Multimycotoxin analysis of crude extracts of nuts with ultra-high performance liquid chromatography/tandem mass spectrometry

A reliable, fast and simple method using ultra-high performance liquid chromatography with heated electrospray ionization triple quadrupole mass spectrometry (UHPLC/HESI-MS/MS) was developed for the simultaneous determination of aflatoxins B1, G1, B2 and G2, ochratoxin A (OTA), zearalenone (ZEA), HT-2 toxin, T-2 toxin and fumonisins B1 and B2 in crude extracts of various types of nuts. The procedure is based on the simultaneous extraction of selected mycotoxins with a mixture of acetonitrile/water/acetic acid (79:20:1, v/v/v) and defatting the obtained extract with hexane in order to remove the lipids. The validation data indicated that the analysis of different types of crude extracts of nuts is feasible and sensitive enough for determination of the majority of the studied mycotoxins. The recoveries of various nuts matrices ranged between 71.25% and 140.11% with relative standard deviation lower than 12%. The satisfactory recoveries were obtained for the most of mycotoxins using walnut matrix-matched calibration curves indicating the multi-matrix feasibility of the method. The applicability of the method was successfully demonstrated on 17 samples of nuts collected in a region of northern Serbian province of Vojvodina. Total frequency of the occurrence of the selected mycotoxins was 12%.