according to claim 1, wherein Step 2, Step 3 and Step 4 are performed by applying a centrifugal force to the mixed solution, the filtrate and the second solvent, respectively.   The separation membrane includes polysulfone resin, polyether sulfone resin, polyvinylidene fluoride resin, aromatic polyamide resin, cellulose acetate resin, polytetrafluoroethylene resin, polyamide resin, polyacrylonitrile resin, polyvinyl chloride-polyacrylonitrile copolymer. The method for preparing a sample for analysis of residual agricultural chemicals according to claim 1 or 2, which is an organic film or an alumina film made of a resin material selected from the group consisting of a resin and a polycarbonate resin.   The method for preparing a sample for simultaneous analysis of residual agricultural chemicals according to claim 3, wherein the organic film is plasma-treated or ozone-treated.   The adsorbent is at least one selected from the group consisting of styrene / divinylbenzene copolymer resin, divinylbenzene copolymer resin, cyanopropylated silica gel, phenylated silica gel, and octadecylated silica gel. 4. A method for preparing a sample for analysis of residual agricultural chemicals according to any one of 4 above.   6. The method according to claim 1, further comprising a step 5 of allowing the second solvent that has passed through the adsorbent to pass through a purified material capable of adsorbing the contaminant contained in the second solvent that has passed through the adsorbent. A method for preparing a sample for analysis of a residual pesticide as described.   The method for preparing a sample for analysis of residual agricultural chemicals according to claim 6, wherein step 5 is performed by applying a centrifugal force to the second solvent.   The purification material is at least one selected from the group consisting of ethylenediamine-N-propylsilylated silica gel, aminopropylsilylated silica gel, graphite carbon, octadecylated silica gel, and magnesium silicate. To prepare a sample for analysis of pesticide residues.   Acetonitrile or methanol is used as the first solvent, and at least one selected from the group consisting of acetone, toluene, dichloromethane and hexane is used as the second solvent and has a polarity lower than that of the first solvent. The method for preparing a sample for analysis of residual agricultural chemicals according to any one of claims 1 to 8, which is used. A kit for preparing a sample used for analyzing pesticide residues in foods,
A centrifuge tube with a closed bottom,
An adsorption layer capable of adsorbing the residual agricultural chemical contained in a mixed solution of a water-soluble solvent capable of dissolving the residual agricultural chemical and water that can be inserted into and extracted from the inside of the centrifuge tube and having liquid permeability. A first unit capable of partitioning the inside of the centrifuge tube up and down,
The inside of the centrifuge tube can be partitioned vertically above the adsorption layer by a separation membrane that can be used as a nanofiltration membrane, ultrafiltration membrane, or microfiltration membrane that can be inserted and removed from the inside of the first unit. A second unit,
A sample preparation kit for analysis of pesticide residues.   A purification layer that can be inserted into and extracted from the inside of the centrifuge tube and that can insert and extract the first unit therein, can adsorb contaminants mixed in the residual agricultural chemicals, and has a liquid permeability. The kit for preparing a sample for analysis of residual agricultural chemicals according to claim 10, further comprising a third unit capable of partitioning the inside of the centrifuge tube vertically between the bottom and the adsorption layer.   The kit for preparing a sample for analysis of residual agricultural chemicals according to claim 10 or 11, comprising two centrifuge tubes.

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