| Abstract
| - Fumonisins, mycotoxins produced by certain species of Fusaria, are commonly found worldwide ascontaminants in maize. This paper reports the development of a rapid, portable fluorescencepolarization-based assay for fumonisins in maize. The assay was based on the competition ofunlabeled fumonisin, from a sample, with a fluorescently tagged fumonisin (FB1-FL) for a fumonisin-specific monoclonal antibody in solution. The fluorescence polarization (FP) of the tagged fumonisinwas increased upon binding with the antibody. In the presence of free toxin, less of the FB1-FL wasbound and the polarization signal was decreased. The assays were very simple to perform, requiringonly mixing of an aqueous extract of maize with the tagged fumonisin and antibody, and required<2 min per sample, excluding extraction time. Two permutations of the assay were tested, onewith each sample matrix serving as its own blank, and the other with all of the samples comparedrelative to a PBS blank with normalization of the data similar to an ELISA. The limit of detection,defined as the toxin content associated with a fluorescence polarization signal 5 standard deviationsfrom that of a fumonisin-free control, was 0.5 μg of FB1/g in spiked maize. Recoveries from spikedmaize over the range of 0.5−20 ppm averaged 94.3 ± 13.8%. Forty-eight samples of field-contaminated maize were tested by the FP and an established HPLC method, with a good correlationbetween the two (r2 = 0.85−0.88). For these samples, the two variations of the FP assay alsocompared well to one another (r2 = 0.97), suggesting the assay principle is very robust. The results,combined with the speed and ease of use for the assay, suggest that this technology has substantialpotential as a screening tool for mycotoxins in foods. Keywords: Mycotoxin; fumonisin; fluorescence polarization; maize
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