ROBOTIC AUTOMATED-ANALYSIS OF FOODS FOR AFLATOXIN

Immunoaffinity column-based sample preparation procedures for determin ation of aflatoxins B-1, B-2, G(1), and G(2) in several food matrixes and aflatoxin M(1) in milk have been automated by using flexible autom ation, or robotics, Components used to assemble the system were purcha sed commercially or developed and built in-house. A liquid-level senso r developed in-house to assist elution of the immunoaffinity column is described. After immunoaffinity column cleanup, aflatoxins are separa ted by reversed-phase liquid chromatography and determined by fluoresc ence without derivatization. Mean recoveries of aflatoxins B-1, B-2, a nd G(1) added to corn and nuts at 9-36 ng/g total aflatoxins were >85% (coefficient of variation [CV] = 16%). Recoveries of aflatoxin G(2) a veraged 50% (CV = 28%). Recoveries of aflatoxin M(1) added to milk at 0.12-0.50 ng/mL averaged 78% (CV = 19%). The ability of the automated system to reproduce its results is demonstrated by the fact that the C V of replicate assays is generally better than 10%. Comparability betw een the automated procedure and the AOAC official method is demonstrat ed.