Development of a rapid multi-mycotoxin LC-MS/MS stable isotope dilution analysis for grain legumes and its application on 66 market samples

Abstract

Mycotoxin contamination is a well-known problem in grains, nuts, and oilseeds. Similarly, grain legumes (pulses) are affected by fungal infections and, consequently, the formation of mycotoxins as well. However, only little data on mycotoxin occurrence exists for this commodity and only few validated quantification methods for multi-mycotoxin analysis have been reported. In order to effectively assess contamination levels for grain legumes, a high performance liquid chromatography method coupled to tandem mass spectrometry (LC-MS/MS) was developed, validated for the matrix soybean and tested with further grain legumes. The method implements a QuEChERS-like extraction and a stable isotope dilution assay (SIDA) to facilitate the quantification of nine different mycotoxins (aflatoxins B1, B2, G1, G2, ochratoxin A, deoxynivalenol, zearalenone, T-2 toxin, HT-2 toxin). In a non-representative market sample screening, 66 samples of dry grain legumes from the Dutch and the German market were measured. Incidentally, high levels of ochratoxin A were detected in white beans and green peas with 157 μg/kg and 49.4 μg/kg, respectively. In addition, T-2 toxin was detected in one black lentil sample. A multi-mycotoxin method as a tool for rapid collection of data on mycotoxin levels in grain legumes may proof valuable for evaluating exposure and fate of mycotoxins during the whole value-added (feed and food) chain.