RAPID PURIFICATION OF FUMONISINS B-3 AND B-4 WITH SOLID-PHASE EXTRACTION COLUMNS

A simple method was developed to isolate fumonisins B-3 and B-4 (FB3 a nd FB4) from cultures of a novel strain of Fusarium moniliforme which produces FB3 and FB4 but does not make FB1 or FB2. Undiluted extract w as loaded onto a 10 g NH2 solid phase extraction cartridge, and the fu monisins were eluted with 5% acetic acid in methanol. The eluate was d iluted with 1.5 vol of water and loaded onto a 10 g tC18 cartridge. Th e fumonisins were eluted with increasing amounts of acetonitrile in wa ter. Complete separation was obtained between the FB3 (277 mg) and FB4 (62 mg) fractions. The fractions were analyzed for purity by three me thods: fluorescence detection of the OPA derivatives, evaporative ligh t-scattering detection of the underivatized fumonisins, and electrospr ay-MS. The fractions from the combined NH2/tC18 method contained more than 90% fumonisins. Recovery of the fumonisins from the extracts exce eded 95%.