Analysis for zearalenone and (alpha)-zearalenol in cereals and swine feed using accelerated solvent extraction and liquid chromatography with fluorescence detection

A fast and accurate method for the determination of zearalenone (ZON) and (alpha)-zearalenol ((alpha)-ZOL) in ground wheat samples has been optimised using accelerated solvent extraction (ASE) and liquid chromatography (LC) with fluorescence detection. The effects of the experimentally controllable ASE parameters (solvent composition, temperature, pressure, number of extraction cycles and sample cell size) on the extraction efficiencies of the target analytes have been investigated using wheat samples fortified at the ng g^-1 level. The optimum extraction conditions were obtained using a 11 mL ASE cell, methanol/acetonitrile (50:50 v/v) as the extraction solvent, 1500 psi, 50 °C, a 5 min static time and a 60% flush volume. The extracted samples were analysed using LC with fluorescence detection ((lambda)exc= 271 and (lambda)em=452 nm). The stationary phase was a polar endcapped C18 column and acetonitrile/methanol/water 10/55/35 (v/v/v, 15 mM ammonium acetate) at a flow rate of 1.0 mL min^-1 was used as the mobile phase. The injection volume was set at 8 (mu)L. Mean recovery rates of 98.4% for (alpha)-ZOL (RSD<4.6%) and 96% for ZON (RSD<4.0%) have been obtained for wheat samples fortified with 50–200 ng g^-1 of ZON and (alpha)-ZOL. The optimised procedure has also been applied to the determination of ZON and (alpha)-ZOL in corn, rye, barley, rice and swine feed. Excellent extraction recoveries were achieved for both analytes in all the samples tested, except for (alpha)-ZOL in rice. The developed ASE-LC method has been validated using fortified wheat samples and the results have been compared with those provided by the official AOAC-LC method.