Study On Detection Of Main Mycotoxins And The Law Of Content Change Of Mycotoxins At Different Storage Conditions In Coix Seed

Mycotoxins are toxic secondary metabolites produced by fungi, which have a strong toxicity to human and animal liver,even causing liver cancer. The traditional Chinese medicine, bread and feed may be infected by fungi and mycotoxins during their growth in fields, harvest, storage and processing. Among the mycotoxins identified to date, the mycotoxins which are related with the health of people contain aflatoxin(AF), zearalenone(ZON), ochratoxin, and so on, they will constitute risk for human and animal health by ingesting contamined cereal crops.According to lots of document in demolition blasting, edible Chinese herbal Coix seed was infected by AF or ZON frequently. Then according to the detection method and limited standard deficiency of ZON, and multiple mycotoxins analysis method deficiency, choosing Coix seed as research object, screening different methods to clean-up, this thesis researched simultaneous detection of ZON and a-ZOL, and simultaneous detection of AF, ZON and its derivatives, provides a reference for simultaneous detection of various mycotoxins in the traditional Chinese medicine. At the meanwhile, in order to decreasing and controling the contamination of mycotoxins, this thesis preliminary studied the law of content change of mycotoxins in Coix seed at different storage conditions.The main contents and conclusions were as follows:1. Through campering the clean-up efficts of different solid phase extraction columns, High performance liquid chromatography and fluorescence detection method was established to analyze ZON, a-ZOL in Coix seed. The recoveries of analytes were from83.2%for a-ZOL, while86.1%for ZON, the relative standard deviations were below6.68%. The detection limits of a-ZOL and ZON were15and13μg/kg, respectively. The method used graphitized carbon black solid-phase extraction column to process ZON and a-ZOL in Coix seed, based on high-performance liquid chromatography. Compared to materials and instruments as immunoaffinity columns, mass spectrometry, and so on, it was showed that the method was saving more resources and easier to generalize.2. Through campering the clean-up efficts of different solid phase extraction columns, High performance liquid chromatography and fluorescence detection with online post-column photochemical derivatization method was established to analyze aflatoxin B1; B2, G1, G2, ZON, α-ZOL and β-ZOL in Coix seed. The recoveries of analytes were from85.8%～97.0%and the relative standard deviations were below11.93%. Campering with the method of Chinese Pharmacopoeia, this method could simultaneously determine seven mycotoxins. Each of the10samples were processed and analyzed according to the method described above. The results showed that, all the samples were contaminated with aflatoxin B1,7samples were contaminated with ZON at levels ranging44.71～931.07μg/kg. The probability of contamination caused by aflatoxin B1and ZON in Coix seed at the same time is high. The other mycotoxins were not found.3.Through the simulations of high temperatrue and humidity, low temperatrue and enclose, ventilation and cool which is requirementsn of Pharmacopoeia, using established analytical methods, this thesis investigated the impact of different storage conditions to mycotoxins in Coix seed. The results showed that the storage conditions was very important to the mycotoxins Coix seed. The normal Coix seed could contain a lot of mycotoxins; AF and ZON increaseed most in storage in ventilation and dry. and the mechanism of accumulation of toxins for Coix seed requires further study.