A rapid, portable, and semi-quantitative immunochromatographic strip was developed for rapid and visual detection of alternariol monomethyl ether (AME). For this purpose, the anti-AME monoclonal antibody (mAb) was prepared and identified. AME coupled to bovine serum albumin (BSA) via methyl 4-bromobutanoate was prepared as immunogen. The recoveries of AME in spiked cherry and orange fruits determined by competitive ELISA were 86.1% and 80.7%, respectively. A colloidal gold nanoparticle (CGN) and CGNs-mAb conjugate were synthesized, and on this basis, a competitive colloidal gold immunochromatographic strip was developed and applied to the detection of AME toxin in fruit samples. The intensity of red density of the test line (T line) is inversely proportional to AME concentration in the range 0.1-10 ng/mL. The visual limit of detection (LOD) of AME was found to be about 10 ng/mL. The semi-quantitative detection can be completed in 10 min. Moreover, the immunochromatographic strip has lower cross-reactivity with AME analogues, and it has a good stability performance (following 3 months of storage). Hence, the colloidal gold immunochromatographic strip could be used as a semi-quantitative tool for the on-site, rapid, and visual detection of AME in fruit.
Keywords: alternariol monomethyl ether (AME); colloidal gold nanoparticle; competitive ELISA; immunochromatographic strip test; monoclonal antibody.