Determination of zearalenone content in cereals and feedstuffs by immunoaffinity column coupled with liquid chromatography

The zearalenone content of maize, wheat, barley, swine feed, and poultry fe ed samples was determined by immunoaffinity column cleanup followed by liqu id chromatography (IAC-LC). Samples were extracted in methanol-water (8 + 2 , v/v) solution. The filtered extract was diluted with distilled water and applied to immunoaffinity columns. Zearalenone was eluted with methanol, dr ied by evaporation, and dissolved in acetonitrile-water (3 + 7, v/v). Zeara lenone was separated by isocratic elution of acetonitrile-water (50 + 50, v /v) on reversed-phase C-18 column. The quantitative analysis was performed by fluorescence detector and confirmation was based on the UV spectrum obta ined by a diode array detector. The mean recovery rate of zearalenone was 8 2-97% (RSD, 1.4-4.1 %) on the original (single-use) immunoaffinity columns. The limit of detection of zearalenone by fluorescence was 10 ng/g at a sig nal-to-noise ratio of 10:1 and 30 ng/g by spectral confirmation in UV. A go od correlation was found (R-2 = 0.89) between the results obtained by IAC-L C and by the official AOAC-LC method. The specificity of the method was inc reased by using fluorescence detection in parallel with UV detection. This method was applicable to the determination of zearalenone content in cereal s and other kinds of feedstuffs. Reusability of immunoaffinity columns was examined by washing with water after sample elution and allowing columns to stand for 24 h at room temperature. The zearalenone recovery rate of the r egenerated columns varied between 79 and 95% (RSD, 3.2-6.3%). Columns can b e regenerated at least 3 times without altering their performance and witho ut affecting the results of repeated determinations.