High Accuracy Measurement Technology And Development Of Reference Materials For Mycotoxins In Food

This paper focuses on the measurement technology of mycotoxins in food.Firstly,an accurate HPLC-DAD-MS/MS method for the value assignment of zearalenone(ZEN)is developed.Secondly,the certified reference material(CRM)of ZEN in acetonitrile was prepared for the first time.Thirdly,the HPLC-MS/MS method for the detection of mycotoxins in cereal is developed,which can be applied for value assignment of matrix CRMs of mycotoxins.The main works are listed as follows:1.Based on HPLC-QTRAP-MS and HPLC-DAD methods,accurate techniques for qualitative identification and quantitative measurement of main components and trace impurities in ZEN candidate material are developed.Two impurities,zearalenone(ZAN)and 7'-dehydrozearalenone(7'-DehydroZEN),are successfully identified the purity of ZEN was assigned by mass balance method and quantitative nuclear magnetic method.The value assignment results of the two methods are 997.5 mg/g and 993.5 mg/g,respectively.The quantification result of ZEN is determined by the average of the two methods and it is 995.5 mg/g.2.The CRMs of pure and solution of ZEN are prepared in this study.The stability of ZEN is studied in detail,mainly considering the influence of light,solvent,temperature and concentration.The result show that ZEN in acetonitrile solution is greatly affected by ultraviolet irradiation.After irradiating under 254 nm for 1 day,the content of main component was reduced by 52%,mainly converted into its isomer(from trans-to cis-).It can be found that after 1 day of irradiation,both the main component and the cis-ZEN continued to decrease.After 27 days of irradiation,the main component and the cis-ZEN reached a relatively stable state,accounting for 14.4%and 22.5%,respectively.However,ZEN pure materials are relatively stable under UV light.The experimental result also shows that ZEN in acetonitrile solution is relatively stable under visible light.With a brown bottling,most of the light is removed.By comparing the different solvents and temperature,it can be seen that it is more unstable in methanol solution.ZEN in acetonitrile solution is unstable at high temperature.The concentration has no effect on the ZEN in acetonitrile.Through the detailed study of the stability of ZEN,it provides a favorable basis for the preparation of GRM.Therefore,the GRM of ZEN solution use acetonitrile as a solvent.And it is best packed in a brown bottle and stored at-20? in the dark.The results of the CRMs of pure and solution of ZEN are 99.5±0.2%and 11.1 ?g/mL±2%,respectively.3.A simple and fast method to simultaneously determine aflatoxin B1,B2,G1,G2,ZEN,deoxynivalenol,ochratoxin A,fumonisin B1 in cereal by HPLC-MS/MS,is.optimized.For the first time,the spiking blank samples and natural contaminated samples are used to optimize the extraction solvent.Different extraction solutions are tested,with better performance for acetonitrile/water/formic acid.Sample preparation method is obtained by optimizing the soaking time of the sample,the weighing amount of the sample and the way of the internal standard.Mycotoxins have strong matrix inhibition in the grain matrix,and the matrix effect of their internal standard is quite different.Therefore,in the absence of a blank matrix,the quantitative results can be corrected using the 0 value to eliminate the effects of matrix effects.