Analytical Method of Multi-Mycotoxins in Table-Ready Foods for a Total Diet Study Using Stable Isotope Dilution Liquid Chromatography-Tandem Mass Spectrometry.

Determining the multi-mycotoxins present in table-ready foods is necessary for a total diet study. However, so far, most methods of analyzing multi-mycotoxins apply to raw foods. Therefore, a reliable method for analyzing multi-mycotoxins in table-ready foods is needed. We developed and validated methods of multi-mycotoxin analysis that employed stable isotope dilution with LC-tandem MS (LC-MS/MS) using two representative matrices. Samples were fortified with [C]-labeled mycotoxins as internal standards and extracted with 50% acetonitrile in water for high-carbohydrate foods and 3% formic acid in acetonitrile for high-protein and/or high-fat foods, cleaned up with -hexane and the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method, and followed up by LC-MS/MS. Validation of the methods was performed, and the results were as follows: the correlation coefficient, ², was 0.99; method detection limit, 0.01-2.4 μg/kg; recoveries, 83.6-114%; precision, 0.8-10 (intraday) and 3.1-22% (interday); interlaboratory reproducibility, ≤15%; and uncertainty, 3.5-19%. The applicability of the methods was evaluated by analyzing table-ready foods spiked with standards. These methods were successfully evaluated and deemed appropriate for determining the multi-mycotoxins in table-ready foods. This work demonstrates that stable isotope dilution with LC-MS/MS can be effectively used to analyze multi-mycotoxins simultaneously in a total diet study.