ANALYTICAL DETERMINATION OF FUMONISINS AND OTHER METABOLITES PRODUCED BY FUSARIUM MONILIFORME AND RELATED SPECIES ON CORN

Authors: Plattner, Ronald; Weisleder, David; Poling, Stephen

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Proceedings
Publication Acceptance Date: 11/17/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: Fumonisins are toxic compounds that are made by a fungus that is often found growing on corn and corn products. There is a high level of interest in fumonisins because fumonisin contaminated corn has caused animal disease problems and because the fumonisins are suspected carcinogens and thus may pose a risk factor to humans. This paper describes methods to measure these compounds in corn and the identification of two new fumonisins.

Technical Abstract: Fumonisins are most widely measured as fluorescent derivatives from reactions involving the free primary amine functional group. While this affords a highly sensitive derivative, there are several serious drawbacks to this method. First, the detection which is based on the fluorescence of the derivative rather than a property of the fumonisin homologs is much more susceptible to interference from unrelated compounds possessing a free amine group. Second, fumonisin homologs and analogs that do not have the primary amine group do not form the derivative and thus are not detected. This paper reports two methods to measure underivatized fumonisins. Separation of compounds is achieved by HPLC and detection is by either a laser light scattering detector or by electrospray MS. Good agreement was obtained on levels of fumonisin B1 determined by derivatization with orthophtalaldehyde and fluorescent detection and by analysis of the underivatized compound with the light scattering detector. Although the signal from latter was at least 50 fold less sensitive, it was adequate for analysis of laboratory culture extracts and it may be possible to analyze larger aliquots of sample extract and obtain reasonable detection limits for some naturally contaminated samples. Electrospray MS is an ideal detection method for fumonisins. Detection of as little as one nanogram injected with good chromatographic resolution and reasonable signal-to-noise is obtained. The response is linear across the range from low nanogram to about 1 microgram.