Time-resolved fluoroimmunoassay of zearalenone in cereals with a europium chelate as label

A competitive indirect time-resolved fluoroimmunoassay (TRFIA) was developed for detection of zearalenone (ZEN) in cereals, in which ZEN conjugated to bovine serum albumin (BSA) is used as solid-phase antigen. A competitive indirect TRFIA was conducted by simultaneously incubating ZEN in standard or extracted samples with anti-ZEN monoclonal antibody over ZEN-BSA coated plates, and then determining the bound ZEN monoclonal antibody with goat anti-mouse europium conjugate. Samples were extracted with methanol/water (70:30, v/v), then was subject directly for TRFIA without any clean-up procedure. The sensitivity of this method was 0.2 ng/ml. The measuring range of the ZEN-TRFIA was 0.2–200 ng/ml. The mean within-assay and between-assay coefficients variation of standard curve were both less than 10%. The recoveries of spiked cereals samples ranged from 76%–132%. 10 corn and 6 wheat corn samples were tested, ZEN values obtained by this method agreed well with those obtained by commercial ELISA kit. It was concluded that this new method is suitable for rapid screening of ZEN in corn and wheat.