Dual-wavelength fluorescence polarization immunoassay to increase information content per screen: Applications for simultaneous detection of total aflatoxins and family zearalenones in maize

To increase information content per screen, a dual-wavelength, homologous and high-throughput fluorescence polarization immunoassay (DWFPIA) for simultaneous detection of total aflatoxins (AFs) and family zearalenones (ZENs) was developed. Aflatoxin B1 (AFB1) and zearalanone (ZAN) were labeled with different fluoresceins, and then combined with corresponding broad-specific antibodies to develop the DWFPIA. Under optimal conditions, the half maximal inhibitory concentrations of the FPIA in buffer were 2.68 μg/L and 4.08 μg/L for total four AFs (the weight ratio of AFB1: Aflatoxin B2: Aflatoxin G1: Aflatoxin G2 was 1: 1: 1: 1) and six ZEN analogs (the weight ratio of ZEN: ZAN: α-zearalenone: β-zearalenone: α-zearalanone: β-zearalanone was 1: 1: 1: 1: 1: 1) by mixing equal volumes (1: 1, v/v), respectively. The corresponding limit of detection values in maize flour samples were 4.98 μg/kg and 11.03 μg/kg, and the mean recoveries ranged from 78.6 to 103.6% with the coefficients of variation below 19.2%. The whole detection procedure, including sample preparation, took less than 30 min. Finally, the DWFPIA was applied to screen naturally contaminated maize flour samples, and the detection data were similar to those with HPLC-MS/MS.