Pretreatment method for detecting pesticide residues in fresh tea leaves

Abstract

The invention provides a pretreatment method for detecting pesticide residues in fresh tea leaves. The method comprises the following steps: selecting a dispersing agent which has high adsorptive property on pesticides such as organic chloride and pyrethroid, directly mixing and grinding the dispersing agent with a fresh leaf sample, so that the cell disruption degree of the sample is improved, and the sample is finally uniformly dispersed; obtaining a mixture in a half-dry state and taking the mixture as a filler, feeding the filler in a chromatographic column in which a certain amount of adsorbents and water removal agents are fed in advance, eluting by using a mixed organic solvent, concentrating an eluant, so that the eluant can be directly subjected to instrumental analysis. According to the method, the operations of extraction and purification of the sample are integrated, and loss of the measured substance caused by sample homogenization, precipitation, centrifugation, dissolution, emulsification and concentration is avoided. Moreover, the method is simple and convenient to operate, high in recovery rate, small in solvent consumption and low in analysis cost and is a green and environment-friendly sample pretreatment method.

Description

technical field [0001] The invention relates to the field of safety detection of agricultural products, in particular to a pretreatment method for detection of pesticide residues in fresh tea leaves by matrix solid-phase dispersion. Background technique [0002] Tea is recognized as the national drink of China and a cultural symbol that Chinese people are proud of. my country has become the world's largest tea-producing country. In 2012, the area of ​​tea gardens reached 2,385,200 hectares, and the output of tea reached 1.78 million tons. Tea drinking has become a living habit of most Chinese people, and tea has become an indispensable health drink and spiritual drink in social life. Moreover, with the popularization of people's healthy consumption concept, tea is being accepted, loved and pursued by more and more people. However, tea export has been facing serious non-tariff barriers in terms of quality and safety, involving heavy metals, pesticide residues and microorgan...

AI Technical Summary

Problems solved by technology

The classic sample pretreatment methods such as Soxhlet extraction and liquid-liquid extraction are cumbersome, time-consuming, consume a lot of organic solvents, and the extraction efficiency is low

Similarly, the current GB / T23205-2008 and GB / T23204-2008 national standard methods are aimed at finished tea leaves, and simultaneously determine 448 and 519 pesticide residues, all of which use acetonitrile high-speed homogenate extraction-solid phase extraction The column purification method also has the following problems: 1. It is complicated and time-consuming, generally takes 3.0-3.5 hours; 2. The cost is high, and the solid-phase extraction column used in the purification process is expensive (100-120 yuan / piece) , and can only be used once; 3. The toxic and harmful organic solvents are consumed in the pretreatment process (80-120 ml), which will cause harm to the environment and analysts

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