A Method for Simultaneous Determination of 28 Kinds of Pesticide Residues in Green Tea by Gas Chromatography-Triple Quadrupole Secondary Mass Spectrometry

Abstract

The invention discloses a method for simultaneously measuring 28 kinds of pesticide residues with gas chromatography-triple quadrupole tandem mass spectrometry. The method includes the steps of A, sample pretreatment, namely weighing fresh tea leaf powder and pouring the same into a centrifuge tube, adding 1% of an acetonitrile acetic acid solution, adding NaCl after homogenated extraction, and performing full shock blending and centrifugal stratifying prior to taking clear liquid on the upper layer for standby use; B, purification and interior label treatment, namely pouring the clear liquid on the upper layer into the centrifuge tube, purifying the clear liquid with QuEChERS and adding an interior label solution, and taking supernate for standby use after whirlpools shock and centrifugation; C, mass spectrometric measurement, namely subjecting the supernate in the step B to qualitative and quantitative analysis with the gas chromatography-triple quadrupole tandem mass spectrometry. With the method, the problem about measurement blank of the pesticide residues of tea leaves is solved, and the method has the advantages of high flexibility, good selection and high repeatability and accuracy, the 28 kinds of pesticide residues in the green leaves can be measured simultaneously, and the method is specially suitable for measurement analysis for large amount of samples.

Description

technical field [0001] The invention relates to a method for simultaneously measuring 28 kinds of pesticide residues in tea greens by using gas chromatography-triple quadrupole secondary mass spectrometry, and belongs to the technical field of tea raw material-pesticide residue detection in tea greens. Background technique [0002] In recent years, Guizhou Province has given full play to its advantages in resources, intensified the adjustment of agricultural structure, and focused on tea and other advantageous and characteristic industries. In 2015, the province's tea planting area was 6.89 million mu, ranking first in the country, with a comprehensive output value of nearly 10 billion yuan. The quality and safety of tea is an important basis for ensuring the sustainable development of the tea industry in Guizhou Province. Green tea is the raw material for tea production. In particular, the green tea raw materials of some tea companies in Guizhou Province mainly come from th...

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Problems solved by technology

[0003] At present, only the detection of pesticide residues in tea leaves is carried out in tea processing in my country, and the main methods used are GB / T5009-103, GB / T 5009-110, GB / T 5009-19, GB / T 5009-20, GB / T 5009 -146, GB / T 5009-105 and other methods, there is no detection method for pesticide residues in green tea, resulting in a blank detection of pesticide residues in green tea, increasing the detection risk of pesticide residues in finished tea

In particular, when tea greens, raw materials of tea, are roasted into finished tea leaves, if there are unstable pesticides that are easily hydrolyzed and decomposed in the tea greens, they may be hydrolyzed or decomposed by heat during the roasting process, and converted into other harmful pesticides. Substances continue to remain on tea leaves, increasing the risk of health hazards for consumers and difficulty in monitoring

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