Design of a combined microextraction and back-extraction technique for the analysis of mycotoxins in amaranth seeds

Abstract

A methodology was optimized for the determination of the mycotoxins deoxynivalenol and zearalenone in Amaranthus-based samples. The extraction/preconcentration procedure consisted of an in-phase liquid-liquid microextraction based on the solidification of a floating organic drop followed by a double solvent-assisted back-extraction combined with liquid chromatography-tandem mass spectrometry (DLLME-SFO-SBE). The solvent assisted back-extraction enabled the direct injection of deoxynivalenol (DON) and zearalenone (ZEA) in the ultra-high performance liquid chromatography-tandem mass spectrometry system configured with an electrospray source operated in a positive polarity mode (UHPLC-ESI+-MS/MS). Parameters affecting the efficiency of the back-extraction procedure were evaluated and optimized, including the nature of the back-extractant volume and the agitation effect. Detection and quantification limits were in the range of 0.07−0.73 μg kg−1 and 0.22−0.91 μg kg−1. Acceptable extraction recoveries between 80.35 and 100.05 % and enrichment factors between 16 and 20-fold, with relative standard deviations < 10.12 %, were obtained. The method was successfully applied to the analysis of different types of Amaranthus samples. Concentration levels of deoxynivalenol from 10.62?76.86 μg kg-1 and zearalenone from 9.18?89.29 μg kg−1, were detected in seeds, flours, and the burst of Amaranthus. The proposed methodology is an easy, sensitive, and accurate analytical approach to determine deoxynivalenol and zearalenone in the mentioned food samples.