Highly selective monoclonal antibody-based lateral flow immunoassay for visual and sensitive determination of conazole fungicides propiconazole in vegetables
Ze-Ke Xu, Ze-Ke Xu, Jingnan Meng, Yi Lei, Xingxing Yang, Yiyong Yan, Liu Hai-hong, Hongtao Lei, Ting-Cai Wang, Xing Shen, Zhen-Lin Xu, Zhen-Lin Xu
Abstract
The conazole fungicide propiconazole is frequently found in vegetables although usage is not allowed. To overcome the high-cost and time-consuming labour requirements of instrumental methods, we developed a simple and visual lateral flow immunoassay for the sensitive determination of propiconazole. A hapten was carefully designed to raise a monoclonal antibody against propiconazole. Bal b/c mice were immunised with the hapten-carrier protein conjugate and a specific monoclonal antibody (mAb) was produced. Based on this mAb, a sensitive immunochromatographic strip assay (ICA) was established for rapid screening of propiconazole in vegetable samples. After optimisation of analytical parameters, the ICA strip showed a detection limit of 0.13 ng g−1 and a linear range from 0.5 to 80 ng g−1 using a strip reader. The assay also can be read by the naked eye with a visual limit of detection of 80 ng g−1. The recoveries for spiked vegetable samples by ICA ranged from 85.2% to 114.9%, with a coefficient of variation less than 11.7%. The assay time is within 45 min for a single sample including the sample pre-treatment. For spiked and blind samples, the detection capability of ICA was equivalent to liquid chromatography-mass spectrometry.