Fluorescence Polarization Immunoassay for Highly Efficient Detection of Imidaclothiz in Agricultural Samples

A homogeneous fluorescence polarization immunoassay (FPIA) based on a monoclonal antibody for the detection of imidaclothiz was developed. Two fluorescein-labeled imidaclothiz tracers containing two different bridge lengths were synthesized and purified. Under optimal conditions, the 4-aminofluorescein-labeled imidaclothiz conjugate (AMF-labeled imidaclothiz), which contains a shorter bridge length, showed a higher sensitivity in the FPIA for detecting imidaclothiz, and the full analysis was achieved in less than 11 min. The IC50 and limit of detection (LOD, IC10) were 87.94 ± 10.18 and 0.57 ± 0.16 μg/L, respectively. The spiked recoveries were 83 to 117 % measured in tomato, pear, rice, apple, cucumber, cabbage, and paddy water, with RSDs of 5 to 12 %. Furthermore, the results of FPIA for the authentic samples correlated well with those acquired by HPLC. Overall, the developed FPIA provided a simple, rapid, sensitive, and accurate method that was used for the quantitative detection of imidaclothiz in agricultural samples.