Research On Precise Detection Technology Of Mycotoxins In Grains And Their Products

Objective: In this research,a method for the determination of mycotoxins in grains and their products using ultra-high performance liquid chromatography(UHPLC)-high resolution mass spectrometry(HRMS)was proposed.1.A method based on QuEChERS and HRMS method for the determination of multiple mycotoxins in flour was proposed;2.A method based on multiple characteristic structural fragments and HRMS to discover and identify unknown mycotoxins in grains and their products.Methods:1.The 19 mycotoxins in the fully hydrated flour were extracted with 0.1%formic acid acetonitrile solution.The water and impurities in the samples were removed with the QuEChERS extraction kit and QuEChERS dispersive SPE.The separation was performed on a ZORBAX Eclipse Plus C18 column and quantified by external standard method.Mass analysis was performed in positive ion with the scan mode of Full MS/ddMS2(Top N).2.The same pretreatment and analysis methods were used to extract and detect mycotoxins and their derivatives in grains and their products.The fragmentation pathways of four types of mycotoxins were elucidated and the multiple characteristic structure fragments were screened out through the combination of fragmentation pathways and common fragments of the same type of mycotoxins.The screening of multiple characteristic structure fragments was performed to screen samples for the presence of possible structural analogues of mycotoxins in grains and their products.Results:1.To establish an UHPLC-HRMS method for the determination of 19 mycotoxins in flour.The linear relationship of the method was good in the concentration range of 1-200 μg/kg,and the correlation coefficients R2 were all greater than 0.99.The limit of detection(LOD)was 0.5～2.0 g/kg and the limit of quantification(LOQ)was 1.5～6 g/kg.The average recoveries of this method were 71.4% ～ 98.7%,and the intra-day and interday precisions ranged from 0.2% to 7.4%.2.To establish a method for the detection and identification of unknown mycotoxins in grains and their products based on multiple characteristic structure fragments and HRMS.The proposed approach proved to be valid to discover and identify 5 new structural analogues of mycotoxins and the mass accuracy is less than 5ppm.Conclusion: 1.The QuEChERS and HRMS method for the determination of mycotoxins in flour has good extraction effect,high accuracy and high resolution,and is suitable for the determination and analysis of mycotoxins in flour;2.The detection and identification of unknown mycotoxins in grains and their products based on based on multiple characteristic structure fragments and HRMS is simple,rapid and accurate,which is suitable for the discovery and identification of unknown mycotoxins in grains and their products.