Deoxynivalenol(DON) and its conjugate, DON-3-glucoside (D3G), are mycotoxins of significant concern in various cereal-based foods and beverages. The transformation of DON into D3G occurs from the field through food processing and is closely linked to Type II resistance of host plants against Fusarium infection. Accurate and precise quantification of DON and D3G is essential not only for food safety and regulatory compliance, but also for evaluating the efficacy of crop resistance strategies. Liquid Chromatography-Mass Spectrometry (LC-MS) emerged as a powerful analytical tool for the quantification of DON and D3G, especially since D3G cannot be detected by GC. However, in LC-MS analysis, the surrounding matrix, which comprises the complex mixture of compounds from grain extracts, exerts a significant influence on the accuracy and reliability of quantification. This matrix effect can lead to systematic biases in measurement; therefore, requires careful evaluation. In this study, we explored the critical issue of the matrix effect for the quantification of DON and D3G in wheat, barley, and malt using LC-MS. The goal of our study was to evaluate the matrix effect for the quantification of DON and D3G on LC-MS and to analyze the D3G transformation. The matrix effect (ME) was calculated with slopes of calibration curves from acetonitrile/water (84/16, v/v), barley and wheat extract, and malt extract. The MEs of wheat, barley and malt for DON were 86% and the MEs of barley/wheat and malt for D3G were 90 and 94% respectively. These results indicate significant ion-suppression for DON and D3G in these matrixes. Five samples of hard-red spring wheat and ten samples of two-row spring barley samples were analyzed for D3G transformation. The production of DON and the transformation of D3G varied between barley and wheat and varieties. We observed the molar ratios of D3G/DON increased after germination which significantly varied between samples; this underlines its significance in evaluating the resistance of barley and wheat to Fusarium infection, particularly in the context of type II resistance. 

Acknowledgements

U.S. Department of Agriculture under Agreement No. 59-0206-9-064 (cooperative project with USWBSI). James Gillespie, Thomas Studzinski, and Dr. Zhao Jin for assistance with this work. Dr. Gazala Ameen, and Dr. Shyam Solanki from SDSU for providing barley samples. Dr. Xuehui Li from NDSU for providing wheat samples.