Rapid Simultaneous Quantification of Zearalenone and Fumonisin B1 in Corn and Wheat by Lateral Flow Dual Immunoassay

A lateral flow dual immunoassay (LFDIA) was developed for rapid quantitative detection of zearalenone (ZEN) and fumonisin B1 (FB1) in corn and wheat samples on a single test strip. Two test lines and the control line on the nitrocellulose membrane were coated with ZEN and FBI conjugates and goat anti-mouse IgG, respectively. Colloidal gold nanoparticles were conjugated with monoclonal antibodies against ZEN or FBI. The intensity of the test lines was analyzed by a photometric strip reader to determine the concentrations of ZEN and FBI based on the calibration curves of known concentrations versus intensity readings. Test parameters such as types of buffers, ratio of the two gold-labeled antibodies, and dilution of the sample extracts and the gold-labeled antibodies were optimized. The detection limit was 0.35 and 5.23 ng/mL for ZEN and FBI, respectively, and the corresponding detection ranges were 0.94-7.52 and 9.34-100.45 ng/mL, respectively. Spiked and natural samples were analyzed using both LFDIA and liquid chromatography tandem mass spectrometry. The two methods had a good correlation (R-2 = 0.96). The dual quantitative LFDIA is sensitive, rapid, and easy-to-use for on-site testing of a large number of samples.