A Multi-compound LC-MS/MS Method for the Screening of Mycotoxins in Grains

A method development and its validation are described for determining 31 selected Aspergillus, Fusarium, Penicillium, and Claviceps mycotoxins in small grain cereals (wheat, barley, oats). The method comprises an automated solvent extraction step followed by filtering, concentrating, and the analysis of the crude extract with liquid chromatographic-tandem mass spectrometric determination. The analytes included trichothecenes, zearalenone, fumonisins, moniliformin, enniatins, beauvericin, antibiotic Y, aflatoxins, ochratoxin A, mycophenolic acid, penicillic acid, and ergot alkaloids. These were separated in two consecutive chromatographic runs, both involving negative and positive electrospray ionization modes of mass spectrometry. The validation showed that the method performance was good for (semi-)quantitative work, limits of quantification varying between 1 and 1,250 mu g kg(-1), recoveries mostly between 51% and 122%, and repeatability being from 2% to 26% within day and from 14% to 28% between days (as relative standard deviation). A distinctive suppressive matrix effect, which depended on the analyte and the matrix, was observed but could be compensated for by using matrix-assisted standards. The developed multi-mycotoxin method permits simultaneous, simple, and rapid determination of several co-existing toxins and is ideal for, e.g., screening-type work or at concentration levels relevant in animal welfare.