Effect of temperature and solvent composition on extraction of fumonisins B-1 and B-2 from corn products

Fumonisins B-1 and B-2 were extracted from naturally contaminated corn prod ucts by using different extraction solvent compositions (methanol-water, ac etonitrile-methanol-water, ethanol-water, and 100% water) and a range of te mperatures from ambient to 150 degrees C. Ground samples of several corn pr oducts and I rice sample were mixed with an adsorbent material (Hydromatrix (TM)), and the fumonisins were extracted in 2 sequential 5 min static extra ctions at various temperatures. The combined extracts were cleaned up and a nalyzed by reversed-phase liquid chromatography with fluorescence detection after o-phthaldialdehyde-mercaptoethanol derivatization, The results showe d a clear influence of temperature and solvent composition on recovery of f umonisins from some matrixes. With acetonitrile-methanol-water (1 + 1 + 2) the quantity of fumonisins extracted from naturally contaminated taco shell s almost tripled in going from 23 degrees to 80 degrees C, and increased by another 30% when ethanol-water (3 + 7) was used as extraction solvent at 8 0 degrees C. Similar results were obtained with nacho chips. These effects were less pronounced with cornmeal, and small differences due to temperatur e and solvent composition were observed for corn flakes and rice. The ethan ol-water extraction solvent combinations were specifically evaluated in an effort to use the cheapest, least toxic, and most environmentally friendly solvents for organic residue analysis. At 80 degrees C, ethanol-water combi nations performed equally or better than methanol-water (8 + 2) or acetonit rile-methanol-water (1 + 1 + 2), combinations which are commonly used for f umonisin extractions. Even 100% water was successful for extracting fumonis ins from the products, except for rice. However, increased amounts of water created technical problems and required an increased amount of Hydromatrix in the samples prior to extraction.