Supercritical fluid extraction of macrocyclic lactone mycotoxins in maize flour samples for rapid amperometric screening and alternative liquid chromatographic method for confirmation

A rapid and simple method for the direct screening of macrocyclic lactone mycotoxins (zearalenone, ZON; α-zearalenol, α-ZOL; and β-zearalenol, β-ZOL) in maize flour samples is proposed. The sample screening method comprises supercritical fluid extraction (SFE) and clean-up on Florisil adsorption cartridge of the selected toxic compounds, followed by continuous flow electrochemical detection. Those samples for which the total concentration is close to or above the threshold limit established by legislation (0.200 mg kg−1) are subjected to preconcentration on C18 chromatographic material and liquid chromatographic separation for confirmation purposes. This confirmation method allows the determination of ZON, α-ZOL and β-ZOL in the range between 30 and 300 μg kg−1, with a average relative standard deviation lower than 5.2 in all cases.