Analysis of trichothecenes in laboratory rat feed by gas chromatography-tandem mass spectrometry.
Animal feed can be contaminated with various mycotoxins. To ensure animal health and safe food and feed production, the European Commission has recommended increased monitoring of the co-occurrence of deoxynivalenol, zearalenone, ochratoxin A, fumonisin B(1) and B(2), T-2 and HT-2 toxin in feed. Thus, there is a need for an analytical method that enables their simultaneous detection and quantification. This paper describes the development and in-house validation of such a method, in which the mycotoxins were extracted from spiked and naturally contaminated cereal-based compound feed, corn and wheat. The extracts were divided into two aliquots where one was diluted and then analysed directly and the other was cleaned by using MultiSep(®)226 and then diluted and analysed. Separation and detection was achieved with LC-ESI-MS/MS by using a triple quadrupole instrument in the SRM mode. The precision (in terms of intra-day repeatability and inter-day reproducibility), accuracy, linearity, apparent recovery and expanded measurement uncertainty in feed, corn and wheat were evaluated. The LODs ranged from 1.0 to 72 μg/kg, and the LOQs ranged from 2.5 to 115 μg/kg. The apparent recovery was higher than 86% for all the mycotoxins, and the precision was better than that defined by the Horwitz equation for all concentrations. Proficiency test materials were analysed to assess the accuracy of the method, and the results were satisfactory for all seven mycotoxins. The method will be used to monitor the occurrence of these mycotoxins in products intended for animal feeding in Sweden.