Isolation, Detection, and Quantitation of Zearalenone in Maize and Barley

Abstract

A versatile method for the detection of zearalenone is described, employing options of either thin layer chromatography (TLC), gas-liquid chromatography (GLC), ultraviolet chromatography, GLC-mass spectrometry, or combinations of all of these. Zearalenone is extracted with either a Soxhlet apparatus or the more rapid and convenient batch extraction technique with equal efficiency. Cleanup of the extract involves either a base (NaOH) treatment and partition with water or an acetonitrile- petroleum ether partition. A chloroformethanol (97+3) solvent system is used for analysis by TLC with confirmation by fluorescent properties. The limit of detection on the TLC plate is 0.1 μg, while the sensitivity for the TLC method is about 50 ppb. Best quantitative results are obtained by analytical procedures involving GLC. The limit of sensitivity by GLC is less than 50 ppb. The derivatives dimethoxyzearalenone and methyl oxime-di- TMS-ether-zearalenone are prepared to confirm the presence of zearalenone. Zearalenone can also be analyzed both qualitatively and quantitatively by ultraviolet spectrophotometry. For quantitation, a standard curve is constructed of the absorption at 274 nm. The limit of detection is between 0.1 and 0.5 μg/ml. Analysis by combination GLC and mass spectroscopy is also described along with analysis by multiple ion detection. Per cent recovery is 83.5±7. The method described is suitable for analysis of the concentrations of zearalenone normally encountered in nature and thought to be significant.