Method of analysis for deoxynivalenol and zearalenone from cereal grains

Abstract

A method was developed to determine deoxynivalenol and zearalenone in corn, wheat, oats, rice and barley. The toxins are extracted with methanol/water (50:50, v/v) (2×) and partially purified by partitioning into ethyl acetate and then defatting with acetonitrile-petroleum ether. Toxins are isolated by silica gel column chromatography. Interfering materials are removed from the column with benzene; zearalenone is eluted with benzene/acetone (95:5, v/v), and after a column wash of chloroform/methanol (95:2, v/v), deoxynivalenol is eluted with chloroform/methanol (95:5, v/v). Zearalenone is quantitated by thin-layer chromatography and deoxynivalenol by gas-liquid chromatography of the trimethylsilyl derivative. The detection limit is about 0.02 µg/g for each toxin. Recoveries of added toxins varied with substrate and level of toxins. Recovery of deoxynivalenol ranged from 58% for 1 ppm in rice to 108% for 1 ppm in corn. Average recoveries for all levels (1, 2 and 5 ppm) ranged from 69% for barley to 89% for oats. Recovered zearalenone ranged from 40% for 5 ppm in wheat to 100% for 1 ppm in barley. Average recoveries for zearalenone at 1, 2 and 5 ppm varied from 53% for wheat to 87% for rice.