Quantitation of Mycotoxins in Four Food Matrices Comparing Stable Isotope Dilution Assay (SIDA) with Matrix-Matched Calibration Methods by LC-MS/MS.

Mycotoxins are big concerns in food safety. Analytical methods are important for the evaluation of mycotoxins in different food commodities. In this study, stable isotope dilution assay (SIDA) was compared with a matrix-matched calibration method for the quantification of mycotoxins in four different commercially available commodities and two reference materials. All samples were extracted with water-acetonitrile (50+50, v/v), followed by filtration and LC-tandem MS analysis. SIDA calibration accuracies ranged from 78.6 to 112% with relative SDs (RSDs) ≤16% across all four matrices. The majority of the recoveries across all matrices ranged from 70 to 120% with RSDs <11%. Of the four mycotoxins in the reference materials analyzed, only three had C-internal standard (IS), whereas the fourth was quantified using a closely eluting C-IS for a different mycotoxin. Mycotoxins paired with their corresponding C-IS had accuracies >90%, whereas accuracies for the mismatched mycotoxin/C-IS were <14%. When C-IS are not available, matrix-matched calibration was also evaluated as an alternative to quantitating target mycotoxins. The use of C-IS is the best way to dynamically account for prevalent matrix effects, but matrix matching provides a viable alternative. The study compared SIDA and matrix-matched calibration methods in terms of recovery, efficiency, advantages, and limitations for LC-MS based mycotoxin analysis.