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United States Department of Agriculture

Agricultural Research Service

Title: Measurement of Fumonisins in Corn with a Fiber-Optic Fluoroimmunosensor

Authors
item Thompson, Vicki
item Maragos, Chris

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 10, 1997
Publication Date: N/A

Technical Abstract: A fiber-optic immunosensor was used to determine concentrations of the mycotoxin fumonisin B1 (FB1) in both spiked and naturally contaminated corn samples. Samples were extracted with a mixture of methanol/water. Two methods were used to prepare the methanolic corn extracts before introduction to the immunosensor: 1) simple dilution of the methanolic corn extract; and 2) affinity column cleanup. The sensor displayed an IC50 of 70 ng FB1/ml when toxin was introduced in phosphate buffered saline. Simple dilution of methanolic corn extracts yielded an assay with an IC50 equivalent to 25 ug FB1/g corn and a limit of detection of 3.2 ug/g corn, while affinity cleanup of corn extracts yielded an assay with an IC50 of 5 ug FB1/g corn and a limit of detection of 0.4 ug FB1/g corn. The difference in sensitivity between the two cleanup techniques was due to concentration of fumonisins obtained from the affinity cleanup procedure. Naturally contaminated corn samples were also analyzed after either simple dilution or affinity column cleanup. For comparison the naturally contaminated corn samples were analyzed with an HPLC method after isolation of the fumonisins with strong anion exchange (SAX) solid phase extraction cartridges. The SAX/HPLC method and the immunosensor method agreed well except when large amounts of other fumonisins (i.e. fumonisin B2) were present. This was due in part to the cross-reactivity of the monoclonal antibody with other fumonisins. The immunosensor has the potential to screen individual corn samples for fumonisins within six minutes, an improvement over currently available FB1 detection methods.

Last Modified: 4/20/2014
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