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Method for detecting residue amount of fenvalerate pesticide in tea

A technology for pesticide residues and fenvalerate, which is applied in the field of detection of fenvalerate pesticide residues in tea, can solve the problems that cannot fully meet the actual needs of tea pesticide residues, complex tea components, etc., achieve good results, extract The effect of simple method and convenient integral processing

Inactive Publication Date: 2016-06-01
周德志
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the complexity of tea ingredients, theophylline, tea pigments, polyphenols, and lipids interfere with the determination, so the national testing standards cannot fully meet the actual needs of tea pesticide residues

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] A method for detecting fenvalerate pesticide residues in tea leaves, comprising the steps of:

[0028] (1) Sample preparation: put the tea leaves in an oven, keep them at 50°C for 2 hours, and dry them with a moisture content of 5%. Grind the samples and pass them through a 2mm sieve. Note that the grinding temperature should not exceed 50°C.

[0029] (2) Crude extraction of fenvalerate: put 2g of tea powder in a 50mL centrifuge tube, accurate to 0.01g, add 10mL of deionized water, shake until the sample is fully infiltrated by water, let stand for 10min, add 10mL of petroleum ether and 1mL Mix the internal standard working solution (mirex), shake vigorously for 1min, add 4g of anhydrous magnesium sulfate, 1g of sodium chloride, 1g of sodium citrate, 0.5g of disodium hydrogen citrate and 5mL of toluene, shake immediately by hand for 2min, and then Centrifuge at 4000rpm for 10min;

[0030] (3) Purification of the crude extract of fenvalerate: Take 5 mL of the supernatan...

Embodiment 2

[0035] A method for detecting fenvalerate pesticide residues in tea leaves, comprising the steps of:

[0036] (1) Sample preparation: put the tea leaves in an oven, keep them at 45°C for 3 hours, and dry them with a moisture content of 6%. Grind the samples and pass them through a 1mm sieve. Note that the grinding temperature should not exceed 50°C.

[0037] (2) Crude extraction of fenvalerate: put 3g of tea powder in a 50mL centrifuge tube, accurate to 0.01g, add 10mL deionized water, shake until the sample is fully infiltrated by water, let stand for 5min, add 12mL petroleum ether and 1mL Mix the internal standard working solution (mirex), shake vigorously for 2 minutes, add 4g of anhydrous magnesium sulfate, 1g of sodium chloride, 1g of sodium citrate, 0.5g of disodium hydrogen citrate and 5mL of toluene, shake immediately by hand for 2 minutes, and then Centrifuge at 3000rpm for 15min;

[0038] (3) Purification of the crude extract of fenvalerate: Take 5 mL of the superna...

Embodiment 3

[0043] A method for detecting fenvalerate pesticide residues in tea leaves, comprising the steps of:

[0044] (1) Sample preparation: put the tea in an oven, keep it at 55°C for 1 hour, and dry it with a moisture content of 4%. Grind the sample and pass it through a 3mm sieve. Note that the grinding temperature should not exceed 50°C.

[0045] (2) Crude extraction of fenvalerate: put 1g of tea powder in a 50mL centrifuge tube, accurate to 0.01g, add 10mL of deionized water, shake until the sample is fully infiltrated by water, let stand for 15min, add 8mL of petroleum ether and 1mL Mix the internal standard working solution (mirex), shake vigorously for 2 minutes, add 4g of anhydrous magnesium sulfate, 1g of sodium chloride, 1g of sodium citrate, 0.5g of disodium hydrogen citrate and 5mL of toluene, immediately shake for 3 minutes by hand, and then Centrifuge at 5000rpm for 5min;

[0046] (3) Purification of the crude extract of fenvalerate: Take 5 mL of the supernatant in st...

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Abstract

The invention relates to a method for detecting the residue amount of fenvalerate pesticide in tea. The method comprises the first step of preparing a sample, wherein tea is dried, ground and screened; the second step of rough extracting of fenvalerate, wherein tea powder is put into a centrifuge tube, water is added for wetting, petroleum ether and mixture interior label working solution are added, vibrating for mixing is conduced, anhydrous magnesium sulfate, sodium chloride, sodium citrate, sodium hydrogen citrate and toluene are added, uniform vibrating is conducted, and centrifugation is conducted; the third step of purifying rough extract of fenvalerate, wherein supernate is placed into the centrifuge tube, anhydrous magnesium sulfate and N-propyl ethylenediamine bonding solid-phase adsorbent are added, uniform vibrating is conducted, and centrifugation is conducted; the fourth step of extracting fenvalerate, wherein supernatant is taken, toluene-isooctane mixed solution is used for extraction, concentration and filtration on a Florisil column; the fifth step of detection of chromatography. The extracting method is simple, the effect is good, and result integrals are processed more easily, conveniently and accurately. According to the method, the average recovery rate ranges from 93.21% to 103.75%, the relative standard deviation ranges from 3.28% to 6.20%, requirements are met, and accuracy and reliability are achieved.

Description

technical field [0001] The invention belongs to the technical field of pesticide detection, and in particular relates to a method for detecting fenvalerate pesticide residues in tea leaves. Background technique [0002] Tea is a traditional economic crop that earns foreign exchange through export in my country. In recent years, with the widespread spread of the concept of green food, its inherent quality, hygiene and safety issues have increasingly attracted people's attention, and it has also become a technical barrier in international trade. In particular, the European Union promulgated a batch of maximum pesticide residue (MRL) standards in food on August 27, 2004, which included 168 tea pesticide residue standards. The number of tea testing items has increased a lot compared with the past, the maximum pesticide residue value has been greatly reduced, and the limit standards have become increasingly stringent. [0003] Pyrethroid insecticides are a class of broad-spectru...

Claims

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Application Information

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IPC IPC(8): G01N30/02G01N1/28G01N1/34
CPCG01N30/02G01N1/28G01N1/34G01N2030/027
Inventor 周德志
Owner 周德志
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