A method for detecting pesticide residues in tea

A detection method, Zhongnong's technology, applied in the field of analysis and detection, can solve the problems of increasing the chance of toxic and harmful substances, damaging the health of quality inspectors, and high work intensity, etc., to achieve accurate and reliable measurement results, easy operation, and high precision and reproducible effects

Active Publication Date: 2019-02-26
广西岑溪天晟茶业股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main disadvantages of the existing detection methods are: (1) When detecting multiple pesticide residues, multiple methods need to be selected: that is, one method is only suitable for detecting a certain pesticide, and the work intensity is high, the working time is long, and the efficiency is low; (2) The operation is cumbersome, the efficiency is low, and the chances of inspectors coming into contact with toxic and harmful substances increase, which will damage the health of quality inspectors

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] In an embodiment of the present invention, a method for detecting pesticide residues in tea leaves comprises the following steps:

[0021] (1) Pretreatment method: Weigh 1.0g test sample, pulverize, pass through a 150-mesh sieve, add 3mL of 0.05mol / L hydrochloric acid solution, ultrasonically treat for 20min, filter, and then wash the residue with 15mL of 0.05mol / L hydrochloric acid solution for 4 times , the solution was adjusted to pH 8.5 with 0.2mol / L sodium hydroxide solution, 1mg of anhydrous sodium acetate, 0.5mg of anhydrous magnesium sulfate and 3mL of acetic acid acetonitrile were added, and reacted in a water bath at 60°C for 1.5h. Chloromethane extraction, layering, and repeating the extraction twice, the combined extracts were dried over anhydrous sodium sulfate, spin-dried, and dilute to 1.0 mL with methanol for testing;

[0022] (2) Quantitatively analyze the pretreated samples by GC-MS to obtain the content of pesticide residues in the tea leaves. The me...

Embodiment 2

[0028] In an embodiment of the present invention, a method for detecting pesticide residues in tea leaves comprises the following steps:

[0029] (1) Pretreatment method: Weigh 1.0g of the test sample, pulverize it, pass through a 300-mesh sieve, add 8mL of 0.8mol / L hydrochloric acid solution, ultrasonicate for 40min, filter, and then wash the residue with 30mL of 0.8mol / L hydrochloric acid solution for 4 times , the solution was adjusted to pH 9.0 with 0.8mol / L sodium hydroxide solution, 4mg of anhydrous sodium acetate, 6mg of anhydrous magnesium sulfate and 40mL of acetic acid acetonitrile were added, reacted in a water bath at 80°C for 4h, after taking out and cooling, 50mL of chloroform was added Extraction, layering, and repeating the extraction twice, the combined extracts were dried over anhydrous sodium sulfate, spin-dried, and dilute to 1.0 mL with methanol for testing;

[0030] (2) Quantitatively analyze the pretreated samples by GC-MS to obtain the content of pestic...

Embodiment 3

[0035] In an embodiment of the present invention, a method for detecting pesticide residues in tea leaves comprises the following steps:

[0036] (1) Pretreatment method: Weigh 1.0g of the test sample, pulverize it, pass through a 200-mesh sieve, add 4mL of 0.1mol / L hydrochloric acid solution, ultrasonicate for 25min, filter, and then wash the residue with 20mL of 0.1mol / L hydrochloric acid solution for 4 times , the solution was adjusted to pH 8.5 with 0.3mol / L sodium hydroxide solution, 1.5mg of anhydrous sodium acetate, 1mg of anhydrous magnesium sulfate and 5mL of acetic acid acetonitrile were added, reacted in a water bath at 65°C for 2h, after taking out and cooling, 35mL of trichloro Extract with methane, separate layers, and repeat the extraction twice. The combined extracts are dried over anhydrous sodium sulfate, spin-dried, and dilute to 1.0 mL with methanol for testing;

[0037] (2) Quantitatively analyze the pretreated samples by GC-MS to obtain the content of pes...

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Abstract

The invention discloses a detection method for pesticide residues in tea leaves. The detection method includes the steps: weighing 1.0g of test samples, crushing and sieving the test samples, adding 0.05-0.8mol / L of hydrochloric acid solution, ultrasonically treating and filtering the test samples, washing residues by the aid of 0.05-0.8mol / L of hydrochloric acid solution, adjusting pH (potential of hydrogen) of the solution to be 8.5-9.0 by the aid of 0.2-0.8mol / L of sodium hydroxide solution, adding 1-4mg of anhydrous sodium acetate, 0.5-6mg of anhydrous magnesium sulfate and 3-40mL of acetic acid acetonitrile, performing reaction in water bath, taking out and cooling reaction products, adding trichloromethane, performing extraction and layering, repeating extraction twice, combining extraction liquid, drying the extraction liquid by the aid of anhydrous sodium sulfate, spin-drying the products, metering volume to 1.0mL by the aid of methyl alcohol, and waiting for testing; quantitatively analyzing pretreated samples by the aid of a GC-MS (gas chromatography-mass spectrometer) to obtain the content of the pesticide residues in the tea leaves. The detection method is high in sensitivity and stability, simple and convenient to operate, good in linear range and accurate and reliable in measuring result, has high accuracy and repeatability and can meet requirements for detecting the pesticide residues in the tea leaves, and sample adding recovery rate meets requirements.

Description

technical field [0001] The invention relates to the technical field of analysis and detection, in particular to a method for detecting pesticide residues in tea. Background technique [0002] Tea has a long history in China. Tea has a protective effect on brain cells. Tea can effectively delay brain degeneration and help maintain the health of brain blood vessels. Tea can also relieve fatigue, refresh oneself, improve eyesight, digest food, diuresis and detoxify, prevent dental caries, and eliminate bad breath. Tea is also an alkaline drink, which is beneficial to the correction of acidic constitution. Tea safety issues are directly related to people's life and health. In order to reduce the amount of pesticide residues in tea and improve the competitiveness of my country's tea products, the detection and analysis of pesticide residues is a very important part. The shortcomings of the existing detection methods mainly include: (1) When detecting multiple pesticide residues,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N30/02G01N30/06
CPCG01N30/02G01N30/06
Inventor 张根义胡彬张进吴念绮周朱晨
Owner 广西岑溪天晟茶业股份有限公司
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