Collaborative investigation of matrix effects in mycotoxin determination by high performance liquid chromatography coupled to mass spectrometry

Liquid chromatography coupled to mass spectrometry (LC-MS) is a commonly used technique for mycotoxin determination in food and feed. However, accuracy and reliability of the obtained results can suffer from ion suppression/enhancement caused by co-eluting matrix components. Inter-laboratory study concerning relative and absolute matrix effects (MEs) in various food and feed matrices was carried out. The applicability of commonly used strategies in ME reduction were tested in the quantitative determination of nivalenol, deoxynivalenol, fumonisin and B-2, and zearalenone in complex feed matrices. 'In house' validated LC-MS methods were applied. The relative MEs were assessed on the different food/feed sample sets. Cereal based- and hay/silage feed were used as complex model matrices for absolute ME assessment. The relative MEs within the different sample sets were in range of 3-72%. The absolute MEs for all analytes were in the range of 60-100% and 7-187% for cereal based and hay silage feed, respectively. The use of any purification technique helped to improve absolute MEs for some analytes. Changes in LC conditions did not eliminate ME occurrence. Shifting from electrospray ionization in positive mode (ESI+) to electrospray ionization in negative mode (ESI-) improved MEs for early eluting analytes in hay/silage feed. The choice of ion source highly depended on the analyte-matrix combination.