Rapid and sensitive detection of cyhalofop-butyl in foods using a gold nanoparticle-based lateral-flow strip

In this study, we prepared a highly sensitive monoclonal antibody (mAb) against Cyhalofop-butyl (Cyh) by indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). Based on this mAb, an immunochromatographic strip (ICA) was established to detect Cyh in corn and brown rice samples. Through screening different coating antigens and antibodies, the half-maximum inhibitory concentration (IC50) of the highly specific Cyh mAb 1A3 was 2.2 ng/mL, and the detection linear range (IC20-IC80) was 0.5–5.2 ng/mL. When Cyh in corn samples was detected by ICA, the detection limit of the T line elimination value was 100 μg/kg, and the detection limit for colorimetric value was 25 μg/kg. When the detection sample was brown rice, the detection limit of the T line elimination value was 100 μg/kg, and the detection limit for colorimetric value was 12 μg/kg. The results of recovery experiments for both ic-ELISA and LC-MS/MS were consistent with those of the test results when using the ICA. The ICA test strip met the requirements for on-site rapid detection of Cyh in corn and brown rice samples. Therefore, this method is suitable for real-time detection and monitoring of agricultural products as well as during plant growth, harvesting, transportation, storage, and sales, thereby guaranteeing the safety of consumers.