Preparation method of plant-derived matrix for pesticide residue detection

Abstract

The invention relates to a preparation and storage method of a matrix for determining residual quantity of pesticide and metabolite thereof in plant-derived food. The matrix is prepared by blow-drying an acetonitrile extracting solution of a plant, forms a film at the bottom of a glass tube or is sprayed on the surface of a glass plate, and is filled with nitrogen for protection. At present, matrix standard liquid needs to be prepared for quantification during detection of most pesticide residues, related commercial products are not found in the market, and a self-made matrix in a laboratory is needed. Botanical products such as commercially available vegetables and fruits may have pesticide residues, and a blank matrix is difficult to obtain. The invention aims to make up the market blank, and provides a preparation and storage method convenient for mass production of substrates. The method can be used in the field of determination of residual quantity of pesticides and metabolites thereof in plant-derived food. The matrix is a biological material, the preparation method is simple and easy to implement, and a finished product is convenient to use, easy to store and capable of being commercially applied.

Description

Technical Field

[0001] The present invention relates to a method for preparing and storing a matrix for determining the residual amount of pesticides and their metabolites in plant-derived foods. The matrix is ​​formed into a film at the bottom of a glass test tube, and the matrix is ​​a biological material, which is convenient to store and can be commercially applied. Background Art

[0002] At present, most pesticide residue tests require the preparation of matrix standard solutions for quantification. No relevant commercial products have been found on the market, so laboratories need to make their own matrices. Commercially available vegetable and fruit products and other plant-derived products may have pesticide residues, and it is difficult to obtain blank matrices. Especially when the laboratory has not conducted relevant tests, there are many corresponding matrices that need to be prepared before the test, and a lot of manpower, material resources, and financial resources are needed to find blank matrices that do not contain pesticides. Summary of the invention

[0003] The present invention aims to fill the gap in the market and provide a method for preparing and storing a matrix for determining the residual amount of pesticides and their metabolites in plant-derived foods. The method is simple and easy to implement, and the finished product is easy to use and store.

[0004] The present invention is achieved through the following technical solutions: The plant-derived matrix of the present invention is prepared by drying the acetonitrile extract of the plant, and is packed in nitrogen-filled packaging for long-term storage.

[0005] The method for preparing the plant-derived matrix of the present invention is as follows: Select plant-derived foods without pesticide residues, dry and crush them, and calculate the water content of the plants.

[0006] Add acetonitrile to the dried and crushed plant-derived food for high-speed homogenization. After mixing evenly, add magnesium sulfate, ethylenediamine-N-propyl silane silica gel (PSA, 40 μm~60 μm), octadecylsilane bonded silica gel (C18, 40 μm~60μm), and graphitized carbon black (GCB, 40 μm~120 μm). Continue to homogenize and mix evenly, let stand to separate layers, extract the supernatant, and spray it on the surface of a glass plate to form a film; or centrifuge the mixture, extract the supernatant, dispense it into glass tubes, and blow dry with nitrogen to form a film covering the bottom of the tube.

[0007] The prepared glass tubes are grouped in groups of 7, tied with rubber bands, packed in plastic bags, and sealed after filling with nitrogen; or the prepared glass tubes are sealed individually and packed in boxes, or without outer packaging. The coated glass plate is inserted into a box with a groove and filled with nitrogen for protection. DETAILED DESCRIPTION

[0008] The following examples will help to understand the present invention, but they are not intended to limit the present invention. Example

[0009] Spinach matrix preparation method Select whole spinach without pesticide residues, remove the roots and weigh 10 kg, dry and crush, put it into a tank, add 10 L acetonitrile, and homogenize at 15 000 r / min for 5 min. Then add 1.5 kg magnesium sulfate, 0.25 kg ethylenediamine-N-propyl silane silica (PSA, 40 μm-60 μm), and 0.025 kg graphitized carbon black (GCB, 40 μm-120 μm). The slurry is mixed and dispensed into centrifuge tubes. Centrifuge at 4 500 r / min for 5 min, extract 2 mL of supernatant into 5 mL round-bottom glass tubes, and blow dry with 1 L / min nitrogen to form a film covering the bottom of the tube. Example

[0010] Green tea leaf matrix preparation method Green tea leaves without pesticide residues were selected and crushed to weigh 10 kg. The leaves were put into a tank and 75 L of acetonitrile was added. The mixture was homogenized at 15,000 r / min for 5 min. Then 7.5 kg of magnesium sulfate, 2.5 kg of ethylenediamine-N-propyl silane silica gel (PSA, 40 μm-60 μm), 2.5 kg of octadecylsilane bonded silica gel (C18, 40 μm-60 μm), and 1.25 kg of graphitized carbon black (GCB, 40 μm-120 μm) were added. The mixture was allowed to stand for stratification. The supernatant was extracted and sprayed on the surface of a glass plate to form a film. 1 mL of supernatant was applied to each side, and each glass plate was sprayed on two sides. Example

[0011] Matrix finished product packaging and storage The prepared glass tubes with a matrix coating on the bottom are arranged in groups of 7, 7 for stability, tied with rubber bands for fixation, packed in plastic bags, sealed after being filled with nitrogen, and stored at room temperature. Example

[0012] Finished matrix products are packaged and stored in boxes The glass plate with matrix coating is inserted into a box with grooves. The matrix coating does not contact any packaging materials. There is a gap between the plates. After the lid is closed, gently shake the plate without obvious shaking. The plates do not contact each other. After filling with nitrogen, seal with aluminum foil, cover with lid, and store at room temperature.

Claims

1. A method for preparing a plant-derived matrix for detecting pesticide residues, characterized in that The extract is prepared by blowing the acetonitrile extract of the plant to dryness, forming a film on the bottom of a glass tube, or spraying it on the surface of a glass plate, and filling it with nitrogen for protection; the extraction method is: selecting plant-derived food without pesticide residues, drying and crushing it, and adding acetonitrile for high-speed homogenization extraction.

2. The packaging feature is that the prepared bottom-coated glass tubes are grouped in groups of 7, tied with rubber bands, packed in plastic bags, and sealed after filling with nitrogen; or the prepared glass tubes are sealed individually and packed in boxes, or there is no outer packaging; the coated glass plate is inserted into a box with a groove and filled with nitrogen for protection.