The latest research results of the team of researcher Wu Aibo, Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences

Researcher Wu Aibo team of Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences: establishment and verification

Simultaneous determination of four aflatoxins in fermented tea by one-step purification method combined with liquid chromatography-tandem mass spectrometry

Researcher Wu Aibo's team from Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences published a research article titled "Development and Validation of the One-step Purification Method Coupled to LC-MS/MS for Simultaneous Determination of Four Aflatoxins in Fermented Tea" in Food Chemistry This study aims to establish a low-cost, simple-to-use liquid chromatography-tandem mass spectrometry method to simultaneously detect the content of four aflatoxins in fermented tea by optimizing the pretreatment process of fermented tea.

Aflatoxin B ₁ is the most concerned potential chemical pollutant during the production and storage of fermented tea.

1 Introduction

Tea leaves are divided into green tea, white tea, yellow tea, oolong tea, black tea, and dark tea according to the degree of fermentation of production and processing, and they have different characteristic chemical substances.

In recent years, liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been widely used to determine aflatoxins in various food matrices (such as fruits, vegetables, grains and their products, Chinese herbal medicines, etc.

With the development of various sample preparation methods, the sample detection process is gradually optimized.

This study established a one-step purification method for tea matrix based on carboxylated carbon nanotubes, aiming to establish a simple and efficient liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the analysis of aflatoxins in fermented tea , Achieve low detection limit and high sensitivity.

2.

Tea is a dry and loose base that is different from other food bases.

In order to optimize the mass spectrometry parameters, we use a full scan method to monitor aflatoxins, with m/z ranging from 0 to 500 to obtain suitable precursor ions.

3.

According to the guidelines of the EU document (SANTE/126823/2019), the analytical parameters of the developed LC-MS/MS method were verified under optimized conditions.

I ^a _{: Incidence}

ND ^b _{: not de tectable}

_{n : number of positive samples}

_{N : number of total samples}

4 Conclusion

For the first time, a new method for the analysis of aflatoxins in fermented tea with one-step purification method combined with LC-MS/MS was established.
This method is based on the improvement of QuEChERS sample preparation, by optimizing the extraction process, and using a self-made purification tube (MWCNTs-COOH, HLB, SG) to purify the tea co-extract.
According to EU guidelines, this method has been successfully verified on a tea matrix containing 4 different levels of aflatoxin, and has been applied to the analysis of 20 commercially available Pu'er teas.
No aflatoxin was detected in the tea, or the concentration of aflatoxin-positive samples was lower than the relevant limit standard.
Compared with the traditional sample pretreatment method, this method has the advantages of low cost and simple operation under the premise of ensuring the recovery rate and the limit of quantification, and further improves the ease of use and versatility of the method.
The establishment of this method provides a targeted method for the specific analysis of a large number of traces of mycotoxins or other chemical substances in complex matrices.

The research was supported by the National Key Research and Development Program (2018YFC1604403).

Corresponding author's profile:

Wu Aibo, Ph.
D.
, researcher and doctoral supervisor of the Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, leader of the food safety and mycotoxins research group, has long been engaged in the detection of mycotoxins in food, safety evaluation and pollution control research.
He is currently a member of the National Expert Committee on Food Safety Risk Assessment, a member of the Microbial Toxin Professional Committee of the National Society of Microbiology, a member of the Food Hygiene Branch of the Chinese Preventive Medicine Association, and an editorial board member of "Food Control" and "Toxins".
Worked in collaboration with Wageningen University in the Netherlands, Ghent University in Belgium, and Fa Leuven University.
In the past 5 years, Springer has published an English academic monograph "Food Safety & Mycotoxins" (2019, all ten chapters are corresponding authors), and 28 research papers have been published in Anal Chem, Food Control, Food Chemistry and other journals as correspondent/co-corresponding authors He cited more than 1,500 times.
Presided over more than 10 national/local scientific research projects.
The results were successfully transformed and applied to the government and large-scale enterprise food safety supervision.
He won the Outstanding Youth Award of the Chinese Food Science and Technology Society (2017), and the National Association for Analysis and Testing Science and Technology Progress Award.
Award (2016, 2nd).

Introduction of the first author:

Zhou Haiyan, from September 2014 to June 2018, studied food science and engineering at the School of Food Science and Engineering, Gansu Agricultural University; in September 2018, entered the Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, and studied in the Food Safety and Mycotoxin Research Group Master's degree; 2020 Ph.
D candidate in Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences; Research direction: Food safety.

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