Various food commodities are vulnerable to different types of fungal pathogens and could be contaminated with differential classes of mycotoxins as a result. It is ideally to implement a generic method for simultaneous determination of multi-mycotoxins in different food matrices or agricultural products.
In this study, a simplified sample preparation procedure and a reliable LC-MS/MS analytical method was developed for comprehensive measurement of 37 regulated and emerging mycotoxins, including five Alternaria toxins, six major ergot alkaloids, and their corresponding epimers. Four different food matrices (baby wheat cereal, peanut, tomato puree, and blended flour) were chosen for method validation to demonstrate the applicability of this analytical method to a wide range of food types. Sample extraction was performed using a formic acid-acidified 80:20 acetonitrile:water solution followed by extract dry down and reconstitution in a 50:50 water:methanol solution for injection analysis on a Biphenyl LC column. Chromatographic analysis was performed using MS-friendly acidic mobile phases and completed with a short 11-minute cycling time for proper separation of ergot alkaloid epimers. Method accuracy and precision was evaluated by fortification of food samples at three different levels. Accurate quantification was achieved using matrix-matched calibration standards at the range of 0.4 to 400 μg/kg.
The recoveries of all mycotoxins (except citrinin) in fortified samples were from 70% to 120%, and the relative standard deviation was less than 20%. The established workflow was simple and fast for multi-mycotoxin determination with a unique benefit of simultaneous analysis of Alternaria toxins and ergot alkaloids. Furthermore, a novel inert Biphenyl LC column demonstrated the high degree of Non-Specific Binding (NSB) that occurs between the column’s stainless-steel hardware and certain mycotoxins.
The implementation of the inert column offers a robust and improved chromatographic performance as it mitigates the NSB for highly adsorptive analytes (e.g., fumonisins, aflatoxins, and tenuazonic acid) leading to better sensitivity and peak shapes without the need of mobile phase additives or sample passivation.
