Development of a rapid and simultaneous immunochromatographic assay for the determination of zearalenone and fumonisin B1 in corn, wheat and feedstuff samples

A rapid and simultaneous immunochromatographic assay for the detection of zearalenone and fumonisin B1 was developed and optimized. Specific monoclonal antibodies against zearalenone or fumonisin B1, labeled with colloidal gold, were used as probes on an immunochromatographic strip for dual detection. The conjugates of zearalenone and fumonisin B1, as two test lines, were coated onto a nitrocellulose membrane to determine whether the samples contained both mycotoxins. The conditions were optimized, investigating the diameter of the gold nanoparticles, the concentrations of the conjugates, the monoclonal antibodies, and the buffer constituents and materials of the strip. Trehalose and tetronic 1307 were added into the buffer, and 25 nm colloidal gold nanoparticles were considered to give improved performance. The single immunochromatographic strips for either zearalenone or fumonisin B1 did not have cross-reactivity with fumonisin B1, zearalenone, deoxynivalenol or aflatoxin B1. The sensitivity levels were 6 and 50 ng/mL for zearalenone and fumonisin B1 on the dual test strip, respectively. In total, 60 samples (including corn, wheat and feedstuffs) were determined using the dual test strip, indirect competitive enzyme-linked immunosorbent assays (IC-ELISAs) and liquid chromatography-mass spectrometry. The results of strips were shown to have good agreement with the enzyme-linked immunosorbent assays and liquid chromatography-mass spectrometry (LC-MS). The indirect competitive enzyme-linked immunosorbent assays also had a strong correlation with the commercial ELISA kits when compared using spiked samples. The colloidal gold immunochromatographic dual strip could detect samples containing zearalenone and fumonisin B1 rapidly (less than 15 min) and accurately (due to the monoclonal antibody), more easily and at a lower cost compared to other detection methods (chromatography and enzyme-linked immunosorbent assays).

Brief summary: ZEN conjugate, FB1 conjugate and goat anti-mouse antibody were sprayed as Test 1 (T1) line, Test 2 (T2) line and Control (C) line, respectively. This dual strip could detect zearalenone and fumonisin B1 in different kinds of samples simultaneously, rapidly (less than 15 min) and accurately.Highlights► Rapid and simultaneous detection of zearalenone and fumonisin B1 in different kinds of samples were developed. ► The sensitivity levels of this dual strip were 6/50 ng/mL for zearalenone and fumonisin B1, respectively. ► The dual strip with 25 nm gold nanoparticle was most sensitive and stable than other kinds of nanoparticles. ► The kinds of additives in buffers to improve the stability and sensitivity of this strip were selected and optimized.