Quantitative analysis of Fusarium mycotoxins in maize using accelerated solvent extraction before liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry

Abstract

A method for the simultaneous quantitative determination of deoxynivalenol (DON), fumonisin B1 (FB1) and zearalenone (ZEN) in maize by liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometry (LC-APCIMS/MS), using stable isotopically labelled and structural analogues internal standards, is described. The procedure involves accelerated solvent extraction followed by two solid-phase clean-up steps on strong anion exchange resin and a Mycosep® column. Typical recoveries were calculated by spiking blank maize at three different concentrations for deoxynivalenol (200, 400 and 1000 μg kg⁻¹) at 70%, for fumonisin B1 (100, 200 and 1000 μg kg⁻¹) at 90%, and for zearalenone (50, 100 and 200 μg kg⁻¹) at 40%. LC-APCIMS/MS analyses were realized in collision-induced dissociation on an ion-trap instrument to provide a high degree of selectivity and sensitivity. Extraction of ions from two transition reactions, monitored by LC-APCIMS/MS for each analyte, enabled a limit of detection for DON, FB1 and ZEN at, respectively, 10, 20 and 3 μg kg⁻¹, and a limit of quantification at, respectively, 50, 50 and 10 μg kg⁻¹. The robustness of the method was also evaluated with the analysis of wheat samples.

Keywords:

• mycotoxins
• Fusarium
• deoxynivalenol
• fumonisin B1
• zearalenone
• maize
• accelerated solvent extraction (ASE)
• solid-phase extraction
• atmospheric pressure chemical ionization tandem mass spectrometry (APCI-MS/MS)

Acknowledgements

The authors thank Alain Pittet and Dr Richard Stadler, Nestlé Research Center, for critically reading the manuscript and Adrienne Perisset, also Nestlé Research Center, for technical assistance.