Determination of fumonisins B1 and B2 produced by isolates of Gibberella fujikuroi complex in corn and rice

Fumonisins B1 (FB1) and 2 (FB2) are the major mycotoxins produced mainly by some strains of Gibberella fujikuroi complex. fungi that occur worldwide on cereals. Contamination of food and feed with these fungi has been associated with a number of diseases in animals and humans. In this work, some steps in the analysis of FB1, and FB2, by HPLC to reduce analysis time, costs and impurities in the extracts are evaluated. Fumonisins were extracted with acetonitrile/water (1:1), and the extract was cleaned up by solid-phase extraction through C,, cartridges. These cartridges have the advantage over SAX cartridges of being less time-consuming and producing cleaner extracts. The fumonisins were eluted from the cartridge with methanol/water (7:3) and derivatized with o-phthaldialdehyde and 2-mercaptoethanol to yield highly fluorescent derivatives. Reversed-phase HPLC with fluorescence detection is used for the final separation and determination. Under these conditions, the analytical method proved to be linear for mycotoxin amounts in the range from 10-4000 ng. The detection limits in corn and rice samples (at a signal-to-noise ratio of 3: 1) were 5 ng/g for both fumonisins.