Rapid immunoaffinity-based method for determination of zearalenone in cornby fluorometry and liquid chromatography

An immunoaffinity-based method was developed to determine zearalenone in co rn, Corn samples were extracted in acetonitrile-water (90 + 10, v/v), appli ed to an immunoaffinity column, and eluted with methanol. The isolated toxi n was quantitated either by reaction with aluminum chloride hexahydrate (Al Cl3. 6H(2)O) prior to measurement with a fluorometer or injection into a li quid chromatographic (LC) system with a fluorescence detector. Performance was evaluated in terms of antibody specificity, limit of detection, percent age recovery, precision, column capacity, assay linearity, and comparison w ith AOAC Official Method 985.18. With the immunoaffinity column cleanup pro cedure, only zearalenone and its metabolites were recognized by the antibod y (greater than or equal to 75% recovery). Limits of detection were 0.10 mu g/g for the fluorometer and 0.10 or 0.0025 mu g/g (sensitive method) for t he LC method. Percentage recovery averaged 105% (fluorometer) and 93% (LC m ethod), with average relative standard deviations (RSDs) of 15.7 and 9.3%. Naturally contaminated samples gave comparable RSDs of 8.3 and 9.9% for the fluorometer and LC methods, respectively. Column capacity was 4.0 mu g wit h 89% recovery. Assay linearity was comparable for both methods (r(2) = 0.9 98). Optimum assay ranges were 0.10-5.0 mu g/g for the fluorometer and 0.10 -50 or 0.0025-5.0 mu g/g (sensitive method) for the LC method. Comparative analysis of 17 naturally contaminated corn samples using ZearalaTest LC and the official AOAC LC method for detection of zearalenone showed that Zeara laTest is statistically comparable to the AOAC Official Method 985.18 (r(2) = 0.747).