A fluorescence polarization immunoassay for the detection of zearalenone in corn

The aim of this study was to develop a fluorescence polarization immunoassay (FPIA) that is based on the change in fluorescence polarization of fluorescently labeled small antigen when bound by a specific antibody, for use as a screening test for zearalenone (ZEN) in cereals and their products. Syntheses of fluorescein-labeled ZEN tracers containing three linkers of different lengths (2, 3 and 6-carbon bridge), ethylenediamine, 1,2-diaminopropane and hexamethylenediamine, were explored and their binding response with ZEN-specific antibody was evaluated. A fluoresceinthiocarbamyl hexamethylenediamine-labeled ZEN conjugate (ZEN-HMDF), which contain a 6-carbon bridge, was found to be the most sensitive FPIA for detection of ZEN. When tested on corn matrix the FPIA using the ZEN-HMDF tracer showed a detection range for ZEN of 150–1000 μg kg −1 with a detection limit of 137 μg kg −1, and required less than 2 min per sample to carry out, excluding extraction time. The average recovery from spiked corn samples was 106.4 ± 12.5%. Comparative analyses of 70 naturally occurring cereals and their products using FPIA, enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography (HPLC) showed that the coefficients of determination ( r 2) between FPIA and ELISA, and between FPIA and HPLC were 0.76 and 0.72, respectively. These results suggest that the ZEN-HMDF tracer is suitable for FPIA, which has potential as a screening tool for ZEN in grains without the need for a complicated clean-up procedure.