Evaluation of flow injection mass spectrometry approach for rapid screening of selected pesticides and mycotoxins in grain and animal feed samples

Abstract

A fast screening approach for simultaneous detection of twelve pesticides and seven mycotoxins in food and feed samples using flow injection (FI) mass spectrometry (MS) was developed and evaluated. Ten selected pesticides represented five pairs of structural isomers to challenge their MS differentiation without chromatographic separation. Samples of cereals/grains and animal feed were prepared using QuEChERS extraction, diluted and fortified with the selected contaminants to yield their representative maximum levels (MLs) or maximum residue levels (MRLs). Sensitivity of the developed approach was assessed for qualitative screening of the selected contaminants using triple quadrupole MS/MS and ion mobility (IM) HR-TOFMS. Despite the high complexity of the selected matrices and the absence of chromatography, limits of detection in fortified extracts were below established regulatory levels for 14 and 15 selected contaminants by FI-MS/MS and FI-IM-TOFMS analysis, respectively, in 36–100% samples. Experiments with ion mobility TOFMS did not result in successful separation of pesticide structural isomers. However, for three out of five pairs of pesticide structural isomers: cyproconazole and uniconazole, methiocarb and ethiofencarb, and vernolate and pebulate, unique fragment ions were found and confirmed with HR-QTOFMS for their MS differentiation. The developed approach is sensitive enough for rapid multi-residue screening of some pesticides and mycotoxins in complex samples of food and feed, providing high speed and throughput, simplicity and effective use of high-end instrumentation.