Rapid purification of fumonisins and their hydrolysis products with solid-phase extraction columns

Fumonisins B-3 and B-4 (FB3 and FB4) were recovered from the 50:50 acetonitrile/water extract of corn cultures of a strain of Fusarium moniliforme that does not make FB1 or FB2 by stirring the extract with IRA-68, a weak anion-exchange resin. The fumonisins were desorbed with 5% acetic acid in the same solvent. After dilution with water, the desorbed fumonisins were separated into FB3 (FB3 and FA(3)) and FB4 (FB4, FC4, and FA(4)) fractions with a tC(18) solid-phase extraction (SPE) cartridge. The FB3 fraction was then separated into FB3 and FA(3) by using an NH2 SPE cartridge and eluting with 5% acetic acid and increasing amounts of acetonitrile in water. Finally, FB1 and FA(3) were hydrolyzed with calcium hydroxide. After recovery from the reaction mixture using a tC(18) cartridge, the hydrolyzed and partially hydrolyzed analogues were separated and the unreacted fumonisins recovered by using an NH2 cartridge, initially in the normal-phase mode with increasing amounts of water in acetonitrile and then in the reversed-phase mode after the addition of 5% acetic acid to the solvent and eluting in the reverse order.