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Determination method of residual quantity of flucythrinate pesticide in tea

A technology for the determination of cyfluthrin and its determination method is applied in the field of determination of the residual amount of cyfluthrin pesticide in tea, which can solve the problems of complex tea components and inability to fully meet the actual needs of tea pesticide residues, and achieve good results, The effect of simple extraction method and easy integration processing

Inactive Publication Date: 2016-03-09
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] The determination method of cyfluthrin pesticide residue in tea comprises the following steps:

[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 cyfluthrin: put 2 g of tea powder in a 50 mL centrifuge tube, accurate to 0.01 g, add 10 mL of deionized water, shake until the sample is fully infiltrated by water, let stand for 10 min, add 10 mL of petroleum ether and 1 mL of 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 cyfluthrin: Take 5 mL of the s...

Embodiment 2

[0035] The determination method of cyfluthrin pesticide residue in tea comprises the following steps:

[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 cyfluthrin: 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 cyfluthrin: Take 5 mL of the supernat...

Embodiment 3

[0043] The determination method of cyfluthrin pesticide residue in tea comprises the following steps:

[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 cyfluthrin: 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 cyfluthrin: Take 5 mL of the supernatant in ste...

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Abstract

The invention relates to a determination method of residual quantity of flucythrinate pesticide in tea. The determination method comprises the following steps: (1) sample preparation: drying tea, grinding and screening; (2) flucythrinate coarse extraction: placing tea powder into a centrifuge tube, wetting by adding water, adding petroleum ether and mixed interior label working fluid, vibrating and uniformly mixing, adding anhydrous magnesium sulfate, sodium chloride, sodium citrate, sodium hydrogen citrate and methylbenzene, uniformly vibrating, and centrifuging; (3) flucythrinate coarse extract purification: placing liquid supernatant into the centrifuge tube, adding anhydrous magnesium sulfate and a N-propyl ethylenediamine bonding solid phase adsorbing agent, uniformly vibrating, and centrifuging; (4) flucythrinate extraction: taking supernatant, and extracting, concentrating and filtering on a Florisil column by using a methylbenzene-isooctane mixed solution; (5) chromatographic detection. The extraction method provided by the invention is simple and good in effect, and the result integral processing is simpler and more accurate. The average recovery rate of the method is 93.21 percent to 103.75 percent, the relative standard deviation is 3.28 percent to 6.20 percent, the requirements are met, and accuracy and reliability are realized.

Description

technical field [0001] The invention belongs to the technical field of pesticide detection, and in particular relates to a method for determining the residual amount of cyfluthrin pesticide 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 o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N30/06G01N30/28
CPCG01N30/06G01N30/28
Inventor 周德志
Owner 周德志
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