AUTOMATED AFFINITY LIQUID-CHROMATOGRAPHY SYSTEM FOR ONLINE ISOLATION,SEPARATION, AND QUANTITATION OF AFLATOXINS IN METHANOL-WATER EXTRACTSOF CORN OR PEANUTS

An automated liquid chromatography (LC) procedure has been developed f or the determination of aflatoxins in corn and peanuts. The automated LC system consists of the following: two pumps, an autosampler, an iso lation column (immunoaffinity or methacrylate copolymer), an automated switching valve, a C18 column, an electrochemical cell, a fluorescenc e detector, and a data system. Filtered methanol: water (75:25) extrac ts of the test portions are injected into the LC system. With the swit ch in position 1, water is pumped through the autosampler and isolatio n column and then discarded. With the switch in position 2, the mobile phase consisting of methanol:acetonitrile:water (26:18:56), 1 mM KBr, and 1 mM HNO3 is pumped through the isolation column, C18 column, ele ctrochemical cell, and detector. Aflatoxins B1 and G1 react with elect rochemically generated bromine to form fluorescent derivatives. Both i solation columns can be used for >50 injections. Recovery of aflatoxin s from both commodities spiked at 5-30 ng/g was about 85%.