Advanced LC-MS-based methods to study the co-occurrence and metabolization of multiple mycotoxins in cereals and cereal-based food

Abstract

Liquid chromatography (LC) coupled with mass spectrometry (MS) is widely used for the determination of mycotoxins in cereals and cereal-based products. In addition to the regulated mycotoxins, for which official control is required, LC-MS is often used for the screening of a large range of mycotoxins and/or for the identification and characterization of novel metabolites. This review provides insight into the LC-MS methods used for the determination of co-occurring mycotoxins with special emphasis on multiple-analyte applications. The first part of the review is focused on targeted LC-MS approaches using cleanup methods such as solid-phase extraction and immunoaffinity chromatography, as well as on methods based on minimum cleanup (quick, easy, cheap, effective, rugged, and safe; QuEChERS) and dilute and shoot. The second part of the review deals with the untargeted determination of mycotoxins by LC coupled with high-resolution MS, which includes also metabolomics techniques to study the fate of mycotoxins in plants.

Keywords: Fungal secondary metabolites; Liquid chromatography–high-resolution mass spectrometry; Liquid chromatography–tandem mass spectrometry; Metabolomics; Validation.

Fig. 1

Chemical structures of the most important mycotoxins belonging to the group of Aspergillus toxins (aflatoxin B₁, alfatoxin G₁, ochratoxin A, patulin), Fusarium toxins (deoxynivalenol, T-2 toxin, zearalenone, fumonisin B₁, beauvericin, enniatin A), Alternaria toxins (alternariol), ergot alkaloids (ergotamine), and Penicillium toxins (patulin, ochratoxin A)

Fig. 2

An example of the z score compilation obtained by the multimycotoxin liquid chromatography–tandem mass spectrometry method in proficiency testing organized by the Bureau Interprofessionnel des Études Analytique (BIPEA). Green lines borders of acceptable range of z scores, red lines borders of questionable range of z scores, area outside red lines unacceptable values

Fig. 3

An overview of use of liquid chromatography (LC)–mass spectrometry (MS) instruments in studies focused on mycotoxin analysis published between 2012 and 2016. LC–MS/MS covers studies using instruments equipped with triple quadrupole, quadrupole–linear ion trap, and ion trap mass analyzers; LC–high resolution MS (HRMS)/MS covers studies using instruments equipped with quadrupole–time of flight or quadrupole–orbital ion trap mass analyzers

Fig. 4

Metabolism of deoxynivalenol (DON) in wheat. Sample treated with 1:1 native DON and ¹³C-labeled DON (tracer). Deoxynivalenol 3-glucoside (DON-Glc) was found as a major metabolite. Mass spectrometry (MS) scan of DON and ¹³C-labeled DON (A). Extracted ion chromatogram of DON (B). Extracted ion chromatogram of DON-Glc (C). MS scan of DON-3-Glc and ¹³C-labeled DON-Glc (D). Extracted ion chromatogram of ¹³C-labeled DON (E). Extracted ion chromatogram of ¹³C-labeled DON-Glc (F)